DE2415459A1 - IMAGE GENERATION PROCESS - Google Patents

Description

The invention relates to an imaging method; it relates in particular to the generation of images through migration and a method of stabilizing the latent electric images thus formed.

Recently, a migration imaging system (imaging system) developed that is capable of producing high quality images with a high density, a continuous Tint and a high resolution. Such migration imaging systems are, for example in the American patent applications Hr.- 837 780 and 837 591 described. In a typical embodiment This new migration imaging system is implemented in an imaging device comprising a substrate with a migration layer which consists of a layer of a softenable material and an electrically-photosensitive migration material exists, an image is generated in the following manner: an

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Generates a latent electrical image by "for example electrically charging the device" and placing it in a pattern activating electromagnetic radiation such as light. When the photosensitive migration material is present in the form of a layer, but is in a certain degree Distance from a surface of the layer from the soft bear Material is located (layered structure), it migrates Migration material from the migration layer imagewise to the substrate when the imaging device is softened the softenable layer is developed.

One development method is "to have the imaging device exposed to a solvent which only dissolves the softenable layer. It leaves the photosensitive Migration material (usually in the form of particles) that under the action of radiation through the softenable When the layer is softened and dissolved, an image of migrated (changed) particles moves on the substrate, which corresponds to the radiation pattern or radiation diagram of an original, the material being the softenable Layer is essentially washed away. The particle image can then be fixed on the substrate. Preferred by many used photosensitive migration particles, the image generated by the above process is a negative of a positive originals, i.e. the particles are deposited in an imagewise configuration corresponding to those struck by the radiation Districts. Those parts of the photosensitive material that do not migrate to the substrate become together with the layer of softenable material washed away by the solvent. By varying the imaging parameters however, positive-positive systems can also be obtained. As in the above-mentioned American patent applications indicated, the layer of the softenable material can be at least partially obtained by using other development methods on the carrier substrate with or without a relatively non-

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migrated sample of the migration material belonging to the migrated material is complementary, remain behind. In another embodiment of the image generating device the migration layer contains a migration material that is within the layer of the softenable material in a Binder layer configuration is dispersed.

As used herein, the term "softenable material" means any practically insulating material which against the migration (migration) of the migration material through its interior (the body consisting of it) more permeable or can be made more permeable. Usually the change in permeability is achieved by having it through Contacting with heat, vapors, partial solvents and combinations thereof dissolves, partially dissolves, melts and softened.

As used herein, the term "electrical latent image" and its various modifications are images to understand, which have been generated by the charging exposure method using conventional electrometric Methods are not easily detectable, such as an electrostatic image of such a type as, for example occurs in xerography, so that after exposure (when using preferred exposure amounts) a hardly detectable or at best there is very little change in electrostatic or Coulomb force, as well as latent electrostatic Images of a type similar to that found in xerography, usually produced by means of a Standard electrometers are easily measurable, i.e. these latent electrostatic images have a surface potential value on, which is usually at least about 5 to 10 volts.

As used herein, the term "frangible layer" or "frangible material" means any layer or layer to understand any material that is used in the Lace 5 ^ t,

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break up during development so that parts of this Layer can migrate to the substrate in an imagewise configuration. The breakable layer can be at different Embodiments of the migration imaging devices can be particulate or semi-continuous.

Under the term "adjacent" as used herein, as defined in "Webster's New Collegiate Dictionary", is second Edition, 1960, to understand "in actual contact", "touching", "close to but not in contact", "adjacent".

In certain processes for forming the latent image, non-photosensitive images can be used to produce the images or inert, frangible layers and a particulate Material can be used when, for example, a latent electrostatic image is generated by a variety of methods is, for example by imagewise charging using a mask or stencil, by generating a such charge image on a separate photoconductive insulating layer according to the usual xerographic reproduction ■ method and subsequent transfer of this charge image onto the imaging device by placing the two Bringing layers in very close proximity to one another, and using strikethrough techniques such as those for example in U.S. Patents 2,982,647, 2,825,814 and

2,937,943. In addition, charge images according to the selected, shaped electrodes or electrode combinations by discharge processes as described in U.S. Patents 3,023,731 and 2,919,967, or by methods such as those described in US patents

3 001 848 and 3 001 849 are described, as well as by electron beam recording methods, as described, for example, in US Pat. No. 3,113,179 will.

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The characteristics of the images generated depend on the various process stages, "for example charging, exposure and development as well as the respective combinations of the process steps · A high density, a continuous one Tint and high resolution are some of the possible characteristics of an image · The image in general becomes characterized as a fixed or unfixed particulate Image with or without any part of the softenable layer and non-migrated parts of the layer on top of the Image provided facility remain behind.

Investigations on this new migration imaging system have now led to the fact that it is now possible according to the invention to remove the latent electrical images produced by migration to stabilize, so that the migration imaging device provided with the latent electrical image in its State with the latent image stored over long periods of time, for example days, months and even years or can be stored before it is developed to achieve migration into the interior of the softenable splint, Surprisingly, in many cases the stabilization also enables development in the surrounding room light (ordinary daylight) shining on the migration imaging device usually has an activating effect.

The aim of the present invention is therefore to provide a new system for stabilizing latent electrical generated by migration To indicate pictures. Another object of the invention is to provide a new migration imaging method that uses the Development and handling of films provided with a latent electrical migration image in the surrounding actinic Radiation, for example in Baumlieht, made possible shortly after exposure. Another aim of the invention is e3, a migration image display method indicate what the optical control of the film development in visible

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Light allows shortly after the formation of the latent image, so that the film development for the respective latent image on the PiIm can be optimized.

The above objects and other advantages are achieved in accordance with the present invention achieved by manufacturing a migration imaging device with a migration layer with a softenable material and a migration material, by creation a latent electrical image in the migration layer and then stabilizing the latent electrical image Image either through a weak pre-development enhancement that is insufficient to allow an image-wise migration of the migration material into the interior of the softenable layer, or by keeping the imaging device in the dark. By stabilizing the latent electric image, it is possible to use the image forming device to handle the surrounding activating radiation without destroying the latent image, and it it is possible to do this for days, months and even years between the generation of the latent electrical image and of development to achieve selective internal migration · For many light-sensitive migration materials The apparent sensitivity of the imaging device can be reduced by the pre-development softening can be increased to about twice that of normal image formation without the pre-development softening step.

