JP2000118056A - Printing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compress a quantity of transfer data without increasing a process load and achieve high-speed printing by transferring from a host apparatus to a printing apparatus intermediate data generated in a process of developing print data to bit map data, obtaining and printing the bit map data from the intermediate data. SOLUTION: Print data are processed to be developed by a printer driver 2 and transferred to a printing apparatus through a spooler 3 and a transmitting receiving part 4. In this case, character data among the print data is selected and input to a font-generating part 7 of the printer driver 2. Whether or not the character data is cached to the printing apparatus is judged by a judging part 11. When the judgment is NO and the character data is an outline, the character data is developed to edge data. If the edge data is larger than a bit map, the edge data is developed to the bit map by an edge data-developing part 14. If the edge data is smaller than the bit map, the edge data as intermediate data is output to the spooler 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a printing system for printing print data generated by a host device such as a personal computer by a printing device connected to the host device.

[0002]

2. Description of the Related Art Documents and other print data created by a personal computer or a word processor are transferred and printed by an externally connected printing device. In recent years, page printers widely used as this type of printing apparatus have been significantly multifunctional and diversified. In addition, some page printers that require lower prices do not have a built-in font for converting character codes into bitmap data. In such a page printer, font data is prepared on the host device side as a host. Simultaneously with the start of printing, the font data is downloaded to the printing device and used in the printing device. If the print data includes an outline font, the print data is rasterized by the host device, developed into bitmap data, and then transferred to the printing device.

However, using such a method,
The amount of data transferred from the host device to the printing device becomes large. In this case, there is a problem that the data transfer time increases and the total printing speed decreases. In order to solve such a problem, for example, Japanese Patent Application Laid-Open No. Hei 7-146691 introduces a technique using a cache memory.

That is, in the cache memory on the printer side,
Bitmap data corresponding to frequently used character codes is stored. The character code is transferred from the host device, and converted into bitmap data by referring to the cache memory on the printing device side. According to this method, for print data using the same character a plurality of times, the corresponding bitmap data is transferred from the host device to the printing device only once,
From the second time onward, only the character code may be transferred. Therefore, the amount of transfer data can be greatly reduced.

[0005]

However, the above-mentioned prior art has the following problems to be solved.
When a cache memory is used, the effect greatly depends on the contents of the print data. For example, the effect of using a cache memory in a Japanese document is considerably lower than that in an English document. This is because the frequency of using the same character code is low. Further, in order to sufficiently increase the effect of using the cache memory, the storage capacity of the cache memory must be increased. However,
This cannot reduce the price of the printing apparatus, which is the original purpose.

[0006]

The present invention employs the following structure to solve the above problems. <Structure 1> Consisting of a host device and a printing device, the host device transfers intermediate data generated in the process of expanding print data into bitmap data to the printing device, and the printing device A printing system, wherein the printing is performed by obtaining the bitmap data from data.

<Structure 2> In the printing system according to Structure 1, the upper device compares the bitmap data with the intermediate data, and transfers the smaller data size to the printer. Printing system.

<Structure 3> In the printing system according to Structure 1, the printing apparatus compares the bitmap data with the intermediate data and stores the smaller data size in the cache memory. Printing system.

<Structure 4> In the printing system described in Structure 3, the host device sends a command for distinguishing between one unit of bitmap data and one unit of intermediate data to be transferred to the printing device, by using bitmap data or intermediate data. And a cache hit command is transferred to the printing apparatus when a cache hit occurs.

<Structure 5> In the printing system according to any one of Structures 1 to 4, the intermediate data may include edge data obtained by extracting a change point of bitmap data obtained from an outline font. Characteristic printing system.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below using specific examples. <Specific Example> FIG. 1 is a block diagram of a host device of a printing system according to the present invention. In the present invention, with this higher-level device,
First, intermediate data generated in the process of developing bitmap data from print data is obtained. The intermediate data is, for example, edge data described later. And
For example, if the edge data for one character has a smaller data size than the bitmap data for one character, the edge data is transferred to the printing apparatus. In the opposite case, the bitmap data is transferred to the printing device. The printing device that has received the edge data develops the data into bitmap data and performs printing. In this way, the amount of data transferred from the host device to the printing device is compressed. Hereinafter, the configuration of the printing system will be sequentially described with reference to the drawings.

