JP2000225735A - Image printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image printer capable of achieving a high speed printing process by efficiently utilizing a RAM for storing image data applied with the image development as well as by reducing the bus traffic amount. SOLUTION: In a printer controller 12, image data produced on a host computer 10 are sectioned in bands in the sub scanning direction so as to be applied with the image development in a plurality of colors as well as whether or not the band with the same image data exists in the page being developed with respect to the bands having been developed so far is judged. In the case judgment is made that the band with the same image data exists, among the bands with the same image data, only the image data of the prior band are stored in a RAM 22, and the address information. of the prior band with the same image data is recorded in the address of the latter band without storing the same image data of the latter band in the RAM 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image printing apparatus, and more particularly to an image printing apparatus for printing a color image.

[0002]

2. Description of the Related Art Generally, when an image printing apparatus is used,
After the user creates an image to be printed on the host computer, the user designates a printer for printing and issues a print command for the created image.

When a print command is issued, image data is converted into a command code system that can be interpreted by a printer controller by software called a printer driver stored in a host computer. Is output from the host computer to the host interface of the connected printer controller.

In the printer controller, when the host interface starts receiving image data to be printed, the transferred image data is stored in a RAM (Random Access Memory) by a CPU (Central Processing Unit) in the printer controller. Draw and unfold.

As a method for drawing and developing an image in the printer controller, there are a full bitmap method for storing a print image of one page as it is and a partial bitmap method for dividing a print image into bands.

For example, when an image as shown in FIG.
When storing in AM, in case of full bitmap method,
As shown in the address map of FIG. 11, one page of image data is stored as it is from the drawing start address to the drawing end address. However, the actual address map is one byte of code data, and has a configuration in which 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 a plurality of bands of the same width in the sub-scanning direction as shown in FIG. An empty area that can accommodate the band is allocated to each band, and an image is drawn. Here, the image to be printed is divided into eight bands, but the number of bands is not limited to eight, and may be any number.

By using the partial bitmap method as described above, even if it is not always possible to secure a continuous free RAM area for one page on the work RAM, the page to be printed can be stored in the band in the sub-scanning direction. And develop an image on an arbitrary RAM address. As a prior art of an image printing apparatus that performs processing using such a partial bitmap method, there is a "printer" disclosed in Japanese Patent Application Laid-Open No. 5-96794, for example.

Next, a RAM for an image to be printed by the CPU.
After the image has been developed, a print start command is issued to the printer engine, and the image data obtained by developing the image is output to the printer engine, and printing is performed.

In the case of a so-called ordinary video output for outputting an image to a printer engine, an enormous amount of data must be transferred in a short period of time. The processing speeds up.

In the case of the partial bitmap method, a DMA start address of a band to be printed and the number of transfers are designated to the video DMA controller, and the DMA operation for the set number of transfers is performed.

Further, in the video DMA controller, when the DMA transfer is completed, an interrupt for terminating the video DMA is transmitted to the CPU to notify the end. In the CPU, the DMA parameters of the following band are set again in the video DMA controller, and the same video DMA controller is set.
By performing the operation, the output to the printer engine is completed.

[0013]

By the way, in the above-mentioned conventional image printing apparatus, with the development of the laser printer engine, machines handling high-speed and high-resolution images have increased, and a color laser printer has also been developed. At present, a large capacity RAM is required for the printer controller. In addition, while the capacity of the RAM is increased, the compression technique is used to reduce the capacity of the RAM.
It has become necessary to configure a printer controller using AM.

In a conventional printer controller using the above-described partial bitmap system, image data to be printed is divided into a plurality of bands having the same width in the sub-scanning direction, and an empty area on the work RAM where the band can be accommodated. Is assigned to each band to develop the image data into a plurality of colors.At this time, even if there are a plurality of bands of the same image data between the colors,
Since it is necessary to secure a RAM having a capacity necessary to store a plurality of the same image data,
There is also a problem that the capacity of the AM needs to be increased and the cost increases.

In addition, although the image data is in the same band, it is necessary to secure a RAM having a capacity necessary to store the image image of the band. A memory clearing process for printing the next page must be performed on the area, and there is a problem that the speed of the printing process is reduced.

In a general printer controller, it is common to compress and store the image data obtained by expanding the image, and to perform expansion processing of the image data when printing by the video DMA, and output it. The traffic of the bus to which the RAM is connected is repeated by repeating unnecessary processing such as reading out the compressed image data from the RAM for each band of the same image data, outputting the data after performing the decompression processing, and the like. There is also a problem that the amount increases and the speed of the printing process is further reduced.

