JPH11203070A - Printer controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce required RAM capacity, to reduce the cost, to speed up the developing/transferring of picture data and to shorten the time required for printing. SOLUTION: At the time of image-developing picture data sent from a host computer 1 on RAM 4, it is divided into plural bands in an auxiliary scanning direction and they are developed. At the time of reading picture data which is image-developed from RAM 4 by a video DMA controller 6 and sending it to a printer engine 3, a video DMA operation is not executed, white data is automatically generated and is outputted to the printer engine 3 in the case of a white band where the picture to be printed does not exist.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer control device (generally referred to as a "printer controller") that develops image data created on a host computer, sends the image data to a printer engine such as a laser beam printer, and executes printing. ).

[0002]

2. Description of the Related Art Generally, when an image is developed by a printer controller, an area to be printed is divided into bands. In a conventional printer controller, a page to be printed is divided into bands in the sub-scanning direction, an image is developed on an arbitrary RAM address, and processing is performed using a partial bitmap method.
No. 96794 discloses one. Japanese Patent Application Laid-Open No. Hei 8-258378 discloses a system in which an image to be printed is drawn and developed by dividing it into bands, and blank data is generated and output for blank spaces. Therefore, these techniques will be described.

A user creates an image to be printed by a host computer, designates a printer for printing, and issues a print command for the created image. When a print command is issued,
The host computer converts the image data into a system of instruction codes that can be interpreted by the printer controller using printer driver software for the connected printer, and sends the converted image data to the interface of the connected printer. Output.

In the printer controller, when reception of image data to be printed is started by the host interface, a CPU of the printer controller draws the transmitted image data on a RAM and develops the image data. As a method of drawing and developing image data by a printer controller, there are a full bitmap method in which a print image of one page is stored as it is and a partial bitmap method in which a print image is divided into bands and stored.

For example, when storing an image as shown in FIG. 8 in a RAM, in the case of the full bit map system, as shown in an address map of FIG. Is stored as it is. However, the actual address map is 1
The code data is byte by byte, and the image data is arranged serially from the head address of the image.

In the case of the partial bitmap system, an image to be printed is divided into bands having the same width in the sub-scanning direction as shown in FIG. 10 (in this example, the bands are divided into eight bands, but the number of bands is arbitrary. Good), as shown in FIG. 11, for each band, an image is drawn by allocating a vacant area in the work RAM that can accommodate the band.

As described above, by using the partial bitmap method, even if it is not always possible to secure a continuous free area of one page on the work RAM, the image can be developed. Next, after the CPU develops the image on the RAM, the CPU issues a print start command to the printer engine to start printing, and outputs the developed image data to the printer engine to execute printing.

However, when image data is output to a printer engine (video output), a huge amount of data must be transferred in a short period of time.
DMA processing is performed by the MA controller to increase the speed. In the case of the partial bitmap system, a DMA start address and the number of transfers of a band to be printed are designated to the video DMA controller, and the DMA operation for the set number of transfers is performed.

Further, the video DMA controller has a D
When the MA transfer is completed, an interrupt for ending the video DMA is issued to the CPU to notify the end. Then the CPU
The DMA parameters of the following band are changed to the video DMA again.
The output of the image data to the printer engine is completed by setting the controller to the controller and repeating the same video DMA operation by the video DMA controller.

Further, when the image development of the image data is completed, a portion where the image to be printed finally appears with the developed image data is searched. In the example shown in FIG. 10, it is determined that the image of band 6 is the last data.
And since all the areas after that are blank (white),
By forcibly outputting white data to the printer engine or issuing a blank area drawing command without performing the video DMA operation, the CPU can develop the image of the image data of the next page. , To improve the efficiency and speed of processing.

When printing is completed without an error such as a paper jam occurring in the printer engine, C
The PU can reuse the RAM area of the developed image by rewriting all the RAM area to white data and clearing the RAM, for the next and subsequent processes. By performing such processing and operation, it becomes possible to print the image data created by the user by dividing the image data into bands, and it is possible to print without performing the video DMA of the blank portion at the rear end of the image. Become.

