JPH0816802B2 - Color toner - Google Patents

Description

The present invention relates to a color toner for visualizing an electrostatic latent image in an image forming method such as electrophotography and electrostatic recording.

[Prior Art] As image forming apparatuses such as color copying machines for electrophotography have become widespread in recent years, their applications have been widespread and demands on their image quality have become strict. General photos,
In the copying of images such as catalogs and maps, it is required to reproduce extremely minute and faithful reproduction without crushing or breaking even a minute portion.

Further, recently, in an image forming apparatus such as a color copying machine for electrophotography which uses a digital image signal, a latent image is formed by gathering dots having a constant potential, and a solid portion, a halftone portion and a light portion are formed. Is expressed by changing the dot density. However, when the toner particles do not faithfully adhere to the dots and the toner particles protrude from the dots, it is impossible to obtain the gradation of the toner image corresponding to the ratio of the black and white dot densities of the digital latent image. There is a problem. Furthermore, in order to improve the image quality, if the dot size is reduced to improve the resolution, the reproducibility of the latent image formed from minute dots becomes more difficult, and the resolution and especially the gradation of the highlight part The image tends to be poor in sharpness and lack in sharpness.

In addition, although the image quality is good in the initial stage, the image quality may deteriorate during continuous copying or printing. It is considered that this phenomenon occurs because, during continuous copying or printing, only toner particles that are easily developed are first consumed, and toner particles having poor developability accumulate and remain in the developing machine.

So far, some developers have been proposed for the purpose of improving image quality. Japanese Unexamined Patent Publication No. 51-3244 provides a non-magnetic toner intended to improve image quality by controlling the particle size distribution. In the toner, 8 to
The toner mainly has a particle size of 12 μm and is relatively coarse. With this particle size, according to the study of the present inventors, it is difficult to form a uniform “paste” on the latent image, and when the particle size is 5 μm or less,
From the characteristic that the particle size distribution is broad, the uniformity is also likely to be deteriorated due to the characteristics that the particle size distribution is broad and the particle size distribution is broad and the particle size distribution is broad. In order to form a clear image using a toner having such a rough toner particle and a broad particle size distribution, the toner particles are superposed in a thick manner to fill the space between the toner particles to form an apparent image. There is also a problem that it is necessary to increase the image density, and the amount of toner consumption required to obtain a predetermined image density increases.

Further, JP-A-54-72054 proposes a non-magnetic toner having a sharper distribution than the former.
The size of the particles having an intermediate weight is as coarse as 8.5 to 11.0 μm, and there is still room for improvement as a high-resolution color toner that faithfully reproduces a minute dot latent image.

In JP-A-58-129437, the average particle size is 6-10 μm.
A non-magnetic toner having a maximum number of particles of 5 to 8 μm has been proposed, but the number of particles of 5 μm or less is as small as 15% by number or less, and an image lacking sharpness tends to be formed.

According to a study by the present inventors, it was found that toner particles of 5 μm or less clearly reproduce minute dots of a latent image and have a main function of dense toner paste on the entire latent image. . In particular, in the electrostatic latent image on the photosensitive member, electric lines of force are concentrated, so that the edge portion, which is a contour, has higher electrolytic strength than the inside, and the sharpness of the image quality is determined by the quality of the toner particles gathered in this portion. According to the study by the present inventors, it has been found that the amount of particles of 5 μm or less is effective for solving the problem of highlight gradation.

However, when the toner particle size is reduced and the number of toner particles having a particle size of 5 μm or less is increased, the cohesiveness of the toner itself is increased, which causes a problem that the mixing property with the carrier is lowered or the fluidity of the toner is lowered. Will end up.

[Problems to be Solved by the Invention] An object of the present invention is to provide a color toner which solves the above problems.

Further, an object of the present invention is to provide a color toner having a high image density, excellent fine line reproducibility and excellent highlight gradation.

A further object of the present invention is to provide a color toner whose performance does not change even after long-term use.

A further object of the present invention is to provide a color toner whose performance does not change with environmental changes.

A further object of the present invention is to provide a color toner having excellent transferability.

Further, an object of the present invention is to provide a color toner capable of obtaining a high image density with a small consumption amount.

Further, an object of the present invention is to provide resolution, highlight gradation, and image forming apparatus using a digital image signal.
The present invention provides a color toner capable of forming a toner image having excellent fine line reproducibility.

[Means and Actions for Solving the Problems] The present invention relates to a color toner containing non-magnetic toner particles containing a binder resin and a colorant, and two or more kinds of fine powders.
And a color toner applied to a developer having magnetic particles, wherein the color toner has a volume average diameter of 6 to 10 μm, and
15-40% by number of toner particles having a particle diameter of less than or equal to μm are contained, and 0.1% of toner particles having a particle diameter of 12.7 to 16.0 μm are included.
To 5.0 vol%, toner particles having a particle size of 16 μm or more are contained by 1.0 vol% or less, and toner particles of 6.35 to 10.1 μm are represented by the following formula. And the apparent viscosity of the color toner is in the range of 10 ^{4 to} 5 × 10 ⁵ poise at 100 ° C. and 5 × 10 ^{4 to} 5 × 10 ⁶ poise at 90 ° C. The endothermic peak value is from 58 to 72 ° C., the color toner is, as the fine powder, (i) the chargeability of the magnetic particles is the same as that of the toner particles, and the absolute value of the triboelectric charge amount is Of 50 μC / g or more and a specific surface area S _A by the BET method of 80 to 300 m ² / g is contained in the toner particles in an amount of a% by weight based on the toner particles, and (ii) the magnetic particles Has a polarity opposite to that of the toner particles,
The spherical resin particles B having a specific electric resistance in the range of 10 ⁶ to 10 ¹⁴ Ω · cm and a volume average particle diameter of 0.1 to 1.0 μm are contained in an amount of b% by weight with respect to the toner particles. The present invention relates to a color toner characterized in that the content of the inorganic oxide A and the content of the resin particles B satisfy the following formula 0.3 ≦ a + b ≦ 1.5.

