JPS6230260A - Liquid developing agent for electroophotography - Google Patents

Abstract

PURPOSE:To provide a titled developer having extremely stable electric charge stability by incorporating a compd. having an amino group in the nitrogenous heterocyclic nucleus into highly insulating carrier liquid. CONSTITUTION:This developer contains the compd. having the amino group in the nitrogenous heterocyclic nucleus in the highly insulating carrier liquid. The compd. to be used is preferably expressed by the formula (where A denotes a carbon atom or nitrogen atom, Y denotes a bivalent group, n denotes 0 or 1, R1 and R2 denotes a hydrogen atom or org. group and Z denotes the atomic group necessary for forming the nitrogenous heterocyclic nucleus). The nitrogenous heterocyclic compd. having the amino group to be used acts as an electric charge controlling agent to apply good positive charge to toner particles and the charge stability thereof is extremely high. The charge controlling agent is preferably used at a ratio of about 0.001-0.5pts.wt. by 1,000pts. with carrier liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Industrial Field of Application The present invention relates to a liquid developer for electrophotography,
This article relates to a liquid developer for electrophotography that has excellent positive charge stability.

(B) Prior art and its problems The liquid developer used in the development process of electrostatography is generally one in which toner particles containing VC pigment or dye and resin as main components are dispersed in a highly insulating carrier liquid. It is. Generally, such agglomerate agents do not have sufficient charge properties or lack stability, so 4U4 fatty acids, 4U4 fatty acids, etc. are used as charge control agents.
Attempts have been made to add fatty acids, gold Js4 salts such as alkylbenzenesulfonic acids, alkylphosphoric acids, naphthenic acids, and various nonionic surfactants.

Despite this, conventional liquid developing agents have insufficient charging characteristics and cannot obtain sufficient image density unless they are used for high-potential a-images. It contained defects such as a gradual change in the load 11t characteristics, a decrease in image quality, and the occurrence of capri.

(0) Object of the Invention An object of the present invention is to provide a liquid developer for electrophotography that improves the above-mentioned drawbacks of conventional liquid developers.

(D> Structure of the Invention The object of the present invention has been achieved by a liquid developer for electrophotography, which is characterized in that a high linearity carrier liquid contains a compound having an amino group in the complex complex layer.

The above compound used in the present invention is preferably represented by the following general formula (I).

General formula (1) Re2 (wherein, human is a carbon atom or nitrogen atom, Y is a divalent group, n
is O or 1, R2 and 几 are hydrogen atoms or organic groups, Z
represents the atomic group necessary to form a nitrogen-containing heterocyclic nucleus. ) Specific examples are shown below.

-N (15) NH’ N.H.

(16) H The nitrogen-containing heterocyclic compound having an amino group used in the present invention functions as a charge fT control agent that imparts good positive charge to toner particles, and its charge stability is extremely poor.

In order to obtain a charge control agent that provides a positive charge of 1 iL, there is a method in which the charge control agent is present in the carrier liquid in the form of a salt with an acid such as a carboxylic acid. That is, it is not limited to carboxylates. Furthermore, the compound of general formula (I) is insoluble or poorly soluble in the carrier liquid, and can be added to the carrier liquid in a solution of an organic solvent such as methanol, ethanol, dimethylformamide, butyl acetate, toluene, or xylene. It is preferable to add it as At that time, it is preferable to use it in the presence of carboxylic acid or the like. The acid used to make salt is
Preferably, the compound has a higher solubility in the carrier liquid than the compound of general formula (I).

For example, aromatic acids such as benzoic acid, cinnamic acid, propionic acid, butyric acid, valeric acid, caproic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, cerotic acid, oleic acid, sorbic acid. Various types of saturated or unsaturated fatty acids such as linoleic acid, linolenic acid, and linoleic acid can be used. strengthen. Furthermore, the acid to be made into a salt is an addition-polymerizable carboxylic acid such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, or fumaric acid, and the following formula:
It is also possible to use a polymeric acid soluble in a carrier liquid obtained by copolymerizing a heptamer as shown by X 0H,=O-Y. In addition, such a polymeric acid is used in toner resin particles, rather than being added to the carrier liquid by carving a weir in advance, and the compound of the general formula (I) is added to the carrier liquid. It may be in the form of