The invention is an image generation process that is characterized by the following levels:

(a) Manufacture of an image forming device having a migration layer made of a migration material and a softenable material whose resistance to the migration of the migration material can be reduced sufficiently, ura

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to enable migration of the migration material into the interior of the softenable material,

(b) forming a latent electrical image in said imaging device and

(c) stabilizing the latent electrical image.

The invention also relates to a migration layer which is characterized in that it consists of a migration material and a softenable material, the The resistance of the last-named material to the migration of the migration material can be reduced sufficiently, um.a migration of the migration material into the interior of the softenable material, and a stabilized has a latent electrical image.

The invention thus relates to a migration layer which contains a migration material and a softenable material comprises a stabilized electric latent image and a method of stabilizing the electric latent image Image in which an image forming device having the above-described migration layer is produced, in creates a latent electrical image of the migration layer and the latent electrical image either by storing the migration layer in the dark or by applying heat, Vapors or partial solvents is stabilized in a predevelopment softening stage. After stabilizing the latent electrical image can be the migration layer of a activating electromagnetic radiation can be exposed without the latent image being lost, and it can reach up to over Years between the creation of the latent electrical image and the development that led to selective migration allowed to be stored inside the softenable layer.

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Further objects, features and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawings Drawings mean:

Fig. 1 q is a partially schematic representation of an image generating device with a layered migration layer, which is suitable for the inclusion of on it latent electrical images generated and stabilized according to the invention are suitable;

Pig · 2 is a graph of the two curves for electric-photosensitive Selenium, in which the blue light contrast density of one under surrounding activating Radiation developed film or one before development and after stabilization of the latent electrical Image exposed in this way to film against storage time in the dark at room temperature negative charging and exposure and prior to exposure to ambient light and heat generation as well the electric field (volts / micron) versus time in minutes after charging and immediate exposure, but before heat development for an imaging device with a layered migration layer, as described in Example 1 below but in which the softenable layer is about 1.6 microns thick. The contrast density is defined as the background density minus the image area density.

1 shows an image-generating device 10 which consists of a migration layer 14 and a substrate 11. The migration layer 14 consists of the migration material 13 and a layer 12 made of a verifiable material. The substrate 11 is preferably made of an electrically conductive material, but it can also be made of an insulating I "~ -

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material or a combination of both materials, for example a thin electrically conductive layer on one insulating layer. The substrate can be mechanically rigid or flexible, transparent or opaque (opaque) depending on the needs of the particular imaging system. The migration layer 14 comprises the migration material 15 in the layer 12 of the softenable material, the migration material 13 can be continuous or particulate, but if continuous it should be "breakable" be. By "frangible" is to be understood here that the migration material before or during the imaging process Particles can be broken. As used herein, "softenable material" means any practically insulating To understand material that can be made more permeable to migration through its interior.

The softenable material layer 12 can be made from any of the suitable softenable materials defined above. Examples of suitable typical softenable materials are polystyrenes, alkyd-substituted polystyrenes, polyolefins, Styrene / acrylate copolymers, styrene / olefin copolymers, Silicone resins, phenolic resins and amorphous organic glasses, typical suitable materials are Staybelite Ester 10, a partially hydrogenated rosin ester, foral ester, a hydrogenated eosin triester, and Neolyne 23, an alkyd resin (all products from Hercules Powder Co.), SR 82 and SR-84 silicone resins (both products from General Electric Corporation), Eastman Chemical, Velsicol X-37, a polystyrene / olefin copolymer from Velsicol Chemical Corp. , Hydrogenated Piccopale 100, a highly branched polyolefin, HP-100 ^

Piccotex 100, a methyl styrene / vinyl

toluene copolymer, Piccolastic A-75, 100 and 125, all Polystyrenes, Piccodiene 2215, a polystyrene / olefin copolymer (all products of Pennsylvania Industrial Chemical Co.), Araldite 6060 and 6O7I, epoxy resins from Firna Ciba, Amoco 18, a poly-a-methylstyrene from Aaoco CUi-a.

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Corp., Amberol S3 ?, phenol-formaldehyde resin, ethyl cellulose, and Dow C4, a methylphenyl silicone, all Dow Chemical products, M-140, an ordinary synthesized styrene / n-butyl methacrylate copolymer, E5O6O1A, 'a phenylmethyl silicone resin from Dow Corning, Epon 1001, a bisphenol A epichlorohydrin epoxy resin made by the Company Shell Chemical Corp. as well as PS-2 and PS-3 "both polystyrenes and ET-693t, a phenol-formaldehyde resin from Dow Chemical as well as an ordinary synthesized styrene / hexyl methacrylate (80/20 mol%) copolymer and Nirez 1085, a polyterpene resin from Tenneco Corp.

Although 3 no practical thickness for the layer 12 from the softenable material can be used is a more satisfactory one Layer 12 thickness ranges from about 0.5 to about 16 microns. A range from about 1 to about 4-micron is preferred because such a peck is qualitative provides high quality images and at the same time a light one Construction of the image generating device allowed. The migration material can be any suitable material. At different Embodiments of the invention can be the migration material photoconductive, photosensitive, photosensitive inert, electrically conductive, electrically insulating, magnetic, colored, transparent or it may have any other property ^ e after that for this particular embodiment intended use

Under the term "photosensitive" as used herein is in particular to understand "electrically-photosensitive". Although It has been found that photoconductive materials (the term "photoconductive" as used herein is in its to be understood in the broadest sense and includes materials that exhibit increased electrical conductivity when used with electromagnetic radiation, and not necessarily exclude those that are found in xerography in a xerographic plate configuration) represent a class of materials known as "eloct-ric

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light-sensitive "materials are united according to the invention, and although the photolextable effect according to the invention is often sufficient to achieve an" electrically-light-sensitive "material, this is not a necessary effect. A necessary _.: effect is obviously the selective transfer of the charge into the migration material, within it or out of the same, this shifting (shifting) being caused by the action of light on the mass or the surface of the electrically-photosensitive material when the material is exposed to activating radiation, including in particular the photoconductivity effects, photoinjection, photoemission, photochemical effects and other effects that lead to a selective relocation (shifting) of the cargo.

