JPS6034106B2 - Manufacturing method of electrophotographic liquid developer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic liquid developer comprising particles of a colored polymer dispersed in an electrically insulating organic carrier liquid and containing a protective colloid, a modifier and optionally a dispersing aid. Relating to a method for manufacturing.

Electrophotographic reproduction is based on the creation of a cause-specific electrostatic latent image on the photoconductive layer.

This charged image is made visible when the colored toner particles of the developer, which have been brought into contact with the developer and have been abrasively charged, are deposited on locations that are charged to the opposite polarity, depending on their polarity. Several methods have already been described by which the objective of visualizing electrostatically charged images can be realized.

In one method, the photoconductor consists of zinc oxide layered with a binder on a flat base, such as paper and sheet. In this case, the electrostatically charged image produced is processed with a liquid developer. This type of liquid developer consists of one or several finely divided pigments dispersed in a liquid with high electrical resistance.
Resin-like substances are further dissolved in the liquid as a binder, and these substances fix the pigment particles attached to the electrostatically charged image to the copy during drying, that is, they improve the bran resistance. Its role is to attach the photoconductive layer to the copy in order to obtain the copy. In another method, the so-called transfer method, the photoconductor consists of an inorganic or organic material which may likewise be applied to a fan base.

In the known method, by charging the photoconductor and exposing the source to light, an electrostatically charged image corresponding to this source is created, and this charged image is
For example, visualization can be achieved by applying a powdered developer consisting of toner and carrier. The toner image can be transferred to smooth white paper in a variety of ways and fixed by heat, pressure, and solvent vapor. If the photoconductor is not on a flat base, but on a curved surface, e.g. a drum, the following steps: charging of the photoconductor, image exposure,
Development and transfer of the toner image to the paper surface may be repeated as many times as desired, with care being taken that any residual image remaining on the photoconductor after transfer is removed before the copying cycle begins again. .

Powdered toners of this type consist largely of pigmented polymers fused to resins and plasticizers. However, powder toners have the disadvantage of scattering and forming interfering deposits within the reproduction device, as opposed to liquid toners. Additionally, powder toners generally must be used with a pretreated carrier material in order to obtain the triboelectrification required for image formation (which may be the same or opposite to the polarity of the charged image). . Additionally, the powder toner must be fused to the paper to obtain a pseudo-fast copy, and this is generally accomplished by fusing. For machines with high copying capabilities, this requires considerable power consumption. Therefore, after developing the electrostatically charged image present on the light guide surface of the drum with a liquid toner as is known for zinc oxide paper and removing the excess liquid developer, the developed image is transferred to standard paper. Transcription was studied. However, it has been found that this image developed with a pigment dispersion can be transferred very poorly to paper. Various proposals have been made in German Patent Applications No. 2110409, No. 2144066 and No. 2147646 in order to improve the transfer of images of photoconductive drums developed with liquids to paper surfaces.
In this case, a completely special paper containing polymers and having a low oil absorption capacity must be used.

Other proposals (Federal Republic of Germany Patent Publication No. 21278
According to No. 38), the toner image present on the photoconductor, but not yet freed of excess developer, is transferred to a paper surface pre-wetted with a low-boiling solvent, thereby reducing the absorption of liquid developer. or be prevented. From DE 22 29 044 A1, a method has also become known which operates with a modified liquid developer consisting of colored polymer particles dispersed in a carrier liquid of high electrical resistance.
In this case, the polymer particles contain a solvent with high dissolving power.

Due to this and due to the selection of special polymers, the dispersed organosol particles have a certain adhesive force, which allows the adhesion of the separated particles under the influence of the electric force of the image to the photoconductor surface. Although extremely small, it is extremely large for a smooth standard paper that is brought into close contact with the toner image, thus resulting in the transfer of the photoconductor toner image to the paper surface being possible only by adhesive force without the use of an electric field. brought about. After the solvent portion of the expanded organosol particles penetrates into the paper intended for recording the image, the copy is fixed and is no longer sticky. However, the known methods of transferring a liquid-developed toner image from a photoconductive layer to a paper surface exhibit the following drawbacks: The use of specially pretreated paper is difficult due to the cost involved in producing the paper. It is uneconomical and makes the application of the process unfavorable: prewetting the copy paper with readily volatile solvents reduces the copying speed and increases the release of harmful solvent vapors into the surrounding environment.

