US3773507A - Electrophotographic reversal development process employing a pre-toner - Google Patents
Electrophotographic reversal development process employing a pre-toner Download PDFInfo
- Publication number
- US3773507A US3773507A US00159455A US3773507DA US3773507A US 3773507 A US3773507 A US 3773507A US 00159455 A US00159455 A US 00159455A US 3773507D A US3773507D A US 3773507DA US 3773507 A US3773507 A US 3773507A
- Authority
- US
- United States
- Prior art keywords
- toner
- charge
- coating
- latent image
- image
- 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
Links
- 238000000034 method Methods 0.000 title claims abstract description 15
- 239000011248 coating agent Substances 0.000 abstract description 32
- 238000000576 coating method Methods 0.000 abstract description 32
- 230000002950 deficient Effects 0.000 abstract description 8
- 239000002245 particle Substances 0.000 description 11
- 239000000203 mixture Substances 0.000 description 9
- 239000000843 powder Substances 0.000 description 8
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 7
- 239000007788 liquid Substances 0.000 description 7
- 239000011324 bead Substances 0.000 description 5
- 238000000151 deposition Methods 0.000 description 5
- 239000000049 pigment Substances 0.000 description 5
- 239000011347 resin Substances 0.000 description 5
- 229920005989 resin Polymers 0.000 description 5
- 239000001856 Ethyl cellulose Substances 0.000 description 4
- ZZSNKZQZMQGXPY-UHFFFAOYSA-N Ethyl cellulose Chemical compound CCOCC1OC(OC)C(OCC)C(OCC)C1OC1C(O)C(O)C(OC)C(CO)O1 ZZSNKZQZMQGXPY-UHFFFAOYSA-N 0.000 description 4
- 239000006229 carbon black Substances 0.000 description 4
- NNBZCPXTIHJBJL-UHFFFAOYSA-N decalin Chemical compound C1CCCC2CCCCC21 NNBZCPXTIHJBJL-UHFFFAOYSA-N 0.000 description 4
- 230000008021 deposition Effects 0.000 description 4
- 229920001249 ethyl cellulose Polymers 0.000 description 4
- 235000019325 ethyl cellulose Nutrition 0.000 description 4
- 239000003350 kerosene Substances 0.000 description 4
- 239000012260 resinous material Substances 0.000 description 4
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 3
- 239000006185 dispersion Substances 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 239000004615 ingredient Substances 0.000 description 3
- 235000021388 linseed oil Nutrition 0.000 description 3
- 239000000944 linseed oil Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 229910052711 selenium Inorganic materials 0.000 description 3
- 239000011669 selenium Substances 0.000 description 3
- CXWXQJXEFPUFDZ-UHFFFAOYSA-N tetralin Chemical compound C1=CC=C2CCCCC2=C1 CXWXQJXEFPUFDZ-UHFFFAOYSA-N 0.000 description 3
- 239000011787 zinc oxide Substances 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- 239000000020 Nitrocellulose Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- -1 alicyclic hydrocarbons Chemical class 0.000 description 2
- 150000004945 aromatic hydrocarbons Chemical class 0.000 description 2
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 2
- 239000002270 dispersing agent Substances 0.000 description 2
- 230000005294 ferromagnetic effect Effects 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 229920001220 nitrocellulos Polymers 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000002966 varnish Substances 0.000 description 2
- PXXNTAGJWPJAGM-UHFFFAOYSA-N vertaline Natural products C1C2C=3C=C(OC)C(OC)=CC=3OC(C=C3)=CC=C3CCC(=O)OC1CC1N2CCCC1 PXXNTAGJWPJAGM-UHFFFAOYSA-N 0.000 description 2
- 239000005995 Aluminium silicate Substances 0.000 description 1
- DKPFZGUDAPQIHT-UHFFFAOYSA-N Butyl acetate Natural products CCCCOC(C)=O DKPFZGUDAPQIHT-UHFFFAOYSA-N 0.000 description 1
- 229920002284 Cellulose triacetate Polymers 0.000 description 1