For reasons of convenience and versatility, an electrically-photosensitive migration material is in particular in cameras in which the lighting effect can easily be used, in conjunction with the one according to the invention latent electrical image stabilization is a particularly preferred migration material.

The migration material 15 can be any suitable inorganic or organic photosensitive material. Examples of typical suitable inorganic materials are Vitreous selenium, vitreous selenium alloyed with arsenic, tellurium, antimony or bismuth and the like, cadmium sulfide, zinc oxide, cadmium sulfoselenide and many others. In U.S. Patents 5,121,006 and 3,288,603, quite a few are typical inorganic pigments and suitable binders for it. Examples of typical suitable organic materials are Watchung Red B, a barium salt of the 1- (V-methyl-5 ' -chloro-azo-benzene-2'-sulfonic acid) -2-hydrochydroxy-3-naphtho acid (CI. No. 15865 from DuPont), Indofast Double Scarlet Toner, a pyranthrone-type pigment from Harmon Colors, Ojiindo Magenta RV-6803, a quinacridone, e.g.

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Monastral Bed B (EI DuPont), Cyan Blue GTNJ ?, the beta form of copper phthalocyanine (OI Hr. 74-160 from Collway Colors), Monolite Fast Blue GS, the α form of metal-free phthalocyanine (CI. No. 74100 from Arnold Hoffman Co.), Diane Blue, ^ -Methoxy- ^ V-diphenyl-bis-Ci "-azo-2" -hydroxy-3 "-naphthanilide) (CI. No. 21180 from Harmon Colors) and Algol GC, polyvinylcarbazole-1,2,5,6-di- (P, D ¹ -diphenyl) thiazole-anthraquinone (CI. No. 67 JOO from General Dyestuffs). The above list are just a few typical examples of those according to the invention usable organic and inorganic photosensitive materials and this list is by no means exhaustive.

The thickness of the migration embodiments constructed in the form of frangible layers is preferably within Range between about 0.01 and about 2 microns, although also frangible layers about 5 microns thick give good results on some materials. When the breakable The migration layer consists of discrete particles

preferred average particle size within the range no more than about 2 microns. Images with an optimal density are created by particles with an average Size no more than about 0.7 microns.

The binder migration layer embodiments described in U.S. Patent Application No. 857,591 referenced above and the layer embodiments preferably contain migration material particles an average size of no more than about 2 microns. An optimal range for the binder and layer configuration particles of the migration material is an average size of no more than «About 0.7 microns.

The embodiment of the image suction device shown in FIG is in the form of the layer configuration, i.e. the migration material 13 is in the form of layers in

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r 13 -

The layer configuration defined above means that the migration material 13 is in the form of a layer in the layer 12 of the softenable material, but that it is spaced from a surface of the layer 12 of the softenable material. The migration layer 14 can also be present in the binder configuration in positive-negative migration layers (i.e. according to the definition above, the migration material 13 is dispersed within the layer 12 of the softenable material), i.e. if the migration takes place in the exposed areas in contrast to the more typical binder effect in which the migration of the particles takes place in the non-exposed areas. In the binder configuration, the concentration of the migration material 15 within the layer 12 of the softenable material is preferably sufficiently low to prevent the migration layer from either becoming electrically conductive or being able to transport charges. For example, the positive-negative migration binder layer composed of selenium particles preferably has a concentration of 4.5 (10) particles. an average diameter from about 0.5 per P- cnr, when it has been subjected to the inventive method, a latent electrical image stabilization.

The substrate 11 can be electrically conductive on an insulator. Electrically conductive substrates generally facilitate this Charging of the image forming device and typical examples are metals such as copper, chromium, stainless steel, Brass, zinc, or it can consist of electrically conductive plastics and rubbers · The electrically conductive substrate can in the form of a layer on an insulator such as plastic, glass or paper, such as a practical transparent, tin oxide-coated glass sold under the trade name Nesa by the company Pittsburgh Plate Glass Company is available.

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_ 14 -

The latent electrical image can be generated by a wide variety of methods, for example by charging by means of a template, by electrostatic transfer of the charge, by charge induction and charging processes. An example of the last-mentioned method is a method in which the free surface of the layer 12 can be electrostatically charged from the softenable material, for example by means of a corona discharge device, as generally disclosed in U.S. Patents 2,836,725 and. 2 777 957 and exposed to electromagnetic radiation to which the photosensitive migration material 13 is sensitive, i.e. the electromagnetic radiation is with respect to the photosensitive migration material 13 actinic or activating. Typical examples of suitable actinic electromagnetic radiation are radiation from ordinary light bulbs, X-rays, radiation from charged particles, infrared radiation, ultraviolet radiation and combinations thereof. Other charging methods ranging from rubbing the charger to induction charging are described, for example, in US Pat. No. 2,934-649. If the substrate 11 is a Is insulating material or if there is no substrate 11, the charging of the image forming device for example, caused by contacting an electrically conductive surface with the imaging device brings. Alternatively, other methods such as those used in xerography for charging xerographic plates can be used with insulating backing layers are known. For example, the imaging device can use double-sided corona charging methods in which two corona charging devices on each side of the device are moved congruently relative to the device 10 with the opposite charge, are charged. Charge densities, which provide an electric field at the migration layer 14- of about 5 volts per micron to about 200 volts per micron, are satisfactory, ranging from about 40 to etv / a 100 volts per micron is preferred.

