US3712728A - Reversal development - Google Patents
Reversal development Download PDFInfo
- Publication number
- US3712728A US3712728A US00104331A US3712728DA US3712728A US 3712728 A US3712728 A US 3712728A US 00104331 A US00104331 A US 00104331A US 3712728D A US3712728D A US 3712728DA US 3712728 A US3712728 A US 3712728A
- Authority
- US
- United States
- Prior art keywords
- imaging surface
- developer
- development
- areas
- liquid developer
- 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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Classifications
-
- 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
- G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
- G03G15/10—Apparatus for electrographic processes using a charge pattern for developing using a liquid developer
- G03G15/101—Apparatus for electrographic processes using a charge pattern for developing using a liquid developer for wetting the recording material
- G03G15/102—Apparatus for electrographic processes using a charge pattern for developing using a liquid developer for wetting the recording material for differentially wetting the recording material
-
- 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
-
- 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
- G03G9/12—Developers with toner particles in liquid developer mixtures
Definitions
- the formation and development of images on the surface of photoconductive materials by electrostatic means is well known.
- the basic electrostatographic process as taught by C. F. Carlson in U.S. Pat. No. 2,297,691 involves placing a uniform electrostatic charge on a photoconductive insulating layer, exposing the layer to a light and shadow image to dissipate the charge on the areas of the layer exposed to the light and developing the resulting electrostatic latent image by depositing on the image a finely divided electroscopic material referred to in the art as toner.”
- the toner will normally be attracted to those areas of the layer which retain a charge, thereby forming a toner image corresponding to the electrostatic latent image.
- This powder image may then be transferred to a support surface such as paper.
- the transferred image may subsequently be permanently affixed to a support surface as by heat.
- latent image formation by uniformly charging the photoconductive layer and then exposing the layer to a light and shadow image
- the powder image may be fixed to the .photoconductive layer if elimination of the powder image transfer step is desired.
- Other suitable fixing means such as solvent or overcoating treatment may be substituted for the foregoing heat fixing step.
- electrostatic latent image may also be achieved with liquid rather than dry developer materials.
- electrophoretic development an insulating liquid vehicle having finely divided solid material dispersed therein contacts the imaging surface in both charged and uncharged areas. Under the influence of the electric field associated with the charged image pattern, the suspended particles migrate toward the charged portions of the imaging surface separating out of the insulating liquid. This electrophoretic migration of charged particles results in the deposition of the charged particles on the imaging surface or image configuration.
- a further technique for developing electrostatic latent images is the liquid development process disclosed by R. W. Gundlach in U.S. Pat. No. 3,084,043 hereinafter referred to as polar liquid development.
- an electrostatic latent image is developed or made visible by presenting to the imaging surface a conductive liquid developer on the surface of a developer dispensing member having a plurality of raised portions or lands defining a substantially regular patterned surface and a plurality of portions depressed below the raised portions or valleys.
- depressed portions of the developer dispensing member contain a layer of conductive liquid developer which is maintained out of contact with the electrostatographic imaging surface. Development is achieved by moving the developer dispensing member loaded with liquid developer in the depressed portions adjacent the imaging surface. While not necessary the imaging surface and the developer dispensing member may be in light or gentle contact. The liquid developer is believed to be selectively attracted from the depressed portions of the applicator surface in areas where an electrostatic field exists. With the use of a conventional electrophotographic plate which has been charged and exposed to a light and shadow pattern, the charged or image areas are developed. The developed liquid may be pigmented or dyed.
- 3,084,043 differs from electrophoretic development systems where substantial contact between the liquid developer and both the charged and uncharged areas of an electrostatic latent imaging surface occurs. Unlike electrophoretic development systems, substantial contact between the polar liquid and the areas of the electrostatic latent image bearing surface not to be developed is prevented in the polar liquid development technique. Reduced contact between a liquid developer and the nonimage areas of the surface to be developed is desirable because the formation of background deposits is thereby inhibited.
- Another characteristic which distinguishes the polar liquid development technique from electrophoretic development is the fact that the liquid phase of a polar developer actually takes part and physically moves during development in response to the electrostatic field. The liquid phase in electrophoretic developers functions only as a carrier medium for developer particles.
- a certain minimum field termed threshold field is required between the developer applicator and the imaging surface to draw the liquid developer from the recessed portions of the applicator onto the imaging surface.
- This threshold field may be described in terms of potential difference which typically is from about 50 to about volts. Liquid developer moves from the developer applicator to the imaging surface in areas where the local difference in potential exceeds the minimum threshold potential.
