JPS59157658A - Charge controlling agent for liquid electrography developer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to electrography. More specifically, the present invention relates to charge control agents for liquid electrographic developers.Technical Background In the field of electrography, a charged image is formed on a substrate and then the charged image is electrographically developed. It is visualized by contacting with the agent composition. These compositions are available in two forms, dry and wet, each with its own unique requirements and advantages.

Liquid electrographic developers are conventional dispersions of toner particles, usually pigments and binder resins, dispersed in an electrically insulating carrier liquid, such as a volatile hydrocarbon fraction. The binder resin has the function of binding the pigment to the copy paper on which the dark latent image is developed. The developer may also contain additives such as stabilizers to maintain a stable dispersion of toner particles. Liquid developers also often contain stock control agents to maintain a constant charge level.

A particularly useful liquid developer is U.S. Pat.
Disclosed in the issue. This developer is a combination of an electrically insulating carrier liquid, toner particles (1) stably dispersed therein, and a quaternary ammonium salt monomer and a solubilizing monomer dissolved therein. It has a polymer (2) and a copolymer (3) of additional polar monomers and solubilizing monomers also dissolved therein. The amount of solubilizing monomer contained in each of the above copolymers is
The amount is sufficient to solubilize the copolymer in the carrier liquid alone.

The liquid developers described in said US Pat. No. 4,273,849, however, have certain drawbacks regarding their charge stability when they are used over time in multiple copying steps. In particular, as a result of the increased developer charge per unit amount of dispersed toner, the quaternary ammonium charge control copolymer is deposited onto the electrostatic image at a slower rate than the toner. This uneven rate of consumption and the resulting increase in charge per unit amount in the developer makes it difficult to replenish the developer and causes uneven image density from copy to copy.

OBJECTS OF THE INVENTION It is an object of the present invention to stabilize the charge of a liquid electrographic developer per unit amount of toner in order to reduce the rate at which unit ambiguous charge increases during use.

Structure of the Invention According to the present invention, the above-mentioned object is to provide a quaternary ammonium salt single liquid, a solubilizing monomer, and -〇〇OH.

An acidic functional group selected from the group consisting of -8o3H and -PO3HR (wherein R is hydrogen or an alkyl group)
This can be achieved by a charge control agent containing an addition copolymer of an insolubilizing monomer having a function (function). Base:
-PO3I (When R in R is an alkyl group, the alkyl group is preferably a C4-5° alkyl group, such as a methyl group, a globyl group, an amyl group or a hexyl group. Most preferably, said alkyl group is It is a C4-4 alkyl group.

The charge control agent of the present invention comprises an electrically insulating carrier liquid;
and (1) the toner particles dispersed therein.
and (2) a charging component which is also soluble in the carrier and is an addition copolymer consisting of a polar monomer and a solubilizing monomer. It is particularly useful in electrographic liquid developer compositions.

In a preferred embodiment of the invention, the charge of the developer per unit amount is further stabilized against changes when the toner contains neutral or basic pigments.

The liquid carrier used in the developer of the present invention is:
It has a low dielectric constant and electrical resistance so that there are no multiple fractures that interfere with the electrostatic charge pattern to be developed. The carrier liquid has a dielectric constant of less than about 3 and a volume resistivity of more than 10 ToΩ,
and should be chemically stable. Suitable carrier liquids include halogenated hydrocarbon solvents such as trichlorotrifluoroethane. Hydrocarbon solvents such as isoparaffinic hydrocarbons and cyclohydrocarbons such as cyclohexane are useful as such carrier liquids. The carrier dispersion preferably contains 2
The toner, which is a mixture of different electrically insulating liquids, is dispersed in the liquid carrier and acts as the imaging (ie, marking) particle component. That is, this marking particle component is attracted to the electrostatic charge image on the element to be developed. The toner is
It has a colorant and, optionally, a binder polymer that attaches the colorant to the image-bearing element. Colorants can be selected from one or more of a variety of dyes and pigments. One preferred colorant is carbon black. However, in practice, as a general rule, one color index (Co1our In
d@x)”, 5econd EditIon
.

Any compound described in 1956*Volurne I and ■ can be used.

Preferred toners include neutral or basic pigments,
For example, it has a neutral or basic carbon black pigment. The neutrality or basicity of a pigment is determined, for example, by ASTM D 1512 as - for that pigment.
-60(76). For details of this ASTM method, see B.5ehu
Bert et al.'s report Analysis II is of
Carbon Black".