[0012]

With the development of laser printer engines in recent years, the number of machines that handle high-speed and high-resolution images has increased, and color laser printers have also been developed. R
AM is needed. Accordingly, it has become necessary to configure a printer controller with less RAM using a compression technique.

However, in the above-described conventional partial bitmap printer controller, the main purpose is to improve the efficiency of image development of the print image of the next page and to minimize the print underrun during printing. Therefore, it is detected where the last image data of the image data of one page to be printed is, and only the print portion after the detected position is set as a blank area, and the video DM is determined.
By forcibly outputting the white data without performing the A operation, the traffic on the bus to which the RAM is connected is reduced, thereby speeding up the reception of the next page of image data and the development of the image.

Therefore, when a blank band exists before the last image data, a video DMA operation for outputting a white image must be performed even for the blank area, which is wasteful. There is a problem that a long processing time is spent. Even if a blank band exists before the last image data, it is necessary to secure a storage area (memory capacity) of the RAM necessary to store the image image of the blank portion. There was also a problem that the cost had to be increased due to the necessity.

Further, a RAM for storing the blank portion
The memory clear processing for printing the next page must be performed on the area, and there is a problem that the memory clear processing speed is reduced.

In a normal printer controller,
In general, image data obtained by expanding the image is compressed and stored, and when the image data is output to the printer engine by the video DMA operation, the image data is generally expanded and output. Nevertheless, it is necessary to read out the compressed image data from the RAM and output it after performing the decompression processing, which not only results in poor compression efficiency but also increases the traffic volume of the bus to which the RAM is connected. There is also a problem that the processing speed is further reduced.

Furthermore, even in the case of a method in which image transfer is performed when an image is transferred from the host computer to the printer controller, blank image data must be transferred, and the image transfer amount increases. In addition to lowering the processing speed, there is also a problem that the traffic volume of the entire network is increased when operating in a network environment.

According to the present invention, in a partial bitmap type printer control device, the above-described disadvantages are solved, the storage area of the RAM is more efficiently used, and the required RAM capacity is reduced to reduce the required amount. It is an object of the present invention to increase the cost and speed up the process of developing and transferring image data to shorten the time required for printing.

[0019]

SUMMARY OF THE INVENTION The present invention is directed to a printer control apparatus for expanding image data created on a host computer, sending the image data to a printer engine, and executing printing. Are provided.

More specifically, a developing processing means for dividing the image data into a plurality of bands in the sub-scanning direction in the printer engine and developing the image on the RAM, and a method for outputting the developed image data to the printer engine. A video DMA controller for directly accessing the RAM and outputting the data at high speed; determining means for determining whether or not the image data developed in the RAM is blank for each band; Is used by the video DMA controller
Blank data output means for generating and outputting white data without reading M image data.

With this configuration, even at the time of outputting image data of an intermediate white band, bus traffic can be reduced and processing can be speeded up.
Further, when printing a plurality of continuous pages, the rasterization processing unit outputs the next page even if the video DMA controller is outputting white data for the band determined to be blank by the determination unit. Providing means for developing the image of the print data makes it possible to speed up the image developing process of the image data.

Alternatively, in place of the expansion processing means, the image data is divided into a plurality of bands in the sub-scanning direction in the printer engine and the image is expanded on the RAM, and the RAM is allocated only to the band requiring the expansion processing. When the image data expanded by the expansion processing means is output to the printer engine, the video DMA controller directly accesses the RAM and outputs the image data at a high speed. For the bands not performed, white data may be generated and output.

With this configuration, when developing the image data in the RAM, the RAM area can be allocated only to the band where the image data to be printed exists, and it is necessary to store the redundant white image in the RAM. Is eliminated, so that the storage capacity of the RAM can be reduced, so that the cost can be reduced.

In each of the above-described printer control devices, it is preferable that the expansion processing means has means for arbitrarily setting the width of a band in which image data is expanded. This allows you to set a bandwidth that matches the width of the white image.
For example, when printing text data over a plurality of lines, the white space can be designated as the line spacing, and the RAM can be used efficiently.

