US3654896A - Apparatus for developing electrostatic images - Google Patents

Apparatus for developing electrostatic images Download PDF

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Publication number
US3654896A
US3654896A US573294A US3654896DA US3654896A US 3654896 A US3654896 A US 3654896A US 573294 A US573294 A US 573294A US 3654896D A US3654896D A US 3654896DA US 3654896 A US3654896 A US 3654896A
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US
United States
Prior art keywords
spray
developer
image carrier
fluid
curtain
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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US573294A
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English (en)
Inventor
Gerhard Marx
Hans Heist
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.)
Kalle GmbH and Co KG
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Kalle GmbH and Co KG
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Filing date
Publication date
Application filed by Kalle GmbH and Co KG filed Critical Kalle GmbH and Co KG
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Publication of US3654896A publication Critical patent/US3654896A/en
Anticipated expiration legal-status Critical
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    • 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
    • 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
    • Y10S118/00—Coating apparatus
    • Y10S118/04—Curtain coater

Definitions

  • the electrophotographic material In the case of older, known methods for developing latent electrostatic images with dispersion developers, the electrophotographic material generally is brought into contact with the developer by immersing it or drawing it through a container holding developer fluid.
  • the known devices are suitable for positive development and some give outstanding positive copies. However, they can not be used to produce reverse copies of a satisfactory quality.
  • the uncharged portions of the image-bearing surface must be made visible, i.e. the dispersed toner agent must be deposited on them. Naturally this can be achieved only by means of the field generated by the charged portions. This field must exert an influence as far as possible into the uncharged portions so that sufficient deposition of the toner can take place.
  • the field distribution during the developing process obviously is also influenced by the components of the developing apparatus. However, it is scarcely possible to make theoretical statements as to how the developing apparatus should be constructed to achieve optimum reversal development because of the complexity of the matter.
  • the present invention provides an apparatus for developing latent electrostatic images by means of a dispersion developer, wherein material to be developed is passed, with the imagebearing surface downwards, over an upwardly directed spray of developer fluid, and, after development, the surplus developer fluid is removed, a jet of developer spray being directed, in the form of a curtain of fluid at least as wide as the material to be developed and of substantially uniform height over the relevant area.
  • the jet has such an angle to the vertical that, when unimpeded, the spray curtain assumes, under the influence of gravity, a parabolic trajectory, and the spray pressure is so controlled that the trajectory is maintained substantially constant and of such a height that the material under development can be located in the spray curtain at a distance of between 10 and mm. below the highest point of the trajectory, the material being thus located during the development.
  • the pressure range is most easily defined by the difference in height between the highest point of the undisturbed fluid trajectory and the path of the copying material in the zone of application. If the difference in height is below the given range, the pressure is too small. The print then will be only partially developed and edge effects easily occur. If the difference in height is larger, the pressure is too great and the toner will be lightly deposited on the background where there is no image, so that the quality of the copies will be reduced by background. If the electric field from the print is strong, the pressure should be maintained towards the lower limit of the given range. Conversely, a pressure towards the upper limit of the range should be chosen if the electric field is weak.
  • the quantity of developer fluid available to the latent electrostatic image to be developed must be such that sufficient blackening of the print is achieved. This is generally the case when about 5-50 ml. of dispersion are available per dcm. of surface of the print carrier. Entirely satisfactory copies, however, can be obtained with smaller or larger quantities since the speed of developing depends not only upon the available quantity of developer but also upon the nature and composition of the dispersion.
  • the thickness of the rising film at the height of the plane of motion of the copying material, measured in the undisturbed curtain of fluid, is preferably between 0.5 and 2 mm.
  • a contact zone between the fluid and the film surface is formed which is in this case 1-3 cm. wide; development takes place in this zone.
  • Nozzles that can be more easily produced than wide slot nozzles comprise a tube with one or more straight rows of perforations. Small, individual sprays thus emerge from each hole. The individual sprays merge to form a more or less continuous curtain of fluid only at a certain distance from their exit positions. Even in this case the pressure is not uniform throughout; it falls slightly between the centers of the individual jets. If only one row of holes is used, this drop in the pressure can be detected by longitudinal stripes on the copy.
  • the stripes correspond to the distance between the holes.
  • the diameter of the holes in the tubes can be about 0.2 to 2 mm. Smaller holes are somewhat less desirable since the pressure head then is correspondingly large.
  • the lower roller of the pair of rollers 5 While the copying material runs through, the lower roller of the pair of rollers 5 is kept moistened by the squeezed out dispersion medium flowing back. With some kinds of toners this dampening is not sufficient to reliably ensure that the image of one print is not imprinted on a subsequent one. In these cases, it has proved successful to flush the pair of rollers 5, preferably the lower roller, with developer when the apparatus is running empty.
  • This can be achieved by an appropriate shape of the deflector plate 9, by tilting the entire apparatus in the direction of motion of the copy material, or simply by positioning the elements of the apparatus in such a way that the plane through the lines of contact of the pairs of rollers 3 and 5 is inclined at 45 to the horizontal in the direction of motion of the print carrier. In this case, part of the developer flowing from the deflector plate 9 continuously flows onto the lower roller of the pair of rollers 5.
  • the time lag between the end of the sheet passing the switch 20 and the final switching-off of the apparatus is determined according to the length of the printing path and the speed with which the sheet moves. The times can be set to any value by a time lag relay.
  • the switch 20 actuates the air nozzle 23 at the same time as the suction devices.
  • the air nozzle is suitably connected to the pressure side of the air pump, not shown. A strongly convergent air stream with a high velocity leaves the air nozzle and impinges on the excess developer fluid adhering to the copy sheet moving above the nozzle, causing such fluid to fall off in drops.
  • the fluid drips into the funnel 18 which also acts as a cover for the container 17.
  • the pump 16 for feeding the dispersion developer.
  • FIG. 6 shows an apparatus similar to that of FIG. 1 in which the path of the image carrier is inclined downwardly in the direction of movement of the image carrier. The operation of this embodiment is as described above in connection with FIG. 1.
  • An apparatus for developing latent electrostatic images with a dispersion developer which comprises means for moving an image carrier along a predetermined path, spray means extending across the path for producing only an upwardly directed freely-formed laminar flow spray curtain adapted to impinge on the image carrier at an angle between 10 and 45 to the vertical and in the direction of motion of the image car rier at a distance between 10 and mm. below the highest point of the uninterrupted spray curtain, pump means for maintaining a supply of developer liquid to the spray means, and means for removing excess developer from the developed image carrier.
  • the spray means includes a nozzle having a continuous slot with a width between 0.1 and 2.0 mm.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Wet Developing In Electrophotography (AREA)
  • Dry Development In Electrophotography (AREA)
US573294A 1965-08-21 1966-08-18 Apparatus for developing electrostatic images Expired - Lifetime US3654896A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEK0056946 1965-08-21

