US3867143A - Electrophotographic photosensitive material - Google Patents
Electrophotographic photosensitive material Download PDFInfo
- Publication number
- US3867143A US3867143A US414820A US41482073A US3867143A US 3867143 A US3867143 A US 3867143A US 414820 A US414820 A US 414820A US 41482073 A US41482073 A US 41482073A US 3867143 A US3867143 A US 3867143A
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- United States
- Prior art keywords
- layer
- photosensitive member
- photoconductive
- photoconductive layer
- insulating layer
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- Expired - Lifetime
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- 239000000463 material Substances 0.000 title description 20
- 239000011669 selenium Substances 0.000 claims abstract description 20
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 claims abstract description 18
- 229910052711 selenium Inorganic materials 0.000 claims abstract description 18
- 239000000956 alloy Substances 0.000 claims abstract description 8
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 8
- 229910052787 antimony Inorganic materials 0.000 claims abstract description 6
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 claims abstract description 6
- 230000005855 radiation Effects 0.000 claims description 8
- 229910052732 germanium Inorganic materials 0.000 claims description 3
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 claims description 2
- 239000000126 substance Substances 0.000 abstract description 17
- 238000000034 method Methods 0.000 description 29
- 235000011649 selenium Nutrition 0.000 description 16
- 229940091258 selenium supplement Drugs 0.000 description 16
- 238000007599 discharging Methods 0.000 description 10
- 230000035945 sensitivity Effects 0.000 description 10
- 238000001228 spectrum Methods 0.000 description 6
- OQRNKLRIQBVZHK-UHFFFAOYSA-N selanylideneantimony Chemical compound [Sb]=[Se] OQRNKLRIQBVZHK-UHFFFAOYSA-N 0.000 description 5
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 238000010276 construction Methods 0.000 description 3
- 238000002425 crystallisation Methods 0.000 description 3
- 230000008025 crystallization Effects 0.000 description 3
- 241000149947 Coronarchaica corona Species 0.000 description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000001747 exhibiting effect Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229910052714 tellurium Inorganic materials 0.000 description 2
- 229910052718 tin Inorganic materials 0.000 description 2
- ZNQVEEAIQZEUHB-UHFFFAOYSA-N 2-ethoxyethanol Chemical compound CCOCCO ZNQVEEAIQZEUHB-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 206010034972 Photosensitivity reaction Diseases 0.000 description 1
- 229910001245 Sb alloy Inorganic materials 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000002140 antimony alloy Substances 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- 229920002301 cellulose acetate Polymers 0.000 description 1
- 239000002800 charge carrier Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- 239000002241 glass-ceramic Substances 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000036211 photosensitivity Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 229920003227 poly(N-vinyl carbazole) Polymers 0.000 description 1
- 229920005668 polycarbonate resin Polymers 0.000 description 1
- 239000004431 polycarbonate resin Substances 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 229920006267 polyester film Polymers 0.000 description 1
- 229920001225 polyester resin Polymers 0.000 description 1
- 239000004645 polyester resin Substances 0.000 description 1
- 229920013716 polyethylene resin Polymers 0.000 description 1
- 229920006254 polymer film Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000001235 sensitizing effect Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000010944 silver (metal) Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 229910002058 ternary alloy Inorganic materials 0.000 description 1
- 229910052716 thallium Inorganic materials 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 230000004304 visual acuity Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
Classifications
-
- 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
- G03G5/08—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor characterised by the photoconductive material being inorganic
- G03G5/082—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor characterised by the photoconductive material being inorganic and not being incorporated in a bonding material, e.g. vacuum deposited
- G03G5/08207—Selenium-based
-
- 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
- G03G5/14—Inert intermediate or cover layers for charge-receiving layers
- G03G5/147—Cover layers
- G03G5/14704—Cover layers comprising inorganic material
-
- 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
- G03G5/14—Inert intermediate or cover layers for charge-receiving layers
- G03G5/147—Cover layers
- G03G5/14708—Cover layers comprising organic material
- G03G5/14713—Macromolecular material
- G03G5/14717—Macromolecular material obtained by reactions only involving carbon-to-carbon unsaturated bonds
- G03G5/1473—Polyvinylalcohol, polyallylalcohol; Derivatives thereof, e.g. polyvinylesters, polyvinylethers, polyvinylamines
Definitions
- ABSTRACT 1 mainly three layers such as a supportlayer, a photoconductive layer and an insulating layer, or mainly four layers such as a conductive layer, an insulating layer, a photoconductive layer and an insulating layer.
- This invention relates to an electrophotographic photosensitive member, and more particularly, to an electrophotographic photosensitive member mainly composed of support, photoconductive layer and insulating layer and capable of forming electrostatic image on the surface of the insulating layer.
- amorphous selenium in Xerox process and zinc oxide in Electrofax process.