- 108010010803 Gelatin Proteins 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 1
- 235000010724 Wisteria floribunda Nutrition 0.000 description 1
- 239000005083 Zinc sulfide Substances 0.000 description 1
- NNLVGZFZQQXQNW-ADJNRHBOSA-N [(2r,3r,4s,5r,6s)-4,5-diacetyloxy-3-[(2s,3r,4s,5r,6r)-3,4,5-triacetyloxy-6-(acetyloxymethyl)oxan-2-yl]oxy-6-[(2r,3r,4s,5r,6s)-4,5,6-triacetyloxy-2-(acetyloxymethyl)oxan-3-yl]oxyoxan-2-yl]methyl acetate Chemical compound O([C@@H]1O[C@@H]([C@H]([C@H](OC(C)=O)[C@H]1OC(C)=O)O[C@H]1[C@@H]([C@@H](OC(C)=O)[C@H](OC(C)=O)[C@@H](COC(C)=O)O1)OC(C)=O)COC(=O)C)[C@@H]1[C@@H](COC(C)=O)O[C@@H](OC(C)=O)[C@H](OC(C)=O)[C@H]1OC(C)=O NNLVGZFZQQXQNW-ADJNRHBOSA-N 0.000 description 1
- FJWGYAHXMCUOOM-QHOUIDNNSA-N [(2s,3r,4s,5r,6r)-2-[(2r,3r,4s,5r,6s)-4,5-dinitrooxy-2-(nitrooxymethyl)-6-[(2r,3r,4s,5r,6s)-4,5,6-trinitrooxy-2-(nitrooxymethyl)oxan-3-yl]oxyoxan-3-yl]oxy-3,5-dinitrooxy-6-(nitrooxymethyl)oxan-4-yl] nitrate Chemical compound O([C@@H]1O[C@@H]([C@H]([C@H](O[N+]([O-])=O)[C@H]1O[N+]([O-])=O)O[C@H]1[C@@H]([C@@H](O[N+]([O-])=O)[C@H](O[N+]([O-])=O)[C@@H](CO[N+]([O-])=O)O1)O[N+]([O-])=O)CO[N+](=O)[O-])[C@@H]1[C@@H](CO[N+]([O-])=O)O[C@@H](O[N+]([O-])=O)[C@H](O[N+]([O-])=O)[C@H]1O[N+]([O-])=O FJWGYAHXMCUOOM-QHOUIDNNSA-N 0.000 description 1
- 150000001338 aliphatic hydrocarbons Chemical class 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 1
- 235000012211 aluminium silicate Nutrition 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 239000002801 charged material Substances 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 229920005994 diacetyl cellulose Polymers 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 229920000159 gelatin Polymers 0.000 description 1
- 239000008273 gelatin Substances 0.000 description 1
- 235000019322 gelatine Nutrition 0.000 description 1
- 235000011852 gelatine desserts Nutrition 0.000 description 1
- FUZZWVXGSFPDMH-UHFFFAOYSA-N hexanoic acid Chemical compound CCCCCC(O)=O FUZZWVXGSFPDMH-UHFFFAOYSA-N 0.000 description 1
- 239000008240 homogeneous mixture Substances 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 1
- 239000011133 lead Substances 0.000 description 1
- 230000005291 magnetic effect Effects 0.000 description 1
- 229920005615 natural polymer Polymers 0.000 description 1
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 239000004926 polymethyl methacrylate Substances 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 229920002689 polyvinyl acetate Polymers 0.000 description 1
- 239000011118 polyvinyl acetate Substances 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 235000019422 polyvinyl alcohol Nutrition 0.000 description 1
- 229920000915 polyvinyl chloride Polymers 0.000 description 1
- 239000004800 polyvinyl chloride Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 229920001059 synthetic polymer Polymers 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- 229910052984 zinc sulfide Inorganic materials 0.000 description 1
- DRDVZXDWVBGGMH-UHFFFAOYSA-N zinc;sulfide Chemical compound [S-2].[Zn+2] DRDVZXDWVBGGMH-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
-
- 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
Definitions
- Kanagawa, Japan 57 ABSTRACT [22] Filed: July 2, 1971 pp No 159 455 A reversal development process which comprises, after uniformly charging a photoconductive insulating coating with a charge of one polarity, applying a finely [30] Foreign Application Priority Data divided pre-toner having a white or off-white appear- July 13, 1970 Japan 45/60875 anee and a Charge of the Same P y as that of the uniform charge whereby the pre-toner deposits at the 52 US. (:1. 96/1 R, 96/1 so, 96/1 LY, charge-deficient areas in the eeeting, then subjecting 1 17/175 252/62 1 the thus treated coating to image exposure to form an 51 Int. Cl.
