DE2249028A1 - PHOTOACTIVE POLYMERISATES WITH INDUCED EXOCYCLIC QUARTET CONCEPT - Google Patents

Description

October 6, 1972

Dr .-!, ',,. 1> ·. ν. .-.- r.'ti / i '
Münctiäa 22, Max "r, iii <i! Istr. 43

Xerox Corporation

Xerox Square,

Rochester, Hew York 14603

Photoactive polymers with induced exocyelic

Quartet concept

The invention is in the field of xerography and relates to a new photosensitive imaging agent and a method for its application, a mapping method.

In xerography, a jxerographic plate that contains a photoconductive insulating layer into a The image is transferred by first charging its surface evenly with electrostatic charge. Then the Plate a pattern of activating, electromagnetic Radiation, such as light, is exposed to the charge in the exposed areas of the light-conducting Isolator selectively degrades while a latent electrostatic Image remains in the unexposed areas. This latent electrostatic image can then developed to form a visible image by the deposition of finely divided electroscopic markers

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Particles on the surface of the phpfco-conductive insulating layer to build.

A photoconductive layer for use in xerography may or may be a homogeneous layer of a single material such as vitreous selenium be a composite layer that is a photoconductor and contains another material. Kind of compound photoconductive layer as shown in the Xerography used is disclosed in U.S. Patent 3,121,006 reproduced, which describes a number of binder layers, which finely divided particles of a photoconductive capable inorganic compound contained in an electrically insulating organic resin binder are dispersed. In its current trade form contains the binder layer zinc oxide particles that are uniform are dispersed in a resin binder, and is drawn up on a sheet of paper.

In individual, described in the patent mentioned The binder contains examples of binder systems Material that is unable to transport introduced charge carriers generated by the photoconductor particles over a substantial distance. Polly In the case of the special materials disclosed in the aforementioned US Pat continuous particle-to-particle contact located through the whole shift in order to be repeated for Operation to enable the charge reduction required. With the uniform distribution of photoconductor particles, as described in U.S. Patent, therefore, is usually a relatively high volume concentration of Pho to'l ei ter, up to about 50 percent by volume or

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more, necessary to be sufficient for rapid discharge Particle-to-particle contact of the photoconductor '. 13s it was found, however, that high photolei- in the binder layers of the resin type lead to the destruction of the physical continuity of the resin, what the mechanical "properties of the binder course considerably diminishes. Layers with a high photoconductor content are often brittle Binder layer of poor or lacking flexibility the end. On the other hand, the photoconductor concentration becomes considerable lowered below about 50 percent by volume, sinks the charging speed, which means a renewed or repeated Makes imaging difficult or impossible at high speed.

U.S. Patent 3,121,007 discloses another type of photoconductor which is a two-phase photoconductive binder layer with photoconductive insulating particles dispersed in a homogeneous, photoconductive, insulating Matrix, includes. The photoconductor is in the form of a particulate, photoconductive, inorganic crystalline pigment which, only generally disclosed, is present in an amount of about 5 to 80% by weight should be. The photo discharge should ^ by the combination of charge carriers in the photoconductive, insulating matrix material are generated, and from Charge carriers generated by the photoconductive crystalline Pigment incorporated into the photoconductive, insulating matrix are triggered.

U.S. Patent 3,037,861 discloses that polyvinyl carbazole shows a certain long-wave UV "3nipf finiteness, and recommends - the spectral "sensitivity through the access

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set of dye sensitizers to extend to the visible spectral range. Furthermore, we never recommend using other additives such as zinc oxide or titanium dioxide, even in conjunction with polyvinyl carbazole. 3s it is clear that the polyvinyl carbazole should be used as a photoconductor, with or without additives that extend its spectral sensitivity.

In addition, certain special layer structures, especially intended for reflex imaging, are proposed been. U.S. Patent 3,165,405, for example, employs one two-layer zinc oxide binder structure for reflective imaging at. It uses two separate, contiguous photoconductive layers with different ones spectral sensitivities to a particular yeast flexa formation sequence perform. The agent described here takes advantage of the properties of several photoconductive ones Schic]) th to take advantage of the combined benefits of the separate photoexcitation of the respective photoconductive To achieve layers.

From the above overview of the conventional composite photoconductive layers is.zu. recognize, that after exposure the Pbo conductivity in the layer structure by charge transport through the Mass of the photoconductive layer is achieved as in the case of vitreous selenium (and other homogeneous ■ layer modifications). In photo] openable binder structures using devices, the inactive, electricch Insulative Farze include, such as those in the U.S. Patent 3,121 QOG is conductivity

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or charge transport through high proportions of the photoconductive Pigments achieves what particle-to-particle contact of the photoconductive particles. In the case of photoconductive particles dispersed in a photoconductive matrix, illustrated e.g. in US Pat. No. 3,121,007, photoconductivity occurs through the generation of charge carriers both in the photoconductive matrix and in the photoconductive pigment particles.

Although the above patents refer to various Discharge mechanisms - through the photoconductive Referring to the layer therethrough, they generally suffer from a common defect, namely the photoconductive Surface is exposed to the environment during operation, and especially in the event of renewed xerography the abrasion, chemical attack, heat and many more Subject to exposure during repeated operations. These effects are characterized by a gradual Deterioration in the electrical properties of the photoconductive layer from, leading to formation of surface defects and scratches, limited areas permanent conductivity, which do not hold any electrostatic charge, and high dark discharge leads.

