US3830401A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Toner concentration monitoring apparatus
Assignee: Eastman Kodak Co
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Filing: 1973-08-01
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Granted: 1974-08-20
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Expires: 1993-08-01
Abstract
Abstract Apparatus for continuously monitoring the concentration of toner in an electrographic developer mixture carried on a development mechanism by sensing the reflectivity of the mixture. A source of radiant energy, periodically energized at a selected frequency, is directed at the developer mixture and the reflectance thereof is monitored by a photoelectric transducer which produces a first output signal representative of the intensity of such reflectance. A second photoelectric transducer illuminated directly by the source produces a second output signal representative of the intensity of the radiation emanating from the source as modulated by the surrounding environment. The first and second output signals of the two transducers are coupled to high pass filters which eliminate signals generated by the transducers representative of ambient light and electrical noise. The a.c. output signals from the filters are converted to d.c. signals corresponding to the first and second output signals of the transducers, which d.c. signals are used to control the concentration of toner in the mixture in two alternative ways. In one embodiment, the d.c. signals are fed to a mechanism which produces a control signal proportional to the ratio of their amplitudes, which ratio is proportional to the proportion of the mixed materials. In a second embodiment, a toner replenisher is activated in response to a predetermined change in amplitude of the first d.c. signal. The second d.c. signal is used in a feedback loop for stabilizing the output of the radiation source.
Inventors
- 👤 H Siebenrock
- 👤 B Benwood
- 👤 T Morse
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:07
CPC Classifications
G; G05; G05D; G05D21/00; G05D21/02; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/0822; G03G15/0848; G03G15/0849; G03G15/0855; Y; Y10; Y10S; Y10S222/00; Y10S222/01
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
182 words
In an electrographic machine having a development mechanism which brings a developer mixture of carrier particles and toner particles having divergent reflectance characteristics into contact with a latent electrostatic image, the relative motion between the developer mixture and the latent image creating a cloud of airborne toner particles surrounding the development mechanism and an apparatus for regulating the relative proportion of the carrier and toner particles in the developer mixture, the regulating apparatus including a source of radiant energy directed toward the mixture, a first photo-electric transducer illuminated by the radiation reflected from the developer mixture, a second photoelectric transducer illuminated directly by the radiant energy source, and means responsive to the transducer outputs for producing a control signal representative of the proportion of toner and carrier particles in the mixture, the improvement wherein the second photoelectric transducer is positioned so as to receive radiation from the radiant energy source which passes through the airborne toner cloud and to provide an output signal representative of the intensity of the radiation produced by the radiant energy source as modulated by such toner cloud.
Claim 2
Dependent Claim
182 words
In an electrographic machine having a development mechanism which brings a developer mixture of carrier particles and toner particles having divergent reflectance characteristics into contact with a latent electrostatic image, the relative motion between the developer mixture and the latent image creating a cloud of airborne toner particles surrounding the development mechanism and an apparatus for regulating the relative proportion of the carrier and toner particles in the developer mixture, the regulating apparatus including a source of radiant energy directed toward the mixture, a first photo-electric transducer illuminated by the radiation reflected from the developer mixture, a second photoelectric transducer illuminated directly by the radiant energy source, and means responsive to the transducer outputs for producing a control signal representative of the proportion of toner and carrier particles in the mixture, the improvement wherein the second photoelectric transducer is positioned so as to receive radiation from the radiant energy source which passes through the airborne toner cloud and to provide an output signal representative of the intensity of the radiation produced by the radiant energy source as modulated by such toner cloud.
Claim 3
Dependent Claim
206 words
Apparatus for monitoring the proportion of a mixture of carrier and toner particles having divergent reflectance characteristics, the apparatus being used in an environment including a circulating airborne cloud of such particles, said apparatus comprising: a. a radiation source for projecting radiant energy upon a portion of the development mixture; b. means for periodically energizing said source to produce pulses of radiation at a selected frequency; c. first photosensitive means positioned to receive pulses of radiation reflected from the development mixture, said first photosensitive means being adapted to provide an output signal representative of the reflectivity of the mixture as modulated by the particle cloud; d. second photosensitive means positioned to receive pulses of radiation from said source which pass through the particle cloud, said second photosensitive means being adapted to provide an output signal representative of the intensity of the radiation produced by said source as modulated by the particle cloud; e. first and second filters coupled with the output signals from said first and second photosensitive means for filtering signals of non-selected frequencies; and f. means coupled to said first and second filters and responsive to the output signals therefrom for producing a signal representative of the proportion of toner particles in the mixture.
