JP3472057B2 - Output control apparatus and method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an output control apparatus and method for receiving PDL data, expanding the data, and outputting the expanded data.

[0002]

2. Description of the Related Art Conventionally, when printing image information generated using a drawing application executed on a host computer, the image information is converted into print data in PDL (page description language) and then communicated. It is transmitted to a printer device via a cable or the like and printed. Such a printer device is provided with a controller capable of controlling the entire device and expanding the PDL, and the controller receives the print data described in the PDL from the host computer and expands the received print data into bitmap data. , Is passed to the printer engine interface.

A double buffer for temporarily storing the bitmap data is provided in the portion for supplying the bitmap data to the printer engine, and one buffer is used for writing the data in which the PDL is expanded and the other buffer is used. The buffers are used to supply data to the printer engine, and it is common practice to switch between these two buffers.

[0004]

However, when the printer device is a high-speed printer such as an LBP (laser beam printer), the printing speed is much higher than that of an inkjet or thermal printer device, so that the PDL data is not printed. There are often situations in which the deployment speed of the is not in time for the output (shipping) speed to the printer engine. Especially in the case of LBP or the like, once the printing operation is started, it is impossible to put it in a standby state during the process. Therefore, PD
When the L data development process is not in time for the printing speed, printing is performed before the print data is completely developed, and a normal print image cannot be printed.

In order to prevent such a situation, such a PDL data expansion buffer is prepared for one page of print data, one page of PDL data is expanded, and a bitmap image is created in the expansion buffer. It is conceivable to start the printing process for one page after storing the. However, provision of such a large-capacity page buffer increases the cost of the entire apparatus. Therefore, in order to save the memory capacity of the decompression buffer, the decompressed bitmap image may be compressed once and stored in a predetermined memory, and then decompressed / outputted in accordance with the image output to the printer device. Proposed. However, there is no suitable compression method for efficiently using a predetermined memory capacity. On the other hand, there is also a problem that the throughput of the printing process (the number of pages to be printed per unit time) must be reduced in order to match the speed of the compression / decompression process proposed above.

The present invention has been made in view of the above conventional example, in which PDL data for one page is divided into a plurality of times.
If you want to receive it, develop it, and print it by a predetermined method,
Image data developed while suppressing image quality deterioration.
In addition to making it possible to efficiently hold the compressed state,
So that it can be done as quickly as possible.
aimed to.

The present invention also allows the compression rate to be freely changed.
The further purpose is to do.

[0008]

[0009]

The output control device of the present invention is
It has the following configuration. That is, P for one page
A receiving means for receiving the DL data divided into a plurality of times,
The PDL data received by the receiving means is expanded and the image data is
And the image data obtained by the developing means.
A first storage means for storing data, and the first storage means
Means for compressing the compressed image data, and said compression means
Second storage means for storing the compressed data obtained in
Decompressor for decompressing the compressed data stored in the second storage means
And the decompressed data obtained by the decompressing means are printed in a predetermined manner.
Means or output means for outputting to the first storage means, and
What is the PDL data received by the receiving means among the plurality of times?
Depending on whether it is the first time,
Controlling means for controlling the receiving means,
In the first reception by the communication means, it was received at that time.
The PDL data is expanded by the expansion means, and the
The image data obtained by opening is stored in the first storage means.
Compress the stored image data by the compression means.
The compressed data obtained by the compression is stored in the second storage means.
Control so that it is stored in the
In each reception from the last to the last one,
Obtained by the reception before the current reception stored in the memory
The compressed data is decompressed by the decompression means and obtained by the decompression.
The decompressed data obtained by the output means by the first memory.
And outputting the expanded data to the first storage means.
Stored in the PDL data received at that time
Image data obtained by the expansion by the expansion means
Overwriting the decompressed data stored in the first storage means.
Image data obtained after the overwriting storage
The compressed data obtained by the compression by the compression means.
Control to store the data in the second storage means,
In the final reception by the communication means, the second memory
Compression obtained by reception before the current reception stored in the column
The data is expanded by the expansion means, and the expansion obtained by the expansion is performed.
The long data is output to the predetermined printing means by the output means.
And expand the PDL data received at that time.
The image data obtained by the expansion is forwarded.
It is stored in the first storage means and stored in the first storage means.
Image data without passing through the compression means and decompression means.
It is characterized by controlling to output to a predetermined printing means.
To do.

