JP3156379B2 - How to compress print data - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a server system connected to a printing apparatus which fetches print data to which a print control code is added and performs printing in a format specified by the print control code, and executes an application program. hand,
In a computer system integrated by a line control mechanism with a client system that requests printing from a printing device of the server system, when the client system prints to a printing device of each server system via a line, The present invention relates to a method for compressing image data included in print data.

In recent years, on a computer system integrated by a line control mechanism, a variety of printing devices (hereinafter, sometimes referred to as printer devices) are connected as a server system, and a plurality of computer systems ( Client system) (hereafter referred to as a shared printer device), but print processing via a line has inferior print response performance compared to print processing to a directly connected printer device. The transfer time needs to be reduced.

When printing is performed on the shared printer, print data is generally temporarily stored in an auxiliary storage device such as a hard disk device (hereinafter, referred to as a spool). In addition, it is necessary to minimize the amount of data to be stored so as not to stress the disk resources.

In order to provide an output function to a shared printer via a line as described above, improvement of print response performance and reduction of disk resources are indispensable conditions. There is a demand for a method of efficiently compressing the data.

[0005]

2. Description of the Related Art FIGS. 3 and 4 are views for explaining a conventional print data compression method. FIG. 3 shows an example of the configuration of a computer system, and FIG. 4 shows an example of the data format of a printer. Is shown.

As shown in FIG. 3, a client system
The application program 10 running on 1
When an output is made to a printer device (virtual printer) 11 virtually connected to the computer system 1, the data is transferred to the server system 2 via the line 3 and shared there.
Output to 22.

However, the application program 10
Since the print data output to the printer device 11 includes a bit image, the amount of data flowing through the line 3 and the amount of data stored in the spool 20 of the server system 2 become enormous.

Therefore, in general, a client system
Although the compression / transmission unit 12a provided in 1 performs the compression processing of the print data to reduce the data amount, the conventional method is the same for print data to any printer device 22. Since the compression method is applied, the compression ratio may be extremely lowered or the compression processing time may increase depending on print data.

Hereinafter, a specific description will be given with reference to FIG.
FIG. 4A shows an example of rectangular image data for a laser beam printer system, and FIG. 4B shows an example of printer head image data for a serial printer system.

In the case of rectangular image data, since the printing device (laser beam printer device) has a mechanism for printing the image data developed on the bitmap memory as it is, the application program 10 is generated. As shown in the figure, the print data to be generated is generated in such a manner that data on the bitmap memory is arranged next to the print control code, for example, in units of 4 bytes.

In the case of printer head image data, as shown in the figure, the print control code is followed by the number of dots of the serial printer head.
For example, print data in units of 3 bytes for 24 dots are arranged.

Normally, for the rectangular image data,
For example, it is compressed in units of 4 bytes. In this case,
"0" is "4 bytes", "1" is "4 bytes", "0"
Is compressed to "4" bytes. However,
The data compression is performed when the same data continues, for example, for 2 bytes or more.

When this compression method is applied to the printer head image data, for example, in the case of the print data shown in the figure, “0” is “1 byte”, “1” is “1 byte”, and “0” is “1 byte”. "2 bytes", "1" is "1 byte"
Data compression such as .. is performed.

In this case, efficient data compression is performed on rectangular image data, but efficient data compression is not always performed on printer head image data.

Since the printer head image data is transferred in 3-byte units of 24 dots held by the printer head, for example, 3 bytes (24 dots) )
It is efficient to perform data compression in units, for example, data compression such that “00FF00” continues “4” times in the illustrated example.

However, in the conventional method, the same compression method is applied to print data of any printer. This is because various types of printing apparatuses are rarely connected to the computer system integrated by the conventional line control mechanism, and there is no idea of performing data compression for each printer apparatus.

[0017]

Accordingly, 1) the problem that the compression ratio for specific print data is reduced and the print processing time caused by the increase of the compression processing time is increased, and 2) the compression for specific print data is There is a problem that the storage amount on the spool caused by the decrease in the rate increases, the capacity of the spool must be increased, and the disk resources increase.

In view of the above-mentioned conventional disadvantages, the present invention relates to a computer system in which a printing apparatus that fetches print data to which a print control code is added and prints the data is connected and integrated by a line control mechanism. An object of the present invention is to provide a data compression method capable of improving the performance of a computer system and reducing resources for compressing image data included in print data when performing printing on an apparatus. It is.

[0019]

FIG. 1 is a diagram illustrating the principle of the present invention. The above problem is solved by a data compression method configured as follows.

