JPS58158650A - Manufacture of electrostatic image developing toner - Google Patents

Abstract

PURPOSE:To obtain a toner having superior characteristics and capable of developing an electrostatic image and forming a good visible image, with a shortened step, by polymerizing a polymerizable component contg. a toner characteristics giving agent uniformly dispersed into it in the presence of an org. titanate coupling agent. CONSTITUTION:An org. titanate coupling agent is used as a surface modifier, and toner additives for giving toner characteristics, such as magnetic material, are surface-treated, and uniformly dispersed or said additives are uniformly dispersed together with the surface modifier, into a polymerizable component to prepare an intermediate material in advance. It is especially effective to use a ball mill in order to disperse said additives uniformly. Said material is suspension-polymerized in an aqueous dispersion contg. a dispersion stabilizer, the polymer particles obtained are filtered, washed with water, and dried after centrifugal separation or without making such separation. When the toner characteristics giving agent is used for surface treatement before dispersion into the polymerizable component in advance, an amt. of surface modifier to be used is >=0.1wt%, preferably, 1wt% of the material to be used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toner for developing an electrostatic charge image formed in an electrostatic printing method, an electrostatic printing method, or an electrostatic recording method, and relates to a manufacturing method thereof. Ru.

Three methods are used to develop an electrostatic image: a liquid development method (hot development method) and a dry development method. The former uses a developer in which pigment and dye 11 are finely dispersed in an insulating solvent, and the latter uses a coloring agent such as carbon black, a magnetic substance, a charge control agent, etc. in a natural or synthetic resin. With special characteristics! This method uses a developing agent containing fine toner powder in which a agent J is dispersed.

The present invention relates to the latter developer (K+ agent), and particularly relates to a fine powder of 1 hener used in the developer.

Conventionally, in the production of 1 to 5 for the dry developer, a polymer component for the purpose of fixing on a transfer material such as a set, a stone colorant, a porcelain bamboo powder, a charge control agent, and other toner characteristic imparting agents are added. 8, heated and kneaded, thoroughly dispersed the adhesive agent (11), crushed the resulting colored resin in a cold 71IIL, and classified it into particles with a target particle size range of 1. Edge - 1 fine powder
Rir. .

However, the methods described above have various drawbacks. Firstly, there is a polymerization reaction device for a polymer that becomes one component of the raw material, a dissolution and kneading device N for dissolving and kneading the polymer component with additives such as a special bamboo polishing agent, a crusher, and a classifier. (, < how many - [ 11 ' in the culm and the manufacturing process - 1 ~ is high
The strip f1 for avoiding uniform dispersion is so delicate that uniformly dispersed 1-boo fine powder cannot be stably obtained. In addition, due to the intense shearing force applied in the crosstalk process, the characteristics of the polymer component (↑1) also occur.Thirdly, in the pulverization process, a fine powder suitable for obtaining clear C-fog-free images is produced. Only particles within the particle size range can be obtained.[Instead of powder, fine powder or coarse powder with a particle size other than the desired particle size is produced as a by-product, and these powders with a particle size other than the desired particle size must be classified and removed. There are disadvantages such as the complexity of the process, and the fact that if only one phosphor is made of powder within the target particle size range, the yield will be very poor, leading to an increase in cost.Fourth, the resulting powder is When crushed, the powder may have various shapes, the fluidity of the fine powder may not be good, or it may be further crushed and made finer by stirring during frictional charging, which may cause fogging of images.

As a means to improve the above-mentioned drawbacks, for example,
No. 51830, Japanese Patent Publication No. 51-14895, Japanese Patent Publication No. 1983
-17737Q, inorganic dispersion stabilizers such as lime carbonate, titanium oxide, white lead, calcium carbonate, calcium phosphate, barium sulfate, zinc white, aluminium oxide, silicon oxide, or methylcellulose Water-soluble materials such as boxymethyl cellulose, polyacrylate, polyvinyl alcohol, gelatin, starch, and glutinous ink
Among the polymerizable components using i-polymer, for example, styrene,
A method has been devised in which colored polymer particles are produced by suspension polymerizing methacrylate-1 in water in the presence of carbon black and other additives having 1-inner properties.

According to this method, spherical colored polymer particles with good fluidity can be obtained relatively easily without performing multi-stage operations such as kneading, crushing, and classification. However, according to this method, it is difficult to uniformly disperse the toner characteristic imparting agent in the resin. Especially 1~su special t! 1. (4) If the additive has poor compatibility or solubility with the polymer suspension or various polymerizable substances, it will remain as a powder and will be dispersed unevenly, making it impossible to obtain the desired properties. For example, - When manufacturing a toner containing a large amount of highly hydrophilic 11t< in an aqueous dispersion medium, the magnetic powder is dispersed in the dispersion medium and uniformly dispersed in the polymer component. difficult to do.

