US3871878A - Electrophotographic or xerographic method for treating a picture image - Google Patents

Electrophotographic or xerographic method for treating a picture image Download PDF

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Publication number
US3871878A
US3871878A US356698A US35669873A US3871878A US 3871878 A US3871878 A US 3871878A US 356698 A US356698 A US 356698A US 35669873 A US35669873 A US 35669873A US 3871878 A US3871878 A US 3871878A
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image
polarity
electrostatic latent
picture
primary
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Expired - Lifetime
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US356698A
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English (en)
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Masayuki Mino
Kuniki Seino
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Minolta Co Ltd
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Minolta Co Ltd
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G13/00—Electrographic processes using a charge pattern
    • G03G13/22—Processes involving a combination of more than one step according to groups G03G13/02 - G03G13/20

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  • An electrophotographic method for treating a picture includes the steps of charging a substrate at a first polarity, projecting an image of an original on the charged substrate to produce an electrostatic latent image, imparting a uniform charge of opposite polarity to the image bearing substrate to reverse the polarity of the electrostatic latent primary image and projecting a secondary image of an original on the reversed polarity image bearing substrate to produce a resultant image which is then developed.
  • the primary and secondary images may be of different originals to produce resultant images of additive or reductive portions permitting the simple examination of the differences between the originals, the images may be offset images of the same original to provide relief pictures, or they may be focussed and defocussed images of the same original to emphasize fine details.
  • the charge reversal is obtained by exposing the primary image beating substrate to a constant current corona or to a uniformly charged superimposed dielectric member.
  • the present invention relates generally to a method for treating a picture image by electrophotography, and
  • the first above indicated method fails to produce a picture image of high resolving-power, because of the scanning interval and the characteristics of the picture tube, and in addition the apparatus used in this method is costly; in the second or optical treatment method, because of the nature of the light wave, an accuracy of the respective components of the optical system is required at least commensurate with the order of the wave length in every unit of wave length, and this results in great difficulty in obtaining a suitable picture image; and in the last or silver-salt photographic image treatment method, it is very difficult to provide the required gradation and density, and in addition, the procedures are troublesome because it is necessary to form a negative image and to adjust the position of the picture image for overlapping two images one upon another.
  • Another object of the present invention is to provide an improved method for producing a composite image by electrophotography or xerography.
  • Still another object of the present invention is to provide an improved method for producing a composite image which is a function of a plurality of unit images.
  • a further object of the present invention is to provide an improved electrophotographic method for producing a resultant image which is the variance or difference between a pair of images or originals.
  • Still a further object of the present invention is to provide an improved electrophotographic method for forming relief images.
  • Another object of the present invention is to provide an improved method of the above nature characterized by its simplicity, low cost, inexpensive equipment, great versatility and which is capable of producing images having fine detail and varied characteristics.
  • FIG. 1 is a block diagram representing the basic process of the present invention
  • FIGS. 2(a) to 2(c) are front elevational views illustrating the reverse changing of a latent electrostatic image
  • FIGS. 3(a) and 3(b) are plan views of a pair of originals which are to be treated by the present method
  • FIGS. 4(a) to 4(a) are plan views illustrating the successive steps in the production of a first composite image from the originals shown in FIGS. 3(a) and 3(b);
  • FIGS. 5(a) to 5(0) are views similar to FIGS. 4(a) to 4(b) showing the production of another composite image
  • FIGS. 6(a) to 6(a') are plan views illustrating a pair of originals and a pair of composite images produced from the originals in opposite sequences;
  • FIG. 7 is a plan view of another original
  • FIG. 8 is a plan view of a relief image thereof produced by the present method.
  • FIG. 9 is a plan view of an image emphasizing fine detail produced by the present method.
  • a photosensitive member or substrate 1 for example, a photosensitive paper, or a photosensitive plate is employed in the present method and is of the type which may be charged to a positive or negative polarity and in which the charge is dissipated where exposed to incident light.
  • the photosensitive members employable in the present mehtod are an organic photosemiconductor, a zinc-oxide resin bonded material of a nature for use with positive and negative polarities, and a polyvinyl carbazol-selenium laminate.
  • An electrostatic latent image of a positive or negative polarity which corresponds to a given picture image depending upon the desired modification purpose .is formed by a known method on the surface of photosensitive member 1 chargeable to a positive or negative polarity. This is the process step II of FIG.
  • the photosensitive member is uniformly charged to a positive or negative polarity by, for example, a corona discharge device, after which a given picture image for the desired purpose is irradiated onto the charged photosensitive member.
  • a corona discharge device After the process, electrostatic charge on a portion corresponding to a light portion of the picture image is attenuated or dissipated according to the brightness thereof, whereby an electrostatic latent image corresponding to the original picture image is formed on the photosensitive member.
  • the electrostatic latent image thus formed by the preceding process step is reversed in the succeeding proces step in such a way that the portion correspondirig to the light portion of picture image on the photosensitive member is charged with an opposite polarity to that of the preceding process step and the charges on the portion corresponding to a dark portion of picture image becomes neutralized, the process step III of FIG. 1.
