US3635705A - Multilayered halogen-doped selenium photoconductive element - Google Patents

Multilayered halogen-doped selenium photoconductive element Download PDF

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Publication number
US3635705A
US3635705A US830031A US3635705DA US3635705A US 3635705 A US3635705 A US 3635705A US 830031 A US830031 A US 830031A US 3635705D A US3635705D A US 3635705DA US 3635705 A US3635705 A US 3635705A
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selenium
plate
halogen
layer
doped
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US830031A
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Anthony J Ciuffini
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Xerox Corp
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Xerox Corp
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
    • G03G5/02—Charge-receiving layers
    • G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
    • G03G5/043—Photoconductive layers characterised by having two or more layers or characterised by their composite structure
    • G03G5/0433—Photoconductive layers characterised by having two or more layers or characterised by their composite structure all layers being inorganic

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  • ABSTRACT A xerographic plate having a two-layer photoconductive segment comprising a highly doped vitreous selenium transport layer of from about 20 to 200 microns in thickness and an overlaying control layer of at least about 5 microns thickness which comprises selenium.
  • the plate is characterized by low residual potential as well as exhibiting a minimum ghosting effeet.
  • the latent electrostatic image may then be developed and made visible by depositing finely divided electroscopic marking particles on the surface of the photoconductive insulating layer.
  • vitreous selenium xerographic plates still remain the most widely used in that they are capable of holding an electrostatic charge for long periods of time when not exposed to light, because they are relatively sensitive to light compared to other xerographic plates, and because of their durability to be reused hundreds or even thousands of times.
  • the vitreous selenium plate is somewhat limited than its spectral response which is very largely limited to the blue or near ultraviolet portion of the spectrum.
  • Residual potential is the voltage remaining on the plate after exposure to the erase lamp in a conventional xerographic cycle using a reuseable xerographic plate. More particularly, when a sensitized xerographic plate is exposed to light, the electrical potential undergoes an initial rapid decay, followed by a relatively slow decay. The plate voltage at the point beyond which no further light discharge occurs is called the residual potential. This potential may vary from zero to as much as 20 or 30 percent of the initial potential. A low residual potential is a desirable characteristic of xerographic plates because of the greater voltage contrast obtainable between background and darkened areas of the copy; that is, sufficient voltage contrast is required so as to effectively attract the development toner in a well-contrasted print.
  • a plate having ideal electrical characteristics would have a low dark discharge as well as low residual potential.
  • a plate having low residual potential is always desirable for satisfactory voltage contrast. lnactual practice, however, it has been difficult to produce a photoconductive material having the aforementioned electrical characteristics.
  • a xerographic plate having a double-layered photoconductive segment comprising a lower transport layer of vitreous selenium doped with a halogen and a relatively thin overlayer which consists of undoped vitreous selenium.
  • concentration of halogen in the lower transport layer ranges from about 60 to 10,000 p.p.m.
  • FIG. 1 is a schematic sectional view of one embodiment of a xerographic plate contemplated by the instant invention.
  • FIGS. 2 and 3 illustrate characteristic discharge curves for doped vitreous selenium at different recycling speeds.
  • FIG. 4 illustrates discharge curves for a halogen-doped vitreous selenium and an overcoated vitreous selenium plate of the instant invention.
  • FIG. 1 illustrates one embodiment of an improved xerographic plate according to this invention.
  • Reference character 11 designates a substrate or mechanical support.
  • the substrate may comprise a metal such as brass, aluminum, gold, platinum, steel, or the like. It may be of any convenient thickness, rigid or flexible, in the form of a sheet, web, cylinder, or the like, and may be coated with a thin layer of plastic. It may also comprise such other materials as metallized paper, plastic sheets covered with a thin coating of aluminum or copper iodine. or glass coated with a thin layer of chromium or tin oxide. It is usually preferred that the support member be somewhat electrically conductive or have a somewhat conductive surface and that it be strong enough to permit a certain amount of handling. In certain instances, however, support 11 need not be conductive or may be even dispensed with entirely. 1
  • Reference character 12 designates a storage layer which comprises high-purity vitreous selenium heavily doped with a halogen such as chlorine, fluorine, bromine, or iodine.
  • a halogen such as chlorine, fluorine, bromine, or iodine.
  • the halogen is present in relatively large amounts which are measured in parts per million. For the purposes of this invention concentrations from about 60 to 10,000 p.p.m. are preferred in order to obtain an effectively doped vitreous selenium layer. As heretofore indicated halogen dopant below 20 p.p.m. results in a residual buildup at high cycling speeds while concentrations above 10,000 are unnecessary to achieve the electrical properties desired in the instant invention.
  • Storage layer 12 may be in any suitable thickness used for conventional photoconductive layers. Typical thicknesses range from about 20 to 200 microns. A range of from about 40 to 80 microns is preferred since these are the thicknesses that are generally used in conventional xerographic machines.
  • Overlaying control layer 13 comprises undoped vitreous selenium in a thickness of from about 5 to 20 microns. Thicknesses below about 5 microns fail to effectively overcome the high dark discharge characteristics of the heavily halogenated vitreous selenium transport layer while thicknesses above 20 microns effectively masks the lower transport layer so that the chlorine doped selenium fails to function as a low residual photoreceptor.
  • the photoconductive portion of the plate of FIG. 1 is divided into two functional layers: (1) a highly doped transport layer which functions to prevent positive residual buildup during rapid cycling discharge, thereby ensuring charge contrast, and; (2) an overlaying control layer of more than 5 microns which effectively shields the highly halogenated layer from harmful radiation and thus prevents.