The color toner of the present invention containing the above-mentioned two or more kinds of fine powders and having the above-mentioned particle size distribution is capable of faithfully reproducing the latent image formed on the photoconductor, and has a halftone dot and a digital image. Such a minute dot latent image is also excellently reproduced, and particularly an image having excellent gradation and resolution in the highlight portion is provided. Furthermore, high image quality can be maintained even when copying or printing is continued, and even in the case of high-density images, good development can be performed with a toner consumption amount lower than that of conventional non-magnetic toner. Also, it has advantages in terms of performance and miniaturization of the copying machine or printer body.

In the color toner of the present invention, 15 to 40% by number (preferably 20 to 35) of color toner particles having a particle diameter of 5 μm or less are used.
It is one of the features that the number is%). In the conventional color toner, the color toner particles having a particle size of 5 μm or less are difficult to control the charge amount, impair the fluidity of the color toner, and are a component that scatters the toner and stains the machine, and further causes image fog. As an ingredient, it was considered necessary to actively reduce it.

However, according to the study by the present inventors, it was found that color toner particles of about 5 μm are an essential component for forming a high quality image.

For example, by using a two-component type developer having a color toner and a carrier having a particle size distribution ranging from 0.5 μm to 30 μm, the surface potential on the photoconductor is changed, and a large development potential contrast in which many toner particles are easily developed, To the halftone, further develop the latent image of changing the latent image potential on the photoconductor, up to the latent image of minute dots where only a few toner particles are developed, collect the developed toner particles on the photoconductor, The toner particle size distribution was measured and found to be 8μ.
It has been found that there are many color toner particles of m or less, especially about 5 μm on the latent image of fine dots. That is, when the color toner particles having a particle diameter of about 5 μm are smoothly supplied to the development of the latent image on the photoconductor, the image is faithful to the latent image and does not protrude from the latent image, and an image having truly excellent reproducibility is obtained. You can get it.

When the number of color toner particles having a particle size of 5 μm or less is less than 15% by number, there are few color toner particles effective for high image quality,
In particular, as the toner is used by continuing copying or printing, the effective color toner particle component decreases, the balance of the particle size distribution of the color toner as shown in the present invention deteriorates, and the image quality gradually deteriorates. Come on. If it exceeds 40% by number, color toner particles tend to agglomerate with each other, resulting in toner agglomerates larger than the original particle size, resulting in rough image quality, lower resolution, or edge portion of the latent image. The difference in density between the inside and the inside becomes large, and the image tends to be slightly hollow.

Further, in the color toner of the present invention, 12.7 to 16.0
Particles in the range of μm are 0.1 to 5.0% by volume (preferably 0.2 to
One of the characteristics is that it is 3.0% by volume.

This is related to the necessity of the presence of the color toner particles having a particle size of about 5 μm described above, but the color toner particles having a particle size of 5 μm or less surely have the ability to faithfully reproduce the latent image of the minute dot. Although it has, it is quite highly cohesive,
Therefore, the fluidity of the color toner may be impaired.

The present inventors have described the above-mentioned 2
By adding at least one kind of inorganic oxide, it was attempted to improve the fluidity, but by means of adding an inorganic additive alone,
It was confirmed that the conditions for satisfying all the items such as image density, toner scattering, and fog were extremely narrow. Therefore, the inventors of the present invention further studied the particle size distribution of the toner, and added 15 to 40% by number of color toner having a particle size of 5 μm or less, and 0 to 12.7 to 16.0 μm. .
It was found that the inclusion of 1 to 5.0% by volume solves the problem of fluidity and can achieve high image quality. That is, it is considered that the toner particles in the range of 12.7 to 16.0 μm have appropriately controlled fluidity with respect to the color toner particles of 5 μm or less, and as a result, high density is obtained even when copying or printing is continued. Provides a sharp image with excellent resolution and gradation.

If it is more than 5.0% by volume, the image quality is deteriorated, and more than necessary development, that is, excessive toner overload occurs, resulting in an increase in toner consumption. On the other hand, when the content is less than 0.1% by volume, the fluidity is lowered and the image density is lowered.

Further, regarding the toner particles of 6.35 to 10.1 μm, between the volume% (V), the number% (N) and the volume average particle diameter (v), One of the characteristics is that the color toner of the present invention satisfies the following relationship.

The present inventors, while examining the state of the particle size distribution and the developing characteristics, have found that there is a state of existence of a viscosity distribution that is most suitable for achieving the purpose shown in the above formula.

That is, when the particle size distribution is adjusted by general wind force classification, the fact that the above value is large increases the number of toner particles of about 5 μm that faithfully reproduces a minute dot latent image, and the fact that the above value is small means that the toner particle size is 5 μm. It is understood that some toner particles are shown to decrease.

Therefore, v is in the range of 6 to 10 μm, and
When the above relational expression is further satisfied, good toner fluidity and faithful latent image reproducibility are achieved.

In addition, the color toner particles having a particle size of 16 μm or more are preferably 1.0% by volume or less, more preferably 0.6% by volume or less. In the above, since toner particles of 16 μm or larger are projected on the thin layer surface of the developed toner particles on the photoconductor, the delicate contact state between the photoconductor and the transfer paper via the toner layer is irregular. In particular, it causes fluctuations in transfer conditions, which causes a defective transfer image.