  • This is effected by imparting a uniform charging of an opposite polarity to the surface of the photosensitive member by means of an opposite polar cross electrification system or an opposite polarity electrostatic charge transfer system.
  • an opposite polar cross electrification system or an opposite polarity electrostatic charge transfer system For producing a picture image of high resolving-power, it is necessary, in the present process, to prevent the collapse of the electrostatic latent image and the lowering of the electrostatic contrast.
  • the capacitance of the dielectric member should be considerably smaller than that of the photosensitive member.
  • the system using the dielectric member is advantageous in that the reversed electrostatic latent image is excellent, compared with that by the opposite polarity corona electrification system, and there is no need of using a constant current corona discharge device.
  • the reversed electrostatic latent image is again subjected to irradiation.
  • This is effected by irradiating a given or secondary picture image according to the desired purpose onto the initial picture image on the photosensitive member, whereby the electrostatic charge existing on that portion corresponding to the light areas of the picture image decays in accordance with the brightness of the secondary picture image, hence the electrostatic charge existing on a portion corresponding to a dark area of the seconary picture'image remains on the photosensitive member.
  • the initial or primary picture image of electrostatic latent primary image is effected by irradiating a given or secondary picture image according to the desired purpose onto the initial picture image on the photosensitive member, whereby the electrostatic charge existing on that portion corresponding to the light areas of the picture image decays in accordance with the brightness of the secondary picture image, hence the electrostatic charge existing on a portion corresponding to a dark area of the seconary picture'image remains on the photosensitive member.
  • the initial or primary picture image of electrostatic latent primary image is
  • an electrostatic latent image modified or Jerusalem.
  • the electrostatic latent image thus formed is developed into a visible image in any suitable manner, thereby permitting the observation of the resultant or composite visible image.
  • APPLICATION I This is an example of a method of producing a composite image which is the variant portion between two picture images, such as an additive portion or a reductive portion.
  • FIG. 3 there are employed a picture image bearing original image A, and a picture image bearing original image B having a common portion, an additive portion and a reductive portion in relation to the original image A, in order to produce a variant portion or picture image between both original picture images.
  • the picture image irradiation is effected, the original picture image A, is projected on the photosensitive member which has been charged with, for example, a positive polarity in the process step II,, for forming a primary electrostatic latent image of the original picture image A, as shown in FIG. 4 (0).
  • the electrostatic latent image is reversed in the process step III as shown in FIG. 4 (b), after which the originalor secondary picture image B is projected on the primary image by irradiation process step IV, whereby a composite or resultant image containing only the electrostatic latent image of the additive portion of the image is produced.
  • the resultant or composite electrostatic latent image is subjected to development into a visible image and the desired visible image is thus obtained.
  • An electrostatic latent primary image of the original picture image B is firstly formed as shown in FIG. 5 (a), then reversed by process step III as shown in 5 (b), and followed by projection of the secondary defining original picture image A by process step IV, thereby obtaining a composite electrostatic latent image of only the reductive portion between both original picture images, as shown in 5 (c).
  • the present mehtod is applied to the production of a variant portion between two images
  • a change between two phenomena or matters which occurs in an interval of time can be effectively determined by observing the additive portion or the reductive portion between the two original picture images.
  • the above method is highly efficacious when applied to observing the change in the condition of a disease by the X-ray photograph, since the variant portion is easily produced by irradiating or projecting image from two sheets of X-ray photograph in the process steps II and APPLICATION II Reliefs may be produced by the present method in the following manner.
  • the picture image irradiation is effected by shifting the position of a picture image, using a single original image to sequentially apply the primary and secondary image irradiation.
  • the picture image of an original is projected
  • the position of the picture image is shifted for the projection of the said picture image, thereby obtaining a relief picture image.
  • the shift of the position of the picture image may be effected at the stage of the first picture image irradiation. In the present application, only the single sheet of original is used, hence there is no need for aligning the picture images.
  • APPLICATION III This application is for the production of the minute and fine portions of a picture image.
  • a single sheet (an identical one) of original is used, and the picture image is subject to irradiation or projection in an unfocussed condition.
  • the picture image of the original is projected in slightly unfocussed condition
  • the subsequent picture image irradiation process step IV the image irradiation is effected in a sharply focussed condition, thereby providing a formation of a minute and fine portion of the original picture image.
  • the gradation and density of an image to be produced are adjustable by adjusting an amount of electrostatic charge on both an electrostatic latent image formed in process step II and a reversed electrostatic latent image in process step III and the amount of exposure in the picture image irradiation process. This mechanism will be referred to hereafter.
  • the relation of the amount of electrified electrostatic charge with an amount of exposure is adjustable depending upon the kind of photosensitive material of the photosensitive member used, the wave length and charge polarity, and the like.
  • EXAMPLE I This example is an illustration of the opposite polarity charging by a corona discharge.
  • the photosensitive member or substrate employed was a Fax paper (ZrO sensitive paper) manufactured by Crown'Zenovac Company which can be charged to a negative or positive polarity.
  • the photosensitive substrate maintained stationary on a metallic plate, was subjected to two charging scans at an applied voltage of about 6.5KV and a charging speed of 6cm/second to be uniformly charged to a surface potential of about 650V. Subsequently, the slide film bearing the positive image as shown in FIG. 6 (a) was projected on the charged substrate by a projector using a tungsten lamp of 150W at about 210 lux.sec. for