The output control method of the present invention is as follows.
It has a simple structure. That is, PDL data for one page
And a receiving step of receiving by dividing into a plurality of times.
Expand the PDL data received in to develop image data
Decompression process and compressing the image data
The compression step to obtain and the decompressed data by decompressing the compressed data
And a decompression process for obtaining the decompression data by a predetermined printing means or
An output step of outputting to the first memory, and the receiving step
The PDL data received in
Control that controls the execution of each of the above steps, depending on
And a control step according to the receiving step.
For the first reception, the PDL data received at that time
Was obtained by the development step described above.
Image data is stored in the first memory, and the stored image is stored.
The image data is compressed by the compression step and obtained by the compression.
Control to store the compressed data stored in the second memory.
However, from the second time to the last time before the last time by the receiving process
In each reception of, the relevant memory stored in the second memory
Compressed data obtained before the first reception
The extension data obtained by the extension is
The expansion is performed by outputting to the first memory in the output step.
The long data is stored in the first memory and is received at that time.
The PDL data is expanded by the expansion process,
Image data obtained by expansion has been stored in the first memory
After the overwriting is stored in the expanded data of
The obtained image data is compressed by the compression step,
Store the compressed data obtained by compression in the second memory
Control in the final reception by the receiving step.
Is stored in the second memory before the reception of that time.
The compressed data obtained by the decompression is decompressed by the decompression step.
And the decompressed data obtained by the decompression
The PDL data received at that time is output to a predetermined printing means.
The deployment of the data is performed by the deployment process, and obtained by the deployment.
Stored image data in the first memory,
The image data stored in the memory is subjected to the compression process and decompression process.
Control to output to the predetermined printing means without any delay.
It is characterized by

[0011]

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the present embodiment, an example in which print data is output to a printer device will be described, but the present invention is not limited to this. For example, a display that receives image data, develops the image data, and displays the image data, It can also be applied to a device that outputs to a line or the like. Also,
The printer device is not limited to the laser beam printer according to the present embodiment, and can be applied to, for example, another inkjet printer or a thermal printer.

[First Embodiment] FIG. 1 is a block diagram showing the arrangement of a printing system according to the present embodiment.

In FIG. 1, reference numeral 1 is a host computer, drawing data is created by a drawing application or the like executed by the computer 1, and the drawing data is PD
It is converted into L data and transmitted to the controller 14.
Reference numeral 13 is a color printer such as an LBP or an inkjet printer, which inputs the bitmap data from the controller 14 to print a color image.

Next, the configuration of the controller 14 of this embodiment will be described. The controller 14 may be incorporated in the color printer 13 or the host computer 1, and may be interposed between the host computer 1 and the color printer 13.
They may be separate from these.

A CPU 2 controls each part of the controller 14 based on a control program (flowcharts in FIGS. 2 to 4) stored in the memory 2a. The memory 3 stores the received PDL data and a display list recreated in a format that can be processed by the rendering unit 4 that develops the PDL data. Reference numeral 5 denotes a band buffer in which rendering data (bitmap data) obtained by rendering the PDL for each band in the rendering unit 4 is written. A memory management unit 6 controls reading of the band buffer 5. A lossless / lossy compression unit 7 inputs the bit map data (expanded data) stored in the band buffer 5 and compresses it. The details of the lossless / lossy compression unit will be described later. A compression memory 10 stores the compression data compressed by the lossless / lossy compression unit 7. 11 is a lossless extension part,
It operates when outputting print data (image data) to the color printer 13 or when transferring data to the band buffer 5 which will be described later, reads the compressed data stored in the compression memory 10 and decompresses it to convert it into image data. is doing. Reference numeral 12 denotes a printer processing unit that prints print data to be output to the color printer 13 to the color printer 1.
Processing such as conversion into data according to the print characteristics of No. 3 and output is performed. Reference numeral 17 is an external storage device such as a floppy disk driver, and 18 is a magnetic storage medium such as a floppy disk or a hard disk.
~ A control program for executing the processing shown in the flowchart of Fig. 4 is stored, and this program is downloaded to the memory 2a and executed.

Next, the operation of the printing system described above is performed by PDL data (page output data in page description language) created by a drawing application executed by the host computer 1, or by another device or system. A case will be described in which the PDL data is once taken in by the host computer 1 and an instruction to print the PDL data is given.

The controller 14 receives the PDL data from the host computer 1 and writes it in the memory 3.
At this time, the CPU 2 uses the description language of one page to describe this PDL data in band units by dividing one page into a plurality of horizontal lines (a plurality of scanning lines), and in a data format that the rendering unit 4 can interpret. It is converted into a display list and written in the memory 3. Then, the rendering unit 4 is activated. When creating the display list, the RGB data included in the PDL is converted into YMCK data. The rendering unit 4 performs bitmap expansion processing to the band buffer 5 based on this display list.

Further, the rendering unit 4 is 3 at the final stage.
Dither processing is performed using one threshold value matrix, and 2-bit 4-valued data is expanded in the band buffer 5. This expansion process is performed by the color printer 13 for each band to be processed.
Output colors Y, M, C, K in this order for all four colors. The band buffer 5 can be divided into two parts for use, and one part is used for writing decompressed data, and the other part is a lossless / lossy compression part 7.
It can be used as a so-called double buffer in which writing and reading are switched for each data processing for each band. In response to such buffer switching, the memory management unit 6 controls the reading of data from the band buffer 5, and the rendering unit 4 controls the writing of data to the band buffer 5.