When using the dispersed organosol as a developer,
Transfer from the photoconductor to the paper surface is not completely satisfactory, especially at high copying speeds, since the short contact time provided causes the toner to lose its adhesion to the photoconductor. This is because the toner cannot be completely overcome and therefore the toner is not completely separated from the photoconductor. Cleaning the photoconductive drum therefore becomes difficult before the next copying cycle. Furthermore, the organosols used do not necessarily have satisfactory stability due to the high solubility of the solvents used, since due to the high solubility of the solvent certain surface adhesives are already dispersed, leading to particle coarsening due to coalescence. This is because it is given to the polymer particles in the liquid. but,
It has been found that in order to obtain a good scale image of the characters with good stability, a toner as fine as possible is necessary. According to the proposal of German Patent Application No. P 2 2 6 2 6 0 35, an improved variant of organosol toners is now obtained by the addition of small amounts of water, thereby making it easier to transfer the toner image onto the paper surface rather than the photoconductor surface. However, toners of this type are limited in their manufacture by the use of aromatic and other solvents with a high solubility (ASTM carlyptanol number of 50 or higher) in a total solids content. Relatively high content for the amount of about 10
Contains at least % by weight of

Moreover, in case of continuous use, the solvent, due to its high melting power, can disintegrate the rubber rolls, guide devices, etc. present in the reproduction machine.
Damage the packing. According to the invention, it is as simple as possible to produce, has sufficient tack even with small amounts or no solvent, and is practical even when the applied toner image is subjected to high copying speeds. An electrophotographic liquid developer for use in transfer processes is obtained which allows it to be transferred completely from the photoconductor surface onto standard paper and which has improved stability even when the particle size is as small as possible.

The particles of the liquid developer according to the present invention consist of pigment particles covered by a polymer layer and are about 0.1 to about 12 French m.
It has a particle size of

In a preferred embodiment, the particles have a particle size of about 1 French meter to about 5 French meters. By particle size is meant the average particle diameter and a particle counting device, for example the Mico-Videoma, manufactured by Karls GmbH, Oberkotschen, is used.
n). According to the invention, contrary to the state of the art, a dispersed organosol is not produced which has the disadvantages of coarsening of the particles due to coalescence in the case of relatively low stability. The liquid developer according to the invention contains rather very fine stable particles, which enable good character resolution and, because of their small particle size, have good stability against sedimentation.

Furthermore, the absence of a solvent with a high solubility has the effect that the pigment particles coated with a polymer layer do not have mutual adhesion in the dispersion.

The polymers used are at least partially soluble when heated in the electrically insulating organic carrier liquid. However, at room temperature, the polymer has the lowest possible solubility in liquid.
In particular, polymers or copolymers are used which are subject to an integral swelling effect by the liquid at room temperature (this is the basis of the tackiness of the polymer to the recording material). For example, copolymers of vinyltols or styrene and acrylic esters have proven suitable. In particular, for example, Goodya Tire and Rubber Co.
re and Rjikir Co. ) made by Priorite (P
A vinyl toluene-acrylic resin known under the trade name 1iolite (2) is suitable. Finely divided carbon black is generally used as pigment, but all other known pigments or pigment mixtures can be used. In addition to pigments, dyes can also be used to sharpen the color tone and to influence the triboelectric properties. At this time, Flexprue B (Refle lau B) Isshiki index (C・
1) 42761 Alcohol-soluble Nigrosin (Nigroslnspritlaeslich)
- CI 50420 or Fetts
ch column rZ) HB or HBN-C. 1126150
Power; found to be particularly suitable.

Protective colloids that prevent agglomeration of colored polymers in insulating liquids include, for example, Phillips Petr.
oleumCo. ) manufactured by S-olprene
(2) A copolymer of butadiene and styrene known under the trade name is suitable.

In particular, copolymers such as those consisting of 75% by weight of butadiene and 25% by weight of styrene, such as Solprene (Solp
rene) 1205 proved to be advantageous.

Other substances which act as protective colloids are esters of polypinyl alcohol, such as polyvinyl stearate, esters of colophonium, esters of colophonium, esters of colophonium, eg Hercules Powder Co., Ltd.
Co. ) made by Pentaline.
(2) Aliphatic hydrocarbon resins such as those commercially available under the trade name Ejcor-eze (Esso Chemie GmbH) and the 110$ type or 5000 type known under the trade name Ejcor-eze■ manufactured by Esso Chemie GmbH. .

The added protective colloids can additionally be used as dispersion aids. As dispersion aids, other known compounds may be used, such as fatty alcohol polyglycol ethers such as those under the trade name Genapole S-020, Emulso M, or fatty acid polyglycol esters. For example, emulzogen (
Emulso Hoko n) SG (all of the above products are manufactured by Farbwerke Hoechst)
company's) are applicable.

