JPS59127060A - Microcapsule toner - Google Patents

Abstract

PURPOSE:To improve a developing characteristic and pressure fixability by specifying the grain size distribution of the particles of a toner contg. C12-C50 carbon chains used for electrostatic photography, magnetic recording, etc. CONSTITUTION:A microcapsule toner having a core material and a shell covering the core material contains C12-C50 carbon chains therein, the weight of the particles having a particle size of <=5mu diameter is <=5% and the number of the particles of >=30mu diameter is <=5% of the entire part. The long chain compd. having C12-C50 carbon chains includes C12-C50 hydrocarbon, fatty acid and its ester and others, and these materials are mixed with a coloring agent and the mixture is pulverized by a suitable method and is thereafter microcapsuled. A drying method in liquid, phase separating method, etc. are usable as the method for microcapsulation. The toner prepd. by various methods as mentioned above has substantial fixing performance, and is suitable for continuous use of multiple times, preservation for a long period, etc. without sticking and cohering on a copying device, etc. when used in said device, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toner used for electrostatic photography or magnetic recording, and more particularly to a pressure-fixable microcassicle toner that can be easily fixed by pressure.

Conventionally, electrophotographic development methods such as the matrix dark lacquer method, fur brush method, cascade development method, and magnetic brush development method are known, but the toners used in these methods contain dyes in natural or synthetic resins. , colored fine powder in which pigments are dispersed is used. For example, in the magnetic brush development method that is currently in widespread use, a two-component developer is used, which is a mixture of iron powder called a carrier and toner. In the case of such a two-component developer, in order to maintain good development, maintenance and adjustment to prevent carrier contamination, toner concentration fluctuations, etc. are necessary and complicated. A developing method using a one-component developer containing powder has begun to be developed and put into practical use.

If it is desired to retain the developed toner image, an operation called "fixing" is performed. Such fixing methods include a method in which the toner is melted and attached in a heat chamber, a method in which the toner is melted with a heated roller and simultaneously pressed onto the support surface, a method in which the toner is melted and attached using a solvent, and then the toner is melted and attached using a solvent. Methods such as applying a resin solution called a fixer onto the image and fixing it are known, but from the viewpoint of energy saving and non-officiality, the pressure fixing method using a rigid roller 2- is being used. be.

The pressure fixing method requires that there is no danger of burning the copy sheet, that copying can be done without waiting time when the copying machine is turned on, that high-speed fixing is possible, and that the fixing device has a simple structure. There are many advantages such as.

However, while current pressure fusing methods have the above-mentioned major advantages, they also have several significant drawbacks. One is that the pressure for fixing is generally 30 to 40 kg/
A linear pressure of m is required, and in order to apply this much pressure, the fixing device is required to have considerable strength, which is undesirable as it increases the size and weight of the fixing device. Furthermore, it is extremely difficult to uniformly apply such pressure to the paper, resulting in the transfer paper becoming wrinkled or curled. Another drawback is that when such pressure is applied to the image using a roller, the surface of the image is smoothed, causing the image to become glossy and degrading the quality of the image.

In order to overcome these drawbacks, it is necessary to perform fixing at a low fixing pressure, and toners that can be fixed at a low pressure are being actively developed. However, it has excellent fixing performance at low pressure, does not cause offset to the pressure roller, and has stable development and fixing performance even after 9 repeated uses. A practical pressure fixing toner with excellent storage stability that does not cause adhesions, agglomeration or caking during storage has not been obtained.

For example, pressure fixing toner made of a soft material has relatively good pressure fixing properties, but it is difficult to finely pulverize into a toner, tends to cause offset to the pressure roller, and is prone to adhesion, agglomeration, and There are problems such as cake formation.

Furthermore, hard resins are easy to form into toners, and toners with excellent chargeability, storage stability, etc. can be easily obtained, but the pressure fixability is extremely poor.