- those photoconductive materials have various disadvantages to be solved, for example, when amorphous selenium is used as photosensitive member for a long time, the amorphous selenium is converted to a more stable metallic selenium, and thereby the physical properties are changed and the dark resistance and physical strength are lowered.
- the solenium can not be used any more and thus the life of the photosensitive member is substantially determined by the conversion of the amorphous state to metallic selenium state.
- amorphous selenium In addition to such deterioration caused by crystallization of amorphous selenium, amorphous selenium is hardly sensitive to a long wave length region with respect to spectrum sensitivity and thereby the light source of imagewise exposure is restricted. Neither amorphous sele nium is suitable for reproduction of colored original image nor color-reproduction.
- a photosensitive member having amorphous selenium as the photoconductive layer is usually made by depositing amorphous selenium on an electrically conductivesupport, and the photosensitive member thus produced is subjected to electrophotographic processes such as charging, exposure, developing and transferring and such processes are effected on the surface of the photoconductivelayer. Therefore, the surface of the photoconductive layer is damaged by various external factors such as effect of temperature, oxidation with air, abrasion, pressure and the like, and thereby the life of the photosensitive member is shortened and furthermore the damaged portion as mentioned above becomes crystal seed and accelerate crystallization of the amorphous selenium and thus the life of the photosensitive member is further shortened.
- electrophotographic processes for example, inventions disclosed in U.S. Ser. No. 563899 filed July 8, 1966 and U.S. Ser. No. 571538 filed Aug. 10, 1966.
- These electrophotographic processes comprise employing a photosensitive member having an insulating layer closely contacted with a photoconductive layer, and effecting three steps, that is, primary charging, expopsure simultaneously with secondary charging of a polarity opposite to that in the primary charging, or A.C. discharging, and whole surface exposure, to form electrostatic images of high contrast on the surface of insulating layer.
- the photosensitive member used in these processes is composed mainly of three layers. i.e.
- insulating layer, photoconductive layer, and conductive or insulating support or composed mainly of four layers, i.e., insulating layer, photoconductive layer, insulating layer and conductive layer, and at least one layer adjacent to the photoconductive layer should be transparent to a radiation to which the photoconductive layer is sensitive.
- electrostatic images are not formed directly on the photoconductive layer, but on the insulating layer, and various electrophotographic procedures such as developing, transferring, cleaning and the like are effected on the surface of the insulating layer. Therefore, the photoconductive layer is hardly damaged in this photosensitive member so that neither the crystallization of amorphous selenium occurs nor is accelerated.
- the photosensitive member is hardly deteriorated and shows stable performance for a long time.
- such photosensitive member having an insulating layer on a photoconductive layer does not have both charge retaining function and photoconductive function in the photoconductive layer, but the two functions are allotted to the insulating layer and the photoconductive layer and thereby the burden to the photosensitive layer is lightened.
- a highly sensitive material is generally of low electrical resistance and the charge retaining ability is low before imagewise exposure, but the process employing the above-mentioned photosensitive member can effectively utilize a highly sensitive material of low resistance which is not preferred in usual electrophotographic processes.
- the photoconductive material can be selected from wide material sources without restricted by various electric characteristics.
- This invention relates to a photosensitive member having an insulating layer on a photoconductive layer.
- An object of this invention is to provide a photosensitive member of high sensitivity and exhibiting stably the function for a long time.
- Another object of this invention is to provide a photosensitive member in which the sensitivity and the spectrum sensitivity region can be relatively easilycontrolled in accordance with the required photoconductive characteristics.
- a further object of this invention is to provide a photosensitive member having high resolving power and strong surface.
- a further object of this invention is to provide a photosensitive member which is composed mainly of support, photoconductive layer and insulating layer in which the photoconductive layer of a photosensitive member containing an insulating layer on which surface electrostatic images are formed, is an alloy comprising at least selenium, antimony and electric property controlling substance and is in a glass state.
- the photoconductive layer of the photosensitive member of this invention contains an alloy comprising mainly selenium-antimony and additionally an electric property controlling substance.
- the electric property controlling substance used in this invention is a substance which can impart a sensitizing effect to and widen the spectrum sensitivity region of the amorphous selenium-antimony system exhibiting stably the photoconductive property for a long time and can form a glassy alloy with the seleniumantimony system.
- electric property controlling substance are Cu, Ag, Au, Zn, Cd, Hg, Ga, In, Tl, Ge, Si, Sn, Pb, Bi, S, Te and the like and oxides thereof. in practical use, more than one of them may be used in combination.
