US3369523A - Apparatus for developing latent electrostatic images - Google Patents

Apparatus for developing latent electrostatic images Download PDF

Info

Publication number
US3369523A
US3369523A US570922A US57092266A US3369523A US 3369523 A US3369523 A US 3369523A US 570922 A US570922 A US 570922A US 57092266 A US57092266 A US 57092266A US 3369523 A US3369523 A US 3369523A
Authority
US
United States
Prior art keywords
roller
developer
image carrier
application roller
latent electrostatic
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
Application number
US570922A
Other languages
English (en)
Inventor
Naumann Gerhard
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Azoplate Corp
Original Assignee
Azoplate Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Azoplate Corp filed Critical Azoplate Corp
Application granted granted Critical
Publication of US3369523A publication Critical patent/US3369523A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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

Definitions

  • This invention relates to an apparatus, for the development of latent electrostatic images with a dispersion developer, which comprises an application roller, wiper means in engagement with the roller and defining a reservoir between itself and the periphery of the roller, means for maintaining a supply of developer liquid in the reservoir, and means for passing an image carrier past the application roller on a side of the latter opposite the wiper means whereby developer is transferred from the roller to the image carrier.
  • Dispersion developers as used in electrophotography, are fluid developers and comprise a dispersion of solid toner particles in a fluid medium having a high specific resistance and a low dielectric constant.
  • a developer of this type When a developer of this type is brought into contact with a surface electrostatically charged in the form of an image, the toner particles are attracted to the surface in accordance with the charge pattern while the dielectric fluid flows off; a visible picture is thereby produced. Positive or negative copies of the image to be reproduced can be obtained depending upon the sign of the charge of the latent electrostatic image to be developed and the sign of the charge on the dispersed particles.
  • the present invention preferably relates to an apparatus for inverse development of latent electrostatic images with dispersion developers.
  • the known devices are all suitable for positive development and some give outstanding copies. However, it is not possible to use them to produce reverse copies of satisfactory quality.
  • the non-charged parts of the image must be made visible, i.e., the dispersed toner particles must be deposited on these parts. This can, of course, be achieved only with the help of the electrostatic field generated by the charged parts of the image, This must extend as far as possible into the uncharged portions in order to obtain a suflicient deposit of toner particles.
  • the field distribution during the developing process obviously also is influenced by the components of the developing device.
  • the present invention provides apparatus for the dispersion development of latent electrostatic images which is especially suitable for reversal development.
  • This means the apparatus must be designed in such a way that the rear side of the image carrier does not come in contact with the dispersion developer and the front side should not be in direct contact with the roller material during developing.
  • the apparatus of the invention comprises an application roller, a wiper member arranged to engage the application roller to define between itself and the uppermost edge of the roller a trough-shaped reservoir, means for maintaining a supply of developer liquid in the reservoir, and means for transporting an image carrier downwardly past the lower region of the application roller on the side opposite the wiper member.
  • the arrangement is such that, during operation of the apparatus, the image carrier can be held lightly against th application roller and the latter can be driven in the same direction and at the same or approximately the same speed of movement as the image carrier, developer liquid being carried by the roller upwardly from the reservoir and over the upper edge of the roller to pass downwardly onto the image carrier, while a film of developer liquid is maintained between the surface of the application roller and the image carrier.
  • FIGURE 1 is a sectional elevation of one form of apparatus according to the invention.
  • FIGURE 2 is a similar view showing an auxiliary rinsing device.
  • the image carrier is transported, by a pair of feed rollers 6, into which it is introduced with the image side uppermost, past the developer roller 1. It is lightly supported by a guide element 8 so that the sheet is to be regarded as freely guided.
  • the now developed but still damp sheet slides over an element 10, in the form of a trough and preferably consisting of wires parallel to one another in the longitudinal direction, into a pair of take-up rollers 11 which also serve as squeezing rollers.
  • the upper roller of the pair of squeezing rollers 11 is made of polished metal.
  • the now developed and largely dried sheet is advanced by this pair of rollers onto the receiving table 12.
  • a film of developer fluid is applied to the application roller 1 by means of a wiper member 2 and a nozzle 3.
  • the wiper 2 is mounted in such a Way that a troughshaped reservoir is formed between it and the roller in which the fluid builds up in a stationary supply.
  • the wiper can be made of rubber or other rubber-like synthetic materials, felt, cloth, or similar materials resistant to wear.
  • the wiper is preferably rectangular and of a height of -20 mm.
  • the nozzle 3 sprays the dispersion developer into the gap 4 already mentioned.
  • the developer is fed to the nozzle through a pipe 5, from a storage container, not shown, by a pump, also not shown.
  • the nozzle can be a slot nozzle or a tube with a number of small holes.
  • the pressure which is regulated by the pumping rate, should be set so that the developer fluid does not foam in the reservoir 4.
  • a small pool of developer fluid is formed in the reservoir 4, part of it being continually carried away by the application roller.
  • the part of the fluid film which is not transmitted to the image carrier is held back by the wiper 2 and flows into the container 9 whence it passes to the storage container already mentioned but not shown.
  • the greater part of the fluid sprayed into the reservoir 4 flows to the two ends thereof and over the end surfaces of the application roller to be caught also in the container 9.
  • the application roller can be made of any metal. The best are brass, chromed brass or high-grade steel, as these materials easily can be given a high quality surface finish.
  • the diameter of the application roller can be between 20 and 100 mm. Smaller or larger diameters are also possible under certain conditions.
  • the width of the roller can be of any desired magnitude subject to structural requirements and is limited only by the tendency of the roller to bend under its own weight. However, this tendency is insignificant in rollers of the widths used in practice.
  • the peripheral speed of the application roller should be at least 2 m. per minute and should not exceed 25 m. per minute. At lesser and greater speeds the quality of the copies is considerably reduced.
  • the purpose of the guide element 8 is to support the image carrier from the rear during developing.
  • the form of the guide element 8 is not critical. All that the element has to do is to ensure that the copy material arriving approximately tangentially to the application roller is guided in a slight curve without being pressed hard against the roller.
  • a curved sheet of metal with the same curvature as the application roller over at least part of it can be used as the guide element.
  • the form of guide element shown in FIGURE 1 is particularly advantageous and therefore is preferred.
  • a sheet of metal bent in two places is mounted in such a way that the edges 8a and 812 form two guide rails parallel to the roller.
  • the distance of the edges from the roller can be between 2 and 20 mm. It is not necessary for both edges to be at the same distance from the roller. It is even possible to use only a strip of metal, the front edge of which is parallel to the axis of the application roller.
  • the image be rinsed with the pure dispersion medium after the developer has been applied and before the excess developer is squeezed off. Provided this rinsing is carried out in the dark, developer particles adhering to the background will be washed off while the developer will continue to adhere to the required parts of the image.
  • Fluid hydrocarbons or fluid halogenated hydrocarbons generally are used as the dispersion medium. The rinsing can be carried out simply by immersing the just-developed image in the pure dispersion medium. However, this method is not particularly successful and it is preferable to carry out rinsing with a moving fluid. A device such as that shown in FIGURE 2 is particularly advantageous for this.
  • a metal roller 13 rotating in the direction of motion of the image carrier is mounted at a small distance above the element 10 over which the carrier slides.
  • a nozzle 14 for spraying the pure dispersion medium In front of the roller in the direction of motion of the image carrier is a nozzle 14 for spraying the pure dispersion medium, the spray being incident both on the image just developed and on the roller 13.
  • the fluid flowing to the sides and over the ends of the sheet is collected in the funnel 15 and fed back to the spraying nozzle 14 by way of a pump and a storage container, not shown.
  • An apparatus for the development of latent electrostatic images with a dispersion developer which comprises an application roller, wiper means in engagement with the roller and defining a trough-shaped reservoir between itself and the periphery of an upper portion of the roller, means for maintaining a supply of developer liquid in the reservoir, and means for passing an image carrier downwardly past a lower portion of the application roller on a side of the latter opposite the wiper means whereby the image carrier is held lightly against the application roller while the latter rotates in the same direction and at substantially the same speed of movement as the image carrier, the developer liquid being carried by the roller upwardly from the reservoir and over the top of the roller to pass downwardly onto the image carrier, and a film of developer liquid being maintained between the surface of the application roller and the image carrier.
  • An apparatus in which the means for passing an image carrier past the application roller comprises a pair of feed rolls and guide means to hold the image carrier against the application roller.
  • An apparatus including a pair of squeeze rolls through which the image carrier is passed after development.
  • An apparatus in which the means for maintaining a supply of developer liquid in the reservoir includes nozzle means.
  • An apparatus including means for rinsing the image carrier after development.
  • guide means has one guide edge parallel to the axis of the 15 P.
  • FELDMAN Assistant Examiner.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Wet Developing In Electrophotography (AREA)
US570922A 1965-08-11 1966-08-08 Apparatus for developing latent electrostatic images Expired - Lifetime US3369523A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEK0056856 1965-08-11