Further, when transferring an image from the host computer to the printer controller, the same image data must be transferred even in the case of printing by image transfer, so that the image transfer amount increases. This not only lowers the processing speed, but also increases the traffic volume of the entire network when operating in connection with a network environment.

Accordingly, the present invention has been made in view of the above-mentioned problems, and uses a RAM for storing image data obtained by developing an image efficiently, and reduces a traffic amount of a bus to speed up a printing process. It is an object of the present invention to provide an image printing apparatus capable of performing the above.

[0019]

The above object is achieved by the following image printing apparatus according to the present invention. That is, an image printing apparatus according to a first aspect is an image printing apparatus that outputs image data created on a host computer to a printer engine via a printer controller and executes printing, and wherein the printer controller is a host computer. Processing means for dividing the image data created above into bands in the sub-scanning direction and developing the data into a plurality of colors; and whether the image data developed and divided into bands by this processing means is the same for each band between the colors Discriminating means for discriminating whether or not there is a band having the same image data when the discriminating means determines that there is a band having the same image data. When outputting image data to the printer engine, the image data of the other band in the same band When outputting over data, and an outputting means for outputting the image data of the stored one of the band in the memory means.

As described above, in the image printing apparatus according to the first aspect, in the printer controller, the image data created on the host computer is divided into bands in the sub-scanning direction, developed into a plurality of colors, and further divided into bands. It is determined whether the developed image data is the same for each band for each color, and when it is determined that the same band exists for the image data, one of the bands having the same image data is determined. When the image data of the other band is stored in the storage unit, and the image data of the other band is not stored in the storage unit, and the image data of the other band is output, the one band stored in the storage unit is output. By outputting the same image data of the same band, it is possible to omit duplicating storage of image data common between bands, Since it is not necessary to store all of the opened image data in the storage unit, the capacity of the storage unit is saved, the storage unit is used efficiently, and the traffic volume of the bus when transferring the image data from the storage unit is reduced. Thus, speeding up of the printing process is realized.

According to a second aspect of the present invention, there is provided an image printing apparatus for outputting image data created on a host computer to a printer engine via a printer controller and executing printing, wherein the host computer is configured to execute the printing. Processing means for dividing the image data created on the host computer into bands in the sub-scanning direction and developing the data into a plurality of colors, and the image data developed and divided into bands by the processing means is the same for each band between the colors Determination means for determining whether or not the image data is the same band when the determination means determines that there is a band having the same image data. A storage unit for storing only image data, and a memory for storing the image data when outputting the image data to the printer engine. Out of band, in case of outputting the image data of the other bands, and an outputting means for outputting the image data of one band stored in the storage means.

Thus, in the image printing apparatus according to the second aspect, in the host computer, the image data created on the host computer is divided into bands in the sub-scanning direction, developed into a plurality of colors, and divided into bands. By determining whether or not the image data expanded in each color is the same for each band, if it is determined that the same band exists, the image data common to each band is determined. It is not necessary to duplicately transfer the image data from the host computer to the printer controller, and it is not necessary to transfer all of the image data developed in bands to the printer controller. High-speed processing is realized.

In the printer controller, only the image data of one of the bands having the same image data is stored in the storage means, and the image data of the other band is not stored in the storage means. When the image data of the band is output, the image data having the same content of one band stored in the storage unit is output. Omitting redundant storage of common image data between bands is omitted, and it is not necessary to store all of the image data expanded and divided into bands in the storage unit, so that the capacity of the storage unit is saved, In addition to efficient use, the amount of traffic on the bus when transferring image data from the storage means is reduced, and the printing process is speeded up. .

The image printing apparatus according to claim 2 is, for example, an image printer or a GDI (Graphics Device).
e Interface) It is particularly suitable for an image printing apparatus for performing image development and various image processing on the host computer side, such as a printer.

According to a third aspect of the present invention, there is provided the image printing apparatus according to the first or second aspect, wherein the processing means converts the image data created on the host computer in the sub-scanning direction for each page. The image is developed into a plurality of colors by dividing into bands, and the determination means determines whether or not the image data developed by dividing into bands for each page by the processing means is the same for each band between each color. Is characterized in that

As described above, in the image printing apparatus according to the third aspect, the processing of dividing the image data into bands in the sub-scanning direction and developing the data into a plurality of colors is performed, and the processing is performed by dividing the image data into bands in each page. By determining whether or not the same image data is the same for each band for each color in a developing page, the processing and determination can be performed easily and at high speed, thereby realizing faster printing processing. Is done.

According to a fourth aspect of the present invention, there is provided the image printing apparatus according to the third aspect, wherein the discriminating means determines that the image data developed by dividing the image data into bands for each page by the processing means is provided for each color. It is characterized in that whether or not the band is the same is determined not only within a developing page but also over a page before the developing page.