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The life of the latent electrical image can, if it is stabilized according to the method according to the invention, versus the lifetime of the latent electrical image for the respective migration on a layer in which the advantageous stabilization stage of the invention was not carried out, be extended. With the longer service life it can be a higher resistance to time, to a higher resistance to light and combinations thereof Act. The term "stabilized" (set) used here as well as the variants thereof, such as "stabilization" (setting when applied to the latent electrical image means obtaining a longer resistance to time or to Achieving longer resistance to light or combinations of that. Therefore, by the term "stabilized electric latent image" as used herein, it means an electric latent image To understand an image that is less affected by time or light or both than a latent electrical one Image that has not been stabilized.

For example, with regard to the extension of the resistance (service life) to time and light, it has been found that an image-forming device of the type shown in FIG of a softenable material, consisting of about 95 wt .-% of a styrene / hexyl methacrylate copolymer with a weight average. lent molecular weights of about 4-5,000 and about 5% by weight of a p-phenylformaldehyde resin, and which had a latent image formed by charging with positive polarity, no resistance to light and resistance to time of only 30 minutes would have. That is, the latent positive electrical image could not be exposed to light (actinic electromagnetic radiation) prior to the development of the image generation, and only a ZtAX-

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30 minutes if a loss of sensitivity and quality should be prevented. A period of 60 minutes between formation of the electric latent image and development resulted in a loss of speed and quality of 10%, while a period of 2 hours resulted in a loss of speed and quality of 40 % . It has now been found that if, according to the invention, the migration layer 14 is subjected to a pre-softening, for example by means of solvent vapors, which is insufficient for development (ie migration of the migration material into the interior), the durability or life of the latent positive electrical image can be extended to more than 1 day and the latent positive electrical image can be made insensitive to light (actinic electromagnetic radiation). That is, during this period of time, the latent positive electrical image is not destroyed by periodic exposure to actinic electromagnetic radiation, and if it is developed after this period, no change in sensitivity, resolution or quality is observed.

As a further example it should be pointed out that a similar Imaging device, as layer 12 of the softenable The material is the styrene / hexyl methacrylate copolymer contains and has a latent negative electrical image, a practically infinite life span (durability) if it is kept in the dark immediately after the electric latent image is formed. That that is, after a negative electrical latent image is formed, the negative electrical latent image faces the No change in terms of sensitivity, resolution and quality regardless of the period of time of development between the generation of the latent electrical image and the development, provided that the latent is negative electrical Image has been kept in the dark. However, if the latent

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negative electrical image at any time within about 200 minutes of its creation and before development When exposed to light (actinic electromagnetic radiation), the latent electrical image becomes at least impaired (degraded) and can be destroyed or extinguished. Will keep awake in the dark for about 200 minutes the latent negative electrical image, however, is resistant to light, i.e. it is periodic in relation to the subsequent one Less sensitive to exposure to actinic electromagnetic radiation. Such latent electrical images can after being stored in the dark for a period of at least 4 years and in some cases for longer periods without loss of sensitivity, resolution or quality Ambient light can be developed. When using milder Heat on the migration layer carrying the negative electrical image of, for example, 70 ° G for a period of about 10 seconds or from about 75 ° C for a period of about 1 Second becomes the resistance (life) of the latent negative electrical image to light in a corresponding manner extended. After applying mild heat in place of the Storage in the dark resulted in an interval of at least 4 x years between the generation of the latent negative electrical Image and the development to a less photosensitive latent electric image, which after 4 years without measurable Loss of sensitivity, resolution and quality developed could be.

Imaging occurs when the migration layer is subjected to development. During development, the resistance of the softenable material to migration of the migration material is sufficiently reduced so that the migration material can migrate into the interior of the softenable material. This can be achieved by exposing the migration layer to either heat, partial solubilization, solvent vapor, or a combination of lavons. As one * - tiellGS flikir.igos Lünun ^ anittel or Lo ..ur-emit!; <HLrr.pt ¹ liann to soften the Bxlderzeu ^ unsüeLnrichf up ·; -] odrs u ^ oi ^ neto

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8AD

Solvents can be used. Typical examples of suitable solvents are Freon TMC from DuPont, Trichlorethylene, chloroform, ethylxylene, dioxane, benzene, toluene, cyelohexane, 1,1,1-trichloroethane, pentane, n-heptane, Odorless Solvent 3440 (Sohio), Freon 113, from DuPont, m-xylene, carbon tetrachloride, thiophene, diphenyl ether, P-cumene, cis ~ 2,2-dichloroethylene, nitromethane, Ν, ΪΤ-dimethylformamide, Ethanol, ethyl acetate, methyl ethyl ketone, ethylene dichloride, Methylene dichloride, 1,1-dichloroethylene, trans-1,2-dichloroethylene and supernaphthalites (from Buffalo Solvents and Chemicals) and the various mixtures thereof.

It should be noted that the heat used in the development step, the solvent vapor used, that used partial solvent liquid and combinations thereof with advantage for practical implementation, stabilization of the electric latent image can be used according to the invention. The stabilization of the latent electrical image takes place using heat, a solvent vapor, a partial solvent liquid or combinations thereof for a period of time sufficient to in order to allow a stabilization, which however is not sufficient to the resistance of the softenable material against Reduce migration of the migration material 13. For example, if The application of heat at about 75 ° C for a period of about 1 second is sufficient to generate the latent electrical Stabilizing an image by the application of heat is generally the application of heat to a temperature of about 110 ° C for a period of about 20 seconds required, a sufficient reduction in the resistance of the softenable material to migration of the migration material 13 required to prevent the migration of migratory material 13 to allow inside the softenable material. Suitable development methods are such as, for example in US Patent 3,520,681 and in the American

See Patent No. 3,656,990.

