JPS58152258A - Manufacture of wet type toner - Google Patents

Abstract

PURPOSE:To obtain a wet type toner not forming agglomerated cakes, and superior in reproductivity of dots, and solid developing performance, by melting with heat a resin insoluble in solvents at normal temp. and meltable when heated, adding a charge controller, and then cooling them to precipitate the resin in very fine particles. CONSTITUTION:A thermoplastic resin insoluble in a solvent, such as toluene at normal temp. and melted when heated, such as partially saponified ethylene- vinyl acetate copolymer, is melted by heating, and a charge controller, such as cobalt naphthenate, is added to said melt and melted, and then cooled with stirring to precipitate a toner in very fine particles. The charge controller is sufficiently adsorbed to the toner particles. Then, stirring is stopped, the supernatant is removed, an electrically insulating solvent, such as hexane, is added to replace toluene, or the like solvent, and the unadsorbed charge controller is eluted. The wet type toner particles thus obtained do not produce agglomerated cakes for a long period, have superior development performance, and it can form superior image lines having high printing resistance when used for lithographic printing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method C for producing an electrophotographic JII #1 type toner, and more specifically, a method for producing a wet toner in which island flexible 11131 particles are dispersed in an electrically insulating liquid. (Regarding 2, further 6: In detail, the present invention relates to a method for producing a hot toner in which an image formed from the toner can form a line portion with excellent rope resistance for a lithographic printing plate.

A method of forming a line part of a printing plate for a lithographic printing plate using an electrophotographic method is known in the field of light seals C:. This method is generally used on the surface of conductive treated paper - after photoconductive zinc oxide powder is mixed with a binder resin and the zinc oxide master paper is negatively charged and exposed to image light, it is used for electrophotography. This is a method of obtaining a lithographic printing plate by developing and fixing with toner, and then making the non-line areas hydrophilic.

Toner C for electrophotography used in this method is divided into dry toner and wet toner, and the dry toner is a thermoplastic resin powder containing 5 to 15 weight of a coloring agent with a particle size of 10 to 15 μm. Liquid toner consists of an electrically insulating wave body and its C:
It consists of dispersed colorant particles having a particle size α1 to 1#a, and a resin for the purpose of dispersing, fixing, and controlling electricity of the colorant particles is dissolved in the electrically insulating liquid.

When used as a line part of a printing plate for lithographic printing, dry toner contains a large amount of thermoplastic resin, so if it is heat-fixed after development, it will be difficult to adhere to the printing plate substrate (#zinc/binder single layer). It is characterized by good power. However, dry toner has a drawback of poor resolution due to its large particle size.

On the other hand, wet toner has a small particle size of A1 to 1μ, so it has good resolution. Since the adhesion with wallAflA itself is poor and the cohesive force of Sara+:wallAflA itself is small, when used as a printing plate, it is easy to leave traces of the printing plate during printing and second printing, resulting in poor printing durability.

In order to solve the above problem, it is possible to further increase the particle size of the late-forming toner by, for example, mechanically pulverizing and classifying it, but in that case, the background smear increases and the toner itself A new problem arises in that the fluidity of the liquid deteriorates and it becomes easier to aggregate.

The present inventor has developed a liquid toner in which marketable resin particles are dispersed in an electrically insulating liquid as a solution to these drawbacks. However, if such a wet toner is manufactured by mechanically pulverizing thermoplastic beak fat and dispersing it in an insulating liquid, the particle size will not be sufficiently small. There are drawbacks such as a wide particle size distribution and poor resolution, and a low yield for obtaining desired fine particles, which is uneconomical.

Conventionally, the method for manufacturing liquid toner is to mix and disperse coloring materials such as pigments, 11 fats for dispersion, fixation, and charge control, and a solvent in a dispersion mill such as a ball mill, attritor, or three-roll mill. However, this method uses a resin that dissolves in a solvent at room temperature, and dilutes the thermoplastic resin particles with an insulating liquid. However, the present inventors took advantage of the temperature dependence of the solvent solubility of 11 fat, heated it in a thermoplastic resin solvent, and after #I solution, set the precipitation temperature. We have invented a method for producing a wet toner in which fine particles of am are formed by cooling as follows.

