US3709604A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Roll end detector
Assignee: Individual
•
Filing: 1970-07-20
•
Granted: 1973-01-09
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Expires: 1990-07-20
Abstract
Abstract In order to determine when a roll of web material, such as paper, wound on a core has reached its end, a photoelectric detecting circuit is provided. The photoelectric apparatus is shown in combination with an electrostatic copying machine and includes a pair of photocells in a bridge circuit. One photocell receives light directly from a source while the other receives light reflected from the surface of a roll of web material. When the web material has been unwound to expose a core of a different color, the intensity of the reflected light changes causing the bridge circuit to become unbalanced, which unbalance is amplified and utilized to operate control means.
Inventors
- 👤 G Niesen
- 👤 M Yoon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 01:09
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/65; G03G15/6517; G03G15/6523; G03B; G03B21/00; G03B21/14; G03B21/32; G03B21/43; G03G15/6588; G03G15/6594; G03G15/6597; G03G2215/00; G03G2215/00362; G03G2215/00443; G03G2215/00518
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
165 words
In a copying machine having means for supplying light sensitive copying paper from a roll of such paper; means for severing such paper unwound from the roll into desired lengths; means for exposing a severed length of such paper to an original to create a latent image of the original on the copying paper; and means for developing said latent image to cause it to become visible; the improvement comprising a light source; lightsensitive means exposed to said light source and to light substantially in the invisible portion of the light spectrum reflected from said source by the copying paper; means for supplying electriCal energy to said light-sensitive means; circuit means responsive to current flow in said light-sensitive means to produce a control signal when current flow through said light-sensitive means changes in response to a variation in light reflected from the copying paper; and circuit control means responsive to the control signal to actuate a circuit control element when the control signal is produced.
Claim 2
Dependent Claim
165 words
In a copying machine having means for supplying light sensitive copying paper from a roll of such paper; means for severing such paper unwound from the roll into desired lengths; means for exposing a severed length of such paper to an original to create a latent image of the original on the copying paper; and means for developing said latent image to cause it to become visible; the improvement comprising a light source; lightsensitive means exposed to said light source and to light substantially in the invisible portion of the light spectrum reflected from said source by the copying paper; means for supplying electriCal energy to said light-sensitive means; circuit means responsive to current flow in said light-sensitive means to produce a control signal when current flow through said light-sensitive means changes in response to a variation in light reflected from the copying paper; and circuit control means responsive to the control signal to actuate a circuit control element when the control signal is produced.
Claim 3
Dependent Claim
79 words
The improvement of claim 1 wherein said light-sensitive means comprises a pair of photocells, means mounting one of said photocells so as to expose it to the light from said source; means mounting the other of said photocells so as to expose it to light reflected from the paper; and wherein means for supplying electrical energy includes a bridge circuit comprising a potentiometer and one of said photocells is connected in each of the arms of said bridge circuit.
Claim 4
Dependent Claim
29 words
The improvement of claim 2 including filter means passing only invisible portions of the light spectrum interposed between said other of said photocells and the roll of copying paper.
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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) | 1976-01-09 | 1976-07-10 | 1977-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-09 | 1980-07-10 | 1981-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-09 | 1984-07-10 | 1985-01-09 | $7700.00 | Window Closed / Lapsed |