  • the electrostatic latent image thus formed was again subjected to scanning for charging by a corotoron charger at an applied voltage of about -4.8KV and at a charging speed of 9cm/second, with the result that the surface potential was decreased to 0V or thereabout at the dark areas and to 200V at the light areas, whereby the electrostatic latent image is inverted.
  • the slide film bearing the positive image as shown in FIG. 6 (b) was projected onto the primary image carrying substrate by the projector having a tungsten lamp of 150W.
  • the films were set so as to align the common portions of the positive picture images in FIGS. 6 (a) and 6 (b) with each other.
  • the, photosensitive substrate was subjected to a wet development by a positive toner, thereby obtaining the image of pattern as shown in FIG. 6 (c).
  • FIG. 6 (b) in relation to FIG. 6 (a) is produced in the composite or resultant picture.
  • EXAMPLE II This example demonstrates the reversal of the primary image polarity making use of a charge transfer procedure.
  • the identical image and identical photosensitivepaper to those of Example I were used.
  • the slide film bearing the positive image as shown in FIG. 6 (b) was subjected to irradiation in the same condition as in Example I, for forming an electrostatic primary latent image corresponding to FIG. 6 (b).
  • a Mylar film of ,u in thickness located on the metallic plate was uniformly charged to a surface potential of about 1,000V by a corotoron charger, after which the metallic base plate carrying the Mylar film and the metallic base plate with the photosensitive paper were brought into registry and were maintained in a short-circuited state to adhere the Mylar film to the photosensitive paper. Then, the Mylar film was carefully separated from the photosensitive paper. Thus, the reversed electrostatic latent image having the light areas at about 200V and the dark areas at about was obtained.
  • Example III This example demonstrates the formation of a relief image.
  • a single original of image bearing slide film was prepared as an original image, as shown in FIG. 7, and the same photosensitive paper as in Example I was used.
  • a uniform charging of a positive polarity was effected in the manner of Example I, after which the image bearing original film was projected under the same condition as in Example I, thereby forming an electrostatic latent image corresponding to the image of FIG. 7.
  • Example II a reversed electrostatic latent image having a light areas charge of about 200V and a dark areas charge of O was obtained. Subsequently, the original film was set in a sligtly shifted position and subjectedv to irradiation under the same condition as in Example I, then followed by the wet development by a positive toner, thereby obtaining the relief image as shown in FIG. 8. In this case, instead of shifting the position of the film, the photosensitive paper may be shifted.
  • EXAMPLE IV This example demonstrates a method for producing the minute and fine portions of a picture image.
  • the same original pattern and the same photosensitive paper as those of Example III were used.
  • the image bearing original film (projecting portion) was shifted slightly upwardly into a defocussed position.
  • the original film thus set in the defoccused condition was subjected to irradiation of about 210 lux.second for dissipating the illuminated areas to a potential of about 50V.
  • the potential in the dark areas decayed by about 50V.
  • the electrostatic latent image thus formed was reversed through the same procedures with those of Example III into an electrostatic latent image having the light portion of about 70V and the dark portion of O,- or thereabout.
  • the picture image bearing original film was shifted to the focussed position, then subjected to irradiation under the same condition as in Example I, and followed by the wet development by the positive toner.
  • the minute portion of the original picture image was produced, as shown in FIG. 9.
  • the improvement in a picture image as well as in judgement examination and comparison of things and events can be achieved by treating a picture image by a simple process, including the steps of the formation of an electrostatic latent image, a treatment for inverting the electrostatic latent image and the steps of subjecting the inverted electrostatic latent image to irradiation, all of which are performed of electrophotographic techniques. Accordingly, the technical drawbacks of earlier methods are mostly overcome and in addition, charge application is effected with great ease. Another advantage is in that in practice, there is no need for preparing an original bearing a negative image, and in the process for producing relief images or minute portions of an original picture image, neither process for overlapping two picture images nor a process for setting two piture images in alignment is needed.
  • the gradation and density of a picture image to be produced are adjustable readily by adjusting the amount of electrostatic charge and the amount of exposure.
  • the method of producing a composite picture comprising the steps of producing a reversed electrostatic latent primary image on a substrate by forming said primary image at a predetermined polarity on said substrate and thereafter reversing the polarity of said first latent image, directing on said latent image carry ing substrate a secondary image to produce a resultant latent electrostatic image which isa function of said primary and secondary images and developing said resultant latent electrostatic image.
  • one of said primary and secondary images comprises the defocussed image of an original and the other of said images comprises the focussed image of said original.
  • a method for treating a picture image by electrophotography comprising the steps of;
  • a method for treating a picture image by electrophotography comprising the steps of;
  • a method for treating a picture image by electrophotography comprising the steps of;
  • a method for treating a picture image by an electrophotography comprising the steps of;
US356698A 1972-05-25 1973-05-02 Electrophotographic or xerographic method for treating a picture image Expired - Lifetime US3871878A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4297423A (en) * 1977-11-30 1981-10-27 Olympus Optical Company Limited Electrophotographic process for multiple images
US4329413A (en) * 1979-02-23 1982-05-11 Canon Kabushiki Kaisha Electrophotographic process capable of forming overlaid images and apparatus for carrying out the same
US4346982A (en) * 1979-04-20 1982-08-31 Fujitsu Limited Electrophotographic recording device
US4469767A (en) * 1978-12-26 1984-09-04 Canon Kabushiki Kaisha Electrophotographic process capable of image overlay and apparatus therefor
US4897330A (en) * 1986-12-09 1990-01-30 Konica Corporation Image forming method

