EP0000045B1 - Elektrofotografische Kopiervorrichtung mit einer Einrichtung zum Löschen eines elektrostatischen Ladungsbildes - Google Patents

Elektrofotografische Kopiervorrichtung mit einer Einrichtung zum Löschen eines elektrostatischen Ladungsbildes Download PDF

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Publication number
EP0000045B1
EP0000045B1 EP78100083A EP78100083A EP0000045B1 EP 0000045 B1 EP0000045 B1 EP 0000045B1 EP 78100083 A EP78100083 A EP 78100083A EP 78100083 A EP78100083 A EP 78100083A EP 0000045 B1 EP0000045 B1 EP 0000045B1
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EP
European Patent Office
Prior art keywords
radiation
spectral
spectral region
maximum
light
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
Application number
EP78100083A
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German (de)
English (en)
French (fr)
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EP0000045A1 (de
Inventor
Eberhard Bayer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
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Siemens AG
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Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Publication of EP0000045A1 publication Critical patent/EP0000045A1/de
Application granted granted Critical
Publication of EP0000045B1 publication Critical patent/EP0000045B1/de
Expired 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
    • G03G21/00—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge
    • G03G21/06—Eliminating residual charges from a reusable imaging member
    • G03G21/08—Eliminating residual charges from a reusable imaging member using optical radiation

