US3739800A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Toner supply system for copying machine
Assignee: COPYSTATICS Inc C/O LOWENTHAL A DE CORP
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Filing: 1971-05-04
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Granted: 1973-06-19
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Expires: 1991-05-04
Abstract
Abstract A system for continuously monitoring the concentration of toner in an electrostatic copying machine. The need for additional toner concentrate is detected by a photocell which receives varying amounts of light transmitted through a transparent monitoring tube positioned in the toner solution circulation path. If the toner solution has become too dilute, the photocell''s resistance lowers to permit a periodically generated enabling pulse from the electronic control circuit to furnish an operating path for a positive-acting solenoid valve. Short timed bursts of toner concentrate are then added to the toner solution at spaced time intervals unitl the concentration exceeds a predetermined value; the concentrate is injected into the solution by an immersed venturi tube arrangement. A manual operating mode is also included for providing an instantaneous burst of toner concentrate independent of the detection circuitry.
Inventors
- 👤 T Aasen
- 👤 B Mogil
- 👤 M Schaffel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:23
CPC Classifications
G; G05; G05D; G05D21/00; G05D21/02; G03; G03G; G03G15/00; G03G15/06; G03G15/10; G03G15/104; G03G15/105; Y; Y10; Y10T; Y10T137/00; Y10T137/2496; Y10T137/2499; Y10T137/2509
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
207 words
A toner replenishing system adapted for use in an electrostatic copying machine comprising a supply of developer solution, a supply of toner, means for monitoring the optical density of said developer solution, valve means for controlling the addition of toner from said toner supply to said supply of developer solution, a switching device connected to said valve means, said switching device having a gate electrode, a timing circuit for providing a periodic timing pulse, a triggering circuit connected to said timing circuit for supplying a periodic voltage spike to the gate electrode of said switching device in response to said periodic timing pulse, said periodic voltage spike being of insufficient voltage level required to trigger said switching device into conduction, a voltage divider for supplying a base voltage to the gate electrode of said switching device, said voltage divider including said monitoring means such that a change in the optical density of said developer solution below a preselected level will increase said base voltage to a sufficient level such that said base voltage in combination with said periodic voltage spike is sufficient to trigger said switching device into conduction and thereby enable said timing circuit to energize said valve means to add toner to said developer solution.
Claim 2
Dependent Claim
207 words
A toner replenishing system adapted for use in an electrostatic copying machine comprising a supply of developer solution, a supply of toner, means for monitoring the optical density of said developer solution, valve means for controlling the addition of toner from said toner supply to said supply of developer solution, a switching device connected to said valve means, said switching device having a gate electrode, a timing circuit for providing a periodic timing pulse, a triggering circuit connected to said timing circuit for supplying a periodic voltage spike to the gate electrode of said switching device in response to said periodic timing pulse, said periodic voltage spike being of insufficient voltage level required to trigger said switching device into conduction, a voltage divider for supplying a base voltage to the gate electrode of said switching device, said voltage divider including said monitoring means such that a change in the optical density of said developer solution below a preselected level will increase said base voltage to a sufficient level such that said base voltage in combination with said periodic voltage spike is sufficient to trigger said switching device into conduction and thereby enable said timing circuit to energize said valve means to add toner to said developer solution.
Claim 3
Dependent Claim
37 words
A toner replenishing system according to claim 1 wherein said monitoring means includes a light source, a photosensitive element, and means mounting said light source and said photosensitive element in a spaced relation with developer solution therebetween.
Claim 4
Dependent Claim
42 words
A toner replenishing system according to claim 2 wherein the electrical resistance of said photosensitive element of said monitoring means decreases in response to a decrease in the optical density of said developer solution sufficient to trigger said switching device into conduction.
Claim 5
Dependent Claim
53 words
A toner replenishing system according to claim 1 wherein said valve means for controlling the addition of toner includes a feed path from said toner supply to said supply of developer solution having a solenoid valve positioned therein for normally blocking said feed path and operative to open said feed path upon energization.
Claim 6
Dependent Claim
36 words
A toner replenishing system according to claim 1 wherein said monitoring means includes a light source, a photocell, and a transparent monitoring tube having developer solution flowing therethrough disposed between said light source and said photocell.
Claim 7
Dependent Claim
15 words
A toner replenishing system according to claim 1 wherein said switching device includes an SCR.
Claim 8
Dependent Claim
17 words
A toner replenishing system according to claim 1 wherein said triggering circuit includes a resistor-capacitor pulse-forming network.
Claim 9
Dependent Claim
17 words
A toner replenishing system according to claim 1 wherein said timing circuit includes a free-running multivibrator circuit.
Claim 10
Dependent Claim
26 words
A toner replenishing system according to Claim 1 including means for effecting actuation of said switching device independent of the optical density of said developer solution.
Claim 11
Dependent Claim
46 words
A toner replenishing system according to claim 9 wherein said means for effecting independent actuation of said switching device includes switch means for applying a sufficient voltage directly to said switching device thereby actuating said device and enabling said timing circuit to energize said valve means.
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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) | 1976-06-18 | 1976-12-18 | 1977-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-18 | 1980-12-18 | 1981-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-18 | 1984-12-18 | 1985-06-19 | $7700.00 | Window Closed / Lapsed |