- the change of electric property of the seleniumantimony system photoconductive material caused by adding such electric property controlling substance thereto is similar to that caused by adding a metallic sensitizer to an inorganic photoconductive material. That is, by adding the electric property controlling substance, the sensitivity and spectrum sensitivity region of the selenium-antimony system can be enhanced, but often the resistance in dark place is adversely lowered and this unfavorable effect impairs the electrostatic latent image retaining ability in electrophotographic processes. Therefore, if the photoconductive layer of this invention is applied to a conventional photosensitive member comprising a photoconductive layer laminated on a support, the construction of the photosensitive layer is often seriously limited due to lowering of charge retaining ability caused by the addition of the electric property controlling substance.
- the photoconductive layer should have a resistance (at dark place) sufficient to process a charge retaining ability and the resistance is higher than about IO Q-Cm. Since the addition of an electric property controlling substance lowers the electric properties such as resistance in many cases, the addition of an electric property controlling substance to the photoconductive layer is substantially limited from practical point of view.
- the charge retaining ability is attributed to the insulating layer and the photoconductive layer is requested only to have an excellent photoconductivity and therefore, the limitations as mentioned above are not requested.
- the electric property controlling substance can be optionally selected and prepared in accordance with the requested photoconductivity.
- the amount of the electric property controlling substance to be added to the selenium-antimony alloy is fundamentally restricted by the two factors, one is that the resistivity of photoconductive layer is not lower than 1 X lOQ.cm and the other is that the photoconductive layer is glassy. In view of the two factors as above, the amount of the electric property controlling substance to be added is relatively small, but such small amount can effectively improve electric properties, mainly sensitivity.
- the thickness of photoconductive layer preferably ranges from to 300 t.
- photoconductive layer of photosensitive member according to this invention is described. It is not yet fully understood the reason why the photoconductive material comprising fundamentally selenium, antimony and electric property controlling substance shows high sensitivity and wide spectrum photosensitivity region.
- the photoconductive material used in electrophotography is amorphous, but it can be handled in a similar to photosemiconductor.
- the electric property controlling substance behaves as impurity for semiconductor with respect to the selenium-antimony material and makes a level corresponding to so-called impurity energy level and this is excited by a radiation energy of relatively long wave length such as, for example, 700 mu to form easily charge carriers and as the result, there is obtained a photoconductive material having high sensitivity and wide spectrum photosensitive region.
- the insulating layer in the photosensitive member of this invention is preferably of high resistance, capable of retaining electric charge, and of large abrasion resistance.
- the insulating layer are high polymer films such as film offluorine containing resin, polycarbonate resin, polyethylene resin, cellulose acetate resin, polyester resin and the like, or inorganic materi als such as glass ceramics of SiO;, Aigog and the like.
- the insulating layer When the exposure is effected through the insulating layer, the insulating layer should be transparent to a radiation to which the photosensitive layer is sensitive, but when the exposure is effected from a side opposite to the insulating layer with respect to the photoconductive layer, it is not necessarily transparent to the radiation, but opaque insulating layer may be also used. However, in the latter case the support should be transparent. Further, the thickness of insulating layer ranges preferably from 6 to 50 ,u.
- the-support used in this invention there may be mentioned, for example, a conductive support, insulating support or a support comprising a conductive layer laminated with an insulating layer.
- an insulating support when used, electrostatic images can be formed on both sides of the photosensitive member and it is preferable to employ a double corona discharging system capable of charging the photosensitive member from both sides.
- the photosensitive member when a support composed of an insulating layer laminated with a conduc tive layer is used, the photosensitive member is fundamentally composed of four layers, that is, an insulating layer, a photoconductive layer, an insulating layer and a conductive layer.
- any supporting material having conductivity may be selected from wide sources.
- metallic conductive material such as tin, copper, aluminum and the like and a hygroscopic paper and an aluminum laminated paper.
- any supporting material may be used regardless inorganic and organic natures as far as the material is of insulating property. It is not necessary that the insulating support satisfies the conditions as requested for the insulating layer as mentioned above. Naturally the insulating support may be the same material as that of the insulating layer.
- the insulating support When the insulating support is used in a photosensitive member which is used in such a process that the exposure is effected from the support side, it is necessary that the insulating support is transparent to a radiation to which the photoconductive layer is sensitive. Furthermore, the above mentioned materials may be used for a support consisting of an insulating layer laminated with a conductive layer. When transparency is requested, there may be used transparent conductive material such as Nesa glass, polyvinylcarbazole and the like.
- EXAMPLE 1 A mixture of Se of high purity (99.99%), 72 parts by weight, Sb parts by weight, and Te 8 parts is sealed in a vacuum quartz tube, heated and melted at 500C for about 6 hours to form a uniform dispersion system. The resulting melted product is poured into a distilled water to form powder solid matter followed by drying sufficiently.