A server system 2 to which a printing device 22 for receiving print data to which a print control code is added and performing printing in a format specified by the print control code is connected.
And the client system 1 that executes the application program 10 and requests the printing device 22 of the server system 2 to perform printing, in the computer system integrated by the line control mechanism, the client system 1
Is connected to the printing device 2 of the server system 2 via the line 3.
2 is a method of compressing image data included in print data when performing printing on the client system 1 according to the data format of each printing device 22 provided in each server system 2. Types of compression processing units 120,12
And print control codes of the print data output from the application program 10 and select the compression processing unit 120 or 121, according to the data format of the printing device 22 to be output. The image data compression method is dynamically changed according to the printing device 22 to be output.

[0021]

That is, according to the print data compression method of the present invention, the type of the printer device 22 included in each server system 2 is set so that the compression / transmission unit 12a shown in FIG. Paying attention to different data streams, print data compression adapted to the data stream is performed for each data stream.

FIG. 1 is a diagram illustrating the principle of the present invention. In the figure, reference numeral 10 denotes an application program, which outputs print data including a bit image corresponding to the printer device 22 that issues a print request. Reference numeral 13 denotes a print control code analysis unit. The print control code analysis unit 13 analyzes a print control code of print data output from the application program 10 and selects a compression method that can perform the most efficient compression processing. , And 12 respectively, and the corresponding compression processing sections 120, 121,... Perform data compression corresponding to the data format specified by the print control code. The print data compressed by the individual compression processing units 120, 121,... Is output to the shared printer 22 of each server system 2 via the line 3.

Accordingly, in the present invention, as shown in FIG. 1, the print control code analysis section 12 analyzes the print control code of the print data, and applies the most efficient compression method for the print data by the print control code. Therefore, the print data can be efficiently compressed regardless of the output to any printer device 22.

[0024]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is an explanatory view of the principle of the present invention.
FIG. 1 is a view schematically showing one embodiment of the present invention.

According to the present invention, a server system 2 to which a printing device 22 that fetches print data to which a print control code is added and performs printing in a format indicated by the print control code is connected, and an application program 10.
And the client system 1 that requests the printing device 22 of the server system 2 to perform printing, the data format of each printing device 22 provided in each server system 2 in the computer system integrated by the line control mechanism. In response to this, a plurality of types of compression processing units 120, 121,... Are provided in the client system 1 to analyze the print control code of the print data output from the application program 10, and to output the data format of the printing Means for selecting the compression processing unit 120 or 121,... And dynamically changing the compression method of the image data according to the printing device 22 to be output. It is a necessary means. Note that the same reference numerals indicate the same object throughout the drawings.

Hereinafter, a method of compressing print data according to the present invention will be described with reference to FIG. 2 while referring to FIG. FIG. 2 is a diagram schematically showing one embodiment of the present invention, showing an example of print data compression processing.

In this figure, (a) shows an example of rectangular image data used in a laser beam printer system, and (b) shows an example of printer head image data used in a serial printer system. .

Laser beam printer system printer device 2
2, since the laser beam printer 22 prints the image data developed on the bitmap memory as it is, as described above, the application program 10 of the client system 1 is used. Then, after the print control code indicating that the data is print data for the laser beam printer type printer device, as shown in FIG. Is, for example,
The print data is transmitted as a plurality of print data arranged in units of 4 bytes, and the data is compressed in units of 4 bytes. Specifically, as described in FIG. 4, “0” indicates “4 bytes” and “1” indicates “4 bytes”. Data compression such as “byte” and “0” is converted to “4 bytes”,... Is transmitted to the line 3 and stored in the spool 20 of the corresponding server system 2.

In the server system 2, the spool
Extracts / compresses compressed data stored in 20 2
1 (see FIG. 3), decompress it to the original print data,
After being developed on a bitmap memory having the same capacity as a photosensitive drum (not shown), the latent image is recorded on the photosensitive drum as a latent image, and the latent image is transferred to printing paper.

Accordingly, as shown in FIG. 2A, the print data for the laser beam printer type printer device 22 is, for example, data indicating a ruled line consisting of 3 bits × 4 bytes in units of 4 bytes. `` 00000000 '' `` 1111
The print data is output as print data including “1111” and “00000000”, and is compressed in units of 4 bytes as described above.