  • FIG. 2 there is a dramatic illustration of the effect of increased speed on the residual potential of a single layer vitreous selenium having moderate amounts of halogen.
  • the residual buildup of a vitreous selenium monolayer photoreceptor containing 20 p.p.m. chlorine dopant was measured by exposure to a cool white fluorescent light source at speeds of 5, 20, and 50 r.p.m. on an oxidized aluminum substrate in the form of a cylindrical drum approximately 4.75 inches in diameter by 10.2 inches long.
  • the residual potential was measured after the plate reached its maximum residual buildup which generally occurred after 30 to 40 cycles. Exposure values ranged from 0.03 to 30 foot-candle seconds at each speed.
  • FIG. 3 graphically demonstrates the advantages of using a highly doped vitreous selenium photoreceptor plate in rapid recycling machines.
  • the residual potential of a vitreous selenium monolayer photoreceptor containing p.p.m. chlorine is measured by discharging at speeds of 5, 20, and50 r.p.m. in the manner as described for FIG. 2. It can be clearly seen that discharge at each speed results in total dissipation of the surface charge effectively eliminating residual potential.
  • the curves of FIG. 3 clearly indicate the utility of the highly doped photoreceptor in rapid recycling machines.
  • FIG. 4 The effect of the overcoating of the instant invention on the discharge characteristics of highly doped vitreous selenium layer is demonstrated in FIG. 4.
  • the discharge characteristics of a vitreous selenium monolayer doped with 60 p.p.m. chlorine is graphically compared to the same monolayer overcoated with a S-micron layer of pure selenium in accordance with the present invention. It can be seen from FIG. 4 that the selenium overcoating has not altered the discharge characteristics to any great extent thus indicating that the selenium overcoating does not adversely affect the sensitivity of highly doped vitreous selenium photoreceptors.
  • selenium may be conveniently purchased to specification with the desired concentration of dopant already present.
  • Canadian Copper Refiners is one source of predoped'selenium.
  • the selenium may be doped by any conventional laboratory technique such as physically mixing the dopant with the selenium and vacuum evaporating the mixture onto the conductive substrate.
  • Bromine may be added in the form of liquid drops to the selenium which has been precooled.
  • Chlorine or fluorine may be added by admitting chlorine or fluorine gas to an evacuated tube containing selenium, which has been precooled, and maintaining the flow of gas until the selenium contains the desired amount of dopant.
  • halogen may be added to the selenium in the form of a compound of the selenium or with other compounds such as silver halides.
  • halogen-doped vitreous selenium plates were prepared in order to illustrate the dark discharge characteristics of highly doped plates.
  • Each plates contains a 50-micron-thick photoreceptor layer of halogen doped vitreous selenium and are chlorine doped to a concentration of 66 p.p.m.
  • plate 2 is overcoated with a 5-micron layer of undoped selenium.
  • the doped plates are then tested to measured their dark discharge rate under both rested and fatigued conditions. Both plates were rested overnight and mounted on an aluminum testing fixture in the form of a cylindrical drum approximately 4.75 inches by 10.2 inches long. For dark discharge values in the rested condition the plate was charged to an initial potential of 800 volts by means of a dual corotron and the rate of dark discharge measured at intervals of 4, l0, and 30 seconds. For fatigued values the mounted plates were exposed by means of a cool white fluorescent light source to 1,550 footcandle seconds for cycles. The fatigued plates were then charged to 800 volts on the sixth cycle and the dark discharge values measured in the same manner described above for the rested plates. The results are presented in table I.
  • EXAMPLE I An oxidized aluminum drum approximately 4.75 inches in diameter by 10.2 inches long having an arsenic-selenium photoreceptor with 66 ppm. chlorine was prepared and placed in a Xerox 813 Office Copier. An off-on switch was placed in series with the white light expose lamp and the preclean corotron and erase lamp were disconnected. With the drum rested overnight three exposures were made and the expose lamp shut off. In cycling without the exposure lamp a ghost image of the original copy appeared thereby indicating that the background areas had become persistently conductive and 0 background and darkened areas of the cop thereby contrasted with the darkened areas of the copy.
  • EXAMPLE Ill This same drum was then overcoated with a S-micron layer of pure undoped selenium and the above test repeated.
  • the resultant copy showed virtually no ghosting after the expose lamp has been shut off thereby indicating that the pure selenium overcoating prevented the contrast between the
  • the plates of the instant invention may he prepared by any of the well-known conventional techniques such as those set forth in U.S. Pat. No. 2,803,542 to Ullrich, U.S. Pat. No. 2,822,300 to Mayer et al., or U.S. Pat. No. 3,312,548 to Straughan. Briefly, such techniques involve forming suitable mixtures of selenium, arsenic and halogen in a container and reacting said elements at elevated temperatures. The resulting alloy is then cooled and applied to a suitable conductive supporting base by vacuum evaporation.
  • the transport layer is also evaporated onto the conductive substrate by any conventional technique such as those shown by U.S. Pat. No. 2,753,278 to Bixby et al. and U.S. Pat. No. 2,970,906 to Bixby. If desired, both the transport layer and control layer may be evaporated sequentially without breaking the vacuum. This avoids the possible danger of contaminating the surface of the plate.
  • a xerographic plate including a two-layer photoconductive segment, said first layer comprising halogen doped vitreous selenium in a thickness of about 40-80 microns, with the dopant being present in a concentration of from about about 60-l0,000 parts per million, and an undoped substantially clear vitreous selenium layer of from about 520 microns in thickness overlaying said first layer.
  • the method of imaging comprising a. providing a xerographic plate having a two-layered photoconductive segment, said segment comprising a first layer 40-80 microns thick comprising vitreous selenium doped with 60-l0,000 parts per million of halogen, and an overlaying layer about 5 to 20 microns in thickness comprising undoped selenium,
  • halogen dopant comprises chlorine in a concentration of from about 60 to 10,000 parts per million.

