DE2447455A1 - METHOD FOR CONDITIONING SELENIUM PHOTORECEPTORS - Google Patents

Description

25 993 Wt / My

Xerox Corporation, Rochester, N.Y. 14603 / USA

Process for conditioning selenium photoreceptors

The invention relates to a method for conditioning electrophotographic imaging materials wherein the photoconductive Image layer contains amorphous selenium or selenium alloys. According to the method according to the invention, the photoconductive imaging layer treated with a liquid containing at least one N-substituted morpholine compound the formula

, 0

■ N '

R.
contains where

R represents a saturated aliphatic hydrocarbon group having from about 8 to about 30 carbon atoms.

The application of such materials to the image layer of the image materials provides that layer with a paint or a finish that is capable of removing the layer before

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rubbed and to protect the adverse effects of moisture, while at the same time the charge absorption is improved and thus the solid occupancy or density development is improved.

The invention relates to a method, an image material which is produced according to this method, and the use of the imaging material in imaging processes. The invention particularly relates to methods for preconditioning and Reconditioning of imaging layers of an electrophotographic imaging material, the overcoated electrophotographic Imaging material obtained in this treatment and an imaging method in which such overcoated electrophotographic imaging material is used.

The formation and development of images on an image layer made of photoconductive materials by electrostatic means Action is well known. In the best known technical processes, which are usually also called xerography are known, an electrostatic latent image is formed on the imaging layer of an imaging material by you first uniformly electrostatically charge the surface of the image layer in the dark and then this exposing an electrostatically charged surface to a light and shadow image. The areas of the image layer hit by light then become conductive and the electrostatic charge is selectively consumed in these exposed areas, After the photoconductor has been exposed, the electrostatic latent image on this surface becomes the image contains, made visible by touching a finely divided, colored, electroscopic powder material that is on this area known as "toner" was developed. This toner is mainly from those areas of the image bearing Surface that retains the electrostatic charge.

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hold, and thus a visible powder image is formed. ·

The developed image can then be read off or permanently on the photoconductor are fixed in the case when the imaging layer is not reused. This latter "method is generally used for binder-like, photoconductive films where the photoconductive layer is an integral part of the final copy.

In the so-called "plain paper copying systems", the latent image on the imaging surface of a reusable Photoconductor can be developed or transferred to another surface such as a sheet of paper and then transferred be developed. When the latent image is on the imaging surface A reusable photoconductor is developed, it is then transferred to another substrate and then permanently fixed on it. Any of a variety of known methods can be used to create the toner image to the transfer sheet permanently, including overcoating with transparent films and solvent or thermal fusion of the toner particles to the carrier substrate.

Before recycling the photoreceptor, any untransferred toner particles must remain on the surface of the image layer of the photoreceptor are removed to reduce the quality of subsequent copies to prevent. Various devices have been used in the past to remove this toner residue from the surface of the photoreceptor. Typical such cleaning methods are rotating brushes, as shown in the U.S. Patent No. 2,832,977, cleaning nets of the type described in U.S. Patent No. 3,186,833, and cleaning devices having wings or leaves of the type described in US Pat. No. 3,634,077. The relative

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The performance with which these cleaning devices remove toner residues often depends on a number of variables including the presence of an additive in the developing composition, the presence of a coating on the photoreceptor surface, the relative electrostatic attraction of the toner to the photoreceptor surface, and the physical force that occurs acts against the photoreceptor surface from the cleaning devices. Since the imaging surface of selenium photoreceptors is sensitive to abrasion, pressure contact between the above cleaning devices and this surface must be kept to a minimum in order to prevent damage to the imaging surface. This frictional contact of the cleaning devices against the photoreceptor surface can also result in erosion of the cleaning materials, see US Pat. No. 3,682,689. The winged cleaning device, as mentioned above, is particularly sensitive to this type of abrasion. If the photoreceptor surface is somewhat irregular, especially if it contains fine projections, the pressure contact of the leading edge of the cleaning device wing against that surface can result in rapid destruction of the cleaning sheet or wing. To minimize the possibility of this occurrence, particular care must be taken in the manufacture of photoreceptors. Such caution must be exercised at all stages of the manufacture of this multi-layer component, as any imperfections in the underlying layers can translate into irregularities on the surface of the outer layer of photoconductive materials.