Encyclopedia of Industry
real chemical analysis,
Volume B (Reprint page 51-52゜pH)
, John Wllley and 5ons, I
It is reported in nc. Neutral or basic pigments obtained by this method exhibit a value of 7 or higher.

As mentioned above, a binder polymer can be used with the toner particles if desired. Such binder polymers include a variety of materials, such as halodanated preolefins, addition polymers such as acrylic polymers, and condensation polymers. Such polymers are preferably I-lyester ionomers, such as those disclosed in US Pat. No. 4,252,921.

The charge control agent of the present invention is preferably soluble in the carrier. 1 carrier soluble" means that the charge control agent is soluble in the electrically insulating carrier in the absence of toner components at the concentration level of the charge control agent at which the charge control agent is used in the developer. It means that.

The monomer components of the charge control agent include at least the following components: a quaternary ammonium salt monomer, a solubilizing monomer, and -〇〇〇H, -8o, H, and - PO,H
A monomer having an acidic functional group selected from the group consisting of R.

Examples of suitable quaternary ammonium salts include: methacryloyloxyethyltrimethylammonium p-toluenesulfonate dimethyloctadecylvinylbenzylammonium chloride 2-vinyl-N-methylpyridinium methylsulfate N -Methyl-N-methacryloyloxyethelpiperidinium bromide N-methacryloyloxyethelpyridinium nitrate Alternative solubilizing monomers include: 3 to 10 carbons in the alkyl group. Alkylstyrene and alkoxystyrene having atoms 8 to 22 in the alkyl group
alkyl acrylates and methacrylates with 8 to 22 carbon atoms in the alkyl group, vinyl alkyl ethers with 8 to 22 carbon atoms in the alkyl group, and vinyl alkyl ethers with 6 to 22 carbon atoms in the alkyl group.
Vinyl ester of alkanoic acid having 22 carbon atoms.

Specific solubilizing monomers that can be used include: t-butylstyrene, 4-entylstyrene, 4-hexylstyrene, 4-octylstyrene,
p-Amyloxystyrene.

lauryl acrylate, lauryl methacrylate hexadecyl methacrylate, octadecyl methacrylate,
Eicosyl acrylate, tocosyl methacrylate, vinyl caprate, vinyl laurate, vinyl stearate
vinyl stearate, vinyl caprate, and vinyl tocosade.

Suitable insolubilizing monomers with acidic functionality include addition polymerizable monomers, such as olefinic and acrylic monomers with essential acidic functionality. Typical acidic monomers include: Coon-containing monomers Niacrylic acid Methacrylic acid Vinyl Benzoic acid Methyl acetate 18O3H-containing monomers: Sulfoethyl methacrylamide Sulfonithyl methacrylate Styrene sulfonic acid PO,HR-containing monomers: vinylbenzyl ethyl phosphate vinylbenzyl phosphonic acid vinyl phosphonic acid vinyl ethyl phosphate In addition to the quaternary ammonium, solubilizing, and acidic monomers described above, the above charge control agents include, for example, Additional other monomers can be included to adjust the solubility of the polymer in the carrier and provide other desired properties.

The quaternary ammonium salt electropolymer useful in the present Kanmei number-body developer typically has an intrinsic viscosity within the range of 0.1 to 0.8. This viscosity determination was carried out at 25 °C at a concentration of 0.25 g of polymer in 100 rnl of chloroform.
It can be carried out at a temperature of

The resulting polymer may be derived from one or more solubilizing monomers, one or more quaternary ammonium salt monomers, and one or more insolubilizing monomers. Contains repeating units. The typical quaternary ammonium salt coelectrolyte used in the liquid developer of the present invention includes 85 to 96 moles of solubilized monomer units and 10 to 2 moles of acidic insolubilized monomer units. unit.

It contains 5 to 1 mole weight of quaternary ammonium salt monomer units.

The solubility of the quaternary ammonium salt copolymer in the carrier liquid can be controlled, for example, by adjusting the amounts of the solubilizing monomer and the insolubilizing monomer. If the solubilizing monomer has very long alkyl groups, it is possible to make the polymer containing that monomer very well soluble in a hydrocarbon bulk carrier liquid, and in doing so, the insolubilization The monomers may have relatively short alkyl groups. On the other hand, if the alkyl group on the solubilizing monomer is relatively short, it may be necessary to make the alkyl group on that monomer somewhat longer if an insolubilizing monomer is used.