FIG. 1 is a block diagram of a main part of a host device such as a personal computer. The print data is generated by the application program 1. This is developed by the printer driver 2 and transferred to a printing device (not shown) through the spooler 3 and the transmission / reception unit 4. The printer driver 2 includes a print data selection unit 5, an image / graphic data processing unit 6, a font generation unit 7, a font storage unit 8, and a cache registration information storage unit 9.

The font generating section 7 includes a cache determining section 11, an outline determining section 12, a font size determining section 13, an edge data expanding section 14, and an edge data generating section 15. The print data selection unit 5 is a part that analyzes the contents of the print data passed from the application program 1, selects processing to be performed in accordance with the contents, and distributes the processed data to a subsequent circuit. The print data includes character data, image data, and graphic data.

The present invention is particularly effective when handling fonts of character data. Accordingly, the print data selection unit 5 functions to selectively output character data to the font generation unit 7 and to send image data and graphic data to the spooler 3 through the image / graphic data processing unit 6. The character data is data including font information, character code information, print position information of the character, and the like. Font information is information indicating the type, size, and modification of characters.

Image / graphic data processing unit 6
Is a part having a function of receiving image data and graphic data and transferring the data to the spooler 3. The spooler 3 is composed of a file for storing data to be transferred to the printing device. Generally, the spooler 3 is generated as a temporary file in a hard disk of a computer as a host device. The transmission / reception unit 4 is an interface connecting the host device and the printing device, and is configured by a Centronics cable or the like.

The font storage unit 8 is a memory that stores font data corresponding to character codes. Since font data is a type of bitmap data, the font data will be referred to as bitmap data and will be described below.

The cache registration information storage section 9 is a section for registering and storing information indicating character data registered in a cache memory of the printing apparatus before or during printing. The cache determination unit 11 refers to the cache registration information storage unit 9 and determines whether the character data input from the print data selection unit 5 is registered in the printing apparatus as a cache. If it is determined that the character data is registered in the cache, the command is added to the character data indicating that the character is registered in the cache, and the character data is output to the spooler 3.

On the other hand, when the character data is not registered in the cache, the character data is output to the outline determination unit 12 in order to develop the character data into bitmap data. The outline determination unit 12 is a unit that extracts character code information from the received character data, refers to the font storage unit 8, extracts corresponding bitmap data, and transfers the extracted bitmap data to the spooler 3. This process is performed when the input character data is a bitmap font.

On the other hand, if the input character data is an outline font, the data is output to the edge data generator 15. This specific example is characterized in that the data amount is reduced particularly when the outline font bitmap data is transferred.

The edge data generation section 15 extracts outline information from the font storage section 8 and generates edge data in a manner described later. That is, edge data is once generated as intermediate data during processing for expanding character data into bitmap data. Most of the edge data has a feature that the data size is smaller than the bitmap data finally obtained.

Therefore, in the present invention, the edge data is transferred to the printing apparatus, and the printing apparatus performs control such that the edge data is developed into bitmap data. In addition,
The data size of all edge data is not necessarily smaller than the corresponding bitmap data. Therefore, a font size determination unit 13 is provided. The font size determination unit 13 is a unit that determines whether a font is smaller than a predetermined size and performs a certain process.

Generally, when the font is smaller than a predetermined size, the data amount of the bitmap data is smaller than that of the edge data. Therefore, when the edge data is smaller, the edge data is transferred to the spooler 3 and
Send it to the printing device as it is. On the other hand, when the size of the bitmap data is smaller, the edge data is transferred to the edge data developing unit 14 and a request for developing the bitmap data is made. The edge data developing unit 14 is a part that expands the input edge data to generate bitmap data. The generated bitmap data is stored in spooler 3
Is stored in

FIG. 2 shows a block diagram of the printing apparatus. The printing apparatus includes a transmission / reception unit 21 and a print data selection unit 2
2. Image / graphic data processing unit 23, cache registration information storage unit 24, cache data storage unit 2.
5, cache determining unit 26, cache data reading unit 27, cache data writing unit 28, cache data holding unit 29, bitmap edge data determining unit 3.
0, an edge data developing unit 31, an image memory 32, and a printer engine 33.

