DD218699B1 - ELECTRIC PHOTOGRAPHIC FLUID DEVELOPER - Google Patents

Description

Field of application of the invention

The invention relates to a liquid developer for visualizing electrostatic charge images in electrophotographic and electrographic materials and devices.

Characteristic of the known technical solutions

Electrophotographic or electrocogenic liquid developers generally consist of an electrically insulating carrier liquid with dispersed therein colored pigments, which are coated for setting certain properties with a polymeric auxiliary and control substance (eg DE-AS 1934613, DE-OS 1772439, DE-AS 2103045). ,

The polymeric control agents impart to the dispersed colored toner particles a positive or negative electrical charge to the carrier liquid. At the same time they ensure the dispersibility of the toner and the stability of the dispersion and the fixation of the deposited toner particles on the substrate. Polymeric control substances are known from copolymers prepared by complex polymer reaction from 2 to 4 individual components (DE-AS 1933362).

The copolymers also used with structural elements of 1,2-dicarboxylic acid derivatives, in addition to a relatively complicated manufacturing process lungs require complicated purification operations. Due to the hydrophobic character of these molecules, the fixing properties of the developers on hydrophilic surfaces, as well as on layer surfaces with basic character, such as

z. As organic photoconductors, not sufficient.

In addition, in developer systems in which metal strips are used as additional auxiliaries, a certain acidity behavior of the control polymer is required, which is not defined by the above substances adjustable. This leads to less than optimal results.

Object of the invention

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

Explanation of the essence of the invention

Since the known liquid developers often have insufficient fixing properties on hydrophilic surfaces and those with a basic character and have an undefined, adjustable acidity behavior, the object is to provide a liquid developer whose toner particles have the required hydrophilicity and a matched acidity behavior.

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, as auxiliaries and control one or more copolymers having structural elements the general formulas

-сн-сн-

O = C C = O

он Ar ¹

(1)

and or

-CH-CH-

I I O = C C = O

Il (2),

OH N ''

in which

R ¹ , R ^{2 are} identical or different, alkyl having 10 to 30 carbon atoms, -CH ₃ ,

-СЛ . --Γί

/ -Ch ^N

3

FT

ГГ

- / \ -NR ³ R ⁴ , - (CH J -OR ³ , \ / ^d *

- (CH ₂ J _x -KR ³ R ⁴ , - (CH ₂ J _x -COOH, - (CH ₂ J _x -COOMe,

, -CH-CH-CH ₂ -OH *

R ³ , R ^{4 are the} same or different, H, alkyl of 1 to 4 carbon atoms; Y is halogen, -NO ₂ , -C00R ³ , -C00Me, -CHO, -CN,

Me any metal atom

X 1 to 10

mean

and olefinic polymerizable compounds. Good results are obtained when R ¹ , R ^{2 are} from 10 to 100%, preferably from 60 to 100% long-chain alkyl groups. A liquid developer according to the invention which is prepared in a manner known per se by kneading or grinding a colored pigment with a control substance constructed in the manner mentioned and dispersing in an electrically insulating carrier liquid, optionally with the addition of monovalent or polyvalent metal soaps, exhibits good polarity. and development properties as well as a good fixability on the various, in particular hydrophilic underlays and organic photo semiconductors. Through variation and combination, the properties of the developer are changeable and can thus be adapted to the various circumstances of the practice. Depending on the substituents and optionally further auxiliaries and additives which can interact with the control substance, both positive and negative toner charges can be realized. As colored pigments carbon black, insoluble in the carrier liquid dyes such. As aniline black, Sudan black, Wonfanolechtschwarz or phthalocyanines, fast-red dye, benzene-insoluble yellow dyes, Wofanolechtgrün be used inter alia. Carrier ^liquids are aliphatic hydrocarbons, chlorine, fluorine or chlorofluorocarbons with a volume ^resistance > 10 ^l3 Ocm and a dielectric constant <3.