As a regulating agent to influence triboelectrification,
, Reflex Blue AM ``(Ref
auAMF)-C. 1.427701- or Reflexful-A Kenichi G and salts prepared by reaction of fatty acids having 16 to 18 carbon atoms with the dye bases described below and subsequent milling in a roller mill. Can be used: Insulin base
N (0.1.Solvent blue-
7(S 1vent(lndulinbaseN)
blue7)), 50400B methyl violet base (0.1. Solvent violet 8 ((Metylviolet)
base) violet8)), 4253
5B crystal violet base (
0.1. Solvent Violet 9), 42555B (
Kristallviolettbase) Victoria Blue Base F4R (0.1. Solvent Blue 2), 42563B (Vikt.

riablaabaseF4R) Victoria Blue Base FB (0.1.Solvent Blue-4), 44045B Victoria Blue Base B
(0.1. Solvent Blue 4),
44045B Victoria Pure Blue Base FGA
(0.1. Solvent Blue 81) (Vikt
onareinblaubase FGA) Blue Base KG (0.1.Solvent Blue 84) (B1abase KG) Nigrosine Base LTK (0.1.
Solvent Plaque 7 (Solvent (Nigros)
inbaseLTK) black7)),5
0415B insulin base NF
(0.1. Solvent Blue 7), 50400
B Insoulin Base NR Nikron Base 0
(0.1. Solvent Black 7
), 504158 The mixing ratios of the individual solid components used in the electrophotographic liquid developer according to the invention may vary within a wide range.

However, the following proportions have proven to be particularly advantageous: 4 to 100 parts by weight, in particular 4 to 5 parts by weight, of polymer are used per 1 part by weight of pigment, with this polymer fraction including polymer protection. Colloids may also be included. The ratio of pigment to conditioning aid is about 1 part by weight to about 0.002 to 1 part by weight, especially about 0.02 to about 0.6 part by weight. The polymer effective as a protective colloid is used, in particular, in approximately the same amount as the polymer coating the pigment.

However, the concentration of protective colloid is approximately 0 per part by weight of polymer.
．． It may be between 1 and 2 parts by weight. The ratio of protective colloid polymer to dispersion aid is about 1 part by weight to about 0.01 to about 1 part by weight. As the carrier liquid, an organic liquid having high electrical resistance and low dielectric constant is suitable. This includes in particular aliphatic hydrocarbons with a boiling point range of about 120 to 2000C.
Quite particularly, hydrocarbons, such as Esso's Isopar (
Those known under the trade names of lsopa phantom sub G and day are suitable. Liquid developers according to the present invention generally have a
The dispersion contains solids in the range of about 5% by weight.

If necessary, the liquid developer according to the invention can contain a small amount of a solvent for the dispersing polymer. As a result, the tackiness of the polymer can be increased or optionally adjusted at room temperature by swelling the polymer in the electrically insulating liquid. Such solvents must be miscible with other additives, such as protective colloids. In this case, solvents which have already been used for this purpose are suitable. This applies in particular to aromatic hydrocarbons, halogenated hydrocarbons or esters and ketones. In particular, aromatic hydrocarbons having a boiling point range of about 160-1800C, such as Eso Bullpen (S
It has been found that ZOL-Vesso 100 strength, known under the trade name OL-Vesso (2008), is particularly suitable. However, in this case it is possible to operate with smaller amounts contrary to the known usage amounts. That is, the range of the amount of solvent added is approximately 0.3 parts by weight per 1 part by weight of the total solids. By adding a solvent, the adhesion of the toner to the photoconductor or recording paper can be varied over a wide range, the tack can be adapted to the desired purpose, and the addition of parentheses can be carried out at any time, thereby making it possible in accordance with the invention. The stability of the liquid developer is very significantly improved. In the present invention, at least one type of copolymer consisting of vinyltruol or styrene and acrylic acid or methacrylic acid ester is mixed with at least one type of pigment to form a solid substance, and the particles of this solid substance can be used in a conventional manner. In preparing electrophotographic liquid developers by dispersing them together with additives in an electrically insulating organic carrier liquid, the solids are homogeneously mixed in a solvent at a temperature of about 100 to about 20,000 °C, and after cooling. Characterized by grinding and then dispersion under grinding in an electrically insulating organic carrier liquid, in which the solubility of the solids increases with increasing temperature, at a temperature in the softening range of the solids, and then cooling to room temperature. The present invention relates to a method for producing an electrophotographic liquid developer.

