US3511214A - Cascade developing mechanism for electrography - Google Patents

Cascade developing mechanism for electrography Download PDF

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Publication number
US3511214A
US3511214A US712852A US3511214DA US3511214A US 3511214 A US3511214 A US 3511214A US 712852 A US712852 A US 712852A US 3511214D A US3511214D A US 3511214DA US 3511214 A US3511214 A US 3511214A
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United States
Prior art keywords
developer
cascade
plate
image
electrography
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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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US712852A
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English (en)
Inventor
Howard T Hodges
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.)
Eastman Kodak Co
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Eastman Kodak Co
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Publication date
Application filed by Eastman Kodak Co filed Critical Eastman Kodak Co
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Publication of US3511214A publication Critical patent/US3511214A/en
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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
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/0801—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer for cascading

Definitions

  • This invention relates to the field of electrography and, more specifically, to cascade developing mechanisms for toning electrostatic images (which term is meant to include any electrostatic charge pattern regardless of method of formation).
  • an electrostatic image is formed on an insulating surface, and that image is developed by contacting it with finely divided toner particles, generally of opposite polarity to the image, giving a toner image defined by the electrostatic image. This image is then utilized, for example, by transferring it to a receiving surface and heating it until fixed.
  • the electrostatic image is formed by imagewise exposing a charged photoconductive layer to actinic radiation, thereby dissipating charge in the areas exposed, leaving an electrostatic image corresponding to the unexposed areas of charge.
  • a commonly used mechanism involves an ordinary bucket conveyor.
  • the developer falls from the charge-bearing surface into a bin in which buckets dip.
  • the buckets carry the developer to the top of the mechanism where the buckets empty either into a hopper or 3,51 1,214 Patented May 12, 1970 directly onto the image-bearing surface.
  • the development station must be quite long in a direction of the moving charge-bearing surface. If a bucket-type recirculating system is added with a substantial bin for collection of developer, other dimensions of the station also become quite substantial.
  • a cascade developing station may be one of the largest single portions of an electrographic machine.
  • a more compact recirculating mechanism is provided for cascade systems.
  • the prime feature of the mechanism is a stepped surface which is oscillated to propel developer up an incline. This surface can be inclined at the same angle as the charge-bearing surface, and positioned at very close proximity with it, thereby adding compactness to the system.
  • the stepped surface can be on a plate constructed of conducting material which plate then performs a secondary function as a development electrode.
  • FIG. 1 is a schematic side view of a development apparatus constructed according to the invention
  • FIG. 2 is a perspective view of a portion of the apparatus shown in FIG. 1;
  • FIG. 3 is a schematic side view of another embodiment of the invention.
  • an electrostatic image-bearing surface 1 is moved through a path, a portion of which is inclined to receive cascade developer.
  • Developer is collected in a reservoir 7 which is inclined toward a feed slot 10 from which developer falls onto a lower portion of a stepped surface 3 of a plate 2.
  • the plate 2 is mounted for oscillation with flexure members 4 and 5 which are connected to a housing 11.
  • an oscillating driver '6 oscillates plate 2 back and forth in a direction generally parallel to the plate incline.
  • the surface 3 is shaped to inhibit motion of developer in a downward direction but to allow motion upward. This is accomplished [by ratchet-like steps in the surface 3. With these steps, as the plate 2 is moved by the oscillating driver 6 in a direction generally up the incline, the developer is propelled by the steps in that direction. The steps are shaped to allow this movement. When the plate is moved in the opposite direction, developer motion relative to the surface 3 continues to be up the plate until gravity overcomes this motion. The shape of the steps then inhibits the developer from movement down the plate.
  • the developer will be propelled step-bystep up the plate until it reaches a cascade feed position at the top 12 of the plate from which it spills onto the image-bearing surface 1.
  • the developer cascades across the surface 1 toning the image and then falls onto a surface 9 inclined toward the reservoir 7 to return developer for reuse.
  • a reservoir can be used which feeds developer directly to the recirculation means thereby eliminating a large bin used in prior devices.
  • a large portion of the recirculation mechanism is only as thick as the plate 2, and, therefore, can be compactly positioned in a machine.
  • top 12 of the plate 1 is shown as the feed position for cascade developer, more uniform discharge of cascade developer onto the image bearing surface 1 can be obtained by discharging developer from oscillating plate 2 into a hopper, not shown, which be comes the feed position, from which developer is fed onto surface 1.
  • toner dispensers well known in the art, for example, a toner dispenser 13 shown schematically in FIG. 1 discharging toner into the reservoir 7.
  • a simple back-and-forth oscillating movement is not the only motion suitable for operation. Other repetitive motions will work.
  • a drive belt 14 moves eccentric drives 15 and 16 to move the plate 2 through a generally orbitable path. Movement of developer up the incline is primarily effected by the vector of the orbital motion which is parallel to the incline and directed up the incline, but also some of the movement in a direction away from the incline aids in propelling the developer over the apex of the next step.
  • the plate 2 may be positioned parallel to the surface 1 and may be constructed of a conductive material in order to also serve a secondary function as a development electrode. In serving this function, the plate may be insulated from ground, connected to an electrical bias or connected to ground to accomplish a variety of results well known in the art. In FIG. 1, the plate is shown connected to a source 17 of electrical bias.
  • the invention has been described in its application to a moving flexible, charge-carrying surface which can be moved through a path having a long, straight incline, in which application the invention givesits most striking advantages.
  • it can also be used with other shapes of surfaces, for example, cylindrically shaped chargebearing surfaces.
  • a mechanism for returning said developer to said cascade feed position comprising:
  • a member having an inclined surface running from said reservoir to said feed position and shaped to transport developer up said surface in res onse to reciprocating motion of said surface, said member having a portion which is electrically conductive and closely spaced to said image-bearing surface, and
  • a mechanism for mixing components of said developer and returning said developer to said cascade feed position comprising:
  • a member having an inclined surface extending from said reservoir to said feed position and shaped (a) to inhibit movement of cascade developer down said surface
  • said means for imparting motion includes an eccentric drive means coupled to said surface for imparting orbital motion to said surface while maintaining the inclination of said surface.
  • a cascade developing mechanism comprising:
  • developer reservoir means having developer feed means
  • an elongated plate mounted for oscillatory movement, inclined at approximately said angle and closely spaced to said moving charge-bearing surface, at least a portion of said plate close to said charge bearing surface being electrically conductive and connectable to a source of electrical potential to serve as a development electrode during application of developer to said image-bearing surface.
  • an upper surface of said plate being positioned to receive developer from said developer feed means and shaped to inhibit movement of cascade developer down said surface, to allow movement of developer up said surface and to impart movement to cascade developer resting on said surface in a direction up said surface when said plate is oscillated, and
  • said reservoir means includes means for receiving developer after it falls from said image-carrying Web including gravity return means for directing said developer to said means, and
  • said feed means includes a slot in said gravity return means which allows developer to fall onto the lower portion of said incline plate.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Dry Development In Electrophotography (AREA)
US712852A 1968-03-13 1968-03-13 Cascade developing mechanism for electrography Expired - Lifetime US3511214A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US71285268A 1968-03-13 1968-03-13