Ztu? Achievement of long-lasting migration layers, i.e. for Making an imaging device with a longer shelf life can use the softenable material used be modified. In general, the softener can be Material for the production of a migration layer that lasts for a long time a latent electric after being made without changing the sensitivity, resolution and quality of the image Image can be generated, film-forming materials, such as those in American patent application No. 6,862 materials with polar groups, such as those described in U.S. Patent No. 3,729,310 and oxidizing materials such as those described in U.S. Patent Application No. 93 908 are described, are added. Examples of typical suitable additives, such as those in the above-mentioned American Patent applications are indicated, are p-tert-butylpheno! Formaldehyde- and p-phenylphenol-formaldehyde resins as included in respective trade names Bakelite 2 4-32 and Bakelite 5 254 from Union Carbide Corp. are available, halides, such as chlorocarbon compounds, esters, ethers, epoxy compounds, quaternary amines, alcoholic hydroxyl compounds, organic acids, such as acidic hydroxyl compounds, e.g. phenol and cyanuric acid, sulfonic acid, carboxylic acid and the metal salts of these organic acids, e.g. the metal salts of 1,3,5-tri- (m-phenoxyphenoxyphenyl) cyanurate, Hydroxy peroxides and peroxides.

.The long resistance (service life) of the migration layer is to be distinguished from the long durability (lifetime) of the latent electrical image. The former is subject to the Time, primarily before the generation of the latent electric seeing image, an impairment (deterioration) in the ability of the film to deliver images without loss of quality, even if the film is immediately after the creation of the latent electrical image is developed »the latter fails - one

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Impairment (deterioration) with the passage of time or against light or against both of the latent electrical image during the period before development,

Typical satisfactory amounts by weight for the additives are from about 0.1 to about 50 weight percent of the weight of the softenable Materials. Preferred ranges are from about 0.1 to about 7 weight percent. Above 7% by weight there is no noticeable one The extension of the resistance of the migration layer can be observed with increasing amounts of additives. as stated in the three American patent applications cited above with regard to the additives themselves, the softenable Material of layer 12 incorporated and used in accordance with the methods described therein.

The combination of long-lasting migration layers and stabilized latent electrical images can advantageously be combined even further with the deletion of the latent ones electrical images in the migration layer, as it is in the German patent application P 21 00 186.5 is described. A migration layer film (i.e. a film from a migration imaging device) with these three characteristic properties can be used in a camera, e.g. such as described in U.S. Patent 3,528,355 is used Such an arrangement allows the film to be overlaid prior to the formation of the latent electrical image keeping the camera in the camera for long periods of time, the possibility of the latent electrical image once it has been created is to stabilize and keep it on the film for long periods of time before development or ■ erasure, as well allows the latent electrical image to be erased from the film prior to development, if so desired. Such an arrangement is ideally suited for the control or monitoring of situations, v / ie e.g. for bank security cameras, for monitoring measuring instruments and

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Displays, such as in refineries, medical operating rooms, laboratories and the like. You can also use the camera and Use recording activities, for example, to monitor bank customers during business hours. To one uneventful day, the latent electrical images can be erased and the film can be reused for the next business day. When an unexpected event occurs, the stabilized latent electrical images can be used at any later time within the extended service life for the parameters used, as explained above. The electric latent images can also be used after exposure, for example The camera is intentionally or accidentally damaged in such a way that the film is activated by electromagnetic radiation or light if the stabilized latent electrical images are resistant to light. That anything can be done without any changes in the sensitivity, quality and resolution of the image appear.

It is believed that the phenomenon of stabilization of the latent electric image with the decrease in the surface charge, i.e., the charge remaining on the surface of the layer 12 of softenable material. the Decrease in the charge of the surface of the layer 12 of the softenable material occurs both with positive and with negative electric latent images, but it was found that in the case of negative electric latent images Pictures is done faster. It should therefore be pointed out that the duration of the stabilization stage is appropriate The particular softenable material used varies in that the rate of decrease in the charge of the softenable Material to softenable material varies. The mechanism that works during the decrease in surface charge occurs and allows or prevents the stabilization of the latent electrical image is not known, but it will assumed that during the decrease (of the disintegration) the upper

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surface charge the decreasing charge with the migration material and that it is this association that somehow stabilizes the latent electrical image and the longevity (durability) thereof is extended or the latent electric image is stabilized and extends its durability (life) by making it less photosensitive, or a combination both options, as the case may be.

It is also believed that during the decline (disintegration) of the surface charge, the decreasing charge in the background districts less or not available for the migration material becomes, even if the migration material is subsequently exposed and developed, creating the background areas become less photosensitive so that little or no washout of the stabilized latent electrical image occurs. It is also believed that combinations of the two proposed mechanisms for maintaining sensitivity properties by stabilizing, for example when stabilizing continuously toned images are·

FIG. 2 of the accompanying drawing shows how the image contrast density improves with the storage time in the dark. The time required to obtain maximum contrast and a minimum field can be shortened by a value between 10 and 10 ^P minutes up to a few seconds, by heating the Bi'lderzeugungseinrichtung for example, on a hot plate for about 2 seconds to 110 ⁰ C. It can be seen from this that the electric field decreases over time during storage in the dark, corresponding to the contrast naid.in.uin. The field curve supports the assumption that a charge depletion occurs

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Any suitable can be used in practicing the invention Combination of stabilization, charge polarity and evolution can be applied. However, it has been shown that specific combinations are preferred in order to achieve longer-lasting (more stable) latent electrical images. One such combination is the use of a solvent vapor stabilization step and a liquid development stage associated with a positive latent electrical image. Another such preferred combination consists in the application of a heat stabilization stage in connection with a heat development for negat5.ve latent electrical images. Although these specific combinations to achieve the greatest extension of the resistance to light and time are currently preferred, can be any combination of stabilization and development stages for positively or negatively charged latent electrical liilder are applied and the resistance (lifetime) of the latent electrical images to Time or light or combinations thereof can thereby be extended.

The method according to the invention for stabilizing latent electrical migration images is illustrated by the following examples, in which preferred embodiments of the invention are described, explained in more detail, but without being limited thereto. The parts and percentages indicated therein unless otherwise stated, refer to weight.

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example 1

A layered configuration imaging device was made by applying it about 2 microns thick Layer made from a commercially synthesized polystyrene / hexyl methacrylate copolymer with a weight average molecular weight of about 45,000 to a 0.076 mm (3 mil) thick Mylar polyester film substrate from DuPont, which is coated with a thin aluminum layer with a permeability to visible light of about 50% was. The migration layer adjacent to the free surface of the softenable layer was approximately 1/4 micron thick Layer of selenium particles about 1/4 micron in size, manufactured as specified in U.S. Patent Application No. 19,521.

