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US4600290A Expired / Lapsed US ⏱️ 0.0 years remaining

Magnetic brush/stationary electrode development system

Assignee: Ricoh Co Ltd
•
Filing: 1985-07-15
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Granted: 1986-07-15
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Expires: 2005-07-15
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Abstract

Abstract An electrophotographic copying apparatus is disclosed, including a first rotating cylindrical electrode positioned above the lowest point of rotation of the photoconductive surface and closely adjacent that surface. This first electrode is suitably biased to form a brush of toner which, as the brush rotates with the direction of the travel of the image, develops the image. A second rotating cylindrical electrode is positioned at the low point of travel of the latent image surface; the brush formed on the surface of this electrode as the electrode rotates against the direction of travel of the image, develops the trailing edges of the image. A biased electrode plate extends from the upper electrode to a point near to the lowest electrode. As toner material is supplied to the first rotating electrode, it is carried over the surface of this electrode and flows down through the development path defined by the electrode plate and the rotating drum surface to develop the latent image. A gap is formed between the lower point of the plate and the rotating electrode so that unused carrier may fall away from the surface of the rotating drum and into the sump which is defined in the bottom of the housing. A third roller is located further along the development path and above the second roller and rotates against the direction of travel of the photoconductive surface. This roller is used primarily for cleaning. A second plate electrode extends from this third roller substantially down to a point closely adjacent the second rotating electrode. Toner material flows over the surface of the third electrode and down through this gap defined by the second plate electrode and the moving latent image surface. The development in this region supplements the development action of the second roller.

Inventors

  • 👤 Steven R. Ungemach

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 12:09
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/0801; G03G15/095; G03G2215/00; G03G2215/06; G03G2215/0602; G03G2215/0604; G03G2215/0624; G03G2215/0634; G03G2215/0636; G03G2215/0648

Claims Analysis

Total Claims: 13
Claim 1
Independent Claim 47 words
In an electrophotographic copying apparatus for developing electrostatic latent images on a photosensitive outer surface of a rotating developing drum, the drum being moved through a development zone in contact with a cascading flow of two-component developer material to develop the latent electrostatic image, the apparatus including:
Claim 2
Dependent Claim 47 words
In an electrophotographic copying apparatus for developing electrostatic latent images on a photosensitive outer surface of a rotating developing drum, the drum being moved through a development zone in contact with a cascading flow of two-component developer material to develop the latent electrostatic image, the apparatus including:
Claim 3
Dependent Claim 144 words
(a) a sump containing a supply of developing material including electrically charged toner particles displaying the opposite electrostatic polarity of said image, (b) a first cylindrical electrode supported for rotation in the direction of movement of said surface; (c) a first bias supply for forming a brush on the surface of said electrode for developing said image, said first electrode being located close enough to the surface of the drum to brush the surface and thereby develop said images, (d) a second cylindrical electrode supported for rotation opposite the direction of movement of said surface, (e) a second bias supply means for forming a brush of toner material on the surface of said second electrode for developing the images, said second electrode being located sufficiently close to said surface of said drum to brush the surface and develop the trailing edges of said images,
Claim 4
Dependent Claim 144 words
(a) a sump containing a supply of developing material including electrically charged toner particles displaying the opposite electrostatic polarity of said image, (b) a first cylindrical electrode supported for rotation in the direction of movement of said surface; (c) a first bias supply for forming a brush on the surface of said electrode for developing said image, said first electrode being located close enough to the surface of the drum to brush the surface and thereby develop said images, (d) a second cylindrical electrode supported for rotation opposite the direction of movement of said surface, (e) a second bias supply means for forming a brush of toner material on the surface of said second electrode for developing the images, said second electrode being located sufficiently close to said surface of said drum to brush the surface and develop the trailing edges of said images,
Claim 5
Dependent Claim 63 words
(f) a plate electrode extending parallel to said drum between said first and second electrodes, (g) a third bias supply for biasing said plate electrode to supplement the development of said images, and (h) means for directing a supply of toner material over said first cylindrical electrode and along a path between said plate electrode and said drum to develop said latent images.
Claim 6
Dependent Claim 63 words
(f) a plate electrode extending parallel to said drum between said first and second electrodes, (g) a third bias supply for biasing said plate electrode to supplement the development of said images, and (h) means for directing a supply of toner material over said first cylindrical electrode and along a path between said plate electrode and said drum to develop said latent images.
Claim 7
Dependent Claim 50 words
Apparatus as claimed in claim 1 wherein said plate electrode extends from a position closely adjacent said first electrode to a point spaced from said second electrode, the spacing between the plate electrode and the second cylindrical electrode defining an opening for allowing the toner to fall into the sump.
Claim 8
Dependent Claim 34 words
Apparatus as claimed in claim 2 further comprising a plate adjacent the space between the plate and second cylindrical electrodes to limit the amount of toner reaching the second electrode along said toner path.
Claim 9
Dependent Claim 27 words
An assembly as claimed in claim 3 further comprising a doctor blade adjacent the second electrode for limiting the size of the brush formed on the electrode.
Claim 10
Dependent Claim 22 words
An assembly as claimed in claim 2 comprising a third cylindrical electrode rotating against the direction of movement of said photoconductor surface.
Claim 11
Dependent Claim 33 words
An assembly as claimed in claim 5 further comprising means for applying a bias potential to said third roller relative to the background potential of said latent image to clean said photoconductive surface.
Claim 12
Dependent Claim 35 words
An assembly as claimed in claim 6 further comprising a second plate electrode located adjacent said moving surface between said second and third cylindrical electrodes, said electrode being biased to facilitate cleaning of said drum.
Claim 13
Dependent Claim 18 words
Apparatus as claimed in claim 7 wherein said second electrode is of lesser extent than said first electrode.

References Cited (Backward Citations)

US3472657A Cited
US4007707A Cited
US4113371A Cited
US4131357A Cited
US4264185A Cited
US4466728A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1989-07-14 1990-01-13 1990-07-15 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1993-07-14 1994-01-13 1994-07-15 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1997-07-14 1998-01-13 1998-07-15 $7700.00 Window Closed / Lapsed

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