DE2025752A1 - Benzobrasanquinone pigments and their use in photoelectrophoretic imaging systems - Google Patents

Description

Patent attorneys Dipl.-Ing. F. Weickmann,

Dipl.-Ing. H.Weickmann, Dipl.-Phys. Dr K. Fincke Dipl.-Ing. F. A. Weickmann, Dipl.-Chem. B. Huber

8 MUNICH 86, DEN

PO Box 860 820

MÖHLSTRASSE 22, CALL NUMBER 48 3921/22

■ 1 ■

H / Kn Case Z.372 (XD / 2531)

. XEROX CORPORATION,
Rochester, NY / USA

"Benzobrasanquinone Pigments and Their. Use in Photoelectrophoretic Imaging Systems ¹¹

The present invention relates generally to benzobrasanquinone pigments and particularly the use of these pigments in photoelectrophoretic imaging systems.

Recently, an electrophoretic imaging system has been developed which can be used to produce! Color images is capable and which photoconductive link component particles used. This procedure is detailed in the United States patents 3 384 565, 3 384 566 and 3 385 488

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ben. In such an imaging system, differently colored light absorbing articles are suspended in a non-conductive liquid carrier. The suspension is placed between electrodes, exposed to a potential difference and exposed with an image motif. As soon as these steps are completed, selective particle heating takes place in an image configuration, creating a visible image on one or both electrodes. An essential component of the system the suspended particles that need to be electrically photosensitive, and by interaction with one of the electrodes in the treatment with activating _f electromagnetic Stra & LIMG appear to be a sharp change of charge polarity undergo · In a monochromatic system uses single-color particles create a monochrome picture ₉ which corresponds to the usual black and white photography «In a polychromatic system the pictures are produced in natural color, since mixtures of particles of two or more different parbes -» each for McM of a specific one

Wavelength or a narrow wavelength range are "borrowed, used", Me PartjLkeX "which are used in this system, must be both intense, pure colors and high photosensitivity." The known pigments often lack purity and brightness high photosensitivity and / or less preferred correlation between the peak exerts spectral response near the photosensitivity peak, which is necessary for use in such a system »-

The invention has therefore sub "set _p" Siel ■ photoelektrö "phoretic Abbildungsverfakrea sm © Essaf £ © _s .. iÄ the photosensitive pigment particles benut
Eliminate defects.

The invention is concerned with aater
sensitive particle for the

Imaging systems, with the creation of photoelectrophoretic imaging processes capable of producing color images and with the creation of photoelectrophoretic imaging processes that use particles that are better photographic Photosensitivity and color qualities than the known pigments.

The above-mentioned objects as well as others are achieved according to the invention realized by the fact that - quite generally speaking - created an electrophoretic imaging process vird, which benzobrasanquinone compounds of the general Formula:

X _n

is used in which R _{7 is} one of the radicals UH, O, S or Se; each of the radicals R _1-6 denotes N or C, where 0-4 R denotes N;

each radical X one of the radicals alkyl, aryl, alkoxy, carboxylic acid, carboxylic acid ester, CH ₃ , CF ₅ , C ₂ H ₅ , NO ₂ , OCH ₅ , OC ₂ H ₅ , CH, SO ₂ NH ₂ ; CO ₂ CH ₃ , CO ₂ C ₂ H ₅ , SO ₂ NHC ₆ H ₆ , Cl, Br, F, I or H;

m is a positive integer from 0-10 when R _{7 is} £ NH and is an integer from 1-10 when R ₇ = HH; and"

η is a positive integer from 1 to 5. It was found, that this particular class of benzobrasanquinone pig-

009849/1890

ments of electro-photosensitivity or photomigration characteristics which makes them particularly useful for photoelectrophoretic imaging systems.

