DE2322704A1 - PROCESS FOR THE PRODUCTION OF DYE IMAGES - Google Patents

Description

AG FA-G EVAERT AG

PATENT DEPARTMENT

LEVERKUSEN

Process for making dye images.

The present invention relates to a process for the production of dye images by means of electrostatic means generated powder images.

From British patent specification 947 479 a method is known to form a fixed, visible image of an electrostatic latent image on a support. After that, a temporary powder image by powder development of the latent image on the support or by powder development and more imagewise Transferring the powder or a layer of the powder; verse generated on the carrier without fixing the powder on the carrier. Then the uncovered areas of the das Surface of the carrier bearing the powder image, made visible and finally the powder is removed.

It is an object of the present invention to provide a recording method to create in which a temporary powder image is produced by electrophotography, which as Mask is used to cover underlying parts of the recording layer shield from active electromagnetic radiation, under whose effect a directly visible or optically developable, latent dye image is created.

Another object of the present invention is recording materials to create that make the fixing of a powder image on the recording medium superfluous and which make it possible to produce visible dye images with the materials which are completely resistant to abrasion.

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The present invention can be used as a modification of the invention which is described in British Patent 947,479, as the layer or support, whereupon the powder image is formed or transferred, a color-forming, Contains photosensitive mixture, thus in the area that is not shielded from light by the powder image one or more dyes are formed.

A photosensitive recording material for the invention Use contains or in a recording layer a recording sheet made by exposure to active electromagnetic radiation produce a visible color:

(A) a photoconductive compound constituting the recording layer or recording sheet for electrophotographic Makes recording suitable,

(B) at least one dye precursor or a mixture of dye precursors, which form one or more dye substances when they are in active relationship with one photoexposed polyhalogen compound generating photo radicals stand

(C) a photosensitive polyhalogen compound produced by exposure to light generated with active, electromagnetic radiation, e.g. UV radiation, photo radicals.

The use of photosensitive polyhalogen compounds, which react with arylamines to produce print-out images, for photographic processes is already by R.A. Fotland in J.Phot.Sei., 18 (1970) 33-37, and in U.S. Patent 3,042,515.

Other dye forming systems based on the use of Photosensitive, organic polyhalogen compounds that generate free radicals are disclosed in US patents 3 102 810, 3 328 744 and 3 377 167 and in British patent

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registrations 41 749/70, 42 802/71, 48 804/71 and 40 349/71 been.

Photoconductive recording layers according to the present invention Invention preferred are able to work in the dark hold back an electrostatic charge. Your guiding

2 ability increases by at least a factor of 10 and preferential

wise by more than 10 when exposed to electromagnetic radiation.

The photoconductive compounds used are preferably compounds having a color that contrasts with the color of the formed dye image. Preferred inorganic photoconductors for this purpose are photoconductive zinc oxide, cadmium sulfide and cadmium sulfide selenide.

However, the recording layers preferably contain organic ones Photoconductors that can be used to produce recording layers that are transparent to visible light.

Such recording layers are not only used because of their transparency, but also because of their flexibility, - ' their ease of application and their sensitization preferred. , -

Many organic compounds have become known which have photoconductive properties. Among these substances are both monomeric and polymeric compounds. If they have layer-forming properties, then organic Photoconductors without an insulating binder can be used, although they are normally used as a solid solution or dispersion in resin or wax, which serve as binders, are attached.

Binder-free, polymeric photoconductors such as halogenated derivatives of poly-N-yinylcarbazole are useful in xerography Application found.

Solid solutions in a binder of monomeric, organic photoconductors in which atoms or groups of different

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Electron affinity are linked by a conjugated system, are specially designed for making iron photoconductive record * - materials suitable. Examples of such organic photoconductors are: 2,5-bis (p-diethylaminophenyl) «1,3,4-oxadiazole, 2,5-bis (p-diethylaminophenyl) -1,3,4-triazole, 2,4,5,7-tetranitro-9-fluorenone, the quinolone-2-quinolone-4 compounds, which are described in Belgian patent 7 ^ 7 84-9, and the Dihydro and tetrahydroehinoline compounds described in US Pat German patent applications P 21 59 804.9, P. 21 60 873 · 1 and P 22 54 573-9.

The above polymeric or solid solution films of organic photoconductors are grainless and substantial transparent to visible light. They can be used in the usual xerographic way, which means that they can be charged, exposed and developed with a toner. In the present invention, fixing is used of the toner on the film surface is omitted.

In a preferred embodiment of the present invention these photoconductive layers contain the above-described photosensitive dye-forming mixture containing the compounds Contains (B) and (C).

The amount of compounds (B) and (C) in the photoconductive Layer can vary widely and depends' on the density of the desired Color image.

Suitable recording layers contain, for example, 10 to 70% by weight of photoconductors,
2 to 20% by weight of the compound (s) (B) and 5 to 40% by weight of the compound (s) (C).

Preferred weight ratios of photoconductor to dye precursor or dye precursor mixture are between 20s12 and 20: 1.

The process of generating a dye image in the photoconductive Recording layer or the photoconductive one Recording sheet bearing a conductive backing layer,

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or the (that) "during exposure in contact with a conductive Material consists of the following steps:

- (1) Formation of an electrostatic latent image on the

Layer or sheet, ■ -,

- (2) Formation of a temporary powder image by clicking on the

Layer or sheet of electrostatically attractable, solid Applies particles,

- (3) Uniform exposure of the surface bearing a powder image to active electromagnetic radiation, which in the recording layer or the sheet creates a visible Färstoffbild.oder a latent image that can be optically developed into a dye image that corresponds to the areas that are not covered with the particles, corresponds to, ι

- (4 ·) Remove the powder image after the visible dye image or the latent image has been created.

A preferred combination of photosensitive polyhalogen compound (Compound G) and dye gate product (Compound B) contains in an intimate mixture:

(1) at least one spiropyran compound and

(2) at least one UV-sensitive compound that is involved in Exposure to UV radiation with the spiropyran compound a dye salt with a pyrilium or indolinium salt structure forms.