However, using a liquid toner in which fine particles of thermoplastic It# are dispersed in an electrically insulating liquid according to the liquid toner manufacturing method e2, a fusion image is formed on an electrophotographic photoreceptor by a well-known liquid developing method. When this was carried out, toner particles adhered only to the periphery of the image where the electric field was strong, and toner particles did not adhere to the center of the solid area where the electric field was weak, resulting in a defective pattern development property.

The present invention is intended to improve the above-mentioned poor developability of the peta portion.

The poor developability in the solid area 1 is caused by the unsatisfactory electric resistance control effect of the toner particles.In order to improve the poor developability in the solid area, 1= is the result of the conventional Wet toner: requires the use of charge control agents such as dyes or metal soaps.

Therefore, a charge control agent such as a brass material or a metal soap was added to the wet toner manufactured by the above-mentioned wet toner manufacturing method (:-1), and the charge control agent was stirred and dispersed. However, on the other hand, the toner
4: The present invention has been achieved by showing that a charge control agent such as a dye or a metal soap is added at the time of 111 lipolysis to have a charge control effect.

That is, the present invention provides a method for producing a wet toner in which a thermoplastic resin is dissolved in a solvent at a temperature exceeding the melting temperature of the resin, and then cooled to a temperature below the precipitation temperature to form fine particles of the resin. It is characterized in that a charge control agent is added at the time of melting, and by having such a structure, it is possible to impart a charge control effect with excellent flat area developability to the liquid toner described in 1 above.

The present invention will be explained in detail below.

In the present invention, it is sufficient that the solubility is temperature-dependent in the presence of an appropriate solvent. More specifically, it is preferable to use a resin that is insoluble in Solvent 1 at room temperature and dissolves when heated. When such fat is used, the liquid toner of the present invention is produced as follows (two steps are carried out).

First, a thermoplastic fat and a charge control agent are added to the solvent, and the solvent is humidified to dissolve the charge control agent and the skin.

At this time, the weight of am in the total sum of sm, 118, and A can control agent to be added may be arbitrary, but in the next step when the melt layer is precipitated, if the skin ratio is too high, Since there is a risk that the particles may come into contact with each other and form a gel-like mass, it is preferable that the number of layers be 1 to 80 times.

Further, the heating conditions may be the lowest temperature required to melt the resin, and it is not preferable to heat the resin more than necessary.

During dissolution, it is preferable to stir according to a conventional method.

Here, the charge control agent can be added at any time before the fat is cooled and turned into fine particles, and in addition to being added before heating and melting the resin as described above, it can also be added during heating and melting of the skin. Alternatively, it may be performed after heating the W fat but before precipitation.

The charge control agents used in the present invention include manganese naphthene, manganese naphthene, zirpnicum naphthene, cobalt naphthenate, iron naphthenate, lead naphthenate, nickel naphthenate, chromium naphthenate, naphthene Zinc acid, naphthene-plated Magne V-cum, manganese ofderate, Ofder-coated V-cum, zirconium octylate, iron ofderate, lead octylate, cobalt-treated ofderate,
Ofder nickel, octyl-plated chromium, zinc ofderate, magne-V cum ofderate, manganese dodecylate, calcium dodecylate, dodecyl sulfur zirconium, iron dodecylate, iron dodecylate, cobalt dodecylate, nickel dodecylate, dodecylate Metal soaps such as chromium, zinc dodecylate, and magnesium dodecylate, alkylbenzene sulfonates such as dodecylpeneinsulfonic acid, Ffv sodium lupeninsulfonate, and barium dodecylpeninsulfonate. Examples include phospholipids such as Ken, seherin, and organic amines such as n-decylamine. can also be used. The amount of the charge control agent to be added may be the minimum amount that exhibits a charge control effect, but it is usually preferable to add the charge control agent in an amount of α01 to 50 weight in the solvent during heating hemolysis.

Next ζ: Melt by heating in a 1W rope, then cool to precipitate skin. At this time, the mixture may be cooled without stirring, but it is preferable to perform stirring or ultrasonic irradiation to disperse the precipitated tree layer particles.

If the cooling is moderate, it may be quenched using dry ice, liquid food, etc., or it may be left to cool naturally.