Although any compound from the class of the benzobrasanquinone pigments of the general formula described above can be used in photoelectrophoretic imaging systems, those compounds are preferably used in which X = H or OH-. m »1 or 2 / and 1 to 3 of the radicals R ₁ to R ₆ = N, since these materials have particularly pure color and high photosensitivity for use in photoelectrophoretic imaging processes. Optimal results are obtained when X = H or CH ,. The Benzobrasanchinonpigniente the present invention may contain other compounds are added to them for the purpose of raising awareness, acceleration ^ mm achieve synergistic effects or to otherwise modify their properties ^ the "

The compositions of the above SOrmel can be prepared by adding 2. ₈ 2-dichloro-1 _s 4 ~ naphthoquinone with an anilide or esters of Formels'

where E «means one of the best MH _s O ₉ S or Se % each of the Eeste R ^ g 1" or Q means ^ where- 0 to 4 E have the meaning Έ en ^

X each has one of the radicals alkyl _s Atj1 _s Elosejg carboric acid _t carbonic acid ester, ' CH ^ ₉ G ¥ ^ _f G ₂ H ₅₉ KO ₂₅ OCH ₃₅ , OC ₂ H ₅₉ CI ₉

SI ₉ GO ₂ C ₂ H ₅ / SO ₂ MHC ₆ Hg ₉ Gl ₉ Br ₀ I ₀ I or H loading

indicates;

m is a positive integer from 0 to 10 when R is " £ NH and is a positive integer from 1 to 10 when R-"MH; and

η represents a positive integer from 1 to 5.

The compositions produced with the above reaction have the following common characteristics: brilliant, intense yellow or orange color, insolubility in water, and in common organic solvents such as benzene, Toluene, acetone, carbon tetrachloride, chloroform, alcohols and aliphatic hydrocarbons; and unusually strong photosensitive reaction.

The use of the benzobrasanquinone pigments of the present invention in photoelectrophoretic imaging processes can be brought closer by the accompanying drawing, which shows an example of an electrophoretic imaging system will.

Now to the drawing: It shows a transparent electrode 1, which in this exemplary case consists of an optically transparent Glass layer 2 consists of a thin, optically transparent layer 3 made of tin oxide, commercially available called "NESA" glass. This electrode is hereinafter referred to as the "injection electrode" in Description led. The surface of the injection electrode 1 is more photosensitive with a thin layer 4 finely divided Particles dispersed in an insulating liquid carrier coated. The term "photosensitive" refers for the purposes of the present application to the properties of a particle which, once drawn to the injection electrode, under the influence of an applied electric field migrates away from it when exposed to actinic electromagnetic radiation. The detailed theoretical

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Clarification for the likely mechanism of the present invention is given in U.S. Patents 3,384,565,384 and 3,385,488, which are incorporated herein by reference. The liquid suspension 4 can also contain a sensitizer and / or a binder for the pigment particles which is at least partially soluble in the suspending or carrier liquid, which is described in more detail below. Lifting the liquid suspension is a second electrode 5, hereinafter referred to as "blocking electrode ¹¹ , which is connected to one side of the potential source via switch 7. Me opposite side of potential source 6 is connected to injection electrode 1, so that ₅ when the switch 7 is closed, an electric field is applied through the liquid suspension 4 between the electrodes 1 and 5. An image projector consisting of a light source 8, a translucent image (slide) 9 and a lens 10 exposes the dispersion 4 with a light image of the original slide to be reproduced 9. The electrode 5 is constructed in the form of a roller having a conductive central core 11 which is connected to the potential source β The core is coated with a layer of iron-blocking electrode material 12, which can be barite paper «The Pigmentsuspeiislos is exposed with i © asra reproducing image, while end a potential Wsex the lock · = and inject =. Electrodes is applied through the closing of the Iselialter 7. The roller 5 is allowed to roll over the inner side of the Injection Electrode 1 during the exposure time. This exposure veraslsi-fe ät® rosprüaglieli you of the electrode 1 sucked in ^ feelleM @ t © m g. the liquid zn \ ianäexn vmä mt & h au ü <bt ofeerfläcii © of the "SperrelektroSe f estsissetaea ^ i? @ l3 @ i mi® © is Pigaeatbilä - ataf the surface ier liijisierelelrfe® ^ © ziarlieklassem _s ^glIeh © ® a duplicate of the BrsgOTH fiiiieeiiselieineBoLea Biläss 9 ± i After exposure, äi © evaporates relatively volatile © carrier liquid uni leaves behind ias Pi @

image can then be pinned in place, for example by applying a thin layer on its top or with the help of a dissolved binding material in the Carrier liquid, such as paraffin wax or another suitable binding agent, which when the carrier liquid evaporates comes out of the solution. It has been found that about 3 to 6 weight percent paraffin binder in the vehicle gives good results. The carrier liquid itself can be liquefied paraffin wax or another suitable binder. On the other hand, however, the pigment image remaining on the injection electrode can also be transferred to another surface and be fixed on it. As will be explained in more detail below, this system can either produce monochromatic or polychromatic images depending on the type and those suspended in the carrier liquid Number of pigments and the color of the light with which the suspension is exposed in the process.

