JPH11249829A - Method for compressing bit image data - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a data transfer time between a computer system and a printer controller, and to improve a printing speed by adding a compression processing as against a bit image data string to an ESC/P printer driver using a print-use ESC/P command conversion. SOLUTION: Compression processing as against a bit image data string is added to an ESC/P printer driver using a print-use ESC/P command conversion 4 on a computer system. Besides, a processing 10 for extending the bit image data string is added to a control program on a printer controller so that the bit image data string between the computer system and the printer controller is treated as compression data. By the above configuration, the bit image data string is provided by compression between the computer system and the printer controller under an environment where printing is often executed by a bit image command so that a data transfer time is shortened and also improvement of a printing speed is expected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ESC / P for compressing a bit image data string of a bit image command in an ESC / P which is one of printer control code systems.
The present invention relates to a bit image data compression method.

[0002]

2. Description of the Related Art Table 1 shows the configuration of a bit image command in a conventional ESC / P.

[0003]

[Table 1]

The configuration shown in Table 1 shows the format of a bit image command and the details of the parameters of the bit image command. FIG. 5 shows a bit image data string when the number of dot rows in the vertical direction is 24. In FIG.
The bit sequence of the byte is 2 ⁷ , 2 ⁶ , 2 ⁵ , 2 ⁴ , 2 ³ , 2 ² ,
The order is 2 ¹ , 2 ⁰ . FIG. 2 shows a flow chart of image data printing by ESC / P in a conventional computer apparatus and printer control apparatus in the case of a data string configuration in units of 24 dots in the vertical direction (j = 0).

In the configuration shown in FIG. 6, 4 and 5 are processing on the computer side, and 4 is a
An SC / P printer driver (software on a computer device that converts text, bit image data, etc. into a print ESC / P command) uses a print ESC /
The process 5 converts the print ESC / P command into a P command, and transmits the converted print ESC / P command to the printer control device. Reference numerals 6, 7, and 8 denote processing on the printer control device side. Reference numeral 6 denotes a print ESC / P command transmitted from the computer device. Reference numeral 7 denotes a received print ESC / P command analyzed and converted into image data. Reference numeral 8 denotes a device for expanding the image data to an engine (a device for printing in accordance with a video signal transmitted from the printer control device).

[0006] The conventional technology in the bit image printing by the ESC / P is that, when the bit image data is converted into the bit image command by the ESC / P printer driver, all the bit image data are converted based on the bit image command specifications in Table 1. Converted to a bit image data string.

[0007]

One of the drawbacks of the conventional conversion into a bit image command is that the bit image data string after conversion becomes enormous, so that the printing ESC / P command transmission 5 in FIG. The data transfer time in reception 6 is very long. Accordingly, this affects the time required for printing the bit image data, and the printing speed is significantly reduced as compared with the text data printing.

An object of the present invention is to provide a printing ESC / P shown in FIG.
By adding a compression process for the bit image data sequence to the ESC / P printer driver of the command conversion 4, the bit image data sequence is compressed to shorten the data transfer time between the computer device and the printer control device, thereby improving the printing speed. It is to be.

[0009]

SUMMARY OF THE INVENTION The object of the present invention is to add a compression process for a bit image data string to an ESC / P printer driver on a computer device and to execute a control program (mainly 6, 7 in FIG. 6) on a printer control device. , 8 print ESC / P command reception and analysis, and image data development
This is achieved by adding a decompression process to the compressed bit image data sequence to the software that performs transmission.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a flowchart of bit image data printing to which bit image data string compression processing and expansion processing are added. FIGS. 2 and 3 show flowcharts of the added compression processing and decompression processing, respectively, and FIG. 4 shows an example in which the main compression processing is applied to bit image data.

The compression processing and the expansion processing will be described with reference to the above-mentioned drawings.

As shown in FIG. 1, a conventional bit image data print sequence is added to an ESC /
By adding a process 9 for compressing the bit image data sequence to the P printer driver and a process 10 for expanding the bit image data sequence to the control program on the printer control device, the bit between the computer device and the printer control device can be obtained. Handles image data strings as compressed data.

Focusing on the bit image data sequence in the bit image data sequence shown in FIG. 2, the column data in the vertical direction is subjected to pattern matching, and the matched column data is compressed by the number of times of matching. That is, at the time of conversion to a bit image command, the first data of the bit image data string is set (first data setting 11 of the bit image data string), and the column data for pattern matching is set to pattern 1 for j bytes (the pattern matching column). Data setting 12), and the data of pattern 1 as pattern matching data is stored in an image buffer for buffering the compressed data (pattern matching column data storage 13). Then, the next column data is set in pattern 2 for j bytes (next column data setting 14), and the contents of pattern 1 and pattern 2 are compared (pattern content judgment 1).
5) If the result is equal, the matching counter is increased by one (matching counter increase 16), and the next column data storage 1
Repeat from 4, but if they are not equal, it is determined whether the matching counter value is 0 or more (matching counter value determination 1
7). If it is 0 or more, it is determined that there is matching data,
Pattern matching data indicating compressed data at the time of decompression is stored in the image buffer (same as 13), and a matching counter indicating the number of times of matching is stored (matching counter storage 18). No processing because it was not data. Finally, the end of the bit image data sequence is determined (bit image data sequence end determination 19). If not completed, the process is repeated from the pattern matching column data storage 12, otherwise, the bit image data sequence compression processing is performed. To end.