Furthermore, for these reasons, polymer particles with poor dispersibility of the toner characteristic imparting agent have a very wide distribution of particle sizes, and if they are not classified, they will not be used as a product and the quality will deteriorate. The advantage that the manufacturing process is only one step is not taken advantage of (the characteristics of the produced toner are not uniform and it cannot be used as a developer as it is).

The purpose of the present invention is to solve the above-mentioned conventional drawbacks, and in particular, it is an object of the present invention to improve the toner manufacturing method using the above-mentioned suspension polymerization, and to produce toners 1 to 1 for developing d electrostatic images in a shortened process. The purpose is to provide a manufacturing method. More specifically, the object is to provide a method for uniformly dispersing a toner characteristic imparting agent in a polymerizable substance and allowing the polymerization to proceed without impairing the uniformity even under stirring. An object of the present invention is to provide a method that enables uniform dispersion of magnetic material even in a one-component toner containing magnetic powder, which is difficult to uniformly disperse.

That is, the present invention provides an electrostatic image developing method 1 which is characterized in that a toner agent ('I: (ζ1!j) is uniformly dispersed in a polymerizable component and then polymerized in the presence of an organic titanate coupling agent 5 ~No- IjIJ method d2 is provided.

In the following, the present invention will be described in detail. In the present invention, an organic ditanate force-bringing agent described in OrI is used as a surface modifier, and by this, a surface treatment agent such as a magnetic material or the like is preliminarily treated, or Alternatively, prepare a large amount of the monomer property-imparting agent and the surface modifier, which are uniformly dispersed in the polymerization↑1 component. Ball mill dispersion is particularly effective for uniformly dispersing the components. Thereafter, suspension polymerization is carried out in an aqueous dispersion medium [1] mixed with a dispersion stabilizer, and the obtained polymer particles are separated by filtration, washed with water and dried, or centrifuged for 1 minute and then dried. Alternatively, after suspension polymerization, the liquid may be directly spray-dried.

The organic titanium 1-based surface modifier used in the present invention is represented by the following general formula.

-〇- R10Ti +OR2) 3, O 1 R+ 0-Ti-+0CR2)3, 1 -O \ 1-12 c-0 \ (R + O) 4 kings i ・[P (OR2) 201-1]
Furthermore, R1 is a hydrocarbon group having 1 to 3 carbon atoms, and R2 is a long chain or cyclic hydrocarbon group having 8 to 20 carbon atoms or a phosphoric acid ester group.

The amount of the above-mentioned surface modifier to be used is 0.1% or more by weight, preferably 1% by weight of the material to be treated when the toner characteristic imparting agent is surface treated before being dispersed in the polymerizable component. It is better to use the above. As a treatment method, for example, an organic titanium 1-coupling agent is dissolved in a solvent of the same volume or more than that of the treated powder, immersed in the powder, and the solvent is evaporated by gentle heating.

In order to ensure complete adsorption and coating on the powder surface during
Stir. After evaporating the solvent, 100-200℃
Heat treatment is performed for 1 to 2 hours to obtain a surface-treated green body.

Alternatively, the organic titanate coupling agent may be dissolved in a solvent, and the solution may be spray-coated, followed by heat treatment. Of course, the surface treatment agent and the treated powder may be simultaneously dispersed in the IF bonding component, and the proportion used in this case should be 1 to the weight of the treated powder.
0.1 to 5%, preferably 1 to 2%.

As the dispersion stabilizer for suspension polymerization, the conventionally known inorganic dispersants mentioned above are used.
= Effective in stabilizing polymerizable droplets. Also, water soluble v
As the polymer stabilizer, polyvinyl alcohol is preferable for Mj due to its stable quality, and by adjusting the ecology of polyvinyl alcohol, the degree of polymerization, and its concentration in the aqueous solution, it is possible to adjust the particle size. Of course, a water-soluble polymeric substance and an inorganic dispersant in the form of a gel or sol may also be used to increase the monodispersity of the particles. In particular, in order to increase the stability of polymerizable droplets, it is possible to attempt to stabilize the interface using an electric double layer. If 4jf is used with cationic (or anionic) polyvinyl alcohol and an inorganic dispersant that is ionically charged in water (for example, SiO2 has negative polarity in water), polymerization f (the surface of polyvinyl alcohol that covers the material surface) The inorganic dispersant coats the surface efficiently, contributing to synergistic stabilization.