In addition to the above problems is the required photoconductivity ähigen layers that the Pbotoleiter either fo the layer 100 comprises, as in the case of the vitreous selenium layer, or that it preferably has a high proportion of the photoconductive material in the binder composition. The requirements for a

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all or a greater proportion of the photoconductive Photoconductive layer containing material "further restricts physical properties of the final plate, roller or belt by changing the physical properties, e.g. Flexibility and adhesion of the photoconductor to a carrier substrate mainly determined by the physical properties of the photoconductor and not from the farz or matrix material, which is preferably is present in a smaller amount "

Another form of a composite photosensitive Layer, which has also been considered by the prior art, comprises a layer of photoconductive material Material with a proportionate thick plastic layer is covered and mounted on a carrier substrate. U.S. Patent 3,041,166 describes such an arrangement in which a transparent plastic material is overlaid over a layer of vitreous selenium lies, which is contained on a carrier substrate. That Plastic material is said to be a large area for load carriers have the desired polarity. When operating, the free surface becomes the transparent The plastic is electrostatically charged to a given polarity. Then the arrangement becomes activating radiation exposed in the photoconductive layer creates a hole-electron pair. The electron moves through the plastic layer and neutralizes a positive charge on the free surface of the plastic layer, creating an electrostatic image is produced. However, this patent does not disclose any special plastic materials that are

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se work, and limits their examples to structures that are a photoconductor material for the top layer use.

The PR-PS 1 577 855 describes a compound photosensitive. Arrangement for special purposes that suitable for refiex exposure through polarized light is. One embodiment uses one layer dichroic, organic, photoconductive particles, which are arranged oriented on a supporting substrate, as well as a layer of polyvinyl carbazole over the oriented layer of dichroic material. When the oriented dichroic layer and the Polyvinyl carbazole layer charged and exposed to light which is perpendicular to the orientation of the dichroic Layer is polarized, both layers are practically transparent to the initial irradiation light. If the polarized light hits the white background of the document being copied, the light is depolarized, reflected by the array and absorbed by the dichroic photoconductive material. In another embodiment, the dichroic photoconductor is oriented over the polyvinyl carbazole layer distributed.

In the American patent applications 94 139, 93 994, 94 071 and 93 975 of December 1, 1971, photosensitive agents with functional materials are described. The first material is a photoconductor that is capable of generating and introducing excited holes and electrons in an adjacent, electronically active material. The electronically active material comprises a transparent organic material, the electromagnetic

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Radiation in the range of the intended xerographic Use practically not absorbed, but which is electronically active, indeia it dae injecting light-excited holes or electrons from the photoconductor and further the transport of these light-generated Charges enabled by the active material for the selective reduction of a surface charge.

The use of electronically active materials in combination with photoconductors in xerographic photoreceptors, as disclosed in the aforementioned applications is of enormous importance for xerography. For example, this type of photoreceiver can source down to 0.1 volume percent photoconductor to electronically active organic material, which makes it economical. Also offer these photoreceptors have excellent physical strength and flexibility, which enables their use under rapid repetitive conditions that are present in current xerographic processes are required.

So it is easy to see that there is an ongoing need to develop xerographic photoreceptors that quickly repeated those for the conditions Operation required electrical and physical Possess properties. In addition, the need for photoreceptors that incorporate new compositions is becoming electronic containing active organic materials and photoconductors, very highly valued.

The invention aims to provide a new, photosensitive, for repeated imaging (cyclic imaging) suitable device

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tion and a new imaging system as well as photosensitive Create means that develop an effective defect generation and transport through light. It also aims to introduce new photosensitive devices and a new method of image development photosensitive devices as well as new photosensitive devices Devices that are able to develop excellent mechanical properties, • create.

According to the invention, a photosensitive agent with at least two functional materials is provided. The first material comprises a photoconductive substance which is capable of producing holes when excited by light to generate and inject into an adjacent or adjacent, electronically active material. That electronically active material includes a transparent, organic, polymeric or non-polymeric material that practically not absorbed visible light or radiation in the range of the intended use, but this to that extent is active than it allows the injection of light-generated holes from the photoconductive layer and the transport of these holes through the active layer to selective discharge of a surface charge on the allows free surface of the active layer.

The invention encompasses the class of compounds including phenyl-substituted aromatics, in which the position of the phenyl group by eliminating the Fauptring from the aromatic, which has one more ring as the substituted compound.

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Special organic, electronically active materials that are suitable for the use in accordance with the invention, include 2-phenylnaphthalene, 2-phenylanthracenes, 2-phenylindole and its polymers. The chemical configurati Those of these three monomeric materials are as follows:

Understandably, the use of these electronically active substances enables a variety of Photoreceptor structures. Therefore, the electronically active substances can be used together with photoconductive material be in the form of a binder structure or a layer arrangement.

The active materials according to the invention do not act as photoconductors in the xerographic wavelength range Use. As stated above, hole-electron pairs in the photoconductive material are created by light, and the holes are then injected into the adjacent or adjacent electronically active material, and the hole draining sport takes place through the active material.

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A typical application of the invention includes the use of a sandwich cell or layer arrangement, which in one embodiment consists of a supporting substrate, e.g. a head who is on it contains a photoconductive layer. The photoconductive layer may, for example, be in the form of a Layer of an amorphous or vitreous selenium are present. "A transparent 2-phenylindole layer, which enables hole injection and transport, is used as a coating on the photoconductive selenium layer upset. The use of the transparent, electronically active layer made of 2-phenylindole is made possible it is desirable to take advantage of the provision of a photoconductive layer near the supporting substrate as well as from the protection of the photoconductive layer by an outer surface layer that allows the transport of holes generated by light from the Photoconductor enables and at the same time as physical protection of the photoconductive layer against ambient conditions works. This structure can then be exposed in a conventional xerographic manner, which usually includes charging, optical exposure and development.