In particular, the mixing is carried out at a temperature in the range of about 120 to 160 cubic meters and the grinding to a particle size of about 30 French meters or less is carried out. Dispersion in comminution is advantageously carried out at a temperature range of about 50 to 150°C. A temperature range of 70 to 90 oo has proven particularly advantageous. Thereby, all pigment particles are already to some extent surrounded by the polymer layer necessary for the required triboelectrostatic properties of the particles before they are dispersed in the electrically insulating carrier liquid. In this process, the partial solubility of the polymer in an electrically insulating carrier liquid is exploited when hot in order to obtain an organosol-like state, but no solvents with high solubility are used. During cooling, polymer fractions are precipitated which, under the action of the grinding forces, are very finely distributed in the carrier liquid and are unusable at room temperature. This makes it possible to produce a stable dispersion of colored polymer particles. The method according to the invention is therefore divided into the production of colored polymers and the dispersion of the polymers in electrically insulating organic carrier liquids.

For the production of colored polymers, powdered polymers or polymer mixtures and pigments or pigment components are mixed, the material is heated above its softening point and heated in suitable equipment, e.g.
Homogenize with a roller mill, extruder or kneader.

After cooling, the pigmented polymer mixture is ground to a particle size of about 30 mm or less. Carbon black is generally used as the pigment component, but all other known pigments or pigment mixtures can also be used. In addition to pigments, dyes or other additives which impart the desired electrostatic properties to the polymer, such as modifiers and dispersion aids, may also be incorporated into this mixture when hot. In particular, pigments such as Reflex Blue B (Reflexbla
uB)-C. 1.42765-, Alcohol-soluble Nigrosin (Nigrosin Spritlaeslic)
h)-C. 1.50420-1 or fat black (F
ettschwarz) HB or HBN-C・1・
Dyes such as 26150- may also be added. The copolymer used is selected from the viewpoint that it is at least partially soluble in the carrier liquid in which it is used when heated, but its solubility in the liquid when cooled is as low as possible. .

Preference is given to using copolymers which are subject to a certain swelling effect by the liquid at room temperature, which causes the polymer to become sticky. Included in this category are vinyltoluol or copolymers of styrene and acrylic residues. In particular, Bodyear Tire and Rubbe Co., Ltd.
rCo. ) manufactured by P1iolite (P1iolite■)
Vinyltoluol acrylate resins, such as those known under the trade name VTAC or VTAC-L, are suitable. As other additives, further non-pigmented polymers, copolymers or resins (which may be soluble in the carrier liquid) may be added to facilitate the subsequent dispersion in the electrically insulating organic carrier liquid. be done.

These include copolymers of styrene and butadiene, esters of polyvinyl alcohol, colophonium or aliphatic hydrocarbon resins. The dispersion of colored polymers is
It is carried out at a temperature that is within the softening range of the polymer.

Substances that also act as protective colloids in carrier liquids and (
or) It has been found that optionally dispersing aids as well as regulators may be added. However, such addition is discontinued if the colored polymer already contains substances. When using predispersed commercially available pigments, it has been found that the largely unknown substances used for predispersion have an adverse effect on the triboelectrification properties of the colored polymer particles. Pigment species that are not predispersed are therefore advantageously used according to the invention. Protective colloids and optionally dispersion aids are also advantageously added to the carrier liquid. For the dispersion of colored polymers, therefore, first of all the substances acting as protective colloids or dispersion aids are dissolved in a portion of the carrier liquid.

Next, for example, a melting machine, a dispersing machine or a perl mill is used.
Approximately 50 to 1
The powdery colored polymeric material is added to the carrier liquid at an elevated temperature in the range of 50° C. and optionally other pigments, dyes or substances that influence the triboelectric properties of the particles.
After adjusting the solution equilibrium between each component, the mixture is slowly cooled to room temperature while being triturated, and then the remaining amount of the carrier liquid is added in small portions to the droplet.

In this process, polymer components that melt when heated but are soluble at room temperature are precipitated in a finely distributed form depending on the polymer solubility in the carrier liquid, which must have very low solubility for these polymers. be done. This gives loose spherical particles with a diameter of less than about 12 m, in particular less than 5 French m, which particles are particularly suitable for toner dispersion. Due to the absence of solvents with high solubility according to the state of the art, these particles also exist separately from each other during storage. As the electrically insulating organic carrier liquid, one having high electrical resistance and low dielectric constant is used.

