JPH05289398A - Dry toner - Google Patents

Abstract

PURPOSE:To obtain a dry toner excellent in powder flowability, having excellent matching property in a copying machine and capable of forming an image having high picture quality by making a small grain-type toner having a specific particle diameter distribution and to adjusting the compression to a specific degree of compression or below. CONSTITUTION:In the dry toner containing a pulverized coloring particle containing at least a binding resin and a coloring agent as an essential component, the toner particle has 6.0-11.0mum volume average particle diameter, contains <=5mum fine powder and is <=30% in the degree of compression. In this case, the binding resin to be used is a conventionally used single resin or a copolymer having plural components or various materials such as polymer-alloied material. As the coloring agent, for example, quinacridone-based pigment, diazo dye, phthalocyanine-based pigment or magenta, cyan, yellow of monoazo dye or each of other color pigment or pigment of carbon black or the like as a black material are used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improving the matching property of a toner for a dry type electronic copying machine with a copying machine, and more particularly to improving the quality of a low softening point toner applicable to a low temperature fixing copying machine designed as an energy saving specification.

[0002]

2. Description of the Related Art Dry electronic copying machines are mainly designed to meet the needs of users in recent years in consideration of higher image quality. Therefore, in these copying machines, a small particle size dry toner having a volume average particle size of about 11 μm or less is usually required.

However, in order to reduce the particle size of the dry toner, a decrease in fluidity caused by it becomes a problem, and conventionally, as a measure for improving the fluidity, a method mainly using an additive has been proposed.

For example, in Japanese Patent Laid-Open No. 63-74070, the "powder compressibility" of the toner is set to 2 by mixing an additive.
It is disclosed that a high image quality magnetic toner can be obtained by adjusting the content to 5 to 40%.

Further, in JP-A-2-293858, by using a specific carbon black as a colorant and a fluidity improver, the "fluidity index" is set to 5 to 25% to obtain a high quality toner. It is disclosed that it can be obtained.

Apart from these, for example, JP-A-2-2365.
No. 66 discloses that a high-quality toner can be obtained by fixing specific silica fine particles and antistatic particles to colored particles under special conditions. Further, JP-A No. 2-157027 discloses a specific condition. In JP-A 2-300763, the adhesion of fine silica powder as an additive is made "a state without spikes" by a manufacturing method in which the additive is mixed with a specific device. It is disclosed that a high-quality one-component developing method can be provided by the method.

[0007]

Generally, in the case of industrially mass-producing a small particle size toner having a particle size of 11 μm or less by crushing a raw material of the order of several mm, fine particles having a particle size distribution characteristic of about 5 μm or less are not contained. It is technically difficult or costly to control such a control. Therefore, in general, industrially, in consideration of total productivity, mass production is carried out at a level in which the number content of fine particles of 5 μm or less is about 10% or more to obtain an inexpensive small particle size toner with stable quality. You can

However, according to the research conducted by the present inventor, the presence of irregularly-shaped fine particles of about 5 μm or less is a main factor that significantly reduces the fluidity of the toner, and therefore the fluidity is improved by the combined use of additives. The need arises.

Based on the above situation, the object of the present invention is as a small particle size toner having a specific particle size distribution and a compressibility of 30%.
It is an object of the present invention to provide a dry toner which is excellent in fluidity, has good matching properties in a copy machine, and can form a high-quality image by adjusting the following.

[0010]

Means for Solving the Problems As a result of diligent study by the present inventor, even if the volume average particle diameter is 11 μm or less, 5 μm
When the following fine particles are not contained, the matching property in the copy machine hardly poses a problem. On the other hand, in the case where fine particles of about 5 μm or less are contained and the fluidity thereof becomes a problem in terms of matching properties, for example, the above-mentioned JP-A-2-236566, 2-157027,
However, it is not enough to improve the fluidity by simply limiting the conditions for mixing the additives, the shape and the state of the additives like -300763, and the effect can be obtained only by controlling the compressibility to 30% or less. The inventors have found that they can be obtained and have reached the present invention.

That is, the present invention relates to a dry toner containing crushed colored particles containing at least a binder resin and a colorant as main components, and the toner particles have a volume average particle size of 6.0 to 11.0 μm. A dry toner containing fine powder of 5 μm or less and having a compression degree of 30% or less is a gist thereof.

The degree of compression referred to in the present invention is obtained as follows.

(1) The sample on the sieve loosens due to vibration and is loosened in a state of being filled in a cylindrical container. Apparent specific gravity A
Ask for.

(2) While tapping the cylindrical container in the above (1), the sample is dropped in the same manner as in (1) to increase the filling rate, and the apparent apparent specific gravity P is determined.

(3) C = 100 (P-A) / P (%) is taken as the compression degree.

