DE1772523C3 - Electrophotographic process - Google Patents

Description

irradiated image-wise during or after softening.

2. Electrophotographic method according to claim 1, characterized in that in the The time between the start of charging and the end of the imagewise exposure is the softenable Layer is additionally irradiated uniformly, the uniform irradiation being carried out in this way is that only a polarity reversal but no discharge of the photosensitive particles takes place

3. The electrophotographic process according to claim 1 or 2, characterized in that the softenable layer by ¹ Z ₂ to 10 seconds long exposure to a solvent vapor is softened.

4. Elektrophctographisches ^ experience according to claim 1 or 2, characterized daü a solvent permeable breakable layer is used.

5. Electrophotographic method according to claim 1 or 2, characterized in that the softenable layer is softened by heating at 50 to 80 ° C for 1 to 10 seconds.

6. Electrophotographic process according to one of Claims 2 to 5, characterized in that that with 10.76 to 10 760 lux sec. evenly and with 10.76 to 1076 lux seconds. pictorial is exposed.

7. Electrophotographic method according to one of claims 1 to 6, characterized in that that as light-sensitive particles or substances ZnO, phthalocyanines, Se, azo dyes, Indigo or a mixture thereof is used.

50

The invention relates to an electrophotographic process in which a recording material has a support and a softenable layer on or in which light-sensitive particles are contained are, or on the one layer that can be broken by the electrostatic forces of a charge image a photosensitive substance is applied, evenly charged, with activating electromagnetic Irradiated radiation imagewise, and the softenable layer by heating or treatment is softened with a solvent.

Such an imaging method is known from FR-PS 14 66 349. In this procedure, a recording material is used, which consists of a conductive layer support and one on top of it Image produced by this process is a negative image of the positive original image. Those parts of the Photosensitive material that does not migrate to the conductive layer support can through the Solvent can be washed off along with the softenable layer. In other development processes the softenable layer can remain at least partially on the base.

In general, three different recording materials can be used in this imaging method wsrden: A recording material made of a conductive support with a layer of a softenable one Substance and a breakable and preferably particulate layer of a photosensitive Substance on the softenable layer or embedded in it near its surface Recording material in which the photosensitive particles within the on a conductive The softenable layer located on the substrate is dispersed, and a recording material is present on which a conductive support is coated with a layer of a softenable substance, on one of which Layer of photosensitive particles and on top of this a second layer of a softenable one Fabric is applied. The term "breakable layer" refers to a layer or a layer Substance that breaks during development and a migration of its parts onto the substrate in a pictorial manner Allows distribution

This mapping process thus consists of a combination of the process steps of forming a Charge image and development with a solvent liquid or a solvent vapor, with heat or combinations of these types of softening to make the image visible. In proceedings The generation of the charge image in a non-photosensitive or neutral way can be breakable Layers and photosensitive particles can be used to form images, as described in US Pat French patent 14 66 349 is described, the charge image in the most varied of ways can be generated, for example by image-wise distributed charging by means of a mask or stencil, by generating a charge image on a special photoconductive insulating material layer according to customary electrophotographic reproduction technology and transfer of this charge image to the recording material by bringing both layers very close to one another and that described in U.S. Patents 2,982,647, 2,825,814 and 2,937,943 The rollover method is used. Furthermore,

gene charge patterns in a specially shaped electrode or electrode combination corresponding Configuration by a discharge process pach the US-PS 30 23 731, 29 19 9.> 7, 30 01 848 so- «Ije by electron beam recording after the US-PS 31 13 179 are generated.

In another embodiment of this mapping method creates an image through the selective disruption of a particulate matter on or } n one that is electrostatically deformable or capable of wrinkling Layer generated. There is a difference here from those described above Method da.in that the softenable layer in connection with a breaking of the particulate Substance is deformed, as is described in more detail in FR-PS 15 07 656.

The properties of the images produced by this process depend on the charge, the Exposure and development as well as the respective combination of process steps. Some the achievable properties are high density, halftones and high resolution. The picture is in general a fixed or unfixed particulate image with or without a portion of the softenable Layer and non-migrated layer parts on the recording material. It can for example Used in microfilm, hard copies, optical masks, and adhesive printing processes will.