Preferred colorless dye precursors which are suitable for photographic image production according to the present invention are spiropyran compounds which contain at least one pyran ring which, in the ortho and meta position to the oxygen atom, is a condensed benzo, naphtho or other substituted or unsubstituted, carries higher, aromatic, polycyclic, condensed ring system, such as is present, for example, in a spirodibenzopyran, a spirodinaphthopyran, a spirobenzonaphthopyran, a 1,3,3-trimethylindolinobenzospiropyran, a 1 _t 3i3-irimethyliadolinonaphthQspiropyran or those spiropyranens which have an aromatic kylopyran nucleus of the anthracene or phenanthrac type. In these

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Spiropyrans can be the pyran rings, the condensed benzor rings, the fused-on higher, aromatic rings as well the 1,3,3-trimethylindoline ring may be substituted.

Suitable substituents for this are, for example, hydrocarbon groups such as alkyl groups, for example lower alkyl groups such as methyl, substituted alkyl groups, for example halogen- or phenyl-substituted alkyl groups, alkylene ester groups, for example a -yCHp-COOCgHr group, alkylene carboxyl groups, for example a -CHp-COOH group _? Alkylene carbonamide groups or those with substituted carbonamide groups, for example a -CH ^ COITH- <ζ Ζ? & Group, an acyl group, for example acetyl, a halogen atom, nitro, hydroxy, an alkoxy or aryloxy group or a substituent that contains the carbon atoms 3,3'-position in the spiropyran system binds together, for example · a (GH ₂ ) _n chain, in which η 2 or 3 denotes.

General formulas that include particularly suitable spiropyrans are as follows: _Λ -

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in it mean:

E, E ^, E ¹ ^ j, Eg, E'g, E, and E ¹ , each hydrogen, an aliphatic group or a substituted, aliphatic group, 2.B. a C ^ -Corf-alkyl group, a substituted C ^ -C ^ -alkyl group, in particular methyl, ethyl, propyl, amyl or hexadecyl, or a halogenated alkyl group, an alkylene ester group, e.g. a -CHo-COOCpHc group, an alkylene carboxyl group, ζ, · Β. a -CHp-COOH group, an alkylene carbonamide group or such a group in which the carbonanride group is substituted, for example a -CHp-CONH- ^ 2 ^ »group, an acyl group, halogen, nitro, hydroxy, an alkoxy or aryloxy group , a phenyl group or a substituted phenyl group, piperidyl or E ^ and E ¹ ^ together represent a - (CH ^^ - chain, where η is 2 or 3, to bond the carbon atoms in the 3 and 3 'positions together.

Suitable spiropyran compounds and their preparation are described in German Offenlegungsschrift 1,269,665, 1,2-4,655, 286,110, 1,286,111 and 1,286,112, in J.Prakt.Chem. (2) '114 , 18?

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(1926), in J. Am. Chem. Soc. 216288 (1952) and in J. Chem. Soc. (1934), 1571.

Preferred spiropyran compounds are spirodinaphthopyrans and SpirobeLfconaphthopyrans, their jfaphtho- and / or benzo ring or -Rings substitutes his kb'nnett.

A compilation of particularly useful spiropyran compounds is given in the following label 1;

Table 1

Spiropyran compound

Melting point (° C)

1.

2.

H C-OH-CH

OPQP

CH.-COOH

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257 204

208

185 164

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20th

H »£ .CH ₃

V:

21.

22nd

24.

H_C! CH_ 3 X _0/3

CH ₅

206

180

> 260

173

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2,322 J_D 4

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2121Ί3Α

112

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222Z1J1U

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To the production of the Spirobi (arylopyran) compounds and the Spiro (indolinoarylopyran) compounds in detail To illustrate, the following production examples are given. - ■, "

Manufacturing 1

Hersjtel.lung of 2 ^- M ^e i ⁿ Z ^ Z ^ i (£ ~ S ^a £ ^ i ⁿ £ ^s J £ ^ £ ⁰ £ y £ ^a S) X ^ £ ^r ^ - ^ £ ^} i ⁿ £ + 2. from table Y)

Into a 2 liter three-necked flask fitted with a reflux condenser and a tube that extends almost to the bottom of the flask for the gas supply are introduced:

Ethanol · ■ 1 liter

Butanone. 22 ml (0.25 mole)

2-hydroxy-i-naphthaldehyde 86 g (0.5 mol)

The flask is shaken until the additives are partially dissolved. Dry hydrogen chloride gas is introduced so that it is completely absorbed and the beginning of the ethanol reflux * Thereupon the already strongly blue colored reaction mixture is in a mixture of ice and sodium chloride cooled and the addition of hydrogen chloride gas up to Saturation continued. Are green pyrylium salt crystals formed in the reaction mixture? one sets the crystallization overnight in a refrigerator.

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The pyrylium salt formed is filtered off with suction and washed with ethanol and then suspended in 300 ml of ethanol.

A 10 wt .- $ aqueous ammonium hydroxide solution is under Stir added until the mixture is finally alkaline. The mixture becomes colorless.

The crystalline product obtained is filtered off with suction, washed with water, washed and dried.

Finally recrystallized "the spiropyran of 600 ml of benzene, separated again and dried under reduced pressure at 50-60 ⁰ C. Yield: 4-5 g. Melting point: 204- ⁰ C.

Manufacturing 2

Manufacture_; von_1 _a 3 _A 3-Trime ^

i)

The following ingredients are introduced into a 100 ml flask equipped with a reflux condenser: salicylaldehyde · _v -, - 3.7 g (0.03 mol) 1,3,3-trimethyl-2-methyleneindolamine 5.1 g (0.03 mol) ''"'ethanol 90 ml

The solution is refluxed for 2 hours, then cooled and filtered.

The filtrate is used to separate a solid product Given water. The solid product is filtered off with suction, washed with water and dried under vacuum.

The spirane compound obtained is recrystallized from 15 ml of hexane. . 'Yields 5 g. Melting point: 93-94 ⁰ C.

It is believed that by exposure to electromagnetic Radiation forms a dye salt, das.die Pyryliumstruktur has when a spirobi (arylpyran) compound is used as a dye-off precursor, and that when a spiro (indoline, arylpyran) compound is used, a dye is formed which has the indolinium salt structure.