During operation of photoreceptors heavily loaded with toner it is common practice to polish the surface of the photoreceptor with an abrasive to remove accumulated Remove toner residue and restore the photoreceptor surface to its original state. Such

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Abrasives are also used in the reconditioning of such photoreceptor surfaces to low levels Scratches that are formed during prolonged use have to remove. The same abrasives are used today in the manufacture of new photoreceptors to be sure of any errors or irregularities (especially small projections) before installing of the photoreceptor can be removed to a copier where the winged cleaning device is inserted. Unfortunately contains a number of commercially available abrasives that are used for preconditioning and reconditioning used by selenium photoreceptors, also residues on the imaging surface of the photoreceptor adhere, and thereby the electrophotographic properties worsened. One type of residue that has proven particularly difficult is glycerol monostearate. The extent to which this compound interferes with the electrophotographic properties of the photoreceptor will vary with the particular composition of the imaging layer of the photoreceptor. For example, when the photoconductive insulating material contains an arsenic-selenium alloy, the effects of this compound on the photoreceptor are particularly strong pronounced.

The present invention is therefore based on the object to provide a method of eliminating the adverse effects of the above and similar residues on photoconductive insulating layers, containing amorphous selenium or selenium alloys to a minimum.

The invention is "in particular the object of a Process to create new electrophotographic imaging materials to precondition, wherein the photosensitive layer contains amorphous selenium or selenium alloys.

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Another object on which the present invention is based, is to create a method to be used, electrophotographic To recondition imaging materials in which the photosensitive layer is amorphous selenium or selenium alloys contains.

Another object of the present invention is to provide the imaging surface of the imaging materials with a coating to provide during preconditioning, which improves both abrasion and moisture resistance v / earth and additionally the solid density development (solid density development) is strengthened.

Another object of the present invention is to provide the imaging surface of the imaging material with a coating to be provided during reconditioning, which improves both abrasion and moisture resistance and additionally the solid density development is increased.

The present invention is also based on the object of creating an overcoated imaging material, wherein the coating or top coat provides improved abrasion and moisture resistance in addition to one improved, fixed density development.

Finally, another object of the present invention is to provide an electrophotographic imaging method which in which the above-coated imaging materials are used.

The invention relates to a method for conditioning photoconductive layers, the amorphous selenium or selenium alloys contain an electrophotographic imaging material or part. The method according to the invention is there-

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characterized in that an imaging material having a photoconductive imaging layer thereon which is amorphous Contains selenium or a selenium alloy, with one when conditioning effective amount of at least one N-substituted morpholine compound of the formula

.0

CJ

is treated in which

R represents a saturated aliphatic hydrocarbon group having from about 8 to about 30 carbon atoms.

In preferred embodiments of the present invention, a dilute solution of one or more of the above is used Compounds applied to the image layer of the photoreceptor containing amorphous selenium or selenium alloys, and after a predetermined time, the excess solution is removed. The preferred connection used with this Method used is N-lauryl morpholine.

Description of preferred embodiments

The electrophotographic imaging material which can be treated according to the invention contains a conductive substrate, which is coated on at least part of its surface with a photoconductive film, the amorphous selenium, contains a selenium alloy or mixtures thereof. Any of the conductive substrates that are commonly found on The manufacture of electrophotographic imaging materials can be used for the manufacture of the overcoated electrophotographic imaging materials according to the invention. Such substrates can be flexible or inflexible, organic or inorganic and transparent or opaque be. Examples of substrates that can suitably be used in such devices include aluminum,

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Nickel, chromium, polyethylene terephthalate coated with a thin metal film, or metallized plastic films. Usually, before the deposition, the photoconductive Insulating layer deposited on such a substrate, a boundary separating layer on such a substrate to a blocking contact or blocking contact against premature injection of carriers from the conductive substrate in the photoconductive insulating layer to prevent. This interface barrier may be an insulating material such as a dielectric An inorganic oxide film. It is generally preferred that such boundary barrier layers be capable are to enable rectification. After the conductive substrate is made and an interface barrier has been formed thereon (if desired), the substrate is placed in a vacuum evaporation chamber and the photoconductive An insulating layer of selenium, selenium alloy or mixtures thereof is deposited on the appropriate surface of the substrate. The deposition of such photoconductive materials can proceed until the deposition is substantially one forms a uniform film having a thickness ranging from about 0.1 to about 100 microns.