For some photosensitive ones preferably to be used Particle types result in a positive-negative image with uniform charging of the Recording material, imagewise exposure and development. For many types of image production, it is desirable positive images from a positive original and negative images from a negative original to manufacture.

The invention is based on the object of producing positive images from positive originals as well as negative images from negative originals, the image quality being improved and a mechanical shutter is not required for exposure.

In a method of the type mentioned, this object is achieved in that the softenable Layer of the recording material is irradiated imagewise during or after softening.

The softening of the softenable layer can be achieved by treatment with a solvent liquid or a solvent vapor, hot water or combinations of these agents. The pictorial Exposure during the soft state gives images of improved quality as well as positive images of positive originals using recording materials with which previously only the production of a negative image from a positive optical image was possible. In addition to uniform charging, uniform exposure can also be performed, this step can be omitted for some light-sensitive, breakable substances.

Further configurations of the invention relating to the method are given in FIG specified in the subclaims.

The invention is explained in more detail with reference to the embodiments shown in the drawing. It shows

F i g. 1 an embodiment of a recording material used in the method,

F i g. 2 the electrostatic charge in the process,

F i g. 3 the uniform exposure in the process,

F i g. 4 shows a preferred embodiment of the imagewise exposure in the process;

F i g. 5 A and 5 B show a further embodiment of the imagewise exposure and development in the Procedure and

ίο F i g. 6 shows the cross section of the FIG. 1 shown Recording material after its processing. In Fig. 1 is an embodiment of a recording material 10 shown, which consists of a layer support 11 and an electrically insulating

ίο there is softenable layer 12, which at their Surface contains a breakable layer of photosensitive particles 13.

The layer carrier 11 can be electrically conductive or non-conductive. Make conductive layers easier

ao in general the electrostatic charge of the Recording material and then consist of copper, brass, nickel, zinc, chromium, stainless Steel, conductive plastics and rubbers, aluminum, steel, cadmium, silver or gold. the

a5 support can have any suitable shape, for example it can be used as a metal strip, sheet, plate, spool, cylinder, drum, endless belt, Möbius strip or similar. If desired, the support can have a conductive coating contain an insulator such as paper, glass, or plastic. Such supports consist of practical transparent tin oxide on glass, an aluminized polyester film or one with copper iodide coated film made of polyethylene terephthalate.

Electrically non-conductive layers can also be used, creating a large Number of film-forming substances, such as plastics, can serve as a layer carrier 11.

The softenable layer 12 can be made of any suitable material that is in a solvent liquid or exposure to solvent vapors or heat or combinations thereof Medium, soluble or softenable and also during the generation and development of the charge image is practically electrically non-conductive. Typical such substances are a partially hydrogenated resin triester, an alkyd resin, silicone resins, sucrose benzoate, a polystyrene-olefin copolymer, a strong branched polyolefin, a styrene-vinyltoluene copolymer, a polystyrene-olefin copolymer, epoxy resins, a phenylmethyl silicone resin, a bisphenol-A-epichlorohydrin-epoxy resin as well as a phenol-formaldehyde resin, a copolymer of styrene and hexyl methacrylate synthesized in a known manner, a poly diphenylsiloxane synthesized in a known manner, a synthesized in a known manner Polyadipate, acrylic resins, thermoplastic resins a chlorinated hydrocarbon, thermoplastic « Polyvinyl resins and mixtures of these substances.

The above Slofigruppe is only an example for substances that are ver usable for the softenable layer 12.

This layer can be of any suitable thickness with thicker layers generally requiring a greater charging potential. In general, before preferably a layer thickness between 1 and 4 Mi krön is used.

The fabric for layer 13, the parts of which are *

The image formation on the support can be made of any suitable photosensitive, frangible Be formed material. For images of the highest resolution and density, the breakable substance should be particulate be, it can also be a continuous or semi-continuous breakable layer for example according to a "Swiss cheese pattern" that breaks during the development step and one Migration of their parts on the base in a pictorial configuration allows.

Any suitable photosensitive, frangible material can be used. Typical such substances are inorganic or organic photoconductors.