The relative abundance of quaternary ammonium salt monomers can be varied to provide polymers that exhibit different V7 electrical properties when incorporated into liquid developers.

The developer of the present invention may further be used, for example, in U.S. Pat.
3,849 and 3,849,165, which are soluble in carriers, as a charging agent component. "Soluble in one carrier" means that the charging agent has the ability to dissolve in the liquid carrier in the absence of the above-mentioned toner components and at the concentration level used in the developer. means.

The soluble polar copolymers described above are addition copolymers of a polar monomer and at least one solubilizing monomer. The amount of polar monomers is at least 1.5X10 moles per copolymer I11.

As monomers for addition copolymerization with polar monomers to obtain soluble polar copolymers, solubilizing monomers as mentioned above and, if desired, insolubilizing monomers, e.g. Styrene, as described in U.S. No. 23,849,165 by Tably et al.

Vinyl toluene, ethyl acrylate, ethyl acrylate, butyl acrylate, ether methacrylate, 7
These include oral pill methacrylate, butyl methacrylate, vinyl acetate, vinyl propionate, and vinyl butyrate. The relative layers of these nocomomers are
As discussed above with respect to the quaternary ammonium salt copolymers, selections are made to produce polar addition copolymers with the desired solubility.

Suitable polar monomers include sulfoalkyl acrylates and methacrylates, metal salts of sulfoalkyl acrylates and methacrylates, and amine salts of sulfoalkyl acrylates and methacrylates. Preferably, the sulfoalkyl groups described above contain 1 to about 4 carbon atoms.

Additionally, metal and amine salts of acrylic and methacrylic acids, and the aforementioned salts of vinylbenzoic acid, vinylphenylacetic acid, 9α-aryacrylamide stearic acid, monoalkylphthalic acid and styrene sulfonic acid, and mixtures thereof are also suitable. It is. The metals of the salts mentioned above are metals of Group 1, Group 1a, Group 11b, and Group 1 of the periodic table.

Preferred polar monomers are acrylic monomers.

Note that the term "acrylic acid" as used herein broadly includes methacrylic acids, and salts and esters of such acrylic acids.

Specific examples of such acrylic polar single needles include: sulfoethyl methacrylate; sulfoethyl acrylate; sulfoglobyl methacrylate; sulfobutyl methacrylate; sulfoether methacrylate, sodium salt: sulfoether. methacrylate 2
Partial sodium salt; Sulfopropyl methacrylate, sodium salt; Sulfobutyl methacrylate, potassium salt; Sulfoether methacrylate, lithium salt; Sulfoether methacrylate, copper salt; Sulfopropyl methacrylate, dimethyl ammonium salt; Sulfoether methacrylate, diethylammonium salt; Sulfomethyl acrylate, dimethyl ammonium salt; sodium methacrylate; sodium acrylate; lithium methacrylate; potassium acrylate; barium methacrylate; zinc methacrylate; cobalt methacrylate; ferrous acrylate; magnesium methacrylate; zinc acrylate; and mixtures thereof.

The liquid electrographic developer of the present invention has a liquid electrographic developer of about 0.05%.
0.01 to 5% by weight soluble polar copolymer, o, oi to 5 mil 5 violet grade ammonium salt copolymer, and 0.01
Contains ~5% by weight of toner. A preferred developer is 0
02 to 0.5 weight soluble acrylic inert copolymer,
It contains a quaternary ammonium salt copolymer with a needle size of 0:02 to 0.5, and a toner with a needle size of 0.02 to 0.5.

In the examples described below, the developers of the invention are evaluated with respect to replenishability R1, or charge distribution. For purposes of the present invention, the replenishment potential R is defined as the ratio of the initial charge/volume to the final charge/volume after forming an electrographic image using Ll of the developer and performing replenishment. It can be defined as The extent of imaging and replenishment was predetermined to use and replenish three times the number of marking particles in the initial developer (e.g., if the developer contains 0.2F toner, Develop and replenish 0.6 g of 3 medium). The replenisher used was a five times (5x) concentrate of the original developer. Gusitance grip that carries charges (coulombs) before and after:
Kelthly InstrumentsCapaci
tance Bridge (Tettex Inst
rumments.

I n c -p USA Penn 5ylvar + Im,
(available from ). Divide this charge measurement by the toner mold movement (kg) to calculate the charge per kg of toner/
Everyone (coulombs/kg) was calculated.