Particularly those belonging to this range have a boiling point range of about 120 to 200o.
It is an aliphatic hydrocarbon of o. In particular, the boiling point range is about 150~
180 qo or mixtures thereof are used, such as lsopar G and H from Esso. Toner concentrates having different solids contents depending on the purpose of use are prepared, for example, those containing 3 to 1 parts by weight of carrier liquid per 1 part by weight of total solids. Concentrates of this type can optionally be re-diluted to the desired concentration of developer by simply adding a carrier liquid. Another advantage of the method according to the invention is that the required adhesion strength can be achieved by optionally adding at the stage of the finished liquid developer, for example small and minute amounts of polymeric solvents which are miscible with the protective colloid. Another advantage is that it allows adjustment and therefore adhesion to the photoconductor or transfer material.

For adhesion, a maximum of 0.0% solvent per 1 part by weight of total solids may be used.
It has been found that adding 3 parts by weight is sufficient and that below this weight the adhesion can be varied within a wide range and adapted to the desired purpose. Suitable solvents include aromatic hydrocarbons, halogenated hydrocarbons, esters and ketones.

Especially aromatic hydrocarbons, especially boiling point range of about 160-180℃
For example, Solvess 100 manufactured by Ezo Co., Ltd. is suitable. The liquid developer or liquid developer concentrate produced by the method of the invention maintains its granular nature even over long periods of time and therefore has an extremely long shelf life, e.g. The finished liquid developer can be converted into a finished liquid developer by addition of liquids and additionally adjusted to the desired degree with respect to adhesion. The invention will be illustrated in detail by the following examples. Preparation of a colored polymer: Example A For the preparation of a colored polymer, 3.5 parts by weight (GT) of carbon black with an average particle size of 27 nm and a vinyltoluol/octyl acrylate copolymer (pulverized to about 1 grain size)
For example, Goodyear Tire & Rubber Co.
oodyearTireandR blood is rCo. ) and P1iolite (sold under the name VTAC).

This mixture is homogenized in a screw mixer at about 160 millimeters. After cooling, the material is crushed, ground in a mill and fractions of up to 30 mm are separated for the production of developer solids. Example B For the preparation of a colored polymer which also contains a modifier, it is processed analogously to Example A and homogenized at about 150 qo.

Carbon black 3.2 parts by weight Vinyl toluol/octyl acrylate copolymer
94.0 parts by weight Reflex Fluor B (
Refle (C.1.42765)
2.1 parts by weight Example C The following colored polymers are prepared after the process in Example B: Carbon black
3.2 parts by weight pinyltoluol/octyl acrylate combination 95
．． Tortoise weight part alcohol lacquer nigrosine (Ni needle oslnSprit
laeslich) (C.1.50420)1. parts by weight.

Example D For the production of a colored polymer containing a soluble polymer and a modifier, which simultaneously act as protective colloids, process analogously to Example A and homogenize at about 140° C.: carbon black 2. Part by weight of vinyltoluol/octyl acrylate copolymer
57.9 parts by weight styrene/butadiene copolymer, e.g.
llipsPetroleumCo. ) Solprene 1
205 (Solprene ■1205), 38. Weight part reflex blue-B (Refle Yulau B) 1.25
Weight part.

Example E Processing and homogenization are carried out analogously to Example A for the production of a colored polymer containing at the same time a dispersing aid.

Carbon black 6.0 parts by weight styrene/n-butyl methacrylate (70:30) copolymer, such as Rohm & Haas Co., Ltd.
asComp.

) made by Pararoid B-66 (Paraloid B-66
) 51. Part by weight aliphatic hydrocarbon resins, such as Esso-Chemi
eCmbH) Escorez 110 waves (Escorez■
110) 40.4 parts by weight polyvinyl stearate, e.g.
Polyvinyl stearate PVS-151. $ parts by weight Example F A soluble polymer that also acts as a protective colloid,
To prepare a colored polymer containing dispersing aids and regulators, it is treated analogously to Example A and homogenized at 15,000 °C.

Carbon black 3. Weight part Vinyl toluol/octyl acrylate copolymer
48.9 parts by weight styrene/butadiene copolymer 32.5 parts by weight colophonium ester, such as Hercules Powder Co.
erCo. ) Made by Pentaly H
14.2 parts by weight alcohol-soluble nigrosine (
NigroslnSpritlaesli-ch)
0. Mother weight part Example G 14 by the method of Example F
Homogenize at 5qo.