In the image printing apparatus according to the fourth aspect of the present invention, it is determined whether or not the image data expanded and divided into bands is the same for each band for each color only in the developing page. The search range is expanded by performing over the previous page of the current page, and all image data common to each band existing before the current page can be omitted. Therefore, the capacity of the storage means can be further saved, and the storage means can be used more efficiently, the traffic volume of the bus can be further reduced, and the speed of the printing process can be further increased.

According to a fifth aspect of the present invention, in the image printing apparatus according to the fourth aspect, the previous page is one page immediately before the page being developed.

If it is determined whether or not the image data developed by dividing into bands is the same for each band for each color, all the pages before the developing page are determined. It is possible to omit all the image data common to each band existing before the page, so that the capacity of the storage means is further saved, but on the other hand, the search range is enlarged too much, and on the contrary, time is required for the determination. There is a risk of cost. Also, in the page before the page being developed,
It is assumed that the probability that a band having the same image data exists is one page immediately before the page being developed.

Therefore, in order to achieve both the expansion of the search range and the speeding up of the discrimination process, and to achieve efficient use by saving the capacity of the storage means, the image data developed into bands is divided into bands for each color. It is preferable to expand the search range for determining whether or not each page is the same to one page immediately before the page being developed.

[0032]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment of the present invention will be described. (First Embodiment) FIG. 1 is a block diagram showing an image printing apparatus according to a first embodiment of the present invention. FIG. 2 is a table showing image data developed into a plurality of colors by dividing into bands in the sub-scanning direction in the printer controller.
(A) shows image data in the case of cyan, and (b) shows image data in the case of magenta. FIG.
FIG. 5 is a flowchart showing a procedure in which the printer controller determines whether or not the image data developed by dividing into bands is the same for each band for each color and stores predetermined image data. FIGS. 4A and 4B are tables showing a table for recording band assignments. FIG. 4A shows address information for cyan, and FIG. 4B shows address information for magenta.

As shown in FIG. 1, the image printing apparatus according to the present embodiment includes a host computer 10 for creating image data to be printed and a host computer 1 for creating image data.
The printer controller 12 includes a printer controller 12 that performs image development of image data created on the printer controller 0 and a printer engine 14 that executes printing based on the image data developed by the printer controller 12.

The printer controller 12 has a host interface 16 for receiving image data transferred from the host computer 10, and is connected to the host interface 16 via a system bus 18, and converts the image data into a band in the sub-scanning direction. And develops the image into a plurality of colors, and determines whether the developed image data is the same for each band between the colors, and to the CPU 20 and the host interface 16 via the system bus 18. A RAM 22 that is connected and stores image data, a ROM 24 that is connected to the CPU 20 via the system bus 18 and stores program codes for operating the CPU 20, font information used for image development of text images, and the like;
The image data read from the RAM 22 is connected to the CPU 20 and the RAM 22 via the system bus 18.
A, a video DMA controller 26 for performing the A processing, a decompressor 28 connected to the video DMA controller 26 for decompressing the compressed image data, and a RAM 22 connected to the video DMA controller 26 and the decompressor 28
A buffer buffer 30 for temporarily storing the image data read from the buffer buffer 30, and an engine interface 32 connected to the band buffer 30 and outputting print data read from the band buffer 30 to the printer engine 14. .

Next, the operation of the image printing apparatus shown in FIG. 1 will be described. First, the user of the image printing apparatus creates image data to be printed using application software running on the host computer 10. At this time, the image data created by the user includes various types of image data, such as image data extending over a plurality of pages and data created as color data.

Next, when the creation of the image data is completed, the user selects a printer that one actually wants to print from among the printable printers connected to the host computer 10 and issues a print command. I do. The print command from the user at that time includes designation of the number of print copies, designation of color or monochrome, designation of enlargement and reduction ratios, designation of paper size, and specification of a plurality of pages on one sheet of paper. This includes contents for designating various print modes, such as designation of whether or not to perform collective printing for collective printing.

When the user issues a print command in this way, the printer is connected to the host computer 10 by a printer driver stored in the host computer 10 so as to satisfy various modes specified by the user. The image data is converted into a code in a language format readable by the printer controller 12, and the image data converted into the readable code information is transferred to the host interface 16 inside the printer controller 12.

Next, in the printer controller 12, the image data transferred from the host computer 10 is received by the host interface 16 composed of a network and various interfaces. When the host interface 16 starts receiving image data, the host interface 16 generates an interrupt to notify the CPU 20 that a print command has been issued, and stores the image data received as code information by the host interface 16 in the RAM 22. Buffer and temporarily store.

