JPS58208753A - Pressure fixable encapsuled toner - Google Patents

Abstract

PURPOSE:To obtain an encapsulated toner good in pressure fixability onto plain paper, and stable in development and fixing performances after a large number of copying cycles, by coating a core material contg. a pressure fixable component with outer shells made of specified components and having good coatability. CONSTITUTION:The encapsulated toner consists of a core material contg. a pressure fixable component, such as polyethylene, and outer shells for coating the whole or part of the core material. The outer shells contain a vinylidene chloride-acrylonitrile copolymer in 95/5-70/30 ratio, and a styrene type resin, such as polystyrene or styrene-butadiene copolymer. The encapsulated pressure fixable toner thus easily obtained has stable triboelectricity, excellent pressure fixability onto plain paper, and stable development performance and fixability after a large number of copying cycles.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toner used for developing a positive electrostatic latent image in electrophotography or electrostatic printing, and particularly to a capsule toner suitable for pressure fixing.

Conventionally, as an electrophotographic method, US Pat.
Many methods are known, as described in Japanese Patent No. 24748, etc., but generally they utilize photoconductive substances,
An electrical latent image is formed on the photoreceptor by various means, and then the image is developed using toner, and if necessary, after the toner image is transferred to a transfer material such as C paper, heat, pressure, or It can be fixed with solvent vapor or the like to obtain copies.

Various developing methods are also known for visualizing electrical latent images using toner. For example, U.S. Pat. No. 2.874.0
Magnetic brush method described in Specification No. 63, 2.6
A large number of development methods are known, such as the cascade development method described in No. 18.552, the powder cloud method, fur brush development method, and liquid development method described in No. 2.221.776. There is.

Toners used in these developing methods have conventionally been fine powders in which dyes and pigments are dispersed in natural or synthetic resins. Furthermore, a third substance? It is also known to use fine developer powders added for various purposes.

The developed toner image is transferred and fixed onto a transfer material such as paper, if necessary. Methods for fixing toner images include a method in which the toner is heated and melted using a heater or a heated roller, and solidified as a molten layer on the support, and a method in which the toner is completely softened or dissolved in an organic solvent and the resin is melted on the support. A method of fixing toner on a support and a method of fixing toner on a support by applying pressure are known.

Toner materials are selected to suit each fixing method,
Toners used in a particular fusing method generally cannot be used in other fusing methods.

In particular, it is almost impossible to transfer the toner used in the conventionally widely used heat fusion fixing method using a heater to a hot roller constant fixing method, a solvent fixing method, a pressure fixing method, or the like.

Therefore, toners suitable for each fixing method have been researched and developed.
There is.

The method of fixing toner by applying pressure is described in U.S. Patent No. 3.26.
9. Described in No. 626 Mei A1, etc. - CP, energy saving, non-pollution, copying machine Dragon A, *If you put it in, you can make copies without waiting time, there is no risk of burning copies, high-speed fixing. This method has many advantages, such as being able to perform various functions and having a simple fixing device.

However, there are problems such as toner fixability and offset to the pressure roller, and various research and development efforts are being carried out to improve the toner fixability.

For example, Japanese Patent Publication No. 44-9880 describes a pressure fixing toner containing an aliphatic component and a thermoplastic resin, and Japanese Patent Application Publication No. 48-75032 describes a capsule-type pressure fixing toner containing a soft material in the core. JP-A-48-75033 describes a pressure fixing toner using a block copolymer of a tenacious polymer and a soft polymer.

However, it is easy to manufacture, has sufficient pressure fixing performance, does not cause the offset phenomenon to the pressure roller, and has stable developing performance and fixing performance even after repeated use. vinegar,
It is difficult to obtain a practical pressure fixing toner that does not adhere to the carrier, metal sleeve, or photoreceptor surface, and has good storage stability and does not aggregate or form cakes during storage.

For example, pressure fixing toner made of soft material has good pressure fixing properties, but it is difficult to pulverize into toner, and it is easy to cause offset phenomenon to the pressure roller, and it does not transfer to the surface of the Carigo 1 photoreceptor. It is easy to cause adhesion, and there are many problems such as agglomeration and caking during storage.Also, hard resins are easy to make into toner, and toners with excellent chargeability and storage stability can be obtained. It is easy to use, but the pressure fixing properties are extremely poor. This is because many hard resins are harder than the cellulose fibers that make up the paper, so when pressure is applied, they are simply crushed into the white part of the paper and do not get entangled with the fibers.

In addition, in various conventional pressure fixing capsule toners, if a soft material with good pressure fixing properties is used as the core material, the soft material will gradually adhere to the pressure roller as pressure fixing is repeated. This ultimately causes offset and wrapping of the transfer paper, which is undesirable, and if such phenomena are avoided, the pressure fixing performance deteriorates.

Furthermore, recently, a method has been used in which a latent image is developed using a one-component developer that contains magnetic fine particles in the toner and does not use carrier particles, but in this case, the toner binding resin contains magnetic fine particles. The toner is required to have good dispersibility and adhesion with the toner, as well as impact resistance and fluidity, and it is extremely difficult to achieve both this and the pressure fixing performance.

The present invention differs from conventional pressure fixing toner materials in two ways.
9. To provide a pressure fixable capsule toner free from the above-mentioned drawbacks.

In particular, the present invention provides a pressure-fixable capsule toner that is easy to manufacture by using a material with good film properties.

Further, the present invention provides a pressure-fixable capsule toner having stable triboelectric charging properties.

Furthermore, the present invention provides a pressure-fixable capsule toner which has extremely good fixability under pressure on plain paper and whose developing performance and fixing performance are stable even when a large number of copies are made.

