Data compression method and print processing device utilizing the same
First Claim
1. A data compression method, comprising the steps of:
- (a) repeatedly and preliminarily compressing a first preset amount of first data, using each of plural different compression techniques and storing the compressed first data corresponding to each said different compression technique;
(b) computing compression ratios corresponding to the respective compression techniques and storing the compression ratios;
(c) comparing all the stored compression ratios to each other to determine an optimum compression technique corresponding to the smallest of the stored compression ratios from among the plural different compression techniques, after the compression ratios have been computed and stored for all the compression techniques;
(d) compressing a second amount of second data, which amount is larger than the first amount, using the optimum compression technique; and
(e) repeating said steps (a) through (d) for succeeding data whenever the data compression of the second data is completed until data compression of all data to be compressed is completed.
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Accused Products
Abstract
A printing data transmitted from a host computer is stored in a receiving buffer. An editorial unit receives the printing data in the receiving buffer in each one line and writes into a page buffer after compressed. An expansion unit reads out the printing data in the page buffer and deploys them into a band buffer as a raster data. An engine unit performs printing in accordance with the raster data in the band buffer. The editorial unit compresses the printing data of each line up until the preset line N with plural types of compression techniques and computes compression rates for each line. A compression technique to be applied is determined in accordance with the compression rates. The printing data of each line up until those of the preset line X are compressed by the determined compression technique. A determination of the compression technique is repeated in every completion of the printing data processing for the X lines.
94 Citations
32 Claims
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1. A data compression method, comprising the steps of:
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(a) repeatedly and preliminarily compressing a first preset amount of first data, using each of plural different compression techniques and storing the compressed first data corresponding to each said different compression technique; (b) computing compression ratios corresponding to the respective compression techniques and storing the compression ratios; (c) comparing all the stored compression ratios to each other to determine an optimum compression technique corresponding to the smallest of the stored compression ratios from among the plural different compression techniques, after the compression ratios have been computed and stored for all the compression techniques; (d) compressing a second amount of second data, which amount is larger than the first amount, using the optimum compression technique; and (e) repeating said steps (a) through (d) for succeeding data whenever the data compression of the second data is completed until data compression of all data to be compressed is completed. - View Dependent Claims (2, 3, 4)
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5. A data compression method, comprising the steps of:
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(a) repeatedly and preliminarily compressing first line data of each line of a first preset number of plural lines, using for each line a plurality of different compression techniques, and storing the compressed line data corresponding to each said different compression technique; (b) computing for each line compression ratios corresponding to the respective compression techniques and storing the compression ratios; (c) comparing, for each line, all the compression ratios to each other to determine separately for each line which of the plural compression techniques corresponds to the smallest of the compression ratios, after the compression ratios have been computed and stored for all the compression techniques; (d) after said step (c), counting for each compression technique a number of times the compression technique corresponds to the smallest of the compression ratios; (e) determining an optimum compression technique from among the plural compression techniques in accordance with the counted numbers for the respective compression techniques, after the compression ratios have been computed and stored for all the compression techniques; (f) compressing second line data of a second preset number of plural lines following the first preset number of plural lines, using the optimum compression technique, the second preset number being larger than the first preset number; and (g) repeating said steps (a) through (f) for succeeding line data whenever the data compression of the second line data is completed until compression for all line data to be compressed is completed. - View Dependent Claims (6, 7, 8, 9, 10, 11)
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12. A system that performs data compression, comprising:
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(a) first compressing means for repeatedly and preliminarily compressing a preset first amount of first data, using plural different compression techniques; (b) first storage means for storing the compressed first data corresponding to each said different compression technique; (c) computing means, coupled to the first compressing means, for computing compression ratios corresponding to the respective compression techniques; (d) second storage means for storing the compression ratios; (e) comparing means, coupled to the computing means, for comparing all the stored compression ratios to each other to determine an optimum compression technique corresponding to the smallest of the stored compression ratios from among the plural compression techniques, after the compression ratios have been computed and stored for all the data compression techniques; (f) second compressing means, coupled to the comparing means, for compressing a second amount of second data, which amount is larger than the first amount, using the optimum compression technique; and (g) controlling means for controlling the first compressing means, the computing means, the comparing means, and the second compressing means for repeated determination and application of the optimum data compression technique whenever the data compression of the second data is completed until data compression of all data to be compressed is completed. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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21. A system that compresses lines of data, comprising:
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(a) first compressing means for repeatedly and preliminarily compressing first data, including a first predetermined number of plural lines of data, the first compressing means repeatedly and tentatively compressing each line of the first predetermined number of plural lines, using plural different compression techniques; (b) first storage means for storing the compressed first data corresponding to each said different compression technique; (c) computing means for computing for each line compression ratios corresponding to the respective compression techniques; (d) second storage means for storing the compression ratios; (e) comparing means, coupled to the computing means, for comparing all the compression ratios for each line of said predetermined number of lines to determine the smallest compression ratio for each of the plural lines, after the compression ratios have been computed and stored for all the data compression techniques; (f) counting means for counting, separately for each compression technique, a number of lines for which the smallest compression ratio corresponds to said each compression technique; (g) determining means, coupled to the computing means, for determining an optimum compression technique from among the plural compression techniques in accordance with the counted numbers; (h) second compressing means, coupled to the determining means, for compressing second line data of a second predetermined number of plural lines following the first predetermined number of plural lines, using the optimum compression technique, the second predetermined number being larger than the first predetermined number; and (I) controlling means for controlling the first compressing means, the computing means, the determining means, and the second compressing means for repeated determination and application of the optimum data compression technique whenever the data compression of the second data is completed until data compression of all data to be compressed is completed. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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Specification