Carbon black 1. Red weight part vinyl toluol/octyl acrylate copolymer
55.4 parts by weight styrene/butadiene copolymer 37. Part by weight of polyvinyl stearate 4. Mother weight part Reflex Blue-B (Refle
lauB) (C.1.42765)
For the production of a highly pigmented polymer simultaneously containing 1.2 parts by weight of a soluble polymer which acts as a protective colloid, 140
Homogenize with 00: Carbon black 2
0. Part by weight of vinyl toluol/octyl acrylate copolymer 47. Mother weight part styrene/butadiene copolymer 32. parts by weight Example I For the production of highly colored polymers containing at the same time protective colloids and modifiers, process analogously to Example A and homogenize at about 155 oo: carbon black.
17. Part by weight: Vinyltoluornooctyl acrylate copolymer: 42.1 parts by weight Styrene/ptadiene copolymer: 28.8 parts by weight Reflex Blue-B (RefleauB) 11. Parts by Weight Next, a method for producing a liquid developer according to the present invention comprising the above-mentioned colored polymer will be explained with reference to Examples.

Comparative Example 1 A developer manufacturing experiment at room temperature is conducted as follows.

Styrene butadiene copolymer 5. The parent weight part is an aliphatic hydrocarbon, such as lsopar.
Dissolve in 4 parts by weight.

To this solution was added the colored polymer 9. obtained from Example A. and 2.4 parts by weight of Reflexblau AMFO.
．． Add 14 parts by weight at 2000 in a dispersion device. This mixture is ground in a ball mill at 20 o'clock for 3 minutes. Next, 42.2 parts by weight of Isopar G is gradually added while re-grinding.
It is confirmed that after addition of the entire amount of Isopar G, no dispersion is formed and a viscous rubbery substance is obtained. 0 The same ingredients as in Example 1 are used in the same proportions.

However, the vinyltoluol-octyl acrylate copolymer is not colored with carbon black before its use. Vinyl toluol/octyl acrylate copolymer 8
．． 7 parts by weight of lsopar day 20.15
Disperse together with parts by weight in a dispersion device at 80 qo for 5 minutes.

0.3 parts by weight of carbon black is then added to this mixture and dispersed for a further 5 minutes. Continued isopal day 20.1
Styrene/butadiene copolymer in 5 parts by weight5. Add part by weight of the solution and disperse for another 10 minutes, then knead into 2.4 parts by weight of Isopal and
MFO. 14 parts by weight were added. The mixture is milled in a ball mill at 80°C for 3 minutes, then cooled to room temperature and 42.4 parts by weight of Isopar G are gradually added while re-milling. 3 After grinding the powder, a liquid developer concentrate is obtained, the particles of which, in contrast to the toner according to the invention, are 60-90 mm.
has a diameter of Dilute the concentrate as in Example 1. In contrast to the toner according to the invention, extremely blurred copies are obtained.

Most of the toner image remains on the photoconductor and is not transferred to the paper. Furthermore, the dispersion stability of the toner is extremely low. m Treated as in Example U, but instead of carbon black, pre-dispersed commercially available carbon black such as Mikrolit from CiGei AG was used.
hschwarz) 21816TI. Use 6 parts by weight. Using the liquid developer obtained from this concentrate, Example 1
In contrast to the obtained developer according to the invention, speckled and rather blurred copies are obtained. Most of the toner image remains on the photoconductor and is not transferred to the paper. Example 1 Preparation of a liquid developer consisting of a colored polymer: styrene/butadiene copolymer, e.g.
．． ) manufactured by Solprene 12055.
Parts by weight of Tsuru are dissolved in 40.3 parts by weight of an aliphatic hydrocarbon having a boiling point range of 174 DEG to 191 DEG C., such as lsopar.

To this solution was added the colored polymer 9 obtained from Example A. and 2.4 parts by weight of Isopar.
．． 14 parts by weight are added at 80° C. using a dispersion device. Mill the entire mixture in a ball mill at 80 ooohs for 3 minutes. Thereafter, it is cooled to room temperature and 42.4 parts by weight of Isopar 0 are gradually added while re-milling. After milling for 30 minutes, a liquid developer was obtained whose particles had an average diameter of 5 mm and the largest particle was less than 11 mm.

Addition of 6 to 8 parts by volume of an aliphatic hydrocarbon having a boiling point range of 158 to 1770, for example Isopar G, to 1 part by volume of this concentrate yields a usable electrophotographic liquid developer.