Further, the expansion processing means performs the RA processing only when allocating the RAM to the band requiring the expansion processing.
It is preferable to have means for performing a RAM clearing process of writing white data in the area assigned by M. That is, since the printer control device according to the present invention can automatically output white data when printing a white band, it does not perform the memory clear processing that is normally performed after printing is completed, and the image data is not processed when the image is developed. By performing the memory clear processing of the band area when it is detected that the band exists, it is not necessary to perform the memory clear processing of the unnecessary area, and the processing can be speeded up.

Further, the expansion processing means compresses the image data expanded on the RAM into a plurality of bands and stores the compressed image data in the RAM. The expanded image image is expanded and transmitted to the video DMA controller. In addition to the output, when the video DMA controller is generating and outputting white data, it is preferable to provide an expansion means for performing expansion processing of a compressed image image of the next band in advance. By doing so, RA
The storage area of M can be used more efficiently. In this case, it is desirable to provide a memory (band buffer) for temporarily storing the image data expanded by the expansion means.

Further, when the decompression means performs the decompression processing in advance, there is provided means for receiving the image data from the host computer and performing the image decompression and compression processing of the image data by the decompression processing means with priority. Good. As a result, the priority of the bus arbitration is lowered and the bus is free, as in the case where the image development of the image data of the next page and subsequent pages is not performed, and the image data of the next page and subsequent pages is not received from the host computer. The image data compressed during the period can be expanded, and the processing can be made more efficient and faster.

Further, image data created on the host computer, divided into a plurality of bands in the sub-scanning direction by the printer engine by the printer driver, converted into a code system that can be interpreted by the printer control device, and developed is transmitted. The above-described object can also be achieved by providing the following units in a printer control device that sends the data to a printer engine to execute printing.

That is, a developing processing means for dividing the image data which has been converted into the code system and transmitted and dividing the image data into a plurality of bands and developing the image on a RAM, and a RAM for outputting the developed image data to a printer engine. And a video DMA controller for directly accessing the video DM and outputting a high-speed output.
Blank data output means for generating and outputting white data without causing the A controller to read image data from the RAM is provided.

In any of these printer control devices, if the expansion processing means is processing means for developing image data for printing by superimposing a plurality of colors, the image processing is performed for each color to be printed. It is desirable to have means for individually managing bands for developing data into images. As a result, the frequency of occurrence of white bands can be increased, so that an inexpensive color printer control device with a reduced ROM memory capacity can be provided.

[0031]

Embodiments of the present invention will be specifically described below with reference to the drawings. First, the first of the present invention
An embodiment will be described. FIG. 5 is a block diagram of a printer system using a printer controller as a printer control device according to the first embodiment of the present invention.

This printer system comprises a host computer 1, a printer controller 2, a printer engine 3
The printer controller 2 and the printer engine 3 are integrated to constitute a printer.

The printer controller 2 includes a host interface (hereinafter abbreviated as “host I / F”) 12,
The CPU 13, which is a central processing unit, the ROM 10, which is a program memory, and the RAM 4, which is a data memory, are mutually connected by a system bus 5 to constitute a microcomputer.

Further, a video DMA controller (hereinafter abbreviated as "VDMAC") 6 connected to the system bus, a decompressor 9, a selector 7, and an engine interface (abbreviated as "engine I / F") 8 And Then, the host computer 1 is connected to the host I / F 12, and the printer engine 3 is connected to the engine I / F 8.

In this printer system, a user uses the application software on the host computer 1 to create image data to be printed. At this time, the image data created by the user
There are various types of image data, such as those that span multiple pages and those that are created as color data. And
When the creation of the image data is completed, the user selects a printer to be printed from the printers connected to the host computer 1 and capable of printing, and issues a print command.

At this time, the print command from the user includes designation of the number of copies, designation of color or monochrome, designation of enlargement or reduction ratio, designation of paper size, and a plurality of pages on one sheet. Various print modes are designated, such as designation of whether or not to perform aggregate printing for printing.

