US3764312A - Electrophotographic process - Google Patents

Electrophotographic process Download PDF

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Publication number
US3764312A
US3764312A US00213135A US3764312DA US3764312A US 3764312 A US3764312 A US 3764312A US 00213135 A US00213135 A US 00213135A US 3764312D A US3764312D A US 3764312DA US 3764312 A US3764312 A US 3764312A
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United States
Prior art keywords
toner
image
photoconductive
substrate
layer
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
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US00213135A
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English (en)
Inventor
S Honjo
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Fujifilm Holdings Corp
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Fuji Photo Film 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
    • G03G9/00—Developers
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G11/00—Selection of substances for use as fixing agents
    • 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
    • G03G15/22—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
    • G03G15/34—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the powder image is formed directly on the recording material, e.g. by using a liquid toner
    • G03G15/342—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the powder image is formed directly on the recording material, e.g. by using a liquid toner by forming a uniform powder layer and then removing the non-image areas
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G8/00—Layers covering the final reproduction, e.g. for protecting, for writing thereon
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/09—Colouring agents for toner particles
    • G03G9/0926—Colouring agents for toner particles characterised by physical or chemical properties
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
    • Y10S430/001—Electric or magnetic imagery, e.g., xerography, electrography, magnetography, etc. Process, composition, or product
    • Y10S430/101—Photoconductive powder

