JPS6033266B2 - Pressure fixing capsule toner - Google Patents

Description

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

Conventionally, as an electrophotographic method, US Pat.
As described in Japanese Patent No. 124748, a number of methods are known, but generally a photoconductive material is used to form an electrical latent image on a photoreceptor by various means, and then the latent image is The image is developed using toner, and the toner image is transferred to a transfer material such as paper if necessary, and then fixed by heat, pressure, solvent vapor, etc. to obtain a copy.

Various methods are also known for visualizing electrical latent images using toner.

For example, the magnetic brush method described in U.S. Pat. No. 2,874,063, the cascade development method described in U.S. Pat. No. 2,618,552, and the powder cloud method and fur brush development described in U.S. Pat. No. 21,776. law,
Many development methods are known, such as liquid development.

Toners used in these developing methods have conventionally been fine powders in which dyes and pigments are dispersed in natural or synthetic resins. Furthermore, it is also known to use fine developing powder to which a third substance is 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 heating and melting the toner using a heater or heated roller to fuse and solidify it to the support, softening or dissolving the binder resin of the toner with an organic solvent, and fixing it to the support, and applying pressure. A method of fixing toner on a support by using a method is 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 fixing method, a pressure fixing method, or the like. - Therefore, toners suitable for each fixing method are being researched and developed. The method of fixing toner by applying pressure is disclosed in U.S. Patent No. 326962.
It is described in specification No. 6, Japanese Patent Publication No. 46-15876, etc., and is energy saving, non-polluting, allows copying without waiting time (when the copying machine is turned on), and there is no risk of burning copies. This method has many advantages, such as high-speed fixing and a simple fixing device.

However, there are problems such as toner fixability and offset development to pressurized low-foo, and various research and development efforts are being carried out to improve pressure fixing properties.

For example, Japanese Patent Publication No. 44-1988 describes a pressure fixing toner containing an aliphatic component and a thermoplastic resin.
JP-A-48-75032, JP-A-48-78931, JP-A-49-1773, JP-A-52-108134, etc. describe capsule-type pressure fixing toners containing a European substance in the core. Furthermore, JP-A No. 48-75033 describes a pressure fixing toner using a block copolymer of a tenacious polymer and a European polymer.

However, it is easy to manufacture, the pressure fixing performance is sufficient, there is no offset phenomenon to the pressure low-fu, the developing performance and fixing performance are stable even with repeated use, and the carrier, metal sleeve, Does not cause adhesion to the photoreceptor surface,
A practical pressure fixing toner that does not aggregate or cake during storage and has good storage stability has not been obtained.

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 an offset phenomenon to the pressure roller, which causes the carrier and photoreceptor surface to There are many problems such as adhesion of particles and aggregation and cake formation during storage.

Furthermore, hard resins can be easily made into toners, and toners with excellent chargeability and storage stability can be easily obtained, but their pressure fixability is extremely poor.

This is because hard resins are often harder than the cellulose fibers that make up the paper, so when pressure is applied, they are simply crushed inside the paper and do not get tangled 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 European 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 the pressure fixing performance, which is intended to avoid such phenomena, deteriorates.

In this way, those with good pressure fixing properties have poor image surfaces, and those with good image properties have poor fixing properties. Further, in conventional capsule toners, the core material and the outer shell separate due to a slight impact, resulting in poor image quality and short lifespan.

Furthermore, recently, a method has been used in which a static latent image is developed using a one-component developer that contains magnetic fine particles in the toner and does not use carrier particles. The dispersibility and adhesion of the toner as well as the impact resistance and fluidity of the toner are required, and the core material and the outer shell material are separated during development due to the frictional charging between this one-component developer and the development roller. In this case, the outer shell material adheres to the three rollers due to the tribo effect and accumulates, resulting in extremely poor durability, and a practical capsule toner has not yet been obtained.

The object of the present invention is to have good pressure fixing properties, excellent charging properties,
To provide a capsule toner that is impact resistant and has a long life.

Another purpose is to provide a toner that is easy to manufacture and stable during storage, and furthermore, even when it contains magnetic fine particles and is made into a magnetic toner for a one-component developer, it has good developability. An object of the present invention is to provide a capsule toner that has good pressure fixability and can be electrostatically transferred.