- the polar liquid development process is therefore independent of field polarity or direction as well as of the absolute potentials of the imaging surface and the developer applicator.
- these polar liquid development systems may be improved upon in certain areas. Particular areas of improvement include those wherein reversal imaging is to be accomplished, Reversal imaging may be accomplished by biasing the developer applicator to substantially the same potential as the maximum potential on the imaging surface.
- substantially the same potential it is intended to define that potential range which may be permitted where the difference in maximum potential on the imaging surface and that placed on the developer applicator is below the threshold potential.
- the imaging surface is a photoconductive insulating layer which has been uniformly charged and exposed in conventional manner
- the charged areas correspond to the dark areas of the original light and shadow pattern, while the discharged areas are those which have been illuminated. Biasing the developer dispensing member, as described above, causes development selectively in the illuminated areas of the imaging surface.
- the electrostatographic imaging surface has liquid developer present in the uncharged areas and retains the charge in image configuration in the charged area.
- the polar liquid developer present in the uncharged areas of the imaging surface spreads from the reversal image areas into the adjacent charged areas of the imaging surface. This is believed to be due to the fact that since the liquid developer is polar and therefore conductive, it is attracted to regions of high field gradients.
- the edge gradient is particularly strong in the immediately adjacent charged area surrounding the liquid developer and therefore the conductive developer tends to creep into the charged areas of the edge. This lateral spreading of the liquid developer on the imaging surface results in a reduction in resolution and very marked reduction in the sharpness of the reversal image produced during development.
- the electrostatographic imaging member may be discharged in any suitable manner.
- the charge pattern may be discharged by blanket illumination of the photoconductor following development.
- the electrostatographic imaging surface may be electrostatically discharged by means, for example, of a corona discharge device.
- any other suitable source of radiation may be employed to discharge the charged image ares of the imaging surface.
- the discharge is to a level such that the electrostatic field between the charged areas on the imaging surface and the polar liquid developer is insufficient to cause the polar liquid developer to spread into the charged areas.
- spreading of the polar liquid developer is observed to take place with time. Accordingly, it is desired to discharge the charged undeveloped portions of the imaging surface as soon after development as possible. Preferably, this is accomplished within a period of time such that there is substantially no lateral spreading or feathering of the polar liquid developer into the charged areas of the imaging surface.
- the rate of lateral spreading is partially dependent upon the magnitude of potential on the imaging surface in the undeveloped areas and upon the viscosity of the liquid developer.
- the rate of spreading also increases.
- the rate of lateral spreading is generally inversely proportional to the viscosity of the liquid developer.
- the period of time between development and discharge should be such as to minimize the adverse lateral spreading effects which may be attributable to these parameters.
- the rate of spreading may also, to a minor extent, be dependent upon the structure of the imaging surface such as its thickness and dielectric constant.
- polar liquid developers having viscosities of from about 300 to about 5000 centipoises at 25 C. as measured by a Model LVT Brockfield viscometer and for imaging surfaces bearing maximum potentials of about l000 volts if discharge of the charge nondeveloped areas of the imaging surface is accomplished within about 0.5 seconds following development, substantially no lateral spreading of the liquid developer will take place. In insuring a minimum lateral spreading of the developer, it is preferred to discharge the charged portions of the imaging surface within about 0.2 following development.
- FIGS. 1 through 4 are schematic illustrations of the reversal development system according to this inventron.
- FIG. 5 is a schematic view of a preferred imaging system.
- an electrostatographic member here illustrated as the photoconductive insulating layer which comprises a photoconductive layer 11 on a conductive substrate 12 is charged and exposed to a light and shadow patternin conventional manner to produce the electrostatic charge pattern depicted.
- Development is obtained by positioning a developing dispensing member 13 having a substantially uniform surface pattern of raised and depressed portions with the polar liquid developer present in the depressed portions 14 adjacent to the photoconductor.
- the developer dispensing member and polar liquid developer present thereon are biased to a polarity, the same as the polarity of charge placed on the photoconductor by means of potential source 15 and in an amount substantially the same as the potential applied to the image areas of the photoconductor.
- FlG. 2 substantially depicts the imaging surface immediately following development in which the polar liquid developer has been deposited in the nonimage uncharged areas of the photoconductive insulating layer.