During the evaporation of such conductive materials Tiny dust particles can build up in the vacuum evaporation comb along with the selenium on the deposit conductive substrate and so in the photoconductive Plating error or /. Form spots. To eliminate the effect of such bumps, the photoconductive is used Surface lightly polished with an abrasive until these defects are completely removed. As previously stated, can organic residues contained in these agents on the image surface of the photoconductive insulating layer adhere, and if not removed, the electrophotographic properties of the imaging layer are impaired worsened.

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In order to eliminate such residue effects and to improve the abrasion resistance, moisture resistance and / or charge acceptance, a solution containing one or more of the compounds described above is applied to the imaging layer of the photoreceptor in sufficient amount to result in one or more of the above improvements. A typical solution of such a conditioning agent should contain sufficient conditioning compound to give the beneficial results desired while still facilitating processing of the photoreceptor. For example, if 1 g of the conditioning compound is dissolved in approximately 100 ml of a suitable solvent, the required residence time of the conditioning solution on the imaging material to give the desired beneficial results is quite considerable, generally longer than 20 minutes. When the concentration of conditioning compound in the appropriate solvent is from about 5 to about 10 grams per 100 ml of solvent, the residence time of the solution on the imaging layer need only be about 5 minutes to obtain the desired inexpensive top coat or finish. If the concentration of conditioning compound is significantly above 10 g / 100 ml of solvent, the increased viscosity of the conditioning solution causes difficulties in the uniform application and penetration of the conditioning compounds into the microporous surface of the image layer. Solvent _t which are suitable as carriers for the distribution of the conditioning agent on the imaging layer must be equipped with the imaging layer be compatible (they must not interfere with the electronic and / or physical properties or change), and they must also with the environment where the conditioning takes place , be compatible. Examples of solvents suitable for making conditioning solutions include methanol, ethanol, n-propanol, isopropanol, and n-butanol.

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After the preparation of the conditioning solution, it can be applied to the image layer of the image material according to any known method Apply standard coating procedures including aerosol or wipe application. which The way in which the conditioning solution is applied to the image layer is also ultimately used, it must be uniform Covering the surface of the imaging layer with sufficient conditioning compound results in the residues, if any, of organic abrasives being effective remove, improve abrasion resistance, moisture resistance to improve and / or the charge acceptance, to improve. In order to enhance one or more of these properties it is not absolutely necessary to that all properties are enhanced in these treatments. For example, if the conditioning compound is one relatively small aliphatic hydrocarbon substituents (8 carbon atoms) contains relative abrasion resistance the imaging layer is not improved to the extent that it would be improved if this substituent were more than about Contains 20 carbon atoms. The cargo acceptability however, it is greatly improved when the imaging layer is conditioned with compounds that are relatively short chain carbon Subs tituents included.

After applying the conditioning solution over substantially the entire imaging layer of the electrophotographic imaging material the solution can leave the surface of the imaging layer for a time of about 3 to 10 minutes Saturate (preferably about 5 minutes). After the photoreceptor is saturated, non-adsorbed conditioning materials become removed from the surface by wiping the surface with a damp, soft material or sponge. The wiping material used to remove excess conditioning agent is usually with the the same solvent carrier moistened, which in the

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Turning the conditioning compounds onto the image layer was used. After removing the excess conditioning compounds, the imaging surface is covered with a soft, absorbent fabric or other suitable means dried. It is generally preferred that the solvents used to disperse and remove the conditioning compounds are used by the surface of the photoreceptor, are very volatile and thus evaporate from the surface without leaving any traces on the surface.

Conditioning the drum in the manner described above does not change the appearance of the imaging layer, as does the conditioning compound is present in very small quantities and cannot easily be determined, with the exception of the well-analytically elaborated procedures. For example, when an electrophotographic imaging material has a Conditioned the image layer on the surface area corresponding to approximately 3000 cm in the manner described above becomes ,, then the amount of conditioning compound, extractable from the layer, about 0.6 to about 1.5 mg or about 0.2 to about 0.5 / Ug / cm.

