DE3108156A1 - LIGHT-DEVICE DEVICE IN LAYER DESIGN AND ELECTROPHOTOGRAPHIC IMAGING METHOD USING SUCH A DEVICE - Google Patents

Description

description

The invention relates to an imaging device that responds to light, in particular of a layered construction, and to the use such a device in electrophotographic imaging systems.

Electrophotographic copying and particularly xerography as described in US Pat. No. 2,297,691 the development of an electrostatic latent image on a light receiver consisting of a conductive substrate, which has a layer of photoconductive insulating material on its surface. In some cases there is a thin barrier provided between the substrate and the photoconductive layer, for example made of aluminum oxide, to a feed to prevent charge from the substrate in the photoconductive layer when the plate surface is charged.

In a known method, a latent image is formed on the light receiving surface in that first the Plate is charged in the dark, for example by exposure to a cloud of corona ions, and that the Imaging is done by exposing the plate to a light and shadow image, optionally to the light receiver to discharge, creating a latent image corresponding to the shadow areas. This latent electrostatic Image is then developed by treating the plate surface with a developer material such as toner is brought into contact due to the electrostatic attraction adheres to the latent image. The toner image can then be transferred to a carrier, for example paper followed by fusing of the toner into the paper to create a permanent copy.

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The imaging surface of the light receiver is then made by any known method including charging cleaned, the purpose of cleaning basically being residual toner and / or the latent electrostatic Remove image. The electrostatic latent image can also be used in other ways. For example, can Electrostatic scanning systems can be used to read the latent image or can transfer the latent image onto other materials can be transferred and saved according to the TESI process. The developed image can also be read or left on the photoconductor can be fixed when the imaging layer is not used again.

Many different types of light receivers can be used in the above described method and are well known, such as photoreceptors containing, for example, organic materials such as polyvinyl carbazole, inorganic materials such as selenium and selenium alloys, and mixtures thereof. Light receivers are also known where. the generation of the charge carriers and the transport of the charge carriers take place via discrete and adjacent layers. Light receivers are also known which have a coating layer made of an electrically insulating polymer material, a large number of imaging processes having been proposed in connection with this coated light receiver, one of which is described, for example, in Electrophotography _/ Focal Press Limited, London 1975 by RM Schaffert. In one method, a non-ambipolar photoconductor is used, in which the charge carriers are injected from the substrate electrode into the photoconductor surface. In order to obtain high quality images in such a method, the injection electrode must meet the condition that it efficiently and uniformly injects the charge carriers into the photoconductor.

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Imaging methods and devices have already been described mainly aimed at layered structures and mainly made of organic materials consist, for example, the transport layer can consist of an organic material and various types of Injection electrodes can be used. Although these devices work adequately, it is still necessary to to further develop the photoreceiver devices and in particular the inorganic photoreceiver devices in layered construction, that they show excellent injection properties and therefore are used in electrophotographic systems can be used to maintain high quality images for a long time.

The invention provides a layered inorganic photoresponsive device that can be used in various Imaging systems, for example in electrophotographic Systems, can be used in which a double charge sequence is used, the inventive Device is characterized by the fact that it consists of a substrate or a base support that has one on its surface Layer of hole injection materials made of trigonal selenium or gold carries a hole transport layer which is in working connection with the hole injection layer, the transport layer consists of a selenium-arsenic alloy doped with a halogen, and the percentage by weight of the selenium is between about 99.5% to about 99.9%, while the weight percentage of arsenic is between about 0.1% to about 0.5%, a charge generating material used as a coating is provided on the transport layer, this material consists of inorganic photoconductive substances, and a protective layer, i.e. a layer of an insulating organic synthetic resin overlying the charge generation layer. About 10ppm to about 200ppm halogen material

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are present in the transport layer.

In a preferred embodiment of the invention, the substrate is made of a conductive material such as If the hole injection layer consists of trigonal selenium or gold, the hole transport layer consists of aluminum a selenium-arsenic alloy doped with a halogen, the proportion by weight of selenium between about 99.5% to about 99.9%, while the weight fraction of the arsenic is between about 0.1 to 0.5%, and is the halogen material -in one Amount from about 50ppm to about 100ppm present, while the a charge-generating layer consists of a selenium-tellurium alloy and the coating layer consists of a polyester or polyurethane material consists.