- FIG. 3 schematically illustrates the imaging surface shortly following development and after discharge of the polar liquid developer as will be discussed hereinafter. Due to the potential difference existing between the liquid developer and the surrounding charged undeveloped areas of the photoconductor, charges of opposite polarity are induced at the surface of the liquid developer adjacent the surrounding undeveloped areas which establish a field producing a force on the liquid developer outward and normal to the surface of the liquid which is sufficient to cause the liquid developer to laterally flow at the edge into the undeveloped areas.
- FlG. 4 schematically illustrates the imaging surface after development and after it has been uniformly discharged to a level which reduces the field on the liquid developer to values which are insufficient to produce any significant lateral spreading of the liquid developer.
- this discharge of the imaging surface is to a level less than about volts.
- FIG. 5 a reversal development system is depicted wherein a photoconductor here illustrated as endless belt 17 is positioned around driving and tensioning rollers 18 and is passed through the sequential imaging operations.
- the photoconductor is charged by means of corona discharge device 19 and exposed to a light and shadow pattern by exposure means 20.
- Development takes place by supplying liquid developer 24 from bath 23 by means of feed roll 22 to applicator roll 21.
- the applicator roll has a trihelicoid grooved pattern cut into the surface and the raised portions or lands are wiped substantially clean of polar liquid developer by means of doctor blade 25.
- the applicator roll and liquid developer thereon are biased to a potential substantially the same as that on the photoconductor by means of potential source 30.
- the electrostatographic imaging member is uniformly illuminated by means of lamp 26. If desired the developed image on the electrostatographic imaging member may be transferred to receiving member 27, fed into pressure contact with driving and tensioning roller 18 by means of backup roll 28.
- the supply of transfer image receiving member may be either sheet like or in the form of a continuous roll fed from feed roll 29.
- the electrostatic charge pattern may be formed in any suitable manner on any suitable electrostatographic imaging surface.
- the electrostatic charge pattern may, for example, be formed by charging the imaging surface in image configuration or alternatively, by uniformly charging a photoconductive insulating layer and then exposing the layer to a light and shadow pattern. Basically, any surface upon which an electrostatic charge pattern may be formed and maintained for a short period of time during which it is developed may be employed.
- Typical electrostatographic imagingsurfaces include dielectrics such as plastic coated papers, masters comprising insulating layers in image configuration on conductive substrates and photoconductors.
- Typical photoconductors that may be employed include selenium and selenium alloys, cadmium sulfide, cadmium sulfoselenide, phthalocyanine binder coatings and polyvinyl carbazole sensitized with 2,4,7, trinitrofluoronone.
- the electrostatographic imaging surface may be employed in any suitable structure including, plates, belts or drums and may be employed in the form of a binder layer coated on the substrate. The imaging surfaces may be overcoated with suitable dielectric materials in conventional manner.
- Reversal development on the electrostatographic imaging surface may be obtained in any suitable manner. Any suitable polar liquid developer may be employed. Typically, the developers for which the reversal development technique of this invention are effective have resistivities of from about 10 ohm-cm to about 10 ohm-cm.
- the liquid developers employed in the practice of this invention are polar in that they have the ability of having charge of either positive or negative polarity induced in them with equal ability.
- Typical vehicles within this group providing these properties include glycerol, polypropylene glycol, 2,5-hexanediol, mineral oil, the vegetable oils including castor oil, peanut oil, coconut oil, sunflower seed oil, corn oil, rapeseed oil, and sesame oil.
- the developers may contain one or more secondary vehicles, dispersants, pigments or dyes, viscosity controlling agents or additives which contribute to fixing the pigment on copy paper.
- the liquid developers employed may be of any suita ble viscosity. Since during development it is generally desirable to have the liquid flow from the developer dispensing member to the imaging surface developers having viscosities of from about 300 to about 5000 centipoises measured at 25 C. are preferred. Since the difficulties in the reversal development system discussed above depend to some extent on the ability of the liquid developer to flow it may be desirable to select a developer having a viscosity consistent with other development parameters and most resistant to flow. This balance between optimum viscosity for reduced spreading and viscosity necessary for any particular development speed or image density may be readily determined by one skilled in the art.
- Development may be obtained by placing the applicator surface sufficiently close to the electrostatographic imaging surface such that the polar liquid developer is pulled from the recessed portions of the applicator surface to the imaging surface in the reversal image configuration.
- Reversal development is obtained by applying to the developer applicator a potential of the same polarity and of substantially the same magnitude as the potential applied to the charged areas of the imaging surface.
- This provides an electrostatic field between the uncharged areas of the imaging surface and the developer on the applicator surface.
