US3780288A - Apparatus for minimizing image smear due to ion caused undercutting - Google Patents

Apparatus for minimizing image smear due to ion caused undercutting Download PDF

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Publication number
US3780288A
US3780288A US00159904A US3780288DA US3780288A US 3780288 A US3780288 A US 3780288A US 00159904 A US00159904 A US 00159904A US 3780288D A US3780288D A US 3780288DA US 3780288 A US3780288 A US 3780288A
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US
United States
Prior art keywords
layer
cassette
conductive material
photoconductor
capacitor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00159904A
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English (en)
Inventor
V Dryden
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Xerox Corp
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Xerox Corp
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Filing date
Publication date
Application filed by Xerox Corp filed Critical Xerox Corp
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Publication of US3780288A publication Critical patent/US3780288A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/054—Apparatus for electrographic processes using a charge pattern using X-rays, e.g. electroradiography

Definitions

  • An electric field perpendicular to the surface of the photoconductor 12 is generated in the region between the xerographic plate and conducting surface 22 due to the initial charge which is utilized to sensitize the surface of photoconductor 12.
  • the electric field in this region is further enhanced by placing an electrostatic charge on conducting surfaces and 22.
  • Dielectric material 18 and conducting surfaces 20 and 22 form a distributed capacitor which is charged by connecting voltage source 28 across the conducting surfaces.
  • Voltage source 28 is illustrated in a manner to indicate that after it charges conducting surfaces 20 and 22, it is removed from contacts 25 and 27 prior to the exposure of object 26 by the X-ray source 29.
  • dielectric layer 18 when formed of Mylar, is about 0.003 inches whereas the conducting surfaces 20 and 22, when formed of aluminum, are approximately 0.0005 inches thick.
  • resistor 24 is typically 10 ohms.
  • DC. voltage source 28 is connected across conducting plates 20 and 22 through resistor 24 and applies a potential thereacross in the range from about 400 volts to about l,600 volts, depending on the initial charge placed on photo conductive layer 12, and of a polarity as shown that a negative charge is formed on conducting surface 22. It is assumed that the surface of photoconductor 12 has initially been charged to a positive potential. Object 26 is then exposed to penetrating radiation generated by X-ray source 29. The voltage source 28 may then be disconnected from conducting plates 20 and 22 or, alternatively, may be disconnected prior to exposure.
  • the electric field perpendicular to the surface of photoconductor 12 tends to confine the air ions to the immediate region where they are generated. Ions charged to the same polarity as the polarity of the electrostatic charge on the photoconductor surface are at tracted to the conducting surface 22 while the ions charged to a polarity opposite to that of the electrostatic charge on the surface of the photoconductor tend to further discharge the photoconductor 12 in the same pattern as the X-rays which expose the photoconductor 12. Consequently, the image of the object being examined is improved due to the presence of the electric field generated by the capacitor 16 which is maintained even though the plate is discharged by the exposure.
  • the electric field tends to maintain ions in the position over the plate where they were formed (unless they have excess lateral energy from their formation). Negative ions are forced toward the plate contributing constructively to the exposure while positive ions are forced away from the plate.
  • the distributed (sheet) capacitor 16 does not need a permanent charging source and may be charged, as set forth hereinabove, just before exposure. Experience with modest energy X-ray (in the range from about 25 KVP to about 45 KVP) exposures shows that capacitor 16 will maintain its charge for at least exposures.
  • capacitor 16 is chosen to be transparent to X-ray radiation, the X-ray radiation does not effect the charge thereon.
  • Resistor 24 is not necessary for the operation of the present invention. However, resistor 24 acts to prevent the thin aluminum surfaces from burning off the electrodes 20 and 22 around the contact area (illustrated in FIGS. 2-5 hereinbelow) during charging of capacitor 16 or if conducting surface 22 is accidentally brought into contact with photoconductive layer 12. In addition, resistor 24 protects against shock hazard when used, for example, in the cassette illustrated in FIGS. 2-5. In lieu of resistor 24, substrate 14 may be connected directly to conducting surface 20 or via a resistor of smaller resistance value.
  • FIG. 1 b illustrates an alternate embodiment which utilizes a lumped capacitor 16 to couple metal electrode 22' to substrate 14 via resistor 24.
  • the operation of the invention described in this embodiment is identical to that described with reference to FIG. 1a.
  • the physical size of capacitor 16 required to produce the desired results makes the embodiment of FIG. 1a, which utilizes distributed capacitor 16, the preferred embodiment for the purposes of the present invention.
  • FIG. 3 is a front elevation of the cassette 30 showing the substrate of photoreceptor plate 10 connected to conducting surface 20 via conductor spring 34, spring contact 36 and deposited resistor 24. Also shown are guide rails 35 for supporting the photoreceptor plate within the cassette.
  • the distributed capacitor 16 is placed inside the eassette lid and held thereto by a suitable adhesive with the top conducting surface electrically connected to the metallic substrate of plate 10 as shown.
  • Apparatus for minimizing image smear of an image formed by exposing an object to penetrating radiation, the penetrating radiation transmitted by said object forming a latent electrostatic image on the surface of an initially charged photoconductor layer positioned adjacent thereto, said photoconductor layer overlying a conductive substrate comprising:
  • a distributed capacitor spaced apart from and substantially parallel to the surface of said photoconductor, said distributed capacitor comprising an insulating layer sandwiched between layers of conductive material,
  • a cassette for enclosing in a light-tight environment a photoconductor layer formed on a conductive substrate, said photoconductor layer having a latent electrostatic charge formed thereon, said cassette including lid and bottom portions, said photoconductor layer being supported in the bottom portion comprismg:
  • a distributed capacitor spaced apart from and substantially parallel to the surface of said photoconductor layer, said distributed capacitor comprising an insulating layer sandwiched between layers of conductive material and attached to the inside of said lid, and
  • the cassette as defined in claim 4 further including means within said cassette for electrically coupling a source of potential applied thereto across said layers of conductive material.
  • a cassette having lid and bottom portions comprisa distributed capacitor supported within said lid portion and comprising an insulating layer sandwiched between layers of conductive material