The hole injection material made of trigonal selenium can thereby be formed that the selenium layered on a holding substrate is evaporated in a vacuum. The transport layer will then layered over the injection layer of trigonal selenium, whereupon a coating of the one that generates the charges Layer is formed on the transport layer and optionally the organic resin insulating layer on which the charge generated Layer is formed as stated. In general, there is a strong bond between the hole injection layer and the substrate and the hole injection layer and the transport layer. The subsequent deposition of the transport layer and that generating the charges The layer is applied in a vacuum chamber, i.e. in a known 61 cm vacuum coating device. The heating of the substrate during the deposition of the layers is preferably carried out using a temperature-controlled mandrel, which is with the back of the substrate is in contact. This heating method In contrast to glow discharge heating, for example, the additional oxide formation remains on the etched Aluminum area as small as possible and allows a better

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Control of the substrate temperature during the entire photoconductor deposition procedure. Depending on the type of desired The process conditions can accordingly change in the manner indicated in the photoreceiver device.

The substrate, which in one embodiment consists of a flexible Sheet metal consists of high-purity aluminum / usually has to be treated in order to allow the high-purity selenium to crystallize trigger. The highly polished aluminum sheet is rubbed down with Scotch Brite, for example, until the surface is matt is obtained, whereupon it is etched with an Ef ferallösung. If in another embodiment If a massive cylindrical drum is used as the substrate, the aluminum drum becomes a weak caustic first Etching using a known mixture of trisodium phosphate, sodium carbonate and water exposed.- Before the A further etching with an Efferal solution can also be used.

The injection layer of trigonal selenium, which is in working contact with the substrate, for example an aluminum plate, is formed in that a weighed amount of high-purity selenium is evaporated from a separate vessel. The amount weighed out will depend on the particular construction of the vacuum coating apparatus, but is calibrated to provide the desired strength of the trigonal selenium on the substrate as indicated below. The substrate temperature during this vapor deposition is kept in the ideal case, at about 95 to about 120 ⁰ C. The selenium evaporation rate is adjusted so that the condensation rate of the vapor on the substrate is not greater than the conversion rate of the selenium from the amorphous to the crystalline state at the substrate temperature, since this ensures that

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the crystalline injector layer made of trigonal selenium at the same time is formed upon contact. If it is possible that an amorphous layer will be deposited, which will subsequently slowly converts to crystalline form, then there may be a sharp decrease in hole injection efficiency and / or a decrease in the adhesion of the hole injection layer to the substrate may result.

The gold injection material can be formed by subsequently applying gold in a vacuum coating device a carrier substrate is evaporated. The gold is treated with a glow discharge to make the hole injection layer more powerful close. This means that there is little additional oxide formation on the etched substrate, i.e. the aluminum kept as possible and the gold is made more active as a hole injection material. The transport layer is then layered on the gold injection layer, whereupon the charge generating layer is applied to the transport layer and optionally an organic synthetic resin insulating layer is applied to the charge generating layer, as it is stated. During the final curing of the light receiving device a solid bond is generally formed between the hole injection layer made of gold and the Substrate and between the hole injection layer and the transport layer. Depending on the type of light receiving device desired the process conditions can vary accordingly.

As with trigonal selenium, the substrate can be a flexible sheet made of high-purity aluminum and should be in front of the Gold precipitation will be treated. For example, a polished aluminum sheet is rubbed with Scotch Brite! until cally results in a matt surface finish, after which © is carried out in etching with an Efferal solution. If with another

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Embodiment a massive cylindrical aluminum drum is used as a substrate / this is initially a weak one subjected to caustic etching using a known mixture of trisodium phosphate, sodium carbonate and water. A further etching with an Efferal solution can also be carried out before use.

The transport layer, which consists of a selenium-arsenic alloy doped with a halogen, is evaporated by methods currently in use to obtain a layer of the desired thickness, for example up to about 60 µm, as described below. The amount of alloy present in the vapor deposition boat depends on the particular design of the coating apparatus and other process variables, but is calibrated to provide the desired thickness of the transport layer. The chamber pressure during the vapor deposition process is in the order of magnitude of less than 4 10 Torr. The vapor deposition can be completed over a period of about 15 to about 25 minutes, with the temperature of the Tigels containing the molten alloy rises during this period from about 25 ° C to about 300 ⁰ C. Other time periods or temperatures which lie outside these ranges can also be used, as is readily apparent. During deposition of the transport layer is desirable for the substrate temperature in the range of about 60 ⁰ C is maintained to about 8O ⁰ C.

The layer generating the charges, which in one embodiment consists of a selenium-tellurium alloy with 75 to 80% selenium and 20 to 25% tellurium is formed by grinding the selenium-tellurium alloy and making pellets from the base material be formed so that a layer of the desired thickness results in the specified manner of, for example, up to 5μπι. The pellets are evaporated from sticks using a time temperature program designed so that the fraction

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nation of the alloy is kept as small as possible during evaporation. In this way the concentration of tellurium across the charge generating layer can reasonably be kept close to the composition of the pellets, ie a flat tellurium profile can be maintained. A typical time temperature program for the Tigel for this step is in the formation of a the charge generating layer in a thickness of Ο, βμΐη in about 12 run to about 15 minutes, during which time increasing the Tigeltemperatur of 25 ⁰ C to 385 ° C.