- An optically positive toner image results by uniformly charging an electrofax sheet material in a subdued light, then exposing said charged material to an optically negative image of light and shadow to form an electrostatic latent image, and then by developing the latent image by the application of toner having the same polarity of charge as that of the latent image.
- the photoconductive coating is made of a homogeneous mixture comprising a finely divided powder photoconductor and a resinous binder
- the coating has microscopic irregularities which will not be present in an organic photoconductive layer or amorphous selenium layer having a uniform structure in molecular order. Such irregularities cause local electrical breakdown when the coating is subjected to corona charging, and at such areas where the impinged corona ions undergo breakdown discharge the charged density will be nearly zero or greatly lower than the surroundings.
- pin hole areas in the coating will be developed as black spots in a white background in reversal development in which toner predominantly deposits at lower charge density areas.
- the invention provides a reversal development method which overcomes the above-cited shortcomings, and is characterized by that a photoconductive insulating coating is imparted an electrostatic charge of one polarity, supplied with finely divided powder of the same color as that of the photoconductive insulating coating and of the same polarity whereby the powder particles deposit at the charge deficient pin hole areas in the charged coating, then subjected to image exposure to form an electrostatic latent image, and finally developed with colored finely divided marking powder also having the same polarity of charge as that of the latent image.
- the white or off-white powder will be referred to as pre-toner while the marking powder as toner.
- the essential feature of the present invention resides in that pre-toner is allowed to deposit or mask the charge-deficient spots formed during charging of the coating in order that such spots will no longer attract toner in the subsequent image development. It should be emphasized that in the present inventions the pretoner is applied onto the coating prior to the image exposure.
- pre-toner after image exposure is far .less effective for the present purpose.
- the reason is as follows; prior to image exposure deposition of pretoner will proceed only at the charge deficient spots while, on the other hand, application of pre-toner after image exposure will result in deposition of the pretoner not only at the charge-deficient spots but also at areas where charge density changes abruptly. This will make it impossible to produce a toner image of desirable quality since the toner will deposit with a reduced deposition density at those areas.
- Suitable particles for pre-toner in the present invention include colorless or pale colored, finely divided natural or synthetic polymers, white or off-white pigments, mixtures of polymer and pigment particles, or similar pigments encapsulated with polymeric materials, etc.
- Suitable polymers are ethyl cellulose, nitrocellulose, triacetylcellulose, diacetylcellulose, polyvinylacetate, polyvinylalcohol, gelatin polymethylmethacrylate, polyvinylchloride, polycarbonate, etc.
- examples of pigments are barium sulfate, calcium carbonate, kaolin, aluminum hydroxide, zinc oxide, titanium dioxide, zinc sulfide, lead white, etc.
- compositions of toner those well known for those skilled in the art by already disclosed literatures or patent may be applicable for the present invention, including those for dry development comprising carbon black and resinous material or those for liquid development comprising pigment particles associated with resinous materials absorbed on the surface of the particles.
- the present invention is effective when combined with or applied on a photoconductive coating comprising a finely divided photoconductor and resinous binder, it is also applicable to a homogeneous layer comprising organic photoconductor or amorphous selenium.
- a photoconductive insulating coating was provided by vacuum depositing amorphous selenium on an aluminum plate. This coating exhibited pin-hole like charge-deficient spots in repeated use.
- the plate was charged by corona to +1000 volts, and then immersed in a dispersion comprising kerosene as dispersant in which a small quantity of linseed oil was dissolved as a dispersing-agent and finely divided ethylcellulose of l to 10 micron diameter which had a positive polarity of charge. After about a 10 second immersion, the plate was pulled out and then subjected to an image exposure utilizing a negative transparency.
- the exposed plate was then developed with a liquid developer which had been prepared by dispering a blended mixture of carbon black and ethyl cellulose in kerosene in which was dissolved a small quantity of linseed oil.