The presence of the conditioning compound on the imaging layer can be determined by infrared spectroscopy after 4000 copies to be established. For a typical assessment of performance effectiveness of the conditioning process is an electrophotographic imaging material prepared according to the invention The ancestor is conditioned, placed in an electrostatographic copier, and the copies are grounded Checked up to 10 QOO copies (2 copies per cycle of the photoreceptor). The cleaning device of this copier contains a polyurethane wing that translates or moves laterally along the surface of the photoreceptor. The developing composition used in this copying

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device used contains a non-lubricating one Additive designed to enhance the removal of residual toner from the surface of the photoreceptor. A comparison the effectiveness of cleaning both before and after conditioning the imaging layer of the photoreceptor shows an approximately 70% reduction in the frictional forces between the leaf or wing and the image layer. A comparison of the charge absorption of the conditioned and unconditioned Part of the photoreceptor shows about 10 years Increase in charge acceptance in the conditioned areas.

This treatment of photoreceptors with selenium or selenium alloys enables the surface of the photoreceptor to be given a top coat which extends its useful life and, in addition, reduces maintenance requirements the photoreceptor and the cleaning devices which are used to remove residual toner from the image layer of the photoreceptor are reduced.

The following examples illustrate the invention without restricting it. The devices or equipment and methods used in these examples, are as previously stated, standard devices or procedures _0. All parts and percentages are expressed by weight unless otherwise specified.

Example 1

An electrophotographic imaging material with an imaging layer that contains an alloy of arsenic and selenium (65 GeWo '/ u selenium to 35 wt.% Arsenic) is divided and alternating parts are conditioned with a solution containing 5% N- Contains lauryl morpholine in isopropyl alcohol. The conditioning solution is applied with a cotton cloth and allowed to sit on the photoreceptor for about 5 minutes

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remain before excess condition! er connection with Isopropyl alcohol is removed. After removing excess conditioning compound, the photoreceptor becomes Rub dry with a soft cotton cloth in the areas where the conditioning agent has been applied. After conditioning, the photoreceptor is sensitized by touching a positive corotron, which operates at 8000 V. is kept loading. Measurements of the surface potential of the photoreceptor indicate that those areas exposed to N-laurylmorpholine conditioned, can carry a surface potential of about BOO V, whereas those regions of the Photoreceptors that have not been conditioned can only carry a surface potential of approximately 700 volts. The photoreceptor is then placed in a standard Xerox 4000 copier and various copies are made from it. Examination of these copies clearly indicates that those areas of the photoreceptor which are exposed to the. N-laurylmorpholine conditioned gave copies with improved density even after 4000 copying cycles. The photoreceptor is then removed and examined. It appears that the conditioned portions of the photoreceptor are essentially free of residual toner than those parts that have not been treated with conditioning solution, resulting in more effective cleaning of the wing cleaner indicates.

Example 2

The procedure of Example 1 is repeated except that a conditioning solution containing approximately 1 g of N-laurylmorpholine / 100 ml of isopropyl alcohol is used. Although there is some improvement in charge acceptance and noticed in the solid density evolution, it is evident that the extent of the improvement is much less than in Example 1.

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example

The procedure of Example 2 is repeated with the exception that the conditioning solution is deposited on the image layer of the electrophotographic Imaging material for a period of approximately 25 minutes prior to removal of any unabsorbed material Compounds with isopropyl alcohol can remain. The charge acceptance and the solid density development are improved compared to Example 2, but not comparable with the improvements of Example 1.

Example 4

The procedure of Example 1 is repeated with the exception that a conditioning solution is used which contains 15 g of N-laurylmorpholine / 100 contains g of isopropyl alcohol. Due to the increased viscosity of this conditioning solution, compared with that of Example 1, the application of a uniform film on the image layer is somewhat more difficult. After removing excess conditioning agents, the image layer is applied in the same way as in Example 1 described rated. Both the charge absorption and the fixed density development are worse than in the example 1. It is assumed that due to the increase in the Viscosity did not wet the conditioning compound as effectively as the conditioning solution of Example 1. The effectiveness of the conditioning compound is significantly reduced; this results in a significantly lower Effectiveness and complete absorption and adsorption on the image layer.