In the CPU 20, the RAM 2
In order to make the image data buffered as code information 2 printable in the printer engine 14, the image data is developed and converted into bitmap information. At that time, the image data is virtually developed into a plurality of colors by dividing the image data into bands in the sub-scanning direction of the printer engine 14.

More specifically, as shown in FIGS. 3A and 3B, for example, image data of one page being developed is transferred from band 0 to band 7 in the sub-scanning direction of the printer engine 14.
The image is developed by dividing into 8 bands. In addition, 1
When one character C extends over a plurality of bands of band 3 and band 4, character C is decomposed into two and image development is performed.

When the image data is color, the image handled by the host computer is usually RGB (Red, Gr,
een, Blue; red, green, blue), but when printing, CMYK (Cyan, Mangenta, Yellow, Bla
ck; blue-green, magenta, yellow, black)
The image data is divided into MYK color components, and further divided into bands for processing. Here, as shown in FIGS. 3A and 3B, images are developed in the order of cyan and magenta.

Subsequently, the CPU 20 determines whether or not the image data expanded and divided into bands is the same for each band for each color. That is, as shown in the flowchart of FIG. 3, it is determined whether or not a band having the same image data exists in the page under development by comparing with the band developed so far (step 1).

In the cyan band 0 to band 7 shown in FIG. 2A, if the same band of image data is not present in the developing page, the image data for one band is stored in the RAM 22. A RAM space having a capacity that can be allocated is allocated, and the RAM is cleared by writing “0” into the allocated RAM space. At this time, any address may be assigned to the RAM space as long as it is an area where one band is continuous. Further, in order to memorize that each band is allocated, as shown in FIG. 4A, the start address and the end address of the cyan band 0 to the band are recorded in a table (step 2).

Also, in the case of magenta band 0 to band 7 shown in FIG. 2B, the image data of magenta band 0 is the same as the image data of cyan band 0 shown in FIG. 2A. Does not allocate a RAM space for storing image data of magenta band 0 in the RAM 22. As shown in FIG. 4B, the start address and end address of magenta band 0 The same start address and end address are recorded (step 3). Hereinafter, the same applies to magenta bands 1 to 7.

As described above, when it is determined that a band having the same image data exists as compared with the bands developed up to that time, among the bands having the same image data,
Only the image data of the previously existing band is stored in the RAM 22, and the image data of the subsequent band having the same image data is R
The address information of the previous band having the same image data is recorded in the address of the subsequent band without storing it in the AM 22.

Therefore, it is not necessary to secure a frame memory for one page in advance when dividing into bands, and it is possible to adopt a configuration in which only bands that need to be developed are allocated to the RAM 22 and then developed. RA
The memory area of M22 is used efficiently. Also, by performing memory clear only when allocating a band, it is not necessary to perform multiple memory clear processes, and it is possible to perform efficient processes. Furthermore, when the image data is color, the image is usually developed in a plurality of colors. For example, when the color to be developed is red, only M and Y need to be developed. By performing the processing in a divided manner, there is no need to secure a redundant memory area in the RAM 22.

Next, at the same time as the CPU 20 develops the image in the RAM 22, the image data stored in the RAM 22 is compressed as necessary and stored in the RAM 22 again. However, the printer controller 12 need not always be capable of compression, and even in an environment where compression is possible, if the RAM capacity is large and sufficient storage is possible, the image data is stored as it is without compression. In some cases. Note that there are two types of compression methods: a method using a dedicated compressor and a method using the CPU 20.

Next, when all the image development (compression in some cases) of one page of the image data received by the CPU 20 is completed, the CPU 20 causes the video DMA controller 26 to perform video DMA. After setting various parameters in accordance with the tables (a) and (b), a command to start the video DMA is issued. The parameters to be set include designation of a start address on the RAM 22 for performing the DMA operation,
There are designation of the number of transfers at the time of transfer, designation of whether or not image data to be subjected to video DMA is compressed, and the like.

With such a configuration in which the number of transfers can be arbitrarily changed, an arbitrary bandwidth can be specified. Further, using the address information stored when the image data detects the same band, the image data of the band that existed earlier is used for the subsequent band of the same image data. This makes it possible to save memory.

In the video DMA controller 26, when each parameter is specified and the DMA is started, the image data is sequentially read from the specified start address on the RAM 22, and the read image data is written to the band buffer 30 as it is. To temporarily memorize it.

At this time, if the image data read from the RAM 22 is compressed, the read image data is output from the video DMA controller 26 to the decompressor 28. Generally, the printer engine 1
4, the image data to be output must be treated as image data, and a large amount of data must be transferred in a short period of time.
If the CPU 20 performs the expansion processing of the reduced image data, a print overrun occurs. Therefore, when performing the video DMA, a dedicated expander 28 is used.