Typical inorganic photoconductors are amorphous selenium, amorphous selenium alloyed with arsenic, tellurium, and antimony or bismuth, etc., cadmium sulfide, zinc oxide, cadmium sulfoselenide as well as many others. In the U.S. Patent 3,121,006 are typical inorganic photoconductive ones Pigment substances listed. Organic photoconductors are special azo dyes, such as the ao Barium salt of l- (4'-methyl-5'-chloro-azobenzene-2'-sulfonic acid) -2-hydroxy-3-naphthenic acid, C.I. No. 15865 and a pyranthrone-like pigment quinacridone-like pigment, the beta form of copper phthalocyanine, C.I. No. 7410, the alpha form of metal-free phthalocyanine, C.I. No. 74100, commercially available indigo, yellow pigments, produced according to FR-PS 14 67 288, the X-form metal-free phthalocyanine, produced according to the FR-PS 15 08 173, quinacridonequinone, sensitized polyvinylcarbazole, 3,3'-methoxy-4,4'-diphenyl-bis (l "azo-2" -hydroxy-3 "-nyphthaniid), CI. No. 21180, l, 2,5,6-di (D, D'-diphenyl) -thiazolanthraquinone, C.I. No. 67300 and mixtures of these substances. The above list of organic and inorganic Photoconductors are only examples of materials that can be used.

It has been found that some photosensitive materials make particle migration patterns more exceptional Produce quality, such as B. amorphous selenium, and the preferably used organic substances generally produce negative images of positive originals when uniform charging, exposure and development according to FR-PS 14 66 349 is carried out. With these photosensitive The new process enables substances to carry out a positive-positive imaging process.

It was also found that other photosensitive substances, such as zinc oxide, sometimes depending on changes in the production of the recording material and the three basic process steps of charging, imagewise exposure and development according to FR-PS 14 66 349 a positive-positive image or enable positive-negative imaging. The new process can be used for these photosensitive substances in order to ensure a positive-positive image with a higher quality than known processes. Furthermore, it was found with these substances that the same effect is achieved even if the uniform exposure is dispensed with. Although the reasons for this have not yet been fully clarified, it is assumed that the higher dark conductivity of these substances is decisive for this. In the case of substances that contain amorphous selenium, a uniform exposure must be carried out in the further development of the process in order to have sufficient conductivity and stronger binding of the 1-adune to the breakable substances.

In addition to the arrangement shown in FIG. 1, there are others Embodiments of the recording material possible, for example one in which the Layer of the photosensitive, frangible substance also disperses throughout the softenable Layer consists. Furthermore, a recording material in which the photosensitive Fabric is arranged as an intermediate layer between two layers of the μ soft fabric that is on are applied to the substrate.

The breakable layer of the in F i g. 1 may be fabricated by any suitable method will. Typical processes are vacuum evaporation according to FR-PS 14 66 349, in which one breakable layer less than 1 micron thick, preferably of amorphous selenium on top of the softenable Layer is applied. The breakable layer can also be cascaded, sputtered and so on be further formed, as shown in FR-PS 14 66 349. The strength of the breakable Layer is preferably less than about 1 micron, although layers 5 microns thick on some fabrics also showed good results. If a binder layer is used, it can be produced according to US-PS 31 21 006 take place.

In Fig. 2 shows the uniform electrostatic charging of the recording material, for which purpose a corona discharge device 14 is used, which extends from left to right over the recording material is passed over and applies a uniform charge to the surface of the layer 13. Other charging methods, such as B. by friction or induction according to US-PS 29 34 649, are applicable. The surface tension of the layer 13 can be between a few volts and 400 for image generation Volts. In the case of positive polarity, the voltage should be between about 100 and 300 volts in order to be optimal Get results. With negative polarity, optimal results are achieved if the surface tension of layer 13 is between about 25 and 150 volts. It should be noted that the steps of Procedure are described one after the other, but they can also overlap to different degrees. For example, the uniform exposure can occur during or after charging.

If the layer carrier 11 consists of a non-conductor, for example, the recording material can be charged by touching the substrate with a conductive part and charging according to FIG. 2 take place. Further in the electrophotographic Technique for charging the recording materials with non-conductive layers known methods can be applied. For example, a charge of the recording material is by double-sided Corona discharge possible with two corona discharge devices on either side of the recording material release opposite charges hand over.