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Other "preferred, colorless paraffin precursors for use according to the invention correspond to one of the following, general formulas (I) 'or (II):

J-CH = C (-C-) ^, (I)

³¹ - I 0

OH

ο ό;

OH

(II)

in which "mean:

E _x , an organic group, for example a saturated or unsaturated, aliphatic group, for example an optionally substituted alkyl group or optionally substituted aryl group, or together with E ¹ the atoms necessary to form a homocyclic group. see input to close, e.g. a cyclohexylen-2-one input,

E 'is hydrogen, a lower alkyl group such as methyl or a substituted lower alkyl group such as benzyl, a phenyl group or a substituted phenyl group or phenyloxy,

Z / | the atoms necessary to make a homocyclic input or to conclude a homocyclic ring system that substitutes both may be, for example, a phenyl group, a naphthyl group or those groups which, in addition to the hydroxyl group have one or more substituents, for example a methoxy group or a benzyl group, which are further assigned with a Hydroxyl group and a -CH = ΟΗ-ΟΟΕ ^ group is substituted, where E ^ has the meaning mentioned above,

Zg the atoms necessary to make an optionally substituted to close homocyclic nucleus, e.g. one optionally substituted benzene or a naphthalene nucleus,

E _{2 is} a lower (C ^ -Cc) alkyl group, and η 1 or 2.

The following table 2 contains a list of compounds according to of the general formula (I) and their melting points.

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- -18 -

Table 2

Number of
link

Structural forms1 Melting point ⁰ G

,

-OH = OH-OO- -OH

-CH = OH-COCH

0 ^:

0OH,

-CH = OH-COOH

, -CH =, I-OH

0 H

U-OH

r- J \ -CH = CH-COCH,

* Λ-0Η

, -CH = OH-CO-CH = CH-

-CH = CH-CO- -OH

155

105

130

83

177

227

139

127

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CH = C-CO-CO-CH = CH L

^ -CH = CH-CO-CO-CpH _n -LjI-OH * ^ρ

0-CH = CH-CO-C ^ H. -OH ⁶¹

CH = C-CO-CH _x

0
I.

-OH

- ^0H

CH u

CH

OCH

CH κ

CH I

-CH = CH-CO-

-CH = CH-CO- «f- V.

OCH,

CH,

OC
- <

S, \ -CH = CH-CO- -OH

V-CH = CH-COCH LvJJ-OH

> 200

160

- 74 153

> 200

250

115

115

139 200

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20th

Homopolymer containing repeating units represented by the following formula

-I CH ₂ -CH-

OH COCH = CH-

The production; of the compounds of the general formula (I) is described e.g. by:

Heilbron. And Whitworth, J. Chem. Soc. 1_23, 243 (1923), CD. Harries, Ber. 2J-, 3180 (1891 ") and Decker + V. Fellenberg, Ann. 364» ²¹ 0909).

A suitable compound according to the general formula (II) has the following structure: ^v

Their manufacture can be carried out as follows:

In a 250 ml flask fitted with a reflux condenser and a Gas inlet pipe, the latter reaching almost to the bottom of the flask, are introduced: 2-hydroxy-1-naphthaldehyde 10 g

Acetone 50 ml.

The flask is shaken until a solution is then obtained dry hydrogen chloride gas is introduced for 15 minutes, while the flask is chilled in ice water.

The reaction mixture is then left at room temperature for 24 hours held. The dark green solution obtained is poured into 200 ml of water. A sticky, green product separates away. The overlying water layer is removed and

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the residue is treated with 50 ml of methanol, the residue solidifying. The solid substance obtained is pulverized, washed again with 50 ml of methanol and dried. Yield: 9 g. Melting point: 200 C.

The compound 20 of Table 2 is produced as described in German Offenlegungsschrift 22 44 783

Another suitable dye-forming photosensitive composition contains in mixture:

(1) at least one organic polyhalogen compound of which a halogen-containing radical can be separated photolytically, whereby an acid H-X can be generated in which X halogen means

(2) at least one indolizine derivative that of the following general ones formula (III) corresponds to:

H ₁

SOLVE

in which:

Z the atoms necessary to create a fused, 6-membered, heterocyclic, nitrogen-containing ring that has two double bonds, or to close such a ring, the Is part of a fused, polycyclic ring system, this ring or ring system being substituted can, and

R / |, Rg and B.-Z (identical or different) each hydrogen, an alkyl group, or substituted alkyl group, an alkenyl group, an acyl group, a nitro group, an aryl group, a substituted aryl group, e.g. phenyl or a substituted phenyl group, where at least one of the substituents R 1 or R 1 is hydrogen, and (5) at least one aldehyde or aldehyde derivative of one of the following

Types:
(i) an aldehyde which contains a primary, secondary or tertiary amine group, e.g. a di alkyl amino group which is bonded to the aldehyde group through a conjugated system,

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(ii) a hydroxy aldehyde its hydroxyl group and aldehyde group linked by a conjugated system, and derivatives of such a hydroxyaldehyde $ in which the hydrogen atom the hydroxyl group through a metal atom or an alkyl group has been replaced, and those derivatives in which the aldehyde group has been masked, e.g. as an acetal group.

The following Table 3 is a list of suitable compounds according to the general formula (III) with their melting points and a reference for the preparation.