Publications (1)

Publication Number Publication Date
US3654896A true US3654896A (en) 1972-04-11

Family

ID=7228066

Family Applications (1)

Application Number Title Priority Date Filing Date
US573294A Expired - Lifetime US3654896A (en) 1965-08-21 1966-08-18 Apparatus for developing electrostatic images

Country Status (10)

Country Link
US (1) US3654896A (de)
AT (1) AT267327B (de)
BE (1) BE685765A (de)
CH (1) CH447815A (de)
DE (1) DE1497166B2 (de)
ES (1) ES330402A1 (de)
FR (1) FR1490096A (de)
GB (1) GB1144890A (de)
NL (1) NL155667B (de)
SE (1) SE318783B (de)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3844820A (en) * 1972-08-09 1974-10-29 Bethlehem Steel Corp Method of applying a coating to both sides of a moving strip
US3916460A (en) * 1974-12-30 1975-11-04 Dow Chemical Co Sofa bed and mechanism therefor
US4032073A (en) * 1974-06-13 1977-06-28 Ragnar Jakob Aaltonen Apparatus including a pump mixer for coating objects
US4148274A (en) * 1974-10-15 1979-04-10 Agfa-Gevaert N.V. Processing apparatus
US4267795A (en) * 1980-05-09 1981-05-19 Crown Zellerbach Corporation Liquid distributing apparatus
US4324820A (en) * 1980-07-18 1982-04-13 St. Regis Paper Company Method and apparatus for coating a paper web
WO1997012289A1 (en) * 1995-09-26 1997-04-03 Minnesota Mining And Manufacturing Company Method and apparatus for applying liquid toner to a print medium
US5915152A (en) * 1995-03-23 1999-06-22 Indigo N.V. Imaging device having liquid toner applicator using a nozzle
US6093248A (en) * 1996-02-21 2000-07-25 Voith Sulzer Papiermaschinen Gmbh Apparatus for applying a liquid or pasty medium onto a traveling material web