- the particle diameter of the pigmented-resin toner fell in the range between 1 and.l0 microns.
- the plate was drawn from the developer and superimposed ith a sheet of ordinary paper while the surface of the plate was still wet.
- the assemble was subjected to negative corona from the back surface of the paper. Then the sheet was separated onwhich there was obtained a positive print free of pin hole spots.
- a white photoconductive insulating coating was prepared on paper support by coating a blended mixture of photoconductive zinc oxide and insulating binder. The coating was negatively charged to about 500 volts by corona. Prior to image exposure a mixture comprising 0.5 to 1 mm diameter glass beads overcoated with a thin film of ethyl cellulose and pre-toner of 5 to 20 micron diameter vinylchloride and vinyl acetate copolymer which were adhered electrostatically to the surface of the beads was cascaded onto the surface of the coating.
- the coating was subjected to image exposure utilizing a negative transparency.
- Developement was carried out by cascading developer mixture comprising the glass beads carrier described above and a pigmented resin comprising polystyrene and carbon black having a diameter of about 10 to 30 microns.
- the resulting image was free of pin-hole spots in the background area.
- Example ll Another sheet of the electrophotographic paper in Example ll was charged 400 volts in subdued light, and then immersed in the following pre-toner dispersion of for 10 seconds:
- Zinc oxide powder (particle diameter 0.05 to 0.5 microns) l parts Linseed oil 10 parts Resin varnish parts Kerosene 1000 parts Cyclohexanc 200 parts Carbon black (particle diameter 0.0]
- pre-toner application can not only expel pin-hole spots but also serve to prevent undesirable adhesion of toner due to forces other than electrostatic.
- the present invention may be practiced by liquid or dry development.
- the present invention is more advantageously carried out by the former method of development which can provide electrophotographic prints of quite high quality having tonal rendition wherein black pin-hole spots in the highlight or background areas will fatally affect the image quality.
- pre-toner on the photoconductive coating care must be taken not to greatly decrease the surface charge density, or else one will fail to obtain a toner image with sufficient contrast and density by the subsequent development operation.
- the electrical resistance of the dispersion liquid should be high enough and the liquid should have a poor affinity for the resinous hinder or resinous ingredient in the photoconductive coating.
- Preferable solvents may be isoparaffinic, which have poor dissolving power for many resinous materials, but more active solvents such as straight chain hydrocarbons, alicyclic hydrocarbons, decalin, or tetralin, and further, aromatic hydrocarbons, or mixtures of aliphatic and aromatic hydrocarbons may also be used if the resinous ingredient is cured.
- the carrier particles should not be electrically conductive.
- powder cloud development involves no problem of charge leakage due to pre-toner application.
- Carrier particles for brush or cascade development which are suitable for use in the application of pretoner include glass beads, natural silica sands, diamond beads, ferromagnetic iron powder, and ferromagnetic alloy powder, all of which are surface coated with insulating resinous materials.
- pre-toner should perform similarly as the underlying photoconductive coating.
- a suitable example of a pre-toner is dye-sensitized zinc oxide encapsulated by insulating resin.
- an electrically insulating pre-toner is desirable for the following reason: The charge on the pretoner will be neutralized after deposition, draining to the ground through the insulating coating, in which case colored toner will again deposit on the pre-toner in the subsequent development and no improvement of image quality results. Fortunately, however, this is not so serious a problem since the pin-hole areas where electrical breakdown has occurred become insulating again immediately after charging.
- pretoner and toner one may employ dry and/or liquid methods.