- a charge is induced in the developer in response to the electrostatic field and the developer creeps up the recessed portions of the applicator surface adjacent areas of the imaging surface which are uncharged.
- the developer applicator together with the polar liquid developer present on the applicator surface function as a development electrode in known manner.
- an electrostatographic imaging surface is positively charged and the developer applicator has applied to it a positive potential of about the same magnitude as the potential on the imaging surface, no field will exist between the developer applicator and the charged areas of the imaging surface and therefore, no liquid developer will be pulled from the recessed portions of the developer applicator to the imaging surface in the charged areas.
- a field does exist between the applicator functioning as a development electrode and the imaging surface and the polar liquid developer will be pulled from the recessed portions of the applicator surface to the imaging surface to develop the uncharged background areas providing a reversal print.
- any suitable applicator surface may be employed to dispense the polar liquid developer.
- the applicator surfaces have substantially uniform patterns of raised portions and depressed portions with the depressed portions being sufficiently large to hold sufficient liquid developer to provide adequate image density during development.
- Typical applicator surfaces include among others porous ceramics, metallic sponge, patterned webs or belts, capillary combs and cylindrical rolls having surface patterns such as single screwcuts or trihelicoid, pyramidial or quadragravure indentations.
- the applicator surface have a pattern comprising between about and about 300 demarcations of raised or depressed areas per inch.
- a pattern of recessed grooves such as in the trihelicoid pattern since this pattern facilitates better doctoring of the applicator surface.
- the applicator surface may be loaded with developer in any suitable manner.
- Typical developer loading techniques include applying developer from a roll or sponge roll or immersing the applicator in a bath. Prior to contacting the imaging surface, the applicator surface should be wiped or doctored" clean to remove substantially all liquid developer from the raised portions of the applicator surface. Any suitable means may be provided as the doctoring device.
- Typical doctoring devices include scraper blades and squeegee rolls. The doctoring in addition re removing liquid developer from the raised portions of the applicator surface preferably provides a slight wiping action of the liquid developer in the recessed portions of the applicator surface to thereby maintain the level of the liquid developer in the recessed portions slightly below the level of the raised portions. Such a loading of developer on the applicator surface minimizes deposits in the nlow areas.
- the developed image may be transferred to a receiving sheet such as ordinary paper in any suitable manner. It may, for example, be accomplished by contacting the imaging surface with the receiving member while under pressure. While pressure transfer is generally preferred because of its simplicity and effectiveness electrostatic transfer by means of a corona transfer device located at or immediately before the line of contact between the receiving surface and the imaging surface during the transfer operation may also be employed.
- the electrostatic field created by the corona transfer device is effective to tack the developer receiving material electrostatically to the imaging surface whereby it moves synchronously with the imaging surface while in contact.
- the electrostatic field is effective to attract the developer in image configuration from the imaging surface and cause it to adhere electrostatically to the surface of the receiving member.
- this discharge of the charged developer may take place by contact with the grounded backing behind the dielectric imaging layer, for example, through some pinhole defect in the imaging surface-or perhaps by some type of charge injection mechanism through the bulk of the imaging layer.
- a lateral field- is quickly built up between the charged portions of the imaging surface and the polar liquid developer which field exerts a force sufficient to cause the liquid developer to flow as depicted in FIG. 3. It has been observed that this flow is not necessarily uniform and in fact is quite erratic at times, suggesting that perhaps the liquid developer flows toward areas of highest potential gradients.
- the potential on the imaging surface varies spatially on a microscopic scale and that the developer follows a path of highest potential gradients, i.e. where the potential difference between the developer and adjacent local surface is great.
- the edge gradient is strong not only in the discharged area, but in the immediately adjacent charged area and that the conductive developer tends to creep into the remaining charged side of the edge. Once in that position, it discharges that area. After this occurs, the position of the edge gradients will have moved forward. As it moves forward, it carries with it the potential gradient pattern.
- the new position of the potential gradient pattern will again cause the liquid developer to be attracted into the new edge of the charged area where it will again cause discharge.
- the process of spreading is a continuing one in which the polar liquid developer follows the gradient and pushes it outward as it does so.
- the difficulties encountered with the spreading of the developed polar liquid developer image are substantially completely avoided. If following development and before any substantial spreading of the liquid developer on the imaging surface occurs, the charged portions of the imaging surface are discharged to a level below which there will be insufficient potential gradient to cause the conductive liquid developer to spread images of excellent sharpness, resolution and contrast density will be achieved.