- the alloy thus obtained is deposited on an aluminum base plate maintained at 60 to 80C to form a glassy thin film, and thus a photoconductive layer of about 60 y. thick is obtained. Then, a polyester film of p. thick is ad hered to the photoconductive layer with epoxy resin to produce a highly sensitive photosensitive plate.
- Example 2 The procedure of Example 1 is repeated by using a mixture of Se 85 parts by weight, Sb 10 parts by weight and Ge 5 parts by weight in phase of Se, Sb and Te to 20 light of about 10 lu x to form latent images having electrostatic contrast of about 1,000V.
- An example of another method is that the secondary corona discharging as mentioned above is effected by A.C. corona discharging.
- An electrostatic contrast of about 600V is obtained by applying a primary corona discharging of7l(V and a secondary A.C. corona discharging of 5.8KV.
- Process A refers to an electrophotographic process comprising the steps, positive primary charging, negative secon dary charging direct exposure, development and radiation (recovering the decay of photosensitive member by irradiating infrared ray etc.)
- Process G refers to an electrophotographic process comprising the steps, positive primary charging, A.C. discharging simultaneously with exposure, whole surface irradiation, developing and irradiation.
- the photosensitive plates produced as above are used for forming electrostatic images as follows.
- the 40 polarity of voltage to be applied is selected appropriately in accordance with the type of photoconductivity of the photosensitive plate, for example, when the photoconductive layer is preferably of N-type, the primary charging is positive while when it is of p-type, the primary charging is preferably negative.
- the electrostatic image forming procedure is explained, for example, by using a photosensitive plate containing a photoconductive layer of ternary alloy of Se-S- b-Te.
- the surface of insulating layer of the photosensitive plate is charged to about-2,000V with a corona discharging of 6KV, and exposed at about one lux.sec simultaneously charged by a secondary corona discharging of +6KV and then the whole surface of the photosensitive member is uniformly irradiated with a What is claimed is:
- An electrophotographic photosensitive member comprising a support layer, a photoconductive layeroverlying the support layer and an insulating overlying the photoconductive layer and at least one of the layers adjacent to the photoconductive layer being transparerit to a radiation to which the photoconductive layer is sensitive, characterized in that the photoconductive layer comprises an amorphous glassy alloy containing about 72 by weight of selenium, about 10 20% by weight of antimony and about 5% by weight of germanium and has a resistivity at dark place of not less than 1X10 ohm-cm.
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- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- General Physics & Mathematics (AREA)
- Inorganic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Photoreceptors In Electrophotography (AREA)
Abstract
A photoconductive glassy alloy containing selenium, antimony and an electric property controlling substance is used in a photoconductive layer of a photosensitive member for electrophotography comprising mainly three layers such as a support layer, a photoconductive layer and an insulating layer, or mainly four layers such as a conductive layer, an insulating layer, a photoconductive layer and an insulating layer.
Description
States Patent [191 Tanaka et al.
[ ELECTROPHOTOGRAPHIC PHOTOSENSITIVE MATERIAL [75] Inventors: Hiroshi Tanaka; Takashi Saito, both of Tokyo, Japan [73] Assignee: Canon Kabushiki Kaisha, Tokyo,
Japan [22] Filed: Nov. 12, 1973 [21] Appl. No.: 414,820
Related US. Application Data [63] Continuation of Ser. No. 256,198, May 23, 1972, abandoned, which is a continuation of Ser. No. 1,867, Jan. 9, 1970, abandoned.
[30] Foreign Application Priority Data Jan. 17, 1969 Japan 44-3262 [52] US. Cl. 96/15 [51] Int. Cl U G03g 5/04 [58] Field of Search 96/15, 1 R; 75/134 G [56] References Cited UNITED STATES PATENTS 2,745,327 4/1956 Mengali 96/15 [451 Feb. 18, 1975 3,427,157 2/1969 Cerlon et al. 96/l .5 3,490,903 1/1970 Meyers et al. 96/1 .5 3,524,745 8/1970 Cerlon et al.. 96/'l.5 3,769,010 10/1973 Hanada 96/15 Primary Examiner-Norman G. Torchin Assistant Examiner-John L. Goodrow Attorney, Agent, or Firm Fitzpatrick, Cella, Harper & Scinto [5 7] ABSTRACT 1 mainly three layers such as a supportlayer, a photoconductive layer and an insulating layer, or mainly four layers such as a conductive layer, an insulating layer, a photoconductive layer and an insulating layer.
3 Claims, N0 Drawings 1 ELECTROPHOTOGRAPHIC PHOTOSENSITIVE MATERIAL This is a continuation of application Ser. No. 256,198, filed May 23, 1972 which was a continuation of Ser. No. 1,867, filed Jan. 9, 1970, both of which are now abandoned.
This invention relates to an electrophotographic photosensitive member, and more particularly, to an electrophotographic photosensitive member mainly composed of support, photoconductive layer and insulating layer and capable of forming electrostatic image on the surface of the insulating layer.