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US3511214A true US3511214A (en) 1970-05-12

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US712852A Expired - Lifetime US3511214A (en) 1968-03-13 1968-03-13 Cascade developing mechanism for electrography

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US (1) US3511214A (enrdf_load_stackoverflow)
DE (1) DE1912586A1 (enrdf_load_stackoverflow)
FR (1) FR2003798A1 (enrdf_load_stackoverflow)
GB (1) GB1265815A (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3639050A (en) * 1969-01-22 1972-02-01 Itt Particle-applicating device
US3702108A (en) * 1969-11-12 1972-11-07 Eastman Kodak Co Image development station
US3797457A (en) * 1970-03-06 1974-03-19 R Bushnell Coating of surfaces with powder
US4794878A (en) * 1987-08-03 1989-01-03 Xerox Corporation Ultrasonics traveling wave for toner transport

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US218757A (en) * 1879-08-19 Improvement in sawdust-conveyers
US1720131A (en) * 1926-01-25 1929-07-09 Line Material Co Conveyer and tumbler for article-coating apparatus
US2618376A (en) * 1950-10-03 1952-11-18 Jr Arthur E May Material conveying toy
US3332328A (en) * 1965-03-01 1967-07-25 Xerox Corp Xerographic developer seal and process
US3367307A (en) * 1965-06-02 1968-02-06 Arlside Ltd Electrostatographic developing apparatus

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US218757A (en) * 1879-08-19 Improvement in sawdust-conveyers
US1720131A (en) * 1926-01-25 1929-07-09 Line Material Co Conveyer and tumbler for article-coating apparatus
US2618376A (en) * 1950-10-03 1952-11-18 Jr Arthur E May Material conveying toy
US3332328A (en) * 1965-03-01 1967-07-25 Xerox Corp Xerographic developer seal and process
US3367307A (en) * 1965-06-02 1968-02-06 Arlside Ltd Electrostatographic developing apparatus

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3639050A (en) * 1969-01-22 1972-02-01 Itt Particle-applicating device
US3702108A (en) * 1969-11-12 1972-11-07 Eastman Kodak Co Image development station
US3797457A (en) * 1970-03-06 1974-03-19 R Bushnell Coating of surfaces with powder
US4794878A (en) * 1987-08-03 1989-01-03 Xerox Corporation Ultrasonics traveling wave for toner transport

Also Published As

Publication number Publication date
GB1265815A (enrdf_load_stackoverflow) 1972-03-08
DE1912586A1 (de) 1969-10-09
FR2003798A1 (enrdf_load_stackoverflow) 1969-11-14

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