In Fi g. 3 is the uniform exposure of the recording material 10 shown with activating radiation 18. Suitable exposure levels are in generally between about one to ten times the pictorial attention shown in FIG. 4 shown is. Preferably, the uniform exposure is 10.76 luxsec. up to 10760 lux sec. or more performed in order to obtain the best possible image quality.

Any suitable activating electromagnetic Radiation can be used. Typical types of radiation are incandescent lamp radiation, X-rays, Charged particle rays, infrared, ultraviolet, etc.

It is shown that the applied according to FIG electrical surface charges with the uniform exposure according to FIG. 3 in the frangible layer 13 have migrated into it. Although this representation is based on an assumption only they are useful for understanding the processes involved, because a stronger bond of the electrical Charges on the layer 13 due to movement into this layer results from the uniform Exposure as shown in FIG.

In Fig. 4 is the recording material 10 during imagewise exposure to activating radiation 15 and softening by immersion shown in a solvent liquid 19 for the softenable layer 12. The liquid is »o in the container 20. The electrical charges within the layer 13 now move out of this in the image-wise exposed areas out and into the softenable layer 12, with only in the unexposed areas of the layer 13 still remain charges. This representation is also based on an assumption, however, is useful in understanding the procedure.

It is believed that there are actually three phases in imagewise exposure during softening appear. Once the layer 15 is first softened in the manner shown, and the charge the imagewise exposed parts of the layer 13 migrate into the layer 12 or are injected into it, secondly, the unexposed parts of the surface of the layer 13 which still contain charges migrate the substrate 11; thirdly, when immersed in the solvent liquid, it dissolves completely of the layer 12 as well as washing off the non-migrated particles in the exposed parts of the surface causes.

In the case of the in FIG. 5 A illustrated embodiment, the imagewise exposure can be carried out, while the recording material 10 by the action of solvent vapors for the Layer 12 is softened. The imagewise exposure during or after softening can be used here a treatment with a solvent liquid can be carried out by removing the recording material 10 for example temporarily with a solvent for the softenable layer 12 according to FIG. 5 B is brought into contact, for which purpose it is placed in the container 23 with the solvent 24 for the layer 12 is immersed. In this embodiment only the first or the first and the second phase occur while the recording material is in the solvent vapors, what of their Strength depends. The second and third or only the third phase then occur in the subsequent one Solvent treatment.

The duration of the treatment with solvent vapors, the preferred type of softening, depends of the solvent used, the vapor concentration, the substance of the layer 12, the imagewise exposure level and other factors, but preferably it is about Vi second up to about 10 seconds to get optimal quality images

In many cases it is preferable to have the imagewise exposure at the same time as exposure to solvent vapors, as in Fig. 5 A shown. However, the exposure can also be after the Softening by the vapors take place while the softenable layer 12 is still in the soft state. In this case, however, the exposure should preferably take place within a few minutes after the softening step be performed to ensure sufficient softness for image formation.

If the imagewise exposure lasts longer than the time required for the photosensitive substance to migrate to the substrate 11, for example if the softenable substance is already in the soft state, the migration time becomes the effective exposure time, so that a precisely timed mechanical shutter is not required. The migration time can be ¹ Ao second.

Besides the preferred softening with a solvent liquid or solvent vapors any other suitable type of softening may also be used during or before the imagewise exposure will. Typical options are heat softening, for example by heating the softenable fabric to about 50 ° C to about 80 ° C within a time of about 1 to about 10 seconds as well as combinations of solvent liquid or steam and heat. The intended softening step can be omitted if the softenable layer is already in the soft state, for example shortly after production, when the layer is still so soft that a special softening step is not required.