When a print command is issued by the user, the connected printer is controlled by software called a printer driver stored inside the host computer 1 so as to satisfy various modes specified by the user. The code is converted into a code that can be decoded by the controller 2, and the code of the converted image data is output to the printer controller 2.

The printer controller 2 has a host I / F 12 composed of a network and various interfaces.
When the reception of image data from the host computer 1 starts, an interrupt is generated to notify the CPU 13 that a print command has been issued, and the received image data is buffered in the RAM 4 and temporarily stored. .

The CPU 13 develops an image in the RAM 4 in order to convert the received and buffered image data into data that can be printed by the printer engine 3.
The image received as the code information is converted into bitmap information and stored. At this time, the CPU 13
The image development portion of M4 is virtually divided into bands in the sub-scanning direction to develop the image, and a table as shown in FIG. 2 for referencing whether or not there is image data to be printed in each band. It is created in an area in the RAM 4 different from the area where the image is developed.

Further, when dividing into bands, it is not necessary to secure a frame memory for one page in advance, and only bands that need to be developed are sequentially allocated to the RAM 4 and developed, so that the memory area can be efficiently used. Can be used Further, by performing the memory clear only when allocating the band, it is not necessary to perform the multiple memory clear processing, and thus more efficient processing can be performed.

In the case of a color printer controller,
Normally, in order to develop four colors of CMYK, for example, if the color to be developed is red, only M (magenta) and Y (yellow) need to be developed. Therefore, the processing is performed by dividing each color into bands. This eliminates the need to secure a redundant RAM area.

Simultaneously with the image development in the RAM 4,
If necessary, the image data stored in the RAM 4 can be compressed (high-efficiency encoding) and stored again in the RAM 4. A known technique may be used for the technique of compressing image data, and a description thereof will be omitted.

However, the printer controller 2 need not always be able to perform compression. Further, even in an environment where compression is possible, when the capacity of the RAM 4 is large enough to store the image data, the image data may be stored as it is without performing compression. The processing speed is increased by the amount not performed. Further, when performing compression, there are a case where the compression is performed using a dedicated compressor and a case where the compression is performed by the CPU 13.

When all the image expansion (compression) of one page of the image data received by the CPU 13 is completed, the CPU 13 sets various parameters to make the VDMAC 6 perform the video DMA, and sets the video DM.
Command the start of A. As parameters to be set, the result of referring to the table shown in FIG. 2 for the band to be printed indicates whether white band (no data) or image data exists (data exists), image data RAM that performs DMA operation when
4 specifies the start address, the number of transfers for DMA transfer, and whether or not image data for video DMA is compressed.

As described above, by adopting a configuration in which the number of transfers can be arbitrarily changed, an arbitrary bandwidth can be designated, white bands (no data) can be created as much as possible, and memory can be created. Not only can be used more efficiently, but also can be processed at a higher speed.

In the VDMAC 6, when each parameter is specified and the DMA is started, the specified address of the RAM 4 is read, and in the case of uncompressed image data, the selector 7 is set so that the input from the VDMAC 6 is valid. Then, the image data is output to the printer engine 3 through the engine I / F 8.

When the designated image data in the RAM 4 is compressed, the image data is sent to the decompressor 9 and the image data decompressed by the decompressor 9 is output to the engine I / F 8. The selector 7 is switched to output the image data from the engine I / F 8 to the printer engine 3.

When the image data is sent from the VDMAC 6, the decompressor 9 decompresses and outputs the image data using the reverse method of the compression method. In general, image data output by the printer engine 3 must be handled as image data, and a large amount of data must be transferred in a short time. If the decompression process is performed by the CPU 3, a print overrun occurs. Therefore, when performing video DMA, a dedicated decompressor is used.

When the mode specified by the CPU 13 is a white band, the VDMAC 6 forcibly generates a white image and outputs it to the selector 7. In this case, the image data is not read out from the RAM 4 but a white image corresponding to the set number of transfers is output. In general, “0” is output for “white” when there is no image data when printing in color CMYK or monochrome. However, "1" may be output according to the rules on the interface.