The present invention is characterized by a capsule toner comprising a core material containing a pressure fixing component and an outer shell covering the core material, wherein the outer shell contains cyclized rubber and an insulating resin. It is in the fact that

Here, the material used as the pressure fixing component contained in the core material is preferably one that easily entangles with the fibers of plain paper under a linear pressure of about 20k9/c, and examples include the following. Polyolefins such as polyethylene, polypropylene, and polyfluoroethylene. Ethylene-acrylic copolymer.
Polyethylene vinyl acetate. polyester. Styrenic resins such as polystyrene, styrene-butadiene copolymer, and polystyrene acrylic. Higher fatty acids such as palmitic acid, stearic acid, and lauric acid. Polyvinylpyrrolidone. epoxy resin. Phenol-terbene copolymer. polymethyl silicone. Maleic acid modified phenolic resin. Examples include methyl vinyl ether-maleic anhydride copolymer. Among the polyethylenes listed above, USP No. 333
Oxidized polyethylene whose manufacturing method is described in Japanese Patent No. 985 is suitable.

Among these oxidized polyethylenes, those having particularly good pressure fixing properties on plain paper have a density of 0.95 or more, a melt index (MI) of 100 or more, preferably 300 or more,
It had an acid value of 20 or more and a low molecular weight. This density measurement was in accordance with ASTM D1505-5 shore, and the melt index (MI) was measured under the flow rate under condition D on ASTM D1238-5 shore.
It was calculated using the formula MI=0.9211ogF11.039. The cyclized rubber contained in the outer shell is preferably made from natural rubber.

If the thickness of this outer shell is too thin, the developability will be poor, and if it is too thick, the pressure fixing property will be poor.
Preferably, it is 0.8 m to 2 m. In addition, the insulating component to be included in the outer shell together with the cyclized rubber should have a good ability to form a film around the core material when mixed with the cyclized rubber, a good charging property, and a pressure fixing property. Particularly preferred are those that do not inhibit.

For example, polymers or copolymers of styrene or its substituted products, such as polystyrene, poly-P-chlorostyrene, polyvinyltoluene, styrene-butadiene copolymer, styrene-acrylic acid copolymer, styrene-maleic anhydride copolymer, and polyester. Resin, acrylic resin, xylene resin, polyamide resin, ionomer resin, furan resin, ketone resin, terbene resin, phenol-modified terbene resin, rosin, rosin-modified pentaerythritol ester, natural resin-modified phenolic resin, natural resin-modified malein Acid resin, coumaronindene resin, maleic acid-modified phenolic resin, alicyclic hydrocarbon resin, petroleum resin, cellulose acetate phthalate, methyl vinyl ether-maleic anhydride copolymer, starch graft polymer, polyvinyl butyral, polyvinyl alcohol , polyvinylpylene.

Lydone, chlorinated paraffin, wax, fatty acids, etc. can be used alone or in combination. In particular, styrene resin,
Preferred are polyester resins, maleic acid-modified phenolic resins, cellulose acetate phthalate, starch graft polymers, polyvinyl butyral, and the like. The mixing ratio of the cyclized rubber and these insulating components in the outer shell is such that the cyclized rubber is 4% by weight or more, preferably 9% to 4% by weight, and the insulating component is 6% by weight or less. Preferably 1% to 6% by weight of the cyclized rubber, more preferably 85% to 5% by weight of the cyclized rubber, and 15% to 5% by weight of the insulating component.

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

Furthermore, charge control agent fine particles can be mixed (externally added) with the toner and used.

In the capsule toner of the present invention, all dyes, mineral materials, etc. conventionally used as coloring agents for toners can be used, if necessary, and may be added to one or both of the core material and the outer shell.

Furthermore, if it is desired to obtain a magnetic toner, magnetic fine particles may be added to the toner. Does it exhibit magnetism as a magnetic substance?
Any material that can be magnetized may be used, such as fine metal powders such as iron, manganese, nickel, cobalt, and chromium, various ferrites, alloys and compounds of manganese, and other ferromagnetic alloys, which are conventionally known as magnetic materials. Things can be used. These magnetic fine particles may be added to either the core material or the outer shell material, but in the case of obtaining an insulating toner, it is preferable to add them to the core material. The method for manufacturing the capsule toner of the present invention can utilize various known encapsulation techniques.

For example, the spray drying method, interfacial polymerization method, coacervation method, phase separation method, in-situ polymerization method, etc. are described in U.S. Pat. You can use any of the following methods. In these manufacturing methods,
Although the thickness of the outer shell is not necessarily uniform depending on the method and conditions, the purpose of the present application can still be achieved to some extent. The image obtained with the toner of the present invention is fixed by passing between a pair of pressure-loaded rollers, but supplementary heating may be applied.