The imager became uniformly electrical except for an applied field of about 50 volts / micron negatively charged, exposed to a photograph, whereby the

2 exposure in the exposed areas at about 10 erg / cm

400 nm to produce a latent, negatively charged electrical image. Those with the latent, negatively charged Electrically imaged imager was then placed on a hot plate for about 2 seconds in the dark Heated at 110 C to stabilize the image.

That the latent negative electrical image was then stabilized was conclusively demonstrated by the fact that the image forming device then evenly with white room light for a few seconds up to 1 minute or more

409843/1011

2415458

was exposed, which is normally (without the inventive Stabilization) would be sufficient to destroy the latent electrical image and then to have it by heating the image generating device on a hot plate at about 110 C for a period of about 20 seconds with or without switched on Room lighting was developed using heat. That included The heat-developed migration image obtained was comparable in terms of density, background and quality to that that was obtained when the latent image was immediately after the formation of the latent electric image in the dark was heat generated.

Example 2

The procedure described in Example 1 was repeated, this time using development heating instead of a hot plate was effected by a focused microscope illumination with a total exposure for a few seconds

2
exposure of more than 500,000 erg / cm at 400 nm.

The migration image obtained was the same as that of the example 1 comparable, which in view of the large amount of visible light that accompanied the heat generation, was extraordinarily surprising.

Example 3

The one described in the two created sections of Example 1 The procedure was repeated, with the exception of εΊηβ field strength of about + 35 volts / micron has been positively charged and

409843/1011

instead of heating, a slight softening was brought about for stabilization, which was achieved by exposing the imaging device with the latent electrical image to trichlorotrifluorate hand vapors for about 5 seconds (the liquid is commercially available under the name Freon 113 from DuPont), after which no noticeable
Particle migration was observed. Even the softenable one
Layer was different from the softenable layer of the
Example 1 insofar as the softenable sheet material
of Example 1 was mixed with about 5% Bakelite 5254, a p-phenylphenol-formaldehyde resin from Union Carbide »

That the latent positive electrical image was stabilized by the method described above was demonstrated by subsequently leaving the latent image forming device for several seconds
uniformly exposed to actinic room light which would normally (without the stabilization of the invention) be sufficient to destroy the latent electrical image
(to be washed out), and that they are then immersed in
liquid trichloroethane was developed. The resulting image showed no evidence of the room light exposure prior to development, although such exposure would normally destroy the image.

Example 4

The method described in example 3 vairde under education

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corresponding results were repeated, but this time the weak predevelopment softening was achieved by that he. immersing the latent electric image imaging device in Freon 113 for about 5 seconds and then took it out again. The solvent Freon 113 was intentionally chosen so that the matrix would not be sufficient at the time of immersion softened to allow migration, but the film only slightly softened to stabilize the to achieve a latent electrical image.

The films treated in this way could be handled in room light before development and it became one Extension of the life of the positive latent electrical image to about 24 to about 140 hours was observed.

Example 5

The procedure described in Example 1 was repeated with the same results, but this time do not place the imaging device on a hot plate for 2 seconds after the electric latent image is formed but kept in the dark at room temperature for about 24 hours, after which the imaging device with the stabilized latent electric image exposed to ambient light and developed.

Example 6 -'---

The procedure described in Example 3 was repeated, where-

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this time stabilization by contacting Freon 113 vapors with an exposure of about 1/2 second was replaced by 1,1,1-trichloroate hand vapors.

Example 7

The procedure described in Example 1 was repeated, this time between the stabilization of the latent electrical image and development heating stages was a period of more than a year.

Example 8

The procedure described in Example 5 was repeated, this time between the stabilization of the latent electrical image and development heating was a period of more than a year.

Example 9

The procedure described in Example 1 was repeated, this time the imagewise exposure through an optical plate took place, which had 300 line pairs per ml, and where between the stabilization of the latent electrical image and the development heating stage a period of more than 4 years ago. There was no loss of resolution.

A09843 / 101 1

Example 10

The procedure described in Example 1 was repeated, but with the following changes: The imaging device was charged uniformly to a field strength of about -40 volts / micron and passed through a 400 nm filter exposed uniformly at an intensity of about 10 ergs / cm for about 4 seconds, the imaging device was immediately stored in the dark for about 3 days at which time a residual surface charge potential of about -50 volts was observed became; the imaging device was then positively charged through a metal mask to remove the residual voltage to neutralize or delete in terms of images; the imaging device was then on for about 20 seconds develops heat for a long time at about 110 C, mainly in the negatively charged areas, i.e. in the areas that had not been image-wise neutralized, migration occurred.

Example 11

The procedure described in Example 1 was repeated, this time after stabilizing the latent electrical Image the stabilized latent electrical image by heating for about 2 seconds on a hot plate at 110 ° C Image by evenly charging the migration imaging device with positive charges and about 20 seconds prolonged heating to about 110 C has been quenched; then the in Sections 2 and 3 of Example 1 was

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repeated the procedures described in order to again generate a stabilized latent electrical image, which subsequently was developed.

In Examples 12 to 39 described below, numerous samples of the image forming apparatus described in Example 1 were used manufactured. The procedure described in Example 1 was repeated, but this time the the amount of negative charge used to form the latent electric image was varied. The exposure was carried out as in Example 1, but this time by a resolution plate with 228 line pairs per mm. The development was as in Example 1 after various lengths Periods between the stabilization of the latent electrical image and the development are carried out. In all Cases, stabilization was achieved by storing the imaging device effected in the dark either at room temperature or below room temperature. The room temperature varied between about 20 and about 25 C.