Publications (1)

Publication Number Publication Date
US3369523A true US3369523A (en) 1968-02-20

Family

ID=7228033

Family Applications (1)

Application Number Title Priority Date Filing Date
US570922A Expired - Lifetime US3369523A (en) 1965-08-11 1966-08-08 Apparatus for developing latent electrostatic images

Country Status (9)

Country Link
US (1) US3369523A (de)
AT (1) AT267326B (de)
BE (1) BE685294A (de)
CH (1) CH440979A (de)
DE (1) DE1497165B2 (de)
ES (1) ES330025A1 (de)
FR (1) FR1489370A (de)
GB (1) GB1149354A (de)
NL (1) NL153341B (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3453138A (en) * 1966-07-27 1969-07-01 Polaroid Corp Photographic processing apparatus and method
US3500793A (en) * 1967-10-30 1970-03-17 Bell & Howell Co Developer roller coating means and guide for electrostatic copying machine
US3766887A (en) * 1970-01-08 1973-10-23 Fuji Photo Film Co Ltd Developing device for electrostatic latent image
US3908594A (en) * 1972-04-03 1975-09-30 Fuji Photo Film Co Ltd Marking apparatus
US4720731A (en) * 1985-06-17 1988-01-19 Ricoh Company, Ltd. Device for supplying developing solution