Any suitable carrier for the pigment articles in the system can be used insulating liquid can be used. Typical carrier liquids are decane, dodecane, n-tetradecane, Paraffin, beeswax or other thermoplastic materials, Sohio Odorless Solvent 3440 (one of the standard Oil Company of Ohio) and Isopar-G (a long chain, saturated, aliphatic hydrocarbon from the Humble Oil Company of New Jersey). pictures of good quality are generated with voltages in the range of 300 to 5000 volts with the device shown.

In a monochromatic system, particles become one single composition dispersed in the carrier liquid and exposed to a black-and-white image. This gives a single color, corresponding to the usual black and white photography. In a polychromatic system, the particles are chosen so that those of different Color to different wavelengths in the visible spectrum

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speak according to their main absorption bands. The pigments should also be chosen so that the curves of their spectral response sensitivity do not substantially overlap and thus permit color separation and the subtractive formation of multicolor images. In a typical multicolor system, the particle dispersion should contain cyan colored particles that are primarily sensitive to red light, magenta colored particles that are mainly sensitive to green light, and yellow colored particles that are mainly sensitive to blue light. If these particles are mixed together in a carrier liquid, they produce a black-looking liquid. "If one or more of the particles are caused" to migrate from the base electrode 1 in the direction of the upper electrode, they leave behind particles that produce a color, which of the The color of the incident light corresponds to exposure to red light, for example, causing the cyan-colored pigment to migrate, leaving the purple-red and yellow-colored pigments behind, which together produce red in the final image. In the same way, blue and green colors are reproduced by removing τοη yellow or “purple-red. When white light falls on the mixture, wand.ern all pigments and leave the color of white or transparen "th substrate" Without exposure all pigments remain, which together produce a sehwarses ³ Image ₀ This is one-ideale- technology for subtractive Golorabbilöuragp since the particles do not consist of a single component, but rather double the functions of finished film dye and photosensitive

is

The class of yellow and orange discussed above

der? @ rw © Bdtssig in iron one oäer more §fö AfeteliragssjsteB tibesTrasehesicl effective ·! tea good © Spektral® Asa © ps? © @ tilbirk @ ± t umä höh® Eto'fe © '= sensitivity leads to % n tefteöp teilliaatea Biliaa _e It is known that is £ in general a © ia © ii gyaala = -unä Ifegeiit

Pigment particles separate more easily from the three-part mixture and produce more vivid images than the usual yellow pigments; The new pigments of the present invention, however, have surprisingly good color separation and image density properties.

All suitable differently colored photosensitive pigment particles which have the desired spectral responsiveness, can be used together with the benzobrasanquinone pigments of the present invention to form a partial suspension to form in a carrier liquid for color imaging. It was found to be from about 2 to about 10 weight percent pigment deliver good results. The addition of small amounts (generally in the range from 0.5 to 5 mol $) of electron donors or acceptors to the suspensions, the Significantly increase system photosensitivity.

The following examples define and describe methods of making the compositions of the invention. if unless otherwise indicated, the parts and percentages represent parts and percentages by weight. The following Examples illustrate various preferred embodiments of the present invention intended to provide the However, do not limit the invention.

example 1

About 30 parts of 2,3-dichloro-1,4- * naphthoquinone are in 200 parts Isopropyl alcohol with about 35 parts of an anilide of the formula:

C-NH-CH ₂ O

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009849/1890

refluxed. About 42 parts of triethylamine are added dropwise with stirring over the course of about 1 hour. The refluxing is continued for about 1 hour, then the solution is filtered off while still warm. The product is then washed with isopropyl alcohol and recrystallized from dimethylformamide. About 16 parts of a yellow pigment of the following formula are obtained

Example 2

About 25 parts of 2,3-Mehlor-1 _f 4-naphthoquinone are about 25 parts of an anilide of the formula in about 200 parts of isopropyl alcohol kit:

boiled under reflux "About 55 parts of triethylamine are mm" drop by drop while stirring in the course of τοη for about 1 hour continue to reflux for about 1 hour, cool the solution