Table 3 -

No. of ^E 1 H H R ₂ Cf-H _R. 3 Enamel synthesis ^: ' Connect I. NO ₂ C. Point British patent font manure H H P-CN-C ₆ H ₄ CH, 658 560 1 ^C 6 ^H 5 ^G 6 ^H 5 P. 96 idem H CH,
P. CH,
ρ British Patent Script
999 874 CVI ^C 6 ^H 5 H 181 J.Chem.Soc. (1946) 3 H H 115 1069 4- H ^C 6 ^H 5 58 idem H ^C 6 ^H 5 H idem 5 " H CH, COCH ₅ 214 idem 6th NO ₀ P. COCH,
ρ 83 idem 7th C. CH ₅ COC ₆ H ₅ 64 J.Chem.Soc. (1946) .- 8th P-NO ₂ -C ₆ H ₄ H 137 1077 9 CH, 154 idem P. NO ₂ idem 10 H 103 Chem. Ber. 60, 1607 11 CH,
P. 235 (1927) ■ "■" ■ · 12th 36

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Tables 4, 5 and 6 are examples of suitable aldehydes of type (i) listed with their melting point; a hint for their synthesis is given *

Table 4

I '

E ¹

E ¹

.-CHO

No. of
link / * ΊΤΤ
V ^ / J ^ - E ' _a . CH,
3 Enamel
point, ⁰ C synthesis 1 / "ITT CH ₂ -CH ₂ -CN 75 Org. Synth. J53_,
27 (1953) 2 CH ₃ CH ₂ -COOCH ₅ 72 made ana
log precede
the hint 3 CH,
3 CH ₂ C (CH ₅ ) _{2 NO 2}
co _{> s} ^^^ _s ^ 72 idem. 4th
5 H H 98
173 idem
idem 6th 71 idem. -

Table 5

or E ₁₅ = -CHO

-E,

■ 13

No. of
Connect
manure «11 CH ₅ E ₁₅ H E ₁₅ Melting point
⁰ C synthesis 1 C ₄ H ₉ CHO CH,
3 Boiling point 115 ⁰ C /
0.2 mm Hg manufactured
analogous to
Org.Synth., CH ^ H XT956) 2 ° 6 ^H 5 CH,
3 CHO H CH ₅ 90 idem 3 C ₂ H ₅ CHO CH,
3 86 idem

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Table 6 '. "" I. N
ρ ^RI 12 Melting point
⁰ C - * '11 P-Gl-C ₆ H ₄
CH, 137
130 synthesis CH, 11 manufactured analog
to Org.Synth., 36,
74 (1956)
idem No. of
link pR _'12
i-CHO 1
2

Suitable compounds, which were described under (ii), are e.g. NaO- (CH = CH) P-CHO, prepared according to P.Baumgarten, Chem.Ber.

, 1624 (1924) and H ₅ C ₂ 0-CH = GH-CHCqc2 ^H .5> manufactured according to RWPrice,

^25th

₅ C ₂

qc2. ²

A.Moos, J.Amer.Chem.Soc. 6_2, 207 (1945)

Suitable organic polyhalogen compounds, one of which is a ^ halogen-containing radicals can be separated photolytically, correspond to the following general formula:

where A, B, X and Y each represent a halogen atom from the group chlorine, bromine or iodine, or

one of the symbols A, B, X or Y is an alkyl group of the one substituted Represents an alkyl group, e.g. pine halogen-substituted Alkyl group, a hydroxyalkyl group or an aralkyl group such as benzyl, a quinoxaline group, an aryl group, a substituted one Aryl group or an aroyl group and the other symbols chlorine, bromine or iodine, or at least two of the symbols A, B, X or Y represent an aromatic acyl group, e.g. benzoyl, and the other symbols represent chlorine, bromine or iodine.

Suitable representatives of this general formula are organic halides, such as carbon tetrabromide, bromoform, iodoform, hexachloroethane, hexabromoethane, pentabromoethane, 1,1,2,2-tetrabromoethane, ^., • ^ -tribromoacetophenone, tribromoethanol and those described in Belgian patent 757 145 2-tribromomethylquinoxaline compounds.
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Without thereby departing from the scope of the present invention in any way Way to delimit, it is believed that the color-forming reaction between the indolizine derivative and an aldehyde from Type (I) takes place according to the following reaction scheme:

(1) CBr ₄ + hf * CBr ₅ * + Br *

(2) Br * + EH (e.g. binder) * HBr + E * (organic

τ, '-ο -lEadical)

Br "

(5) 7 r ti ~ "-O j. TT ^- Rt. Λ 7 * *«,

(D *

(4) (II) + O = C- ^ tT *> - Kv °
H ^ - ^ ^X CH _X

Z, f? - ^E 2 _Γττ Br " ⁺ 3

The above-mentioned photosensitive, organic polyhalogen compounds are normally only in one wavelength. Sensitive range between 400 and 250 nm.

The photosensitivity of the dye-forming agents used in the present invention Compositions can be increased and spectrally increased if they are mixed with a sensitizing agent the compound used in the Belgian patents 771 848 and 786 973.

When using organic, spectral sensitizers, e.g. * Merocyanine or Styryi dye salts, which in their structure a conjugate system of sufficient length haban, so it is possible to adjust the spectral sensitivity down to the spectrum of the visible light and even * into the infrared range «

H-vinylearbazole polymers are particularly suitable for sensitization and copolymers that can serve as binders, MicHer's ketone, styryl dye bases, e.g. 2-Cp-Di-

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methylaminostyryl) -quinoline or 4- (p-Mmethylaminostyryl) -quinoline and photoconductive zinc oxide. .

The photosensitive recording layer can be used as a further component according to the present invention contain a film-forming binder.

Particularly suitable binders for use in accordance with the present invention Invention are hydrophobic polymers and copolymers, e.g. styrene, vinyl acetate, acrylonitrile, acrylate, methacrylate or butadiene units, hydrophobic cellulose derivatives, phenoxy resins or polycondensates of the polyester type, e.g. polycarbonates, and sensitivity enhancing compounds such as polymers containing N-vinyl carbazole units.

These binders, which serve as binders, can be used for improvement mechanical strength or adhesiveness of the recording layer to its support can be used.

In order to reduce the rate of spontaneous thermal color formation as it occurs during storage or during processing of the photographic materials over long periods of time, so-called anti-fog agents can be added to photosensitive compositions. Suitable anti-fog agents include triaryl compounds of elements of group V of the feried system, .2.B * irlphenyls.tibine and sterically hindered'fhinöle> i * B * 2, i "Dl" tert * "but" yl "p-ereeöl * friphenyl * • stlbin and altered connections zsus * inventive flasks apply in the bFitehen fatentsehrift 1 Ö71 1Ö4 fe

line dry, photographic visualization which contains the constituents , -can have an effect formed by dissolving the binding agent in a suitable inert additive, which serves as a dispersing or solubilizing medium for the other constituents, and while doing so solvent ven der Gieasgusammensetzung duröh Veffdaapffn removed θο DA® a feate, photographiaehe Aufzeiohnungssehieht'auf iinein eißöiiö th carrier remains * As carriers, the photograph in the usual materials used word enι

O
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The recording materials according to the invention are suitable Copy images of different colors according to the type of used To produce dye precursors.

