US3791732A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrostatic copier
Assignee: Gestetner Byfleet Ltd
•
Filing: 1972-11-15
•
Granted: 1974-02-12
•
Expires: 1992-11-15
Abstract
Abstract An electrostatic copier wherein powder images are heat set in a fuser unit and which includes a control circuit having an override device adapted to ensure completion of a fusing operation even if a main on/off switch is turned to off during such an operation. The override device can also ensure completion of a fusing operation in the event that safety devices are actuated during such an operation. This ensures completion of a fusing operation so that paper is not left in the fuser unit where it might ignite next time the copier was used. The copier additionally includes a rapid heating fuser unit and a timer motor to control copying operations.
Inventors
- 👤 J Prince
- 👤 N Mihalik
- 👤 A Moss
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:15
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/20; G03G15/2003
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
138 words
An electrostatic copier comprising in combination a fuser unit having heaters for heat fusing an image on a copy sheet in a fusing operation, electrical conductors for connecting said copier to a supply of electricity, a copier control circuit to govern operations of the copier including fusing operations and comprising a main on/off switch movable between on and off positions to connect and disconnect said circuit with said conductors, an override device connected with said main on/off switch, means to activate said override device throughout each fusing operation and means to provide a current path through said main on/off switch when in said off position on activation of said override device, whereby movement of said main on/off switch to said off position during a fusing operation does not disconnect the copier from said conductors and stop the copier.
Claim 2
Dependent Claim
138 words
An electrostatic copier comprising in combination a fuser unit having heaters for heat fusing an image on a copy sheet in a fusing operation, electrical conductors for connecting said copier to a supply of electricity, a copier control circuit to govern operations of the copier including fusing operations and comprising a main on/off switch movable between on and off positions to connect and disconnect said circuit with said conductors, an override device connected with said main on/off switch, means to activate said override device throughout each fusing operation and means to provide a current path through said main on/off switch when in said off position on activation of said override device, whereby movement of said main on/off switch to said off position during a fusing operation does not disconnect the copier from said conductors and stop the copier.
Claim 3
Dependent Claim
128 words
A copier as claimed in claim 1 and further comprising in said copier control circuit at least one safety switch in series with said main on/off switch to connect and disconnect said circuit with said conductors, said at least one safety switch being movable from a closed, normal, position to an open position on the occurrence of a copier malfunction, said override device being additionally connected with said at least one safety switch, and including means to provide a current path through said at least one safety switch when in said open position on activation of said override device, whereby movement of said at least one safety switch to its open position during a fusing operation does not disconnect the copier from said conductors and stop the copier.
Claim 4
Dependent Claim
29 words
A copier as claimed in claim 2 wherein a said at least one safety switch comprises a paper jam switch, openable on jamming of copy paper in the copier.
Claim 5
Dependent Claim
43 words
A copier as claimed in claim 2 and further comprising a tray for supporting copy paper, wherein a said at least one safety switch comprises a paper tray switch connected in series with said main switch and openable on removal of said tray.
Claim 6
Dependent Claim
50 words
A copier as claimed in claim 1 and having first and second contacts to said main switch, said first contact being connected to a said conductor, and said means to provide a current path comprising means to maintain said second contact at mains voltage on activation of said override device.
Claim 7
Dependent Claim
53 words
A copier as claimed in claim 1 and further comprising copy sheet forwarding means, an isolation relay and switches closed on actuation of said isolation relay, said switches being in series with said heaters and said forwarding means and said override device comprising means to actuate said isolation relay during a fusing operation.
Claim 8
Dependent Claim
43 words
A copier as claimed in claim 1 and further comprising a fuser timer motor, switches closable on operation of said motor to supply current to said heaters during a fusing operation, and means to activate said override device on operation of said motor.
Claim 9
Dependent Claim
42 words
A copier as claimed in claim 1 and further comprising a cover and a cover switch openable responsive to opening of said cover and which is in series with said main on/off switch to connect and disconnect said circuit with said conductors.
Claim 10
Dependent Claim
62 words
A copier as claimed in claim 1 and further comprising a copy switch, a control relay, means to activate said control relay after closure of said copy switch, further components of said copier, said further components comprising a drive motor, illumination means anD a high tension supply and switches closed on activation of said relay to supply current to said further components.
Claim 11
Dependent Claim
37 words
A copier as claimed in claim 9 and further comprising a delay circuit, a delayed relay and a timer motor, actuation of said copy switch energising said delayed relay after a delay to activate said timer motor.
Claim 12
Dependent Claim
72 words
A copier as claimed in claim 10 and further comprising copy sheet forwarding means, an isolation relay and switches closed on actuation of said isolation relay, said switches being in series with said heaters and said forwarding means, and said override device comprising means to actuate said isolation relay during a fusing operation, andd said delayed relay being connected to switch said isolation relay into a latching circuit with said main switch.
Claim 13
Dependent Claim
82 words
A copier as claimed in claim 10 and further comprising at least one copy circuit safety switch device movable from a closed, normal position to an open position on the occurrence of a copier malfunction and means to prevent operation of said control relay on actuation of said copy switch when a said copy circuit safety switch is open, and further comprising current supply means to said timer motor which is in parallel with said at least one copy circuit safety switch.
Claim 14
Dependent Claim
58 words
A copier as claimed in claim 9 and further comprising at least one copy circuit safety switch movable from a closed, normal position to an open position on the occurrence of a copier malfunction, and means to prevent operation of said control relay on actuation of said copy switch, when a said copy circuit safety switch is open.
Claim 15
Dependent Claim
36 words
A copier as claimed in claim 13 wherein said at least one copy circuit safety switch is opened in response to at least one of a cleaning tissue shortage, a copy paper shortage and machine overheat.
Claim 16
Dependent Claim
67 words
A copier as claimed in claim 1 and further comprising a fuser unit, a fuser thermostat and heaters to said fuser unit, means to operate said heater continuously when a copying operation commences with said thermostat closed, a relay operable on opening of said thermostat, an electronic gating device connected to said heaters when said relay operates, and means connecting said thermostat to control said gating device.
Claim 17
Dependent Claim
46 words
A copier as claimed in claim 15 and further comprising a fuser timer motor, said motor, in use, activating said override device, and a further switch closable by said timer motor to close said gating device while a copy sheet is passed through said fuser unit.
Claim 18
Dependent Claim
17 words
A copier as claimed in claim 16 and further comprising further heaters connected to said further switch.
Claim 19
Dependent Claim
17 words
A copier as claimed in claim 15 and further comprising further heaters connected to said fuser thermostat.
References Cited (Backward Citations)
US3512885A
Cited
US3661452A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-11 | 1977-08-13 | 1978-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-11 | 1981-08-13 | 1982-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-11 | 1985-08-13 | 1986-02-12 | $7700.00 | Window Closed / Lapsed |