JPS5821750A - Ferromagnetic particle dispersion type resin carrier and its manufacture - Google Patents

Abstract

PURPOSE:To elongate the life of a developer for magnetic brush development by reducing the weight of the carrier and making the carrier nonsticky to the toner particles. CONSTITUTION:Fine powder of iron or other ferromagnetic material is dispersed in an elastic binding resin such as high-impact polystyrene or polybutadiene as a base material, and they are kneaded, pulverized and classified to form particles equal to those of a conventional iron powder-base carrier in particle size. The surfaces of the particles are made nonsticky to a toner, and a carrier having a weight <=1/4 time that of an iron powder carrier and <=1/2 time that of an oxide carrier of Fe3O4 or the like. By spraying powder of ''Teflon '' dispersed in trichloroethylene or chloroform on kneaded particles as the base material of the carrier in a fluidized bed, the surfaces of the particles are dissolved in the solvent, and ''Teflon '' powder is stuck to the dissolved parts to solidify the parts. The particles are then heat treated to harden the surface layers and to provide elasticity to the interiors in the unhardened state.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention aims to improve the life of the maple developer 01 by providing a non-adhesive structure to the lightweight toner particles of the carrier in a magnetic brush developer. Conventionally, as a way to extend the lifespan of toner O, the carrier base material 01krkKTear 1jl, etc. has been coated with a material that has non-viscous properties against toner particles. However, when iron powder particles are often used as the carrier base material, an agitation OIM shock is applied to the carrier and toner during agitation of the O agglomerate in the Wanrun machine. As a result, the coating layer such as F6aO* is peeled off, and filming occurs due to this. ＃C In translation, the vh resistance is about half the mu of iron, so the effect is somewhat better, but since the base material has less elasticity, there is a possibility that the carrier will be crushed during stirring. However, no matter how much a non-adhesive resin is used to break the surface of a carrier base material made of ferromagnetic oxide such as F@aO*, filling occurs on the broken surface and the developing ability decreases. As mentioned above, while it can be said that conventional carriers are not expected to have a long service life, the present invention is based on the above points, and In order to achieve weight reduction, non-adhesiveness to toner, and long life, we provide a carrier with the following structure: @Th1WC iron or ferromagnetic oxide powder as the base material It is a dispersion of resin such as high impact polystyrene and Ptazine'4 elastic 4III! 11 yen
By mixing iron and other ferromagnetic fine powders into these binder resins, these mixtures are crushed and classified, and the conventionally used iron powder is used as a living material. 'J Neya O grain size particle forming 0 Sara Kl! Select a carrier that is non-adhesive to toner and has elasticity as a base fat, and is less than 1/4 of the iron powder carrier, and 1/2 or less of the oxide carrier such as F@aoa. By doing so, a dramatic improvement in operating life can be achieved.

The shape and particle size of the carrier particles have a large influence on the printing characteristics O. ・Nakaya, which is made up of spherical particles, causes a printing defect called center blanking in solid black printing.
On the one hand, I am confident that I will be able to print on a solution *O good 1. On the other hand, it is possible to print solid black on a carrier made of plate-like or incompletely shaped particles, but on the other hand, it is advantageous because of its high printability. (Furthermore, it requires a large amount of power to drive the developing machine, etc.)
However, in general, the shape of the carrier particle O is classified according to the function of the system in which it is employed. There have been attempts to extract the O% length of both carriers by mixing O, and there have also been attempts to form carrier particle tubes with a rounded and deficient shape, thereby attempting to extract the %'& of both carriers. However, in the case of a mixed carrier, non-uniformity occurs due to the flow of O lumps in the developing machine, resulting in separation of the spherical carrier from the plate-like or irregularly shaped carrier.・From the point 2, it is easy to create a rounded and irregularly shaped carrier with the magnetic particle dispersed carrier according to the present invention. ・A magnetic brush that is a mixture of carrier and toner For the image forming agent, #1 is created by stirring the developer inside #4g1.
A guarding force acts between the toner and the carrier. As a result, the toner softens and forms a spent toner, which reduces the electrostatic properties of other toner particles and makes printing impossible.
In order to completely prevent property deterioration of the developer, a method has traditionally been adopted in which the surface of the carrier is coated with toner Kfl and a highly non-adhesive resin to prevent the generation of spent toner. Strong adhesive 1ll
Tef buckwheat is typically used as k, but this is due to the fact that the iron powder surface and the 011 ring (, easy to peel, external forces, plate-shaped or irregularly shaped carriers, because the particles have 0 association with each other, Effective coating is impossible ・For this reason, it can be said that the use of medium-sized particles is almost limited to spherical particles ◎Furthermore, magnetic brush developer carrier 0 Another characteristic is the magnetic property of carrier 0. It can be said that the larger the saturation magnetization, the stronger the force that statically fixes the developer on the magnetic rail.If this force is weak, it will stick to one layer on the carrier plate, and a certain amount of force will be required. This shows that the magnetic amount of the carrier is 0@@0.

In the combined particles of the bound fat and magnetic powder of the present invention, the particle size, particle shape, and KIIFKJt) )ner? 1. It is possible to make the material non-adhesive and also to control the amount of magnetism as appropriate.