- An electrophotographic imaging member comprising a binder layer containing photoconductive phthalocyanine particles overcoated on a conductive substrate is charged positively to a potential between 500 and 600 volts and subsequently, imagewise exposed. Reversal development is obtained by moving the photoconductor layer past and in light contact with a cylindrical roll having a surface trihelicoid pattern of about lines per inch cut at an angle of 45 to the axis of the roller.
- the grooved portion of the roller is supplied with polar liquid developer in a manner similar to that depicted in the development section of FIG. 4.
- the liquid developer is of the following composition by weight:
- Ganex V-2I6 15 parts
- Microlith CT Black 18 parts VM550 methyl violet tannate flushed pigment 3 parts
- Paraflint RG wax 0.5 parts
- Ganex V-216 is an alkylated polyvinyl pyrrolidone available from GAF corporation.
- Microlith CT Black is a resinated, predispersed carbon black pigment composed of about 40% carbon black and 60% ester gum resin and available from CIBA.
- VMS50 methyl violet tannate is a pigment available from Magruder Color Company and Paraflint R6 is a hydrocarbon wax available from Moore and Munger Corporation.
- the liquid developer has a resistivity of about 10 ohm-cm.
- Reversal development is obtained by applying a bias of +500 volts to the developer applicator and within about 0.2 seconds following development the imaging member is blanket illuminated to discharge the charged undeveloped areas.
- the developed image which is of acceptable commercial quality, is sharp and clear and characters of ordinary typewriter dimension are accurately reproduced and easily read.
- Example I The procedure of Example I is repeated except that within about 0.5 seconds'following development the electrophotographic imaging member is uniformly illuminated to discharge the charged undeveloped areas. Within three seconds of development, the liquid developer istransferred to ordinary bond paper. The image on bond paper is as clear and sharp and of quality comparable to Example 1.
- Example IV The procedure of Example lll is repeated except that the illumination step is completely omitted.
- the image on bond paper shows considerable spreading of the liquid developer giving a very feathery appearance and marked loss of sharpness.
- a reversal imaging system comprising an electrostatographic imaging surface, means to form a charge pattern on said imaging surface, means to develop the uncharged areas of said imaging surface comprising a polar liquid developer dispensing member located within the influence of said imaging surface having substantially the same potential as the maximum potential on said imaging surface, and means to discharge the original charged areas of said imaging surface following development to prevent the polar liquid developer from spreading into charged areas of said imaging surface.
- the imaging system of claim 1 further-including means to transfer the liquid developer from the-imaging surface to a receiving surface.
- said electrostatographic imaging surface comprises a photoconductive insulating layer and said discharge means comprises means to expose said photoconductive insulating layer to radiation of a wavelength which renders the photoconductive layer conductive.
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Wet Developing In Electrophotography (AREA)
- Color Electrophotography (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10433171A | 1971-01-06 | 1971-01-06 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3712728A true US3712728A (en) | 1973-01-23 |
Family
ID=22299929
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US00104331A Expired - Lifetime US3712728A (en) | 1971-01-06 | 1971-01-06 | Reversal development |
Country Status (9)
Country | Link |
---|---|
US (1) | US3712728A (ja) |
JP (1) | JPS5311855B1 (ja) |
BE (1) | BE777718A (ja) |
CA (1) | CA949826A (ja) |
DE (1) | DE2200423C3 (ja) |
FR (1) | FR2121328A5 (ja) |
GB (1) | GB1374831A (ja) |
IT (1) | IT946351B (ja) |
NL (1) | NL7200167A (ja) |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3830199A (en) * | 1971-03-24 | 1974-08-20 | Ricoh Kk | Device for developing an electrostatic image with a developing fluid |
US3921580A (en) * | 1974-06-12 | 1975-11-25 | Varian Associates | Liquid development of electrostatic images |