As a method for producing a liquid developer using the charge control agent according to the present invention, various methods can be used.
For example, a colorant, a resin, and a charge control agent are mixed and dispersed in a carrier liquid such as a petroleum-based aliphatic hydrocarbon, aromatic hydrocarbon, or halogenated aliphatic hydrocarbon using a dispersion machine such as an attritor or a ball mill. A method of diluting the concentrated toner obtained by diluting the concentrated toner with a low dielectric constant, highly insulating carrier liquid, a method of obtaining toner particles by dropping a concentrate of a colorant, a resin, and a charge control agent into the carrier liquid, and a method of obtaining toner particles with a low dielectric constant and a high dielectric carrier liquid. There is a method in which a colorant and a charge control agent are added after obtaining toner particles by polymerizing monomers in a highly insulating carrier liquid.

The carrier liquid used in the present invention has a low g'rIL rate and high electrical insulation properties, such as normal paraffinic hydrocarbons, isoparaffinic hydrocarbons, alicyclic hydrocarbons,
Examples include aromatic hydrocarbons, halogenated aliphatic hydrocarbons, etc., but imparaffinic hydrocarbons are preferred, such as Shell Silua 1 (Shell Oil Table), Isopar G and Isopar H, Isopar K and Isopar L (Esso Oil M ) Ivy Solvent (Source: Sekijuku Co., Ltd.) 4 can be used. As toner particles, pigments or dyes such as carbon black are mixed with resin, such as alkyd resin, acrylic resin, rosin, rubber, styrene-acrylic ester copolymer, etc. Covered, or JP-A-53-123138, JP-A-57-129450, JP-A-59-83174, JP-A-59
-212851, etc., oil-soluble azo dyes such as oil black and oil red, basic azo dyes such as Bismarck brown and chrysoidine, and acidic dyes such as wool black, amide black green, and blue black HF. Azo dyes, direct dyes such as Direct Day Black E1 Congo Red, anthraquinone dyes such as Sutan Violet and Acid Blue,
Those colored with colorants such as carbonium dyes such as auramine, malachite green, crystal violet, and Victoria blue, rhodamine dyes such as rhodamine B, and quinone imine dyes such as safranin, nigrosine, and methylene blue can be used.

The charge control agent according to the present invention described above has a carrier liquid of 1000
It is preferable to use 0.001 to 0.5 parts by weight based on the weight part.

Hereinafter, the present invention will be explained in detail with reference to Examples.0 (E) Examples Example 1 [Comparative developer] A 7.c1 flask equipped with a stirrer, a thermometer and a nitrogen inlet tube was made of isoparaffinic hydrocarbons. Add Ivy Solvent (sourced from Petroleum) sooy, 1 oz of lauryl methacrylate, and 5 g of methacrylic acid, and add FIFO (benzoyl peroxide) lII as a polymerization initiator.
Polymerization was carried out for 5 hours on a 5°C water bath to obtain a polymer solution.

Thereafter, 100 I of the product solution was taken and transferred to a 1-well flask equipped with a stirrer, a thermometer, a dropping funnel and a nitrogen inlet tube, and 300 I of Ampy Solvent was added thereto at 70°C.
An insoluble copolymer was obtained from a dropping funnel on a water bath using 100 II vinyl acetate, 10 g N-vinylpyrrolidone and 5 I methyl acrylate (T#3°C).
and polymerization initiator AIBN (azobisisoputiloni)
A mixture of IJl)l' was added dropwise over a period of 3 hours.

After that, after roughly heating at 71a for 3 hours in a nitrogen atmosphere,
Cooled to room temperature. The product was a white emulsion of a composite resin dispersion with extremely excellent dispersion stability.0 Next, this emulsion was treated with Oil Black HB.
85.9 to xylene 20. The solution/& dissolved in F? !
, it was on the verge of collapse. Further, 0.55"i of aluminum stearate was added as a charge XtflJ agent, and the mixture was diluted 50 times in Ivy solvent to prepare a toner solution.

The obtained toner was a positively charged toner exhibiting good dispersion stability, and as a result of electron microphotography, the particles were 0.2 μm in size and had a moderate distribution.

[Special iron agent B]

Comparative Toner #1 was prepared in the same manner except that the load control agent was replaced with steverite rosin aluminum m0.59.
It was set as d.