In some cases there may be a variation in the surface tellurium content above or below 25% to a higher or lower photosensitivity and correspondingly higher or lower Lead to dark decay rates.

The device described above consists of a substrate coated with an injection layer of trigonal selenium or gold which in turn is coated with the specified transport layer, with a charge-generating layer on the transport layer Layer is provided, can then be coated with an insulating layer made of an organic synthetic resin. Typically, a layer with a thickness of about 5 μm to about 25 μm is made of a polyurethane resin by spraying on a resin solution, although other types of resins and methods of resin deposition may be used.

In a preferred example of the working method, the above-described light receiving device is constructed in a layered manner charged a first time with electrostatic charges of negative polarity, then a second time with electrostatic charges Charges of positive polarity are charged to essentially neutralize the charges on the electrically insulating Surface of the element, and the element is then

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send with a pictorial pattern of activating electromagnetic Exposed to radiation to thereby form an electrostatic latent image. This image can then be developed to generate a visible image that is transferred to a receiving element. The imaging element can can then be reused to make additional copies after it is erased and cleaned.

In the following, preferred embodiments of the invention are explained in more detail with reference to the accompanying drawing:

Figure 1 shows in a schematic partial cross-sectional view an embodiment of the light receiving device according to the invention in layered construction.

Figures 2A to 2C show the related mapping steps.

As shown in Figure 1, the light receiving device comprises 10 a substrate layer 12 covered with a hole injection layer 14 is coated from trigonal selenium or gold, which in turn is coated with a transport layer 16, which consists of a selenium-arsenic alloy doped with a halogen, as indicated below, this layer in turn with a charge generating layer 18 made of an inorganic photoconductive material such as one Selenium-tellurium alloy is coated with an optional hole trapping layer 19 and finally a coating layer 20 made of an insulating organic synthetic resin, for example of polyurethane or polyester are provided.

The substrate layer 12 may and may comprise any suitable material having the required mechanical properties for example from a layer of an organic or inorganic Material with a conductive one on it

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Surface layer or made of conductive materials such as Aluminum, nickel or similar materials are made. A main purpose of the substrate is to serve as a support and systems can be imagined / in which the substrate can be completely absent. The thickness of the substrate layer, which in some Cases an optional shift may be depends on many factors including economic considerations, and the design of the device in which the light responsive device is to be used. This layer can therefore have a considerable thickness of, for example, up to 508 χ 10 cm or a minimum thickness that is at about 12.7 χ 10 "cm, provided that there are no detrimental effects Influences on the system arise. In general, the

_3 Thickness of this layer, however, in the range of about 12.7 χ 10 to

_3
about 254 χ 10 cm. The substrate can be flexible or rigid and can be in a variety of different shapes, for example in the form of a plate, a cylindrical drum, a spiral, an endless flexible belt, or the like.

The hole injection layer 14, which is made of trigonal selenium or gold, injects charge carriers or holes into the layer 16 under the influence of an electric field. The injected Charge carriers should have the same polarity as the mobile carriers passed through the transport layer, namely layer 16, be transported during the imaging process. The thickness of the layer of trigonal selenium is in the range of about 0.5 μm to about 10 μm, preferably from about 1 μm to about 5 μm, while the thickness of the injection layer made of gold is in the range from about 0.02 μm to 10 μm. The greatest and the smallest strength this layer are generally determined by the desired electrical properties and not a specific one Limited strength. The charge carrier or hole injection layer and the charge carrier transport layer likewise require one certain work function relationship, thus a hole injection

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can be carried out efficiently from the former to the latter, while an injection of charge carriers with opposite signs is kept as low as possible.

The transport layer 16 consists of one doped with a halogen Selenium-arsenic alloy, the percentage of selenium being in the range from about 99.5% to about 99.9%, while the percentage of arsenic ranges from 0.1% to about 0.5%. The amount of halogen, for example chlorine, fluorine, Iodine or bromine is in the range from about 10 ppm to about 200 ppm, preferably in the range from about 50 ppm. up to about 100 ppm. A the preferred halogen is chlorine. While other alloys have a cyclic residual potential of 200 volts or more after 1000 copy cycles in an electrophotographic system, the alloy according to the invention thus has residual potentials of Zero to 25 volts after the same number of copy cycles. The thickness of this layer is generally in the range of about 5 to about 60 µm, preferably from about 25 to about 50 µm. Other inorganic photoconductors can be used for this layer, for example amorphous selenium, various other selenium alloys including selenium-tellurium, arsenic-sulfur-selenium and with various Halogen materials doped selenium and other suitable panchromatic inorganic substances can be used.