The transmission / reception unit 21 is an interface connected to the host device shown in FIG. 1 for transmitting and receiving print data. The print data selection unit 22 has a function of determining the type of processing of the print data received by the transmission / reception unit 21, selecting the type of processing, and sending the selected data to a subsequent circuit. That is, the image data and the graphic data are transferred to the image / graphic data processing unit 23, and the print data is transferred to the cache determination unit 26.
Transfer to Image / graphic data processing unit 23
Is a part for performing processing for storing input data in the image memory 32.

The cache determining unit 26 determines whether the input character data is registered in the cache in the printing apparatus. Cache registration information storage unit 2
Reference numeral 4 denotes a portion storing information indicating character data registered in the cache. Cache data storage unit 25
Is a part for storing character data to be registered in the cache.

When the cache determining unit 26 determines that the character data is registered in the cache in the printing apparatus with reference to the cache registration information storage unit 24, the cache determining unit 26 transfers the character data to the cache data reading unit 27. If it is determined that the data is not registered in the cache, the character data is stored in the cache data holding unit 29, and the edge data or the bitmap data is output to the cache data writing unit 28.

The cache data writing unit 28 stores the edge data or bitmap data to be registered in the cache in the cache data storage unit 25. That is, the cache data storage unit 25 does not necessarily store all the bitmap data of the character data registered in the cache. If the edge data has a smaller data size, the edge data is stored. Has functions. This is to enable registration of a large amount of cache even if a little.

The cache data reading unit 27 stores the bitmap data or edge data read from the cache data storage unit 25 in the cache data holding unit 2.
9 is provided. The cache determination unit 26 has a function of transferring bitmap data or edge data received via the print data selection unit 22 to the cache data holding unit 29. The bitmap edge data determination unit 30 is a unit that determines whether data input from the cache data holding unit 29 is bitmap data or edge data.

If it is determined that the data is bitmap data, the data is transferred to the image memory 32. If it is determined that the data is edge data, the data is transferred to the edge data developing unit 31. The edge data developing unit 31 develops the edge data into bitmap data and
It has a function to store in. Thus, the edge data stored in the cache data storage unit 25 is developed into bitmap data and used for printing. Image memory 32
Is a memory for storing one page of print image data. The printer engine 33 performs printing based on the data stored in the image memory 32. The mechanism and function of this printer engine are not different from those of the conventional apparatus.

Next, the specific contents of the edge data will be described. FIG. 3 is an explanatory diagram of the edge data. In this figure, thin lines indicate grids that separate the pixels, and thick lines indicate outlines. In the outline data, it is assumed that a path for scaling the coordinate values has already been constructed, correction has been performed by hint processing for quality assurance, and curve smoothing for approximating the curve portion with a sufficiently fine straight line has been completed. I do.

For example, a method called scan conversion is used to fill the outline 35 as shown in FIG. In scan conversion, a line segment passing through the center of each grid is set in advance. This line segment is shown by a horizontal broken line in FIG. The intersection between the line segment formed by the broken line and the outline 35 is obtained. This intersection is referred to as an edge 36. Next, the edge 36 is converted into an integer. That is, when the edge 36 is not on the grid,
Transfer to the nearest grid (FIG. 3 (c)).

Thereafter, the number of edges 36 is counted in order from the left along the dashed scan line shown in FIG. Then, the space between the odd-numbered edge 36 and the even-numbered edge 36 is filled. Thus, as shown in FIG. 3D, the filling 37 of the character portion is completed. Here, attention is paid to the edge 36 shown in FIG. Edge data can be generated by combining the position of the odd-numbered edge with the length of the pixel filled between the odd-numbered edge and the even-numbered edge for each scan line indicated by the broken line.

FIG. 4 is an explanatory diagram of edge data. FIG. 4A shows an example of bitmap data, in which a portion written as “0” is a white dot and a portion written as “1” is a black dot. This bitmap data is, for example, the top line of the bitmap data after filling shown in FIG. Here, as shown in FIG. 4B, edge data is generated.