Definitions

  • This invention relates to electrophotography employing photoconductive toners, and more particularly to an improved method in electrophotography wherein image formation of more than two times can be realized on a single substrate.
  • FIG. 1 designates a substrate and 2 designates photoconductive toner electrically charged into a negative polarity.
  • the distribution of the electric charges within the toner layer is indicated schematically because the details thereof are not clear. A light image is then focused on the surface of the substrate 1.
  • Electric charge on the toner in a region strongly irradiated by the light rays is neutralized due to the photoconductive nature of the toner, and the electrostatic attraction between the substrate 1 and the toner 2 is thereby lost (see FIG. 2 where light is shown by the arrows).
  • the toner thus irradiated by light is then selectively removed by a suitable means (for instance, by an air stream jet) from the substrate, so that the image focused on the substrate develops (see FIG. 3 where toner 2 is shown selectively removed).
  • the image thus obtained in FIG. 3 may be transferred to another material or fixed on the substrate.
  • the toner includes a thermoplastic resin
  • fixation can be attained by the use of heat or a solvent.
  • a toner of a different color is again dispersed (sprinkled) on the substrate to be subjected to the recurrence of the above described processes, an image having two colors can be obtained.
  • a multi-color image is also obtained when the above described procedure is repeated as required.
  • photoconductive toners of superior behavior have been developed, and these toners are constructed as disclosed, for instance, in Japanese patent publication No. 12,385/ 1969, Belgium Pat. 710,572, etc. They may be from a transparent core typically consisting of an insulating resin, the outer surface of which is coated by a thin layer of a photoconductive substance. Such toners exhibit a lower residual potential after irradiation with light, and are far superior in comparison with toners of a uniform construction (having the same composition throughout the toner).
  • the newly developed toners are superior to conventional ones as described above, such toners are converted into an insulating layer having no photoconductivity when they are fixed by application of a solvent or heat and their useful structure is thereby destroyed.
  • the image formed by such toners is as shown in FIG. 3 and it is sprayed with a solvent 3 as indicated in FIG. 4, the toners are solved under the action of the solvent, and adhesively deposited on the surface of the substrate.
  • one object of the present invention is to provide an improved electrophotographic process whereby the above described drawbacks of the conventional electrophotography are substantially overcome.
  • the present invention in an electrophotography process wherein a substantially uniformly distributed powder layer consisting of minute photoconductive toner which consists of cores made of an insulating thermoplastic resin provided with a photoconductive layer is formed on a substrate having a conductive surface, said toners being thereafter electrostatically charged, a first lightimage being focused on said toner layer, toner in regions strongly irradiated by light rays being removed by 'a suitable procedure, thus forming a first toner image, said toner image being thereafter fixed, said steps being development of the first image so that regions having toners remaining are made electrically conductive to a desired extent. That is, the invention is characterized in that a treatment to convert the already developed toner to a conductive state is carried out before subsequent deposition (1) to overcome the highly insulative nature of the already developed toner layer.
  • FIGS. 1 through 3 are schematic sectional views for showing image forming processes employing photoconductive toners, which constitute fundamental processes in electrophotography.
  • FIGS. 4 and 5 are diagrams showing steps of electrophotography according to the present invention.
  • the photoconductive toner employed in the present invention has a highly advantageous structure as disclosed in Japanese patent publication 12,385/ 1969.
  • Such a toner is converted into a layer by means of a solvent or heat melting the core of the toner.
  • the core of the toner when it is made of glass or quartz, is developed (or deposited) on the substrate by spraying a resin solvent on the toner, and in this case an insulating layer is also formed on the substrate.
  • the previously formed image portion has a surface resistance value of ohms per square-cm. or less, and the exposed portion of the substrate should also be adjusted below the above-mentioned value. If the substrate has sufficient electrical conductivity after the image has been developed, only the image need be rendered conductive. This may be done by electrostatic spraying of conductive particles charged opposite in polarity to that of the developed image on which charge remains.
  • numeral 1 designates a substrate made of an electric conductor such as a metal, an insulator having a conductive layer on the surface, or a semiconductor.
  • the substrate or surface layer of the substrate should have a surface resistance less than 10 ohms per square-cm. This can be realized by a thin layer of an electric charge preventing agent or a conductive resin. Many of such materials have an adhesive nature, but in this invention, since the photoconductive toner should not be adhered to the surface layer of the substrate 1, materials having a low adhesive nature are selected for this purpose. This requirement is also found in the hereinafter described treatment for obtaining electrical conductivity.
  • Numeral 2 designates photoconductive toners having a construction as disclosed in the Japanese patent publication 12,385/1969.
  • toners are electrically charged before, simultaneously, or after they are dispersed on the surface of the substrate 1.
  • the relation between the amount of the toner dispersed and their performance characteristics was disclosed at the International Conference for Electronic Photography held at Rochester in September 1968.
  • the amount of toner dispersed is suitably 50-200 g./crn. and preferably 80 to 120 g./cm.
  • Toners having cores made of a transparent plastic resin are also described in Applied Optics, supplement 3, on Electrophotography (1969), pp. 124-128; H. Goto, K. Ohbuchi, S. Satamatsu,
  • the fixing step shown in FIG. 4 may be achieved by spraying a solvent over or by applying heat to the remaining toners. Whenever the core material of the toners cannot be melted by heat or dissolved in a solvent (although complete melting or dissolution is not required), the fixing step is attained by spraying a solution of a binding synthetic resin thereon such as silicone resin, polyvinyl acetate, polymer of vinyl chloride and vinyl acetate, polyacrylate, polymethacrylate, etc.