The expanded data and the output data from the VDMAC 6 are temporarily buffered and stored so that the image data is input from the host I / F 12 when outputting the white band. The decompression process can be performed during a time when the bus is free while it is not being used. For this purpose, it is preferable to provide a buffer memory such as a FIFO memory.

The engine I / F 8 outputs image data in accordance with the resolution and speed at which printing can be performed by the printer engine 3. The printer engine 3 executes printing of the transmitted bitmap data and completes printing.

By performing the above operation for all the bands in one page, printing of the image for one page is completed. However, when printing is performed over a plurality of pages, the image development of the previous page is completed and the video DM
At the same time as performing the printing process in the A operation, a parallel process for developing the image of the next page using the time when the bus is free is performed. In this way, the process is completed when printing of all pages is completed.

When the emulation that can be decoded by the printer controller 2 is transferred directly from the printer driver software into bands as in the case of the GDI printer system, for example, when the transfer is performed by the printer driver, Specify a blank band.

The ROM 10 stores program codes for operating the CPU 13, font information used for image development of text images, and the like.
The functions of the expansion processing means (including RAM allocation means, bandwidth setting means, RAM clear processing means, compression means, etc.), discrimination means, and blank data output means in the present invention are implemented by CPU 13 written in ROM 10. It is realized by operating according to a program.

Next, a second embodiment of the present invention will be described. FIG. 3 is a block diagram of a color printer system using a printer controller as a printer control device according to a second embodiment of the present invention. The printer controller 2 'of the second embodiment is a color printer controller, and a host computer 1 and a printer engine 3 constitute a color printer system.

In this printer controller 2 ',
The main difference from the printer controller 2 shown in FIG. 1 is that a band buffer 11 is provided instead of the selector 7. The band buffer 11 is a buffer memory for temporarily storing image data previously expanded by the expander 9 and image data read from the RAM 4 by the VDMAC 6.

Image data created on the host computer 1 by the user is sent from the host computer 1 to the host I / F 12 inside the printer controller 2 '. At this time, the host computer 1 converts the image data into a language format that can be interpreted by a connected printer controller by a printer driver and outputs the converted image data. When outputting image data, as shown in FIG. 10, the image of one page is output while being divided into a plurality of bands in the sub-scanning direction of the printer engine 3.

At this time, a band having no image data in the band area, such as band 2 in FIG. 10, is designated as a blank band to the printer controller. When one character extends over a plurality of bands as in bands 3 and 4, the character C is decomposed into two and developed. When the image data is color, the image handled by the host computer 1 is usually represented by RBG, but when printing, it is represented by CMYK, so it is divided into CMYK color components and further divided into bands. Perform processing separately.

However, the conversion from RBG to CMYK does not necessarily have to be performed by the printer driver. RBG data may be transferred and converted into CMYK data by the printer controller 2 '.

Next, with reference to the flowchart of FIG. 6, the processing relating to image development on the printer controller 2 'side will be described. In step S1, the image data received by the host I / F 12 is temporarily stored in the RAM 4. Simultaneously with the reception, an interrupt is generated in the CPU 13 to notify the reception, and the CPU 13 starts developing the image. At the time of image development, since the image data is input in advance from the printer driver in band units, the image development is performed from band 0.

Assuming that the input image data is divided into bands as shown in FIG. 10, step S2
Since the image data from the printer driver in band 0 includes the image data to be printed in the check of the above, in step S3, a RAM space having a capacity enough for one band is allocated in step S3, and allocated in step S4. The RAM of the space is cleared (0 is written). At this time, R
Any address may be assigned to the AM space as long as one band is continuous.

Next, in step S5, a band table as shown in FIG. 4 is issued in order to store that "there is data in the band 0 and a band has been allocated".
For each band number, the presence / absence of data and the start address and end address when there is data are stored. Then, the image data received in step S6 is image-developed, and compressed in step S7 to be written in the RAM area.

When all the image data of band 0 has been developed, since the next band 1 also has image data, a RAM space is allocated in the same manner, the RAM space is cleared and the image is developed, and the band table is developed. Register with. Next, since there is no image data to be printed in the band 2 area, the RAM space is not allocated and registered as a blank band (no data) only in the band table in step S10.