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS53103738A (en) * 1977-02-23 1978-09-09 Hitachi Metals Ltd Method of taking electrophotography

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6056A (en) * 1849-01-23 Improvement in taking daguerreotype-pictures
US2155094A (en) * 1936-06-24 1939-04-18 Fred W Kiessling Graphic method and means
US3057719A (en) * 1958-07-09 1962-10-09 Xerox Corp Process for forming electrostatic images
US3248216A (en) * 1961-03-28 1966-04-26 Gen Aniline & Film Corp Process and apparatus for half-tone electrophotography
US3427658A (en) * 1966-05-06 1969-02-11 Harris Intertype Corp Electrophotographic apparatus and method
US3653891A (en) * 1969-12-31 1972-04-04 Xerox Corp Forms overlay technique using tesi

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2817765A (en) * 1956-01-03 1957-12-24 Haloid Co Xerographic method

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6056A (en) * 1849-01-23 Improvement in taking daguerreotype-pictures
US2155094A (en) * 1936-06-24 1939-04-18 Fred W Kiessling Graphic method and means
US3057719A (en) * 1958-07-09 1962-10-09 Xerox Corp Process for forming electrostatic images
US3248216A (en) * 1961-03-28 1966-04-26 Gen Aniline & Film Corp Process and apparatus for half-tone electrophotography
US3427658A (en) * 1966-05-06 1969-02-11 Harris Intertype Corp Electrophotographic apparatus and method
US3653891A (en) * 1969-12-31 1972-04-04 Xerox Corp Forms overlay technique using tesi

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4297423A (en) * 1977-11-30 1981-10-27 Olympus Optical Company Limited Electrophotographic process for multiple images
US4469767A (en) * 1978-12-26 1984-09-04 Canon Kabushiki Kaisha Electrophotographic process capable of image overlay and apparatus therefor
US4329413A (en) * 1979-02-23 1982-05-11 Canon Kabushiki Kaisha Electrophotographic process capable of forming overlaid images and apparatus for carrying out the same
US4346982A (en) * 1979-04-20 1982-08-31 Fujitsu Limited Electrophotographic recording device
US4897330A (en) * 1986-12-09 1990-01-30 Konica Corporation Image forming method

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JPS4910042A (fr) 1974-01-29
JPS5721708B2 (fr) 1982-05-08

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