Claim 4
Dependent Claim
206 words
Apparatus for monitoring the proportion of a mixture of carrier and toner particles having divergent reflectance characteristics, the apparatus being used in an environment including a circulating airborne cloud of such particles, said apparatus comprising: a. a radiation source for projecting radiant energy upon a portion of the development mixture; b. means for periodically energizing said source to produce pulses of radiation at a selected frequency; c. first photosensitive means positioned to receive pulses of radiation reflected from the development mixture, said first photosensitive means being adapted to provide an output signal representative of the reflectivity of the mixture as modulated by the particle cloud; d. second photosensitive means positioned to receive pulses of radiation from said source which pass through the particle cloud, said second photosensitive means being adapted to provide an output signal representative of the intensity of the radiation produced by said source as modulated by the particle cloud; e. first and second filters coupled with the output signals from said first and second photosensitive means for filtering signals of non-selected frequencies; and f. means coupled to said first and second filters and responsive to the output signals therefrom for producing a signal representative of the proportion of toner particles in the mixture.
Claim 5
Dependent Claim
18 words
The invention as defined in claim 2 wherein said source of radiant energy comprises a light emitting diode.
Claim 6
Dependent Claim
43 words
The invention as defined in claim 2 further comprising a pair of peak detectors operatively connected to said first and secoNd photosensitive means and adapted to provide d.c. signals proportional to the peak to peak outputs of said first and second photosensitive means.
Claim 7
Dependent Claim
279 words
Apparatus for monitoring the proportion of mixed materials having divergent reflectance characteristics, said apparatus comprising: a. a container for the mixed materials; b. a luminous diode capable of emitting infrared energy when energized; c. means for periodically energizing said diode to produce pulses of infrared energy at a selected frequency; d. means for directing said pulses of infrared energy toward the mixed materials; e. a first photoelectric transducer responsive to said infrared energy positioned to receive said pulses of infrared energy after reflection by the mixed materials, said first photoelectric transducer being adapted to produce an output signal having an informational content representative of the reflectivity of the mixture as modulated by the interior environment of said container; f. a second photoelectric transducer responsive to said infrared energy positioned to receive said pulses of infrared energy directly from said diode, said second photoelectric transducer being adapted to produce an output signal having an informational content representative of the intensity of radiation emitted from said diode as modulated by the interior environment of said container; g. a pair of high pass filters coupled to the outputs of said first and second photoelectric transducers and adapted to pass signals only of said selected frequency; h. a pair of peak detectors coupled to the outputs of said first and second photoelectric transducers through said filters, said peak detectors being adapted to provide d.c. signals proportional to the peak to peak outputs from said photoelectric transducers; and i. means coupled to the outputs of said peak detectors and adapted to provide a signal proportional to the ratio of said peak detector outputs, said ratio being proportional to the proportion of the mixed materials;
Claim 8
Dependent Claim
279 words
Apparatus for monitoring the proportion of mixed materials having divergent reflectance characteristics, said apparatus comprising: a. a container for the mixed materials; b. a luminous diode capable of emitting infrared energy when energized; c. means for periodically energizing said diode to produce pulses of infrared energy at a selected frequency; d. means for directing said pulses of infrared energy toward the mixed materials; e. a first photoelectric transducer responsive to said infrared energy positioned to receive said pulses of infrared energy after reflection by the mixed materials, said first photoelectric transducer being adapted to produce an output signal having an informational content representative of the reflectivity of the mixture as modulated by the interior environment of said container; f. a second photoelectric transducer responsive to said infrared energy positioned to receive said pulses of infrared energy directly from said diode, said second photoelectric transducer being adapted to produce an output signal having an informational content representative of the intensity of radiation emitted from said diode as modulated by the interior environment of said container; g. a pair of high pass filters coupled to the outputs of said first and second photoelectric transducers and adapted to pass signals only of said selected frequency; h. a pair of peak detectors coupled to the outputs of said first and second photoelectric transducers through said filters, said peak detectors being adapted to provide d.c. signals proportional to the peak to peak outputs from said photoelectric transducers; and i. means coupled to the outputs of said peak detectors and adapted to provide a signal proportional to the ratio of said peak detector outputs, said ratio being proportional to the proportion of the mixed materials;
Claim 9
Dependent Claim
22 words
The invention as defined in claim 5 wherein said means coupled to the outputs of said peak detectors comprises a divider network.
Claim 10
Dependent Claim
260 words
Apparatus for monitoring the proportion of a development mixture of carrier and toner particles having divergent reflectance characteristics, the apparatus being used in an environment including a circulating airborne cloud of such particles, said apparatus comprising: a. a radiation source for projecting radiant energy upon a portion of the development mixture; b. means for periodically energizing said source to produce pulses of radiation at a selected frequency; c. first photosensitive means positioned to receive pulses of radiation reflected from the development mixture, said first photosensitive means being adapted to provide an output signal representative of the reflectivity of the mixture as modulated by the particle cloud; d. a first high pass filter coupled to said first photosensitive means for filtering output signals of non-selected frequencies; e. means coupled to said first high pass filter for regulating the proportion of the particles of the development mixture in response to a predetermined change in the amplitude of the output signals from said first high pass filters; f. second photosensitive means positioned to receive pulses of radiation from said source which pass through the particle cloud, said second photosensitive means being adapted to provide an output signal representative of the intensity of the radiation produced by said source as modulated by the particle cloud; and g. a second high pass filter coupled to said second photosensitive means for filtering output signals of non-selected frequencies, the output signals of said second filter being coupled to said radiation source to maintain the intensity of the radiation output produced by said source at a constant value.