That is, the odd-numbered edge of the bitmap data shown in FIG. 4A is the seventh edge from the left (counting starts from the zeroth). In addition, the number of pixels to be painted starting from the edge is “3”. Further, the pixels after the filling are all “0”. In this case,
The edge data can be represented as “7, 3, CR”.

The edge data has a format similar to the run length method widely used in image compression and the like. Therefore, in this example, the data size of the edge data shown in (b) is more compressed than the bitmap data shown in (a).

FIG. 5 is an explanatory diagram showing a data size comparison between such bitmap data and edge data. The vertical axis of the figure represents the data size in bytes, and the horizontal axis represents the character size in dots. The solid line in the graph indicates the amount of bitmap data, and the broken line indicates the amount of edge data.

As shown in FIG.
If the size is equal to or larger than the dot, the data size of the edge data is smaller than that of the bitmap data. 60 dots corresponds to a character size of 7.2 points when the resolution of the printer is 600 dpi (dots / inch). That is, if the font size is 7.2 points or less, the data size is smaller when the bitmap data is transferred to the printing apparatus, so this is adopted.

Conversely, if the font size exceeds 7.2 points, the edge data is transferred to the print data. In this case, in order to distinguish whether edge data or bitmap data has been transferred, each time edge data for one character is transferred, a command indicating that the character is edge data is added to the character. . Each time bitmap data for one character is transferred, a command indicating that the data is bitmap data is added to the bitmap data.

Further, as will be described later, if the data is cache-registered on the printing apparatus side, a command to that effect and character data are transferred to the print data. This is for causing the printing apparatus to develop the data into bitmap data using a cache. Font generator 7 shown in FIG.
Performs such processing.

Hereinafter, a specific operation of the apparatus shown in FIGS. 1 and 2 will be described with reference to flowcharts. FIG. 6 is an operation flowchart of the host device. This mainly shows the operation of the font generator 7 in FIG. Character data is selected and input from the print data requested by the application program 1 to be printed to the font generator 7. The cache determination unit 11 determines whether the input character data is cached in the printing device (Step S1). If cached, a cache hit command is generated, added to the character data, and written to the spooler 3 (step S10). Then, the process jumps to step S9.

On the other hand, if it is not cached, the process proceeds to step S2, where the outline determination unit 12
Determine whether the character data is an outline. If it is an outline, the process proceeds to step S3, where the edge data generation unit 15 expands the data to edge data. Then, in step S4, the font size determination unit 13 determines whether or not the edge data is larger than the bitmap. If the edge data is larger than the bitmap, the process proceeds to step S5, and the edge data development unit 14 expands to the bitmap.

On the other hand, if it is determined that the edge data is smaller than the bitmap, the edge data as intermediate data is output to the spooler 3. In step S2,
If the specified font is not an outline, the process jumps from step S2 to step S6. Step S6
Then, it is determined whether or not the character specified by the character data is a cache candidate. Information indicating the presence or absence of such cache registration is exchanged with the printing apparatus via the transmission / reception unit 4 through bidirectional communication.

The cache registration information storage unit 9 stores information on characters to be registered in the cache created according to past printing frequencies and user designations. With reference to this, in the case of a cache candidate, the process proceeds to step S7, where the cache information is added to the output data. As a result, the character data is cache-registered in the cache memory of the printing apparatus. In step S8, the cache registration information inside the cache registration information storage unit 9 is updated. Then, in step S9, data is output from the spooler 3 through the transmission / reception unit 4.

FIG. 7 is a flowchart showing the operation of the printing apparatus. The printing apparatus shown in FIG. 2 operates as shown in FIG.
First, in step S1, the transmission / reception unit 21 receives print data, the print data selection unit 22 selects print data, and analyzes a command. In this example, especially for an outline font, character data such as a command and bitmap data, a command and edge data, or a command including cache registration information is input. This is analyzed and if it is a character drawing command, the process proceeds to step S2.

If it is any other command, the flow advances to step S9 to process each command. If the command is a data end command, the flow advances to step S10 to start the print engine, transfer the image data from the image memory 32, and execute printing.