Further features, details and advantages of the invention emerge from the following description of FIG Embodiments, especially in connection with the Drawings. It shows:

Fig. 1 is a graph of photosensitivity to the field dependence for an electronically active material alone and in conjunction with one Photoconductor;

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Pig. 2 is a diagram similar to Pig. 1 for a zv / eites active material;

Pig. 3 is a diagram of the absorption spectrum for Polyvinyl carbazole;

Pig. 4 is a diagram of the absorption spectrum for pyrene;

Pig. 5 bin 9 each a schematic representation of one. Embodiment of a device according to the invention or arrangement; and

Pig. Fig. 10 measured the discharge characteristics of the invention electronically active materials.

As defined herein, a photoconductor is a material that is in the wavelength range in which it is used v / should be grounded, electrically responds to light. In particular, it is a material whose electrical conductivity, corresponding to the absorption of electromagnetic radiation in a wavelength range in which it is used is to be increased considerably. This definition is made necessary by the fact that a large Number of aromatic organic compounds as photo ■ are known to be conductive or the photoconductivity is expected if they are exposed to strongly abraded UV, X-ray or irradiated gamma radiation. Photoconductivity in organic materials is a common phenomenon. Virtually all highly conjugated organic Compounds develop a certain level of photoconductivity under suitable conditions. Most of these organic materials have their main shaft 3 ängenanrr-R ^ rg in the UV-sensitive materials,

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and their excitation by short wavelengths is not particularly suitable for "copying of originals or color reproductions. Considering the general A predominance of photoconductivity in organic Connections based on the excitation of short wavelengths is therefore necessary in the context of this invention the term "photoconductor" or "photoconductive" so to understand that only those materials are included that are actually in the wavelength range in ' to which they are to be used, are stimulated by light.

Electronically active material as described in this invention ", also referred to as active matrix material when used as a matrix for a binder layer, is a practically non-photoconductive material that enhances the effectiveness of light-generated hole injection from the photoconductive layer to at least about 10 fo at field strengths of about 2x10 V / cm. This material is further characterized by the ability to transport the carrier of at least 10 cn at a field strength of no more than about 10 V / cm the active material is transparent in the wavelength range in which the arrangement is to be used.

The active transport materials to be used together with photoconductors according to the invention, are materials that are insulators in that they have an electrostatic charge on the active transport materials was applied, is not guided in the absence of exposure, to such an extent that sufficient for the formation and retention of an electrical

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static latent image on it. this generally means that the specific resistance of the active transporting terials at least about Should be 10 ohm-em.

V / ie can be seen from the above statements, are the vegetables for the active transport syotems Invention usable special materials incidentally also photoconductive when radiation from for electronic Excitation of suitable wavelengths is absorbed by them will. Photo excitation in the short wavelength range, however, which falls outside the spectral range, for clon the photoconductor to be used is for Performance of the arrangement or device is insignificant. It is well known that radiation must be absorbed in order to excite photoconductivity and "the doigen transparency criteria for the active materials state, that these materials are not in any essential extent to the photoexcitation of the photoreceiver in the used Y / ellenliingenbereich contribute.

The reason for the requirement that the active transport materials must be transparent is based on the knowledge that under all practical conditions the Effectiveness of the light radiation from the photoconductor in the active materials for visible, from the photoconductor absorbed radiation that the active material in, -any wavelength range, the visible or another, own photo sensitivity by far exceeds. This situation is illustrated by FIGS. 1 and 2, a comparison of the field dependence of the irradiation sensitivity with the photoconductor in r. as well as the material's own photosensitivity of

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show two electronically active materials disclosed in U.S. Patent Applications 93,994 and 94,139 are, namely polyvinyl carbazole (PYK) and polyvinyl pyrene (PYP), each measured on samples of 20 micron thickness on an aluminum substrate and manufactured according to the methods described in these applications. The curves for the layer structures of the same Materials with a 0.4 micron layer of vitreous selenium between the active material layer and the substrate are similar to those of the structure of Pig. 2. /

The data of the Pig. 1 and 2 are applied by applying the initial xerographic yield (g) determined as puncture of the applied field. The xerographic Aus The prey became from the initial unloading speed

(dY / dt).

calculated, where I is the incident, direct photon flux, d is the thickness of the layer ₅ έ is the dielectric constant and e is the electron charge. A unit xerographic yield would be observed if one charge carrier per incident photon were excited and moved through the layer. It is clear from Pig, 1 and 2 that the inherent photoconductivity of the active materials at their absorption wavelength peak (UY excitation) leads to yields that are considerably lower than the effective photoconductive materials with a two-phase structure, such as c e.g. through the layer structures below Use a.r.-

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Selenium layers with suitable active materials can be shown to achieve yields of approximately 0.70 at a level of about 10 v / cm, using an exciting wavelength within the visible spectrum (4000-8000 R).