Heretofore, as photoconductive substances for photosensitive member used in conventioinal electropho tographic process, there have been well known amorphous selenium in Xerox process and zinc oxide in Electrofax process. However, those photoconductive materials have various disadvantages to be solved, for example, when amorphous selenium is used as photosensitive member for a long time, the amorphous selenium is converted to a more stable metallic selenium, and thereby the physical properties are changed and the dark resistance and physical strength are lowered. As the result, the solenium can not be used any more and thus the life of the photosensitive member is substantially determined by the conversion of the amorphous state to metallic selenium state. In addition to such deterioration caused by crystallization of amorphous selenium, amorphous selenium is hardly sensitive to a long wave length region with respect to spectrum sensitivity and thereby the light source of imagewise exposure is restricted. Neither amorphous sele nium is suitable for reproduction of colored original image nor color-reproduction.
A photosensitive member having amorphous selenium as the photoconductive layer is usually made by depositing amorphous selenium on an electrically conductivesupport, and the photosensitive member thus produced is subjected to electrophotographic processes such as charging, exposure, developing and transferring and such processes are effected on the surface of the photoconductivelayer. Therefore, the surface of the photoconductive layer is damaged by various external factors such as effect of temperature, oxidation with air, abrasion, pressure and the like, and thereby the life of the photosensitive member is shortened and furthermore the damaged portion as mentioned above becomes crystal seed and accelerate crystallization of the amorphous selenium and thus the life of the photosensitive member is further shortened.
The present applicant has already developed various electrophotographic processes, for example, inventions disclosed in U.S. Ser. No. 563899 filed July 8, 1966 and U.S. Ser. No. 571538 filed Aug. 10, 1966. These electrophotographic processes comprise employing a photosensitive member having an insulating layer closely contacted with a photoconductive layer, and effecting three steps, that is, primary charging, expopsure simultaneously with secondary charging of a polarity opposite to that in the primary charging, or A.C. discharging, and whole surface exposure, to form electrostatic images of high contrast on the surface of insulating layer. The photosensitive member used in these processes is composed mainly of three layers. i.e. insulating layer, photoconductive layer, and conductive or insulating support, or composed mainly of four layers, i.e., insulating layer, photoconductive layer, insulating layer and conductive layer, and at least one layer adjacent to the photoconductive layer should be transparent to a radiation to which the photoconductive layer is sensitive. Unlike conventional Carlson process, in this photosensitive member electrostatic images are not formed directly on the photoconductive layer, but on the insulating layer, and various electrophotographic procedures such as developing, transferring, cleaning and the like are effected on the surface of the insulating layer. Therefore, the photoconductive layer is hardly damaged in this photosensitive member so that neither the crystallization of amorphous selenium occurs nor is accelerated. Therefore, the photosensitive member is hardly deteriorated and shows stable performance for a long time. In such photosensitive member having an insulating layer on a photoconductive layer does not have both charge retaining function and photoconductive function in the photoconductive layer, but the two functions are allotted to the insulating layer and the photoconductive layer and thereby the burden to the photosensitive layer is lightened. In other words, a highly sensitive material is generally of low electrical resistance and the charge retaining ability is low before imagewise exposure, but the process employing the above-mentioned photosensitive member can effectively utilize a highly sensitive material of low resistance which is not preferred in usual electrophotographic processes. As the result, according to such process, the photoconductive material can be selected from wide material sources without restricted by various electric characteristics.
This invention relates to a photosensitive member having an insulating layer on a photoconductive layer.
An object of this invention is to provide a photosensitive member of high sensitivity and exhibiting stably the function for a long time.
Another object of this invention is to provide a photosensitive member in which the sensitivity and the spectrum sensitivity region can be relatively easilycontrolled in accordance with the required photoconductive characteristics. a
A further object of this invention is to provide a photosensitive member having high resolving power and strong surface.
A further object of this invention is to provide a photosensitive member which is composed mainly of support, photoconductive layer and insulating layer in which the photoconductive layer of a photosensitive member containing an insulating layer on which surface electrostatic images are formed, is an alloy comprising at least selenium, antimony and electric property controlling substance and is in a glass state. The photoconductive layer of the photosensitive member of this invention contains an alloy comprising mainly selenium-antimony and additionally an electric property controlling substance.
The electric property controlling substance used in this invention is a substance which can impart a sensitizing effect to and widen the spectrum sensitivity region of the amorphous selenium-antimony system exhibiting stably the photoconductive property for a long time and can form a glassy alloy with the seleniumantimony system.
Representative examples of the: electric property controlling substance are Cu, Ag, Au, Zn, Cd, Hg, Ga, In, Tl, Ge, Si, Sn, Pb, Bi, S, Te and the like and oxides thereof. in practical use, more than one of them may be used in combination.