Therefore, in order to satisfy both the developing characteristics and pressure fixing characteristics, - toner particles are composed of a portion with excellent developing characteristics and a portion with good fixing characteristics, and the developing function and fixing function are separated into each part. The idea is to have it held. As an example of this, a soft material having good pressure fixing properties is used as the core material, and the chargeability is 1. Microcapsule toner cartridges whose shell material is a hard substance with excellent fluidity and storage stability, have traditionally been microcasselle-type toner cartridges with a soft substance or liquid as the core and a hard resin shell. Species have been proposed. For example, microcapsule toners with a soft material as the core as seen in Japanese Patent Publication No. 54-8104, Japanese Patent Publication No. 51-35867, and Japanese Patent Publication No. 51-13
Although there is a soft resin solution core microcapsule toner disclosed in No. 2838, there are many unresolved problems such as insufficient pressure fixing ability and offset, and it has not been put into practical use.

Therefore, an object of the present invention is to provide a pressure-fixable microcapsule toner that has high-performance fixing properties even at low pressure.

Still another object of the present invention is to provide a pressure-fixable microcassette toner that exhibits little change in fixability with respect to pressure.

Still another object of the present invention is to provide a pressure-fixable microcapsule toner that is speed-independent and suitable for high-speed fixing.

Still another object of the present invention is to provide a pressure-fixable microcapsule toner that does not cause offset to a pressure roller and does not cause adhesion to a metal sleeve or the surface of a photoreceptor.

Still another object of the present invention is to provide a pressure fixable microcapsule toner which has stable developing performance and fixing performance even after repeated use and does not cause aggregation or caking during storage.

A feature of the present invention that achieves the above object is that in a microcassicle toner having a core material and an outer shell covering the core material, C4
Particles containing carbon chains of 2 to C5o and having a particle size of 5μ or less have a weight of 5μ or less, and have a diameter of 30μ
The microcapsule toner is characterized in that the total number of particles is 5 or less.

A long chain compound having a carbon chain of C12 to C5o is C1
゜~C5o hydrocarbons, fatty acids, and their processing? These include chills, metal soaps, fatty alcohols, polyhydric alcohols, and their metal salts, chlorides, fluorides, amides, and bisamides. Commercially available products include paraffin wax,
It is sold as microcrystalline wax or amide wax.

These substances are mixed with a coloring agent if necessary, atomized by an appropriate method, and then formed into microcapsules using a shell material. In the above steps, the core material is prepared to have a target particle size distribution, or if necessary, a classification step is introduced in order to obtain the target particle size distribution.

Specifically, the long-chain compounds having C12 to C5o carbon chains are as follows.

(1) Normal and iso-loughin represented by CnH2n+2 (n=12-50) and compounds having some unsaturation therein include C28n -0ctacosane C52n -DotriacontaneC56n -
f (exatoriacontana, squalane C30H50 and squalane 2, 6, 10, 15, 19, 23
Also included are things like hexamethyltetracosane (C3oH6□).

(2) Among fatty acids having a hydrocarbon chain such as those shown in Table 1, saturated straight chain fatty acids (3) and t alcohols and esters can also be used, for example as shown in the following table.

Table 2: Saturated Alcohols (4) Chlorides of the above substances, such as chlorides and graphenes, can also be used.

(5) Amides and bisamides having a C12 to C5o hydrocarbon chain can also be used, for example as shown in the following table.

These products are commercially available singly or as a mixture. Generally, they are known as mother wax, camphor wax, microcrystalline wax, montan wax, ceremin wax, osikelite, carnauba wax, rice wax, Sierra, quawax, Zanur wax, metal soap, amide wax, and lubricant.

Manufacturers and product names include Rough-in Wax (Nippon Oil), Rough-in Wax (Nippon Oil), Micro Wax (Nippon Oil), Micro'locrystalline Wax (Nippon Seiro), and Hoechst Wax (Hoecit).
AG)% Diamond Wax (New Japan Chemical), Suntite (Seiko Chemical), Kunasate (Nippon Oil & Fats), etc.

Typical grades of paraffin wax include those shown in the table below.

Table 4 - Refine wax and microwax Table 5 - Mother rough-in wax (made by Nippon Seisho) Others, such as Hoechst wax OP (partial saponification of montanic acid futax).

Hoechst AG) E (montanic acid ester wax.