In this state, the bottle stand used, where the electrical resistance of the solvent used is less than 1010Ω, replaces the jealous medium with a highly electrically insulating liquid. The method is to introduce the Iwanawa medium-high electrically insulating liquid containing the precipitated 1111j11, and after making the solvent SS, the precipitated 41Ii! Precipitating II and removing 1 casing liquid C
;The concentration of the highly electrically insulating liquid can be increased.

Invention 4: Fats that can be used include:
Any material that is frequently glazed and temperature-dependent may be used, such as vinyl chloride, ethylene/vinyl acetate copolymer, polystyrene, barium fat, methacrylic**, ionomer,
Puria Marudo, Polycarbonate F, Polyphenylene Okinai F.

Polysulfone, urea**, polyester and vinegar m
- Partially saponified products of t-lulose, V-recon fat, urethane resin, bot ethylene, alkyd resin, f-polyethylene, ethylenetheacrylic copolymer, and ethylene-vinyl acetate copolymer.

- Ethylene. Am, *, so-called ^-dresin, such as Akuturu Shun ester co-to form, CR resin and its derivatives, petroleum hydrocarbon resin, terpene resin, etc.
I can shout out.

Among these, 1[ma-Ie is true if two or more types are used in combination.

The solvent used here is one that dissolves into haze when heated and does not dissolve at room temperature, or one that dissolves at room temperature and becomes insoluble when cooled, so that the solubility depends on heating. That's fine.

In addition, for solvents that dissolve at room temperature and become insolubilized upon cooling, the resin precipitates and becomes insolubilized at room temperature.
For the lf conversion method that needs to be replaced, the method described above may be followed.

As a highly electrically insulating liquid, 4. ) Aromatic hydrocarbons such as toluene, fluorine compounds, etc. may be used.

In addition, Requirement 1: There is no shame in adding 1 minute of soybean soda to the tree, and the method is usually used, such as heating and immersion in #II pilgrimage in advance.
This may be done by adding hot sea bream to the lIl medium at the time of m#l dissolution during the production process of the present invention.

The above-described method for manufacturing a liquid toner according to the present invention has the following features.

This method is thermoplastic! ! The toner is characterized by its ability to provide superior solid image quality compared to liquid toner dispersed in a solvent.

In addition, in order for metal soap etc. to be effective as a charge control agent, it is necessary to Iwl to the 1lIIllllII of the basket mochi wrinkles to be used, but many *** meetings! The woodcutter.

1wIII of wet toners: 6: The normal paraffin, isoparaffinic hydrocarbons, etc. used do not dissolve or dissolve only slightly, and the desired dispersion and charging effects remain unclear. In the wet toner manufacturing method using hot dispersion, the dispersion medium directly becomes the supporting liquid for the wet F toner, so the charge control agents that can be used are limited in terms of compatibility with the supporting liquid. In the method for producing a liquid toner of the present invention,
The solvent used for heating and dissolving the resin was replaced with another electrically insulating medium S:
It is possible to exchange @↑.

Since the charge control agent is added to the heated and melted resin, there is an advantage that usable charge control agents are not limited by their compatibility with the supported wave.

In addition, since the metal soap dissolved in the #I medium significantly reduces the electrical resistance of the carrier wave, it is desirable that the amount of the charge control agent in the carrier liquid be as small as possible. In order to adsorb C:, charge control in the supporting liquid J
It is desirable that the I1m degree be as high as possible, but the two conflict with each other. However, in the method for manufacturing a wet toner of the present invention, a charge control agent is added when the resin is heated and decomposed, and the #l medium is replaced after granulation. , A great advantage is that after adding a charge control agent during dissolution to ensure sufficient adsorption to toner particles, unnecessary charge control agents that are not involved in adsorption of toner particles can be removed by solvent replacement. The two contradictory conditions can be substantially satisfied.

Hereinafter, examples for explaining the present invention in a more detailed manner will be described. Hereinafter, "section" refers to "Seal 11."

Example 1 A separate flask equipped with a trickle-flow condenser and a stirrer was used.

Pour the upper contents into a separate flask.