The change of electric property of the seleniumantimony system photoconductive material caused by adding such electric property controlling substance thereto is similar to that caused by adding a metallic sensitizer to an inorganic photoconductive material. That is, by adding the electric property controlling substance, the sensitivity and spectrum sensitivity region of the selenium-antimony system can be enhanced, but often the resistance in dark place is adversely lowered and this unfavorable effect impairs the electrostatic latent image retaining ability in electrophotographic processes. Therefore, if the photoconductive layer of this invention is applied to a conventional photosensitive member comprising a photoconductive layer laminated on a support, the construction of the photosensitive layer is often seriously limited due to lowering of charge retaining ability caused by the addition of the electric property controlling substance. That is, in a photosensitive member composed of a photoconductive layer laminated on a support, the photoconductive layer should have a resistance (at dark place) sufficient to process a charge retaining ability and the resistance is higher than about IO Q-Cm. Since the addition of an electric property controlling substance lowers the electric properties such as resistance in many cases, the addition of an electric property controlling substance to the photoconductive layer is substantially limited from practical point of view.
On the other hand, according to the present invention, the charge retaining ability is attributed to the insulating layer and the photoconductive layer is requested only to have an excellent photoconductivity and therefore, the limitations as mentioned above are not requested. And the electric property controlling substance can be optionally selected and prepared in accordance with the requested photoconductivity.
The amount of the electric property controlling substance to be added to the selenium-antimony alloy is fundamentally restricted by the two factors, one is that the resistivity of photoconductive layer is not lower than 1 X lOQ.cm and the other is that the photoconductive layer is glassy. In view of the two factors as above, the amount of the electric property controlling substance to be added is relatively small, but such small amount can effectively improve electric properties, mainly sensitivity. The thickness of photoconductive layer preferably ranges from to 300 t.
In the foregoing, the construction of photoconductive layer of photosensitive member according to this invention is described. It is not yet fully understood the reason why the photoconductive material comprising fundamentally selenium, antimony and electric property controlling substance shows high sensitivity and wide spectrum photosensitivity region. However, the photoconductive material used in electrophotography is amorphous, but it can be handled in a similar to photosemiconductor. Therefore, it is considered that the electric property controlling substance behaves as impurity for semiconductor with respect to the selenium-antimony material and makes a level corresponding to so-called impurity energy level and this is excited by a radiation energy of relatively long wave length such as, for example, 700 mu to form easily charge carriers and as the result, there is obtained a photoconductive material having high sensitivity and wide spectrum photosensitive region.
Another construction of photosensitive member according to this invention is described below. Firstly, the insulating layer in the photosensitive member of this invention is preferably of high resistance, capable of retaining electric charge, and of large abrasion resistance. Examples of the insulating layer are high polymer films such as film offluorine containing resin, polycarbonate resin, polyethylene resin, cellulose acetate resin, polyester resin and the like, or inorganic materi als such as glass ceramics of SiO;, Aigog and the like. When the exposure is effected through the insulating layer, the insulating layer should be transparent to a radiation to which the photosensitive layer is sensitive, but when the exposure is effected from a side opposite to the insulating layer with respect to the photoconductive layer, it is not necessarily transparent to the radiation, but opaque insulating layer may be also used. However, in the latter case the support should be transparent. Further, the thickness of insulating layer ranges preferably from 6 to 50 ,u.
As the-support used in this invention, there may be mentioned, for example, a conductive support, insulating support or a support comprising a conductive layer laminated with an insulating layer. Further, when an insulating support is used, electrostatic images can be formed on both sides of the photosensitive member and it is preferable to employ a double corona discharging system capable of charging the photosensitive member from both sides. Furthermore, when a support composed of an insulating layer laminated with a conduc tive layer is used, the photosensitive member is fundamentally composed of four layers, that is, an insulating layer, a photoconductive layer, an insulating layer and a conductive layer.
As conductive support used in this invention, any supporting material having conductivity may be selected from wide sources. For example, there may be mentioned metallic conductive material such as tin, copper, aluminum and the like and a hygroscopic paper and an aluminum laminated paper.
As insulating support, any supporting material may be used regardless inorganic and organic natures as far as the material is of insulating property. It is not necessary that the insulating support satisfies the conditions as requested for the insulating layer as mentioned above. Naturally the insulating support may be the same material as that of the insulating layer.
When the insulating support is used in a photosensitive member which is used in such a process that the exposure is effected from the support side, it is necessary that the insulating support is transparent to a radiation to which the photoconductive layer is sensitive. Furthermore, the above mentioned materials may be used for a support consisting of an insulating layer laminated with a conductive layer. When transparency is requested, there may be used transparent conductive material such as Nesa glass, polyvinylcarbazole and the like.
in the following, there are illustrated procedures for producing photosensitive members having a photoconductive layer of glassy alloy comprising selenium, antimony and electric property controlling material. The following examples are given for illustration, but by no means for limitation of this invention.