In the present invention, the amount of the inorganic dispersant used is preferably 0.1 to 10%, and in the case of a water-soluble polymer, it is 0.1 to 1% based on the weight of the dispersion medium in which the polymerizable composition is suspended. That's enough.

In addition, in order to disperse and suspend the polymer composition in uniform droplets in a dispersion medium, it is necessary to stir the dispersion liquid with strong shearing force, and for this purpose, a commonly used homomixer or homogenizer is used to 30009- It is sufficient to stir at the rotational speed of r, p, m. However, the particle size remains stable without changing.If the single polymerization groove is carried out at the usual temperature of 55°C to -120°C, it will be possible to suppress the mass transfer (phase transition) of low-boiling components within the system. for,
A row < 1 at the lowest possible temperature will give better results.

Examples of the polymerized cell component used in the present invention include styrene, O-methylstyrene, m-methylstyrene, p-
Preferred examples include styrene 141 suspensions such as methylstyrene, α-methylstyrene, p-edylstyrene, 2,4-dimethylstyrene, and p-[:1]styrene. Other commonly used techniques +'L L
Of course, the ll fi body may also be used.

In the present invention, 1 to toner special bamboo imparting agent means (
Polymerization (suitable thermal properties as a toner in the water component,
It refers to a substance that provides physical properties such as magnetic properties and electrical properties, and among these, as a coloring agent, conventionally known pigments or dyes can be arbitrarily used, such as carbon black. , nigrosine dye, oil black, and others may be used alone or in combination. Further, when magnetic powder is contained in the toner, the magnetic powder itself has an effect as a coloring agent, so it is not necessary to use the above-mentioned coloring agent. In particular, when manufacturing - component toner, magnetic powders include iron, cobalt, nickel, such as magnetite, hematite, and ferrite.
Substances conventionally known as magnetic materials, such as alloys and compounds of manganese, and ferromagnetic alloys thereof, may be used. The normally used magnetic powder should be as thin as possible, preferably 1 μm, in order to improve its dispersibility in the polymerizable component.
In the following, it is preferable that 1-Q contains 10 to 60% by weight.゛On the other hand, as a catalyst for starting the polymerization reaction, 2,2--azobisisobutyronitrile, 2,2--azobis-[2,
4-dimethylvaleronitrile), peroxides such as benzoyl peroxide, lauroyl peroxide, etc. can be used, and the polymerization reaction is carried out under normal pressure, b+
,, < is under high pressure (any method can be used, but the operation is simple. Regular Example 1: 1 to 1 to 0.2 parts by weight of butane-based coupling agent isopropyl to 1 to lyisostearoyl titanate to 30 parts by weight) After dissolving in 20 parts of triiron tetroxide (fine powder with a particle size of 0.11 t) and immersing it in 20 parts by weight, it was placed in a hot bath for 6 hours without stirring.
The solvent was evaporated at 0°C. Thereafter, heat treatment was performed at 110°C for 2 hours to obtain surface-modified iron oxide powder. Even after treatment, the shape of the powder remained the same as before treatment, and it had a black color.

This surface-treated magnetic material was mixed with 40 parts by weight of styrene and 2-
Mix and disperse 1 to 0.3 parts by weight of 2--azobisisobutyroni in a ball mill to obtain a homogeneous liquid with low viscosity;
Polyvinyl alcohol (complete saponification degree 1700)
0.2! 160% by weight aqueous solution was mixed and stirred in Homosixer (Tokushu Kika Kogyo) at 11,000 rpm, p, and m. Even after stirring, the magnetic material was uniformly encapsulated in the droplets, and the droplets had an average diameter of 1211 mm, showing extremely high monodispersity. While stirring, raise the temperature to 80°C.
After light evaporation for 1 hour, the mixture was stirred at low speed in an ordinary flask to allow polymerization to proceed for 7 hours. The obtained polymer was precipitated to 1l1
11. Washing was repeated to elute the polyvinyl alcohol, and the toner was dried to obtain a toner for a one-component developer with an extremely high sphericity and an average size of 11 μm, which uniformly contained magnetic material. Even after drying, the particles did not aggregate with each other, and the fluidity was good. Using this toner, an electrophotographic copying machine for -component developer (Coby F T-4 manufactured by Ricoh)
When the electrostatic charge image was developed and fixed using a vacuum cleaner (700), an image with extremely good contrast was obtained.