The dedicated decompressor 28 decompresses the image data transferred from the video DMA controller 26 using a method opposite to the method of compressing the image data, and then stores the decompressed image data in a band buffer. 30 is temporarily stored.

Next, the status of the printer engine 14 is detected, and if the printer engine 14 has no print jam or the like and is in a printable state, a print start command is issued to the printer engine 14 via the engine interface 32. .

The engine interface 32 reads out image data from the band buffer 30 according to the printable resolution and speed of the printer engine 14 and outputs the image data to the printer engine 14.

In the printer engine 14,
Execute printing of the transferred bitmap data,
Complete printing. By performing the above operation for all the bands in one page, printing of the image for one page is completed.

When the DMA transfer of one band is completed, the video DMA controller 26
Generates an interrupt to notify the end of the DMA transfer.
Then, when the CPU 20 detects an interrupt, the parameters of the next band are reset in the video DMA controller 26, and thereafter, the same processing is performed, and printing is performed up to the last band.

However, when printing is performed over a plurality of pages,
When the image development of the previous page is completed and the print processing is performed by the video DMA operation, the system bus 18
Performs parallel processing to develop the image of the next page using the time when is available. In this way, the printing process is completed when printing of all pages is completed. By performing the above operation, printing can be performed without duplicating image transfer of the same band of image data.

As described above, according to the image printing apparatus of this embodiment, the printer controller 12 divides the image data created on the host computer 10 into bands in the sub-scanning direction of the printer engine 14 to form a plurality of colors. In addition to the image development, it is determined whether or not a band with the same image data exists by comparing with the band developed so far in the page under development, and it is determined that the band with the same image data exists. In the case where the image data is the same, only the image data of the band that existed earlier in the same band is stored in the RAM 22, the image data of the subsequent band having the same image data is not stored in the RAM 22, By recording the address information of the previous band with the same image data at the address of There is no need to secure a frame memory for a page, and it is possible to allocate only the band required for image development to the RAM 22 and then develop the band. Therefore, the capacity of the RAM 22 can be saved and the memory area can be efficiently used. Can be used

Further, of the bands having the same image data,
When the image data of the subsequent band is output to the printer engine 14, the image data of the same content stored in the address of the band existing before is output, so that the image data common to each band is duplicated. Since the transfer and the output are omitted, the traffic amount of the system bus 18 is reduced, and the speed of the printing process can be increased.

(Second Embodiment) FIG. 5 is a table showing image data developed into a plurality of colors by dividing into bands in the sub-scanning direction in a printer controller of an image printing apparatus according to a second embodiment of the present invention. (A) is the image data of the previous page in the case of cyan, (b) is the image data of the previous page in the case of magenta, (c) is the image data of the developing page in the case of cyan, (D) shows image data of a developing page in the case of magenta. 6A and 6B are tables showing a table for recording band assignments. FIG. 6A shows the address information of the previous page in the case of cyan, FIG. 6B shows the address information of the previous page in the case of magenta, and FIG. Indicates the address information of the developing page in the case of cyan, and (d) indicates the address information of the developing page in the case of magenta.

In the image printing apparatus according to the present embodiment, the image data obtained by developing the image printing apparatus in the printer controller 12 into the bands in the image printing apparatus according to the first embodiment is the same for each band for each color. When determining whether or not there is a band with the same image data compared to the bands that have been developed so far in the page being developed, the search range Is distinguished not only in the page under development, but also up to one page immediately before the page under development (hereinafter simply referred to as “previous page”).

That is, the image printing apparatus according to the present embodiment
In the printer controller 12, when the image data is developed into an image and converted into bitmap information in the same manner as in the first embodiment, the image data is virtually divided into bands in the sub-scanning direction. Image development to the color of.

More specifically, as shown in FIGS. 5C and 5D, the image data in the developing page is divided into eight bands from band 0 to band 7 in the sub-scanning direction of the printer engine 14. And develop the image in the order of cyan and magenta. At this time, the image data in the previous page of the page being developed includes, for example, eight bands from band 0 to band 7 in the sub-scanning direction of the printer engine 14 as shown in FIGS. It is assumed that the image is developed in the order of cyan and magenta.

Then, the respective bands 0 to 7 of cyan and magenta on the previous page of the developing page
The start address and the end address of FIG.
It is recorded as shown in the table of (b).

Subsequently, the CPU 20 determines whether or not the image data developed by dividing into bands is the same for each band for each color. At this time, not only in the page being developed, but also in the page being developed. The search range is expanded to the previous page, and it is determined whether or not a band having the same image data exists.