This liquid developer develops a negative charged image obtained, for example, by charging and imagewise exposing a polyvinyl carbazole trinitrofluorenone photoconductor layer (1:1 molar ratio). Images with good sharpness and sharp contrast are obtained which can be transferred virtually perfectly to white paper by simply contacting them after removing excess developer. If desired, the tackiness of the colored polymer deposited on the photoconductor may be reduced by solvating it with an aromatic hydrocarbon having a boiling point range of 160 to 18,000, such as Solvesso 100 from Esso. It can be increased by adding

The amount added may be, for example, two parts per liquid developer.
However, ketones, such as methyl ethyl ketone, or esters, such as butyl acetate, or halogenated hydrocarbons swell the refractory polymers, thereby increasing their tackiness even in the presence of small amounts. Example 2 Process as in Example 1, but with reflex
e-statement! au) AMF substitute, oil acid and nigrosine base (Njgosi et al.) C or indiulin base (
lndulinase) N or indulin base NR
An equal amount of a paste of 3 wt.

In all three cases, a liquid developer having particles with an average diameter of 5 mm is obtained.

Copies obtained using these developers are excellent in size, sharpness, very good resolution and clean substrate. Example 3 The preparation of a liquid developer consisting of a colored polymer, which simultaneously contains a modifier, was carried out analogously to Example 1 using a styrene/butadiene copolymer, for example Sorprene 1204 from Philips Vetroleum, USA.
42.1 parts by weight Colored polymer "B" 9.9 parts by weight Isopar G 41. This is done using the same parts by weight.

Particles with an average diameter of 4mm are produced, and the finest particle is 1mm.
It is as follows. Polymer "C" can also be effectively used in place of polymer "B". EXAMPLE 4 The preparation of a liquid developer consisting of a colored polymer containing at the same time a soluble polymer acting as a protective colloid and a modifier was carried out according to example 1. Colored polymer "D" 16.1 parts by weight iso/Gur day 42.1 iso /Guru C 41.8.

The resulting developer is extremely fine. The average particle diameter is 3 m or less. Example 5 For the production of a liquid developer consisting of a colored polymer which also contains a dispersing aid, the following treatment is carried out: a vinyltoluol/octyl acrylate copolymer, for example Priorite V from Goodyer, Tyre & Rubber, USA.
5.5 parts by weight of TAC are dispersed together with 9.5 parts by weight of an aliphatic hydrocarbon having a boiling point range of 174 DEG to 191 DEG C., such as Isopar HI manufactured by Esso, in a dispersion apparatus at 80 DEG C. for 5 minutes.

Next, 9.3 parts by weight of colored polymer "E" are added and dispersed for an additional 5 minutes. Subsequently, an aliphatic hydrocarbon, such as a styrene/butadiene copolymer, such as Sorprene 12055, in 9.5 parts by weight of Isopar HI. 1 part by weight of the solution was added, dispersed for an additional 10 minutes, and then mixed with Isopal day 2. Flex Blue AMFO. Add 14 parts by weight. The mixture was milled in a ball mill at 80 qo for 30 minutes, then cooled to room temperature and remilled with Isopar G41. Gradually add parts by weight. After 30 minutes, a liquid developer having toner particles with an average particle diameter of 12 mm is obtained.

Example 6 A soluble polymer that simultaneously acts as a protective colloid,
Colored Polymer F 17. A liquid developer consisting of a colored polymer containing a dispersion aid and a modifier. $ parts by weight, aliphatic hydrocarbons with a boiling point range of 190-200 qo, such as Isopal L 41. Prepared according to Example 1 from 41.1 parts by weight of an aliphatic hydrocarbon having a boiling point range of 158-177q0, for example Isopal G.

The average particle diameter is 4.5 m. Example 7 Colored polymer "D" according to Example 4 16. Parts by weight of Isopar day 41. $ parts by weight Fatty alcohol polyglycol ethers, such as Wnapol S from Fw Hoechst
Isopal G with -0200.5 parts by weight added
41. A liquid developer is manufactured from 1 part by weight.

A fine liquid developer is obtained having an average particle diameter of 4 mm. For example, fatty alcohol polyglycol ethers such as Emulso M manufactured by Hoechst, fatty acid polyglycol ethers such as Emulsogen SG, or polyvinyl stearic acid esters also have the same effect as dispersion aids. have

Example 8 This example describes the use of a highly pigmented polymer containing at the same time a protective colloid and a modifier.

Vinyl toluol/octyl acrylate copolymer8.
21. and 80 qo in a dispersion machine for 5 minutes.

Next, add 1.8 g of colored polymer and disperse for an additional 5 minutes. Next is Isopar day 21. 5. parts by weight of styrene/butadiene copolymer. Add the neck weight solution. After further dispersion, the mixture is milled in a ball mill at 8000 for 3 minutes. Then cooled to room temperature and re-milled with Yisopar G41. Gradually add the mother weight parts.
After a further three millimeters of attrition, a liquid developer containing toner particles having an average diameter of 7.5 mounds is produced. Although the gist of the present invention has been described in the claims, many embodiments are possible, and these will be listed below. 2. The liquid developer according to claim 1, wherein the 1' polymer particles have a particle size of about lvm to about 5 fm.