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU468028B2 (en) * 1972-03-27 1975-12-18 Moore Business Forms Inc Method of and means for rapid development of electrostatic images

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2842092A (en) * 1955-03-02 1958-07-08 John Waldron Corp Reverse roll coating machine with blade support for web
US2953476A (en) * 1952-12-18 1960-09-20 British Cotton Ind Res Assoc Treatment of yarns and the like with liquids
US3010845A (en) * 1957-05-15 1961-11-28 Goodrich Co B F Method and apparatus for decorating web or sheet material with glitter
US3124484A (en) * 1964-03-10 magnusson
US3169887A (en) * 1961-05-04 1965-02-16 Eastman Kodak Co Electrophotographic developing apparatus
US3220339A (en) * 1962-09-28 1965-11-30 Bird Machine Co Chemical and water box for paper making machinery
US3249088A (en) * 1963-04-03 1966-05-03 Scm Corp Developing tank unit for electrostatic printing
US3276424A (en) * 1962-06-22 1966-10-04 Azoplate Corp Process and apparatus for the development of latent electrostatic images
US3307466A (en) * 1963-05-27 1967-03-07 Fuji Photo Film Co Ltd Device for applying a treating solution to sensitized paper

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3124484A (en) * 1964-03-10 magnusson
US2953476A (en) * 1952-12-18 1960-09-20 British Cotton Ind Res Assoc Treatment of yarns and the like with liquids
US2842092A (en) * 1955-03-02 1958-07-08 John Waldron Corp Reverse roll coating machine with blade support for web
US3010845A (en) * 1957-05-15 1961-11-28 Goodrich Co B F Method and apparatus for decorating web or sheet material with glitter
US3169887A (en) * 1961-05-04 1965-02-16 Eastman Kodak Co Electrophotographic developing apparatus
US3276424A (en) * 1962-06-22 1966-10-04 Azoplate Corp Process and apparatus for the development of latent electrostatic images
US3220339A (en) * 1962-09-28 1965-11-30 Bird Machine Co Chemical and water box for paper making machinery
US3249088A (en) * 1963-04-03 1966-05-03 Scm Corp Developing tank unit for electrostatic printing
US3307466A (en) * 1963-05-27 1967-03-07 Fuji Photo Film Co Ltd Device for applying a treating solution to sensitized paper

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3453138A (en) * 1966-07-27 1969-07-01 Polaroid Corp Photographic processing apparatus and method
US3500793A (en) * 1967-10-30 1970-03-17 Bell & Howell Co Developer roller coating means and guide for electrostatic copying machine
US3766887A (en) * 1970-01-08 1973-10-23 Fuji Photo Film Co Ltd Developing device for electrostatic latent image
US3908594A (en) * 1972-04-03 1975-09-30 Fuji Photo Film Co Ltd Marking apparatus
US4720731A (en) * 1985-06-17 1988-01-19 Ricoh Company, Ltd. Device for supplying developing solution

Also Published As

Publication number Publication date
CH440979A (de) 1967-07-31
BE685294A (de) 1967-02-09
AT267326B (de) 1968-12-27
NL153341B (nl) 1977-05-16
GB1149354A (en) 1969-04-23
NL6610805A (de) 1967-02-13
ES330025A1 (es) 1967-06-16
FR1489370A (fr) 1967-07-21
DE1497165A1 (de) 1969-04-17
DE1497165B2 (de) 1971-11-18

Similar Documents

Publication Publication Date Title
US3781107A (en) Cleaning apparatus
US3368526A (en) Apparatus for developing electrostatic latent images by liquid developing system
CA1144821A (en) Method and apparatus for liquid-developing latent electrostatic images
US3669073A (en) Electrostatic developing system
US3407786A (en) Applicator device
US3572288A (en) Development apparatus
US3405683A (en) Apparatus for the development of latent electrostatic images
US3941469A (en) Dry type developing device for a copying apparatus or like apparatus
US3752119A (en) Liquid toner applicator
US3384051A (en) Electrostatic liquid developer system
US3687708A (en) Liquid development of latent electrostatic images
US3369523A (en) Apparatus for developing latent electrostatic images
US4342823A (en) Perforate development electrode
US3375806A (en) Xerographic donor development apparatus
US3999511A (en) Apparatus for developing electrophotographic materials
US3124484A (en) magnusson
US4466728A (en) Device for the development of charge images, which are arranged on a charge image carrier, with the aid of a developing mixture consisting of toner and carrier particles
US3672326A (en) Method and apparatus for applying liquid developer to copy sheets
US3654896A (en) Apparatus for developing electrostatic images
JPH05204252A (ja) 移動ベルト液体現像方法及び装置
JPH0342469B2 (de)
US2876737A (en) Apparatus for developing electrostatic images on sheet material
US3333572A (en) Electrostatic printing
US3750624A (en) Apparatus for developing electrophotographic continuous web material
US4883018A (en) Liquid ink development system