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  • Health & Medical Sciences (AREA)
  • Pathology (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Radiation (AREA)
  • Combination Of More Than One Step In Electrophotography (AREA)
  • Radiography Using Non-Light Waves (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
  • Conversion Of X-Rays Into Visible Images (AREA)
US00159904A 1971-07-06 1971-07-06 Apparatus for minimizing image smear due to ion caused undercutting Expired - Lifetime US3780288A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US15990471A 1971-07-06 1971-07-06

Publications (1)

Publication Number Publication Date
US3780288A true US3780288A (en) 1973-12-18

Family

ID=22574607

Family Applications (1)

Application Number Title Priority Date Filing Date
US00159904A Expired - Lifetime US3780288A (en) 1971-07-06 1971-07-06 Apparatus for minimizing image smear due to ion caused undercutting

Country Status (10)

Country Link
US (1) US3780288A (enExample)
JP (1) JPS52106744A (enExample)
AR (1) AR195379A1 (enExample)
BE (1) BE785910A (enExample)
BR (1) BR7204467D0 (enExample)
CA (1) CA999041A (enExample)
FR (1) FR2145169A5 (enExample)
GB (1) GB1351915A (enExample)
IT (1) IT962369B (enExample)
NL (1) NL7206563A (enExample)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3879610A (en) * 1973-08-27 1975-04-22 Diagnostic Instr Inc Ionographic exposure method, apparatus
US3898722A (en) * 1973-04-02 1975-08-12 Xerox Corp Process for forming an electrode
US3949222A (en) * 1974-11-01 1976-04-06 Xonics, Inc. Method and apparatus for reducing the density of background areas without affecting the density of picture areas in an electronradiograph
US4041312A (en) * 1975-04-23 1977-08-09 A. B. Dick/Scott Apparatus for electrostatically charging an electrophotographic film
WO1996021887A3 (en) * 1995-01-13 1996-09-12 Minnesota Mining And Manufacturing Company Detector plate for use in imaging systems

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2802948A (en) * 1954-09-22 1957-08-13 Haloid Co Prevention of ion-caused undercutting in xeroradiography

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2802948A (en) * 1954-09-22 1957-08-13 Haloid Co Prevention of ion-caused undercutting in xeroradiography

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3898722A (en) * 1973-04-02 1975-08-12 Xerox Corp Process for forming an electrode
US3879610A (en) * 1973-08-27 1975-04-22 Diagnostic Instr Inc Ionographic exposure method, apparatus
US3949222A (en) * 1974-11-01 1976-04-06 Xonics, Inc. Method and apparatus for reducing the density of background areas without affecting the density of picture areas in an electronradiograph
US4041312A (en) * 1975-04-23 1977-08-09 A. B. Dick/Scott Apparatus for electrostatically charging an electrophotographic film
WO1996021887A3 (en) * 1995-01-13 1996-09-12 Minnesota Mining And Manufacturing Company Detector plate for use in imaging systems
US5637882A (en) * 1995-01-13 1997-06-10 Minnesota Mining And Manufacturing Company Detector plate for use in imaging systems

Also Published As

Publication number Publication date
DE2225767A1 (de) 1973-01-18
CA999041A (en) 1976-10-26
DE2225767B2 (de) 1977-03-31
NL7206563A (enExample) 1973-01-09
GB1351915A (en) 1974-05-15
BR7204467D0 (pt) 1973-06-05
BE785910A (fr) 1973-01-08
AR195379A1 (es) 1973-10-08
JPS52106744A (en) 1977-09-07
IT962369B (it) 1973-12-20
FR2145169A5 (enExample) 1973-02-16

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