In step S2, first, the cache determination unit 26 determines whether the character is a cached character. If it is a cached character, the flow advances to step S3 to transfer the character data to the cache data reading unit 27, and access the cache data storage unit 25, which is a cache memory.

In step S4, it is determined whether the character is a bitmap. This is performed by identifying the added command. If it is not a bitmap, the process proceeds to step S5, and the edge data is developed into bitmap data. If it is bitmap data, the process proceeds from step S4 to step S6, and this is stored in the image memory 32.

Further, in step S7, it is determined whether or not the command is a cache candidate based on the contents of the command transferred from the higher-level device. If it is a cache candidate, the process proceeds to step S8, in which the cache data writing unit 28 is driven to execute cache registration. That is, when image data or graphic data is transferred from a higher-level device, the image data or graphic data is directly stored in the image memory 32. When bitmap data is transferred for small-size characters, this is stored in the image memory 32 as it is. I do. The same procedure is performed for a bitmap font that is not an outline font.

On the other hand, in the case of outline fonts and large-size characters, edge data is transferred. This is developed by the edge data developing unit 31 and stored in the image memory 32. Further, in the case of the outline font, if the bitmap data or the edge data is a cache candidate, the cache data storage unit 2
5 to use. That is, if edge data having a small data size is transferred from the host device to the printing device, the printing speed is improved for each character.

Conventionally, the cache data storage unit 2
5, bitmap data or edge data having the smaller size is stored and registered in the present invention, so that the cache data storage unit 25 is effectively used and more data is stored. Cache data can be stored.

The present invention is not limited to the above embodiment. In the above example, the edge data generated intermediately when the outline font is expanded into bitmap data is
The transfer data is used in order to speed up data transfer by using the functions of the conventional apparatus without changing the conventional processing.

Therefore, if the intermediate data is another intermediate data generated when the print data is developed into bitmap data and the data size can be reduced as compared with the bitmap data, this is used. It can be adopted as transfer data. This can be used as cache data.

[0053]

According to the printing system of the present invention described above, intermediate data generated when the print data is expanded into bitmap data is transferred from the host device to the printing device, and the transfer data amount is compressed and transferred. Speed can be increased. In addition, if data generated in an intermediate step is used at the time of bitmap data expansion, such as edge data, the amount of transfer data can be compressed and the load reduced without increasing the processing load. Can be. For this reason, high-speed printing becomes possible as a whole.

Further, since such edge data and bitmap data are compared and the smaller data size is used for data transfer and cache, it is possible to improve the use efficiency of the cache. Further, even in a printing apparatus in which a cache cannot always be mounted, an effective printing speed can be improved by the present invention.

[Brief description of the drawings]

FIG. 1 is a block diagram of a host device.

FIG. 2 is a block diagram of a printing apparatus.

FIG. 3 is an explanatory diagram (part 1) of edge data.

FIG. 4 is an explanatory diagram (part 2) of edge data.

FIG. 5 is an explanatory diagram of data size comparison.

FIG. 6 is an operation flowchart of a host device.

FIG. 7 is an operation flowchart of the printing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Application program 2 Printer driver 3 Spooler 4 Transmission / reception part 5 Print data selection part 6 Image / graphic data processing part 7 Font generation part 8 Font storage part 9 Cache registration information storage part

Claims (5)

[Claims] An upper device and a printing device, wherein the upper device transfers intermediate data generated in a process of expanding print data into bitmap data to the printing device; A printing system wherein the bitmap data is obtained from intermediate data and printing is performed. 2. The printing system according to claim 1, wherein the higher-level device compares the bitmap data with the intermediate data, and transfers a smaller data size to a printer. Printing system. 3. The printing system according to claim 1, wherein the printing device compares the bitmap data with the intermediate data, and stores a smaller data size in a cache memory. system. 4. The printing system according to claim 3, wherein the host device transmits a command for distinguishing one unit of bitmap data and one unit of intermediate data to be transferred to the printing device.
A printing system which transfers a cache hit command to a printing apparatus when the cache hit occurs together with the bitmap data or the intermediate data and the cache hit. 5. The printing system according to claim 1, wherein the intermediate data comprises edge data obtained by extracting a change point of bitmap data obtained from an outline font. And printing system.