EXAMPLE 1 A mixture of Se of high purity (99.99%), 72 parts by weight, Sb parts by weight, and Te 8 parts is sealed in a vacuum quartz tube, heated and melted at 500C for about 6 hours to form a uniform dispersion system. The resulting melted product is poured into a distilled water to form powder solid matter followed by drying sufficiently. By a vacuum depositing method, the alloy thus obtained is deposited on an aluminum base plate maintained at 60 to 80C to form a glassy thin film, and thus a photoconductive layer of about 60 y. thick is obtained. Then, a polyester film of p. thick is ad hered to the photoconductive layer with epoxy resin to produce a highly sensitive photosensitive plate.
EXAMPLE 2 The procedure of Example 1 is repeated by using a mixture of Se 85 parts by weight, Sb 10 parts by weight and Ge 5 parts by weight in phase of Se, Sb and Te to 20 light of about 10 lu x to form latent images having electrostatic contrast of about 1,000V.
An example of another method is that the secondary corona discharging as mentioned above is effected by A.C. corona discharging. An electrostatic contrast of about 600V is obtained by applying a primary corona discharging of7l(V and a secondary A.C. corona discharging of 5.8KV.
In the former process, a particularly high contrast is obtained, and in the latter process, reproducibility of half tone is excellent.
There are, for example, further processes applicable to the photosensitive member of this invention as shown in the following table. For example, Process A refers to an electrophotographic process comprising the steps, positive primary charging, negative secon dary charging direct exposure, development and radiation (recovering the decay of photosensitive member by irradiating infrared ray etc.), and Process G refers to an electrophotographic process comprising the steps, positive primary charging, A.C. discharging simultaneously with exposure, whole surface irradiation, developing and irradiation.
Primary Secondary A.C. Simultaneous Direct Whole surface Process charging charging discharging exposure exposure irradiation Development Irradiation A 0 0 O B 0 0 0 C 0 0 0 0 D 0 0 0 0 E 0 0 0 0 F 0 0 0 0 G 0 0 O 0 (J H 0 O 0' O 0 with ethyl cellosolve is applied thereto by a flowingdown coating method to form a surface insulating layer of about 10 1. thick.
The photosensitive plates produced as above are used for forming electrostatic images as follows. The 40 polarity of voltage to be applied is selected appropriately in accordance with the type of photoconductivity of the photosensitive plate, for example, when the photoconductive layer is preferably of N-type, the primary charging is positive while when it is of p-type, the primary charging is preferably negative. In the following, the electrostatic image forming procedure is explained, for example, by using a photosensitive plate containing a photoconductive layer of ternary alloy of Se-S- b-Te. The surface of insulating layer of the photosensitive plate is charged to about-2,000V with a corona discharging of 6KV, and exposed at about one lux.sec simultaneously charged by a secondary corona discharging of +6KV and then the whole surface of the photosensitive member is uniformly irradiated with a What is claimed is:
1. An electrophotographic photosensitive member comprising a support layer, a photoconductive layeroverlying the support layer and an insulating overlying the photoconductive layer and at least one of the layers adjacent to the photoconductive layer being transparerit to a radiation to which the photoconductive layer is sensitive, characterized in that the photoconductive layer comprises an amorphous glassy alloy containing about 72 by weight of selenium, about 10 20% by weight of antimony and about 5% by weight of germanium and has a resistivity at dark place of not less than 1X10 ohm-cm.
2. An electrophotographic photosensitive member according to claim 1 wherein the support layer is characterized by having insulating properties.
3. An electrophotographic photosensitive member according to claim ll wherein the support layer is characterized by being electroconductive.
Claims (3)
1. AN ELECTROPHOTOHRAPHIC PHOTOSENITIVE MEMBER COMPRISING A SUPPORT LAYER, A PHOTOCONDUCTIVE LAYER OVERLYING THE SUPPORT LAYER AND AN INSULATING OVERLYING THE PHOTOCONLAYER AND AT LEAST ONE OF THE LAYERS ADJACENT TO THE PHOTOCONDUCTIVE LAYER BEING TRANSPARENT TO A RADIATION TO WHICH THE PHOTOCONDUCTIVE LAYER IS SENSITIVE, CHARACTERIZED IN THAT THE PHOTOCONDUCTIVE LAYER COMPRISES AN AMORPHORUS GLASSY ALLOY CONTAINING ABOUT 72 - 85% BY WEIGHT OF SELENIUM, ABOUT 10 20% BY WEIGHT OF ANTIMONY AND ABOUT 5% BY WEIGHT OF GERMANIUM AND HAS A RESISTIVITY AT DARK PLACE OF NOT LESS THAN 1$1011 OHM-CM.