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to room temperature and the product is removed by filtration. The product is washed with isopropyl alcohol, about 16 parts of a yellow pigment of the following formula are obtained:

example 3

About 10 parts of 2,3-diehlor-1 _{liter of} 4-naphthoquinone are roughly
50 parts of pyridine with about 11.5 parts of an ester of the formula!

refluxed. Each, about 1 hour, the solution is cooled, the resulting precipitate is filtered off and washed with isopropyl alcohol washed. The product is recrystallized from dimethylformamide and about 8 parts of an orange color are obtained Ester pigment of the formula:

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009849/1890

Examples 4 to

Example 1 is repeated twice in succession using the following anilides

C ~ S- (CH ₂ ) ₄ -O

-NO,

(Example 4)

C-IH- (GH «5 ₀ - (' V-OCH

88 ti C. \ I.

(Example 5)

In each]? All- (Example 4 tani 5) yellow pigments are obtained with the following formulas

never

-NO,

in example 4

C-NH- (CHj O

in example 5

The following examples outline the present invention specifically., with regard to the use of the compositions of the general formulas given above in electrophoretic imaging processes. Unless otherwise stated is represent the parts and percentages by weight parts and weight percentages The following examples are intended to provide various preferred embodiments of the electrophoretic Illustrate the imaging method of the present invention "

The following examples are used in a device of the general

009849/1890

carried out of my type, which is shown in the drawing, with the imaging mixture 4 »It is applied to a * NESA glass substrate through which the exposure is carried out. The HESA glass surface is connected in series with a switch, a potential source and the conductive center of a roller that has a baryta paper coating on its surface. The roller is approximately 6.35 cm (2 1/2 inehes) in diameter and is moved over the plate surface at about 1.45 cm / sec exposed to a light intensity of 8000 foot candles, measured on the uncoated HESA glass surface. Unless otherwise specified _e are 7 wt .- # nnä suspended in each example in "Sohio Odorless Solvent 3440" of the pigments given the strength of the applied potential is 2500 volts. All pigments having a relatively large particle size in the production are, in a ball mill s 43 hour milled to reduce its size, so that a stable dispersion is obtained, which improves the resolution OCE final images. The exposure is carried out with a lamp of 3200 ⁰ K through a neutral step wedge filter with a density of 0.30 (0.30 neutral density step wedge filter) in order to increase the sensitivity of the suspensions to white light

Measure ψ , then Wratten filters 29 »61 and 47b are placed individually in separate tests over the] üelit« ps © lle in order to measure the sensitivity of the suspensions b® ± red ₉ green or blue light »

Example 6

Example J _{9 is} repeated using aaa © inen ester of the following formula:

00S848 / 1B90

-J5

An orange pigment of the following formula is obtained

Example 7

About 7 parts of the pigment prepared in Example 1 are suspended in about 100 parts of “Sohio Odorless Solvent 34-40”. The mixture is applied to a RESA glass substrate and a negative potential is applied to the roller electrode. The plate is passed through a Wratten 29 filter and a stepped gray wedge filter neutral density, which exposes the plate to red light. The pigment turns out to be completely insensitive to red light. The above The above steps are then repeated using Wratten 61, Wratten 47b and no filter to adjust the sensitivity to test against green, bluest and white light. The pigment is insensitive to green light, but equally sensitive to blue and white light. at

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The suspension possesses exposure to blue or white light good photographic photosensitivity and gives images of good intensity.

Example 8

A series of tests are carried out as in Example 7, supra, with the exception that the pigment here is that prepared in Example 2 Is carboxamide. Again it is found that the suspension is equally sensitive to blue and white light and insensitive to green and red light. The suspension has satisfactory photographic properties Photosensitivity and image intensity.

Example 9

It performs a series of tests as in Example 7, - above, by with the exception _s that the pigment comprises the orange ester prepared in Example 3 * Again, the suspension proves equally sensitive to white and blue light, but insensitive to green and red light. Good photographic photosensitivity and image intensity are found.