Further, the volume average diameter of the color toner is 6 to 10 μm, preferably 7 to 9 μm, and this value cannot be considered in addition to the above-mentioned constituent elements. If the volume average particle size is less than 6 μm, the problem that the amount of toner adhered on the transfer paper is small and the image density is low is likely to occur in applications such as graphic images having a high image area ratio. It is considered that this is due to the same reason as the reason why the internal density is lowered with respect to the edge portion in the latent image described above. If the volume average particle size exceeds 10 μm, the resolution is not good, and if the use is continued at the beginning of copying, the image quality is likely to deteriorate.

The particle size distribution of the toner can be measured by various methods, but in the present invention, it was measured using a Coulter counter.

That is, the Coulter Counter TA is used as a measuring device.
-Interface (made by Nikkaki) and CX-1 that outputs number distribution and volume distribution using type II (made by Coulter)
A personal computer (manufactured by Canon Inc.) is connected, and a 1% NaCl aqueous solution is prepared using primary sodium chloride as an electrolytic solution. As a measuring method, a surfactant as a dispersant, preferably 0.1 to 5 ml of argylbenzene sulfonate is added to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added.
Add. The electrolytic solution in which the sample is suspended is about 1 ~
Disperse for 3 minutes, then use Coulter Counter TA-
According to the type II, a 100 μ aperture was used as an aperture, the particle size distribution of particles of 2 to 40 μ was measured on the basis of the number, and then the value according to the present invention was obtained.

In the present invention, the color toner having the above-mentioned particle size distribution is a fine powder, and (i) the chargeability of the magnetic particles is the same as that of the toner particles, and the absolute value of the triboelectric charge amount is 50 μC. / g or more, specific surface area S _A by BET method is 80 to 30
0 m ³ / g of hydrophobic inorganic oxide A was added to the toner particles.
% By weight, and (ii) the chargeability with the magnetic particles is opposite to that of the toner particles, and the specific electric resistance is
Spherical resin particles B having a particle size of 0.1 to 1.0 μm in the range of 10 ⁶ to 10 ¹⁴ Ω · cm are added to the colorant-containing resin particles b
% By weight, the content of the hydrophobic inorganic oxide A and the content of the resin particles B satisfy the following formula 0.3 ≦ a + b ≦ 1.5, and the fine powders A and B are It is also characterized in that it adheres to the surface and behaves as a unit during development.

As described above, when the toner having the particle size distribution according to the present invention is used, the development of the toner on the latent image by the fine dots is faithful and the toner adhesion at the end of the latent image is less disturbed.

However, when the toner has a smaller particle size, the Coulomb force and the Van der Waals force acting on the toner become relatively stronger than the gravity and the inertial force, so that the adhesive force between the toners becomes strong and the toner aggregates are formed. It tends to occur.

Further, when the toner has a small particle size, the surface area of the toner particles increases, and the charging tends to become excessive. For example, in the structures of JP-A-54-72054 and JP-A-58-129437, it cannot be said that prevention of toner aggregation and control of charge amount are sufficient.

On the other hand, in the present invention, the chargeability of the magnetic particles is opposite to that of the toner particles, and the specific electric resistance is 10 ⁶ to 1
The problem was solved by adding spherical resin particles in the range of ¹⁴ Ω · cm and having a particle size of 0.1 to 1.0 μm. By adding an appropriate amount of the resin particles of opposite polarity, the charge amount of the toner can be controlled to a suitable level,
Further, the adhesion force due to the charging is weakened, and it becomes difficult to form the toner aggregate.

Further, when the diameter of the toner is reduced, the number of contact points between the toner and the carrier is increased, and carrier spots are likely to occur, or the number of contact points between the toner and toner is increased, and toner blocking is likely to occur. On the other hand, the resin particles having an appropriate size of 0.1 to 1.0 μm serve as a good spacer and exert a good effect. For the toner blocking, it is more effective to use the opposite polarity resin particles having a higher Tg than the toner resin.

Heretofore, there have been some examples of adding resin particles of opposite polarity to toner.For example, Japanese Patent Application Laid-Open No. 54-45135 and Japanese Patent Publication No. 52-32256 disclose colorless resin particles smaller than the toner particle size. Addition has been proposed.

However, in these examples, the toner and the opposite polarity resin particles behave separately and adhere to the toner latent image portion during development, whereas the opposite polarity resin particles adhere to the background portion.
That is, the reverse polarity resin particles act to promote the charging of the toner. However, the present invention is characterized in that the opposite polarity resin particles whose toner particle size is sufficiently small are used, strongly adhered to the toner, and behave integrally. That is, the function of the reverse polarity resin particles is to appropriately suppress the charging of the toner.

Further, conventionally, the opposite polarity resin particles have been used for the purpose of assisting the charging of the magnetic toner which is difficult to have a large amount of charge. On the other hand, the present invention is characterized in that it is used for a non-magnetic toner that tends to be excessively charged.

Further, the specific electric resistance of the reverse polarity resin particles used in the present invention needs to be in the range of 10 ⁶ to 10 ¹⁴ Ω · cm.
If it has a higher resistance than 10 ⁴ Ωcm as with conventional resin,
The charge amount of the reverse polarity resin particles themselves becomes too high, and agglomerates of the reverse polarity resin particles are generated, which fly with the toner in the non-image area and cause fog. Further, if the charge amount of the reverse polarity resin particles is too high, the fluidity of the toner deteriorates and the image density also decreases. On the other hand, when the resistance of the reverse polarity resin particles is lower than 10 ⁶ Ω · cm, the charge amount of the toner particles is reduced particularly under high temperature and high humidity, and as a result, toner scattering and fog occur.