The process according to the invention ensures that the exposed in the softened layer Area parts the layer 12 is dissolved and the layer 13 is washed off in these area parts. However, this does not take place in the unexposed parts of the area, but rather the layer 13 migrates onto the Layer support 11 and adheres to this so that they are in the form of an image pattern 22 made of frangible fabric is present upon removal from container 20 or 23 in the manner shown in Figure 5B. The picture 22 in the form of the letter "A" is a positive image from a positive original. For example, there can be « The original should be a large black or dark "A" on a lighter or white background, with · with the method according to the invention in contrast to the known methods instead of a negative image: results in a positive image from parts of the layer 13, which are in the form of the letter "A" on the through the Layer support 11 formed background wandered.

It should be noted that the one shown in the figures! Step of completely washing off the softener The raw material and the fragile material that has not migrated is a contrasting image with little or no results in no veil and therefore in simple! Way making pictures excellent; Quality enables, however, to produce one; usable image in the method according to the invention is not absolutely necessary. For example, even charging with or without < Even exposure and image-wise exposure in the soft state of the softenable layer without a subsequent wash off a usable positive positive particle migration image, which despite de:

in the exposed parts of the surface, parts of the layer not removed by special observation methods can be made visible, for example by focusing the reflected from the support Light on a viewing screen. A solvent can be added at any time thereafter Such a particle migration image can be applied to make it even more washed off the image in Fig. 6 shown type to convert. For this, the applied solvent does not have to be insulating conductive liquids can also be used.

It is also shown that the exposed parts of the surface of the frangible substance form a particle migration image can be removed by abrasion to give a visible image. You can also be peeled off by an adhesive, so that complementary positive and negative images result.

It is not yet fully understood why the uniform charging, the uniform exposure in some cases, the softening of the softenable layer and the imagewise exposure in the soft Condition of the layer result in an improved positive-positive image. A theoretical explanation here strong layer of a partially hydrogenated resin triester on a polyethylene terephthalate film is rolled on with a thin, transparent aluminum coating. A breakable layer of Seier with a thickness of about 0.2 microns is applied to this layer by the method described in FR-PS 14 66 349 Deposition method with neutral Ga: is used.

The recording material is then in the dark to a positive surface tension of about 60 volts charged by means of a corona discharge device. Then the charged recording material even with about 107.6 Luxsec. exposed.

The recording material is then exposed to a positive optical image in the dark, the exposure in the exposed areas of the area being about ¹⁰⁷ ' ⁶ . Luxsec. and the exposure time is about 1 second depending on the softening time,

ao during immersion in vapors of 1,1,1-trichloroethane is carried out. The exposure takes place at a distance between the recording material from about 5 cm from the liquid level, where

Solvent is softened. The particles in the exposed parts of the surface of the layer 13 lose it Warding ability before the layer support 11 reach. Only the unexposed parts of the layer 13 experience a sufficient force and migrate to the substrate of the recording material.

As can be seen from the following examples, the method of the present invention is positive-positive imaging not only on the one shown in FIG. 1 shown recording material is applicable, but works also with one in which the photosensitive, breakable substance 13 is preferably in particle form is dispersed in the layer 12.

The liquids 19, 24 and 26 for softening the layer 12 are only intended for this layer, but not the layers 13 and 11 dissolve and have a sufficiently high electrical resistance to to prevent the charge from being discharged from the layer 13 * before it reaches the layer carrier 11 Typical solvents for the various substances in layer 12 are, for example: acetone, trichlorethylene, Chloroform, ethyl ether, xylene, dioxane, benzene, toluene, cyclohexane, 1,1,1-trichloroethane, pentane n-heptane, trichlorotrifluoroethane, carbon tetrachloride, thiophene, diphenyl ether, cis-2,2-dichloroethylene, Nilromethane, η, η-dimethylformanide, ethanol, ethyl acetate, methyl ethyl ketone, ethylene dichloride ' Methylene chloride, trans-1,2-dichloroethylene, and mixtures these substances.

The following examples further describe the process of positive-positive imaging. Parts and percentages relate to the weight, unless otherwise stated. All Exposures are made with a tungsten filament lamp. The examples make some preferential Execution of the procedure.

Example I.

A recording material of the type shown in FIG. The type I illustrated is produced by making an approximately 2 mi- \ ^ - ^Ζ " ^{Γ wall} [ ^{ung of the b} ^ ^h
aluminized substrate required

" ™ ^ ^Bh ^

Substance on
H is.

took.