Regarding the pressure fixing device, Japanese Patent Publication No. 44-12797,
US Pat. No. 3,269,626, US Pat. No. 3,612,682,
The capsule toner of the present invention can be used as described in Japanese Patent Nos. 3,655,282 and 3,731,358.

Here, the fixability is evaluated according to the dye fastness test method against friction (JIS-L0849-1971).
That is, the toner fixing surface and the white rubbing cloth are rubbed against each other using a friction tester according to a prescribed method (drying test), and the degree of coloring of the white rubbing cloth is compared with the gray scale for contamination. The fixability is judged on a scale from 1st grade to 1st grade.
Practical fixability can be obtained at grade 4 or higher, preferably grade 4 or higher. The pressure-fixable capsule toner according to the present invention having the structure described in detail above can withstand impacts of more than 10 kg/c of linear pressure, has a long life, has excellent fluidity, and has a carrier, a developing sleeve, Does not cause adhesion to the photoreceptor surface. Of course, it has excellent pressure fixing properties and does not cause offset to pressure low-fu. Further, the charging property is good, and when mixed with an iron powder carrier and measured, a value of -10 French c/ta or more can be obtained.

Clear, fog-free images can be obtained, development performance and fixation are stable even when making multiple copies, and the product has a long service life. In addition, it does not aggregate or form a cake during storage and has good storage stability.

Furthermore, even when magnetic particles are contained to form a magnetic toner for a one-component developer, the capsule toner has good developability and pressure fixability, and can be electrostatically transferred.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but these are not intended to limit the present invention in any way. Further, all parts in the examples are parts by weight. (Example 1) The above mixture was melted and kneaded using a roll mill at 14,000 for 4 minutes, and then a powder of 5 to 20 fm was obtained using a jet pulverizer (trade name: 100NP, manufactured by Nippon Pneumatic Industries). This was used as the core material.

Next, this core material was dispersed in a solution having the following composition.

This dispersion was dried using a spray dryer (inlet temperature: 150°C, 0°C).
, outlet temperature 100 oo, air flow rate 9/min, two-fluid nozzle type, manufactured by Mitsubishi Kakoki). When this capsule toner was mixed with an iron powder carrier and the amount of triboelectric charge was measured, it was 115 fc.
/It was evening. Next, apply only this magnetic capsule toner to a dry type electronic copying machine (product name: NP-5000, manufactured by Canon).
When I put the image in a developing device and changed the fixing device to Development's Rofu fixing device (two upper and lower chrome-plated rigid rollers with a total pressure of 460 k9), I was able to obtain clear images with good fixing properties and no fog. .

Further, as a durability test of the toner, 10,000 sheets were continuously copied, and compared to the initial image, a copy was obtained that had neither image quality nor fixation quality and had no grand tones. Fixability test result is 4-5
It was class. Toner triboelectric charge after 10,000 copies
It was 3.2 Ac/evening.

(Example 2) A capsule toner was obtained in the same manner as in Example 1 except that carbon black 1 Hakarito was used instead of magnetite.

Add 10 parts of this toner to an iron powder carrier (product name: EFV2).
00/300, manufactured by Nippon Steel Powder) 9 to form a developer, and using this developer, the same procedure as in Example 1 was carried out, and images with good fixability were obtained both at the initial stage and after the durability test. .

The result of the fixability test was grade 5. (Example 3) A one-component developer containing magnetic powder was prepared and tested in the same manner as in Example 1 except that the toner composition was as shown in the following table.

Claims (1)

[Scope of Claims] 1. In a capsule toner comprising a core material having a pressure fixing component and an outer shell covering the core material, the outer shell contains 40% by weight or more of cyclized rubber and 60% by weight of cyclized rubber. A pressure fixable capsule toner characterized by having the following insulating components. 2. The toner according to claim 1, wherein the core substance contains magnetic fine particles. 3. The toner according to claim 1, wherein the pressure fixing component is a polyolefin. 4. The toner according to claim 1, wherein the cyclized rubber is made from natural rubber. 5. The toner according to claim 1, wherein the insulating component is a styrene-butadiene copolymer. 6 A toner image of a capsule toner composed of a core material containing a pressure fixing component and an outer shell containing 40% by weight or more of cyclized rubber and 60% by weight or less of an insulating component is subjected to pressure. A fixing method characterized by fixing by passing between a pair of rollers.