More specifically, for example, FIGS.
As shown in (c) and (d), when the image data of each band 1 of cyan and magenta of the developing page is the same as the image data of band 0 of cyan and magenta of the previous page, As shown in the tables of FIGS. 6C and 6D, the address information of each band 1 of cyan and magenta of the developing page is as follows.
The same start address and end address as the cyan and magenta band 0 address information of the previous page recorded in the tables of FIGS. 6A and 6B are recorded.
By repeating such an operation, image development is performed for all color bands of one page being developed.

As described above, according to the image printing apparatus of this embodiment, when the printer controller 12 determines whether or not the image data expanded and divided into bands is the same for each band for each color. The search range is expanded and determined by expanding the search range not only within the developing page but also to the previous page where image data is presumed to have the highest probability that the same band exists. , The capacity of the RAM 22 can be further reduced, and the memory area can be used more efficiently.

(Third Embodiment) FIG. 7 shows image data developed in a sub-scanning direction in a host computer of an image printing apparatus according to a third embodiment of the present invention. 9 is a flowchart showing a procedure for determining whether or not the image data is the same and storing predetermined image data. FIG. 8 shows whether the image data developed in the sub-scanning direction in the host computer of the image printing apparatus according to the third embodiment of the present invention is the same for each band for each color. 4 is a chart showing a table for recording predetermined band information. FIG. 9 is a chart showing a memory map created in the host computer of the image printing apparatus according to the third embodiment of the present invention.

In the image printing apparatus according to this embodiment, the image printing apparatus according to the first embodiment develops the image data into a plurality of colors by dividing the image data into bands in the sub-scanning direction in the printer controller 12 thereof. While it is determined whether or not the image data developed by dividing into bands is the same for each band for each color, such image data is divided into bands in the sub-scanning direction and developed into multiple colors. The feature is that the host computer 10 performs a process of determining whether or not the image data expanded and divided into bands is the same for each band between the colors.

That is, the image printing apparatus according to the present embodiment
After converting the image data created on the host computer 10 into a code in a language format readable by the printer controller 12 using a printer driver, the image data converted to the readable code information is sent to the printer controller 12. At this time, if the emulation that can be decoded by the printer controller 12 is transferred directly from the printer driver to the emulator in the form of a band as in a GDI printer system, the image data is transferred to the printer controller 12. Before the transfer, it is determined whether or not the image data developed by dividing the image into bands is the same for each band for each color.

Specifically, as shown in the flowchart of FIG. 7, the host computer 10 virtually divides the image data into bands in the sub-scanning direction, develops the images into a plurality of colors, and develops the image of each band. In the page where the data is being developed, it is compared with the image data of the bands that have been developed so far to determine whether or not a band having the same image data exists (step 1).

Then, the result of the determination is recorded as information of each band in the table shown in FIG. For example,
When it is determined that the image data of the band 0 of magenta does not exist, as shown in FIG. 8, for example, "band 0 of magenta" is displayed in the band information column.
And the information of the band itself is recorded, "None" is recorded in the column of the same band information, and the image data of the band is stored (step 2).

If it is determined that there is a band with the same image data, as shown in FIG. 8, for example, "magenta band 0" and the information of the band itself are recorded in the band information column. In the same band information column, for example, only "same as cyan band 0" is recorded, and the image data for the band is not stored (step 3).

In this way, a memory map as shown in FIG. 9, for example, is created. That is, cyan band 0
As a result of comparing the image data with the image data of the bands developed so far, if it is determined that there is no band of the same image data as the image data of the cyan band 0, “Cyan band 0” is recorded in the band information column, “none” is recorded in the same band information column, and the image data for that band is stored. Similarly, when it is determined that there is no band of the same image data as the cyan band 2, “Cyan band 2” and the same band information Is recorded as "None" and the image data for the band is stored.

If it is determined that a band of the same image data as that of the magenta band 0, for example, the band 0 of cyan exists, the band information of the band 0 of magenta is displayed in the column of the band information of the band 0 of magenta. Band 0 "
, And only “Same as cyan band 0” is recorded in the same band information field, and image data for the band is not stored.

If it is determined that no band of the same image data as the magenta band 1 exists, "magenta band 1" is recorded in the band information column of the magenta band 1. Then, “None” is recorded in the column of the same band information, and the image data for the band is stored.

Next, the image data processed as described above is transferred from the host computer 10 to the printer controller 12 (step 4). For this reason, the host computer 10 does not transfer all of the image data developed into a plurality of colors by dividing the image data into bands in the sub-scanning direction, and the image data common between the bands is not transferred. become.