The recording material is then used for about 2 seconds to wash off the resinous triester and of the non-migrated frangible material immersed in cyclohexane. On the aluminized layer

wearer results in a dense and evenly tinted, Excellent positive image, which is directly visible and also used as a projection slide can be.

Example II

The process according to Example I is repeated with the difference that the layer 1.1 consists of a Myrol-vinyltoluene copolymer consists of solvent vapors are generated with trichlorotrifluoroethane and the developability 1,1,1-tricnloroethane is.

Example III

The procedure in the first two paragraphs of Example I "" level is repeated. The ge recording material is immersed in nutty trichlorotrifluoroethane in the dark and exposed to an optical image, the illumination ^ _{1076 lux and that of the wander} uug

Exposure time from about ¹ Zi is ₀ second, about 3 seconds, the Aufzeichnungsma-

s? rh _Ρ ^{? 11} Ιΐ, ^{Γ mssi} & ™ removed. It gives a picture of the type described in Example I.

Example IV

i / \ irl ^{k0Xid having a} particle diameter of about SOM v * ^hich of Glasträgerteilchen having about Male Slf P ^ ¹ is SW worn, some 6s' is ken £ v ^r ,, ^ ^dle rtäche of about 2 microns star-SLt? ^{FROM the teaw} eise hydrogenated resin toS5..i. » . is cascaded ^{on an} aluminum-HaSSS ° · ^{β on} 8 ^{e braht.} The doctor's nests ^ ¹ ^ trichloro-trifluoroethane steaming »

softens between the cascading processes, so that an approximately 1 micron thick layer of zinc oxide forms in or on the Harz triester.

The recording material is then uniformly electrostatic to a surface tension of charged about -50 volts by means of a corona discharge device. Then it will be with an optical Negative image with about 538 lux seconds. exposed while, as described in Example I, the trichlorotrifluoroethane vapors exposed for about 10 seconds.

The recording material is then trichlorotrifluoroethane Immersed for about 3 seconds, so that a negative image results, which with the image generated in Example I is comparable, but has a higher quality than an image generated with a uniformly charged, exposed and liquid-developed recording material according to the FR-PS 14 66 349 was generated.

Example V

The alpha form of metal-free phthalocyanine CI No. 74100, having a particle size of about ¹ micron in diameter, supported by glass support particles about 50 microns in diameter, is cascaded over the surface of an approximately 2 micron thick layer of the Hsrztriester 10 on aluminized polyethylene terephthalate fill. The resin triester is softened with trichlorotrifluorethane vapors between the cascades so that an approximately 1 micron thick layer of phthalocyanine particles results in or on the resin triester.

The recording material is then uniformly electrostatically applied to a surface tension of about -60 volts by means of a corona discharge device at about 430 lux seconds. charged, taking them. as described in Example I, exposed to the vapors of trichlorotrifluoroalane for about 5 seconds.

The recording material is then in trichlorofluorethane immersed for about 3 seconds, so that the result is an image which is in its quality with that of Example I is comparable, but has a higher quality than that of the known Process with uniform charging, exposure and liquid development produced image.

1 sheet of drawings

Claims (1)

Patent claims: 1. Electrophotographic process in which a recording material with a layer support and a softenable layer on or in which light-sensitive particles are contained, Who is on the one layer that can be broken by the electrostatic forces of a charge image a photosensitive substance is applied, evenly charged, with activating electromagnetic Radiation irradiated imagewise, and the softenable layer by heating or Treating with a solvent softens _.:_j JJ ι- _-i --- ι *.! - OJj ₆₁₅ brought layer of a softenable, i.e. also a soluble substance, which contains light-sensitive particles. A charge bond is generated on the photosensitive surface, for example by uniform electrostatic charging and imagewise exposure to activating electromagnetic radiation. The recording material is then developed by exposing it to a solvent which only dissolves the softenable layer. The light-sensitive radiation hit by the softened and dissolved AiIi ^ ₁ , Jidurch and leave behind on the conductive layer substrate an image consisting of migrated particles, which corresponds to the radiation pattern of the original - .. ,, / _ * -: - t .. r »""U; m can then on the