409843/1011

Examples 12 to

at
game
No. volt Storage time
tion in the dark
Stabilization (with
Room temperature if
nothing else stated
give is) Room lighting
clearing / time resolution
Line pairs
per mm Contrast density
White blue
light ■ light
V » 0.90 , * ■ ** 12th -80 0 228 0.47 0.71 LO
l - ¹ cn 13th -70 24 hours + / 1 min. > 220 0.40 ^ 0.78 I. cn
CO 14th ¹ -70 360 hours + / 1 min. > 220 ~ O, 26 0.86 15th -70 41 days + / 1 min. ' > 22O 0., 43 0.77 16 -70 8.5 months + / 1 min. > 22O 0.35 0.90 17th -70 0 - > 22O 0.45 0.79 18th -70 31 hours + > 220 0.43 0.85 19th -60 52 hours + > 220 0.44 0.78 20th -75 52 hours + > 22O 0.42 0.86 21 -70 8.5 months - > 220 0.40 0.95 22nd -85 0 > 22O 0.55 0.92 23 -80 6 months + / 1 min. > 220 0.60 0.92 24 -80 6 months + / 1 min. > 22O 0.60 0.92 25th -80 6 months + / 1 min. > 22O 0.60 0.92 26th -80 6 months + / 1 min. > 22O 0.60

Continuation of examples 12 to 39

At- . volt Storage time Room lighting resolution game tion in the dark clearing / time Line pairs No. Stabilization (with per mm Room temperature if nothing else stated give is) '27 -40 // U 0 - 228 28 -40 // u 22 hours (5 ⁰ C) - 228 O
CO 29 -40 // U 22 hours (5 ° C) + / 1 min. n.g. OO 30th -40 // u 22 hours - 228 CO 31 -40 // U 22 hours + / 1 min. n.g. O 32 -88 // u O - 228 33 -88 / / u 24 hours (5 ° C) - 228 34 -88 // U 24 hours - 228 35 -88 // U 24 hours + / 1 min. n.g. 36 -40 // U O - 228 37 -40 // U O + / 1 min. n.g. 38 -40 / λι 20 min. + / 1 min. n.g. 39 -40 / λι 5 min. + / 1 min. n.g.

Contrast density

White light

0.97 0.92 0.21 1.00 0.69 0.96 0.99 1.03 0.79 0.87 0.00 0.52 0.12

blue light

n.g. = not measured

CJl CO

Example 40

The image forming apparatus of Example 1 was used after Method described in Example 1 prepared. The imaging device was charged negatively to about -53 volts / micron and then image-wise exposure as in FIG Example 1 using a resolution plate with 322 line pairs per mm, a latent electrical image is generated and in the dark kept for about 24 hours to stabilize the latent electrical image. The imaging device was then charged to a field strength of about +53 volts / micron and heated to 110 C for about 60 seconds. The deletion was detected by heating the imaging device for about 60 seconds 110 C no migration occurred and no image was seen. There was a small positive residual voltage of about 3 volts established.

Example 41

Example 40 was repeated a total of fifteen times. After the sixteenth generation of the stabilized latent electric Image, the positive charge stage was omitted and the image-forming device was on by about 60 seconds prolonged heating of the same on a hot plate at about 110 ° C. Corresponding to the sixteenth imagewise exposure the resolution plate gave an image with a resolution better than 300 line pairs per mm. this

409 84 3/1011

demonstrates the reusability and the final development an image forming device having latent electrical images stabilized by storage in the dark.

Example 42

The procedure described in Example 40 was repeated, this time using the electric latent image instead of through 24 hour storage in the dark would be stabilized by heating at about 110 ° C for about 2 seconds and wherein this time the resolution plate had 228 line pairs per mm.

Example 43

The procedure described in Example 42 was repeated a total of twenty-five times. After the twenty-sixth generation of the electric latent image, the erasing step was omitted and the imaging device was developed by heating it on a hot plate at 110 ^° C. for about 60 seconds. According to the twenty-sixth imagewise exposure through the dissolution plate, an image was obtained with a resolution of about x 228 line pairs per mm. This demonstrates the reusability and ultimate development of an imaging device having latent electrical images stabilized by heating.

Example 44

The procedure described in Example 1 was repeated, \; o-

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IS

this time the even negative charge to one Field strengths of about -40 volts / micron led the image-wise exposure through a resolution plate with 228 pairs of lines per mm and stabilization was effected by keeping in the dark. After more than 4 years and 1 month passed, the image forming device became exposed to ambient light and as in Example 1 developed to obtain an image with a resolution of 228 pairs of lines per mm.

Although in the foregoing description of preferred embodiments of the invention, specific components and Quantities have been given, other suitable materials than those mentioned above can be achieved satisfactory results and different levels of quality be used. In addition, the materials used according to the invention can already be known or materials to be found can be added and the various process steps to achieve synergistic effects or others Improvements can be varied or otherwise modified in many ways

It goes without saying that various other changes may also be made with respect to those described and illustrated above Details', materials, stages and arrangements of parts can be made and such changes will be apparent to those skilled in the art of themselves upon reading the present invention and therefore also within the scope of the present invention fall.

409843/1011

For example, the stabilization can be carried out in this way that one can have an imaging device that is uniformly positively charged and uniformly an actinic exposed to electromagnetic radiation is image-wise softened by a mask with vapors. After imagewise softening by means of steam, the imaging device is kept in the dark for such a period of time that which is sufficient to keep the background areas (which have not been image-wise softened by means of steam) their latent exposure sensitivity to lose (i.e. to let a charge decay). The imaging device then has a stabilized latent positive electrical image which is later formed by a conventional migration imaging development process can be developed either by washing out or by means of steaming. That stabilized latent electrical image has a longer lifespan compared to light and compared to time.

Another example of a possible variation of the invention is the possibility to create a stabilized, latent, negative, electrical background image through uniform negative charging of an image forming device in the dark, imagewise heating of the image forming device using heat in the dark (e.g. for 2 seconds on a hot plate at 110 C or on a higher temperature for a longer period of time) and subsequent uniform exposure of the imaging device with ambient light or room light. At this time the background districts can be

A098A3 / 1011

bilization heat (e.g. by heating for about 2 seconds on a hot plate at 110 C). In conventional migration imaging development using heat (e.g. heating for about 20 seconds on a hot plate at 110 C), the heat stabilized background districts migrate, while the image-wise heated districts do not migrate.