1. Particle size 01IIl141 After freezing and solidifying the mass obtained after kneading at a concentration of 11% liquid,
Grind with a super-centre pulverizer, etc., and classify with a sieve to obtain a particle size of tm. 2. Controlled particle shape When producing spherical carriers, the above-mentioned pulverized particles are pulverized with hot air using a fluid-flow granulator.・When making plate-shaped medium yaya, the mixed mass is sliced and then crushed to obtain 01 Kushima-shaped pieces, which are crushed and classified and used as they are.
3. Non-adhesive high-impact polystyrene and butadiene that burn to the surface O toner have non-adhesive properties to the toner, but to further strengthen this, apply a varnish [1 yen]. It is effective when using thermosetting 1111 as a binder resin, such as 1111, for example, ethylene, ethylene, etc.
Thea-on powder dispersed in B-form is sprayed into the mixed m-particle cryolayer, which is the carrier base material. As a result, the surface of the surface is melted by the additive, and the tenten powder adheres to that part and solidifies. Since the surface layer is hardened and the inside is unhardened O, it is highly elastic.

4. Controlling the amount of magnetism during binding**! 1! If too much magnetic powder is added to the carrier, the carrier's magnetic particle O absorption force will become stronger, but the carrier 11
The material becomes brittle and heavy, and it is natural to miss the target.On the other hand, if the amount of magnetic powder is small, a magnetic brush will not be formed, and the carrier will not form on the magnetic tare. It is necessary to mix the magnetic powder so that it has an appropriate amount of magnetism and density at 0 so ζ, where it stops adhering (magnetically). Now, in one knot, metal magnetic powder and saponification activity with low specific gravity are mixed. Magnetic powder can be used to optimize the amount of magnetism.The physical property values of each material are represented by the symbols shown in the table below. j
[and saturation magnetization, - and - can be approximated by the following equation.

p-kaku (shairo+X・ros 10”-”a 4)p・Y)・
...(1) taxes(""/ 10""/ )
From the two equations shown in ``-=(2)a*J@(1)Y), Xs X*f can be determined so that both I and q have predetermined values.

The carrier of the present invention, in which iron or ferromagnetic material *0 fine powder is uniformly dispersed in the O binding resin, will be described in detail with reference to Examples.

Example 1 Iron powder having a particle size of SOKi m or less is used. Next K11
/1 impact polystyrene (Asahi Dow Styroa 47G) was adopted as 111M,
ng was mixed in, stirred with a Raikai machine, and at the same time evaporated and removed trichlene. As the trichlene O removal progressed,
The fj1 sewing material becomes sticky and has a viscosity of 9 degrees.The #1 trichlene is also removed and the kneaded material becomes hard. After this, the imitation powder was pulverized by ultracentrifugal pulverization at 130°C by fluidized granulation to remove residual trichlene O and change the particle shape to 01111E in this way. /i, 1 consisting of spherical particles
tJ11-Iron powder ofli kneaded material is a lightweight carrier No. 10. Of these O, it is classified to have a particle size of 100 to 150 J.
Using a carrier consisting of m, epoxy toner is 1&,0
1 character life test using developer with 11 m (Drawer 15
With a D printer) 1 line 9, the 100,000 sheet printing grade is the same as the initial O printability at IPI 19
The carrier O is approximately 1/6 of the 90 density + t #i carrier O. Due to this, some developer O is scattered inside the imager, and in printing, some 04'vlJ keeper (with the toner, there is some Example 2 Using the same manufacturing method as Example f%11, but using 1 kg of 1 Jlj410 iron powder to 1 KllK of high-impact polystyrene for Group Iit, the density is usually about O iron carrier O. I
A, but in this Ochu Yariya, sm example 1 m11sO life is shown, and at the same time, a drastic change has been made regarding developer scattering and carryover.
tll) sm Example 3 Same m1011iK as Example 1 or 2, but the composition was polybutadiene (CBR) instead of middle impact polystyrene.
-M or RB-810 made by Japan Synthetic Rubber) pipe, and 1 kgt of iron powder is used for 1 kgk of polybutadiene. l! After making particles of 100 to 150 μm in the same manner as in Example 1,
Printing and life tests were conducted on the developer which was subjected to 0°C 2#SekiO heat treatment and bonded etymo heat curing to form a 9.ζO bonded toner 1]. Get results. In other words, even after 10,000 sheets, a printing value of 1.2 or more was ensured once, and there was no scattering of the carry oval when sanding, and there was almost no change in toner 041 density from the initial value of 15μ91gK to 13jC1g. Example 4 #K performs heat 9-buri with the carrier in Example 3.

Polybutacillin (same as '44 913) 100gK to 100g of Teflon powder 100ml drink solution
gtSt + spray onto the carrier (using the fluidized granulator) 0 In this way, the surface is made into Teflon and the water is removed, 19
The carrier is cured with O-shima salt at 0°C for 2 WI1, and Teflon O %I has a positive charge imparting property. In order to impart special characteristics, it is possible to use toner of about 8μC1g using ordinary carriers. Characteristics superior to those shown by J 3 K were obtained.

Claims (1)

[Scope of Claims] (1) A ferromagnetic material particle dispersion carrier characterized by dispersing iron or ferromagnetic material O particles in the t-girt. Ferromagnetic particle dispersion a described in Patent Codling Ohan@Edition Section 1 characterized by having a layer
i + arrogance I? +3) 1ljl, solvent and iron or ferromagnetic material 0
A step of mixing, stirring and removing the solvent with the particles to form a kneaded product 1 in which iron or ferromagnetic material is dispersed in #resin, and cooling the kneaded product to below the Al coagulation degree of the heating medium and crushing it into single particles. A method for producing a ferromagnetic particle-dispersed math carrier, comprising the steps of forming a fine powder and subjecting the fine powder to a heat treatment plant. (4) A step of classifying the fine powder, in which a solvent mixed with Teflon type IIl resin is blown onto the surface of the fine powder.
A patent characterized by having a ti that forms a marohato.
#tO ferromagnetic material