US3924945A (en) * | 1974-12-03 | 1975-12-09 | Xerox Corp | Apparatus for inductive imaging with simultaneous polar ink development |
US3972611A (en) * | 1970-03-18 | 1976-08-03 | Canon Kabushiki Kaisha | Apparatus for transferring images produced by liquid developer |
US3974554A (en) * | 1975-05-16 | 1976-08-17 | Xerox Corporation | Quadrangular trihelicoid gravure roll |
US3978817A (en) * | 1975-05-16 | 1976-09-07 | Xerox Corporation | Patterned gravure and doctoring means therefor |
US3980404A (en) * | 1974-07-26 | 1976-09-14 | Xerox Corporation | Xerographic apparatus having improved fluid dispensing member |
US3991711A (en) * | 1972-10-11 | 1976-11-16 | Fuji Xerox Co., Ltd. | Electrostatic duplicating method and apparatus utilizing wet-developing |
US4023900A (en) * | 1972-03-22 | 1977-05-17 | Xerox Corporation | Variable speed liquid development electrostatographics apparatus |
US4049344A (en) * | 1975-03-10 | 1977-09-20 | Xerox Corporation | Electrostatic imaging system |
US5177503A (en) * | 1991-05-24 | 1993-01-05 | Delphax Systems | Print system and dielectric imaging member |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1438954A (en) * | 1972-07-12 | 1976-06-09 | Waddington Ltd J | Cartons and blanks therefor |
GB2041790B (en) * | 1979-02-23 | 1983-07-27 | Savin Corp | Liquid development of electrostatic images |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3084043A (en) * | 1959-05-07 | 1963-04-02 | Xerox Corp | Liquid development of electrostatic latent images |
US3383209A (en) * | 1960-11-08 | 1968-05-14 | Gevaert Photo Prod Nv | Electrophotographic process including selective wetting by the developer liquid |
-
1971
- 1971-01-06 US US00104331A patent/US3712728A/en not_active Expired - Lifetime
- 1971-10-20 CA CA125,598A patent/CA949826A/en not_active Expired
- 1971-12-20 JP JP10357971A patent/JPS5311855B1/ja active Pending
-
1972
- 1972-01-03 GB GB12372A patent/GB1374831A/en not_active Expired
- 1972-01-05 IT IT19101/72A patent/IT946351B/it active
- 1972-01-05 BE BE777718A patent/BE777718A/xx unknown
- 1972-01-05 FR FR7201004A patent/FR2121328A5/fr not_active Expired
- 1972-01-05 DE DE2200423A patent/DE2200423C3/de not_active Expired
- 1972-01-06 NL NL7200167A patent/NL7200167A/xx not_active Application Discontinuation
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3084043A (en) * | 1959-05-07 | 1963-04-02 | Xerox Corp | Liquid development of electrostatic latent images |
US3383209A (en) * | 1960-11-08 | 1968-05-14 | Gevaert Photo Prod Nv | Electrophotographic process including selective wetting by the developer liquid |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3972611A (en) * | 1970-03-18 | 1976-08-03 | Canon Kabushiki Kaisha | Apparatus for transferring images produced by liquid developer |
US3830199A (en) * | 1971-03-24 | 1974-08-20 | Ricoh Kk | Device for developing an electrostatic image with a developing fluid |
US4023900A (en) * | 1972-03-22 | 1977-05-17 | Xerox Corporation | Variable speed liquid development electrostatographics apparatus |
US3991711A (en) * | 1972-10-11 | 1976-11-16 | Fuji Xerox Co., Ltd. | Electrostatic duplicating method and apparatus utilizing wet-developing |
US3921580A (en) * | 1974-06-12 | 1975-11-25 | Varian Associates | Liquid development of electrostatic images |
US3980404A (en) * | 1974-07-26 | 1976-09-14 | Xerox Corporation | Xerographic apparatus having improved fluid dispensing member |
US3924945A (en) * | 1974-12-03 | 1975-12-09 | Xerox Corp | Apparatus for inductive imaging with simultaneous polar ink development |
US4049344A (en) * | 1975-03-10 | 1977-09-20 | Xerox Corporation | Electrostatic imaging system |
US3974554A (en) * | 1975-05-16 | 1976-08-17 | Xerox Corporation | Quadrangular trihelicoid gravure roll |
US3978817A (en) * | 1975-05-16 | 1976-09-07 | Xerox Corporation | Patterned gravure and doctoring means therefor |
US5177503A (en) * | 1991-05-24 | 1993-01-05 | Delphax Systems | Print system and dielectric imaging member |
Also Published As
Publication number | Publication date |
---|---|
DE2200423C3 (de) | 1979-01-04 |
GB1374831A (en) | 1974-11-20 |
NL7200167A (ja) | 1972-07-10 |
DE2200423B2 (de) | 1978-05-11 |
IT946351B (it) | 1973-05-21 |
JPS5311855B1 (ja) | 1978-04-25 |
FR2121328A5 (ja) | 1972-08-18 |
CA949826A (en) | 1974-06-25 |
BE777718A (fr) | 1972-07-05 |
DE2200423A1 (de) | 1972-07-20 |
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