When the image data transferred from the host computer 10 is stored in the RAM 22 in the printer controller 12, first, as shown in FIG. 4 above, according to the information of each band recorded in the table of FIG. After storing the address information in a simple table,
Write to AM22. That is, it is determined whether image data is included in the band transferred from the host computer 10 (step 5).

When it is determined that the image data is included in the band, the image data of the band is allocated to the RAM 22 and the fact that the image data of the band is allocated is stored. , The start address and end address of the band are recorded in a table (step 6). If it is determined that the band does not include image data, the start address and the end address of the band are recorded in a table without assigning the image data of the band to the RAM 22 (step 7). .

As described above, according to the image printing apparatus of this embodiment, the host computer 10 divides the image data created on the host computer 10 into bands in the sub-scanning direction of the printer engine 14 to form a plurality of colors. And determines whether or not there is a band with the same image data by comparing with the bands that have been developed up to that point in the page being developed, and determining whether there is a band with the same image data. When the image data is transferred, only the information of the band is recorded, the image data of the band is not stored, and when the image data is transferred from the host computer 10 to the printer controller 12, the image data common to the bands is transferred. Since the transfer is omitted, all of the image data developed in bands is 10 printer controller 12 from
Since it is not necessary to transfer the image data, the transfer amount of the image data is reduced, and the speed of the printing process can be increased.

When the image data transferred from the host computer 10 is stored in the RAM 22 in the printer controller 12, the address information of each band is first stored in accordance with the information of each band recorded. By writing the image data into the RAM 22, the capacity of the RAM 22 can be saved and used efficiently, and the traffic amount of the system bus 18 can be reduced, so that the printing process can be speeded up.

[0082]

As described above, according to the image printing apparatus of the present invention, the following effects can be obtained. That is, according to the image printing apparatus of the first aspect, in the printer controller, the image data created on the host computer is divided into bands in the sub-scanning direction and developed into a plurality of colors, and the image data is developed into bands. It is determined whether or not the image data is the same for each band for each color, and when it is determined that the same band exists for the image data, the image data is determined to be one of the same bands. Is stored in the storage means, and the image data of the other band is not stored in the storage means. When outputting the image data of the other band, the same data of one of the bands stored in the storage means is output. By outputting the image data of the content, the image data common to each band can be omitted from being redundantly stored. Since it is not necessary to store all of the opened image data in the storage means, the capacity of the storage means can be saved and used efficiently, and the traffic volume of the bus when transferring the image data from the storage means And the speed of the printing process can be increased.

According to the image printing apparatus of the second aspect, the host computer develops the image data created on the host computer into a plurality of colors by dividing the image data into bands in the sub-scanning direction. When it is determined that the same image data exists for each band by determining whether or not the image data expanded and divided is the same for each band, the image data common to each band is determined. Since the transfer of the image data from the host computer to the printer controller in duplicate is omitted, it is not necessary to transfer all of the image data developed in bands to the printer controller, and the transfer amount of the image data is reduced. As a result, the speed of the printing process can be increased.

In the printer controller, only the image data of one band of the same band whose image data is the same is stored in the storage means, and the image data of the other band is not stored in the storage means. When the image data of the band is output, the image data having the same content stored in the address of one band is output. Since it is not necessary to store the image data which is common among the image data redundantly, it is not necessary to store all of the image data expanded and divided into bands in the storage means. Can be used efficiently, and the amount of traffic on the bus when transferring image data from the storage means is reduced. It is possible to realize a high speed.

According to the image printing apparatus of the third aspect, the processing of dividing the image data into bands in the sub-scanning direction and developing the data into a plurality of colors is performed for each page, and the processing is performed by dividing the image data into bands for each page. When determining whether or not the image data is the same for each band for each color, by performing the determination processing in the developing page, the processing and determination can be performed easily and at high speed. Therefore, the speeding up of the printing process can be realized.

According to the image printing apparatus of the present invention, when it is determined whether or not the image data expanded and divided into bands is the same for each band for each color, the determination processing is expanded. By performing not only within the inside page but also to the page before this developing page,
The search range is expanded, and it becomes possible to omit all the image data common to each band existing before the page under development, so that the capacity of the storage means can be further reduced and used more efficiently. In addition to this, the traffic volume of the bus can be further reduced, and the speed of the printing process can be further increased.

According to the image printing apparatus of the present invention, the processing for determining whether or not the image data expanded and divided into bands is the same for each band between the colors is performed only in the developing page. Instead, when the search is performed across the page before the page being expanded, the search range is expanded to the previous page of the page being expanded as the previous page, thereby determining that the search range is expanded. It is possible to achieve both efficient processing and efficient use of the storage means by saving the capacity.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an image printing apparatus according to a first embodiment of the present invention.