2. An electrophotographic photosensitive member according to claim 1 wherein the support layer is characterized by having insulating properties.
3. An electrophotographic photosensitive member according to claim 1 wherein the support layer is characterized by being electroconductive.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US414820A US3867143A (en) | 1969-01-17 | 1973-11-12 | Electrophotographic photosensitive material |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP326269A JPS511977B1 (en) | 1969-01-17 | 1969-01-17 | |
| US25619872A | 1972-05-23 | 1972-05-23 | |
| US414820A US3867143A (en) | 1969-01-17 | 1973-11-12 | Electrophotographic photosensitive material |
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| Publication Number | Publication Date |
|---|---|
| US3867143A true US3867143A (en) | 1975-02-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US414820A Expired - Lifetime US3867143A (en) | 1969-01-17 | 1973-11-12 | Electrophotographic photosensitive material |
Country Status (1)
| Country | Link |
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| US (1) | US3867143A (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US3966471A (en) * | 1973-12-25 | 1976-06-29 | Ricoh Co., Ltd. | Electro photosensitive materials with a protective layer |
| US4071648A (en) * | 1974-07-19 | 1978-01-31 | Xonics, Inc. | Electron radiograph receptor |
| US4269919A (en) * | 1976-07-13 | 1981-05-26 | Coulter Systems Corporation | Inorganic photoconductive coating, electrophotographic member and sputtering method of making the same |
| US4297424A (en) * | 1980-03-05 | 1981-10-27 | Xerox Corporation | Overcoated photoreceptor containing gold injecting layer |
| EP0046960A2 (en) * | 1980-08-30 | 1982-03-10 | Hoechst Aktiengesellschaft | Electrophotographic recording material |
| US4330610A (en) * | 1980-03-05 | 1982-05-18 | Xerox Corporation | Method of imaging overcoated photoreceptor containing gold injecting layer |
| US4414179A (en) * | 1981-12-03 | 1983-11-08 | Xerox Corporation | Process for making photoreceptors |
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| US2745327A (en) * | 1952-05-12 | 1956-05-15 | Haloid Co | Electrophotographic process |
| US3427157A (en) * | 1964-12-28 | 1969-02-11 | Xerox Corp | Xerographic process utilizing a photoconductive alloy of thallium in selenium |
| US3490903A (en) * | 1966-07-20 | 1970-01-20 | Xerox Corp | Alloys of antimony and selenium used in photoconductive elements |
| US3524745A (en) * | 1967-01-13 | 1970-08-18 | Xerox Corp | Photoconductive alloy of arsenic,antimony and selenium |
| US3769010A (en) * | 1970-06-20 | 1973-10-30 | Canon Kk | Electrophotographic photosensitive member |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2745327A (en) * | 1952-05-12 | 1956-05-15 | Haloid Co | Electrophotographic process |
| US3427157A (en) * | 1964-12-28 | 1969-02-11 | Xerox Corp | Xerographic process utilizing a photoconductive alloy of thallium in selenium |
| US3490903A (en) * | 1966-07-20 | 1970-01-20 | Xerox Corp | Alloys of antimony and selenium used in photoconductive elements |
| US3524745A (en) * | 1967-01-13 | 1970-08-18 | Xerox Corp | Photoconductive alloy of arsenic,antimony and selenium |
| US3769010A (en) * | 1970-06-20 | 1973-10-30 | Canon Kk | Electrophotographic photosensitive member |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3966471A (en) * | 1973-12-25 | 1976-06-29 | Ricoh Co., Ltd. | Electro photosensitive materials with a protective layer |
| US4071648A (en) * | 1974-07-19 | 1978-01-31 | Xonics, Inc. | Electron radiograph receptor |
| US4269919A (en) * | 1976-07-13 | 1981-05-26 | Coulter Systems Corporation | Inorganic photoconductive coating, electrophotographic member and sputtering method of making the same |
| US4297424A (en) * | 1980-03-05 | 1981-10-27 | Xerox Corporation | Overcoated photoreceptor containing gold injecting layer |
| US4330610A (en) * | 1980-03-05 | 1982-05-18 | Xerox Corporation | Method of imaging overcoated photoreceptor containing gold injecting layer |
| EP0046960A2 (en) * | 1980-08-30 | 1982-03-10 | Hoechst Aktiengesellschaft | Electrophotographic recording material |
| EP0046960A3 (en) * | 1980-08-30 | 1982-08-04 | Hoechst Aktiengesellschaft | Electrophotographic recording material |
| US4414179A (en) * | 1981-12-03 | 1983-11-08 | Xerox Corporation | Process for making photoreceptors |
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