Example 5

The procedure of Example 1 is repeated except that N-caprylylmorpholine is substituted for N-laurylmorpholine will.

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example

The procedure of Example 1 is repeated with the exception that N-caprylmorpholine is substituted for N-laurylmorpholine. ,

Example 7

The procedure of Example 1 is repeated except that N-14yristylmorpholine is substituted for N-laurylmorpholine.

Example 6

The procedure of Example 1 is repeated with the exception that N-palmitylmorpholine is substituted for N-laurylmorpholine.

Example 9

The procedure of Example 1 is repeated except that N-3-tearylmorpholine is substituted for N-laurylmorpholine.

Example 10

The procedure of Example 1 is repeated except that N-arachidylmorpholine is substituted for N-laurylmorpholine
will.

Example 11

The procedure of Example 1 is repeated with the exception that N-behenylmorpholine is substituted for N-laurylmorpholine.

Example 12

The procedure of Example 1 is repeated with the exception that N-Li ^ nocerylmorpholine is substituted for N-laurylmorpholine
will.

Example 1-3

The procedure of Example 1 is repeated with the exception that N-cerotylmorpholine is substituted for N-laurylmorpholine.

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Example 14

To quantitatively determine the extent to which R-Laurylmorpholine reduces the frictional forces between the cleaning wing and the photoreceptor surface in Example 1, the photoreceptor is removed from the copier and installed in a test fixture. Part of the polyurethane wing is removed from the copier and installed in a holder of the test device. The United Weights of the wing and the holding device are approximately 60 g. The wing is placed on the surface of the photoreceptor placed (wing surface in contact with the photoreceptor = 20 mm χ 2.2 mm). When the wing is along the surface of the photoreceptor is withdrawn, the force required to move the wing increases when the wing from the conditioned to the unconditioned Part of the photoreceptor passes over. Such a change the force is determined by a simple spring scale (Ohaus, dial-type scale), which is mounted on the wing holder. From these measurements the coefficient of friction (/ u) for the conditioned surfaces of the drum is calculated; it ranges from about 0.023 to 0.030, and the coefficient of friction for the unconditioned portions of the Drum is calculated and ranges from about 0.08 to 0.10.

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Claims (34)

