Patent US4449137A successfully refreshed from Google Patents.
US4449137A
Expired / Lapsed
US
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Driving method for thermal recording head
Assignee: Fujifilm Business Innovation Corp
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Filing: 1982-03-23
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Granted: 1984-05-15
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Expires: 2002-03-23
Abstract
Abstract A thermal recording method which prevents recording density defects includes preheating the heating elements of the thermal recording head during a time when printing is not carried out. Particularly, the head may be preheated during times when a line is not printed, as between adjacent character lines of a printed or typed document, to prevent recording density deterioration of the next printed line.
Inventors
- 👤 Toshiharu Inui
- 👤 Haruhiko Moriguchi
- 👤 Takashi Ohmori
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:35
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/315; B41J2/32; B41J2/35; B41J2/355; B41J2/36; G; G01; G01D; G01D15/00; G01D15/10
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
87 words
In a method of driving a thermal recording head of a thermal recorder which is provided with a plurality of heating elements actuated selectively according to a picture signal, the improvement comprising; examining a picture signal of each line to discriminate whether it includes information to be printed, and preheating said heating elements by driving them up to a predetermined temperature only when said picture signal contains no information to be printed, said predetermined temperature being selected so as to be less than a thermal recording temperature.
Claim 2
Dependent Claim
87 words
In a method of driving a thermal recording head of a thermal recorder which is provided with a plurality of heating elements actuated selectively according to a picture signal, the improvement comprising; examining a picture signal of each line to discriminate whether it includes information to be printed, and preheating said heating elements by driving them up to a predetermined temperature only when said picture signal contains no information to be printed, said predetermined temperature being selected so as to be less than a thermal recording temperature.
Claim 3
Dependent Claim
25 words
A method as claimed in claim 1, wherein said preheating comprises directing a preheating driving pulse to said recording head to heat said heating elements.
Claim 4
Dependent Claim
24 words
A method as claimed in claim 2, wherein said pulse is of a duration substantially smaller than that used to record a picture signal.
Claim 5
Dependent Claim
29 words
A method as claimed in claim 1, wherein said preheating step comprises driving said heating elements with a current substantially smaller than that used to record a picture signal.
Claim 6
Dependent Claim
28 words
A method as claimed in claim 1, wherein said examining step includes counting black signals comprising signals to be printed, from among picture signals input for each line.
Claim 7
Dependent Claim
43 words
A method as claimed in claim 5, wherein, upon detecting no black signals, a picture signal according to said line is inverted, and applied to one input of the recording head, so as to enable all of said heating elements to be preheated.
References Cited (Backward Citations)
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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) | 1987-05-15 | 1987-11-14 | 1988-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-15 | 1991-11-14 | 1992-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-15 | 1995-11-14 | 1996-05-15 | $7700.00 | Window Closed / Lapsed |