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  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Photoreceptors In Electrophotography (AREA)
  • Light Receiving Elements (AREA)
US830031A 1969-06-03 1969-06-03 Multilayered halogen-doped selenium photoconductive element Expired - Lifetime US3635705A (en)

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JP (1) JPS492629B1 (enrdf_load_stackoverflow)
DE (1) DE2027323A1 (enrdf_load_stackoverflow)
FR (1) FR2049828A5 (enrdf_load_stackoverflow)
GB (1) GB1311329A (enrdf_load_stackoverflow)
NL (1) NL7008008A (enrdf_load_stackoverflow)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4183748A (en) * 1972-07-29 1980-01-15 Canon Kabushiki Kaisha Method of removing surface ionic impurities on inorganic photoconductive material
US4286033A (en) * 1980-03-05 1981-08-25 Xerox Corporation Trapping layer overcoated inorganic photoresponsive device
US4287279A (en) * 1980-03-05 1981-09-01 Xerox Corporation Overcoated inorganic layered photoresponsive device and process of preparation
US4297424A (en) * 1980-03-05 1981-10-27 Xerox Corporation Overcoated photoreceptor containing gold injecting layer
US4315063A (en) * 1977-11-17 1982-02-09 Canon Kabushiki Kaisha Electrophotographic photosensitive member having a halogen containing charge injection layer
US4318973A (en) * 1980-03-05 1982-03-09 Xerox Corporation Overcoated inorganic layered photoresponsive device and process of use
US4330609A (en) * 1980-03-05 1982-05-18 Xerox Corporation Method of imaging a trapping layer overcoated inorganic photoresponsive device
US4330610A (en) * 1980-03-05 1982-05-18 Xerox Corporation Method of imaging overcoated photoreceptor containing gold injecting layer
US4338387A (en) * 1981-03-02 1982-07-06 Xerox Corporation Overcoated photoreceptor containing inorganic electron trapping and hole trapping layers
US4343881A (en) * 1981-07-06 1982-08-10 Savin Corporation Multilayer photoconductive assembly with intermediate heterojunction
US4554230A (en) * 1984-06-11 1985-11-19 Xerox Corporation Electrophotographic imaging member with interface layer
US4572883A (en) * 1984-06-11 1986-02-25 Xerox Corporation Electrophotographic imaging member with charge injection layer
US4609605A (en) * 1985-03-04 1986-09-02 Xerox Corporation Multi-layered imaging member comprising selenium and tellurium
US6366751B1 (en) * 1999-09-17 2002-04-02 Ricoh Company, Ltd. Image forming apparatus including preselected range between charge injection layer and voltage potential
US20060121377A1 (en) * 2004-12-03 2006-06-08 Xerox Corporation Multi-layer photoreceptor
US20060134537A1 (en) * 2004-12-17 2006-06-22 Lexmark International, Inc. Increased silicon microspheres in charge transfer layers