Claims 1. Method of improving the charge acceptance of a electrophotographic imaging material which contains a photoconductive layer, the amorphous selenium or selenium alloys contains, characterized in that there is a compound of the formula on the image layer in an amount effective to improve charge acceptance, wherein R is a saturated aliphatic hydrocarbon group means having from about 8 to about 30 carbon atoms. 2. The method according to claim 1, characterized in that the compound is N-laurylmorpholine. 3. The method according to claim 1, characterized in that the photoconductive imaging layer is a Contains selenium / arsenic alloy. 4. The method according to claim 1, characterized in that the photoconductive imaging layer
contains a selenium / tellurium alloy. 5 * The method according to claim 1, characterized in that about 0.2 to about 0.5 / ug of the above compound per square centimeter of the surface 'of the imaging layer are deposited. 6. The method according to claim 1, characterized in that a compound of the above formula to- 5Q9817 / 1CU4 is only dissolved in a lower alkyl alcohol and that then the resulting solution is applied to the surface of the imaging layer. 7. A method for improving the moisture resistance of an electrophotographic imaging material, the one photoconductive imaging layer containing amorphous selenium or selenium alloy, characterized in that there is at least one compound on the image layer the formula N
ι
R. wherein R is a saturated aliphatic hydrocarbon group having from about 8 to about 30 carbon atoms, deposited in an amount effective to improve moisture resistance. 8. The method according to claim 7, characterized in that the compound is N-laurylmorpholine. 9. The method according to claim 7, characterized in that the photoconductive imaging layer contains a selenium / arsenic alloy. 10. The method according to claim 7, characterized in that the photoconductive imaging layer a Contains selenium / tellurium alloy. 11. The method according to claim 7, characterized in that about 0.2 to about 0.5 / ug of the above compound / cm surface of the imaging layer deposited will. 509817/1 12. The method according to claim 7, characterized in that the compound of the above formula first is dissolved in a lower alkyl alcohol and that the resulting solution is applied to the surface of the imaging layer is applied. 13. A method for improving the abrasion resistance of an electrophotographic imaging material which is a photoconductive imaging layer containing amorphous selenium or contains selenium alloys, characterized in that that at least one compound of the formula wherein R is a saturated aliphatic hydrocarbon group having from about 8 to about 30 carbon atoms, deposited in an amount effective to improve abrasion resistance. 14. ' Process according to Claim 13, characterized in that the compound is H-laurylmorpholine. 15. The method according to claim I3, characterized in that the photoconductive imaging layer contains a selenium / arsenic alloy. 16. The method according to claim 13 »characterized in that the photoconductive imaging layer contains a selenium / tellurium alloy. 17. The method according to claim 13, characterized in that about 0.2 to about 0.5 / Ug of / 2 ' above compound / cm- surface of the Abbilaeschicht deposited will. 50981 11 1 OU 18. The method according to claim 13, characterized in that the compound of the above formula first is dissolved in a lower alkyl alcohol and that the resulting solution is applied to the surface of the imaging layer will. 19. A method for extending the useful life of an electrophotographic imaging material which is a photoconductive The image layer contains the selenium or selenium alloys contains, characterized in that at least one compound of the formula ■ N-ι wherein R is a saturated aliphatic carbon group having from about 8 to about 30 carbon atoms means deposited in an amount sufficient to extend the useful life. 20. The method according to claim 19 »thereby g e k e η η ζ e i c h η e t that the compound is N-laurylmorpholine. 21. The method according to claim 19, characterized in that the photoconductive imaging layer contains a selenium / arsenic alloy. 22. The method according to claim 19, characterized in that g e k e η η draw t that the photoconductive imaging layer contains a selenium / tellurium alloy. 23. The method according to claim 19, characterized ge ken n - ζ e ic h η e t that about 0.2 to about 0.5 / ug of the 2 ' above compound / cm surface of the imaging layer are deposited. 5098177 1044 24. The method according to claim 19, characterized in that a compound of the above formula first is dissolved in a lower alkyl alcohol and that then the resulting solution on the surface of the imaging layer is applied. 25.) An electrophotographic imaging material comprising a conductive substrate which, effectively in relation therewith, contains a photoconductive imaging layer which
contains amorphous selenium or selenium alloy, wherein the surface of the image layer deposited thereon a conditioning effective amount of at least one compound of
formula N ' • R wherein R is a saturated aliphatic hydrocarbon group having from about 8 to about 30 carbon atoms means. 26. Image material according to claim 25, characterized in that the compound is N-laurylmorpholine. 27. Image material according to claim 25, characterized in that the photoconductive image layer contains a selenium / arsenic alloy. 28. imaging material according to claim 25, characterized in that the photoconductive imaging layer contains a selenium / tellurium alloy. 29. imaging material according to claim 25, characterized in that. that about 0.2 to about 0.5 / Ug the 2 ' above compound / cm surface of the imaging layer deposited will. , 5Q9817 / 10U 30. Electrophotographic imaging process, thereby marked that one (a) provides an electrophotographic imaging material which includes a conductive substrate adhered thereto attached in operative relationship therewith having an image photoconductive layer comprising amorphous selenium or a selenium alloy contains, the surface of the imaging layer having deposited thereon: a conditioning agent Amount of at least one compound of the formula 0. CJ • Μι
R. wherein R is a saturated aliphatic carbon group having from about 8 to about 30 carbon atoms, and (b) forms a latent image on the photoreceptor. 31. The method according to claim 30, characterized in that the compound N-laurylmorpholine used. 32. The method according to claim 30, characterized in that the photoconductive imaging layer contains a selenium / arsenic alloy. 33. The method according to claim 30, characterized in that the photoconductive imaging layer contains a selenium / tellurium alloy. 34. The method according to claim 30, characterized in that about 0.2 to about 0.5 / ug of the 2 ' above compound / cm surface of the imaging layer are deposited. 509817/1