[Comparative Developer C] Comparative Developer 1 A toner solution was prepared in the same manner except that the charge control agent contained in the developer was replaced with 1 g of lauryl aminobalmitate.

[Comparative developer]

A toner solution was prepared in the same manner except that the charge control agent in the comparative developer was replaced with 0.51% of a hemi-docosanylamidate of diimbutylene-maleic acid co-compound. [Invention Embodiment 1] Comparative developer A toner solution was prepared in the same manner except that the charge control agent A was added as a xylene solution of the exemplary compound (511,9 and 3I stearic acid).

These toners were used as a liquid developer for a zinc oxide electrophotographic offset master in a plate making machine EP-11 (Mitsubishi Paper Industries). In order to investigate the charge stability of toner,
Table 1 shows the maximum reflection densities obtained with the developers stored at 40°C for 3 days, 7 days, and 14 days. It is understood that the maximum concentration changes over time due to poor charge stability, but the current 1W agent of the present invention shows almost no change in concentration over time and is extremely stable.

In addition, when printing was performed using the obtained offset master, the master with a maximum density of 1.7 or more received ink in the non-image area and caused background stains.0 Example 2 Comparison of Example 1 20% of lauryl methacrylate-methacrylic acid copolymer synthesized as shown in Example 1
Solution 15.9 and Exemplary Compound (1) 1,? A toner solution was prepared and tested in the same manner as Comparative Developer A, except that 30 g of a xylene solution prepared by heating and dissolving the developer was used in place of aluminum stearate. Like the developer-1 of the present invention, it was a liquid developer with extremely excellent charge stability.

Example 3 100 g of stearyl methacrylate and 1 OH of methoxypolyethylene glycol methacrylate were stirred twice. Then take 100 I of the product solution and add 50 g of methyl methacrylate, 10 I of styrene 3511 hydroxyethyl methacrylate and AIBN.
1 and 0 g were added, and the mixture was heated and stirred at 75° C. for 5 hours. The product was a stable emulsion with an average particle size of 0.15 microns.

Next, oil blank I-IB manufactured by Orient Chemical Co., Ltd.
B8! i was dissolved in 60 g of xylene, and this was added dropwise to the above-produced emulsion i. After stirring, exemplified compound (8) was added in place of exemplified compound (1) in Example 2. I I! A charge control agent prepared in the same manner as in Example 2 except for using the log of an ethanol:xylene (2:8) solution in which 100% It was used as a developer. The liquid developer had excellent charge stability almost the same as the developer of Example 2.

Example 4 Comparative example of Example 1 to provide an insoluble copolymer with 70
Polymerization was initiated by addition of ^IBNO,6/ on a water bath at °C.

The product was a white emulsion coating of a composite resin dispersion with extremely excellent dispersion stability. Then, a solution of 5g of oil black HBB dissolved in 20j of xylene was added dropwise to the emulsion solution while stirring.

Further, as a charge control agent, 15 g of a 20% bath fi of the lauryl methacrylate-methacrylic acid co-I composite synthesized as shown in Comparative Developer A of Example 1 and the exemplified compound (1
6) A toner solution was prepared in the same manner as the comparative developer^ except that 1 g of the developer was mixed with 30 g of a xylene solution in which 1 g was heated and dissolved, and aluminum stearate was used in place of the aluminum stearate.

Next, as a binder, 10II of the octylhavester derivative of styrene maleic anhydride (volume value 165) was dissolved in a mixed solvent of xylene 801, butanol 20I, and tetrahydrofuran 20.9, and an organic photoconductive compound of 2.5- Bis(4'-diethylaminophenyl'
)-1,3,4-oxadiazole (8 g) was dissolved in a 1% methanol bath solution of ethyl violet as a sensitizing dye.
A photosensitive solution prepared by adjusting the total amount to 15ON with xylene was applied onto an anodized aluminum plate to a film thickness of 4βm and dried to prepare a printing original plate.

When the above printing original plate was subjected to Fuden, exposure area, and the above-mentioned solid body development, the painter's area showed good resistivity, and a printing plate was obtained.

Like the developer of Example 1, the liquid developer of this example also had excellent NFC charge stability.

Claims (1)

[Claims] (1) A liquid developer for electrophotography, characterized in that a highly insulating carrier liquid contains a compound having an amino group in a nitrogen-containing heterocyclic nucleus.