Pig, 3 and 4 are absorption spectra for PVC and PVP at wavelengths of 2500 - 4000 J ?. From these spectra it is clear that PVK and PVP show negligible discharge, if at all, when they correspond to a wavelength of light useful in xerography, i.e. 3 i. 4000 - 8000 R ₁ can be used. The obvious improvement in performance resulting from the use of the zv / ex-phase systems of this type can best be realized when the active material is practically transparent to the radiation in a;:! Range, in which the Phofcoleiter used v to ground /: for every absorption of radiation desired by the active material prevents these Ctrahlung as ρh s ο ο 3 t eitf ähige ϊ, ίa te ri wο a 1-to-reach η _t them much more effectively · used. It follows from this that it is advantageous to use electronically active materials that are transparent in light sources in which the photoconductor is mainly stimulated. and especially in the wavelength range in which the photoconductor is to be used. The electronically active materials according to the invention also show transparency and a lack of absorption in the wavelength range of 4000 - 8000 R.

Referring to Pig. 5 shows the be / .ugosiffer 10 a preferred embodiment of the invention, which is a photographic

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sensitive agent in the form of a plate with a supporting substrate 11, which is covered with a binder layer 12. The substrate 11 contains preferably any suitable conductive material. Typical conductors are aluminum, steel, brass or the like. The substrate can be rigid or flexible and any appropriate strength. Typical substrates include flexible tapes or sleeves, sheets, webs or nets (webs), plates, cylinders and drums. The substrate or the carrier can also be a composite structure such as a thin conductive coating on a paper backing; a plastic, coated with a thin conductive layer such as aluminum or copper iodide; or glass, coated with a thin conductive coating of chrome or tin oxide. When using a transparent substrate it should be understood that imagewise exposure may be through the substrate or the backing layer the imaging agent can take place.

The binding layer 12 contains photoconductive particles 13 which are dispersed in a non-oriented arrangement in an electronically active matrix or a binder material 14. The photoconductive particles can consist of "any suitable inorganic or organic photoconductor and mixtures thereof capable of introducing holes created by light into the matrix. Typical inorganic materials include inorganic crystalline compounds and inorganic photoconductive glasses. Typical inorganic crystalline compounds include Cadmium sulfoselenide, cadmium selenide, cadmium sulfide and their mixtures. Inorganic photo-

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Conductive glasses include amorphous selenium and selenium alloys such as selenium-tellurium and selenium-arsenic. Selenium can also be used in a crystalline form known as trigonal selenium. Typical organic materials include phthalocyanine pigments, such as the X-Porm metal-free phthalocyanine, described in US Pat. No. 3,357,989, Metall-Phthilocyanine, such as copper phthalocyanine; Quinacridones (Monastral Hot, Monastral Violet and Monastral Red Y from DuPont); substituted 2,4-diamino-triazines of U.S. Patent 3,445,227; Triphenodioxazines, U.S. Patent 3,442,781; polynuclear aromatic quinones (tndofast double scarlet, indofast Violet Pigment B, Indofast Brilliant Scharlach and Indofast Orange from Allied Chemical Corp.). This compilation of photoconductors is in no way limiting, but merely illustrates suitable ones Materials. The dimensions of the photoconductive particles is not critical, but particles of one size in the range of about 0.01 - etv / a 1 micron give particularly satisfactory results.

As previously stated, the photoconductive materials are used according to the invention in a non-oriented manner. "Not oriented" means that the pigment or the photoconductive material is isotropic with respect to the exciting electromagnetic radiation, in that it is to everyone Polarization of the stimulating radiation is equally sensitive.

The electronically active matrix material 14 includes organic substances 2-phenylnaphthalene, 2-phonylan-lhracene

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and 2-phenylindole, which are the introduction of light excited voids from the photo-conductive pigment support and the transport of these defects through the active matrix material to the selective Unloading a surface charge enables “Ausserdera are condensation, addition and other types of polyacrylate of 2-phenylnaphthalic 2-phenylanthracene and 2-phenylindole are electronically active and fall into the Field of Invention »

"As stated above, any polymer (a polymer is a large molecule that is built up by repeating small, simple chemical units)" whose repeating unit represents the suitable, electronically active organic monomer according to the invention, ie, 2- Phenylindole ₀ contains ", can be used within the scope of this invention." Therefore, the scope of this invention does not specify the type of polymer that can be used as the matrix material "polyester, polysiloxanes, polyamides, polyurethanes and epoxides as well as block, grafts - or random copolymers (which contain the repeating aromatic unit) are examples of the different types of polymer that can be used. In addition, suitable mixtures of active polymers with inactive polymers or non-polymeric materials can also be used »

In general, the active layer is transparent or virtually not absorbed in at least a substantial part of the range of about 4000 - 8000 R acts

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but still in such a way that the introduction and the Transport of imperfections is made possible, which within this wavelength range by the photo] rapid pigment parts have been produced.

An upper limit of the volume concentration or occupation rules on the photoconductor is determined by various factors: in particular (1) are ernsthi.it affected by the stage at which lii ^«1 physical Eigensolnften of the polymer; (2) the stage at which significant particle-to-particle contact transport occurs; and (3) the stage at which conductive pigments such as 7, .B. trigonal selenium, insulin-like imperfections, migration occurs during charging. The latter two factors often result in an inability to restart. In general, the upper limit for the photoconductive pigment or particles must not exceed about 5 vol. $ Of the binder layer to get the best combination of

to achieve physical and electrical properties. A lower limit for the photoconductive particles of about 0.1 VoI .fo the binder layer is necessary 'to ensure that the light absorption coefficient sufficient to give a significant carrier generation. In order to achieve a closely equivalent discharge rate under both Li (! ^ Conditions, it is necessary to work in a region of the volume occupancy where the penetration depth of the light penetration is close to the center of the layer.

A full explanation of the charge properties an active binder plate in terms of volume concentration is disclosed in US Pat.

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the content of which is therefore to be included here.

