JPS606509B2 - Pressure fixing 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 toner that has been subjected to pressure fixing.

Conventionally, as an electrophotographic method, US Pat.
Many methods are known, as described in Japanese Patent No. 3-24748, etc., but in general, a photoconductive material is used to form an electrical latent image on a photoreceptor by various means, and then The latent 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, or the like to obtain a copy.

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

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

As toners used in these developing methods, fine powders in which dyes and pigments are dispersed in natural or synthetic resins have conventionally been used. 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 a method in which the toner is heated and melted using a heater or a heated roller to fuse and solidify it to the support, a method in which the binder resin of the toner is softened or dissolved with an organic solvent and then fixed to the support; A method of fixing toner on a support by applying pressure 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, toner used in the conventionally widely used heat fusion fixing method using a heater is
It is almost impossible to apply this method to color fixing methods, solvent fixing methods, pressure fixing methods, etc. Therefore, toners that pass through each fixing method are being researched and developed. The method of fixing toner by applying pressure is described in U.S. Pat. This method has many advantages, such as the fact that there is no danger of burnt copies, high-speed fixing is possible, and the fixing device is simple.

However, there are problems such as toner fixability and an offset phenomenon to the pressurized low-fu, and various research and development efforts are being carried out to improve the pressurized fixability.

For example, Japanese Patent Publication No. 44-988 describes a pressure fixing toner containing a resin family component and a thermoplastic resin;
-78931, 49-1773, 52-10
No. 8134 and the like discloses a capsule-type pressure fixing toner containing a mineral substance in its core. Also, JP-A-48-
No. 7503 describes a pressure fixing toner using a block polymer of a tenacious polymer and a soft 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 after repeated use, and the carrier, metal sleeve However, a practical pressure-fixed toner with good storage stability that does not adhere to the surface of the photoreceptor and does not aggregate or form cakes during storage has not yet been obtained.

For example, pressure-fixed toner made of soft-purchased substances has good pressure-fixing properties, but it is difficult to finely pulverize into toner, and it is easy to cause an offset phenomenon to the pressure roller, and the carrier "on the surface of the photoreceptor. There are many problems such as adhesion of particles and aggregation and cake formation during storage.

Furthermore, capsule toners are difficult to manufacture, resulting in expensive toners, and it is also difficult to manufacture toners with consistent performance.

Furthermore, since it contains a sensitive substance inside, repeated copying of a large number of copies may cause offset to the pressurized o-foo and problems of adhesion to the carrier and the surface of the photoreceptor. The present invention is completely different from conventional pressure fixing toner materials and provides a pressure fixing toner free from the above-mentioned drawbacks.

The present invention provides a pressure-fixed 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 does not cause offset to the pressurized loaf;
To provide a pressure fixing toner that does not cause adhesion to a carrier, a developing sleeve, or the surface of a photoreceptor.

Further, the present invention provides a pressure fixing toner that does not aggregate or form cakes during use or storage and has excellent fluidity and storage stability.

The present invention resides in a pressure fixing toner containing a mixture of low molecular weight polystyrene and polyvinyl chloride IJ-dene as an active ingredient as a toner binder. The mixing ratio of low molecular weight polystyrene and polyvinyl chloride IJden is 8:2 to 4:6, especially 7
:3 to 5:5 (weight ratio) is preferable. Low molecular weight polystyrene generally has a molecular weight of about 1000-500. If the amount of low molecular weight polystyrene is less than this range, the pressure fixing properties will drop sharply, and if the amount of polyvinylidene chloride is less, offset phenomena and wrapping around the pressure roll will likely occur. Only the above-mentioned mixed resin may be used as the binder for the pressure fixing toner of the present invention, but as long as it does not adversely affect the pressure fixing properties, the chargeability, transferability,
Other resins, waxes, etc. may be mixed for the purpose of improving cleaning properties.

For example, polymers or copolymers of styrene and its substituted products, such as non-low molecular weight polystyrene, poly-P-chlorostyrene, polypynyltoluene, styrene-butadiene copolymer, styrene-acrylic acid copolymer, Vinyl chloride, polyethylene, polyvinyl acetate, polypropylene, polyester resin, acrylic resin, silicone resin,
Epoxy resin, xylene resin, polyamide resin, ionomer resin, furan resin, ketone resin, terben resin,
Phenol-modified terben resin, o-gin, rosin pentaerythritol-ester, natural resin-modified phenolic resin, natural resin-modified maleic acid resin, coumaronindene resin, maleic acid-modified phenolic resin, alicyclic hydrocarbon resin, petroleum resin, phthalic acid Cellulose acetate, carboxymethyl cellulose, methyl vinyl ether-maleic anhydride copolymer, polyvinybutyral, polyvinyl alcohol, polypynylpyrrolidone, cyclized rubber, chlorinated paraffin, wax, fatty acid, etc. can be used. These resins may be used in combination so as not to impair the pressure fixing properties of the fluororesin of the present invention. As the colorant used in the toner of the present invention, all the dyes and pigments conventionally used in electrostatic image toners can be used, and charge control agents can also be used.

Further, when it is desired to obtain a magnetic toner, it is sufficient to mix magnetic fine powder such as magnetite, ferrite, iron powder, etc. Even in this case, the pressure fixability was good. 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.

The pressure applied is generally about 15-30 kg/kg. Regarding the pressure fixing device, Japanese Patent Publication No. 44-12797,
US Pat. No. 3,269,626, US Pat. No. 3,612,682,
It is described in the same No. 3655282, the same No. 3731358, etc. The present invention will be specifically explained below using examples.

Parts in the examples are parts by weight. Example 1 Low molecular weight polystyrene 6 parts Polyvinylidene chloride 4 parts carbon black 5 parts tetrahydrofuran/methyl ethyl ketone (2/3) A 100v Tojo Gonji mixture was placed in a porcelain ball mill and mixed and dispersed overnight, followed by a spray dryer. It was made into toner.

The obtained toner had a particle size of 5 to 10 particles, and the average particle size was 6 to 7 particles. Ten parts of this toner was mixed with 8 ounces of iron powder (trade name EFV250-400, manufactured by Nippon Tetsuko Powder) to prepare a developer. The triboelectric charge amount of this toner is -4.
It was 4Ac/g. The fixing device of a commercially available dry transfer electronic copying machine (product name: NP-5000, manufactured by Canon) is equipped with two upper and lower chrome-plated rigid body lo-fus (total pressure 460 kg).
When copying was carried out using the above-mentioned developer in a copying machine changed to the above, a clear and narrow image without fogging was obtained and the fixation was also good. Furthermore, as a result of making 100,000 copies, copies were obtained that had no grander color compared to the initial image, and no offset wrapping around the pressurized loaf occurred. The result of the fixability test was grade 4. The fixability was evaluated according to the dye fastness test method against friction (JISL0849-1971).

That is, using a friction tester, the toner fixing surface and the white rubbing cloth were rubbed against each other according to a prescribed method (drying test), and the degree of coloring of the white rubbing cloth was compared with the gray scale for contamination. The fixability was evaluated by grade.Example 2
-10 and Comparative Examples The same procedure as in Example 1 was carried out using the resin compositions shown in the table below.

Claims (1)

[Scope of Claims] 1. A pressure fixing toner containing a mixture of low molecular weight polystyrene and polyvinylidene chloride as an active ingredient as a toner binder. 2. The pressure fixing toner according to claim 1, wherein the mixing ratio of low molecular weight polystyrene and polyvinylidene chloride is 8:2 to 4:6 (weight ratio).