US4374626A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Erasing typewriter with automatic/manual selection
Assignee: IBM Information Products Corp
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Filing: 1980-04-18
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Granted: 1983-02-22
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Expires: 2000-04-18
Abstract
Abstract An automatic erasing typewriter determines, in response to actuation of an erase key, if automatic erasing is possible. If not, the typewriter terminates the erase cycle with a backspace and conditions the typewriter for manual erase. Actuation of a character key as the next actuated key completes the manual erase. Actuation of a key other than a character key deconditions the manual erase.
Inventors
- 👤 Robert W. Hooker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 01:40
CPC Classifications
B; B41; B41J; B41J5/00; B41J5/30; B41J5/44; B41J5/46; B41J29/00; B41J29/26; B41J29/36
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
261 words
In an erasing typewriter including key actuated means for generating signals representing an actuated key, memory means for storing an ordered sequence of signals representing a sequence of operator actuated keys, print means including print and erase media for executing a print cycle to at times print a character at a print point if said print medium is enabled, or to erase a character at a print point if said erase medium is enabled, print point position control means responsive to said key actuated means for displacing said print means and for accessing a selected location of said memory means corresponding to said print point, and erase means operative in response to actuation of an erase key for initiating a sequence of operations including: (a) actuating said print point position control means to displace said print point one character space toward a left margin, (b) accessing said memory means at a selected location corresponding to said displaced print point for reading signals stored at said selected location, (c) actuating said print means and enabling said erase medium to execute a print cycle to erase a character at said print point corresponding to signals read from said memory means, the improvement comprising: first means responsive to absence of signals representing an erasable character at said selected location of said memory means to inhibit said print cycle and to enable said erase medium and said print means to execute a print cycle on a following key actuation only if said following key actuation corresponds to actuation of a key representing an erasable character.
Claim 2
Dependent Claim
261 words
In an erasing typewriter including key actuated means for generating signals representing an actuated key, memory means for storing an ordered sequence of signals representing a sequence of operator actuated keys, print means including print and erase media for executing a print cycle to at times print a character at a print point if said print medium is enabled, or to erase a character at a print point if said erase medium is enabled, print point position control means responsive to said key actuated means for displacing said print means and for accessing a selected location of said memory means corresponding to said print point, and erase means operative in response to actuation of an erase key for initiating a sequence of operations including: (a) actuating said print point position control means to displace said print point one character space toward a left margin, (b) accessing said memory means at a selected location corresponding to said displaced print point for reading signals stored at said selected location, (c) actuating said print means and enabling said erase medium to execute a print cycle to erase a character at said print point corresponding to signals read from said memory means, the improvement comprising: first means responsive to absence of signals representing an erasable character at said selected location of said memory means to inhibit said print cycle and to enable said erase medium and said print means to execute a print cycle on a following key actuation only if said following key actuation corresponds to actuation of a key representing an erasable character.
Claim 3
Dependent Claim
39 words
The apparatus of claim 1 in which said first means includes latch means set to a distinctive condition only when said erase key is actuated and said selected location of said memory means does not contain an erasable character.
Claim 4
Dependent Claim
31 words
The apparatus of claim 2 which includes input means to set said latch means if said memory means contains signals representing a typewriter function or is empty at said selected location.
Claim 5
Independent Claim
39 words
The apparatus of claims 2 or 3 which includes logic means distinctively operated in response to depression of a printable character key when said latch means is set to execute an erase function and to reset said latch means.
Claim 6
Independent Claim
37 words
The apparatus of claims 2 or 3 which includes logic means distinctively operated if a typewriter function key is depressed when said latch means is set to execute a corresponding function and to reset said latch means.
Claim 7
Independent Claim
40 words
The apparatus of claims 2 or 3 which includes logic means distinctively operated if a typewriter space bar is depressed when said latch means is set to execute a no print, no escape cycle and to reset said latch means.
Claim 8
Dependent Claim
37 words
The apparatus of claim 2 or 3 which includes logic means distinctively operated if said erase key is depressed when said latch means is set to initiate an automatic erase cycle and to reset said latch means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-02-21 | 1986-08-23 | 1987-02-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-02-21 | 1990-08-23 | 1991-02-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-02-21 | 1994-08-23 | 1995-02-22 | $7700.00 | Window Closed / Lapsed |