Further, the average particle diameter of the toner of the resin particles used in the present invention is sufficiently smaller and needs to be 0.1 to 1.0 μm. When the average particle size is larger than 1.0 μm, the adhesive force on the toner surface is weakened and a large number of particles are released, so that the effect of the present invention cannot be exhibited.

The particle size of the resin fine particles in the present invention is CAPA-50.
It is the volume average particle diameter measured by 0 type (manufactured by Horiba Ltd.).

On the other hand, the hydrophobic inorganic oxide A functions to supplement the reverse polarity resin particles in terms of imparting chargeability and fluidity. for that reason,
If the BET specific surface area is not more than 80 m ² / g, sufficient function cannot be obtained. More preferably, it is 150 m ² / g or more. Further, similarly, the absolute value of the triboelectric charge amount of the magnetic particles must be 50 μC / g or more to obtain a sufficient function.

In order to make the present invention more effective, the hydrophobic inorganic oxide A and the reverse polarity resin particles B are added to the toner particles such that a weight%, b weight% and 0.3 ≦ a + b are satisfied so as to satisfy the following expressions. ≦ 1.5 Need to be included.

If (a + b) is not within the above range, it becomes difficult to balance the chargeability and the fluidity.

Further, if (a + b)> 1.5, the fixing property as a toner deteriorates, and particularly the transparency of the transparency film deteriorates.

The hydrophobic inorganic oxide used in the present invention has a specific surface area of 80 m ² / g or more, and the absolute value of the triboelectric charge amount with the magnetic particles is 50 μC / g or more negatively charged inorganic oxide. Although it does not matter, it is more preferable to use a treated silica fine powder obtained by subjecting the silica fine powder produced by vapor-phase oxidation of a silicon halogen compound to a hydration treatment. Among the treated silica fine powders, those obtained by treating the silica fine powders so that the hydrophobicity measured by the methanol titration test has a value in the range of 30 to 80 are particularly preferable.

As a method of hydrophobizing, it is imparted by reacting with silica fine powder or chemically treating with an organic silicon compound which physically adsorbs.

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

Examples of such organosilicon compounds include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane,
Trimethylethoxysilane, dimethyldichlorosilane,
Methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α
-Chloroethyltrichlorosilane, ρ-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane,
Triorganosilyl mercaptan, trimethylsilyl mercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethylethoxysilane,
Dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane and 2 to 12 siloxane units per molecule with terminal positions For example, dimethylpolysiloxane containing a hydroxyl group bonded to one Si unit may be used for each unit. These are used alone or as a mixture of two or more.

The treated silica fine powder preferably has a particle size in the range of 0.003 to 0.1 μ. As commercial products, Taranox-500 (Tarco), AEROSIL R-972
(Japan Aroerosil).

The monomer constituting the reverse polarity resin particles used as an additive in the present invention is not particularly limited, but it needs to be selected in consideration of the chargeability of the toner and the like. The following monomers may be mentioned as specific examples of the addition-polymerizable monomer that can be used in the present invention.

That is, styrene and its derivatives, for example, methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene, alkylstyrene such as octylstyrene, fluorostyrene, chlorostyrene. Halogenated styrenes such as bromostyrene, dibromostyrene, iodostyrene, nitrostyrene, acetylstyrene,
Methoxy styrene etc. are mentioned.

Further, addition-polymerizable unsaturated carboxylic acids, that is, addition polymerization such as acrylic acid, methacrylic acid, α-ethylacrylic acid, crotonic acid, α-methylcrotonic acid, α-ethylcrotonic acid, isocrotonic acid, tiglic acid, and ungeric acid. And unsaturated polymerizable aliphatic aliphatic dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid and dihydromuconic acid.

Further, it is also possible to use a metal salt of these carboxylic acids, and this metal salt can be carried out after completion of the polymerization.

Further, esterification products of the addition-polymerizable unsaturated carboxylic acid with an alcohol such as an alkyl alcohol, a halogenated alkyl alcohol, an alkoxyalkyl alcohol, an aralkyl alcohol and an alkenyl alcohol may be mentioned. Then, as specific examples of the alcohol, methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, amyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol,
Alkyl alcohols such as nonyl alcohol, dodecyl alcohol, tetradecyl alcohol and hexadecyl alcohol; halogenated alkyl alcohols obtained by partially halogenating these alkyl alcohols; methoxyethyl alcohol, ethoxyethyl alcohol, ethoxyethoxyethyl alcohol, methoxypropyl alcohol, ethoxy Alkoxyalkyl alcohols such as propyl alcohol; aralkyl alcohols such as benzyl alcohol, phenylethyl alcohol and phenylpropyl alcohol; alkenyl alcohols such as allyl alcohol and crotonyl alcohol.

Amides and nitriles derived from the addition-polymerizable unsaturated carboxylic acid; aliphatic monoolefins such as ethylene, propylene, butene, and isobutylene; vinyl chloride, vinyl bromide, vinyl iodide, 1,2-dichloroethylene. Halogenated aliphatic olefins such as 1,2-dibromoethylene, 1,2-diiodoethylene, isopropenyl chloride, isopropenyl bromide, allyl chloride, allyl bromide, vinylidene chloride, vinyl fluoride, vinylidene fluoride 1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2,4-hexadiene, 3-methyl-2,4-hexadiene Conjugated diene-based aliphatic diolefins such as

Further, vinyl acetates, vinyl ethers; nitrogen-containing vinyl compounds such as vinylcarbazole, vinylipyridine, vinylpyrrolidone and the like can be mentioned.