According to a particular embodiment, the 'exposure of the image-wise covered recording layer with toner carried out in such a way that that initially creates a latent image from traces of dye is, the latent image then through a so-called optical Development is converted into a visible image.

The optical development takes place preferably after the design removal of the toner image by uniform exposure of the recording layer, which contains the latent or barely visible image, with visible radiation occurring in the spectral Absorption band - the product lies through the image-wise Exposure of the photosensitive composition mentioned above became. -It is advantageous to use a blocking filter in the optical development exposure that absorbs all the light absorbed, which corresponds to the wavelength which is inherently by the components of the not previously exposed recording layer is absorbed. .

The image-enhancing effect is noticeably accelerated and the Image density increases when heat is applied during * optical development.

According to another embodiment, the initially formed. latent dye image is developed or enhanced into a visible image by making the recording layer uniform heated, so that one can speak of a thermal development.

Suitable light sources for use in exposing the Recording materials according to the present invention are sources of UV radiation, xenon gas lamps, incandescent lamps and flash lamps. Sunlight is also suitable for this exposure. For even exposure for optical development an infrared lamp is preferably used, which also emits in the visible spectrum. '

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The dye copies obtained can be stabilized by treating the radicals of the free radical forming compounds with a washes out suitable solvents or a mixture of solvents, e.g. with a liquid hydrocarbon such as petroleum ether, if necessary mixed with acetone, or - if the compound in question is sufficiently volatile - by simply adding it evaporated by increasing the temperature. For the latter 'purpose and because of the high photosensitivity, carbon tetrabromide is used or a mixture of carbon dioxide tetrabromide and Iodoform preferred.

During the exposure, the photoconductive material stands with a conductive body in contact through which the charges can be discharged. According to a preferred embodiment, the photoconductive recording material is therefore on attached to a conductive carrier or on a carrier that was provided with an electrically conductive intermediate layer.

Suitable supports are, for example, electroconductive plates or sheets with 'an electrical resistance which is at least one hundred times lower than that of the recording layer'. Preference is given to supports whose surface resistance does not exceed ΛΟ '£ 1 per square.

Useful conductive plates are, for example, plates made of metals such as Aluminum, zinc, copper, tin, iron or lead.

Overly insulating substrates can be coated with a conductive, adhesive layer or intermediate layer.

Suitable electroconductive intermediate layers for insulating substrates and e.g. vapor-deposited layers made of metals and conductive Metal compounds (metal oxides or metal salts), such as conductive silver, tin, aluminum, titanium dioxide and copper iodide layers, transparent conductive polymer layers, e.g. applied from polymers containing quaternized nitrogen atoms such as those described in British Patent 950,960 or layers described in US Pat

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contain conductive particles dispersed in a binder, e.g. Soot and metal particles. The binder used for these particles has a specific resistance, which is preferably is lower than 10 Ohm.cm. A useful binder for this purpose is gelatin.

Transparent recording materials are produced by the dye-forming compounds together with an or several transparent photoconductors and (if necessary) a suitable one Binder from a solution on a conductive, transparent carrier or on a transparent, insulating Attaches carrier, which was covered with an electroconductive, transparent intermediate layer.

As a translucent carrier? are plastic films that have an optical Density i ^ cht over 0.10, preferred, for example. a slide off Polyethylene terephthalate or cellulose triacetate. The conductive intermediate layer preferably consists of a metal coating. e.g. an aluminum layer applied in a vacuum, which has an optical density of -not more than 0.30 or a conductive, transparent polymer layer composed, for example, of an organic polyionic polymer, e.g. a polymer containing quaternized nitrogen atoms, such as quaternized Contains polyethyleneimine or sulfonated polystyrene.

In the case of reproduction techniques in which the prints are to be produced on an opaque or semi-opaque base, preference is given to Paper used as a support for the recording layer.

Paper that has insufficient electrical conductivity is coated or soaked with substances that reduce the conductivity increase, e.g. laminated with a conductive metal foil.

Conductivity-increasing substances used in the paper pulp are, for example, hygroscopic compounds and antistatic agents, such as described in US Pat British Patent 964,877, as well as antistatic agents of the polyionic type, e.g. CALGOF CONDUCTIVE POLYMER 261

AG 1130

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a registered trademark of Caigor. Corporation, Inc., Pittsburgh, Pa., USA for a solution containing 39.1% by weight effective conductive solids composed of a conductive polymer having repeating units of the following type: - ■ _s

aCT CH _{0 n} -,
dt γ ei- .01

HC 'CH-CH ₀

Paper is preferably impermeable to organic solvents made, e.g. by means of a water-soluble colloid or by strong hydration of the cellulose fibers as in Trap of glassine paper.

The present invention does not preclude the use of self-supporting photoconductive sheets. These sheets can be provided on the back with a "conductive _v " layer, which has been produced, for example, by vacuum evaporation with metals.

The development of the electrostatic charge image that is obtained on the photoconductive material takes place electrostatically Wearable material that adequately shields UV radiation and / or visible light.

In general, development is carried out by using the The plate or sheet that bears the electrostatic image is sprinkled with finely divided solid particles that form image-wise Electrostatically attracted or, repelled, so that one a powder image in accordance with the charged and uncharged, respectively Areas.

The term "powder" here denotes a finely divided, solid material which has an electrostatic charge image in it can convert a visible image. The main claim to form a powder image is that the powder can form a layer which the covered area

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can shield against electromagnetic radiation, by which the dye formation of the color-forming, photosensitive mixture could begin. ■ ■

Known methods of dry development of the electrostatic latent image include cascade, powder cloud, magnetic brush and hair brush development "These are based all on the application of a dry toner to the surface carrying the electrostatic image _t where Coulomb forces attract the toner or repel so that it sticks in the electrostatically charged or uncharged areas. The toner itself preferably has a charge obtained trioboelectrically.