(2) The liquid developer according to claim 1 and claim 1, wherein the polymer layer is made of or contains a polymer or copolymer that can be swollen by a carrier liquid.

'3} Claim 1 and 1 to 2 above, characterized in that the polymer layer is made of or contains a copolymer of vinyltoluol or styrene and an acrylic ester. Liquid developer described in section.

(2) The polymer layer is made of or contains a vinyltoluolnooctyl acrylate copolymer, and the claims 1 to 1 above.
Liquid developer according to item 3.

'5} Claim 1, wherein the polymer layer is made of or contains a styrene/n-butyl methacrylate copolymer, and 1 to 1 above.
Liquid developer according to item 3.

■ Claims 1 and 1 above, characterized in that the protective colloid contains a series of copolymers of butadiene and styrene, polypynylsthiarate, colophonium ester, or aliphatic hydrocarbon resin. ~5
Liquid developer described in section. {71 The liquid developer according to item 6 above, characterized in that it contains a copolymer consisting of 75% by weight of ptagene and 25% by weight of styrene as a protective colloid.

'8} Claim 1 and above 1, characterized in that it contains a fatty alcohol polyglycol ether or a fatty acid polyglycol ester as a dispersion aid.
7. The liquid developer according to item 7. (9} In addition to the pigment, Reflexful-B (Refle ground hawk)-C.1.4276
5-Alcohol-soluble nigrosine (NigrosinSp
rMoslich)-C. 150420-1 or fat black HB or HBN (Fe ratio sch rZ H
B or HBN)-C. 1.26150- and the above-mentioned claims 1 to 8.
Liquid developer described in section.

In addition to pigments, Reflexflu AMF-C. 1.4
2770:1 or Reflex Flu A Mother's Day. Claim 1, characterized in that it contains ○, and 1 to 1 above.
Liquid phenomenon agent according to item 8.

(11) Electrically insulating organic carrier liquid is about 120 to 200
C., in particular an aliphatic hydrocarbon having a boiling point range of about 150 to 19,000 C.

(12) Add 0.00% solvent for dispersed polymer to 1 part by weight of solid matter. The liquid developer according to claim 1 and items 1 to 1 above, which is additionally contained in an amount up to parts by weight of milk.

(13) The liquid developer described on page 12 above, which contains an aromatic hydrocarbon having a boiling point range of about 160 to about 180°C as a solvent.

3. A process according to claim 2, characterized in that the solids are mixed homogeneously at a temperature of IQ from about 140 to about 16,000 and, after cooling, are ground to a particle size of about 30 mm.

(15) The manufacturing method described in claim 2 and item 14 above, characterized in that the pulverized solid material is dispersed while being ground at a temperature of 50 to 150°C.

(16) In addition to the pigment, Reflex Fluor B (Re
fle karilatou)-C. 1.42765-, alcohol-soluble nigrosine. C. 1.50420-, or Fat Black HB or HBN (FettSchwarZ
HB or HBN) C.1.261501.

(17) A salt of a dye base and a fatty acid having 16 to 18 carbon atoms in a carrier liquid, Reflexflu AMF-C.
1.42720:1- or Reflex Flu A-G is added.

(18) The manufacturing method according to claim 2 and paragraphs 14 to 1 above, characterized in that up to 0.3 parts by weight of a polymer solvent per 1 part by weight of solid matter is added to the liquid developer at a base level. . (190) The method described on page 18 above, characterized in that an aromatic hydrocarbon having a boiling point range of about 160 to about 18,000 is used as the solvent.

Claims (1)

[Claims] 1 At least one copolymer of vinyl toluol or styrene and acrylic acid or methacrylic ester is mixed with at least one pigment to form a solid, and the particles of this solid are A method for producing an electrophotographic liquid developer comprising dispersing the solid materials in an electrically insulating organic carrier liquid, the solid materials being homogeneously mixed without a solvent at a temperature of about 100 to about 200°C, and after cooling. Grind, then soften the solid at a temperature of 50 to 150
A process for the production of an electrophotographic liquid developer, characterized in that it is dispersed under attrition in an electrically insulating organic carrier liquid, in which the solubility of the solids therein increases with increasing temperature, at 10°C, followed by cooling to room temperature.