Melt the fireflies by heating at about 80℃ for 20 minutes in a water bath, then boil them in ice water while stirring for 10 minutes.
When rapidly cooled to ℃, semi-clear particles were precipitated a *t4
When Chitin 4001 was added to the %RO while stirring continued, the particles became opaque and when stirring was stopped, they precipitated into a wild hawk. The supernatant was removed and n-hex was added repeatedly to replace Li1l medium φ with toluene n-hex11-y. [1: From this, the blue-purple color of cobalt naphthenate in the bath solution decreased and became a colorless solution.

The 12-wet toner obtained in this way had an average particle size of about α5, and had a narrow particle size distribution.

The precipitated toner was easily redispersed by stirring, and even after 6 months of production, the particle size did not change to C:q and no agglomeration and cake formation occurred.

Using F1 wet toner, master vapor 1 was produced at -600V1m. Elefax Q
PL-1) with vacuum contact baking equipment R (manufactured by Dainichi Screen, Type 6-P-F) (751"x,
211111) and then developed.

Good reproducibility of halftone dots of 300 meshes/inch, halftone dot area width of 4 to 9691 was obtained, and Beda A111IA had excellent image quality.
Good quality Ichiga was obtained.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the metal soap (cobalt naphthenate) was removed.
inch, and has a halftone dot coverage rate of 44 to 96, but in the case of a solid image, toner particles are attached only to the periphery of the image, and toner particles are attached to the center of the image. do not,
This resulted in poor development of the peta body, and the thick letters turned into blank letters.

Comparative Example 2 A wet toner was prepared in the same manner as in Example 1 except that the metal soap (cobalt naphthenate) was removed using 1g of 111F, and then the metal soap (naphthene-cobalt) tOW was added. Add and stir.

Example 1 and the same machine 1: As a result of the 1J4 image, there was redeposition of halftone dots at 300 lines/inch and a halftone coverage rate of J~96, but toner particles were attached only to the periphery of the image. One image was obtained in which no toner particles adhered to the solid center φ center, and the solid image quality could not be improved.

Example 2 A separate flask equipped with a continuous flow condenser and a stirring motor was used.

Pour the Jokitaki mixture into a separate flask.

The metal soap (10 parts of cobalt naphthenate) was added while heating and stirring for 20 minutes at about 60°C in a water bath.
Meanwhile, when the mixture was rapidly cooled to 10° C. with ice water, translucent particles were precipitated.

Furthermore, when 400 parts of D-hexane was added to the mixture while stirring, the particles became opaque and when stirring was stopped, they settled at the bottom of the container.The supernatant liquid was removed and n-hexane was added. Toluene in #l medium was repeatedly replaced with n-hexane. By replacing the solution, the blue-purple color of cobalt naphthenate in the solution decreases, making it colorless and transparent. It became a liquid.

When the liquid toner obtained in this manner was used, the results of Example 1 and the same machine were tII.

implementation? 45 wm Example 152, the partially saponified ethylene vinyl acetate copolymer Dudenlan 02270 was replaced with the above ratio**
The same procedure as in F1 Example 1 was carried out, except that mt was used in the mixture mixed with carbon black, and the same results were obtained.

Example 4 Banquet 1 In Example 1, metal soap (cobalt naphthenate)
Similar results were obtained by using the same aircraft as in Example 1, except for using Sinan 1011 instead of .

Implementation #15 except that 10% of octyl zinc was used instead of metal soap (naphthene-cobalt) at l@1lt=
Guest 11 and Issei ζ: Go and get the results of the same aircraft.

Example 6 wjI Example 1 &: Metal soap (cobalt naphthenate)
The experiment was carried out on the same aircraft as in Example 1, except that 10111111 (Doderel Sokobal) was used instead of 1, and the same results as those of the same aircraft were obtained.

Example 1 Example 1C: Metal soap (cobalt naphthenate)
Calcium F-decylbenzenesulfonate instead of 10
The experiment was carried out on the same machine as in Example 1, except that the same amount of water was used, and the same results were obtained.

Claims (1)

[Claims] (1) A wet toner production method in which the toner is melted in a thermoplastic resin melting medium at a temperature exceeding the melting temperature of the fat, and then cooled to below the precipitation temperature to form fine particles. 1 grim
Solution 1: A method for producing a liquid toner, which comprises adding an electrostatic control agent. ) Claim 1i (1) (: where required C:
1. A method for producing a liquid toner, which comprises replacing a cough with an electrically insulating liquid after cooling.