- a reversal development process which comprises; after uniformly charging a photoconductive insulating coating with a charge of one polarity, applying a finely divided, photoconductive, pre-toner having the same color as that of said photoconductive insulating coating and a charge of the same polarity as that of said uniform charge whereby the pre-toner deposits at the charge-deficient areas in the coating, then subjecting the thus treated coating to image exposure to form an electrostatic latent image; and finally developing said latent image by applying a finely divided toner differently colored from said pre-toner, said toner having a charge of the same polarity as that of said latent image.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Photoreceptors In Electrophotography (AREA)
- Developing Agents For Electrophotography (AREA)
- Magnetic Brush Developing In Electrophotography (AREA)
- Developing For Electrophotography (AREA)
- Dry Development In Electrophotography (AREA)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP45060875A JPS495465B1 (enrdf_load_stackoverflow) | 1970-07-13 | 1970-07-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3773507A true US3773507A (en) | 1973-11-20 |
Family
ID=13154975
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US00159455A Expired - Lifetime US3773507A (en) | 1970-07-13 | 1971-07-02 | Electrophotographic reversal development process employing a pre-toner |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US3773507A (enrdf_load_stackoverflow) |
| JP (1) | JPS495465B1 (enrdf_load_stackoverflow) |
| BE (1) | BE769893A (enrdf_load_stackoverflow) |
| CA (1) | CA947812A (enrdf_load_stackoverflow) |
| FR (1) | FR2100351A5 (enrdf_load_stackoverflow) |
| GB (1) | GB1340947A (enrdf_load_stackoverflow) |
| NL (1) | NL7109372A (enrdf_load_stackoverflow) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3901698A (en) * | 1971-12-10 | 1975-08-26 | Rank Xerox Ltd | Method of reversal development using two electrostatic developers |
| US3928655A (en) * | 1973-03-05 | 1975-12-23 | Fuji Photo Film Co Ltd | Electrostatic powder coating method |
| US4031021A (en) * | 1974-03-25 | 1977-06-21 | Deming Philip H | Magnetic toner compositions |
| US4828950A (en) * | 1987-12-28 | 1989-05-09 | Eastman Kodak Company | Method for making multi-color reproductions on plain bond paper |
| US4897331A (en) * | 1987-06-03 | 1990-01-30 | Minolta Camera Kabushiki Kaisha | Reversal image forming method |
| US4975348A (en) * | 1987-06-03 | 1990-12-04 | Minolta Camera Kabushiki Kaisha | Image highlighting method |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5391578U (enrdf_load_stackoverflow) * | 1976-12-24 | 1978-07-26 |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3512965A (en) * | 1963-07-12 | 1970-05-19 | Australia Res Lab | Electroprinting method |
-
1970
- 1970-07-13 JP JP45060875A patent/JPS495465B1/ja active Pending
-
1971
- 1971-07-02 US US00159455A patent/US3773507A/en not_active Expired - Lifetime
- 1971-07-06 CA CA117,431A patent/CA947812A/en not_active Expired
- 1971-07-07 NL NL7109372A patent/NL7109372A/xx unknown
- 1971-07-07 FR FR7124853A patent/FR2100351A5/fr not_active Expired
- 1971-07-12 BE BE769893A patent/BE769893A/xx unknown
- 1971-07-13 GB GB3290171A patent/GB1340947A/en not_active Expired
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3512965A (en) * | 1963-07-12 | 1970-05-19 | Australia Res Lab | Electroprinting method |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3901698A (en) * | 1971-12-10 | 1975-08-26 | Rank Xerox Ltd | Method of reversal development using two electrostatic developers |
| US3928655A (en) * | 1973-03-05 | 1975-12-23 | Fuji Photo Film Co Ltd | Electrostatic powder coating method |
| US4031021A (en) * | 1974-03-25 | 1977-06-21 | Deming Philip H | Magnetic toner compositions |
| US4897331A (en) * | 1987-06-03 | 1990-01-30 | Minolta Camera Kabushiki Kaisha | Reversal image forming method |
| US4975348A (en) * | 1987-06-03 | 1990-12-04 | Minolta Camera Kabushiki Kaisha | Image highlighting method |
| US4828950A (en) * | 1987-12-28 | 1989-05-09 | Eastman Kodak Company | Method for making multi-color reproductions on plain bond paper |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS495465B1 (enrdf_load_stackoverflow) | 1974-02-07 |
| FR2100351A5 (enrdf_load_stackoverflow) | 1972-03-17 |
| GB1340947A (en) | 1973-12-19 |
| DE2134981B2 (de) | 1976-04-15 |
| DE2134981A1 (de) | 1972-01-20 |
| BE769893A (fr) | 1971-11-16 |
| NL7109372A (enrdf_load_stackoverflow) | 1972-01-17 |
| CA947812A (en) | 1974-05-21 |
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