As disclosed in U.S. Patent Application 93,994, a critical range is from about 0.1 to 5 $ by volume of the photoconductor required to take advantage of the electronically active matrix-binder composition / according to to achieve the invention.

The strength of the binder course is not particularly critical. Layer thicknesses from about 2 to about 100 microns have been found to be satisfactory, with a preferred thickness of about 5 to about 50 microns being particularly leads to good results »

With reference to Pig 6, the reference numeral 10 designates an imaging means in the form of a plate with a supporting substrate 11 and a binder layer 12 thereon and an active layer 15 over the binder layer 12. The substrate 11 is preferably made of any suitable conductive material ₉ such as SB "The ₀ for that. Substrate which were called lig _o 5,

The binder layer 12 contains photoconductive particles 13 !, those without orientation in a binder 14 statistically distributed sxndo The photoconductive particles can be made from any suitable inorganic or organic photoconductor and mixtures thereof exist, suitable photoconductive Similar materials include those identified above for the structure of FIG. 5.

The binding material 14 can be any electrically insulating - Resin include, such as "B. those in the aforementioned US Pat. No. 3,121,006, or any suitable

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te active material, which may be the same as or different from that used for layer 15. Will uses an electrically inactive or insulating resin, 1ε? T it essential that between the photoconductive Particle-to-particle contact exists. This requires the photoconductive material to be present in an amount of at least about 25 Vol. ^ Of the binder course without limitation of the maximum amount of the photoconductor in the binder layer. If · the matrix or the binder is an electronically active one Material must include the photoconductive material only about 1 vol 55 or less of the binder course without Limitation of the maximum amount of photoconductor in the Include binder course. The thickness of the photoconductive layer is not critical. Layer thicknesses of about 0.05 "to 20 microns have been found to be satisfactory with a preferred thickness of about 0.2 to 5 microns giving good results.

The electronically active layer 15 comprises the electronically active substances 2-phenylnaphthalene, 2-phenylanthracene, 2-pheny] indole and their polymers. These substances are able to support the introduction of excited by light from the defects photoleitfahigen layer and rmögliehen the transport of these defects through the organic layer to selectively discharge a surface η1a d 1 η 1 g ζu e.

The ak fciνe Schich ■;., Dieη t η not η only for the transport of Holes, but also protects the photoconductive Layer against abrasion or chemical attack and therefore extends the operational life of the imaging, Photoreceiver.

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In general, the strength should be electronic active layer be about 5 "to about 100 microns, but strengths outside this range can also be used. The ratio of the thickness of the active Layer to the photoconductor layer should be between about 2: 1 to 200: 1 are held «

In a further embodiment of the invention, the structure of FIG. 6 is modified in order to ensure that the photoconductive particles are in the form of continuous chains through the thickness of the binder layer 12. This embodiment is shown in FIG. 3. 7 _} "in which the basic structure and materials are the same as in Fig. 6, except that: the photoconductive particles 13 are in the form of continuous chains.

On the other hand, the photoconductive layer can be completely off the practically homogeneous, non-oriented, photoconductive Material, as s.B. a Schichfaus amorphous selenium or selenium alloy, or a powdery one or sintered photoconductive layer, such as cadium sulfoselenide or phthalocyanine. These Modification is illustrated in Fig. 8, where a photosensitive means 30, a substrate 11 having a homogeneous photoconductive layer 16 and an overlying active organic layer 15 comprises.

Another variation of the one in the Pi {;. 5, 6, 7 and the binder and layer configurations described include the use of a barrier layer 17 sn of the substrate-photoconductor intermediate f j; ^; che a «The;.; e A. no rc! -

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tion is illustrated by the photosensitive means 40 in FIG. 0 , in which the substrate 11 i: ir: ci the pboto-conductive layer 16 by a barrier; 3c 11ic] 11 17 are faithful. The barrier layer works by: - the introduction of charge carriers from the substrate, into which the photoconductive layer is prevented. Iode's suitable barrier material can be used. Typical fabrics are nylon, spoxide and aluminum oxide.

"'Ic listed above is the photoconductive material, regardless of whether it is in the form of a pill or as a homogeneous one 3-layer, in η η χ not οrieηtierter form applied; aηdt. Under not oriented is to understand that the pigment

or the php to "capable layer isotropic" with respect to the egg extro- io

is stimulating, natural radiation, i.e. it is equally sensitive to any polarization of the excitation 31rah3 uηg.

In general, the binder and sheet structures of the invention require that the photoconductor of the electronically active materials of the invention be selected or suitably configured so that charges are generated by radiation for which the active materials are transparent or non-absorbent . This range corresponds to a length of about 4000 to about 8000 years. which is the preferred range for xerographic applications. In addition, a Phdolleiter should also address all V / ellen length from 4000 to 8000 R if panchromatic stimulation is required. All photoconductively active material combinations according to the invention lead ~

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ren to the injection and subsequent transport of holes through the physical interface between the photoconductor and the active material.

The following examples further set forth specific and preferred embodiments of the invention a method of manufacturing a photosensitive Means with a photoconductive layer attached to a layer of the electronically active material according to the invention. Unless otherwise stated, the percentages relate to weight. The examples serve only to illustrate the invention without limiting it.

Example I.

A plate or layer structure similar to that in! Ig. 9 consisting of a 20 micron thick layer of 2-phenylindole applied to a 1 micron thick layer of amorphous selenium deposited on an approximately 5 χ 5 cm (2 2 inch) HSSA glass substrate manufactured as follows:

1) 0.2 micron sine polyvinyl carbazole barrier

Starch is produced on one surface of the HSSA substrate by dip-coating the substrate in a 1% solution of polyvinyl carbazole in toluene. After the coating, the substrate is dried in the air for 16 hours at 10O ^{0 O.}

2) A photoconductor layer made of vitreous selenium is deposited using a vacuum deposition technique, e.g.

