US3699992A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrophotographic apparatus
Assignee: Canon Inc
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Filing: 1970-07-13
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Granted: 1972-10-24
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Expires: 1990-07-13
Abstract
Abstract A photocopying apparatus which comprises supply means for supplying a predetermined quantity of concentrated developing agent to carrier liquid at a predetermined time interval, and measuring means for continuously measuring the concentration of the developing liquid. The measuring means controls said supply means so that the supply means supplies such measured quantity of concentrated developing agent to the carrier liquid only during predetermined time intervals and then only where the developing liquid has lower than a predetermined value of concentration. The carrier liquid is independently supplied in a quantity equal to the consumption of the carrier liquid, whereby constant concentration of the developing solution is maintained.
Inventors
- 👤 Wilhelm Josef Knechtel
- 👤 Detlef Schaffer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 08:06
CPC Classifications
G; G03; G03D; G03D3/00; G03D3/02; G03D3/06; G03G; G03G15/00; G03G15/06; G03G15/10; G03G15/104; G03G15/105; Y; Y10; Y10T; Y10T137/00; Y10T137/0318; Y10T137/0324; Y10T137/0329; Y10T137/034; Y10T137/2496; Y10T137/2499; Y10T137/2509
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
141 words
Apparatus for use in developing electrostatic images comprising: a. a tank containing developing solution comprising carrier liquid admixed with developing agent; b. means circulating said developing solution; c. sensing means generating first output signals during operation of said circulating means, said first outpuT signals being indicative of the concentration of developing agent in said developing solution; d. means generating time-spaced signals during operation of said circulating means; e. means receiving said first output signals and said timespaced signals and operatively responsive thereto to generate second output signals exclusively upon the concurrent occurrence of said time-spaced signals and first output signals indicative of developing agent concentration of magnitude less than a preselected magnitude; and f. developing agent supply means operatively responsive to said second output signals to supply developing agent to said tank during the time extents of said second output signals.
Claim 2
Dependent Claim
141 words
Apparatus for use in developing electrostatic images comprising: a. a tank containing developing solution comprising carrier liquid admixed with developing agent; b. means circulating said developing solution; c. sensing means generating first output signals during operation of said circulating means, said first outpuT signals being indicative of the concentration of developing agent in said developing solution; d. means generating time-spaced signals during operation of said circulating means; e. means receiving said first output signals and said timespaced signals and operatively responsive thereto to generate second output signals exclusively upon the concurrent occurrence of said time-spaced signals and first output signals indicative of developing agent concentration of magnitude less than a preselected magnitude; and f. developing agent supply means operatively responsive to said second output signals to supply developing agent to said tank during the time extents of said second output signals.
Claim 3
Dependent Claim
43 words
The apparatus claimed in claim 1 wherein said developing agent supply means comprises a container containing concentrated developing agent, conduit means connecting said container and said tank and a pump disposed in said conduit means and operatively responsive to said second output signals.
Claim 4
Dependent Claim
26 words
The apparatus claimed in claim 2 wherein said second output signal generating means includes a coincidence circuit receiving said first output signals and said time-spaced signals.
Claim 5
Dependent Claim
180 words
Apparatus for use in developing electrostatic images comprising: a. a tank containing developing solution comprising carrier liquid admixed with developing agent; b. means circulating said developing solution; c. sensing means generating first output signals during operation of said circulating means, said first output signals being indicative of the concentration of developing agent in said developing solution; d. means generating second output signals at predetermined periods during operation of said circulating means exclusively upon the occurrence during said periods of first output signals indicative of developing agent concentration of magnitude less than a preselected magnitude, sad second output signal generating means comprising first circuit means generating pulses time-spaced from one another and each of time extent defining a one of said predetermined periods and second circuit means including a coincidence circuit operatively responsive to said pulses and said first output signals, said coincidence circuit providing output signals constituting said second output signals; and e. developing agent supply means operatively responsive to said second output signals to supply developing agent to said tank during the time extents of said second output signals.
Claim 6
Dependent Claim
180 words
Apparatus for use in developing electrostatic images comprising: a. a tank containing developing solution comprising carrier liquid admixed with developing agent; b. means circulating said developing solution; c. sensing means generating first output signals during operation of said circulating means, said first output signals being indicative of the concentration of developing agent in said developing solution; d. means generating second output signals at predetermined periods during operation of said circulating means exclusively upon the occurrence during said periods of first output signals indicative of developing agent concentration of magnitude less than a preselected magnitude, sad second output signal generating means comprising first circuit means generating pulses time-spaced from one another and each of time extent defining a one of said predetermined periods and second circuit means including a coincidence circuit operatively responsive to said pulses and said first output signals, said coincidence circuit providing output signals constituting said second output signals; and e. developing agent supply means operatively responsive to said second output signals to supply developing agent to said tank during the time extents of said second output signals.
Claim 7
Dependent Claim
20 words
The apparatus claimed in claim 3 including a voltage-sensitive bistable circuit connected between said sensing means and said coincidence circuit.
Claim 8
Dependent Claim
33 words
The apparatus claimed in claim 5 wherein said coincidence circuit comprises an AND gate receiving a first input from said bistable circuit and a second input from said means generating said time-spaced signals.
Claim 9
Dependent Claim
26 words
The apparatus claimed in claim 6 further including an operational amplifier receiving said AND gate output signal, said amplifier output signals constituting said second output signals.
Claim 10
Dependent Claim
32 words
The apparatus claimed in claim 1 wherein said circulating means includes a conduit and wherein said sensing means includes a light source and a photocell disposed in opposing relation in said conduit.
Claim 11
Dependent Claim
15 words
The apparatus claimed in claim 1 further including a rotating stirrer disposed in said tank.
Claim 12
Dependent Claim
20 words
The apparatus claimed in claim 8 wherein said circulating means further includes a pump connecting said tank and said conduit.
Claim 13
Dependent Claim
26 words
The apparatus claimed in claim 8 wherein said conduit comprises a transparent section, said light source and said photocell being mounted on said transparent conduit section.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-24 | 1976-04-24 | 1976-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-24 | 1980-04-24 | 1980-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-24 | 1984-04-24 | 1984-10-24 | $7700.00 | Window Closed / Lapsed |