In one embodiment, the inorganic photoconductive and charge-generating layer 18 consists of a selenium-tellurium alloy with a percentage of selenium between about 70 to about 90% and a percentage of tellurium between about 10 to about 30%. Preferably, about 75% selenium and 25% tellurium are in the charge generating layer 18. The strenght this layer ranges from about 0.1 µm to about 5 µm, preferably from 0.2 to 1 µm. The charge generating layer generally has a thickness sufficient to be at least 90% or more of the incident radiation to absorb that on

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this layer falls during the imagewise exposure.

The electrically insulating coating layer 20 generally has a thickness of about 5 to about 25 μm, preferably of about 12 to about 18 μm. This layer generally has a protective function in that it protects the surface of the photoconductive material from contact with the toner and the ozone generated during the imaging cycles is generated, and protected from physical damage by scratches or the like. The coating layer also prevents corona charges from penetrating through the layer into the charge generating layer 18 and from the the latter can be injected into this layer. Preferably, therefore, the layer 20 consists of a material that has a high Has carrier injection resistance and low carrier mobility. The smallest strength of this The layer is determined by the function that the layer has to fulfill, whereas the greatest strength is determined by mechanical considerations and determining the resolving power that the photo-responsive device is to exhibit. Typical suitable plating materials are polyethylene, polycarbonate, polystyrene, polyester, Polyurethane and similar materials, including the polyurethane available from Mobil Corporation or Kansai Paint Company and polyester available from Goodyear Chemical Company are preferred materials of the coating layer.

The formation of the insulating layer over the charge generating layer can be carried out by one of the many known methods, for example be carried out by spraying, dipping, roller painting or the like, a solution of a layer material being applied will. Evaporation of the solvent leaves a hard, tough layer. Procedures can also be used not working with a solution.

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In the following, the operation of an embodiment of the element according to the invention will be described with reference to FIGS. 2A to 2C described. In this representation, the initial charging takes place with negative polarity. As stated above however, the method is not limited to this embodiment. In addition, the procedure is related with a proposed theoretical mechanism which is believed to drive the process is able to work to understand the inventive training. It should be noted, however, that this procedure has proven to be workable and highly efficient over actually performed Experiments have shown and any inaccuracy in the proposed theoretical working mechanism is not considered a restriction is to be considered.

In Figure 2A, the light receiver is in a state after the first negative electrical charge evenly over its surface in the absence of lighting by means of a suitable one electrostatic charging device, such as a corotron shown. The negative charges sit on the Surface of the electrical insulating layer 20. As a result of the charge, an electrical field forms over the light em— recipient and as a consequence of the electric field and the work function relationship between the layers 14 and 16 holes from the charge carrier injecting layer into the Charge carrier transport layer injected. Those in the charge carrier transport layer injected holes are transported through the layer, enter the one that generates the charge carriers Layer 18 and hike through this layer until you reach the Interface between the charge carrier generating layer and the electrically insulating layer 20 reach where they are trapped will. The charges trapped in this way at the interface form an -electric field over the electric

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insulating layer 20. It can thus be seen that at an embodiment in which a negative charging takes place in the first charging step, the charge carrier injection layer 14 and the charge carrier transport layer 16 must comprise materials that allow injection of holes from allow the former layer into the latter and allow that the holes reach the interface between the layer 18 and the electrically insulating layer 20.

Then the element is again without lighting a second time charged with a polarity opposite to the polarity used for the first charge, to essentially neutralize the charges that sit on the surface of the element. In the present embodiment the second charging of the element takes place with positive polarity. After the second charge, the surface should of the light receiver must be essentially free of electrical charges. The essentially neutralized surface is caused in that a charging voltage is selected in such a way is that a number of positive charges are applied, which is equal to the number of previously applied negative Charges is. The essentially neutralized state is to be understood as meaning that the voltage across the light receiver is essentially zero.

FIG. 2B shows the state of the light receiver after the second charge. In this illustration there are no charges on the Surface of the element shown. The positive charges that appear at the interface of layers 18 and 20 as a result of the first Charge remain trapped at the interface at the end of the second charge. There is therefore now a uniform Layer of negative charges, which are located at the boundary layers 14 and 16 is located.

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The result of the second charge is therefore / that a uniform electric field over the charge carrier transport layer and the charge carrier generating layer is formed. In order to obtain this result, it is of particular importance that the negative charges are attached to the Interface between the charge carrier injecting layer 14 and the charge carrier transport layer 16 are located and thereon prevented from entering the transport layer and being transported through the transport layer. For this reason it is imperative to use a material for the charge carrier transport layer to use an injection of only one type of charge carrier, namely the holes, in the present case Embodiment allowed. This is particularly necessary when a charge carrier transport material is used that can transport both types of load carriers.

