US4694353A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital scanner
Assignee: Ricoh Co Ltd
•
Filing: 1985-12-04
•
Granted: 1987-09-15
•
Expires: 2005-12-04
Abstract
Abstract A digital scanner installed in an image reader of a digital facsimile apparatus, a digital copier or the like includes an analog-to-digital converter for quantizing a video signal which is produced by reading a document. A threshold voltage applied to the analog-to-digital converter from the outside is variable and specified from the outside.
Inventors
- 👤 Tsutomu Sato
- 👤 Noboru Murayama
- 👤 Key Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:12
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/403
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
221 words
A scanner for reading and quantizing images on a document in multiple tones, comprising: a photoelectric transducer for reading the images and photoelectrically converting the images to produce an electrical signal; means for producing two digital signals for specifying an upper threshold voltage level and a lower threshold voltage level; a first latch means and a second latch means connected to said means for producing two digital signals for receiving said two digital signals and for storing said signals therein; two digital-to-analog converters, each connected to a respective latch means for receiving said digital signals and for converting said digital signals to an upper threshold voltage level signal and a lower threshold voltage level signal; an analog-to-digital converter connected to said digital-to-analog converters and to said photoelectric transducer for receiving said electrical signal at a signal input terminal, said upper threshold voltage level signal at an upper threshold input terminal and said lower threshold voltage level signal at a lower threshold input terminal; wherein the means for producing two digital signals is constructed to determine a regular upper and a regular lower threshold voltage level for reading the image next time, based on data produced by reading a single line or a plurality of lines of the images with respect to a particular upper and a particular lower threshold voltage level.
Claim 2
Dependent Claim
221 words
A scanner for reading and quantizing images on a document in multiple tones, comprising: a photoelectric transducer for reading the images and photoelectrically converting the images to produce an electrical signal; means for producing two digital signals for specifying an upper threshold voltage level and a lower threshold voltage level; a first latch means and a second latch means connected to said means for producing two digital signals for receiving said two digital signals and for storing said signals therein; two digital-to-analog converters, each connected to a respective latch means for receiving said digital signals and for converting said digital signals to an upper threshold voltage level signal and a lower threshold voltage level signal; an analog-to-digital converter connected to said digital-to-analog converters and to said photoelectric transducer for receiving said electrical signal at a signal input terminal, said upper threshold voltage level signal at an upper threshold input terminal and said lower threshold voltage level signal at a lower threshold input terminal; wherein the means for producing two digital signals is constructed to determine a regular upper and a regular lower threshold voltage level for reading the image next time, based on data produced by reading a single line or a plurality of lines of the images with respect to a particular upper and a particular lower threshold voltage level.
Claim 3
Dependent Claim
187 words
A scanner for reading and quantizing images on a document in multiple tones, comprising: a photoelectric transducer for reading the images and photoelectrically converting the images to produce an electrical signal; means for producing two digital signals for specifying an upper threshold voltage level and a lower threshold voltage level; a first latch means and a second latch means connected to said means for producing two digital signals for receiving said two digital signals and for storing said signals therein; two digital-to-analog converters, each connected to a respective latch means for receiving said digital signals and for converting said digital signals to an upper threshold voltage level signal and a lower threshold voltage level signal; an analog-to-digital converter connected to said digital-to-analog converters and to said photoelectric transducer for receiving said electrical signal at a signal input terminal, said upper threshold voltage level signal at an upper threshold input terminal and said lower threshold voltage level signal at a lower threshold input terminal; wherein the means for producing is constructed to vary the upper and the lower threshold voltages for reading the same line or same document.
Claim 4
Dependent Claim
187 words
A scanner for reading and quantizing images on a document in multiple tones, comprising: a photoelectric transducer for reading the images and photoelectrically converting the images to produce an electrical signal; means for producing two digital signals for specifying an upper threshold voltage level and a lower threshold voltage level; a first latch means and a second latch means connected to said means for producing two digital signals for receiving said two digital signals and for storing said signals therein; two digital-to-analog converters, each connected to a respective latch means for receiving said digital signals and for converting said digital signals to an upper threshold voltage level signal and a lower threshold voltage level signal; an analog-to-digital converter connected to said digital-to-analog converters and to said photoelectric transducer for receiving said electrical signal at a signal input terminal, said upper threshold voltage level signal at an upper threshold input terminal and said lower threshold voltage level signal at a lower threshold input terminal; wherein the means for producing is constructed to vary the upper and the lower threshold voltages for reading the same line or same document.
Claim 5
Dependent Claim
168 words
A scanner for reading and quantizing images on a document in multiple tones, comprising: a photoelectric transducer for reading the images and photoelectrically converting the images to produce an electrical signal, means for producing a digital signal for specifying a threshold voltage level; a latch means connected to said means for producing a digital signal for receiving a digital signal and for storing said signals therein; a digital-to-analog converter connected to said latch means for receiving said digital signal and for converting said digital signal to a threshold voltage level signal; comparator means connected to said photoelectric transducer and said digital-to-analog converter for receiving said electrical signal and said threshold voltage signal and for producing an output as a result of the comparison of the two signals; wherein said means for producing a digital signal is constructed to vary a level of the threshold voltage applied to the comparator in order to read a same line of the images or a same document a plurality of consecutive times.
Claim 6
Dependent Claim
168 words
A scanner for reading and quantizing images on a document in multiple tones, comprising: a photoelectric transducer for reading the images and photoelectrically converting the images to produce an electrical signal, means for producing a digital signal for specifying a threshold voltage level; a latch means connected to said means for producing a digital signal for receiving a digital signal and for storing said signals therein; a digital-to-analog converter connected to said latch means for receiving said digital signal and for converting said digital signal to a threshold voltage level signal; comparator means connected to said photoelectric transducer and said digital-to-analog converter for receiving said electrical signal and said threshold voltage signal and for producing an output as a result of the comparison of the two signals; wherein said means for producing a digital signal is constructed to vary a level of the threshold voltage applied to the comparator in order to read a same line of the images or a same document a plurality of consecutive times.
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) | 1990-09-14 | 1991-03-16 | 1991-09-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-09-14 | 1995-03-16 | 1995-09-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-09-14 | 1999-03-16 | 1999-09-15 | $7700.00 | Window Closed / Lapsed |