Stabilization leads to such Alis guide forms in which the migration material is not electrically sensitive to light to the fact that the migration material takes on charges, which are usually present in an imagewise pattern are. In the embodiments in which the migration material is not electrically photosensitive, the applied field strength is usually either in the upper range of the above-mentioned applied field strengths or at even higher values. It is believed that these higher field strengths contribute to this result in the case of the use of an electrically photosensitive migration material.

As from the above migration image creation applications and as can be seen from the migration imaging patents referenced, the varying results depend of migration or non-migration in those struck by the light Districts that have varying results of migration or non-migration in those not struck by the light (dark) districts and the varying results of migration or non-migration of a non-electrically-photosensitive Migration material depends on many variables.

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These include e.g. the polarity of the charge, the size of the Cargo, the procedural steps used, the type of migration material and the type of softenable material. From this it can be seen that there are actually an infinite number of combinations of migration imaging processes associated with the stabilization of latent electrical images of the invention can be applied. Also, multiple stabilized, latent electrical images are generated. For example, a latent electrical image of a rectangle and that of a triangle are both formed and stabilized one after another on an image forming device, and upon development, both stabilized latent electrical images migrate in an imagewise fashion. Where two migrated If images overlap, the common district has a greater density than the non-common ones non-overlapping districts of the migrated images. It should be noted that multiple stabilized, latent electrical see images on a migration imaging device being used to produce continuous toned images can.

The ability to generate multiple stabilized images enables the invention to be applied to a wide variety of applications Areas. For example, manufacturers or suppliers of migration imaging devices, films and the like. In the form of a code recording or in the form of a tax form or any special Form, a special recording or a special image generate a stabilized, latent electrical image.

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gen and the migration imaging facility to consumers Selling. Consumers can then 'generate one or more stabilized latent electrical images, to complete the form, for example. In the usual migration imaging development migrate all stabilized latent electrical image areas and provide images that correspond to the seller's form and the like Consumer information.

Claims;

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Claims (1)

Claims Image forming methods characterized by the following Stages: (a) Manufacture of an image forming device having a Migration layer made of a migration material and a softenable material whose resistance to migration tion of the migration material can be reduced sufficiently to prevent migration of the migration material into the To enable inside of the softenable material (b) forming a latent electrical image in said imaging device and {p) stabilizing the latent electrical image. 2 · The method according to claim 1, characterized in that an electrically photosensitive material is used as the migration material. 5. The method according to claim 1 and / or 2, characterized in that that the electric latent image is formed by charging the surface of the image forming device and exposing it to light is generated with activating electromagnetic radiation, 4. The method according to at least one of claims 1 to 3, characterized in that the image generating device after the latent electrical image has stabilized, is exposed to activating electromagnetic radiation. 5. The method according to at least one of claims 1 to 4-, characterized by the additional stage (d) erasing the latent electrical image. 409843/1011 6. Migration layer, characterized in that it "consists of. Or contains a migration material and a softenable material whose resistance to the migration of the migration material can be reduced sufficiently, to allow migration of the migration material into the interior of the softenable material, and that it is a stabilized has a latent electrical image. 7. migration layer according to claim 6, characterized in that the migration material is electrically-photosensitive and that the migration material and the softenable material are in a layer configuration. 8. Image generation process, characterized by the following stages: (a) Manufacture of an image forming device having a migration layer made of an electro-photosensitive one Migration material and a softenable material whose resistance to migration of the migration material can be reduced enough to prevent migration of the migration material into the interior of the softenable material to enable (b) forming a negative latent electrical image in this image forming device, (c) stabilizing the latent electrical image in the absence of activating electromagnetic radiation and (d) developing the latent image electrical zv by sufficient reduction in V / iderstandes against the migration of the migration material into the interior of the softenable material to an imagewise migration of the migration material into the interior of the softenable material. enable. 409843/1011 - Ll - 9. The method according to claim 8, characterized in that, that to generate the negative latent electrical image, the surface of the image forming device with negative charges charged and activating electromagnetic Exposure to radiation. . 10. The method according to at least one of claims 1 to 5 and 8 and / or 9 * characterized in that the image generation -Gungseinrichtung with at least one additional stabilized latent electrical image is provided. 11. An image forming method characterized by the following Stages: . · (a) Manufacture an imaging device with a migration layer of a migration material and a softenable material, its resistance to the migration of the migration material can be reduced enough to prevent migration of the migration material into the interior of the softenable Materials to enable (b) forming a latent electrical image in said image forming device and (c) Stabilizing the latent electrical image by softening it of the softenable material without the resistance of the softenable material to the migration of the migration material reduce enough to allow migration of the migration material into the interior of the softenable material. 12. The method according to claim 11, characterized in that in step (c) the stabilization is carried out by means of steam will. 13. The method according to claim 11, characterized in that 409843/1011 in stage (c) the stabilization. using Heat is carried out. Method according to claim 11, characterized in that in step (c) the stabilization is carried out using a liquid. 15 · The method of claim 11 and / or 13 "characterized in that prolonged heating is stabilized at about 7O ⁰ C for about 10 seconds. 16. The method according to claim 11 and / or 15 »characterized in that that is stabilized by heating at about 110 ° C for about 2 seconds. 17 · Method according to at least one of Claims 11 to 16, characterized by the additional stage (d) erasing the latent electrical image. 18. The method according to at least one of claims 1 to 4 and 8 to 16, characterized by the additional level (d) reducing the resistance of the softenable material to the migration of the migration material by one To allow migration of the migration material into the interior of the softenable material. 19 Image generation process characterized by the following stages: (a) Manufacture of an imaging device having a migration layer of a migration material and a softenable material whose resistance to the migration of the migration material is sufficiently reduced 409843/1011 can, in order to allow migration of the migration material into the interior of the softenable material, (b) forming a negative electric latent image on said imaging device and (c) Stabilizing the negative electric latent image by keeping the imaging device in the dark for a period of at least about 200 minutes. 20. The method according to claim 19 »characterized by additional stage (d) erasing the stabilized electric latent image. 409843/1011