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB255578A (en) * 1925-05-12 1926-07-29 Richard Jaretzki Improvements in and relating to the production of sound records
US2419132A (en) * 1945-01-18 1947-04-15 Murray J Friedman Apparatus for treating sheet material
US2487440A (en) * 1944-04-27 1949-11-08 Promag A G Moistening device for envelope flaps
US3141793A (en) * 1959-09-09 1964-07-21 Australia Res Lab Apparatus for coating surfaces
US3144211A (en) * 1962-08-06 1964-08-11 Goldman Percy Water sweeper attachment for garden hose
US3192846A (en) * 1961-08-22 1965-07-06 Itek Corp Data processing apparatus
US3202526A (en) * 1961-10-05 1965-08-24 Scm Corp Method and apparatus for liquid development of latent images
US3237871A (en) * 1963-03-14 1966-03-01 L A B Static liquid atomizer
US3334613A (en) * 1964-10-28 1967-08-08 Xerox Corp Xerographic development apparatus
US3405627A (en) * 1965-08-17 1968-10-15 Itek Corp Film processor

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB255578A (en) * 1925-05-12 1926-07-29 Richard Jaretzki Improvements in and relating to the production of sound records
US2487440A (en) * 1944-04-27 1949-11-08 Promag A G Moistening device for envelope flaps
US2419132A (en) * 1945-01-18 1947-04-15 Murray J Friedman Apparatus for treating sheet material
US3141793A (en) * 1959-09-09 1964-07-21 Australia Res Lab Apparatus for coating surfaces
US3192846A (en) * 1961-08-22 1965-07-06 Itek Corp Data processing apparatus
US3202526A (en) * 1961-10-05 1965-08-24 Scm Corp Method and apparatus for liquid development of latent images
US3144211A (en) * 1962-08-06 1964-08-11 Goldman Percy Water sweeper attachment for garden hose
US3237871A (en) * 1963-03-14 1966-03-01 L A B Static liquid atomizer
US3334613A (en) * 1964-10-28 1967-08-08 Xerox Corp Xerographic development apparatus
US3405627A (en) * 1965-08-17 1968-10-15 Itek Corp Film processor

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3844820A (en) * 1972-08-09 1974-10-29 Bethlehem Steel Corp Method of applying a coating to both sides of a moving strip
US4032073A (en) * 1974-06-13 1977-06-28 Ragnar Jakob Aaltonen Apparatus including a pump mixer for coating objects
US4148274A (en) * 1974-10-15 1979-04-10 Agfa-Gevaert N.V. Processing apparatus
US3916460A (en) * 1974-12-30 1975-11-04 Dow Chemical Co Sofa bed and mechanism therefor
US4267795A (en) * 1980-05-09 1981-05-19 Crown Zellerbach Corporation Liquid distributing apparatus
US4324820A (en) * 1980-07-18 1982-04-13 St. Regis Paper Company Method and apparatus for coating a paper web
US5915152A (en) * 1995-03-23 1999-06-22 Indigo N.V. Imaging device having liquid toner applicator using a nozzle
WO1997012289A1 (en) * 1995-09-26 1997-04-03 Minnesota Mining And Manufacturing Company Method and apparatus for applying liquid toner to a print medium
US5701561A (en) * 1995-09-26 1997-12-23 Minnesota Mining And Manufacturing Company Method and apparatus for applying liquid toner to a print medium using multiple toner applicators for each liquid toner
US6093248A (en) * 1996-02-21 2000-07-25 Voith Sulzer Papiermaschinen Gmbh Apparatus for applying a liquid or pasty medium onto a traveling material web

Also Published As

Publication number Publication date
DE1497166A1 (de) 1969-05-08
SE318783B (de) 1969-12-15
NL155667B (nl) 1978-01-16
GB1144890A (en) 1969-03-12
AT267327B (de) 1968-12-27
CH447815A (de) 1967-11-30
FR1490096A (fr) 1967-07-28
ES330402A1 (es) 1967-06-16
BE685765A (de) 1967-02-20
NL6611306A (de) 1967-02-22
DE1497166B2 (de) 1972-02-24

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