Claim 11
Dependent Claim
260 words
Apparatus for monitoring the proportion of a development mixture of carrier and toner particles having divergent reflectance characteristics, the apparatus being used in an environment including a circulating airborne cloud of such particles, said apparatus comprising: a. a radiation source for projecting radiant energy upon a portion of the development mixture; b. means for periodically energizing said source to produce pulses of radiation at a selected frequency; c. first photosensitive means positioned to receive pulses of radiation reflected from the development mixture, said first photosensitive means being adapted to provide an output signal representative of the reflectivity of the mixture as modulated by the particle cloud; d. a first high pass filter coupled to said first photosensitive means for filtering output signals of non-selected frequencies; e. means coupled to said first high pass filter for regulating the proportion of the particles of the development mixture in response to a predetermined change in the amplitude of the output signals from said first high pass filters; f. second photosensitive means positioned to receive pulses of radiation from said source which pass through the particle cloud, said second photosensitive means being adapted to provide an output signal representative of the intensity of the radiation produced by said source as modulated by the particle cloud; and g. a second high pass filter coupled to said second photosensitive means for filtering output signals of non-selected frequencies, the output signals of said second filter being coupled to said radiation source to maintain the intensity of the radiation output produced by said source at a constant value.
Claim 12
Dependent Claim
38 words
The invention as defined in claim 7 further comprising first and second peak deteCtors coupled to said first and second filters, respectively, and adapted to provide d.c. signals proportional to the outputs of said first and second filters.
Claim 13
Dependent Claim
280 words
For use in an electrographic machine in which a surface carrying an electrostatic charge pattern is contacted by the bristles of an electrographic magnetic development brush, the bristles comprising an electrographic development mixture of carrier particles and toner particles having divergent reflectance characteristics, the contact of the charge pattern by the brush bristles producing an airborne toner particle cloud surrounding the development brush, an apparatus for regulating the proportion of such particles in the mixture, said apparatus comprising: a. a source of radiant energy; b. means for periodically energizing said source to produce pulses of radiation at a selected frequency; c. means for directing said pulses of radiation emanating from said source toward the development brush to irradiate a portion of the development mixture thereon; d. a first photoelectric transducer positioned to receive said pulses of radiation after reflection by the development mixture, said first photoelectric transducer being adapted to provide a first output signal representative of the reflectivity of the mixture on the development brush as modulated by the surrounding toner particle cloud; e. a second photoelectric transducer positioned to receive said pulses of radiation from said source which pass through the toner particle cloud, said second photoelectric transducer being adapted to provided a second output signal representative of the intensity of radiation emanating from said source as modulated by the surrounding toner particle cloud; f. first and second high-pass filters connected to the outputs of said first and second photoelectric transducers, respectively, for filtering signals of non-selected frequencies; and g. means responsive to said filtered first and second output signals and adapted to produce a third output signal representative of the proportion of toner particles in the mixture.
Claim 14
Dependent Claim
280 words
For use in an electrographic machine in which a surface carrying an electrostatic charge pattern is contacted by the bristles of an electrographic magnetic development brush, the bristles comprising an electrographic development mixture of carrier particles and toner particles having divergent reflectance characteristics, the contact of the charge pattern by the brush bristles producing an airborne toner particle cloud surrounding the development brush, an apparatus for regulating the proportion of such particles in the mixture, said apparatus comprising: a. a source of radiant energy; b. means for periodically energizing said source to produce pulses of radiation at a selected frequency; c. means for directing said pulses of radiation emanating from said source toward the development brush to irradiate a portion of the development mixture thereon; d. a first photoelectric transducer positioned to receive said pulses of radiation after reflection by the development mixture, said first photoelectric transducer being adapted to provide a first output signal representative of the reflectivity of the mixture on the development brush as modulated by the surrounding toner particle cloud; e. a second photoelectric transducer positioned to receive said pulses of radiation from said source which pass through the toner particle cloud, said second photoelectric transducer being adapted to provided a second output signal representative of the intensity of radiation emanating from said source as modulated by the surrounding toner particle cloud; f. first and second high-pass filters connected to the outputs of said first and second photoelectric transducers, respectively, for filtering signals of non-selected frequencies; and g. means responsive to said filtered first and second output signals and adapted to produce a third output signal representative of the proportion of toner particles in the mixture.
Claim 15
Dependent Claim
34 words
The invention as defined in claim 9 further comprising converter means coupled to said first and second filters and adapted to provide d.c. signals proportional to the outputs of said first and second filters.
Claim 16
Dependent Claim
34 words
The invention as defined in claim 9 further comprising means extending into the brush bristles for agitating the development mixture before the mixture is subjected to said pulses of radiation emanating from said source.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-08-19 | 1978-02-18 | 1978-08-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-19 | 1982-02-18 | 1982-08-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-19 | 1986-02-18 | 1986-08-20 | $7700.00 | Window Closed / Lapsed |