As shown in FIG. 2C, the element is then electromagnetic with a pattern corresponding to the image Radiation is exposed to which the material generating the charge carriers, which forms the layer 18, is responsive. The exposure of the element can be carried out through the electrically insulating coating. As a result of the corresponding to the picture Exposure, a latent electrostatic image is formed in the light receiver. The reason for this is that hole-Blektron pairs are generated in the areas of the layer generating the charge carriers that are struck by the light. The through the Light generated holes are injected into the charge carrier transport layer and migrate through this layer to being neutralized by the negative charges present at the interface between layers 14 and 16. The electrons generated by the light neutralize the positive charges that exist at the interface between the layers 18 and 20 are captured. In the areas of the element that

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receive no light, the positive charges remain in theirs original location. In the areas that do not receive any light, an electric field therefore remains above the charge carrier transport layer and the layer generating the charge carriers, whereas the electric field across the same layers is applied to the Areas receiving light are discharged, i.e. degraded, to a certain low level, as shown in Figure 2C is.

The latent electrostatic image formed in the element can be used for Formation of a visible image by any known xerographic development process, for example by a cascade process, a magnetic brush method, a liquid development method, or the like was developed will. The visible image is typically transferred to a receiving element by means of a conventional transfer technique and fixed there. Although the electrostatic latent image is preferably developed with a marking material, the image can also be used in other ways, for example read with an electrostatic scanner.

When the light receiving device according to the invention for manufacturing additional copies are to be reused, as is the case with a rotating xerographic device, must have any residual charge on the light receiver after the transfer of the visible image on a receiving element remains, typically before each repetition of the copy cycle as well how any residual toner material can be disposed of after the image is transferred. In general, the remaining charge can come from the light receiver be removed by ionizing the air over the electrically insulating coating of the light receiver, while the photoconductive charge generating layer is uniformly illuminated and grounded. For example, the charges be removed from a light source via an alternating voltage corona discharge in the presence of illumination, wherein

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preferably a grounded conductive brush in contact with the surface of the light receiver in the presence of such Lighting is brought. The last procedure will also remove residual toner particles that are on the surface of the light receiver ' are left over.

Optionally, in the device according to the invention, a separate layer, i.e. a hole trapping layer, can be provided between the charge carrier generating layer and the Coating layer is and consists of the same materials as was described with respect to the hole transport layer. These Hole trapping layer and the hole transport layer can be substantially similar or different in composition. The hole-trapping layer can thus consist of a selenium-arsenic alloy doped with a halogen, the percentage The proportion by weight of selenium is from about 95% to about 99.9% and preferably from about 99% to about 99.9%, the percentage by weight of selenium being from about 0.1% to about 5% and is preferably 0.1 to 1%. The amount of halogen material is from about 10 ppm to about 200 ppm, and preferably 20 ppm. up to 100 ppm. The hole-trapping layer can also be made of selenium, arsenic-sulfur-selenium alloys, organic materials such as aromatic amines and similar materials.

The thickness of the hole trapping layer is in the range from about Ο, ΟΙμπι to about 5μπι, preferably from about 0.01μΐη to about 1μπι. The minimum thickness of the hole trapping layer can be smaller or larger, but the hole trapping layer must be sufficient Have strength to provide sufficient capture of the holes at the coating interface. The maximum strength is determined by the level of light absorption in the trapping layer. In the ideal case it is desirable that essentially all of the light be in the highly sensitive charge carrier

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generating layer of Se-Te is absorbed. Trapping layers made of selenium alloys, for example, absorb a lot of light, where the level of absorption depends on the thickness of the layer and the wavelength of the light. The light generation more mobile Carrier (holes) takes place less effectively in the trapping layer than in the layer generating the charge carriers, so that the Sensitivity is lower. It is therefore desirable to provide a capture layer that is as thin as possible for as long as possible the thickness of the layer is compatible with effective trapping of the injected holes coming from the back of the structure is.

The hole trapping layer that is between the charge carrier generating Layer and the insulating coating layer is important, because when the holes, i.e. the positive charges, not be adhered to the interface between the above two mentioned layers significantly, the effectiveness of the Light receiving device is adversely affected if such holes freely return to the charge carrier generating Layer can hike. If some holes can migrate, they will migrate to the electrode layer and the negative charges neutralize that lie between the hole injection layer and the transport layer, which lowers the overall voltage, which can be used for the subsequent imaging process. This would adversely affect the imaging system and at the same time reduce the effectiveness of the device and the cyclical properties of such a device make unstable. It is important to note that the device will operate without a capture layer, however depending on the extent and frequency of the migration of the holes through the system the amount of holes that appear at the interface is held between the charge carrier generating layer and the insulating layer changes, resulting in a cyclical instability. The light-responsive

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direction can remain photosensitive without a capture layer, but higher initial fields are required to achieve the To make the device effective, and the disadvantage of using higher fields is that they can break through the System ^ and more ozone is generated, so that in some situations environmental problems arise. Preferably be lower voltages are used, which is more effective and stable, and the dark decay continues with a hole-trapping layer of the system, i.e. the charge loss is significantly better, so that the dark decay is essentially reduced is.