Example 2 A one-component [-ner] was produced under the same conditions as in Example 1 except that 1% by weight of isopropyl tridodecylbenzenesulfonyl titanate was used as a butanate coupling agent. A powder of 1 to 1 to 1 was obtained, and the uniform dispersibility of the magnetic material was also high. When these particles were developed and fixed in the same manner as in Example 1, a good image was obtained.

Example 33 IsojIll Building 1 - Liisostair [1 Iriditanate 0.6 parts, triiron tetroxide (fine powder with particle size 0.1μ) 4
0 parts by weight, 40 parts by weight of styrene, 1 part by weight of carbon black, and 0.5 parts by weight of benzoyl peroxide were sufficiently mixed and dispersed in a ball mill. 1η polymerizable dispersion to 0.5
ffiM% polyvinyl alcohol aqueous solution (polymerization degree 17
Completely saponified product of 00) was added to 1 part of 200 weight if, and 2000r, p,
Stirring was performed at a stirring speed of n+.

As a result, iron oxide was uniformly contained in the polymerizable component droplets even after stirring, and no iron oxide was found to diffuse into the aqueous polyvinyl alcohol dispersion medium.

Stir below temperature to 70℃ Tf? After drying and filtration for 45 minutes, the particle size showed an average of 10 to 13μ, and then a normal flask T1
for 7 hours while stirring at 20 Or, p, m
4- The union was completed. The obtained polymer mixture was repeatedly subjected to sedimentation separation, washing, and drying to obtain a one-component developer toner having an average particle size of 11 μm. When this toner was subjected to a copying test in the same manner as in Example 1, clear images with good contrast were obtained.

Example 4 A polymerizable dispersion prepared in the same manner as in Example 3 and having the same composition ratio was mixed with 2% by weight of hydrophilic colloidal silica,
Using cationic polyvinyl alcohol (polymerization degree 2000, saponification degree 90%) 0.5% by weight aqueous solution 180 parts and a homomixer (manufactured by Tokushu Kika Kogyo), 2ooor,
When the liquid was stirred and suspended with P and lIl, highly monodisperse black droplets with a particle size of 8 to 10μ were obtained, and even when observed under a microscope, the droplets did not coalesce with each other and remained for a long time. It was stable. When the polymerization reaction was started by bringing the temperature to 70°C while stirring with the homomixer, the particles were stable, and even after 1 hour of slow stirring in the flask and polymerization proceeding for 6 hours, the particles remained stable. It remained in its initial state. The resulting mixture was filtered and dried to obtain a dispersion P with an average particle size of 9μ.
A one-component developer 1 to 2 with a high concentration of 1 to 1 was used for 15 prints and was subjected to a photocopy test in the same manner as in Example 1, and very clear and good images were obtained.

Comparative Example 1 Triiron tetroxide (0.1 μ) without surface treatment was used and suspended in an aqueous solution of 0.5% polyhinyl alcohol (degree of polymerization 1700, degree of complete saponification) without ball mill dispersion. Turbidity polymerization was carried out. Polymerization 11 The ratio of the dispersion to the dispersion medium and the 1μ polymerization conditions were the same as in Example 1. At that time, while stirring with homomicry (manufactured by Toku-a Kika Kogyo), the magnetic substance was already diffused into the polyvinylalnylene aqueous solution dispersion medium, the polymerizable component became transparent droplets, and the magnetic substance contained It wasn't done. As the polymerization progressed, the magnetic material that had been dispersed in the aqueous dispersion medium aggregated on the surface of the polymer particles, and the resulting small aggregate powder had an amorphous shape. The average particle size is 20.
It had a large diameter of ~.30μ and a very wide viscosity 1α distribution including fine powder. In addition, as in Example 1, copying test 1
When this process was carried out, the obtained image was foggy and unclear.

Comparative Example 2 The composition ratio was
The polymerization conditions were the same as in Example 1, but the magnetic powder was not retained in the polymerizable component, and as in Comparative Example 1,
The obtained powder had an amorphous shape and was composed of agglomerated magnetic material on the resin surface.

The average particle size was 20 to 30μ, the same as in Comparative Example 1, and particles with a wide particle size distribution containing fine powder between the rows were obtained.
When a copying test was conducted in the same manner as above, an image with poor fixing properties and offset properties was obtained.

Patent applicant Ricoh Co., Ltd. Agent: Patent attorney: Hidetake Komatsu 17- =449

Claims (1)

[Claims] In the coexistence of an organic ditaneous i~ coupling agent, it has the characteristics of 1~ner! 1. A method for producing 1 to 3 toner for electrostatic image development, which comprises uniformly dispersing agent J in a polymerizable component and then polymerizing and covering the 4Ni agent.