This operation is repeated until the last band is reached in step S8, that is, until the last band image data has been developed, and image development is performed for all the bands for one page. Then, when the development has been completed for all the pages, the determination in step S9 becomes "No next page", and the processing is terminated.

As shown in FIG. 5, a general text document is described over a plurality of lines, and the lines are spaced at a constant pitch. Therefore, by setting the bandwidth so that the blank portion corresponding to the space between lines becomes one band, it is not necessary to store the blank portion as image data in the RAM.

Further, when printing in color, CMY
Bandwidth is separately managed for each color of K.
This is because, for example, when printing red, it is sufficient to add only the MY ink, so that the image development of the image data may be performed by performing only M and Y, and stored. Is blank, so in some cases,
This is because it is possible to increase the blank band area. When the image is expanded, it is compressed and stored if necessary in consideration of the RAM capacity and the expansion time.

Next, the processing at the time of printing will be described with reference to the flowchart of FIG. When the image development of one page is completed, the processing of FIG. 7 is started. First, in step S11, the status of the printer engine 3 is checked, and if the printer engine 3 is ready for printing without a print jam or the like (ready). For example, a print start command is issued to the printer engine 3 to start printing.

At the same time, the CPU 13
The following processing is performed. That is, in step S12, the VDM
Set video parameters in AC6. This is shown in FIG.
Designation of whether the band to be printed from band 0 is blank according to the band table shown in FIG.
Of the start address, the number of transfers, and whether the image data is compressed or not are set in the VDMAC 6.

When the video parameters are set in step S12, the VDMAC 6 is activated in step S13 to start the DMA operation. The VDMAC 6 checks whether or not the specified band is a blank band. If the specified band is not a blank band, the VDMAC 6 sequentially reads data from a start address on the RAM 4. If the read image data is compressed, the VDMAC 6 reads the data. The received image data is output to the decompressor 9.

The decompressor 9 decompresses the compressed data and temporarily stores the data in the band buffer 11.
If the read image data is not compressed, the VDMAC 6 writes the read image data to the band buffer 11 as it is. Furthermore, VDMA
If the parameter set in C6 is a blank band, the image data is not read from the RAM 4
VDMAC 6 forcibly sets "0" to band buffer 11
Write to.

The engine I / F 8 reads out print data from the band buffer 11 in accordance with the print speed of the printer engine 3 and outputs it to the printer engine 3 to execute printing. When the DMA transfer of one band is completed, the VDMAC 6 generates an interrupt to the CPU 13 and notifies the CPU 13 of the end of the DMA transfer.

When the CPU 13 detects the occurrence of the interrupt in step S14, if it is not the last band in step S15, the CPU 13 returns to step S11, and returns to step S12.
To reset the parameters of the next band to VDMAC6,
In step S13, the VDMAC 6 is started. Thereafter, the same processing is performed, the processing of the final band is completed, and printing is performed until YES is determined in step S15.

When a white band is output by the VDMAC 6, the one using the system bus 5 receives image data at the host I / F 12 and buffers it in the RAM 4. Case and CPU 13
This is a case where image development of a band to be printed later is performed.

At this time, since the bus is not used in the video DMA operation, the traffic is relatively small. For this reason, image data is read out from the RAM 4 using the time between reception from the host I / F 12 and image expansion, and output to the decompressor 9 for the decompression processing for the band following the band being printed and the band following the band. This can be done in advance. This makes it easier to prevent print overrun.

By performing the above operation, printing can be performed without performing image transfer in the blank band.
When a series of jobs is completed, the job may be ended without performing the memory clear. The processing described with reference to the flow charts of FIGS. 6 and 7 applies almost similarly to the processing by the printer controller 2 shown in FIG.

[0076]

As described above, by using the printer control device (printer controller) according to the present invention, when developing image data on the RAM, the image data is divided into bands in the sub-scanning direction and processed. The image data obtained by developing the image is converted into R by the video DMA operation.
When reading from AM and sending it to the printer engine,
In the case of a white band in which no image to be printed exists, white data is automatically generated without performing a video DMA operation and output to the printer engine. It becomes possible to speed up processing by reducing traffic.