The capture layer can be formed by a variety of methods. One method uses a separate trough in a vacuum coating facility containing a small amount of a selenium-arsenic alloy, the weight of that amount of alloy having been previously calibrated and calculated to give the desired thickness of the capture layer. Subsequent to the formation of the charge carrier generating layer, the alloy material is evaporated using a specific prescribed time temperature program. A typical program comprises an evaporation over 5 minutes, during which time the temperature of the Tigels of 80 ⁰ C to 415 ° C increases.

In another embodiment, the following method is used to form the capture layer. Following the formation of the injection layer is a Tigel from which the selenium and gold was completely evaporated to form the injecting layer, partially allowed to cool and maintained at a constant soak temperature of typically 80 ⁰ C. This temperature is low enough to allow a small amount of steam for the transport layer that will subsequently pass

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the formation of the transport layer was formed, is deposited on the trough for the injection layer. Following the formation of the charge generating layer, the temperature of the boat, to which a small amount of the material of the transport layer is fused, increased from about 80 ⁰ C to about 415 ° C in about 4 minutes, so that, evaporates the condensate again . The re-evaporated material is deposited on top of the charge generation layer to form the trapping layer.

In the following the invention is illustrated by means of specific exemplary embodiments described, it being pointed out that the invention does not apply to the materials given in the examples, Conditions, process parameters and the like is limited. All parts and percentages are parts by weight, if there is not stated otherwise.

Example I.

A photoresponsive device has been formed by sequentially laying on a plurality of discrete inorganic layers a 12.7 χ 10 cm thick sanded and etched aluminum substrate in a standard vacuum coating device

—4

an underground pressure of 1 to 2x10 Torr, i.e. mmHg.

The aluminum substrate was first heated to between 110 and 119 ° C. While the substrate was kept in this temperature range, high-purity selenium was deposited by a Edelstahlschiffchen from the substrate whose temperature was raised over a period of 13 minutes from about 25 to 33O ⁰ C. Upon contact with the heated substrate, the condensing selenium vapor immediately forms a layer of trigonal selenium with a thickness of about 3μπι. The substrate temperature was then reduced to 65 to 80 ^° C. in preparation for the subsequent vapor deposition.

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The transport layer was then formed by depositing a selenium-arsenic alloy with a composition of 0/33% arsenic, 20 ppm chlorine and 99.6% selenium in a thickness of 60 μm onto the layer of trigonal selenium. During this step, the substrate temperature was maintained at 65 to 70 ⁰ C, the temperature of the Tigels was increased with the alloy of about 25 to about 290 ⁰ C and the deposition was completed in 27 minutes.

At a substrate temperature in the range from 6 to 67 ^° C., the layer generating the charge carriers was then deposited on top of the transport layer. Pressed pellets of a powdered selenium-tellurium alloy with 75% selenium, and 25% of tellurium were evaporated over a period of 11 minutes from a Tigel whose temperature was raised from 190 to 405 ⁰ C. The result was a layer of a selenium-tellurium alloy with a thickness of 0.3μΐη. The three-layer structure described above was then coated with an 18 μm thick layer of Vitel, ie a polyester resin available from Goodyear Chemical Company, using a conventional solution spray method.

Example II "7 *

A photoresponsive device was made in essentially the same manner as in Example I with the exception that that a cylindrical aluminum tube with a diameter of approximately 11.7 cm and a length of 40.6 cm as the substrate was used, the material of the transport layer being an alloy of 0.12% arsenic, 87ppm chlorine and 99.9% selenium was, the charge carrier generating layer had a thickness of 0.6μΐη and the coating layer instead of polyester a polyurethane material.

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Example III

The procedure of Example I was repeated with the exception that the transport layer consisted of 0.5% arsenic, 99.5% selenium and 20ppm chlorine.

Example IV

The procedure of Example II was repeated except that the transport layer was 0.2% arsenic, 99.8% selenium and 100 ppm chlorine.

Example V

The procedure of Example II was repeated except that the transport layer was 0.33% arsenic, 99.6% selenium and 100 ppm chlorine.

Example VI

The procedure of Example II was repeated except that the transport layer was 0.4% arsenic, 99.6% selenium and 200ppm chlorine.