Definitions

  • the invention relates to an electrophotographic copying device, as specified in the preamble of claim 1.
  • a copying device is known from DE-OS 26 46 150, in which two individual light sources with radiation of the same spectral distribution are provided for quenching the charge of the electrophotographic layer.
  • DE-OS Relating to the cyclical process of xerography with erasing-charge spraying-scanning-toner-sputtering-printing, the device known from DE-OS uses a light source as usual for complete erasing after printing. However, the second light source for partially erasing the charge is interposed between toner sputtering and printing.
  • the carrier of the layer used is transparent to radiation and this second light source is arranged on the back of the carrier, because in this state one side of the layer is still covered with the toner of the image which has not yet been printed .
  • the spectral distribution of these two light sources it is stipulated that at least 25% of the radiation intensity falls in a wavelength range in which the optical density of the image carrier is at least 50% of the highest optical density of the image carrier, here under "optical density" not the refractive index of the Layer material, but a measure of the spectral radiation absorption in the layer is to be understood.
  • DE-OS 26 46 150 in addition to using a second light source for partially extinguishing the charge even before printing in the case of a radiation carrier which is necessarily permeable to radiation, is intended to reduce the symptoms of fatigue which are noticeable as ghosting (page 12, paragraph 1) do.
  • a reference contained in the DE-OS to red extinguishing light (p. 22) instead of green or white extinguishing light (page 18, paragraph 3) relates to its use with organic photoconductors with absorption maxima, which are spectral with light of the wavelength range of this red light match (page 23 paragraph 2 and page 15 paragraph 1).
  • Electrophotographic copying devices are known from the prior art, in which an electrostatic charge image is generated in a layer of a photoconductive material such as arsenic-selenium.
  • the layer is charged by means of a corona discharge.
  • An inscribed charge image is usually deleted with light of a spectral range of maximum photoconductivity generation.
  • spectral range i.e. a spectral range with which the greatest increase in conductivity compared to the dark conductivity is achieved in comparison with other spectral ranges under otherwise identical radiation conditions.
  • this spectral range lies in the green light range at approximately 500 nm.
  • the charge image is generally written in with light of the same spectral range.
  • FIG. 1 schematically shows the result to be achieved with the invention.
  • the diagram shows the charging surface potential over the number of successive charges with a sequence of points 1. For comparison, the case is entered in this diagram in which the extinguishing with light of an incandescent lamp with filtering as used in the prior art has been carried out.
  • sequence 2 consisting of crosses is entered. Each point or cross corresponds to a potential measurement after charging a drum, as is customary in such copying devices, on which the photoconductive layer of As-Se is located. No write exposure is involved in these rounds of episodes 1 and 2. From the diagram or from the difference between sequence 1 and sequence 2, one can clearly see this one stabilizing effect which is achieved with the measure according to the invention.
  • Circles of a sequence 3 denote the potential of the photoconductive layer which is suitable for one of the revolutions of the drum, i.e. for one of the successive copying processes, in the case of write exposure with such light, which according to the known prior art - see e.g. U.S. Patent 3,511 1,649 - leads to severe potential fatigue.
  • the representation is normalized to these potential values 3 with respect to the ordinate.
  • the advantage described above also has the further advantage that, after a write exposure indicated with sequence 3 of the circles, subsequent cycles of a sequence 4 (again shown with circles) in which no more write exposure is provided, the same potential value occurs immediately as in episode 1 and remains the same for the other cycles.
  • the point sequences 1 and 4 thus together represent a constant charging of the surface potential independent of write exposure processes, which is achieved with the measures according to the invention for all cycles in which there is no write exposure (regardless of the number of previous such cycles).
  • FIG. 1 furthermore shows which potential values of the surface potential occur on the other hand if, for example, a filtered incandescent lamp is used in accordance with the known prior art.
  • Sequence 5 which is marked by triangles, indicates the sequence of charges of the layer occurring from cycle to cycle, counted after the last write exposure, in the event that the measures according to the invention are not applied.
  • the invention therefore provides for the light used for the extinction to be composed of two spectral ranges.
  • One spectral range is approximately ⁇ 10% around a radiation wavelength at which maximum photoconductivity generation can be achieved in the photoconductive material.
  • this value of the maximum 12 is 500 nm.
  • the width indicated with + 10% characterizes the spectral range in which light is equivalent in terms of the photoconductivity generation in the respective material.
  • the integral of the radiation energy over this range is effective in the photoconductive material for photoconductivity generation.
  • the other spectral range in which the wavelength for light of the maximum of the product of photoconductivity generation and penetration depth lies.
  • the penetration depth is the distance from the surface of the layer at which the intensity of the radiation incident perpendicularly to the surface has dropped to 1 / e.
  • the effect of the light 13, for the wavelength of which the product of photoconductivity generation and penetration depth is maximum, corresponds physically to an amplification effect due to changed space charge conditions, which produce a higher photoconductivity for light of all wavelength ranges which are shorter-wavelength than the light of this spectral range 13.
  • the light of the two spectral ranges provided according to the invention can thus be light from a single radiation source which is provided, for example, with appropriate filters.
  • this dimensioning according to the invention can also be implemented with the aid of two light sources, one of which emits white light and the other light practically only of the spectral range of the maximum photoconductivity generation 11, in the case of the As Z Se 3 green light.
  • the light of the area of the maximum product can therefore be part of this white light.
  • the spectral range of maximum photoconductivity generation is designated with 11, with 12 indicating the wavelength of the maximum plotted on the abscissa.
  • the range 11 around this wavelength value 12 is defined as ⁇ 10%. It should be pointed out that the specification ⁇ 10% is an approximate specification which is dependent on the respective photoconductive material anyway and is essentially intended to give the person skilled in the art an indication.
  • the range of the wavelengths of the maximum of the product of photoconductivity generation and penetration depth is illustrated in a corresponding manner by 13. This lies around a wavelength 14.
  • FIG. 2 An example of the energy ratio of the radiations of these regions to one another can be seen from the illustration in FIG. 2.
  • the approximate position of the absorption curve of a photoconductive material as a function of the wavelength is plotted in the diagram in FIG. 2.
  • the position of the areas provided according to the invention in relation to this absorption curve can be clearly seen from this illustration.
  • the line 16 shown in broken lines in FIG. 2 indicates additional radiation, which may be present, for example, and which lies outside the spectral ranges mentioned. Spectral components of this radiation that fall into the respective spectral ranges 11 and 13 are to be included in the energy values of the ranges 11 and 13, respectively.
  • Fig. 3 shows schematically a known copying device in which the invention is implemented.
  • 21 is a drum on which the photosensitive layer 211 is located.
  • a device for a corona discharge is indicated.
  • 24 denotes a device for writing exposure in which there is a light source 241 for, for example, red light.
  • a printing device for making the electrostatic copies is indicated.
  • 26 a device is designated in which the Erfin is specifically realized.
  • the light source 261 located in this device 26 can, for example using a filter 262, deliver both the light of the spectral range of maximum photoconductivity generation and the light of the spectral range of the maximum of the specified product.
  • a second device 26 'with a light source 261 is included, which generates the required light of the other spectral range.
  • a second device 26 'with a light source 261 is included, which generates the required light of the other spectral range.
  • the light of the two spectral ranges reach the surface of the drum 21 or the layer 211 simultaneously. Rather, it is also possible to carry out the irradiation of the light of the one spectral range in time after the irradiation of the light of the other spectral range (and vice versa).
  • these two exposures are carried out in succession (not separated from one another, for example by a corona charge or a copying process), namely between the printing process with the device 25 and the (re) charging of the corona. Facility 23.
  • the contrast potential 5 minus 3 (FIG. 1) changes by 50% until its stabilized end value is set.
  • A results in a corona current density of 13,4.10-4- to a charge potential of 700 V.
  • changes m2 the contrast potential minus 4 3 (Fig. 1) by less than 3% and for setting its stabilized final value, what the desired Influence of the proposed device 26 illustrates.
  • the erasure exposure according to the invention which can also be addressed as pre-exposure before the corona charge, results in an increased photosensitivity of the material of the layer for the write exposure with a light long-wave spectral range.
  • "Long-wave” is to be understood as a wavelength range in which the light energy essentially corresponds to the band edge of the respective photoconductive material. For As 2 Se 3 , this is a range from approximately 550 to 650 nm. Previously, registered letters with such a long wavelength had to be ruled out in practice, as can be seen, for example, from US Pat.