The fine powder according to the present invention contains one or two of these monomers.
It is possible to use one obtained by polymerizing at least one kind.

The reverse polarity resin particles used in the present invention are not limited to using only one type, and a plurality of types can be used in combination.

The method for producing the opposite polarity resin particles used in the present invention includes a method capable of producing spherical fine particles such as a spray drying method, a suspension polymerization method, an emulsion polymerization method, a soap-free polymerization method, a seed polymerization method, and a mechanical pulverization method. Any method can be used. Among these, as particularly suitable,
Since there is no residual emulsifier, a soap-free polymerization method which does not hinder the chargeability of the toner and has little environmental fluctuation of the specific electric resistance value can be mentioned, but is not particularly limited.

The reverse polarity resin particles may be subjected to particle surface treatment, if necessary. As the surface treatment method, a method of surface-treating a metal such as iron, nickel, cobalt, copper, zinc, gold or silver by a vapor deposition method or a plating method, or a metal oxidation such as the above metal, magnetic material or conductive zinc oxide A method of adsorbing a substance or the like by ion adsorption or external addition, a pigment or a dye, and a triboelectrically chargeable organic compound such as a polymer resin may be supported by coating or external addition.

The molecular weight distribution of the reverse polarity resin particles used in the present invention is required to have a peak molecular weight in the range of 10,000 to 5,000,000, and preferably in the range of 20,000 to 1,000,000.
When the peak molecular weight is larger than 5,000,000, the fixability of the color toner is adversely affected, and when the peak molecular weight is smaller than 10,000,
The magnetic particles are contaminated and the blocking resistance is deteriorated.
The molecular weight distribution of the resin is measured by the following measuring method.

That is, by gel permeation chromatography (GPC), a temperature of 40 ° C., a solvent of tetrohydrofuran,
Inject 300μ of THF with a measurement flow rate of 1.0ml / min and a concentration of 0.1wt%. When measuring the molecular weight of a sample, use a calibration curve prepared from a standard sample of end-dispersed polyethylene.

The reverse polarity resin particles used in the present invention can be used in combination with other additives. For example, zinc stearate as a lubricant, a metal salt of a fatty acid such as aluminum stearate, or a fluorine-containing polymer such as polytetrafluoroethylene, polyvinylidene fluoride, a tetrafluoroethylene-vinylidene fluoride copolymer, or cerium oxide or carbon An abrasive such as silicon or a conductivity-imparting agent such as tin oxide or zinc oxide may be added.

In particular, the addition of a low-charge inorganic oxide such as aluminum oxide or titanium oxide has the function of suppressing the charging of the toner, and the effect of the present invention can be further enhanced. Aluminium oxide and titanium oxide can be obtained with a fine particle size relatively easily by the vapor phase method. Therefore, even if it is used in combination with the present invention, there is no adverse effect such as deterioration of fluidity and it is good.

As the binding substance used for the non-magnetic toner particles used in the present invention, various material resins conventionally known as electrophotographic toner binding resins are used.

For example, polystyrene, styrene-styrene copolymers such as styrene-butadiene copolymers, styrene-acrylic copolymers, polyethylene, ethylene-vinyl acetate copolymers, ethylene-copolymers such as ethylene-vinyl alcohol copolymers. , Phenolic resins, epoxy resins, acrylic phthalate resins, polyamide resins, polyester resins, maleic acid resins and the like. In addition, the manufacturing method and the like of each resin are not particularly limited.

Among these resins, the effect of the present invention is great when a polyester resin having a high negative chargeability is used. That is, while polyester-based resins have excellent fixability and are suitable for color toners, they have a strong negative charging ability and are prone to excessive charging, but when the polyester resin is used in the constitution of the present invention, the harmful effects are improved and excellent. Toner is obtained.

In particular, (In the formula, R is an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2
Is ~ 10. ), A bisphenol derivative or a substitution product represented by the formula (1) is used as a diol component, and a carboxylic acid component composed of a carboxylic acid having a valence of 2 or more or an acid anhydride thereof or a lower alkyl ester thereof (eg, fumaric acid, maleic acid, maleic anhydride, phthalate). An acid, terephthalic acid, trimellitic acid, pyromellitic acid, etc.) is more preferable because it has a sharp melting property.

In particular, in terms of light transmittance in a transparency film, the apparent viscosity at 90 ° C. is 5 × 10 ^{4 to} 5 × 10 ⁶ poise, preferably 7.5 × 10 ⁴ to 2 × 10 ⁶ poise, more preferably 10 ⁵ ~ 10 ⁶ poise, apparent viscosity at 100 ° C is 1
0 ^{4 to} 5 × 10 ⁵ poise, preferably 10 ^{4 to} 3 × 10 ⁵ poise,
More preferably, it is 10 ^{4 to} 2 × 10 ⁵ poises,
A color OHP having good light transmittance can be obtained, and also as a full-color toner, good results can be obtained in fixing property, color mixing property and high temperature offset resistance. The absolute value of the difference between the apparent viscosity P _{1 at} 90 ° C and the apparent viscosity P _{2 at} 100 ° C is 2 × 10 ⁵ <| P ₁ -P ₂
It is particularly preferable that | <4 × 10 ⁶ .

As the colorant, known dyes and pigments such as phthalocyanine blue, induslen blue, peacock blue, permanent red, lake red, rhodamine lake, Hansa yellow, permanent yellow, benzidine yellow and the like can be widely used. The content thereof is 12 parts by weight or less, preferably 0.5 to 9 parts by weight, based on 100 parts by weight of the binder resin so as to sensitively reflect the light transmittance of the OHP film.

