Claims
- 1. A thermal gradation printing apparatus comprising:
- a thermal head including a body portion, a substrate formed on said body portion, and a plurality of heat elements arranged in a line on said substrate;
- head temperature detecting means for detecting the temperature of said body portion;
- data generating means for generating a plurality of data units depending on density data units;
- accumulated heat amount estimating means for estimating accumulated heat amounts of regions of said substrate for every one line, the regions corresponding to said plurality of heat elements, respectively;
- correction value calculating means for calculating correction values assigned to said plurality of heat elements, respectively, based on the estimated accumulated heat amounts, and the temperature of said body portion;
- data correcting means for correcting the plurality of data units based on the correction values; and
- head driving means for allowing said plurality of heat elements to heat in accordance with the corrected data units,
- wherein the correction value is represented by n bits, and wherein said data correcting means includes: comparing means for comparing a value represented by lower m bits of the correction value with a reference value, and for generating an output value, the output value having one of a first value when the value represented by the lower m bits is larger than the reference value and a second value when the value represented by the lower m bits is equal to or smaller than the reference value; reference value setting means for setting the reference value for each line; adding means for adding the output value from said comparing means to a value represented by upper (n-m) bits of the correction value, to generate a sum; and multiplying means for multiplying the sum by the plurality of data units generated by said data generating means, said reference value setting means setting different values for 2.sup.m lines, respectively.
- 2. A thermal gradation printing apparatus comprising:
- a thermal head including a body portion, a substrate formed on said body portion, and a plurality of heat elements arranged in a line on said substrate;
- head temperature detecting means for detecting the temperature of said body portion;
- data generating means for generating a plurality of data units depending on density data units;
- accumulated heat amount estimating means for estimating accumulated heat amounts of regions of said substrate for every one line, the regions corresponding to said plurality of heat elements, respectively;
- correction value calculating means for calculating correction values assigned to said plurality of heat elements, respectively, based on the estimated accumulated heat amounts, and the temperature of said body portion;
- data correcting means for correcting the plurality of data units based on the correction values; and
- head driving means for allowing said plurality of heat elements to heat in accordance with the corrected data units,
- wherein the correction value is represented by n bits, and wherein said data correcting means includes: comparing means for comparing a value represented by lower m bits of the correction value with a reference value, and for generating an output value, the output value having one of a first value when the value represented by the lower m bits is larger than the reference value and a second value when the value represented by the lower m bits is equal to or smaller than the reference value; reference value setting means for setting the reference value for each line; and adding means for adding the output value from said comparing means, a value represented by upper (n-m) bits of the correction value, and the plurality of data units generated by said data generating means to each other, said reference value setting means setting different values for 2.sup.m lines, respectively.
Priority Claims (2)
Number |
Date |
Country |
Kind |
4-324524 |
Dec 1992 |
JPX |
|
5-115484 |
May 1993 |
JPX |
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Parent Case Info
This is a division of copending application Ser. No. 08/160,032, filed Nov. 30, 1993 now U.S. Pat. No. 5,644,351.
US Referenced Citations (5)
Foreign Referenced Citations (7)
Number |
Date |
Country |
298456 |
Apr 1990 |
JPX |
2217267 |
Aug 1990 |
JPX |
2241760 |
Sep 1990 |
JPX |
2248264 |
Oct 1990 |
JPX |
2289364 |
Nov 1990 |
JPX |
324972 |
Feb 1991 |
JPX |
435961 |
Feb 1992 |
JPX |
Non-Patent Literature Citations (1)
Entry |
Yamashita et al., The Journal of the Institute of Image Electronics Engineers of Japan, vol. 22, No. 1, pp. 20-26, "Density Compensating Method to Compensate Dynamic Heat Accumulations for Dye Transfer Printing." |
Divisions (1)
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Number |
Date |
Country |
Parent |
160032 |
Nov 1993 |
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