'disclosed in U.S. Patents 2,753,278 and 2,970,906

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de, applied to the barrier layer. The selenium layer is applied to a thickness of about 1 micron. V / hile the deposition is the temperature dee Substrata at about 25 to 55 ⁰ C. The source of selenium is kept at 26C ⁰ C, and the evaporation is carried out at a pressure of 1 χ 10 ^-6 Torr.

3) The coated plate is then placed in a second vacuum chamber and 1 g of 2-phenylindole is placed in the evaporation boat. The organic material was then vacuum evaporated onto the selenium layer at a pressure of 5x10 ~ Torr in 30 minutes at a source temperature of about 50 C while the substrate was kept at a temperature of about 10 ⁰ C. This results in a 2-phenylindole layer approximately 20 microns thick. The obtained layered plate is allowed to cool in a vacuum at room temperature for 24 hours. _x

Example II

A layer structure similar to that of Example I with a 35 micron 2-phenylnaphthalene layer mounted on a 0.5 micron thick selenium layer deposited on an NBSA glass substrate is produced using the vacuum evaporation method shown in the example. In the formation of the layer of 2-phenylnaphthalene the pressure is 6x10 Torr, and the deposition is for 150 minutes at a source temperature of 50 C and a substrate temperature of O ⁰ C. performed.

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The discharge characteristics of the electronically active plates produced according to Examples I and H ₉ are measured. In detail, the layer structures are spray-charged to a selective negative potential Y and exposed to a monochromatic light source of 4000 α "at" a flux of 2 × 10 'photons / cm see. At this wavelength, the electronically active materials are in accordance with. Invention practically non-absorbent, and the selenium is stimulated by light. Me initial discharge rate C ₁ CJ ₁ Y ₁ ) _fn _Q of each plate at the selected potential

was according to P. Begensburger in "Optical Sensitizai: ion of Charge Carrier transport in PYK ", Photochemistry and Photobiology 8, pp. 429-40 (JToveober 1968) Enjoyed techniques that are included here in some cases * - " are related.

A number of initial discharge rates at selected potentials for each plate, ^ is measured, divided by the thickness of the electronically active organic layer and on a logarithmic scale against the corresponding applied field E is plotted as This type of representation shown in Fig. 10 shows the Felofi-dependency of the charge mobility through the The respective electronically active organic layer »curve Λ represents the mobility of the photo-generated solution Defects caused by selenium. The ideal electronically active material in combination with selenium would be the Closely approximate the field dependence curve Λ for selenium.

'. Referring to Fig. 12, curve B, it can be seen that the with Selenium and 2-phenylnap.htha.lin coated plate.

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measured discharge in the applied fields over e Uwa 1 Yo]. t / wed crown. Ausserdora indicates the curve that ss da s 2 -P he ny '.! η α υh11 ία 1 iη P eh 1 ste 11 en transported adequately enough to lead to acceptable residual voltages after the discharge, compared to a pure selenium photoreceptor layer. Curve C, the selenium-i'-pbenyl iridol-noticeably dead plate, shows an even lower Gronz field in which the charge is mobile] ·: «: 't; occurs, and therefore a minimum of root voltage remains on discharge.

Without the "3 τ fi η d υ η g (i ara 1 1 f f. E r, I '/, \ 11 ege η, η achf ο 1 gend a theory" is discussed, and the electronically active Ei go η Explain the properties of the invention ineosons substances τ, ν. In 5s it became clear that pyrene, tetracene, ^{1,2-benzene-! n J} b}] racene and 3, 1-3enzcarbazole are electronically active ; iν siηd, u η d the \ νic 1 ί I-ige criterion for this is that

ΛuGna öS oor

Cr "

■ you k {; r ο η e 11 d. e 1 ο]; a 3 i s i e ru η g

Tetracene

1,2-ben ^ anthracene

The extent of electron delocalization is, by way of introduction, a.?,. benzoj. the sextets in tetracene and two in 1,2-benzanthraea shown (E. dar, "Polycyclic I'ydrocarbojjü", Academic Press, 1% 4, Hew York). Arrows:; ind. inserted: ^T , oic] met, to indicate the movement of the sextet over the rings of connection. These sextets' consist of three movable '/ i'-'- octron pairs, from

3098 18/1023

BATH ORIGINAL

two of which are fixed to the individual rings, while the rest of the pair can move freely across the system. As the ring system over which this third pair moves becomes larger, the '/ (electrode delocalization increases. In other words, the Ίί -electrons are less shielded from the positive nuclear charge than in a smaller ring system, its G-renze is Benaol.

In 1,2 ~ benzanthracene there are two sextets, both in are able to steer a mobile pair of electrons into the central ring of the ring system. That leads to one induced sextet in the ring. The double bond in the 3,4-pitch is more or less formal, because it is through the response developed at these positions. Spectra show that the delocalization is taking place, by itself when the -CH = CH-G group is removed. That means, 2-phenylnaphthalene has a similar electronic Spectrum as 1,2-benzanthracene. In particular, it is believed that the p orbitals of the phenyl group match those of the substituted molecule due to the coplanarity of the rings in a y-axis! The electrons can shift over the entire plane of the molecule. Thats why. when comparing 2-phenylnanhthalene

309818/1023

with benzanthracene, above, a similar electron activity to predict. The same applies to 1,2-benzetracene and 2-phenylanthracene.