Hoechst AG) GL3 (Partially saponified synthetic wax.

Hoechst AG) etc.

Of course, any number of polymeric substances and a combination of some long-chain compounds may be used as required.

Known resins can be used as the shell material of the microcapsule toner of the present invention, such as monopolymers of styrene and its substituted products such as polystyrene, polyp-chlorostyrene, polyvinyltoluene, styrene-p- Chlorstyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-acrylic acid butyl copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-α chlormethacrylate copolymer Methyl acrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer.

Styrene-vinylethyl ether copolymer, styrenic copolymers such as styrene-maleic acid ester copolymers, polymethyl methacrylate, polydityl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, Rosin, modified rosin, terpene resin,
Phenol resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, urea resins, melamine resins, etc. can be used alone or in combination.

Moreover, a known method is applied as a method for forming microcassicles. For example, a spray drive method, an in-liquid drying method, a phase separation method, a 1n-situ polymerization method, etc. can be used, and in order to provide the toner of the present invention with insulation properties and appropriate triboelectric charging characteristics, a multilayer, shell structure is used. It may be provided.

Further, the pressure fixable microcapsule toner of the present invention can contain various dyes and pigments and magnetic powder, and can be contained in either or both of the core material and the shell material.

Furthermore, the toner of the present invention is mixed with carrier particles such as iron powder, glass beads, nickel powder, ferrite powder, etc., if necessary, and used as a developer for electrical latent images. It can also be used in combination with hydrophobic colloidal silica fine powder for the purpose of improving the free-flowing properties of the powder, and abrasive fine particles such as cerium oxide for preventing toner sticking.

Toners in which the core material is a pressure-fixable substance and the surface is further coated with a hard resin have been known in the past, but the toner according to the present invention has significantly improved development characteristics and fixing characteristics over such toners. This toner exhibits excellent continuous copying characteristics and environmental suitability.

In this method for achieving the present invention, after encapsulating the above-mentioned specific substance as a core material, the toner is classified by a classification step, so that the weight of particles with a diameter of at least 5 μm is 5%.
Below, the particles are classified so that the number of particles with a diameter of 30 μm or more is 5 or less.

Conventionally, it has been known to classify and use sitner9.
It is known that classification characteristics have a large effect on toner performance. The inventors of the present invention have specifically studied the relationship between the particle size characteristics of encapsulated toner and the performance of the toner. However, it has been found that it is effective to carry out a classification process so that the weight of particles having a diameter of at least 5 μm or less is 5% or less, and the number of particles with a diameter of 30 μm or more is 5 cm or less. Ta.

By providing a classification step after encapsulation, it becomes possible to particularly improve the classification efficiency, and in particular, it becomes possible to remove minute particles.

In addition, in particular, by providing a classification process after encapsulation, it is important to remove toner particles that have aggregated some particles generated during the encapsulation process and minute particles that are only due to shell substances, in order to put encapsulated toner into practical use. Extremely effective.

As mentioned above, the toner adjusted to the particle size distribution of the present invention by various methods has sufficient fixing performance, and when applied to a copying machine, etc., there is no adhesion and agglomeration to the machine, and it can be used continuously many times.
It is possible to obtain a toner that can be stored for a long time and has stable and uniform performance even under various environmental changes. This power! The reason why the characteristics of the toner are improved by the cell forming process is considered as follows.

When examining the fixing properties of toners that have undergone a capsule process and have a large percentage by weight of particles with a particle size of 2 μm or less in diameter, it was found that the fixing performance deteriorates significantly as the number of such fine particles increases. Admitted. Although the thickness of the capsule toner wall cannot be confirmed because it is not possible to actually measure it, it is thought that the capsule wall is formed with approximately the same thickness regardless of the particle size. If the capsule walls of large particles and small particles are formed with the same thickness, it is thought that there will be a significant difference when comparing the weight ratio with the core material. The shell material is too small compared to the amount of material, the strength is insufficient, and particles with small particle size have too much shell material compared to the core material and are difficult to fix.

