US5099258A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dot print density regulating circuit
Assignee: Seiko Instruments Inc
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Filing: 1990-08-20
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Granted: 1992-03-24
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Expires: 2010-08-20
Abstract
Abstract In order to avoid density variation due to difference of a print dot rate in a line printer for printing an image and character, a data transfer circuit operates to convert image data inputted through a buffer memory into a plurality of serial data trains. The serial data trains are fed to corresponding shift registers of a print head. The data transfer circuit is also connected to a selecting gate circuit in the form of a demultiplexer. The demultiplexer operates to cyclicly sample the plurality of serial data trains outputted from the data transfer circuit. A counter counts a number of print dots contained in the sampled data so as to measure a print dot rate. A drive pulse width is adjusted according to the print dot rate so as to avoid variation of print density due to difference of the print dot rate.
Inventors
- 👤 Yoshihiko Hirayama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:36
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/315; B41J2/32; B41J2/35; B41J2/355; B41J2/36
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
107 words
In a line printer having a print head composed of a plurality of dot-forming elements arranged lineary along widthwise of a print paper sheet for printing an image and character according to print data, the improvement comprising: a data transfer circuit for transferring a plurality of serial print data trains to the print head; a demultiplexer for selectively sampling the serial print data trains from the data transfer circuit; a counter for counting the sampled data so as to determine a print dot rate; and means for adjusting a width of drive pulses applied to the print head so as to compensate for the print dot rate.
Claim 2
Dependent Claim
107 words
In a line printer having a print head composed of a plurality of dot-forming elements arranged lineary along widthwise of a print paper sheet for printing an image and character according to print data, the improvement comprising: a data transfer circuit for transferring a plurality of serial print data trains to the print head; a demultiplexer for selectively sampling the serial print data trains from the data transfer circuit; a counter for counting the sampled data so as to determine a print dot rate; and means for adjusting a width of drive pulses applied to the print head so as to compensate for the print dot rate.
Claim 3
Dependent Claim
31 words
A line printer according to claim 1; wherein said means includes a memory which stores a table effective to determine the width of drive pulses according to the print dot rate.
Claim 4
Dependent Claim
23 words
A line printer according to claim 1; including means for shifting a sampling position of the print data for each line printing operation.
Claim 5
Dependent Claim
151 words
In a line printer comprising a print head having a plurality of dot-forming elements arranged linearly along a width of a print paper sheet for printing image and character data; said printer including a data transfer circuit for transferring a plurality of serial print data trains to the print head and a print rate compensating circuit for reducing variation in print density caused by differences in print rates, said compensating circuit comprising: a demultiplexer for receiving outputs from said data transfer circuit and for selectively sampling the serial print data trains from the data transfer circuit; a counter for receiving an output from the demultiplexer and for counting sampled data to determine a print dot rate; and adjusting means for adjusting widths of drive pulses based on said print dot rate so as to provide an optimum pulse width for the print dot rate and thereby reduce variation in print density.
Claim 6
Dependent Claim
151 words
In a line printer comprising a print head having a plurality of dot-forming elements arranged linearly along a width of a print paper sheet for printing image and character data; said printer including a data transfer circuit for transferring a plurality of serial print data trains to the print head and a print rate compensating circuit for reducing variation in print density caused by differences in print rates, said compensating circuit comprising: a demultiplexer for receiving outputs from said data transfer circuit and for selectively sampling the serial print data trains from the data transfer circuit; a counter for receiving an output from the demultiplexer and for counting sampled data to determine a print dot rate; and adjusting means for adjusting widths of drive pulses based on said print dot rate so as to provide an optimum pulse width for the print dot rate and thereby reduce variation in print density.
Claim 7
Dependent Claim
28 words
The line printer of claim 4, wherein the pulse width is determined from a table which determines the width of drive pulse according to the print dot rate.
Claim 8
Dependent Claim
55 words
The line printer of claim 4, wherein the adjusting means includes means for determining the width of drive pulses based upon a product of a compensative coefficient and a timer constant and wherein the compensative coefficient varies according to counted values output by the counter and the timer constant varies according to a gradation level.
References Cited (Backward Citations)
US4661703A
Cited
US4777536A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-03-24 | 1995-09-23 | 1996-03-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-03-24 | 1999-09-23 | 2000-03-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-03-24 | 2003-09-23 | 2004-03-24 | $7700.00 | Window Closed / Lapsed |