In each of the following examples, a suspension containing equal amounts of three differently colored pigments is prepared by dispersing the pigments in finely divided form in "Sohio Odorless Solvent 3440" in such a way that the pigments make up about 8 % of the mixture mixture may be referred to as "tri-mix" ,, the mixtures are tested individually, ind m @ they are applying to a glass substrate and HESA in example 7 above _{S s} exposed as with the exception that a Hulticolor- ,, ⁿ Kodacl) rome ⁿ -Siapo8ltiv- anstell®

40/1

the neutral density filter and the Wratten filter between the light source and the plate is placed. It therefore becomes a multicolored image projected onto the plate while the Roll over the surface of the coated NESA glass substrate emotional. A barite paper barrier electrode is used and the roller is maintained at a negative potential of about 2500 volts with respect to the substrate. The roller is passed over the substrate six times and cleaned after each passage. The applied potential and exposure are both maintained throughout the six passages of the roller. After finishing the six passages the quality of the image left on the substrate in terms of its intensity (density) and color separation rated. .

Example "10

The pigment mixture consists of: as a magenta pigment, Watchung led B, a barium salt of 1- (4 ^l -methyl-5 ^l -chlorazobenzene-2 ^l -sulfonic acid) -2-hydroxy-3-naphthoic acid, CI Ho. 15865, from Fa . DuPont; as the cyanine pigment Monolite Past Blue GS, the c & -porm of metal-free phthalocyanine, CI No. 74100, from the Arnold Hoffman Company; and the carboxamide prepared in Example 1 as a yellow pigment. This. Mixture of three when exposed to a multicolor image provides a full color image with excellent density "and good color separation.

Example 11

The. Pigment mixture consists of: as magenta pigment, locarno Red X-1686, CI No. 15865, i-U'-methyl-S'-chlorazobenzene-2 ^l -sulfonic acid) -2-hydroxy-3-naphthoic acid, from the

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American cyanamides; as a cyanine pigment, cyan blue GTNF, the ß-form of copper phthalocyanine, CI. No * 74160, from Collway Colors; and as a yellow pigment, that in Example 1 produced carboxamide. This mixture of three is exposed to a multicolored image and provides a complete picture Color image of excellent density and color separation.

Example 12

The mixture consists of a magenta pigment, llaphtho Red B, 1- (2'-methoxy-5 ^l -nitrophenylazo) -2-hydroxy-3 "-nitro-3-naphthanilide, CI No. 12355, from Collway Colors; a cyanine pigment , a polychlorosubstituted copper phthalocanine, CI · Uo. 74260, from Imperial Color and Chemical Company, and as a yellow pigment the carboxamide prepared in Example 4. This mixture of three is exposed to a multicolored image and provides a complete color image of good density and color separation.

Example 13

The pigment mixture consists of a magenta pigment, Vulcan Fast Red BBE Toner 35-2201 _s 3 * 5 ⁸ ~ dimethoxy-4,4'-biphenyl-bis- (1 "~ phenyl-3" -methyl-4 ^! '~ Azo »2 ^tI ™ perylen-5 "» - on), CI. No. 21200, ^ by Collway Colorsj a cyanine pigment Cyan Blue, 3 »3 ^β- methoxy-4,4'-diphenyl-bis-C 1 ^SI -azo-2 "~ hydroxy-3" -naphthanilide), CI. No. 2118Oj, from Harmon Colors; and as a yellow pigment from the pigment prepared in Example 5. This mixture of three is exposed with a multicolored image and provides a complete color image of good density and Color separation.

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Example 14

The pigment suspension consists of a magenta pigment, Inäofast Brilliant Scarlet Toner, 3,4,9,10-BiS- (Ii ₁ IP-P-methoxyphenylimido) -perylene, CI Ho. 71140, from Harmon Colors; a cyanine pigment Honolite Past Blue GS _{1 of} the Ot form of the metal-free phthalocyanine, CI Uo. 74100, from the Arnold Hoffman Company; and as a yellow pigment, the pigment prepared in Example 2. This mixture of three is exposed to a multicolored image and provides a complete color image of satisfactory density and good color separation,

As the above examples show, the class is benzobrasanquinone pigments of the present invention are generally suitable for use in electrophoretic imaging processes. Since their photographic photosensitivity, density properties and color properties vary, a Mixture of special pigments preferred for special purposes be. Some properties of the pigments can be achieved through special cleaning processes, recrystallization processes and Dye sensitization can be improved.