Suitable olefinic polymerizable compounds are those common in polymer chemistry, e.g. Ethylene, propylene, isobutylene, styrene, methyl styrene.

embodiments

example 1

0.065 base moles of an alternating isobutylene-maleic anhydride copolymer are reacted with 12.28 g of Stearyl alcohol and 1.74 g of N, N-dimethylaminoethanol. The reaction product is milled with 2 g of carbon black and 25 ml of a carrier liquid of a high-boiling aliphatic hydrocarbon with the addition of 0.03 g of cobalt stearate in a ball mill for 10 hours.

15 ml of this concentrate are mixed with 1000 ml of said carrier liquid to give a positive-working liquid developer for electrophotography with good adhesion of the toner coating on ZnO paper.

Example 2

0.065 base moles of a propylene-maleic anhydride copolymer are esterified with a mixture of 6.0125 g of lauryl alcohol and 7.8000 g of stearyl alcohol, and the reaction product is further processed analogously to Example 1. After diluting 10 ml of the obtained concentrate with 1 000 ml of carrier liquid, an electrophotographic liquid developer having a negative charge of the toner particles is obtained. The fixability on a hydrophilic surface is very good.

Example 3

10 g of alternating propylene-maleic anhydride copolymer are reacted in molar ratio 1: 1 with dilaurylamine in acetone at room temperature. The resulting polymer-analogous modified polymer is milled with 2 g of carbon black and 50 ml of an aliphatic carrier liquid for at least 20 hours in a ball mill. 20ml of this concentrate will be included.

1 000ml of said carrier liquid diluted. A liquid developer for electrophotography with negative charge of the toner particles is obtained. The adhesive strength of the deposited toner particles on surfaces having a hydrophilic, in particular basic character is good.

Example 4

10 g of an alternating isobutylene-maleic anhydride copolymer are reacted analogously to Example 3 to 65 mol% with distearylamine to the corresponding amic acid. The remaining anhydride groups are modified in the same way with morpholine. If the reaction product is processed to the finished developer as in Example 1 with the addition of 0.1 g of cobalt naphthenate, it receives positively charged toner particles. Shows very good wrapping and fixing properties.

Example 5

0,065Grundmol ethylene-maleic anhydride copolymer are to 45Mol-% with Distearyiamin to 20 mol% with piperidine and 35Mol-% with morpholinopropylamine first converted to the corresponding amide acid, and then subjected at 140 ⁰ C to condensation, the primary acid amide converted into the imide becomes.

With the addition of 0.05 g of nickel stearate, an electrophotographic liquid developer is prepared analogously to Example 3. Its toner particles are positively charged and are well fixable on ZnO support.

Claims (3)

An electrophotographic liquid developer consisting of a carrier liquid, a colored toner and one or more copolymers based on maleic anhydride and any olefinic polymerizable compounds as auxiliary and control agent, characterized in that the liquid developer as auxiliaries and control one or more copolymers having structural elements of general formulas -CH-CH-O = CC = O ₍₁₎ OH OR · ¹ " H OR · and or -CH-CH-I I о = 6 c = o LI OH ₇ N FT Irin the
R ¹ , R ^{2 are the} same or different, alkyl having 10 to 30 carbon atoms, -sn ₃ , - / ^ - (и ct -NR ³ R ⁴ , - (CH ₂ ) _X -OR ³ , - - (CH ₂ ) _x -C00H, - (CH ₂ J _x -CH ₂ (-O-CH ₂ -CH ₂ J _x -OR ³ , -CH-CH-CH ₀ -Or !, -CH ₀ -CH-CH ₀ 0 R ³ , R ^{4 are} identical or different, H, alkyl having 1 to 4 carbon atoms; Y is halogen, -NO ₂ , -COOR ³ , -COOMe, -CHO, -CN; Me any metal atom X 1 to 10 mean and contains olefinic polymerizable compounds. 2. Electrophotographic liquid developer according to claim!, Characterized in that R ¹ , R ² is up to 100% long-chain alkyl. 3. Electrophotographic liquid developer according to claim 2, characterized in that R ¹ , R ² is up to 100% long-chain alkyl.