EP0177977A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Bottom margin indicator apparatus for typewriters
Assignee: Individual
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Filing: 1982-07-06
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Granted: —
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Expires: 2002-07-06
Abstract
Abstract Bottom-edge margin indicators for typewriter paper and the like using an optical sensor-monitor wherein spurious effects of the edge of the paper exiting from the bottom margin sensor region and pre-printed material thereon are obviated, and in which the sensor-monitor of the bottom edge of the paper is preferably carried by the platen shield (2) itself in a manner that is particularly advantageous for optical sensing of the paper, with the sensor (7-7') maintained in extremely close proximity to the paper irrespective of its thich- ness, and adapted for simple and ready adjustment, if desired, to vary the margin setting.
Inventors
- 👤 Carol M. Rines
- 👤 Duane Marshall
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 03:40
CPC Classifications
B; B41; B41J; B41J29/00; B41J29/46; B41J29/48
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
162 words
Bottom margin indicator apparatus for typewriter paper and the like operating with typewriters having a platen rotatable about its axis and around the cylindrical surface of which the paper is advanced in a transverse path during typewriting, said apparatus having, in combination, cylindrical-section paper shield means mountable below the platen and between the upper surface of which and the platen the paper is thus advanced; monitor means mounted in close proximity to said path in proximity to, the paper passed between the same and the platen irrespective _ of thickness of the paper; signaling means connected to and responsive to the sensing by the monitor means of the absence of paper following the presence of paper thereat for providing an indication of the advent of such absence; and means for preventing spurious signals from being applied by said signaling means that would effect spurious and multiple indications as the bottom edge of the paper or pre-printed material passes by the monitor means.
Claim 2
Dependent Claim
162 words
Bottom margin indicator apparatus for typewriter paper and the like operating with typewriters having a platen rotatable about its axis and around the cylindrical surface of which the paper is advanced in a transverse path during typewriting, said apparatus having, in combination, cylindrical-section paper shield means mountable below the platen and between the upper surface of which and the platen the paper is thus advanced; monitor means mounted in close proximity to said path in proximity to, the paper passed between the same and the platen irrespective _ of thickness of the paper; signaling means connected to and responsive to the sensing by the monitor means of the absence of paper following the presence of paper thereat for providing an indication of the advent of such absence; and means for preventing spurious signals from being applied by said signaling means that would effect spurious and multiple indications as the bottom edge of the paper or pre-printed material passes by the monitor means.
Claim 3
Dependent Claim
48 words
Bottom margin indicator apparatus as claimed in claim-1 and in which said spurious signal preventing means comprises means responsive to the hysterisis effect resulting between signals produced upon paper entering and exiting from the region of said monitor means for generating an unambiguous indicator signal following such exiting.
Claim 4
Dependent Claim
45 words
Bottom margin indicator apparatus as claimed in claim 2 and in which said hysterisis effect responsive means comprises a Schmidt circuit responsive to the output of said monitor means coupled to a one-shot circuit for generating said indicator signal as a pulse of predetermined duration.
Claim 5
Dependent Claim
109 words
Bottom margin indicator apparatus for typewriter paper and the like in which the paper is advanced in a predetermined path, monitor means mounted in close proximity to said path in non-intefering relationship with, but in close proximity to, the paper; signaling means connected to and responsive to the sensing by the monitor means of the absence of paper following the presence of paper thereat, for providing an indication of the advent of such absence; and means for preventing spurious signals from being applied by said signaling means that would effect spurious and multiple indications as the bottom edge of the paper or pre-printed material passes by the monitor means.
Claim 6
Dependent Claim
109 words
Bottom margin indicator apparatus for typewriter paper and the like in which the paper is advanced in a predetermined path, monitor means mounted in close proximity to said path in non-intefering relationship with, but in close proximity to, the paper; signaling means connected to and responsive to the sensing by the monitor means of the absence of paper following the presence of paper thereat, for providing an indication of the advent of such absence; and means for preventing spurious signals from being applied by said signaling means that would effect spurious and multiple indications as the bottom edge of the paper or pre-printed material passes by the monitor means.
Claim 7
Dependent Claim
25 words
Bottom margin indicator apparatus as claimed in claim 4 and in which said monitor means comprises photo sensing means responsive to illumination of the paper.
Claim 8
Dependent Claim
49 words
Bottom margin indicator apparatus as claimed in claim 5 and in which said spurious signal preventing means comprises means responsive to the hysterisis effect resulting between signals produced upon paper entering and exiting from the region of said monitor means for generating an unambiguous indicator signal following such exiting.
Claim 9
Dependent Claim
45 words
Bottom margin indicator apparatus as claimed in claim 6 and in which said hysterisis effect responsive means comprises a Schmidt circuit responsive to the output of said monitor means coupled to a one-shot circuit for generating said indicator signal as a pulse of predetermined duration.
Claim 10
Dependent Claim
58 words
Bottom margin indicator apparatus as claimed in claim 4 in which said spurious signal preventing means comprises means operable during the sensing of spurious noise signals resulting from the passage of the bottom edge of the paper by the monitor means for generating an independent unambiguous signal for controlling the indication of the reaching of the bottom margin.
References Cited (Backward Citations)
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