FIGS. 2A and 2B are tables showing image data developed into a plurality of colors by dividing into bands in the sub-scanning direction in a printer controller of the image printing apparatus according to the first embodiment of the present invention; FIG. (B) shows the image data in the case of magenta.

FIG. 3 is a diagram illustrating a predetermined image by determining whether or not image data expanded and divided into bands is the same for each band for each color in the printer controller of the image printing apparatus according to the first embodiment of the present invention. 5 is a flowchart illustrating a procedure for storing data.

FIG. 4 is a table showing a table for recording band assignments in the image printing apparatus according to the first embodiment of the present invention, wherein (a) shows address information in the case of cyan;
(B) shows address information in the case of magenta.

FIG. 5 is a table showing image data developed in a plurality of colors by dividing into bands in the sub-scanning direction in a printer controller of an image printing apparatus according to a second embodiment of the present invention; If the image data of the previous page,
(B) shows the image data of the previous page in the case of magenta,
(C) shows the image data of the developing page in the case of cyan, and (d) shows the image data of the developing page in the case of magenta.

FIGS. 6A and 6B are tables showing a table for recording band assignments in the image printing apparatus according to the second embodiment of the present invention, wherein FIG. 6A shows address information of a previous page in the case of cyan, and FIG. Indicates the address information of the previous page in the case of magenta, (c) indicates the address information of the developing page in the case of cyan, and (d) indicates the address information of the developing page in the case of magenta. .

FIG. 7 is a diagram showing a predetermined image by determining whether or not image data expanded and divided into bands is the same for each band for each color in the host computer of the image printing apparatus according to the third embodiment of the present invention. 5 is a flowchart illustrating a procedure for storing data.

FIG. 8 is a diagram showing a predetermined band determined by determining whether or not image data expanded and divided into bands is the same for each band for each color in the host computer of the image printing apparatus according to the third embodiment of the present invention. 4 is a chart showing a table for storing information and recording.

FIG. 9 is a chart showing a memory map created in a host computer of an image printing apparatus according to a third embodiment of the present invention.

FIG. 10 is a diagram showing an image stored in a RAM of a conventional image printing apparatus.

FIG. 11 is a diagram showing an address map of an image stored in a RAM of a conventional image printing apparatus by a full bitmap method.

FIG. 12 is a table showing image data developed and divided into bands in the sub-scanning direction by a partial bitmap method in a conventional image printing apparatus.

FIG. 13 is a chart showing a memory map created in a conventional image printing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Host computer 12 Printer controller 14 Printer engine 16 Host interface 18 System bus 20 CPU 22 RAM 24 ROM 26 Video DMA controller 28 Decompressor 30 Band buffer 32 Engine interface

Claims (5)

[Claims] 1. An image printing apparatus that outputs image data created on a host computer to a printer engine via a printer controller and executes printing, wherein the printer controller is created on the host computer. Processing means for dividing the image data into bands in the sub-scanning direction and developing the data into a plurality of colors; and determining whether or not the image data developed and partitioned into bands by the processing means is the same for each band between the colors. Determining means; storing means for storing only image data of one of the bands having the same image data when the determining means determines that there is a band having the same image data; When outputting to the printer engine, the image data of the other band of the same band is output. When the image printing apparatus characterized by an output means for outputting the image data of one band stored in the storage means. 2. An image printing apparatus that outputs image data created on a host computer to a printer engine via a printer controller and executes printing, wherein the host computer is created on the host computer. Processing means for dividing the image data into bands in the sub-scanning direction and developing the data into a plurality of colors; and determining whether or not the image data developed and partitioned into bands by the processing means is the same for each band between the colors. Determining means;
When the printer controller determines that the same band exists with the same image data by the determination unit,
A storage unit for storing only image data of one of the bands having the same image data, and outputting the image data of the other band among the bands having the same image data when outputting the image data to the printer engine. Output means for outputting image data of one band stored in the storage means when outputting. 3. The image printing apparatus according to claim 1, wherein the processing unit divides the image data created on the host computer into bands in the sub-scanning direction for each page and develops the image data into a plurality of colors. The determining means determines whether or not the image data expanded and divided into bands for each page by the processing means is the same for each band between each color in a developing page. Image printing device. 4. The image printing apparatus according to claim 3, wherein the determination unit determines whether or not the image data developed by dividing the image data into bands for each page is the same for each band for each color. An image printing apparatus characterized in that the determination is performed not only within a developing page but also over a page before the developing page. 5. The image printing apparatus according to claim 4, wherein the previous page is one page immediately before the developing page.