The developing powders preferably absorb visuals Light and UV radiation are strong and are preferably non-sticky so that they can be easily removed by rubbing or by means of a stream of air can be removed.

Suitable development powders with these properties are described, for example, in British patent specification 947 479 and in TJS patent. 3 246 148.

However, the present invention is not limited to the use of a dry toner. Indeed, it is also possible to apply a liquid development process (electrophoretic development), whereby particles are dispersed through Electrophoresis can be deposited from a liquid medium. In this case, the recording material which is the electrostatic Charge model carries, preferably smooth (non-porous) and possesses only a weak adhesion for the electrophoretically settled toner particles, so that these particles are easily rubbed off after the developing liquid is evaporated can. Organic photoconductive recording layers are particularly suitable for this purpose, ι

The toner in this case can be any powder which forms a suspension in an insulating liquid. the Particles get a negative or positive in contact with the liquid

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Charge, what is to be approached the zeta potential, the opposite of the liquid phase is built up. The sign and the size of this particle charge is a puncture of the dielectric constant of particles and liquid. The excellent properties of these liquid developers are the most uniform Polarity of the dispersed particles and their great resolving power when using colloidal suspensions will.

Suitable electrophoretic developers are described, for example, in U.S. Patent 2,907,674 and in British Patent Specification 141 described.

In those cases where a transferable toner is used the powder deposit that forms the developed image can be removed from the carrier that contains the electrostatic charge, be transferred to a carrier that supports the photosensitive, * color picture, "ade mixture contains; in the latter case each" J known methods of transferring imagewise powder from one carrier to another have been used; such powder transfer processes are known in electrophotography. If an electrostatically attractable powder is used, then the powder image is transmitted by electrostatic attraction, e.g. according to the method of British patent specification 658 699

When a powder with ferromagnetic properties to develop of the electrostatic latent image is used, the powder can be transferred by magnetic attraction.

If a temporary powder image has been formed on the support on which the final dye image is to appear, so the wearer, which is shielded imagewise from active electromagnetic radiation, is exposed to the radiation and turned on creates the dye image in the unshielded areas of the support.

The following examples illustrate the present invention. Unless otherwise stated, the percentages are percentages by weight. , "·

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example 1

On a polyethylene terephthalate carrier of 100 y. a conductive transparent layer of an aqueous gelatin solution and CALGOU CONDUCTIVE POLYKER 261 (trade name) is applied in a weight ratio of 2: 1. The coating is carried out in such a way that the dried layer contains 2 g gelatin per m 2. The specific electrical resistance of the layer is 1 χ 10 0hm.cm at a relative humidity of 50 %. -

An electrophotographic recording material is produced by applying to this conductive layer a solution that contains. :

Trichlorethylene 50 ml

1,2-dichloroethane 45 ml

Carbon tetrabromide x 1.2g

1.2 g
1.2 g

Triphenylstibine 0.22 g

Poly-N-vinylcarbazole 5 g

Iodoform>

Spiropropane compound 1 from Table 1

-el

OCH

C = CH-CH = C

- CH β

0.0400 g 0.0105 g

Cl "

1-COOC ₂ H ₅

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Cl "

0.0035 S

.The dried recording layer, which is approximately 4-, 5 "g of poly-N-

2
Vinyl carbazole per m contains,., Is charged with a negative corona charge and at 100 lux / sec. Contact exposed through a microfilm slide using incandescent lamps.

The latent image is developed with an electrophoretic developer which is prepared by the hereinafter-mentioned concentrated Entwieklerzusammensetzung in a volume ratio of 15/1000 (with ISOPAR H trade name for a isoparaffiniseh.es hydrocarbon mixture having a boiling range of 177-188 ⁰ C of Esso Belgium NV Antwerp, Belgium) diluted:

Soot with an average particle size

of 20 μ 30 g

Zinc monotridecyl phosphate as a dispersing agent 1.5 g ISOPAR H (trade name) 750 ml

Resin solution prepared as described below 150 g

The resin binder solution is prepared by heating 500 g of ALKYDAL L 67 (trade name of Farbenfabriken Bayer AG, Leverkusen, for an alkyd resin modified with linseed oil (67 wt 6O ⁰ C, until a clear solution is obtained, and subsequent cooling.

A high-contrast, positive toner image of the image contained in the microfilm is obtained.

The recording layer, which is imagewise covered with toner, becomes 2 Minutes with a HPL 80 watt high pressure silver vapor lamp by Philips * Gloeilampenfabrieken N.V., Eindhoven, Netherlands. The exposure distance is 15 cm. In the fields of, that are not shielded by the toner will appear a deep blue color.

The toner image is rubbed off.

The exposed recording layer is stabilized by heat treatment at 17O ⁰ C within one minute against background staining ..

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After removing the toner, a sharp, stable, negative, deep blue copy of the 'is obtained on the transparent carrier Image contained in the microfilm original.

Example 2

It is produced a e1ektrophotographisehes recording material by a conductive layer as wi described in Example 1 d _s applying a composition containing?.

Trichlorethylene 10 ml

Methylene chloride. 40 ml

Carbon tetrabromide 1.2 g

Iodoform 1.2g

Spiropyran compound 1 of Table 1- 1.2 g Polystyrene 2.5 g

1,2-dichloroethane "35 ml

.Cl "

0.0020-g

H ₅ C

CH-

-CH,

2 g

The dried recording layer containing approximately 2 g of photoconductor per m contains a negative corona charge charged and with 1000 lux / sec. with the same light source and template as described in Example 1, contact-exposed. The latent image is developed electrophoretically with the developer of Example 1 for 5 seconds and as described there further processed.

A deep blue image is obtained as in Example 1, which shows the area that are not covered with the toner.

