US3872824A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Xerographic toner concentration control apparatus
Assignee: Van Dyk Research Corp
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Filing: 1973-07-20
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Granted: 1975-03-25
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Expires: 1993-07-20
Abstract
Abstract An arrangement for measuring the concentration of toner powder in a xerographic developer mixture by causing a sample of the developer to impinge upon a transparent plate. By providing the developer sample in the form of a turbulent stream, inclining the plate at the proper angle, and arranging the geometry of the measuring apparatus so that the stream impinges upon the transparent plate with the proper kinetic energy, a layer of toner powder is formed on the surface of a portion of the plate, the thickness of the toner layer increasing and decreasing with corresponding changes in the concentration of toner in the developer mixture. A photoelectric system is employed to monitor the light transmission of the toner-coated plate to provide a measure of toner concentration.
Inventors
- 👤 Daniel Richard Erny
- 👤 Leon Albert Tysko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:32
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/0822; G03G15/0848; G03G15/0849; G03G15/0855
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
293 words
Apparatus for controlling the toner concentration of the developer in the developer tank of a xerographic copying apparatus, comprising: a developer sample storage hopper; a supply conduit for transporting a portion of the developer in said tank to said hopper; a lower orifice in said hopper for permitting developer stored in said hopper to flow through said orifice in a stream at a rate limited by the size of the orifice; first and second inclined light transmissive toner collecting plates; a developer stream deflecting element situated below said orifice for (i) introducing a substantial amount of turbulence into said stream by disrupting the flow of developer in said stream, for (ii) dividing the stream into at least two relatively turbulent streamlets, and for (iii) directing said turbulent streamlets onto respective ones of said collecting plates with kinetic energy sufficient to dislodge toner particles from the developer carrier beads to which the particles are electroscopically adherent, said dislodged toner particles being deposited upon said collecting plate portions, the kinetic energy and turbulence of said developer streamlets being sufficient to remove toner particles from said collecting plate portions when the concentration of toner in said streamlets decreases, said kinetic energy being sufficiently low so that the developer is not damaged by impact with said collecting plates; at least one light source for illuminating said collecting plate portions; a photosensitive element for generating a control signal responsive to the light from said source which is transmitted through said collecting plate portions; means coupled to said element for varying the concentration of toner in the developer within said tank in accordance with said control signal; and conduit means for returning the developer in said streamlets to said tank after the streamlets have impinged on said collecting plates.
Claim 2
Dependent Claim
293 words
Apparatus for controlling the toner concentration of the developer in the developer tank of a xerographic copying apparatus, comprising: a developer sample storage hopper; a supply conduit for transporting a portion of the developer in said tank to said hopper; a lower orifice in said hopper for permitting developer stored in said hopper to flow through said orifice in a stream at a rate limited by the size of the orifice; first and second inclined light transmissive toner collecting plates; a developer stream deflecting element situated below said orifice for (i) introducing a substantial amount of turbulence into said stream by disrupting the flow of developer in said stream, for (ii) dividing the stream into at least two relatively turbulent streamlets, and for (iii) directing said turbulent streamlets onto respective ones of said collecting plates with kinetic energy sufficient to dislodge toner particles from the developer carrier beads to which the particles are electroscopically adherent, said dislodged toner particles being deposited upon said collecting plate portions, the kinetic energy and turbulence of said developer streamlets being sufficient to remove toner particles from said collecting plate portions when the concentration of toner in said streamlets decreases, said kinetic energy being sufficiently low so that the developer is not damaged by impact with said collecting plates; at least one light source for illuminating said collecting plate portions; a photosensitive element for generating a control signal responsive to the light from said source which is transmitted through said collecting plate portions; means coupled to said element for varying the concentration of toner in the developer within said tank in accordance with said control signal; and conduit means for returning the developer in said streamlets to said tank after the streamlets have impinged on said collecting plates.
Claim 3
Dependent Claim
76 words
Apparatus according to claim 1, further including a bypass conduit for returning a portion of any developer in said sample storage hopper to said developer tank without permitting said developer portion to impinge on said collecting plates, said developer portion being returned at a sufficient rate to insure that the concentration of toner in the developer within said hopper is at all times substantially equal to the concentration of toner in the developer within said tank.
Claim 4
Dependent Claim
18 words
Apparatus according to claim 2, wherein said light source and said photosensitive element are situated in dust-free compartments.
Claim 5
Dependent Claim
33 words
Apparatus according to claim 2, wherein the carrier beads of said developer comprise steel pellets having a coating thereon of a material removed from the material of said toner in the triboelectric series.
Claim 6
Dependent Claim
17 words
Apparatus according to claim 2, wherein said deflecting element is in the form of an inverted V.
Claim 7
Dependent Claim
12 words
Apparatus according to claim 5, wherein said deflecting element is electrically conductive.
Claim 8
Dependent Claim
11 words
Apparatus according to claim 6, wherein said deflecting element is grounded.
Claim 9
Dependent Claim
13 words
Apparatus according to claim 6, wherein said deflecting element comprises steel or aluminum.
Claim 10
Dependent Claim
23 words
Apparatus according to claim 5, wherein the angle formed by the V of the deflecting element is on the order of 60 degrees.
Claim 11
Dependent Claim
35 words
Apparatus according to claim 2, wherein said collecting plates are disposed below said deflecting element and the normals to said plaTes are inclined at an angle of 30 to 75* with respect to the vertical.
Claim 12
Dependent Claim
14 words
Apparatus according to claim 10, wherein said angles are on the order of 60*.
Claim 13
Dependent Claim
31 words
Apparatus according to claim 10, wherein the vertical distance between said orifice and the adjacent portion of said deflecting element directly beneath said orifice is on the order of three-sixteenth inch.
Claim 14
Dependent Claim
32 words
Apparatus according to claim 12, wherein the vertical distances between said collecting plate portions and the parts of said deflecting element above said plate portions are on the order of 0.25 inch.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |