US4486090A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Copy machine with unauthorized copy prevention
Assignee: 3M Co
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Filing: 1983-03-21
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Granted: 1984-12-04
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Expires: 2003-03-21
Abstract
Abstract A copy machine having an eddy current proximity detector positioned so relative movement is provided between the detector and a document to be copied. The detector is connected to control logic circuitry for the copy machine so that the copy machine is prevented from producing a copy when the detector detects metal carried by the document. A document cover position indicating device is also connected to the control logic for the copy machine so that closure of the document cover is required for the production of a copy.
Inventors
- 👤 Nicholas Warhol
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 23:14
CPC Classifications
G; G03; G03G; G03G21/00; G03G21/04; G03G21/046
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
271 words
A copy machine of the type having a document cover than can be positioned over a document presented to a platen in the copy machine for copying and having control logic circuitry for controlling the copying process of the copy machine which uses a charge corona control for operation of a charge corona to supply a uniform charge to a photoconductor and a transfer corona control for operation of a transfer corona including: an eddy current proximity detector having an output connected to the control logic circuitry and positioned so relative movement is provided between said eddy current proximity detector and a document to be copied when the copy machine is operated, said detector adapted for providing a signal at said output whenever metal is presented to the detector via a document presented for copying; latching means operatively connected to said output of said detector and to the control logic circuitry, said latching means providing a latch condition when the control logic circuitry provides an enable signal to said latching means at the time said output is provided, the control logic circuitry providing an enable signal to said latching means when relative movement is provided between said eddy current proximity detector and a document to be copied such that said eddy current proximity detector will provide a signal to said output due to metal present at the document to be copied; and the control logic circuitry operatively connected to the charge corona control, transfer corona control and to said latching means, said control logic circuitry inhibiting the operation of the charge corona control when said latching means provides a latch condition.
Claim 2
Dependent Claim
271 words
A copy machine of the type having a document cover than can be positioned over a document presented to a platen in the copy machine for copying and having control logic circuitry for controlling the copying process of the copy machine which uses a charge corona control for operation of a charge corona to supply a uniform charge to a photoconductor and a transfer corona control for operation of a transfer corona including: an eddy current proximity detector having an output connected to the control logic circuitry and positioned so relative movement is provided between said eddy current proximity detector and a document to be copied when the copy machine is operated, said detector adapted for providing a signal at said output whenever metal is presented to the detector via a document presented for copying; latching means operatively connected to said output of said detector and to the control logic circuitry, said latching means providing a latch condition when the control logic circuitry provides an enable signal to said latching means at the time said output is provided, the control logic circuitry providing an enable signal to said latching means when relative movement is provided between said eddy current proximity detector and a document to be copied such that said eddy current proximity detector will provide a signal to said output due to metal present at the document to be copied; and the control logic circuitry operatively connected to the charge corona control, transfer corona control and to said latching means, said control logic circuitry inhibiting the operation of the charge corona control when said latching means provides a latch condition.
Claim 3
Dependent Claim
96 words
A copy machine according to claim 1 further including: a document cover position detector operatively associated with the document and operatively connected to said control logic circuit for providing an electrical indication of the open-closed status of the document cover, the control logic circuitry requiring said electrical indication to reflect a closed status for the document cover before a copy process cycle can begin and inhibiting the operation of the charge corona control and transfer corona control when a document cover open status is provided by said electrical indication after a copy process cycle has begun.
Claim 4
Dependent Claim
37 words
A copy machine according to claim 1 wherein the relative movement provided between said eddy current proximity detector and a document to be copied is provided after the document to be copied is positioned on the platen.
Claim 5
Dependent Claim
43 words
A copy machine according to claim 1 wherein said latching means includes a drive circuit operatively connected to said output of said eddy current proximity detector and a latching relay operatively connected to said drive circuit, said latching relay providing said latch condition.
Claim 6
Dependent Claim
32 words
A copy machine according to claim 4 wherein said latching relay includes an input for manually initiating the resetting of said latching relay when said latching relay is presenting a latch condition.
Claim 7
Dependent Claim
42 words
A copy machine according to claim 1 wherein the relative movement provided between said eddy current proximity detector and a document to be copied is provided by movement of said eddy current proximity detector with the document in position at the platen.
Claim 8
Dependent Claim
75 words
A copy machine according to claim 6 wherein the copy machine further includes metal positioned for detection by said eddy current proximity detector during a portion of the movement of said eddy current proximity detector for providing said control logic circuitry with a signal at said output of said eddy current proximity detector when said metal included in the copy machine is detected which is usable to verify operability of said eddy current proximity detector.
Claim 9
Dependent Claim
84 words
A copy machine according to claim 7 further including a pulse generator operatively connected for supplying a series of pulses to the control logic circuitry and a position indicator operatively connected to the control logic circuitry and positioned for actuation at a point in the movement of said eddy current proximity detector, said actuation usable by the control logic circuit for providing a starting point for utilization of said series of pulses for determining when said enable signal is provided to said latching means.
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) | 1987-12-04 | 1988-06-04 | 1988-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-12-04 | 1992-06-04 | 1992-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-12-04 | 1996-06-04 | 1996-12-04 | $7700.00 | Window Closed / Lapsed |