A charge control agent may be blended in the toner according to the present invention in order to stabilize the charge characteristics. At this time, a colorless or light-colored household appliance control agent that does not affect the color tone of the toner is preferable.
In the present invention, when a negatively chargeable developer is used, the present invention becomes more effective, and as the negatively charge control agent in that case, for example, a metal complex of alkyl-substituted salicylic acid (for example, a chromium complex of ditert-butylsalicylic acid or And an organometallic complex such as a zinc complex). When the negative charge control agent is blended with the toner, it is added in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 8 parts by weight, based on 100 parts by weight of the binder resin.

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

In the present invention, the surface of the magnetic particles is coated with a resin or the like, and as a method thereof, a coating material such as a resin is dissolved or suspended in a solvent and applied to adhere to the magnetic particles, simply powder. Any conventionally known method such as the method of mixing in step 1 above can be applied. For the stability of the coating layer, it is preferable that the coating material be dissolved in a solvent.

The coating material for the surface of the magnetic particles varies depending on the toner material, but for example, an amino acrylate resin,
Acrylic resins or copolymers of these resins and styrene resins, silicone resins, polyester resins, polytetrafluoroethylene, monochlorotrifluoroethylene polymers, polyvinylidene fluoride, etc. are suitable, but are not necessarily limited to these. .

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

The optimum material for the magnetic particles used in the present invention is 98% or more of Cu-Zn-Fe (composition ratio (5-20): (5-
20): Ferrite particles having a composition of (30 to 80), which are capable of easily smoothing the surface, stabilizing the charge imparting ability, and stabilizing the coat.

The coating amount of the above compound may be appropriately determined so that the charge imparting property of the magnetic particles satisfies the above-mentioned conditions, but in general, the total amount is 0.1 to 30% by weight (preferably 0.3 to 20%) with respect to the magnetic particles of the present invention. % By weight).

It is preferable that the weight average particle diameter of these magnetic particles is 35 to 65 μm, preferably 40 to 60 μm. Furthermore, the weight distribution of 26 μm or less is 2 to 6%, and the weight distribution is 35 μm.
A good image can be maintained between 5 and 43 μm between 5% and 25% and between 74 μm and 2%.

In the present invention, good results are usually obtained when the mixing ratio of the above-mentioned magnetic particles and toner particles is 2.0% by weight to 9% by weight, preferably 3% by weight to 8% by weight, as the toner concentration in the developer. When the toner density is 2.0% or less, the image density is low and it becomes unpractical, and when it is 9% or more, the fog and the scattering in the machine are increased, and the useful life of the developer is shortened.

In order to prepare the toner particles according to the present invention, a thermoplastic resin is sufficiently mixed with a pigment or dye as a colorant, a charge control agent, and other additives, if necessary, with a mixer such as a ball mill, and then heated. Melt, knead and knead using a heat kneader such as a roll, kneader or extruder to disperse or dissolve the pigment or dye in the resin to make them compatible with each other, crush and cool after solidification and strict classification. Then, the toner particles according to the present invention can be obtained.

Each measuring method relating to the characteristic value of the toner used in the present invention will be described below.

(1) Measurement of triboelectric charge amount: FIG. 1 is an explanatory diagram of a triboelectric charge amount measuring device. First, a mixture of particles to be measured and magnetic particles used as a developer is prepared. The mixing ratio is 5 parts by weight for 95 parts by weight of magnetic particles in the case of color toner and toner particles, and 2 parts by weight for 98 parts by weight of magnetic particles in the case of fine powder.

Place the particles to be measured and the magnetic particles in a measuring environment, leave them for 12 hours or more, then put them in a polyethylene bottle, mix them thoroughly, and stir.

Next, put a mixture of particles and magnetic particles whose triboelectric charge is to be measured into a metal measuring container 12 having a conductive screen 13 of 500 mesh at the bottom (the size can be appropriately changed so that magnetic particles do not pass). Put on the lid 14 made of metal. At this time, the total weight of the measuring container 12 is weighed and set as W ₁ (g). next,
In the suction device 11 (at least the portion in contact with the measurement container 12 is an insulator), suction is performed from the suction port 17 and the air volume control valve 16 is adjusted to set the pressure of the vacuum gauge 15 to 250 mmAq. In this state, suction is sufficiently performed (for about 2 minutes) to remove the particles to be measured by suction. The potential of the electrometer 19 at this time is V (volt). Here, 18 is a capacitor, and the capacity is C (μF)
And In addition, weigh the entire measuring container after suction and
₂ (g). This triboelectric charge amount T (μC / g) is calculated by the following equation.

(2) Apparent viscosity measurement: A flow tester CFT-500 type (manufactured by Shimadzu Corporation) is used. Approximately 1.0 to 1.5 g of 60 mesh pass product is weighed. Using a molding machine, this is pressed for 1 minute with a load of 100 kg / cm ² .

This pressurized sample is subjected to flow tester measurement under the following conditions at room temperature and normal humidity (temperature of about 20 to 30 ° C., humidity of 30 to 70% RH) to obtain a humidity-apparent viscosity curve. From the obtained smooth curve, the apparent viscosities at 90 ° C. and 100 ° C. are determined and used as the apparent viscosities with respect to the temperature of the sample.

RATE TEMP 6.0D / M (℃ 1 minute) SET TEMP 70.0DEG (℃) MAX TEMP 200.0DEG INTERVAL 3.0DEG PREHEAT 300.0SEC (sec) LOAD 20.0KGF (kg) DIE (DIA) 1.0MM (mm) DIE (LENG) 1.0MM PLUNGER 1.0CM ² (cm ² ) (3) Measurement of endothermic peak value by DSC: In the present invention, measurement using a differential thermal analysis measurement device (DSC measurement device), DSC-7 (manufactured by Perkin Elmer) To do.