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  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Discharging, Photosensitive Material Shape In Electrophotography (AREA)
  • Photoreceptors In Electrophotography (AREA)
  • Exposure Or Original Feeding In Electrophotography (AREA)
  • Light Sources And Details Of Projection-Printing Devices (AREA)
EP78100083A 1977-06-14 1978-06-02 Elektrofotografische Kopiervorrichtung mit einer Einrichtung zum Löschen eines elektrostatischen Ladungsbildes Expired EP0000045B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2726805A DE2726805C3 (de) 1977-06-14 1977-06-14 Elektrofotografische Kopiervorrichtung mit einer Einrichtung zum Loschen eines elektrostatischen Ladungsbildes
DE2726805 1977-06-14

Publications (2)

Publication Number Publication Date
EP0000045A1 EP0000045A1 (de) 1978-12-20
EP0000045B1 true EP0000045B1 (de) 1981-10-21

Family

ID=6011507

Family Applications (1)

Application Number Title Priority Date Filing Date
EP78100083A Expired EP0000045B1 (de) 1977-06-14 1978-06-02 Elektrofotografische Kopiervorrichtung mit einer Einrichtung zum Löschen eines elektrostatischen Ladungsbildes

Country Status (7)

Country Link
US (1) US4170413A (ja)
EP (1) EP0000045B1 (ja)
JP (1) JPS547347A (ja)
AT (1) AT359827B (ja)
CH (1) CH622628A5 (ja)
DE (1) DE2726805C3 (ja)
IT (1) IT1096641B (ja)

Families Citing this family (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6027026B2 (ja) * 1977-06-17 1985-06-26 キヤノン株式会社 電子写真方法及び装置
JPS5557875A (en) * 1978-06-24 1980-04-30 Mita Ind Co Ltd Transfer type electrostatic copying machine
JPS55101981A (en) * 1979-01-31 1980-08-04 Ricoh Co Ltd Electrophotographic copying method
JPS5624383A (en) * 1979-08-02 1981-03-07 Minolta Camera Co Ltd Light erasing device in transfer type copying machine
JPS57212458A (en) * 1981-06-24 1982-12-27 Ricoh Co Ltd Electrophotographic copying method
JPS587649A (ja) * 1981-07-08 1983-01-17 Ricoh Co Ltd 電子写真複写方法及びその装置
JPS58114082A (ja) * 1981-12-28 1983-07-07 Ricoh Co Ltd 静電記録方法
JPS58137873A (ja) * 1982-02-10 1983-08-16 Ricoh Co Ltd 感光体除電方法
JPS6014255A (ja) * 1983-07-05 1985-01-24 Toshiba Corp 画像形成装置
JPS6014254A (ja) * 1983-07-05 1985-01-24 Toshiba Corp 電子写真装置
JPS6082669U (ja) * 1983-11-10 1985-06-07 株式会社リコー 感光体光除電器
JPS6197668A (ja) * 1984-10-17 1986-05-16 Sharp Corp 電子写真感光体の帯電電位安定化装置
DE3536836A1 (de) * 1984-10-17 1986-04-17 Sharp K.K., Osaka Entladevorrichtung fuer ein kopiergeraet
JPS6197667A (ja) * 1984-10-17 1986-05-16 Sharp Corp 電子写真感光体の帯電電位安定化方法
JPS6197683A (ja) * 1984-10-17 1986-05-16 Sharp Corp 電子写真感光体の帯電電位安定化方法
JPS6197681A (ja) * 1984-10-17 1986-05-16 Sharp Corp 電子写真感光体の光疲労防止方法
DE3901496A1 (de) * 1988-01-21 1989-08-03 Fuji Electric Co Ltd Elektrofotografischer drucker
US5606398A (en) * 1995-04-28 1997-02-25 Minnesota Mining And Manufacturing Company Reduction of residual potential and ghosting in a photoconductor

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3481669A (en) * 1965-03-01 1969-12-02 Xerox Corp Photo-charging of xerographic plates
US3666364A (en) * 1965-12-01 1972-05-30 Canon Kk Electrophotographic apparatus
US3511649A (en) * 1966-05-02 1970-05-12 Xerox Corp Process of reducing fatigue in photoconductive glasses
US3615395A (en) * 1966-09-28 1971-10-26 Canon Camera Co Electrostatic and electrophotographic variable contrast image-forming methods
JPS494337B1 (ja) * 1969-07-28 1974-01-31
JPS5025233A (ja) * 1972-09-20 1975-03-17
US3930853A (en) * 1973-12-06 1976-01-06 Xerox Corporation Accelerating aging method for selenium-arsenic photoconductors
US3963488A (en) * 1974-09-03 1976-06-15 Gaf Corporation Contrast of electrostatic latent images with a light flooding step
US4035750A (en) * 1975-10-14 1977-07-12 Eastman Kodak Company Electrophotographic apparatus having improved photoconductor regenerative structure and procedure

Also Published As

Publication number Publication date
ATA408778A (de) 1980-04-15
JPH0514277B2 (ja) 1993-02-24
DE2726805C3 (de) 1981-01-22
DE2726805B2 (de) 1980-05-08
DE2726805A1 (de) 1978-12-21
JPS547347A (en) 1979-01-20
CH622628A5 (ja) 1981-04-15
US4170413A (en) 1979-10-09
IT7824439A0 (it) 1978-06-12
EP0000045A1 (de) 1978-12-20
AT359827B (de) 1980-12-10
IT1096641B (it) 1985-08-26

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