  • a binding synthetic resin thereon such as silicone resin, polyvinyl acetate, polymer of vinyl chloride and vinyl acetate, polyacrylate, polymethacrylate, etc.
  • the electrical conductivity treatment constituting the characteristic feature of the present invention may be carried out simultaneously with this fiXiIlg step, or as an independent step.
  • a solvent or solution containing an electrically conductive resin or charge preventing agent is employed in the fixing process for achieving fixation and rendering electrically conductive simultaneously.
  • the charge preventing agent or resin can be made into a separate solution and sprayed on the already fixed image.
  • a resin or agent for rendering conductive which is not easily dissolved in the fixing solution may be dispersed in the form of colloid, or reversely, the fixing resin solution may be dispersed in the form of colloid into the agent rendering conductivity.
  • quaternary ammonium salt polymers polyvinyl-benzyltrimethylammonium chloride, etc.
  • polyvinyl benzene sulfoxide polyvinyl benzene sulfoxide
  • colloidal alumina colloidal silica
  • quaternary ammonium salt type cation-activating agents or the like may be used for the same purpose.
  • the techniques disclosed in US. Pat. 3,295,967, US. Pat. 3,228,770, or in Japanese Pat. 14,035/1969 may also be utilized. Since the polymer or boundary surface activating agent tends to exhibit an adhesive nature, colloidal alumina or colloidal silica may be dispersed therein to reduce adherence.
  • any one particular conductivity rendering agent or charge preventing agent is not overly critical.
  • the material can be selected from a broad class, the above materials being only exemplary, so long as the conductivity and adhesivity requirements heretofore posed are met. It will be apparent that the ideal material has a non-adhesive nature for the toner later deposited and that as the adhesivity therefor increases, the excellent results obtainable in the present invention become lessened.
  • the above described conductivity rendering agents form a transparent layer over the image, and for this reason, they can be used for obtaining multi-color images. From 1 g. to 10 g. per onesq. meter of conductivity rendering agent is applied onto the image surface, and this amount is not significantly changed even when the agent contains other high resistance components. The important criterion is that the surface resistance of the image area be less than 10 ohms per sq. centimeter.
  • FIG. 5 indicates a state wherein the electric conductive layer 3 is formed over the toner image.
  • Photoconductive zinc oxide (Sazex #2000 manufactured by Sakai Chemical Ind.) parts by wt-.. Silicone resin varnish FSR-107 50% weight content (made by Fuji KobunshiInd. Co.) parts Cyclohexane do 20 parts of the'thus ground and dispersed mixture was added to 70 parts of polymethyl-methacrylate resin granules of an average grain size 70 microns (and having 2.5 mm.- of absorption factor for a radiant rays of 3800 A. which is within the specific sensible wavelength range of zinc oxide), and was stirred to obtain a coated photoconductive powder in the dried condition.
  • the photoconductive toner thus obtained was dispersed on a conductive black paper (carbon containing paper having a surface conductivity of about 10- mho square at 50% RH) at 80 g./m. of the surface area, and the black paper thus carrying toner particles was electrically charged in a dark room through corona discharge to have a negative polarity of about 300 volts. After the black paper was exposed to an image light of about 1000 lux sec. an air stream was blown onto the paper so that a white image was obtained on the background of black color.
  • a conductive black paper carbon containing paper having a surface conductivity of about 10- mho square at 50% RH
  • a fixing and conductivity rendering liquid made of parts of ECR-34 (Dow Chemical Co. aqueous solution containing 35% by weight polyvinyl-benzyl-trimethyl-ammonium chloride), 30 parts of Almina Sol 100 (Nissan Kagaku Co., an aqueous system colloid containing about 20% by weight colloidal almina), 20 parts of acetone, 50 parts of dimethylformamide, and 90 parts of methanol, was sprayed onto the element so that a 2 g./m. non-volatile layer was left on the image.
  • the above substances were ground and kneaded in a ball mill for about 17 hours.
  • 30 g. of the thus ground substances were added to a 100 g. of granular powder which was prepared by sieving an acrylic base MH-105 (made by Fujikura Kasei Co., having an absorption factor of 1.8 mm. for a radiant ray of 5500 A. wavelength within the specific sensitive wavelength range of cadmium yellow-orange) to have a minimum grain diameter of 35 microns and a maximum grain diameter of 104 microns.
  • the mixture was further stirred and dried by the application of hot air wind and lightly ground in a mortar into a powder-like structure.
  • the thus obtained powder was dispersed over the first image at a rate of 0.008 g./cm. electrically charged to an initial potential of about 260 volts, exposed to light forming a second image employing a xenon lamp, developed employing compressed air suitably blown onto the surface, and the second image of yellow-orange was obtained without any influence from the first image.
  • the second image was fixed employing dimethylformamide and an image having two colors was obtained.
  • the first image was simply fixed by dimethylformamide, dried, and then the second image formed as described above.
  • the first image was simply fixed by dimethylformamide, dried, and then the second image formed as described above.
  • first photoconductive toner prepared as follows was employed.
  • g I Parts Acrylic base MH-l05 by Fujikura Kasei Co.polymethacrylic-acid ethyl granular polymer, having a 60 to 70 K-value, grain size 60-100 meshes
  • Fuchsine 0.1 Methylene chloride 450 Parts Photoconductive zinc oxide (Sazex #2000)
  • Polystyrene 15 Cyclohexane 250 The thus obtained core bodies were red when they ware fixed by means of a solvent.
  • a mixed liquid at 1:1 weight ratio of dimethylformamide and methylene chloride was employed.
  • aqueous solution is 50 cp.) 10 Water emulsion of polybutylmethacryate (nonvolatile substance are 20%) 50 Water This treatment liquid was not repelled from the toner image of water repellent nature due to the existence of the anion activator contained in the emulsion.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Developing Agents For Electrophotography (AREA)
  • Photoreceptors In Electrophotography (AREA)
  • Electrophotography Using Other Than Carlson'S Method (AREA)
  • Fixing For Electrophotography (AREA)
US00213135A 1970-12-28 1971-12-28 Electrophotographic process Expired - Lifetime US3764312A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP45120543A JPS4926903B1 (fr) 1970-12-28 1970-12-28

