US3928764A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for measuring and controlling the toner concentration in electrophotographic reproduction machines
Assignee: Hoechst AG
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Filing: 1973-06-04
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Granted: 1975-12-23
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Expires: 1993-06-04
Abstract
Abstract A method of measuring the toner concentration of a developer containing toner circulating in an electrophotographic reproduction machine including preparing a sample from the developer for measurement, arranging the sample so that the toner can be estimated as a proportion of the required toner concentration of the developer, irradiating the sample by Beta rays that are effected by the toner and measuring the Beta -rays being scattered back from the irradiation. An apparatus for measuring the toner concentration of a developer including an endless belt mounted for movement with part of its surface horizontal for forming a uniform layer of developer thereon for measurement, a measuring head as a source of Beta -rays positioned to irradiate the uniform layer of developer, a detector for measuring the effect of the irradiation, an electronic unit responsive to the measured radiation and a toner supply device operable by the electronic unit to replenish toner in the developer when needed. In lieu of the endless belt the photoconductive surface of the electrophotographic reproduction machine may be provided with one or more electrodes to which an electrical potential may be applied.
Inventors
- 👤 Hartmut Bock
- 👤 Hans Gotte
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:20
CPC Classifications
G; G01; G01N; G01N23/00; G01N23/02; G01N23/06; G01N23/12; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/0822; G03G15/0848; G03G15/0849; G03G15/0855; G03G15/0887; G03G15/0889
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
73 words
A method of measuring the toner concentration of a developer containing toner circulating in an electrophotographic reproduction machine, comprising forming a horizontal layer of developer of constant thickness from the circulating developer for measurement, passing said layer past a source of Beta -rays that are effected by the toner, irradiating the layer by Beta rays and measuring the Beta -rays being scattered back from said irradiation to determine the amount of toner present.
Claim 2
Independent Claim
73 words
A method of measuring the toner concentration of a developer containing toner circulating in an electrophotographic reproduction machine, comprising forming a horizontal layer of developer of constant thickness from the circulating developer for measurement, passing said layer past a source of Beta -rays that are effected by the toner, irradiating the layer by Beta rays and measuring the Beta -rays being scattered back from said irradiation to determine the amount of toner present.
Claim 3
Dependent Claim
44 words
The method as claimed in claim 1, in which the sample constituted by the developer itself is at a constant distance at its closest point from the radiation source and measuring device, whereby irradiation and back-scatter are from the same side of the sample.
Claim 4
Dependent Claim
17 words
The method as claimed in claim 1, in which the radiation source is a C 14 preparation.
Claim 5
Dependent Claim
25 words
The method as claimed in claim 1, in which the radiation source is a Sr 90/Y 90, a Pm 147 or a Tl 204 preparation.
Claim 6
Independent Claim
105 words
An apparatus for measuring the toner concentration of a developer containing toner circulating in an electrophotographic reproduction machine including means for preparing and arranging a sample from the developer for irradiation comprising an endless belt mounted for circulation with part of its outer surface horizontal and facing upwards and means for forming a layer of developer of constant thickness on this part of the belt, a measuring head as a source of Beta -rays located for irradiation of the sample being located to irradiate developer on this part of the belt and a detector for measuring the effect of the sample on the said radiation.
Claim 7
Independent Claim
105 words
An apparatus for measuring the toner concentration of a developer containing toner circulating in an electrophotographic reproduction machine including means for preparing and arranging a sample from the developer for irradiation comprising an endless belt mounted for circulation with part of its outer surface horizontal and facing upwards and means for forming a layer of developer of constant thickness on this part of the belt, a measuring head as a source of Beta -rays located for irradiation of the sample being located to irradiate developer on this part of the belt and a detector for measuring the effect of the sample on the said radiation.
Claim 8
Dependent Claim
45 words
The apparatus as claimed in claim 5, further including electronic means arranged to be responsive to the received radiation and a toner supply device operable by said electronic means to replenish the toner in the developer in accordance with the amount of the resulting radiation.
Claim 9
Dependent Claim
42 words
The apparatus as claimed in claim 5, in which the means for forming the layer of developer comprises a collector-hopper for delivering developer to the belt, a layer thickness determining means, and lateral confining walls at least in the zone of irradiation.
Claim 10
Dependent Claim
30 words
The apparatus as claimed in claim 5, in which the means for preparing and arranging the sample for measurement include the charging device and developing device of the electrophotographic machine.
Claim 11
Dependent Claim
53 words
The apparatus as claimed in claim 5, in which as radiation source a Beta -ray source is located to face the free surface of the layer of developer and the detector is a detector for detecting Beta -rays back-scattered by the developer, the detector being screened from direct radiation from the said source.
Claim 12
Dependent Claim
44 words
The apparatus as claimed in claim 9, in which the detector is of circular section and the Beta -ray source is a counting tube positioned in the center of this circle between the detector and the developer, said detector being screened from said source.
Claim 13
Dependent Claim
26 words
The apparatus as claimed in claim 9, in which the detector is a counting tube and the radiation source is located on a ring around it.
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) | 1978-12-22 | 1979-06-23 | 1979-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-22 | 1983-06-23 | 1983-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-22 | 1987-06-23 | 1987-12-23 | $7700.00 | Window Closed / Lapsed |