Example VII

The procedure of Example I was repeated with the exception that the charge carrier generating layer was composed of a Selenium-tellurium alloy, which contained 80% selenium and 20% tellurium, the thickness of the layer Ο, βμΐη was.

When the photoresponsive devices of Examples I, II, III, IV, V, VI and VII were used, using an imaging method with double charging images in the above illustrated with reference to FIGS. 2A to 2C

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Way to form, then resulted in images of good quality and high resolution, which were comparable to images, those with conventional light receivers using known xerographic imaging methods with a single Charge are formed. The comparisons are based on optical tests.

Example VIII

A 0.051 cm diameter gold wire obtained from Engelhard Industries, Cartered, New Jersey, was cut into pieces 1.3 to 2.5 cm in length and placed from a molybdenum gel onto an aluminum substrate in one Thickness of 381 χ 10 cm at room temperature and a pressure of

-4
10 mmHg evaporated. The resulting gold film had a thickness of 0.1 μm and was then treated with a glow discharge plasma at a pressure of 50 μmHg and at the same time heated to 45 ° C. Then a 60μπι thick film of a selenium-arsenic alloy doped with a halogen (99.6% selenium, 0.33% arsenic, 20ppm chlorine) was applied to the gold layer

-4
vapor-deposited at 60 ^° C. and 10 mmHg, this layer serving both as a transport layer and as a layer generating charge carriers.

The above procedure provides an inorganic photoresponsive Layered device made of an aluminum substrate coated with a gold injection layer which in turn with a combined charge transport and charge generation layer is coated with a halogen-doped arsenic-selenium alloy.

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Example IX

A layered inorganic photoresponsive device was formed in the same way as in Example VIII except that on the layer of a doped with a halogen Selenium-arsenic alloy has a separate layer, i.e. a layer generating charge carriers with a thickness of 0 / 3μπι was applied, which was made of an alloy of 75 percent by weight Selenium, 21 percent by weight tellurium, and 4 percent by weight arsenic, resulting in a photoresponsive device led in layered construction.

Example X

The procedure of Example IX was repeated with the exception that the charge carrier generating layer was coated with a hole trapping layer having a thickness of 0.1 μm and consisted of a selenium-arsenic alloy containing 98% selenium and contained 2% arsenic.

Example XI

The photoresponsive devices made in Examples VIII and IX were stored at room temperature covered with an organic polyurethane coating using a spray gun, which had a thickness of 12μπι.

When these coated light receiving devices in an imaging system with double charging, i.e. with a charging with uniform negative charges and a subsequent one When charging with an equal number of positive charges were used, the images were of high quality and excellent Resolution.

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Example XII

The photoresponsive ones made in Examples VIII and IX Devices were made with photoresponsive devices with injection layers of different materials compared, showing the following results:

Material hole injection efficiency

Gold 100%

Copper 14%

Cadmium 10%

Zinc 13%

Chromium 12%

Example XIII

A photoresponsive device was made in essentially the same manner as Example I with the addition, that a capture layer with a thickness of 0.1μπι on top of the charge carrier generating layer "made of selenium-tellurium was trained. The capture layer was formed by adding a weighed amount of an alloy of 0.33% arsenic, 20 ppm Chlorine and 99.6% selenium was evaporated from a heated vessel in a separate vapor deposition step.

The trigonal selenium injection layer was made by vapor deposition formed by selenium from a heated crucible as in Example I. This dice, from which the selenium had been vaporized, became Filled with an amount of the above alloy, which was calculated so that a precipitate with a thickness of 0.1μπι resulted. In addition, two other symbols were added as in the case of

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Game I related, one of which contained the material for the transport layer and the other the material for the layer generating the charge carriers, the materials of this tig having been vapor-deposited as in Example I. Subsequently, the temperature of the Tigels containing the material for the Locheinfangsschicht was increased from about 175 ° C to about 340 ⁰ C and was vapor deposition over a period of 3 minutes. The finished device, built up from four layers and comprising a hole injection layer which is coated with a transport layer, which in turn is coated with a charge carrier-generating layer on which a hole-trapping layer is finally located, was coated with a polyester resin (Vitel) in a thickness of 15μπι coated.

Example XIV

A photoresponsive device was fabricated in substantially the same manner as in Example II except that the hole trapping layer was formed over the charge generation layer by a vapor deposition technique. During the vapor deposition of the transport layer and the layer generating the charge carriers, the dome with the trigonal selenium, from which the material of the injection layer was vapor-deposited, was left at the ambient temperature, namely at the temperature of the coating device. During this time the temperature increased from approximately 35 ° C to about 80 ⁰ C to, with a small amount of the material of the transport layer, which was reflected thereon was used to form the injecting layer. In contrast to Example II this empty Tigel was maintained at about 25O ⁰ C during deposition of the transport layer and the charge carrier generating layer, so that no material condensed thereon.

After the precipitation of the charge carrier generating layer, the temperature was the above-mentioned Tigels of 80 ⁰ C to about

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415 ° C increases / thereby the small amount of precipitated Vaporize hole trapping material and condense on top of the charge carrier generating layer, creating the topmost coating in the form of the hole trapping layer with a thickness of Ο, ΟΙμπι was formed.

When the photoresponsive devices of Examples XIII and XIV were used to create images using an image s procedure with dual charging that in the previous one has been described in detail with reference to FIGS. 2A to 2C, images of good quality with high resolution resulted were comparable to images obtained with conventional light receivers using known xerographic imaging techniques can be formed on a single charge. The comparisons are based on optical observations.

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Claims (8)

A.jBRÜNECKER DW - INO H. KINKELDEY W. STOCKMAIR CW-IMG -AaE (CMJKH K. SCHUMANN ORKKHAT [> Pl_-PHVS PH JAKOB DtPL-ING. G. BEZOLD cn new Nat> cin_-oeM 8 MUNICH 22 MAXIMILIANSTRASSE 43 P 15 993-40 / Da March 4, 1981 Xerox Corporation Xerox Square Rochester, New York 14644 Layered light responsive device and electrophotographic imaging using such a prior art device 1. A layered construction that responds to light, characterized by a) a substrate (12), b) a layer (14) of a hole injection material which inject holes into a layer on its surface can, the layer (14) of trigonal selenium or Gold is made c) a hole transport layer (16) in working contact with the Hole injection layer (14), the hole transport layer (16) consisting of a selenium-arsenic alloy doped with a halogen, whose percentage by weight of selenium is 99.5% to 99.9%, whose percentage by weight of arsenic is 0.1% to 0.5% 130062/0679 TKLBFON (OtO) <J2 αβ 60 TCLBX Οβ-Οββ · Ο TIII9WMME MONAPAT TELEKOPIEREF » and their halogen content is 10 ppm to 200 ppm, d) a charge generation layer (18) overlying the hole transport layer (16) and consists of a selenium and tellurium alloy, the charge-generating layer (18) has a thickness in the range from 0.1 μΐη to 5 μΐη and e) a layer (20) made of an electrically insulating organic Resin material overlying the charge generation layer (18). 2. Apparatus according to claim 1, characterized in that the hole injection layer (14) made of trigonal Selenium consists in that the substrate (12) is conductive and that the insulating coating layer (20) made of an organic resin material consists of a polyester or polyurethane material. 3. Apparatus according to claim 1 and 2, characterized in that the substrate (12) consists of aluminum, that the hole transport layer (16) consists of selenium-arsenic 99/9% selenium, 0.1% arsenic and 50 to 100 ppm of a halogen material and that the insulating coating layer (20) consists of an organic Resin consists of a polyester resin. 4. Apparatus according to claim 1, characterized in that the thickness of the substrate ^{layer (12) in the range of 12.7 χ 10 -3} to 508 χ 10 "" ³ cm, that the thickness of the layer (14) from the hole injection material in the The range is from 0.5μπι to 10μΐη and that the insulating coating layer (20) made of an organic resin material has a thickness of 5μπι to 25μπι. 5. Electrophotographic imaging process using a light responsive device according to claim 1, characterized in that the light responsive Device with negative electrostatic charges is charged, that the device is then charged with positive 130052/0678 - 3 - ■■ 3108158 Electrostatic charges are essentially the negative charges sitting on the surface of the device to neutralize, and that the device with a pictorial Pattern of electromagnetic radiation is exposed to which the material generating the charge carriers responds, whereby an electrostatic latent image is formed on the photoresponsive device, and optionally the latent electrostatic image is transferred to a permanent support after its development. 6. The method according to claim 5, characterized in that that the charge injection layer consists of trigonal selenium, that the substrate is conductive, that the transport layer of selenium-arsenic comprises 99.9% selenium, 0.1% arsenic and 50 to 100 ppm of a halogen material, and that the insulating coating layer made of an organic resin made of a polyester or polyurethane material consists. 7. The method according to claim 5, characterized in that that the thickness of the substrate layer is in the range of 12.7 up to 254 χ 10 cm that the thickness of the layer of the hole injection material in the range from 0.5 to 10μΐη that the thickness of the hole transport layer in the range from 5μΐη to 60μΐπ that the thickness of the charge generation layer is in the range of 0.1 µm to 5 µm and that the insulating coating layer from an organic resin material has a thickness of 5μπι to 25μιη. 130052/0678