Although specific components and proportions in the The examples described above can also be used with other suitable materials than those given above with similar Results are used. In addition, other materials can also be added to the pigment compositions, to achieve synergistic effects, accelerate or otherwise modify their properties. The pigment compositions of the present invention may or may be dye sensitized if desired can be mixed with other photosensitive materials, both organic and inorganic.

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Also other modifications of the present invention, which suggested to the skilled person reading the present specification bite .werden belong to the scope of the present invention,

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Claims (1)

ΡΑ1ΒΙΙΑΪ8Ρ ODOR: Benzobrasanquinone pigments of the general formula / R wherein R "denotes one of the radicals NH, O, S or Se; * each of the radicals R ^ _-6 denotes N or C, where 0 to 4 R denotes If; X each has one of the radicals * alkyl, aryl, alkoxy, carboxylic acid, carboxylic acid ester, CH ,, CP ,, CpHc »HO« »OCH», ÖCgHe, CiT, SO ₂ NH ₂ , CO ₂ CH ₅ , CO ₂ O ₂ H ₅ , SO ₂ NHC ₆ H ₆ , Cl, Br, V, I and H means m is a positive integer from 0 to 10 when R ₇ / £ NH and a positive integer from 1 to 10 when R «« NH; and
η represents a positive integer from 1 to 5. 2. Pigment according to claim 1, characterized in that X has the meaning H or CH- or comprises mixtures thereof. Pigment »according to claim 1, characterized - 21 - 00984971890 draws that X has the meaning H. 4. Pigment according to one of Claims 1 big 3 da characterized by that m »1« 5 «~. Pigment according to © in®® egg spray 1 to 3 »characterized in that m = 2« 6. Γ Pigment aadbi © to®m ier Ansprteli © 1 rock 5 ₉ . characterized ₉ that 1 to 3 times dissolved IL to Ig have the meaning N. 7. Method of manufacture
ments of the general rules of claim 1 _9, characterized in that 2.3 "DIELIOR ^ Is, 4 ~ naplithocliinom, bit of a compound is converted which has the following general formula? where H- means one of the radicals HH, 0, S or Se!
each of the radicals * R ₁ Jg denotes N or C, where 0 to 4 R denotes N; X in each case one of the radicals alkyl, aryl, Al & oaqr, carboxylic acid, carboxylic acid ester, CH ₃ , CF ₃₉ C ₂ H ₅ , UO ₂ , OCH ₃ , OCgH _{5 9} GM ₉
SO ₂ NH ₂ , CO ₂ CH ₃ , CO ₂ C ₂ H ₅ , SO ₂ NHC ₆ H ₆ , Cl, Br, E ₉ I or H ;. m is a positive integer tone 0 to 10 feeiewfettp if H is ₇ / IH and a positive integer yob I 009849/1890 ■ NHs and
η represents a positive integer from 1 to 5. 8 · Electrophoretic imaging process, thereby characterized in that a layer of a suspension is applied to the action of at least one between two electrodes Electric field is subjected and the suspension simultaneously with an image of activating electromagnetic Radiation is exposed, whereby a pigment image, which consists of migrated particles, at least one of the electrodes is formed, the suspension being a plurality of finely divided particles of at least one color and the particles of this one color contain a benzobrasane * Ehinon pigment of the general formula of claim 1 include »·. 9. Method according to claim 8, characterized in that at least one of the electrodes is at least partially is transparent and the suspension is exposed to the image through this transparent electrode. 10. The method according to claim 8 or 9, characterized in that that at least one of the electrodes has a Blocking electrode is. ' 11. The method according to any one of claims 8 to 10, characterized in that the suspension is a plurality of fine contains distributed particles of at least two different colors in an insulating carrier liquid, and the Particles of each color contain a photosensitive pigment, the main light absorption band of which essentially corresponds to its Main photosensitivity response. 12. The method according to any one of claims 8 to 11, characterized - 23 - 009849/1890 that X is H or CH, or comprises mixtures thereof. 13 · The method of any of claims 8 to 11 in _S by the fact that X = H. 14. The method according to any one of claims 8 to 13 »characterized in that m s 1. 15 · Method according to one of Claims 8 to 13 »thereby characterized that m = 2. 16. The method according to any one of claims 8 to 1.5, characterized in that 1 to 3 of the radicals R ₁ to Rg have the meaning N. - 24 - 009849/1890