Such particles may be mixed in if they are in a very small amount, but problems will occur if the amount increases to some extent. In other words, when the weight of particles of 5 μ or less increases to 5 inches or more, the number of particles with a large amount of shell material increases, resulting in a visibly poor fixation, and when the number of particles of 30 μ or more increases to 5 inches or more, the shell material increases. Since there are many small particles, the mechanical strength is insufficient, and deterioration phenomena such as particle aggregation occur when stored for a long period of time or when used continuously for a long period of time.

The above particle size distribution is measured using various particle size distribution meters. The most preferred measuring device is a device that disperses particles in a conductive liquid and measures the particle diameter based on the difference in the amount of transmitted current depending on the size of the particles, and is a device commercially available as a Coulter counter with fi 0.1. It is measured using saline solution of about %.

The present invention will be described in detail below with reference to Examples.

Example 1 Hiwax 220P (polyethylene wax manufactured by Mikata Petrochemical) - 100 parts by weight Paraffin wax, wax 0 (carbon chain number approximately 26 manufactured by Nippon Seiro Chemical Co., Ltd.)
100 parts by weight Phthalocyanine blue io weight The above materials were mixed well and then melted and kneaded at 120°C. The kneaded material was dispersed in hot water in a molten state and atomized using a high-speed rotating mixer.

The resulting particles were dried to obtain a fine powder. The particles had an average diameter of 11.2μ, 0.3% by weight of particles of 5μ or less, and 2.0% of particles of 30μ or more. These particles were microcoated with polystyrene using the Sgelle dry method to obtain a microcapsule toner. This toner had an average size of 11.5 microns, a weight of 0.4 inches below 5 microns, and a number of 2.2 inches above 30 microns. When 5 parts of this toner was mixed with 50 parts of a 70 μm iron powder carrier and applied to a magnetic sleeve and the electrostatic latent image was developed, a clear image was obtained.

Example 2 Hiwax 200P (polyethylene wax manufactured by Mikata Petrochemical) 100 parts by weight Paraffin wax 155 (manufactured by Nippon Seisho Co., Ltd., carbon chain number approximately 30)
100 parts by weight magnetite
160 parts by weight of the above materials were thoroughly mixed in a blender and then melt-kneaded at 150°C. The kneaded material was allowed to cool naturally, then coarsely pulverized using a cuttani mill, and further finely pulverized using a pulverizer using a jet stream. The above-mentioned finely ground particles were dispersed in a solution of polystyrene in 10-thimethyl ethyl ketone at room temperature and spray-dried. In this way, a micro-encapsulated toner with a shell of 4 listyrene was created, and further classified using a wind classifier to reduce the particle size to 10.
~20μ. The weight of 5μ or less was 0.2%, and the number of 30μ or less was 1.2%. 0.5 wt% of hydrophobic colloidal silica (trade name R972 manufactured by Nippon Aerosil Co., Ltd.) was externally added to this microcapsule toner and applied to a developing device having a magnetic sleeve to develop a positive electrostatic latent image and transfer it to plain paper. It was applied to a fixing machine with a back linear pressure of 10 kg and 7 cm. The image was clear and fully fixed.

Comparative Example 1 Example 1 was carried out except that the classification step after encapsulation was performed. The produced toner had a weight of 6.5% of particles of 5μ or less, and 7 pieces of particles of 30μ or more. The images had insufficient density and were unclear, and white streaks appeared on the images after several images were obtained.

Example 3 Microcrystalline wax (manufactured by Nippon Seisho Co., Ltd.)
20 parts Hoechst wax KSL (Montan acid wax manufactured by Hoechst AG 3-0 parts Magnetite 80 parts The above materials were thoroughly mixed in a blender, then melted and mixed at 150°C, and then heated using a two-fluid nozzle.

It was collected after being sprayed and pulverized. Next, this fine powder was coated with a cystyrene/mauryl resin by a phase separation method to obtain an encapsulated toner. When used in the same manner as in Example 1, the same results were obtained. .

Claims (1)

[Claims] The weight of particles containing C12 to C5o carbon chains and having a particle size of 5μ or less is 5% or less, and the diameter is 3
A microcapsule toner characterized in that the number of particles of 0μ or more is 5% or less of the total.