Furthermore, the present invention shows good pressure fixing properties even when used as a magnetic toner for one-component thread developer containing magnetic fine particles. The present invention provides capsule toner.

That is, the present invention provides a capsule toner comprising a core material containing a pressure fixing component and an outer shell covering all or a portion of the core material, wherein the outer shell has a weight ratio of vinylidene chloride to acrylonitrile. A pressure-fixable capsule toner, characterized in that it entirely contains a vinylidene chloride-acrylonyl-IJ copolymer having a ratio of 9515 to 70/30 and a styrene resin.

The capsule toner obtained by the present invention has good film properties and is covered with a strong shell, so it is stable even when a soft material is used as the core material, and has good pressure fixability. Moreover, since the triboelectric charging property is good and stable, the developing property is excellent.

The vinylidene chloride-acrylonitrile copolymer used in the present invention has a content ratio (weight ratio) of 9515 to 70/30.
It is necessary that If vinylidenic chloride exceeds this, it will heat up.

This is because a decrease in photostability and a decrease in processability due to solvent insolubilization will result, and if the amount of acrylonitrile exceeds this, a decrease in humidity stability and destabilization of triboelectric charging properties will occur.

Further, a suitable amount of a charge control agent such as a metal-containing dye, nigrosine, etc. conventionally used in toners may be added to the outer shell resin.

Examples of styrenic resins include 1, for example, Boristen, PoIJ.
-P-Chlorstyrene, ho+)hinyltoluene, styrene-butadiene copolymerization, styrene-acrylic acid copolymer, and all conventionally known copolymers can be used.

The content ratio of the vinylidene chloride-acrylonitrile copolymer to the styrene resin varies depending on the vinylidene chloride/acrylonitrile ratio and the type of styrene resin, but is generally preferably from 1/1 to 20/l by weight.

Furthermore, charge control agent fine particles are mixed with the toner (external Tj; S
) can also be used to kill.

The capsule toner of the present invention may contain dyes, pigments, etc., which have been conventionally used as a coloring agent for toners, if necessary, and may contain one or both of the core material and the outer shell. It can be added to.

Furthermore, if it is desired to obtain a magnetic toner, magnetic fine particles may be added to the toner shell. Does it exhibit magnetism as a magnetic substance?
Magnetizable materials such as iron, manganese,
nickel, cobalt.

Conventionally known magnetic materials can be used, such as fine metal powders such as chromium, various ferrites, alloys and compounds of manganese, and other ferromagnetic alloys. These magnetic fine particles may be added to either the core material or the shell material.

A method of manufacturing the capsule toner of the present invention is as follows.

Various known encapsulation techniques can be utilized.

For example, spray drying method, interfacial polymerization method, coacervation method, phase separation method, 1n-situ polymerization method, etc. are described in US Pat. No. 3.338.991 and US Pat. No. 3.326.
The methods described in Japanese Patent Application No. 848, No. 3.502゜582, etc. can be used, and two types of shell materials can be added at the same time, or they can be encapsulated separately and used as a two'N wall. The image obtained with the inventive toner is fixed by passing between a pair of pressure-loaded rollers, but auxiliary heating may be performed. Regarding the pressure fixing device,
No. 4-12797, U.S. Pat. No. 3,269,624:i
No. 3,612,682, No. 3.655.28
No. 2, No. 3,731,358, etc., and the capsule toner of the present invention can be used.

Here, the material to be applied as the pressure fixing component contained in the core material is one that easily gets entangled with the fibers of plain paper under a pressure of about 25 q:q/ζ''nL; .Polyoff copolymers such as polyenane, polypropylene/polytetrafluoroethylene, ethylene-acrylic copolymers, polyethylene vinyl acetate, polyester; polystyrene, styrene-based copolymers such as styrene acrylic, Features: palmitic acid, stearin, higher fatty acid such as lauric acid; polyvinyl pyrrolid; /, epoxy resin, phenol-terpene copolymer, polymethyl silicone, maleic acid-modified phenol resin, methyl bier ether-maleic anhydride Although there are m-copolymers and the like, polyethylene is the best in terms of fixability, releasability, developability, etc.

Examples are shown below. Parts are parts by weight.

[Example 1] ' The above mixture was melt-kneaded and crushed to -C5 to 20 μm, which was used as a core material. These particles lII'g were dispersed in the following solution and a capsule toner was obtained by spray drying.

1 Tetrahydrofuran 31 100 g of the obtained capsule toner was mixed with iron powder IVQ, developed with a Canon copier NP-S000, and linear pressure zslcy/G
When the image was fixed between two pairs of InΩ metal rollers, it was firmly fixed and the image was of good quality. There was no deterioration of the image even after 40,000 images were printed.

[Example 2] After melting and mixing the above mixture, use a jet pulverizer to crush the mixture to 5 to 20μ
This core material was ground into a powder of 0 m/cg, and this core material was then dispersed in a solution having the following composition.

One liter of water was added dropwise to the above dispersion, and a capsule toner was produced by a phase separation method, followed by filtration and drying.

The obtained capsule toner was transferred to a Canon copier NP-12.
0 and was developed, it showed a good image and was firmly fixed at a linear pressure of 251 mm/cm. Also, the image H
There was no change even after setting the resolution to 330,000 pixels.

Applicant: Canon Co., Ltd. Agent Marushima Sacrifice -

Claims (1)

[Claims] In a capsule toner composed of a core material containing a pressure fixing component and an outer shell that covers all or part of the core material, the outer shell has a polymerization ratio of vinylidene chloride to acrylonitrile of 9515 to 70/30. A pressure fixable capsule toner comprising a vinylidene chloride-acrylonitrile copolymer and a styrene resin.