DD218697A1 - ELECTRIC PHOTOGRAPHIC FLUID DEVELOPER - Google Patents

Abstract

The invention relates to a liquid developer for visualizing electrostatic charge images in electrophotographic or electrographic materials or arrangements. The object and object of providing a liquid developer having improved charge and disperse properties through improved homogeneity and disperse phase interaction and improved charge retention and stability is achieved by adding one or more polymeric materials to the liquid developer with structural units of the general formulas 1 to 4 where R1, R2, R3, R4 R5, R6 -H, alkyl; Y halo, - NO2, -COOR5, COOMe, -CHO, -CN; may be any metal atom; X1 to 10; and olefinic polymerizable compounds. Formulas 1 to 4 and R1 to R4

Description

Electrophotographic liquid developer

Field of application of the invention

The invention relates to a liquid developer for the visualization of electrostatic charge images in electrophotographic or electrographic materials or arrangements,

Characteristic of the known technical solutions .

Electrophotographic or electrographic liquid developers generally consist of an electrically insulating carrier liquid with colored pigments dispersed therein, which are lined with a polymeric auxiliary and control substance to set certain properties (eg DE-AS 1934 613, DS-OS 1772 439, US Pat. DE-AS 2,103,045, DE-AS 1933 362). Often, this control agent is formed from suitably modified maleic anhydride copolymers.

The polymeric control agents impart to the dispersed colored toner particles a positive or negative electrical charge to the carrier liquid, thereby facilitating the proper functioning of the developer. At the same time they ensure the easy dispersibility and high dispersion stability of the developer and ensure the fixation of the developed image.

Thus, a whole range of different functions and properties must be met by a polymer.

12APR 1932 * 002243

DIGS ilJt Z'Jr: -O: -: 5, GCU G13 - ГЭ1ІІЗІ 13 g Г2 C α ogl СгГ іЮСІП-cation are strong dislocates eingesch eggs properties of INTV <icklers and its darait. Adaptation to various applications, also warden The control substance envelops only ice pigments and thus only stabilizes their electrical charge. The associated counter charge is normally distributed diffusely in the carrier liquid and thus not specifically stabilized. This leads to difficulties in forming and maintaining the polarity and dispersity properties of the developer and has a negative influence on its developing ability and long-term stability.

Object of the invention

The aim of the invention is to improve the development properties and the stability of electrophotographic liquid developers.

Presentation of the, Vesens of the invention

Since unsatisfactory development and stability properties are often present in the known liquid developers due to insufficient / interaction between the toner particles and the carrier liquid, the object is to provide a liquid developer which is more favorable due to an improved interaction between the homogeneous and the disperse phase. and having qispersity properties, as well as improved charge retention properties and increased stability. According to the invention the object is achieved by the electrophotographic liquid developer consisting of a carrier liquid, a colored pigment and one or more copolymers based on maleic anhydride and any olefinic polymerizable compounds as auxiliaries and control additionally είη or more polymeric substances structural units of the general formulas

-CH-CH-Mi

Il * - '

C = C C = O *

I ·! I 2 OFTOR

(2)

: ι зѴ, -CH- I O = C

and / or -CH-CH- (3)

and / or -CH-CH- (4)

О = С C = O

where D ei

3 4 R, R, R, R are the same or different, alkyl of 10 to

30 carbon atoms, optionally substituted -H, -CH ₃ , -f \ _c , - / H

-NR ⁵ R ⁶ , -

- (CH ₂ ) _x -OR ⁵ , -

- (ch ₂ ) _x -cooh, - (сн ₂ ) _х -сооме,

-CH ₂ - (O-CH ₂ -CH ₂ J _x -OR ⁵ , -CH-CH-CH ₂ -OH, -CH ₂ -CH-CH ₂ ;

R, R are the same or different, -H alkyl with

1 to 4 carbon atoms;

Any metalato.n;

Л j. ij Z S J. U

mean, and olefinic polymerizable «compounds contains.

The additional polymeric material is able to absorb and stabilize the negative counter-charge that corresponds to the positively charged toner particles and thus prevents or impedes the recombination of the charges. A liquid developer according to the invention which is prepared in a known manner by grinding a colored pigment optionally with the aid of carrier and control substances insoluble in carrier liquid, and dispersing in an electrically insulating carrier liquid which contains one or more of the polymeric substances according to the invention Over a long period of time constant and reproducible dispersion and Entvvicklungseigenschaften, Oa the solute in the present medium has a surface-active © effect shows stabilization of the dispersion at the same time even at relatively low particle charges, whereby the degrees of freedom in the adaptation of the developer to different applications trap quite crucial be enlarged. By stabilizing the counter charge associated with the toner particles, the specific charge and the dispersion stability increase.

Depending on the building blocks used, both negative and positive particle charges can be realized

 As colored pigments can be used

- different soot types,

- in the carrier liquid insoluble dyes such. Aniline-black, Sudan-vvarz, .Vof anolechtschvvarz, or ... phthalocyanines, fast-red dyes, petrol-insoluble yellow dyes, Jofanoichtgrün u.a. Auxiliary and tax materials

are Роіупогэ, Соэоіумзrs, Polynercishus Нэ rze,. \ '2ΐ υ rna rze, .axis, metal salt лсгізі и.о.