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3034034B1 (fr) * 2015-03-26 2017-04-28 Piercan Dispositif bidirectionnel de changement d'un gant de manipulation et procede de remplacement de ce gant par translation

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3041166A (en) * 1958-02-12 1962-06-26 Xerox Corp Xerographic plate and method
US3312548A (en) * 1963-07-08 1967-04-04 Xerox Corp Xerographic plates

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3041166A (en) * 1958-02-12 1962-06-26 Xerox Corp Xerographic plate and method
US3312548A (en) * 1963-07-08 1967-04-04 Xerox Corp Xerographic plates

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Schaffert, Electrophotography, 1965, pp. 231 233. *

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4183748A (en) * 1972-07-29 1980-01-15 Canon Kabushiki Kaisha Method of removing surface ionic impurities on inorganic photoconductive material
US4315063A (en) * 1977-11-17 1982-02-09 Canon Kabushiki Kaisha Electrophotographic photosensitive member having a halogen containing charge injection layer
US4286033A (en) * 1980-03-05 1981-08-25 Xerox Corporation Trapping layer overcoated inorganic photoresponsive device
US4287279A (en) * 1980-03-05 1981-09-01 Xerox Corporation Overcoated inorganic layered photoresponsive device and process of preparation
US4297424A (en) * 1980-03-05 1981-10-27 Xerox Corporation Overcoated photoreceptor containing gold injecting layer
US4318973A (en) * 1980-03-05 1982-03-09 Xerox Corporation Overcoated inorganic layered photoresponsive device and process of use
US4330609A (en) * 1980-03-05 1982-05-18 Xerox Corporation Method of imaging a trapping layer overcoated inorganic photoresponsive device
US4330610A (en) * 1980-03-05 1982-05-18 Xerox Corporation Method of imaging overcoated photoreceptor containing gold injecting layer
US4338387A (en) * 1981-03-02 1982-07-06 Xerox Corporation Overcoated photoreceptor containing inorganic electron trapping and hole trapping layers
US4343881A (en) * 1981-07-06 1982-08-10 Savin Corporation Multilayer photoconductive assembly with intermediate heterojunction
US4554230A (en) * 1984-06-11 1985-11-19 Xerox Corporation Electrophotographic imaging member with interface layer
US4572883A (en) * 1984-06-11 1986-02-25 Xerox Corporation Electrophotographic imaging member with charge injection layer
US4609605A (en) * 1985-03-04 1986-09-02 Xerox Corporation Multi-layered imaging member comprising selenium and tellurium
US6366751B1 (en) * 1999-09-17 2002-04-02 Ricoh Company, Ltd. Image forming apparatus including preselected range between charge injection layer and voltage potential
US6625409B2 (en) 1999-09-17 2003-09-23 Ricoh Company, Ltd. Image forming apparatus having a diamond-like structure surface protection layer on a photoconductive layer
US6654579B2 (en) 1999-09-17 2003-11-25 Ricoh Company, Ltd. Image forming apparatus including diamond-like or amorphous structure containing hydrogen surface protection layer
US20060121377A1 (en) * 2004-12-03 2006-06-08 Xerox Corporation Multi-layer photoreceptor
US7531284B2 (en) * 2004-12-03 2009-05-12 Xerox Corporation Multi-layer photoreceptor
US20060134537A1 (en) * 2004-12-17 2006-06-22 Lexmark International, Inc. Increased silicon microspheres in charge transfer layers

Also Published As

Publication number Publication date
JPS492629B1 (enrdf_load_stackoverflow) 1974-01-22
NL7008008A (enrdf_load_stackoverflow) 1970-12-07
GB1311329A (en) 1973-03-28
DE2027323A1 (de) 1972-02-17
FR2049828A5 (enrdf_load_stackoverflow) 1971-03-26

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