In the bit image data string expansion processing shown in FIG. 3, after receiving the bit image command, the first data of the bit image data string is set (the first data setting 20 of the bit image data string), and the column data for pattern matching is set. The pattern is set to j bytes of pattern 1 (pattern matching column data setting 21), and the data of pattern 1 as pattern matching data is stored in an image buffer for buffering decompressed data (pattern matching column data storage 22). Then, the next column data is set in pattern 2 for j bytes (next column data setting 2).
3) Compare the contents of pattern 1 and pattern 2 (pattern content judgment 24), and if they are equal, store the pattern matching data in the image buffer (pattern matching column data storage 25) and set the matching counter to 1
(Matching counter decrement 26), it is determined whether the matching counter value is 0 or more (matching counter value determination 27). If it is 0 or more, the pattern matching sequence data storage 25 is repeated. Otherwise, the pattern 1 is decompressed. Since the processing has been completed, the end of the bit image data string is determined (bit image data string end determination 28). If they are not equal to each other, the end of the bit image data sequence is determined in the same manner as described above because the pattern 2 does not mean compressed data. If not, the process is repeated from the pattern matching column data storage 21; End the column expansion process.

(1) Example of application to bit image data <Conditions> Paper size: A4 Resolution: 180 DPI (Dot / Inch) (2) Application to bit image data Data capacity for A4 full-bit image data: 2
88 kbytes Theoretical value in bit image data compression Best: 1 kbyte (0.1% compression ratio) Worst: 337 kbytes (117% compression ratio, conversely 17
Table data: 30 kbytes (10% compression ratio) Figure: 70 kbytes (24% compression ratio) Photo: 245 kbytes (85% compression ratio) Here, bit image When the actual compression processing is applied to the data, the result as shown in FIG. 4 is obtained before and after the compression. The experimental value of the theoretical value in the above (2) bit image data compression after the application of the main compression processing has a high compression ratio. You can see that it is done. This is particularly noticeable in tabular data.

[0016]

According to the present invention, in an environment where printing is frequently performed by using an ESC / P bit image command, a bit image data string can be compressed and held between a computer device and a printer control device. It is possible to shorten the data transfer time and improve the printing speed.

Further, according to the present invention, in the case of data having a relatively large number of the same bit images in the horizontal direction (such as table data), the compression rate is extremely high, and the data transfer time can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a flowchart of bit image data printing according to an embodiment of the present invention.

FIG. 2 is a flowchart of a bit image data string compression process.

FIG. 3 is a flowchart of a bit image data string extension process.

FIG. 4 is an example of application of the present compression processing to bit image data.

FIG. 5 is a diagram showing a bit image data string in ESC / P.

FIG. 6 is a flowchart of bit image data printing.

[Explanation of symbols]

4 ESC / P command conversion for printing, 5 ESC / P command transmission for printing, 6 ESC / P command reception for printing, 7 ESC / P command analysis for printing
Image data expansion, 8 ... Image data transmission, 9 ... Bit image data string compression, 10 ... Bit image data string expansion, 11 ... Bit image data string head data setting, 12 ... Pattern Column data setting for matching (pattern 1), 13 ... Column data storage for pattern matching (image buffer), 14 ... Next column data setting (pattern 2), 15 ... Pattern content judgment, 16 ... : Matching counter increase, 17: Matching counter value judgment, 18: Matching counter storage, 19: Bit image data string end judgment,
20 ··· Start data setting of bit image data string
21: pattern matching column data setting (pattern 1), 22: pattern matching column data storage (image buffer), 23: next column data setting (pattern 2), 24: pattern content judgment , 25 ... Pattern matching column data storage (image buffer), 26 ... Matching counter decrement, 27 ... Matching counter value judgment, 28 ... Bit image data string end judgment.

Claims (2)

[Claims] 1. An ESC / P of a printer control code system, wherein a bit image data string of a bit image command of the ESC / P is compressed.
SC / P bit image data compression method. 2. The method according to claim 1, wherein the bit image data sequence of the bit image command of the ESC / P is compressed by using column data in a vertical direction as a pattern and column data having the same contents on the same line. ESC / P bit image data compression method.