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Example 3

On a polyethylene terephthalate carrier of 63 .mu.m is a conductive, transparent layer applied, consisting of:

10% aqueous solution of CALGON CONDUCTIVE POLYMER

Methanol

ml
ml

The application is carried out in such a way that the dried material contains 1.75 g CALGON CONDUCTIVE POLYMER 261 per _m ² . Of the

electrical resistance is humidity of 50 %

-0- / cm with a relative

An electrophotographic recording material is produced by applying a solution of the following composition to the conductive layer applies:

1,1,2-trichloroethane 50 ml '-

Methylene chloride., "" 45 ml

Carbon tetrabromide 1.2 g

Iodoform spiropyran compound 1 from table triphenylstibine '2-mercaptobenzothiazole Poly-N-vinyl carbazole

Cl "

1.2 g 1.65 g 0.425 g 0.125 g 5 g

0.0064 g

HSO ₄ "0.0200g

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Cl "

0.0770 g

The application is carried out so that 4.5 g of photoconductor

2
per m are present.

After a negative corona charge, the recording layer becomes episcopic with a multi-colored line original in one Microfilm camera exposed for 2 seconds at 5500 lux. The aperture is 4 · .5; the original is optically reduced by 20 times. That The electrostatic charge image obtained is developed as in Example 1.

The recording layer is while it is imagewise with toner is covered, 3 minutes with an 80 watt high pressure mercury vapor lamp, Type HPL, from N.V. Philips'Gloeilampenfabrieken, Eindhoven, Netherlands, exposed, which is set up at a distance of 10 cm. Then the latent image obtained becomes optically developed into a deep blue dye image with a maximum density of 1.5 by means of a uniform exposure of 10 seconds duration with a 250 watt infrared lamp, which also emits in the visible spectrum (the lamp is traded by Bic and Berntsen, Copenhagen, Denmark).

A blocking filter is used during the uniform exposure (Corning CS, 3-67), which absorbs all light with a wavelength of less than 54-0 nm.

A dye image is obtained by optical development, that corresponds to the areas that are not shielded with toner.

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Claims (1)