Carrier liquids are aliphatic hydrocarbons, chlorine, fluorine or fluorochlorohydrochloride with a volume resistance of> 10 "Jl .cm and a dielectric constant of ^ ^ 3 suitable.

Suitable olefinic polymerizable compounds are z.S. Ethylene, propylene, isobutylene, styrene, methylstyrene "Polymeric substances according to the invention are polymers having a main chain consisting essentially of carbon atoms and a proportion of corresponding side groups ensuring the solubility in the carrier liquid used, functional groups also having to be present for stabilizing the corresponding charge.

For exemplary embodiments 8eispiel 1

A copolymer of 50% oil, ethylene and 50% maleic acid phenylimide units is coated in a manner known per se by kneading or grinding in a ball mill or by other suitable manipulations around soot particles. 6 g of this polymer-coated pigment are dispersed in a solution containing 6.5 g of a copolymer of 50 MoI ^ propylene and 50 mol% maleic acid stearyl imide units in 100 ml of a paraffinic carrier liquid. After dilution of 10 g of this concentrate with 1 liter of carrier liquid, a liquid developer for electrophotographic purposes is obtained, which gives images of high density. The dispersion is stable over several months. The particle charge is positive,

Example 2

g of a polyamide-6-coated carbon black pigment, which accounts for 3.2 g of polyamide per 2 g of carbon black, is dissolved in a solution of 100 ml of aliphatic carrier fluid and a copolymer

dispersed to 50 Μο1-χ> from propylene units, to 30 mole-> i of maleic acid stearylimide units, to 10 mole percent of maleic acid laurylimide units and to 10 mole percent of maleic acid p-methoxyphenylimide units. The concentrate is diluted 1: 100 with carrier liquid to give a ready liquid developer for electrophotography with negatively charged toner particles. It shows good and reproducible development varia-

Example 3

An alternating copolymer of isobutylene and hexanoic anhydride which was completely decomposed is coated, as in Example 1, with carbon black particles and aivar in the proportion of 1 part of carbon black: 1.5 parts of copolymer, 5 g of this pigment in 100 ml of a solution of a copolymer of 50 ethylene-ethylene units, 40 equivalents of carboxylic acid coco- enes, and 10 moles of maleic acid p-pyridyl- ₁ : ₁ -diol aliphatic high-boiling carrier liquid by grinding in a ball mill for 5 hours.

Dilute 15 ml of this solution with 1 l of the said carrier liquid, then seal an electrophotographic liquid-solvent with charged particles. It works on several i-ionote bases reproducible,

Example 4

an alternating copolymer of od-methylstyrene and maleic anhydride, which has been converted completely into the corresponding 2-pyridylimide, is processed into the toner analogously to Example 1,

5 g of this toner are dissolved in 100 ml of a high-boiling aliphatic carrier liquid in which 7.2 g of a copolymer of 50 MoI-V, ethylene units, 35 moles of maleic acid cetylimide units and 15 moles of maleic acid distearylamic acid units dissolved or dispersed, to give a developer concentrate, yield 12 ml of this concentrate, when

diluted with 1000 ml of carrier liquid, a ready-to-use electrophotographic liquid developer with positive particle ligation. It is dispersion stable over a long time and shows reproducible development capacity,

Example 5

The same toner is prepared as in Example 3. 6 g of this toner are dissolved in a copolyester solution of 50 mol% propylene units, 40 MoI-Jo maleic acid stearyl imide units and 10 mol% monoimide phenylimide units in a high boiling point dispersed aliphatic carbonic acid. The resulting liquid developer concentrate shows after dilution with carrier liquid in the ratio 1: 100 very good development properties for positive charge images and high dispersion stability over a long time.

Claims (1)

- о - ^ rfindungsansprucn Electrophotographic liquid developer, consisting of a carrier liquid, a colored pigment and one or more Copoylneren based on maleic anhydride and any olefinic polymerizable compounds auxiliary and control agent, characterized in that the liquid developer additionally one or more polymeric substances having structural units of the general formulas r-r- O = C G = O (1) ! 1 1 2 OR-OR and or - (JH- (JH- (2) O = C C = O Ji I ₂ / \ з R R and or -CH-CjH- (5) O = CC = O Ji N ₄ \ ^/ Ь Ifs * R- RR and / or г -CH-CH- O = C C = O ¹ 1 FT as or different; .-'-. IG up to 30 carbon atoms, SUuS Li uu н, - (CH ₉ ) -OR ⁵ , - (CH ₀ ) ^ - NR ³ R ⁶ , - (CH ₀ ) ^ - COOH, - (CH ₀ ) -COOMe, - CH ₂ (-O-CH ₂ -CH _{2 x} -0R ³ , -CH-CK-CH ^ tCH, -CH ₂ -CH-CH ₂ ; O O R ", R are the same or different, -H, alkyl ait 1 to 4 carbon atoms; Y is halogen, -NO ₂ , -COOR ³ , -COOH, COOMe, -CHO ₁ -CN; Me any metal atom X 1 to 10 mean and olefinic polymerizable compounds.