A measurement sample is precisely weighed in an amount of 5 to 20 mg, preferably 10 mg.

Put this in an aluminum pan, use an empty aluminum pan as a reference, in the measurement temperature range 30 ℃ ~ 200 ℃,
The measurement is performed at room temperature and normal humidity at a temperature rising rate of 10 ° C / min.

The temperature at which the endothermic peak of the main peak in the temperature range of 40 to 100 ° C. is obtained in this temperature rising process is taken as the endothermic peak value of the present invention.

(4) Volume resistivity measurement: The volume resistivity in the present invention is measured, for example, by the device shown in FIG. In the figure, 21 is a pedestal. 22 is a pressing means, which is connected to a hand press and has a pressure gauge 23 attached thereto. 24 is a hard glass cell with a diameter of 3.100 cm, in which the sample 25 is placed. 26 is a brass press ram with a diameter of 4.26
6 cm, area 14.2857 cm ² . 27 is a stainless steel push rod having a radius of 0.397 cm and an area of 0.496 cm ² , and the pressure from the press ram 26 is applied to the sample 25. 28 is a brass base, and 29 and 30 are bakelite insulating plates. 31 is an ohmmeter connected to 26 and 28, and 32 is a dial gauge.

In the device shown in Fig. 2, the hand press has a hydraulic pressure of 20 kg / cm ²
When the pressure is applied to the sample, a pressure of 576 kg / cm ² is applied to the sample. The resistance is read from the resistance meter 31, multiplied by the cross-sectional area of the sample, and divided by the height of the sample read from the dial gauge 32 to obtain the volume resistivity.

(5) Hydrophobicity measurement: The methanol titration test is an experimental test for confirming the hydrophobicity of silica fine powder having a hydrophobized surface.

The "methanol titration test" defined in this specification for evaluating the hydrophobicity of the treated silica fine powder is performed as follows. 0.2 g of the fine silica powder to be tested is added to 50 ml of water in an Erlenmeyer flask having a volume of 250 ml. Methanol is titrated from the burette until the total amount of silica is wet. At this time, the solution in the flask is constantly stirred with a magnetic stirrer. The endpoint is observed by suspending the total amount of fine silica powder in the liquid and is expressed as the percentage of methanol in the liquid mixture of methanol and water when the hydrophobicity is reached.

[Examples] The present invention will be described in detail below with reference to examples and drawings. In addition, "%" and "part" show a weight% and a weight part.

Example 1 Polyester resin obtained by condensing propoxylated bisphenol and fumaric acid 100 parts Phthalocyanine pigment 5 parts Di-tertiary butyl salicylic acid chromium complex salt 4 parts After sufficiently premixing with a Henschel mixer,
The mixture was melt-kneaded at least twice with a three-roll mill, cooled, and coarsely pulverized with a hammer mill to a particle size of about 1 to 2 mm. Then, it was pulverized by an air jet pulverizer. Further, the obtained finely pulverized product was classified by a multi-division classifier to obtain a volume average particle size of 8.3 μm, 5 μm or less at 25 number%, 12.7%.
1.6 to 16 μm is 1.6% by volume, 16 μm or more is practically 0, Colorant-containing resin particles (non-magnetic toner particles) are obtained.

The apparent viscosity of these particles is 6.00 × 10 ⁵ poise, 100 at 90 ° C.
It was 1.1 × 10 ⁴ poise at ° C.

The specific surface area by the BET method is 100 parts with respect to 100 parts of the toner particles.
250m ² / g, hydrophobized with hexamethyldisilazane, 0.5 parts silica fine powder with a charge amount of -180μC / g, particle size 0.4μm, specific electric resistance 3 × 10 ¹⁰ Ω
・ Cm, number average molecular weight 75,000, charge amount +150
Cyan toner was externally added together with 0.3 part of acrylic resin particles having a μC / g.

 The endothermic peak of DSC of this toner was 67.2 ° C.

For reference, a classification process using a multi-division classifier is schematically shown in FIG. 3, and a cross-sectional perspective view (stereoscopic view) of the outer multi-division classifier is shown in FIG.

6 parts of this cyan toner was mixed with 94 parts of Cu—Zn—Fe ferrite particles whose surface was coated with a styrene-acrylic acid-diethylhexyl methacrylate copolymer to prepare a developer.

Table 1 shows the charge amount of this toner in a low temperature and low humidity environment (15 ° C., 10% RH) and the charge amount in a high temperature and high humidity environment (32.5 ° C., 85% RH).

Using this developer, a commercially available plain paper copier (CLC-1 Canon) was modified to have a sleeve peripheral speed of 280 mm / sec, and a running test of 30,000 sheets was performed at room temperature and normal humidity (23 ° C, 60 ° C).
% RH), low temperature low humidity (15 ℃, 10% RH), high temperature high humidity (32.5 ℃,
As a result of carrying out in each environment of 85% RH), a high quality image with sufficient image density was obtained in any environment.

Comparative Example 1 As an additive to the toner particles, except that the specific surface area according to the BET method was 220 m ² / g and only 0.8 parts of silica fine powder hydrophobized with dimethyldichlorosilane was used. When the same procedure as in Example 1 was performed, the image density decreased from 1.40 to 1.20 after 1000 sheets under low temperature and low humidity, and the decrease became more remarkable as the copying running progressed.