According to each of the second and subsequent inventions, the following effects can be obtained in addition to the above. According to the second aspect of the present invention, when outputting white data for a white band, the traffic on the bus is reduced. Therefore, if there is room in the RAM capacity when printing a plurality of pages, the image data of the next page and subsequent pages is output. By expanding, the expansion process can be accelerated.

According to the third aspect of the present invention, when the image data is divided into a plurality of bands and subjected to the developing process, when the image is developed without providing each band of one page on the RAM, By allocating the RAM area only to the band that needs to be expanded, that is, the band where the image data to be printed exists, there is no need to store a redundant white image in the RAM, and the capacity of the RAM can be saved and the cost can be reduced. become.

According to the fourth aspect of the present invention, by making the bandwidth for developing the image data variable, it is possible to set the bandwidth corresponding to the width of the white image in the image to be printed. For example, when printing over a wide range of text data, the width of the white band can be set in accordance with the width between lines, so that the RAM can be used more efficiently.

According to the fifth aspect of the present invention, when printing a white band, a white image can be automatically output, so that the memory clear processing normally performed after the printing is completed is not performed.
By performing the memory clear processing of the band area when it is detected that the image data exists at the time of the image development, it is not necessary to perform the memory clear processing of the unnecessary area, and the processing can be speeded up. .

According to the sixth aspect of the present invention, by compressing the data obtained by developing the image in a plurality of bands and storing the compressed data in the RAM, the use efficiency of the RAM can be further improved. During the white band printing, the bus traffic is reduced, so the image is printed on the next page and the subsequent image data is received from the host computer. By also expanding the compressed image data of the band to be processed, it is possible to increase the efficiency of the expansion processing.

According to the seventh aspect of the present invention, the image data expanded in advance by the expansion processing is temporarily stored in a memory, and the expanded image data (image data) is output from the memory during printing. As a result, it is possible to increase the efficiency of the process of outputting image data to the printer engine.

According to the eighth aspect of the present invention, when the compressed image data is decompressed, image expansion of the image data of the next page and subsequent pages and reception of the image data of the next page and subsequent pages from the host computer are performed. By lowering the priority of the bus arbitration and performing it while the bus is free, as if it were not
Processing efficiency can be improved.

According to the ninth aspect of the invention, when image development and various image processing are performed on the host computer side, for example, as in an image printer or a GDI printer,
When outputting image data from the printer driver to the printer controller, the process is performed by dividing the image data into bands, and if there is a white band, only the information indicating that the image is a white band is output. As with the printer control device, it is possible to reduce the RAM capacity and speed up image data processing.

According to the tenth aspect of the present invention, in the case of a printer control device for performing color printing,
By individually managing bands for developing image data for each color to be printed, the frequency of occurrence of white bands can be increased, and the R in the printer control device can be increased.
It is possible to reduce the capacity of the AM and reduce the cost of the color printer.

[Brief description of the drawings]

FIG. 1 is a block diagram of a printer system using a printer controller as a printer control device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a band table that records presence / absence of data of each band created on a RAM of the printer controller illustrated in FIG. 1;

FIG. 3 is a block diagram of a color printer system using a printer controller as a printer control device according to a second embodiment of the present invention.

FIG. 4 is a diagram illustrating an example of a band table created by the printer controller illustrated in FIG. 3;

FIG. 5 is an explanatory diagram showing an example of a text document and its line spacing.

FIG. 6 is a flowchart of processing relating to image development on the printer controller side shown in FIG. 3;

FIG. 7 is a flowchart of a process at the time of printing.

FIG. 8 is an explanatory diagram showing an example of an image of one page together with its main scanning direction and sub-scanning direction.

FIG. 9 is an explanatory diagram of an address map in a case where image data of the image shown in FIG. 8 is stored in a RAM by a full bitmap method.

FIG. 10 is an explanatory diagram showing an example of a band configuration when image data of the image shown in FIG. 8 is stored in a RAM by a partial bit map method.