One arrives at a similar picture if one looks at carbazole "considered. That means ^ a benzoid ring on one Angular positioning will increase the delocalization of the whole aromatic system. Looking at the structures ■

and

3,4-benzocarbazole

1,2-benzocarbazole

it is shown that in both molecules the angled Ring '' T-Slectron controls the carbazole system. One might expect that even if the carbon atoms are in the 1,2- or 3,4-position of the corresponding benzcarbazole would be eliminated, this contribution would still exist.

On the basis of these considerations Hesse explain that the resulting compounds, 3-phenyl- and 2-phenylindole, compared to the IndoVselbot, superior transport

and develop transmission.

309818/1023

3-phenylindole

2-phenylindole

Two other compounds in which the nitrogen of the Oarbazole is replaced by oxygen or sulfur, i.e. Dibenzo £ bdJ furan and Dibenzo jbdj thiophene can be used as active substances are considered. The interesting, phenyl substituted compounds are;

and

3-phenylbenzo (Jo] furan

2-phenylbenzo (Vj furan

thiophene

2-phenylbenzofobjthibphen

Examples of further compounds which meet this requirement are given below together with the stasis compound from which the laienyl-substituted compound is derived.

309818/1023

BATH

G ': -' i π ;; ; i γ c ν bi η dung discarded connection

! ..), G-eon: - '^ hvvi; en 1 -Phony] pheneans

1, 2-Be η 7. tet ra cg η 2-plienylanthracene

1, 2 -3 e η ζ ο j; e η I seen

and

2-P he ny11 et τ a ce η

Na ph Llio-C 1 ■, 2 '-3, 4) -pyrene 3-? LienylpyrGn

3 0 9.8 18/1023

NaphthoC 2 ^! »1'-5.4) pyrene

4-phenylpyrene

Naphtho- (1 ^I , 2'-2,3) -fluoranthene α-phenyl fluoranthene

Naphtho- (2 ', 1'-2,3) -fluoranthene 3-Phenylfluoranfchen

30 9818/1023

Naphtho- (1 ', 2'-3,4-) carbazole

3-Pheny! .Carba zol

Naphtho- (2 ', 1-3,4) -t: arbazol 4-phenylcarbazole

* The -OE-CF group eliminated in every compound is circled 'iat'.

The invention also includes equivalent structures in which II is replaced by S or O. The effectiveness this substance is dependent on the aromatic structure of the molecule and therefore functional groups can be considered Substituents such as alkyl, amino, nitro, etc., which include the Facilitate chemistry of production or contribute advantageously to the mechanical properties of the polymers, containing these as repeating units, introduced into the phenyl aromatics without loss of activity will.

The class of compounds and polymers prepared using these are part of the repeating Unit can be described as follows: an aromatic system including heterocycles and those with functional groups & ls substituents to which or which the 'ΰΤ-electron delocalization by Phenyl substitution is increased. The position of the phenyl

3098 18/1023

249028

group can be described as formed by eliminating two carbon atoms and the fixed double, -V-connection in the Y / angle of the main ring from the aromatic hydrocarbon which has one more ring than the substituted compound. In _{1,2-benzanthracene, Z 0} Bo leads to the elimination of the two carbons and the fixed double bond, which shows reactivity corresponding to an olefin, to the active molecule 2-phenylnaphthalene. -

Briefly, the invention includes the class of compounds to which phenyl-substituted aromatics belong * where the position of the phenyl group is determined by eliminating the main ring from the aromatic, the one Ring has more than the substituted compound.

Although specific components and proportions have been recited in the foregoing description of preferred embodiments of the invention, suitable materials and processes other than those recited above can be used with similar results. In addition, other substances and modifications can be used which synergistically improve, increase or otherwise modify the photoempiinäliche agent and the method for its application. For example, it is a transparent substrate, such as a plastic coating with a thin conductive coating

309818/1023

BAD ORiQiNAL

224902ε

Used by aluminum or tin oxide, the structure can be converted into an image by exposure through the substrate be convicted. In addition, an electrically insulating substrate can also be used if desired. In this case the charge can be applied to the imaging agent by double corona charging, as is customary in the field. Further modifications using an insulating substrate or without a substrate at all involve applying the imaging agent to "a conductive pad" or plate and the charging of the surface during contact with the base. Hach the imaging process the imaging agent can be removed from the conductive pad.

30981 8/1023

Claims (32)