Specifically, print control data added to the head of the print data. The print control data is called an escape sequence code (ESQ code) in an operating system (OS) of a personal computer or the like. ｝, Which is control data that controls printing, screen display, etc., is analyzed by the print control code analysis unit 13 and recognized as rectangular image data for the printer device 22 of the laser beam printer system. In the corresponding rectangular image compression processing unit 120, the above data compression is performed and output to the line 3.

For the printer 22 of the serial printer system, after the print control code indicating from the application program 10 of the client system 1 that the data is print data for the printer of the serial printer system, FIG. As shown in (b), for example, the number of dots of the head of the serial printer, for example,
After the print data of 24 dots (3 bytes) × 1 bit unit is sent out and stored in the spool 20 of the corresponding server system 2, the data of 3 bytes (24 bits) of the number of dots constituting the head is transferred. The data is sent to a register (not shown) for buffering, and serial printing is performed in units of 24 dots × 1 dot.

Therefore, as shown in FIG. 2B, the print data for the laser beam printer type printer device 22 is, for example, data indicating a ruled line consisting of 24 dots × 4 bytes. Is 8 dots wide,
Since the print data indicated by 3-byte "00FF00" (the "FF" portion indicates the width of the ruled line) is to be continued for the ruled line in one line, as described above, "00FF00" Is the compressed data indicating how many times the "00FF00" continues. In the example of FIG. 2B, the compressed data indicates that "00FF00" continues for "32 bits".

As in the case of FIG. 2 (a), the print control data added to the head of the print data is analyzed by the print control code analyzing unit 13, and the printer head for the printer device 22 of the serial printer system is analyzed. The data is recognized as image data, and the corresponding printer head image compression processing unit 121 performs the data compression described above.
Output to line 3.

It should be noted that the print data includes code data such as characters in addition to the image data, and the code data is converted to the code data by a print control code designating the code data. The fact that the print control code analysis unit 13 recognizes that the code data is present causes the code data compression processing unit 123 (see FIG. 1) to perform data compression suitable for the code data.

More specifically, assuming that the character code is, for example, "8080" (hexadecimal), when two or more "80" s constituting one byte of data are continued,
Data compression such as "2" of "80" is performed. If the 1-byte data is not the same, it is sent out to the line 3 without any data compression.

As described above, in the present invention, FIG.
The print control code analysis unit 13 analyzes the rectangular image data and the printer head image data shown in (b), and recognizes that they are the rectangular image data shown in FIG. When the rectangular image compression processing unit 120 recognizes that the data is the printer head image data shown in FIG. 2B, the data is sent to the printer head image compression processing unit 121, and the characteristics of each print data are obtained. The feature is that the data is compressed efficiently.

[0038]

As described above in detail, according to the print data compression method of the present invention, the print data compression ratio can be improved on the computer system integrated by the line control mechanism.
In addition, the shortening of the compression processing time makes it possible to shorten the transfer time of the print data via the line, further reduce the spool capacity, and share the data via the line on the computer system integrated by the line control mechanism. It greatly contributes to the improvement of the performance of the printing process to the printer device.
Also, even when a new print control code (printer device) is supported, it can be easily handled by adding a new compression processing unit to the individual compression unit 12 in FIG.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a diagram schematically showing an embodiment of the present invention.

FIG. 3 is a view for explaining a conventional print data compression method (part 1);

FIG. 4 illustrates a conventional print data compression method (part 2).

[Explanation of symbols]

1 Client system 10 Application program 11 Virtual printer 12 Individual compression unit 12a Compression / transmission unit 120 Rectangular image compression processing unit 121 Printer head image compression processing unit 123 Code data compression processing unit 13 Print control code analysis unit 2 Server system 20 Spool 21 Take out / Expansion unit 22 Printing device or printer device 3 lines Print control code

Claims (1)

(57) [Claims] 1. A server system (2) to which a printing device (22) for taking in print data to which a print control code () is added and performing printing in a format designated by the print control code () is connected. A client system (1) that executes an application program (10) and requests a printing device (22) of the server system (2) to print is integrated with a client system (1) in a computer system integrated by a line control mechanism. 1) is a method for compressing image data included in print data when printing is performed on the printing device (22) of the server system (2) via the line (3), According to the data format of each printing device (22) provided in 2), in the client system (1),
A plurality of types of compression processing units (120, 121, ...) are provided to analyze the print control code () of print data output from the application program (10), and to match the data format of the printing device (22) to be output. , The compression processing unit
(120, or 121, ...) and select the printing device
A method for compressing print data, wherein the method for compressing image data is dynamically changed according to (22).