That is, in the present invention, the volume average particle size is 11 μm.
m or less, and the degree of compression of the small particle size dry toner having a particle size distribution containing fine particles of 5 μm or less is 30%.
By specifying the following, the fluidity is improved and the matching property in the copy machine is obtained. However, when the fine particles of 5 μm or less exceed 90%, it is industrially possible to control the compressibility to 30% or less. Because it is difficult to
Fine particles of 5 μm or less are preferably 90% or less. It is more preferably 60% or less.

Further, setting the volume average particle size to less than 6 μm is very difficult in terms of cost in mass production by the pulverization method, and it is also difficult to control fine particles of 5 μm or less to 90% or less. In the present invention, the volume average particle diameter is preferably 6 μm or more.

Further, when the toner is produced by a polymerization method, a spherical toner having substantially uniform particle diameter is usually obtained, and therefore it is not the object of the present invention.

Therefore, in the present invention, the dry toner obtained by pulverization has a volume average particle diameter of 6.0 to 11.0 μm.
The present invention relates to a toner having a particle size distribution such that the particle size is m and contains fine powder of 5 μm or less, and the technical content thereof is basically fine particles of 5 μm or less as disclosed in JP-A-63-74070. Particle size distribution not including
In the case of a magnetic toner of 5 μm, it is essentially different from the one in which the “powder compressibility” corresponding to the degree of compression in the present invention is adjusted to 25 to 40%. Similarly, as disclosed in JP-A-2-293858, the use of carbon black having specific physical properties results in compatibility between the adhesiveness of additives and the image quality. The purpose is different.

In addition to the above-mentioned reduction in particle size, there is an item of energy saving as a design quality required for recent dry type electronic copying machines, and in order to meet this, it is necessary to lower the softening point of dry toner.

In this case, specifically, the softening point T of the toner is
By setting f to 110 ° C. or less, the purpose can be achieved most reliably.

Further, conventional general toners are used for the purpose of avoiding a fusion-bonding phenomenon to a fixing roll when a toner has a low softening point, so-called hot offset, or suppressing copying of a fixed image to a vinyl mat or the like. Similarly to the above, a lubricating low temperature softening substance may be contained. These toners are likely to have some problems with respect to matching properties, but according to the present invention, the toner having a low softening point as described above, particularly the low softening point when a low temperature softening substance having lubricity is contained, is included. A remarkable effect can be obtained in improving the matching property in the toner.

That is, in general, the internal mechanism of the copy machine usually has a stirring section for the purpose of keeping the charging characteristics of the developer uniform, and for feeding the replenishment toner to the developing section. Many are equipped with a transfer means such as a screw. In these agitating parts and the like, particularly when the toner has a low softening point, and the fluidity is low, the particles tend to agglomerate and fuse together, so that the replenishment is ultimately defective,
There is a risk of poor development, poor image quality, and the like. Particularly, in the toner of the present invention having a compression degree of more than 30%, the above-mentioned problems are likely to occur because the toner has the same effect as being compressed by an external force applied for transportation or stirring. However, even with toners having the same composition, the above problems can be effectively avoided and a high-quality image can be stably obtained when the degree of compression is 30% or less according to the present invention.

The softening point Tf in the present invention is 10 k under a load of a flow tester (CFT-500 manufactured by Shimadzu Corporation).
g, die diameter φ0.5 mm, heating rate 3 ° C./min, sample amount 1 g.

The volume average particle size and the number content of fine particles of 5 μm or less were measured with a Coulter Counter Multisizer (manufactured by Coulter Co.) with an electrolyte having a sample suspended together with a surfactant at an aperture diameter of 100 μm. Is the value to be set.

As the binder resin used in the present invention, conventionally known single resins, copolymers of a plurality of components, or various substances such as polymer alloys can be used.

Specifically, for example, polystyrene, styrene, styrene copolymers such as acrylic acid ester copolymers, phenol resins, silicone resins, polyamide resins, acrylic resins, polyester resins, xylene resins. , Vinyl resins, epoxy resins, terpene resins and the like. Examples of the low-lubricity softening substances include waxes such as carnauba wax, microcrystalline wax and paraffin wax, higher fatty acids such as lauric acid and zinc stearate, polyethylene, polypropylene, ethylene / acrylic acid copolymer, ethylene. A substance having a softening point Tf of 105 ° C. or lower is preferably used among vinyl chloride copolymers, polyolefins such as ethylene oxide, olefin copolymers, etc., and the addition amount thereof is the total weight of the dry toner of the present invention. Preferably 1 to 20% by weight, more preferably 1 to
It is preferable to add 10% by weight.

The coloring agent, magnetic powder, and other additives used in the present invention can be appropriately selected from generally known substances and used.