Patent claims My imaging agent with a 'layer of photoconductive Material and an adjacent layer of an electronically active organic material over the photoconductive Layer lies, the photoconductive layer generating and injecting holes when excited by light and the active organic material is the injection of photo-excited holes from the photoconductive Support layer and can transport the holes through the active layer, the active layer at least one of the substances 2-phenylnaphthalene, 2-phenylanthracene, Contains 2-phenylindole and its polymers. 2. Means according to claim 1, in which the photoconductive Layer contains photoconductive particles dispersed in a binder. 3. Means according to claim 1 or 2, in which the photo ™ conductive layer / a practically'.homogenes, photoconductive Contains material. 4. Composition according to one of claims 1 to 3, in which the photoconductive layer is on a load-bearing Substrate is located. 5. Means according to claim 4, in which the substrate is electronically conductive. 3 0 9 818/1023 6. Composition according to claim 5, in which the photoconductive layer is on a substantially transparent one supporting substrate is located. 7. Composition according to claim 1, in which the photoconductive material vitreous selenium, a selenium alloy, trigonal selenium, cadmium sulfoselenide and / or the X-form contains metal-free phthalocyanine. 8. Composition according to one of the preceding claims, in which the material of the active layer is a phenyl-substituted one Contains aromatics, in which the position of the phenyl group by eliminating the main ring of the Aromatic, which has one more ring than the substituted phenyl compound, is determined. 9. Agent according to one of the preceding claims, in which the active layer 3-phenylindole, 3-phenylbenzo [blfuran, 2-phenylbenzo [b] furan, 3-phenyl {V] thiophene, 3-phenylbenzo \ b \ thiophan, 2 -FhenylbeBZo £ b] thiophene, 1-phenylphenanthrene, 2-phenyltetracene, 3-phenylpyrene, 4-phenylpyrene, α-phenylfluoranthene, ^ -rienylfluoranthene, 3-kienylcarbazole and / or 4-phenylcarbazole. 10. Mapping verges, thereby g e k β η η ζ e i c h ne t that an imaging medium is acceptable any one of claims 1 to 9 uniformly negatively charged on the free surface of the active layer and the charged layer is a source of activating radiation which the photoconductive layer absorbs and for which the active layer is practically transparent and non-absorbent, exposed, the- 309818/1023 This irradiation takes place in the form of a pattern of light and shadow which is optically thrown onto this layer, whereby holes created by light in the photoconductive layer are introduced into the active layer and transported through it to form a latent electrostatic Image on the free surface of the active layer. 11. The method according to claim 10, characterized in that the latent image is developed into a visible image. - · 12. The method according to claim 10, characterized in that g e k e η η shows that the activating radiation used is radiation in the visible spectrum. 13. The method according to claim 10, characterized in that a source for the activating radiation for the range from about 4000 to about 8000 R is used. 14. The method according to any one of claims 10 to 13, characterized in that the photoconductive Layer - is used on a supporting substrate. 15. The method according to claim 14, 'characterized in that g e k e η η draws that an electrically conductive substrate is used. 30 9 818/1023 16. The method according to any one of claims 10 to 15, characterized in that in the material the active layer is a phenyl-substituted aromatic in which the position of the phenyl group is through Eliminating the main ring from the aromatic which contains one more ring than the substituted phenyl compound, is intended to be used. 17. The method according to claim 10, characterized in that the latent image for production of a visible image is developed and charging, exposure and developing are at least one more Times is repeated. 18. The method as claimed in claim 17, characterized in that a source for the activating radiation in the range from about 4000 to 8000 R is used. 19. Imaging means, characterized in that a binder layer is provided which contains photoconductive particles distributed in an electronically active organic matrix material, the photoconductive particles being able to generate and inject holes when excited by light and the active matrix material supporting and injecting holes from the photoconductive particles the holes can easily pass that the photoconductive particles are present in an amount of about 0.1 ibs 5% by volume of the binder layer and that the active matrix contains 2-phenylnaphthalene, 2-phenylanthracene, 2-phenylindole and / or polymers thereof. 309818/1023 20. The composition of claim 19, wherein the photoconductive particles in an amount of about 0.1 to 1.0% of the binder course is present. 21. Composition according to claim 19, in which the binder course located on a substrate. 22. Composition according to claim 21, in which the substrate is electrically conductive. 23. Means according to claim 19, in which see the binder course located on a transparent substrate. 24. Means according to claim 19, in which the photoconductive Layer of vitreous selenium, a selenium alloy, trigonal selenium, cadmium sulfoselenide and / or X-Porm contains a metal-free phthalocyanine. 25. Composition according to claim 19, in which the active Matrix material a phenyl-substituted aromatic in which the position of the phenyl group is eliminated the main ring from the aromatic, the one more ring. as the subst /. ^ has an extended phenyl linkage will contain. 26. Agent according to one of claims 19-25, in which the active matrix material is 3-phenylindole, 3-phenylbenzo £ bjfuran, 2-phenylbenzo [bJfuran, 3-phenyl [V] thiophene, 3-phenylbenz.ofb [thiophene, 2-phenylbenzo [b3thiophene, 1-phenylphenanthrene, 2-phenyl tetracene, 3-heli yl pyrene, 4 ~ phenyl pyrene, α-phenylfluoranthene, 3-phenylfluoroai. chen, 3-phenylcarbazole and / or contains 4-phenylcarbazole. 309818/1023 27 · Imaging method, characterized in that with a means according to one of the claims 19 to 26, the binder layer is uniformly electrostatically charged on a supporting substrate, the charged Layer of a source of activating radiation that contains the hiotoconductor particles absorb and which the active organic matrix material does not absorb, is exposed, wherein this irradiation in the form of a pattern of light and shadow is optically projected onto the layer, whereby injected the photoconductive holes generated in the photoconductive particles into the active matrix material and be transported through this to form a latent electrostatic image on the surface of the binder layer, 28. The method according to claim 27 »characterized in that the latent image becomes a visible Image is developed. 29 · The method according to claim 28, characterized in that the charging, irradiation and Develop to be repeated at least one more time. 30. The method according to claim 27 »characterized in that the irradiation in the range of about 4000 to 8000 & occurs. 31. The method according to claim 27 »characterized in that an active matrix material! which a phenyl-substituted aromatic in which the position of the phenyl group by eliminating the main 309318/1023 224 rings from the aromatic which has one more ring than the phenyl-substituted compound, is used. 32. imaging material according to one of claims 1 to 18 or 19 to 30, characterized in that the photoconductive material in the layer or the photoconductive particles in the matrix material in unoriented form. 3098 18/1023