11 is a work RAM of a plurality of bands shown in FIG.
FIG. 4 is an explanatory diagram showing an example of the above address map.

[Explanation of symbols]

 1: Host computer 2, 2 ': Printer controller 3: Printer engine 4: RAM 6: Video DMA controller (VDMAC) 7: Selector 8: Engine interface 9: Decompressor 10: ROM 11: Band buffer 12: Host interface 13: CPU

Claims (10)

[Claims] 1. A printer control device which develops image data created on a host computer and sends the image data to a printer engine to execute printing, wherein the image data is divided into a plurality of bands in the sub-scanning direction by the printer engine. Expansion processing means for dividing and developing an image on a RAM; a video DMA controller for directly accessing the RAM when outputting the developed image data to the printer engine; and outputting the image data on the RAM. Discriminating means for discriminating whether data is blank for each band; and for a band discriminated as blank by the discriminating means, white data is read without causing the video DMA controller to read out image data from the RAM. Having blank data output means for generating and outputting The printer control device according to claim. 2. The printer control device according to claim 1, wherein, when printing a plurality of continuous pages, the expansion processing unit performs processing on the video DMA controller for a band determined to be blank by the determination unit. Wherein the printer control device has means for developing an image of print data of the next page even when white data is being output. 3. A printer control device which develops image data created on a host computer, sends the image data to a printer engine, and executes printing, wherein the image data is divided into a plurality of bands in the sub-scanning direction by the printer engine. Image processing means for dividing and developing the image on the RAM, and allocating the RAM only to the band requiring the development processing; and directly accessing the RAM when outputting the image-developed image data to the printer engine, thereby increasing the speed. And a video DMA controller for generating and outputting white data for a band for which image data has not been expanded by the expansion processing means. 4. The printer control device according to claim 1, wherein said expansion processing means has means for arbitrarily setting a width of a band for developing image data into an image. Printer control device. 5. The printer control device according to claim 3, wherein said expansion processing means includes a step of:
A printer control device comprising means for performing a RAM clearing process of writing white data in an area allocated to the RAM only when an AM is allocated. 6. A printer control device for developing image data created on a host computer and sending the developed image data to a printer engine to execute printing, wherein the image data is divided into a plurality of bands in the sub-scanning direction by the printer engine. The image is decompressed on the RAM by dividing the image data, and the image data decompressed into the image is compressed,
A video DMA controller that directly accesses the RAM when outputting the image data stored in the RAM to the printer engine and outputs the image data at high speed; and the image data expanded by the expansion processing means. Determining means for determining whether or not each band is blank; and generating white data without causing the video DMA controller to read image data from the RAM for the band determined to be blank by the determining means. A blank data output unit for expanding and outputting the image image compressed by the decompression processing unit to the video DMA controller, and when the video DMA controller generates and outputs white data, Decompressing the compressed image image of the next band in advance. Printer control apparatus characterized by a means. 7. The printer control device according to claim 6, further comprising a memory for temporarily storing image data expanded by said expansion means. 8. The printer control device according to claim 6, wherein when the decompression means performs the decompression processing in advance, receiving the image data from the host computer, and decompressing and compressing the image data by the decompression processing means. A printer control device provided with means for giving priority to processing. 9. An image data generated on a host computer, which is divided into a plurality of bands in a sub-scanning direction by a printer engine by a printer driver, converted into a code system which can be interpreted by a printer control device, and developed and transmitted. In a printer control device for sending to a printer engine and executing printing, expansion processing means for splitting the image data converted and sent to the code system into the plurality of bands and developing an image on a RAM, A video DMA controller for directly accessing the RAM when outputting data to the printer engine and outputting the data at a high speed; and for a band designated as a blank band by the printer driver, the video DMA controller Without reading image data,
And a blank data output unit for generating and outputting white data. 10. The printer control device according to claim 1, wherein the rasterization processing unit rasterizes image data for printing by superimposing a plurality of colors. A printer control device comprising means for individually managing bands for developing image data for each color to be printed.