Embodiment of the Invention Example 1: The following chemical agent ingredients were applied in a l5opar G (registered trademark) -5olvasso 100 liquid carrier system. In addition, So'1vasso 10
0■ is the open collar of alkylated aromatic liquid, and l5opa
r G■ is a trademark for Iso7 and rough-in hydrocarbon liquids.

The pigment density of developer 1/this was 0.7 g.

The density of 5olvesso 100 for developer 11 was about 21.9.

A (1) Toner.

Pigment Ac1djc Raven 1255■
1 carton black binder [neopentyl-4-1,2methylcyclohexene-1,2-dical xylate-coterephthalate-5-(N-botadione p-toluenesulfonamidosulfonyl) incalate] Kishij acrylate) 97/3(3
) Quaternary Ampoly(1-Bunalstere 0.2 Oxyethyltrimethylammonium-p-toluenesulfonate) B(11) Nurpigment Ac1dlc Raven 1255■
1 Carbon black binder Poly[neopentyl-4-1,2methylcyclohexylate-1,2-dicargexylate-co-terephthalate-5-(N-botadiop-)luenesulfonamidosulfonyl)inphthalate] Component acrylate-colithium 60/36/3.610.4 (3) IS 4 M an poly(1-buterstere)
0.3 monium methacrylic acid
and control agent - comethacryloyl 0.
2-oxyethyltrimethylammonium-p-toluenesulfonate) C(1) Toner pigment Regal 300 ■ 1 Kagen black binder Poly[neopentyl-41,2-methylcyclohexenol 1,2-dicarboxylate-co-terephthalate-5- (N-Botadio-p-toluenesulfonamidosulfonyl) inctalate] (2) Addition polarity Poly(1-butelstele) 1.
5 Copolymer N-Cola Uril Methacrylic Acrylate-Colithium Methacrylate-Co-Methacrylic Acid) 60/36/3.610.4 (3) M4M Poly(1-Buterstere 0.
These developers each contained 0.5 parts of plasticizer.

It contained 0.25 parts of wax and 0.125 parts of dispersant for the wax.

In this example, Merrill U.S. Pat.
No. 849, column 5, the replenishability R of a control liquid developer containing a quaternary ammonium charge control polymer as described in Co. compared.

The developer of the present invention was the same as developer A above.

The charge control polymer used in the control developer was (,)
A solubilizing monomer, an insolubilizing monomer having no acidic group, and a fourth
Is it an addition ternary copolymer of grade ammonium monomers,
Or (b) was an addition coelectrolyte of a monomer and a quaternary ammonium polymer. All other aspects were common to the control developer and the developer of the invention.

The results for R values are reported in Table 1 below.

Margin below From these results, it can be seen that when the insolubilizing monomer is acidic, the developer replenishment possibility R is greater than the charge control polymer containing a non-acidic insolubilizing monomer or not containing an insolubilizing monomer. It can be seen that it is improved compared to

Examples 6-8: These examples illustrate that the replenishability R is further increased by the use of non-acidic colorants.

The methods described in Comparative Examples 2 to 5 were repeated using developer A. Rave neutralized by washing as a layer colorant.
n 1255■Car? Black or Regal
300 ■ Kadenblack was used for one history. The addition polar copolymer and quaternary ammonium charge control polymer formulations were also varied as described.

The +aR of replenishment potential is reported in Table 2 below.

In the following margin, compare the R values of Examples 6 to 8 with the R value of the developer of Comparative Example 3 (same developer except for the percentages indicated). The results of the comparison show that basic or neutral pigments significantly improve the replenishability of the developer of the present invention compared to acidic pigments.

“Electrography” and “electrography” as they are used herein.

It has a broad meaning. i.e. in these words.

Also included is an imaging process that involves creating an electrostatic charge formed on a surface with or without blinding light. The words "electrograph 2 fee" and 6 electrograph fee are.

Therefore, electrophotography
and the process of the song.

Effects of the Invention According to the present invention, the replenishability of a liquid electrographic developer can be improved by incorporating certain charge control agents into the composition of the developer.

Claims (1)

[Claims] 1. (a) Quaternary ammonium salt monomer, (b)
Addition of a solubilizing monomer and (c) an acidic insolubilizing monomer having an acidic functional group selected from the group consisting of -COOH--8o sH and -PO3HR (wherein R is hydrogen or an alkyl group) A charge control agent for liquid electrographic developers containing a copolymer.