As the colorant, for example, magenta, cyan, yellow such as quinacridone pigment, diazo dye, phthalocyanine pigment, and monoazo dye, and pigments such as carbon black can be used as the black material as well as pigments of each color. Usually, it is added in a proportion of 1 to 25% by weight with respect to the binder resin.

As the magnetic powder, for example, ferromagnets such as iron, cobalt and nickel, as well as alloys and compounds such as magnetite and ferrite can be used, and the ratio is usually 20 to 200% by weight with respect to the binder resin. Used mixed in.

Examples of other additives include fluorine-based resins such as fine powder of vinylidene fluoride, fatty acid metal salts such as zinc stearate, metal oxides such as zinc oxide, and particularly silicon oxides. Aluminum oxides and titanium oxides are preferable in order to make the compression degree 30% or less.

When the toner of the present invention is used as a two-component dry toner, the carrier to be mixed is a powder of glass, iron, ferrite, nickel, zircon, silica or the like having a particle size of about 30 to 1000 μm, Or
A styrene-acrylic acid-based resin, a silicone resin, a polyamide resin, a polyvinylidene fluoride resin, or the like coated with the powder as a core material is used.

In the present invention, when the above-mentioned additive and the colored particles are mixed and processed, a conventionally known container such as a V blender and a ball mill, a container rotating type, a ribbon mixer, a paddle mixer and the like fixed type and a composite type thereof can be used. It can be appropriately selected and used from the inside, but especially Henschel mixer (manufactured by Mitsui Miike Co., Ltd.), hybridizer (manufactured by Nara Machinery) turbo mill (manufactured by Turbo Kogyo Co., Ltd.) Kryptron (manufactured by Kawasaki Heavy Industries Co., Ltd.)
It is possible to preferably use a mixing device including a fixed container that forms at least the outer wall of the above, and a rotating piece that has the same central axis as the fixed container.

[0034]

The present invention will be described in more detail with reference to the following examples.

Examples 1-5 and Comparative Examples 1-3 Examples 1-5 of the dry toner according to the present invention and Comparative Examples 1-
Table 1 shows the composition, particle size distribution, softening point, mixing method, compression degree and the like of No. 3.

[0036]

[Table 1]

The methods for producing dry toners in Examples and Comparative Examples are shown below.

The binder resin and colorant constituting the crushed colored particles A in Table 1 are melted and kneaded in a biaxial extruder, cooled and rolled, coarsely crushed in a hammer mill, and then finely crushed in a jet mill. Grinding was performed. Ultrafine particles were separated from the obtained fine powder by a gas stream classifier to obtain ground colored particles A of the present invention and comparative examples.

Next, each of the additives shown in Table 1 was added and mixed by the following mixing method to obtain a dry toner.

(1) Henschel Mixer 5 kg of the processed product was put into a 20 l container, and the rotary blade was repeatedly operated 10 times in a cycle of a peripheral speed of 45 m / sec for 15 seconds operation / 45 seconds stop.

(2) Kryptron The peripheral speed of the rotating rotor is set to 63 m / sec, and 5 kg of the processed material is charged in the open circuit operation for processing. This operation was repeated 3 times.

(3) Turbular Mixer 1 kg of the processed product was put into a 2 l container and mixed according to a set time. Examples 1 to 5 and Comparative Example 1 in Table 1
~ 3, Ricoh Co., Ltd. dry type electronic copying machine FT-
The results obtained by using a modified 4530 machine and setting the fixing temperature to the values shown in Table 2 and evaluating the image quality and the matching property at the time of continuous copying of 5000 sheets are shown.

[0043]

[Table 2]

[0044]

Since the dry toner of the present invention has a small volume average particle diameter of 6.0 to 11.0 μm, it can be used as a high quality toner. When this small particle size toner is industrially mass-produced by a pulverization method, since it necessarily contains fine particles of 5 μm or less, it is necessary to improve the powder fluidity when the matching property is taken into consideration. However, in the present invention, since the degree of compression is adjusted to 30% or less, it is possible to obtain a dry toner having good matching property with a copy machine and high image quality.

Claims (4)

[Claims] 1. A dry toner containing crushed colored particles containing at least a binder resin and a colorant as main components, wherein the volume average particle diameter of the toner particles is 6.0 to 11.0 μm.
A dry toner containing fine powder of m and 5 μm or less and having a compression degree of 30% or less. 2. The dry toner according to claim 1, which has a softening point Tf of 110 ° C. or lower. 3. A binder resin containing at least one kind of a lubricating low temperature softening substance having a softening point Tf selected from waxes, higher fatty acids, polyolefins and olefin copolymers and having a softening point Tf of 105 ° C. or lower. The dry toner described. 4. The dry toner according to claim 1, containing at least one selected from silicon oxides, aluminum oxides, and titanium oxides as an additive.