23ZZT04- Claims ■ 1. A method for generating a dye image in a photo ■ conductive recording layer or a photoconductive recording sheet, with a conductive backing layer through the following process steps: (1) Formation of an electrostatic latent image on the layer or sheet containing: (A) A photoconductive compound forming the recording layer or sheet for electrophotography Makes recording suitable, (B) at least one dye precursor or a mixture of dye precursors, which one or form multiple dyes when in active relationship with a photo-exposed polyhalogen compound bond, 'which generates photo radicals (C) a photosensitive polyhalogen compound which Photo radicals generated by exposure to active electromagnetic radiation, (2) Formation of a temporary powder image by brings electrostatically attractable, solid particles to the recording layer or the recording sheet, which contain the electrostatic 'latent image, (3) uniform exposure of those bearing the powder image Surface with active electromagnetic radiation, which is capable of in the recording layer or the Recording sheet to produce a visible dye image or a latent image that is optically a dye image can be developed which coincides with the areas not covered with the particles, and Removal of the powder image after the visible dye image or the latent image has been created. AG 1130 309847/1052 2. The method according to claim 1, characterized in that the recording layer or sheet is transparent and contains an organic photoconductor. 3. The method according to claim 2, characterized in that the photoconductive compound is poly-N-vinylcarbazole. 4 ·. Process according to claim Λ , characterized in that the dye precursor is a spiropyran compound. · 5 · The method according to claim 4, characterized in that the The spiropyran compound contains at least one pyran ring which is in the ortho- and meta-position to the oxygen atom condensed benzo or naphthoring system or another substituted or unsubstituted, higher, aromatic, polycyclic ^ s, condensed ring system. 6. The method according to claim 4, characterized in that the Spiropyran compound a Spirobehzpyran, a Spirodinaphthopyran, a Spirobenznaphthopyran, a 1,3,3-Trimethylindolinbenzpyran, a 1,353-trimethylindoline naphthospiropyran or represents those spiropyrans which contain fused, aromatic rings of the anthracene or phenanthrene type. 7. The method according to claim 1, characterized in that the dye precursor is a compound which corresponds to one of the following general formulas: (D O OH k-σ AG 1130
O 309847/1052 in which "mean: E * an aliphatic ^ group including a substituted one aliphatic group, an aryl group including a substituted aryl group or together with E 'the necessary Atoms to close a homocyclic entry, R 'hydrogen, a lower alkyl group including a' substituted lower alkyl group, including a phenyl group a substituted phenyl group or a. Phenoxy group, Z ^ the atoms necessary to make a hoiäo cyclic input or a .homocyclic single system, including one such a ring or ring system in substituted form, Zo the atoms necessary to make a homocyclic inclusion to close a substituted, homocyclic ring, Rp is a lower alkyl group and η the numbers T or 2. 8. The method according to claim 1, characterized in that c the visible coloration is obtained by looking at (B) at least an indolizine derivative is used which corresponds to the following general formula (I): in which: Z the atoms necessary to make a fused 6-membered to include heterocyclic nitrogen-containing inputs that have two double bonds, or such a Bing, which represents part of an adjacent, polynuclear single system, including such a single or single system in substituted egg, E ^ hydrogen or nitro, or E ^ and E ₂ together are the atoms necessary to close a fused bomocyolic ring, Eg and E, (identical or different) each hydrogen, one Alkyl group including a cycloalkyl group or substituted alkyl group, an alkenyl group, a . Acyl group, a nitro group or an aryl group -ein- AG 1130 309847/1052 finally a substituted aryl group, where at least one of the substituents E ^ or R, is hydrogen, and at least one aldehyde or aldehyde derivative of one of the following Species : · Ci) aldehyde, which has a primary, secondary or tertiary amino group which is bound to the aldehyde group through a conjugated system, ' Cii) Hydroxyaldehyde in which the hydroxyl group and aldehyde group are linked by a conjugated system, and derivatives of this hydroxyaldehyde in which the hydrogen atom of the hydroxyl group ^{1 has been} replaced by a metal atom or an alkyl group, and those derivatives in which the aldehyde group has been masked as an acetal group. 9 · The method according to claim 1, characterized in that the photosensitive polyhalogen compound corresponds to the following general formula: '* . · V b ' ⁿ y in which: A, B, X and Y each represent a halogen atom from the group consisting of chlorine and bromine or iodine, or one of the substituents A, B, X or Y is an alkyl group including a substituted alkyl group, a quinoxaline group, an aryl group, a - substituted one Aryl group or an aroyl group and the other substituents chlorine, bromine or iodine, or at least two of the substituents A, B, X or Y is an aromatic acyl group and the other substituents are chlorine, bromine or iodine. 10. The method. According to claim 9j, characterized in that the polyhalogen compound is carbon tetrabromide. 11.Verfahren according to claim 1, characterized in that the Recording material after carrying out steps (1) to (4) is treated with a solvent in order to to remove residual polyhalogen compound by extraction. AG 1130 309847/1052 12. The method according to claim 1, characterized in that the recording material after performing the steps (1) to (4) is heated to remove the residual polyhalogen compound by evaporation. 13. The method according to claim 1, characterized in that the electrostatic, latent image is produced by the recording layer or the recording sheet is evenly charged electrostatically and imagewise with a conductivity-increasing charge Radiation exposed. 14. The method according to claim 1, characterized in that the powder image is produced by dry powder development will. 15. The method according to claim 1, characterized in that the powder image is formed by electrophoretic development. _ _:. 16. Photosensitive recording material, characterized in that that it is in a recording layer or a recording sheet formed by exposure to electromagnetic Radiation producing a visible coloration contains: (A) 10 to 70 wt .- ^ of a photoconductive compound which makes the recording layer or sheet suitable for electrophotographic recording, (B) 2 to 20% by weight of at least one dye precursor or a mixture of dye precursors which form one or more dyes when they are in are actively related to a photo-exposed polyhalogen compound that generates photo radicals, (C) 5 to 40% by weight of a photosensitive polyhalogen compound, the photoradicals generated by exposure to active electromagnetic radiation. AG T130 309847/1052 17 · A photosensitive recording material according to claim 16, characterized in that the recording layer or the recording sheet is transparent and comprises an organic photoconductor. -. 18. A photoconductive recording material according to claim 17 _} ■ characterized in that the photoconductive compound is poly-IT-vinylcarbazole. 19 photosensitive recording material according to claim 16, characterized in that the dye precursor is a spiropyran compound. 20. Photosensitive recording material according to claim 19 _}, characterized in that the spiropyran compound contains at least one pyran ring which, in the ortho- and meta-position to the oxygen atom, is a condensed benzo- or ITaphthoring system or another, substituted .. or unsubstituted, higher, aromatic, poly- ^{x has} cyclic, condensed ring system. 21. Photosensitive recording material according to claim 19, characterized in that the spiropyran is a Spiodibenzpyran, a spirodinaphthopyran, a spirobenznaphthopyran, a 1,35 3-trimethylindoline benzpyran, a 1,3,3-trimethylindoline naphthopyran or is those spiropyrans which are condensed, aromatic rings of the anthracene or phenanthrene type contain. 22 .. Photosensitive recording material according to claim 16, characterized in that the dye precursor is a compound which is one of the following general Formulas corresponds to s AG 1130 309847/1052 OH in which mean: R ^ an aliphatic group including a substituted *, aliphatic group, an aryl group including a substituted aryl group, or together with R ^ / the atoms necessary to produce a homocyclic hing close,- E ^{1 is} hydrogen, a lower alkyl group including a substituted lower alkyl group, a phenyl group including a substituted phenyl group or a phenoxy group, Z ^ i the atoms necessary to make a homocyclic ring or to close a homocyclic ring system, including such a ring or ring system in substituted form, % 2 necessary ^d i ^e atoms, a-homocyclic ring, including a substituted to close homocyclic ring, - Rp is a lower alkyl group and η the numbers 1 or 2. 25 photosensitive recording material according to claim 16, characterized in that the visible color is obtained by adding at least one indolizine derivative under (B) is used, which corresponds to the following general formula (III):. '"■" VJi-ί | -3 AG 1130 ■ 309847/1052 in the "mean: Z the atoms necessary to form a fused 5-membered, to close nitrogen-containing input that has two double bonds, or such a ring that has part, of an adjacent polynuclear ring system, including such a ring or ring system in substituted form, R _-1 hydrogen or nitro, or R ^ and Rg together the necessary atoms to close a fused, homocyclic ring, Rg and Ή .- * (identical or different) per hydrogen, an alkyl group including a cycloalkyl group or substituted alkyl group, an alkenyl group, an acyl group, a nitro group or an aryl group including a substituted aryl group, where at least one of the substituents | t | or R, is hydrogen, and .-_ at least one aldehyde or aldehyde derivative of one of the following Species : (i) Aldehyde, which has a primary, secondary or tertiary amine group which is bound to the aldehyde group through a conjugated system, and (ii) Hydroxyaldehyde, in which the hydroxyl group and the Alde-Xjd group linked by a conjugated system and derivatives of this hydroxyaldehyde, in which the Hydrogen atom of the hydroxyl group has been replaced with a metal atom or an alkyl group, and such Derivatives in which the aldehyde group has been masked as an acetal group. 24-. Photosensitive recording material according to claim 16, characterized in that the photo-sensitive polyhalogen compound corresponds to the following general formula: A X AG 1130: 309847/1052 in the "mean: ■ * A, · B, X and Y j ^e a halogen atom of the group chlorine, bromine or iodine, or one of the substituents A, B, X oder.Y an alkyl group including a substituted alkyl group, a quinoxaline group, an aryl group, a substituted one Aryl group or an aroyl group and the other substituents chlorine, bromine or iodine, or at least two of the substituents A, B, X or Y an aromatic acyl group and the other substituents chlorine, bromine or iodine. 25 · Photosensitive recording material according to claim 24, characterized in that the polyhalogen compound is carbon tetrabromide. 26. Phptosensitiv.es recording material according to claim 16, characterized in that the recording layer is attached to a conductive support or to a support which is covered with an electrically conductive intermediate layer is. AG 1130 309847/1052