Comparative Example 2 Among the additives to the toner particles, the reverse polarity resin particles were acrylic having a particle size of 1.5 μm, a specific electric resistance of 5 × 10 ¹⁵ Ω · cm, and a charge amount of +120 μC / g. Resin particle 0.2
When the same procedure as in Example 1 was carried out except that the number of parts was changed, a toner having a strong cohesive property was obtained, and fog occurred in the image. Also, the image density was low in all environments.

Comparative Example 3 Among the additives to the toner particles, the reverse polarity resin particles have a particle size of 0.5 μm, a specific electric resistance of 2 × 10 ¹¹ Ω · cm, and a charge amount of −90 μC / g. The same procedure as in Example 1 was carried out except that the amount of the acrylic resin particles was changed to 0.3 part.
It decreased to 1.15 with 500 cards and did not recover thereafter.

Example 2 100 parts of the toner particles produced in Example 1 had a specific surface area of 160 m ² / g according to the BET method, were hydrophobized with dimethyldichlorosilane, and had a charge amount of −130 μC / g. 0.5 parts of silica fine powder, 0.2 parts of particle size 0.4 μm, specific electric resistance of 7 × 10 ⁹ Ω · cm, and electrification amount of +270 μC / g acrylic resin particles 0.2 parts, BET specific surface area Is 95 m ² / g
And 0.2 part of the alumina fine powder as above were externally added to form a cyan toner.

Image formation was performed using this toner in the same manner as in Example 1, and good results were obtained as in Example 1.

Example 3 Using 3 parts of rhodamine pigment as a pigment in Example 1, volume average particle size: 85 μm 5 μm or less: 17 number% 12.7 to 16 μm: 2.6 volume% 16 μm or more: 0.1 volume% To obtain magenta toner particles.

With respect to 100 parts of the obtained toner particles, the specific surface area by BET method is 230 m ² / g, it is subjected to hydrophobic treatment with hexamethyldisilazane, and the charge amount is −140 μC / g silica fine powder 0.5.
And the particle size is 0.1 μm, and the specific electric resistance is 2 × 10 ¹⁰ Ω
A magenta toner was obtained by externally adding 0.3 parts of acrylic resin particles having a size of cm and a charge amount of +370 μC / g.

The apparent viscosity of this toner is 5.7 × 10 ⁵ at 90 ° C, 5.
The endothermic peak of DSC at 8 × 10 ⁴ poise was 67.8 ℃.

To 6 parts of the above toner, 94 parts of ferrite coated with a styrene-acrylic acid copolymer was mixed to prepare a developer.

When an image was formed using this developer in the same manner as in Example 1, good results were obtained as in Example 1.

[Advantages of the Invention] According to the present invention, an image having high image quality and good color reproducibility can be obtained, and good environmental characteristics can be exhibited even if the environment changes.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a triboelectrification amount measuring device, FIG. 2 is an explanatory diagram of a specific electric resistance measuring device, and FIG. 3 is an explanatory diagram regarding a classification process using a multi-division classifying means. FIG. 4 shows a schematic sectional perspective view of the multi-division classifying means. 51 …… Multi-division classifier, 61 …… Coarse powder 62 …… Powder having a predetermined particle size 63 …… Fine powder, 76 …… Coanda block

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location G03G 9/08 374 372 (72) Inventor Yoshinobu Baba 3-30-2 Shimomaruko, Ota-ku, Tokyo Non-Co. Ltd. (56) Reference JP-A 1-100563 (JP, A) JP-A 1-111361 (JP, A) JP-A 1-101557 (JP, A) JP-A 59-33459 (JP , A) JP-A-1-112253 (JP, A) JP-A 63-125950 (JP, A) JP-A 59-33460 (JP, A) JP-A 61-250658 (JP, A) JP-A 63-4247 (JP, A) JP-A-63-106668 (JP, A) JP-A-54-45135 (JP, A)

Claims (2)

[Claims] 1. A color toner comprising non-magnetic toner particles containing a binder resin and a colorant, and two or more kinds of fine powders.
And a color toner applied to a developer having magnetic particles, wherein the color toner has a volume average diameter of 6 to 10 μm, and
15-40% by number of toner particles having a particle diameter of less than or equal to μm are contained, and 0.1% of toner particles having a particle diameter of 12.7 to 16.0 μm are included.
To 5.0 vol%, toner particles having a particle size of 16 μm or more are contained by 1.0 vol% or less, and toner particles of 6.35 to 10.1 μm are represented by the following formula. And the apparent viscosity of the color toner is in the range of 10 ^{4 to} 5 × 10 ⁵ poise at 100 ° C. and 5 × 10 ^{4 to} 5 × 10 ⁶ poise at 90 ° C. The endothermic peak value is from 58 to 72 ° C., the color toner is, as the fine powder, (i) the chargeability of the magnetic particles is the same as that of the toner particles, and the absolute value of the triboelectric charge amount is Of 50 μC / g or more and a specific surface area S _A by the BET method of 80 to 300 m ² / g is contained in the toner particles in an amount of a% by weight based on the toner particles, and (ii) the magnetic particles Has a polarity opposite to that of the toner particles,
The spherical resin particles B having a specific electric resistance in the range of 10 ⁶ to 10 ¹⁴ Ω · cm and a volume average particle diameter of 0.1 to 1.0 μm are contained in an amount of b% by weight with respect to the toner particles. A color toner characterized in that the content of the inorganic oxide A and the content of the resin particles B satisfy the following formula: 0.3 ≦ a + b ≦ 1.5. 2. The binder resin of the toner particles contains a polyester resin as a main component, the hydrophobic inorganic oxide A contains hydrophobic silica, and the spherical resin particles B contain an acrylic resin as a main component. The color toner according to claim 1, wherein