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US3764312A true US3764312A (en) 1973-10-09

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US (1) US3764312A (fr)
JP (1) JPS4926903B1 (fr)
AU (1) AU469375B2 (fr)
CA (1) CA957541A (fr)
DE (1) DE2165031A1 (fr)
FR (1) FR2120854A5 (fr)
GB (1) GB1356610A (fr)
NL (1) NL7117937A (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3928655A (en) * 1973-03-05 1975-12-23 Fuji Photo Film Co Ltd Electrostatic powder coating method
US4095134A (en) * 1975-01-10 1978-06-13 U.S. Philips Corporation Electrophotographic preparation of color television display tube including rinsing phosphor pattern with solution of antistatic agent in apolar solvent
US4701389A (en) * 1985-07-11 1987-10-20 Mita Industrial Co., Ltd. Photoconductive toner
WO2012164015A1 (fr) * 2011-05-31 2012-12-06 University Of Warwick Construction d'additif

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5256203U (fr) * 1975-10-20 1977-04-22
JPS52164207U (fr) * 1976-06-07 1977-12-13
JPS5347505U (fr) * 1976-09-28 1978-04-22
JPS5349604U (fr) * 1976-09-30 1978-04-26
JPS5349605U (fr) * 1976-09-30 1978-04-26
JPS5385509U (fr) * 1976-12-15 1978-07-14
JPS545013U (fr) * 1977-06-15 1979-01-13
JPS5535862U (fr) * 1978-08-30 1980-03-07
GB2164935B (en) * 1984-09-28 1988-02-10 Electricity Council A process for the separation of mixtures of methyl esters of meta and para cresol

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3928655A (en) * 1973-03-05 1975-12-23 Fuji Photo Film Co Ltd Electrostatic powder coating method
US4095134A (en) * 1975-01-10 1978-06-13 U.S. Philips Corporation Electrophotographic preparation of color television display tube including rinsing phosphor pattern with solution of antistatic agent in apolar solvent
US4701389A (en) * 1985-07-11 1987-10-20 Mita Industrial Co., Ltd. Photoconductive toner
JPH0661006B2 (ja) 1985-07-11 1994-08-10 三田工業株式会社 光導電性トナーを用いた画像形成方法
WO2012164015A1 (fr) * 2011-05-31 2012-12-06 University Of Warwick Construction d'additif
CN103858060A (zh) * 2011-05-31 2014-06-11 华威大学 增材构造

Also Published As

Publication number Publication date
NL7117937A (fr) 1972-06-30
CA957541A (en) 1974-11-12
AU3744171A (en) 1973-07-05
FR2120854A5 (fr) 1972-08-18
GB1356610A (en) 1974-06-12
DE2165031A1 (de) 1972-07-20
AU469375B2 (en) 1976-02-12
JPS4926903B1 (fr) 1974-07-12

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