In this way, one band of Y, M, C,
When the processing for the K data is completed, the Y, M, C, K expansion processing for the next band is repeated.

The reason for completing the Y, M, C, K processing for each band here is that the display list for that band is discarded after the Y, M, C, K four colors have been developed.
This is to create an empty area in the memory 3.

In the present embodiment, the memory 3 and the compression memory 10 are shown separately in the block diagram of FIG.
Memory that is physically the same memory and that can be simultaneously accessed from two or more blocks may be used. By doing so, the empty area of the memory 3 can be effectively utilized as it is as the area of the compression memory 10, and the total capacity of the memory can be reduced.

The data expanded in the band buffer 5 as described above is compressed by the lossless / lossy compression unit 7 and stored in the compression memory 10. When the print data is output to the color printer 13 (during shipping)
The compressed data corresponding to the color and band to be printed out stored in the compression memory 10 is the lossless decompression unit 11.
And the expanded print data is processed by the printer processing unit 12 and output to the color printer 13. The color printer 13 prints a color image by controlling the gradation of one pixel by pulse width modulation.
When the resolution of the horizontal pixels in the color printer 13 can be apparently increased, the printer processing unit 12 increases the resolution of the horizontal pixels to perform smoothing processing such as smoothing the jagged edges of the image. .

By the way, when the capacity of the PDL data input from the host computer 1 is too large, the controller 14 receives the PDL data in a plurality of times within the allowable range of the memory 3. This is called sub-close.
The sub-close will be described below.

This sub-close is the PDL for one page.
Is divided into a plurality of blocks to receive the PDL data by dividing the PDL data into a plurality of blocks, and finally the print data for one page is stored in the compression memory 10 in the compressed format. That is,
The PDL data received the first time is expanded according to the above-described expansion method, but the PDL data of the second and subsequent blocks is expanded and compressed and stored in the compression memory 10. The compressed data that has been compressed is decompressed by the lossless decompression unit 11, and the subclose path 1
After 5, the data is written in the band buffer 5 as the previous PDL data. Then, the rendering unit 4 overwrites the received next PDL data on the band buffer 5. As a result, the connection with the previously compressed / decompressed image data becomes continuous, and the continuity of the image is not impaired. In this case, writing is not performed in the portion where the relationship of overlap is lower. Then, the result compressed by the lossless / lossy compression unit 7 is written again in the compression memory 10. In this manner, the PDL data that is divided into one page and received is expanded, and the compressed data for one page is stored in the compression memory 10. Output (shipping) is performed. In this shipping process, as described above, the lossless decompression unit 11 decompresses the compressed data of the appropriate color and band in the compression memory 10 and outputs the print data to the color printer 13 via the printer processing unit 12.

FIG. 2 shows the controller 14 of this embodiment.
2 is a flowchart showing a one-page printing process using the sub-closed path 15 in FIG. In this process, one-page print data is divided into a plurality of blocks, PDL data corresponding to each block is sequentially sent, and finally one is written to the compression memory 10.
After the page print data is stored as compressed data,
It is shown in the case where it is printed.

First, in step S1, when PDL data is received from the host computer 1, the received data is stored in the memory 3, expanded by the rendering unit 4 into original image data, and stored in the band buffer 5. Step S
In 3, under the control of the memory management unit 6, the received and expanded image data is read, compressed by the lossless / lossy compression unit 7, and stored in the compression memory 10.

Next, in step S4, the compressed data previously stored in the compression memory 10 is read out and decompressed by the lossless decompression unit 11. In step S5, the next block of PDL data is received and expanded by the rendering unit 4,
The image data expanded in step S4 is stored in the band buffer 5 (S6). Then, the process proceeds to step S7, the decompressed data corresponding to the PDL data received this time is read from the band buffer 5, compressed by the lossless / lossy compression unit 7, and stored in the compression memory 10. In this way, the compressed data corresponding to the received PDL data block is sequentially written in the compression memory 10.

In this way, the process proceeds to step S8, the processes of steps S4 to S8 are executed until the processing of the image data for one page is completed, and when the compressed image data for one page is stored in the compression memory 10, the step is performed. In step S9, the compressed data stored in the compression memory 10 is decompressed, and the color printer 13 is decompressed via the printer processing unit 12.
And the image is printed.

Next, the real-time through path 16 which is another feature of this embodiment will be described.

The real-time through path 16 is a path that directly connects the data from the memory management section 6 to the printer processing section 12 and bypasses the part related to compression and decompression. Note that such path switching is performed under the control of the CPU 2.

When the PDL data expansion process in the rendering unit 4 is faster than the printing speed in the color printer 13, the rendering unit outputs the data in the band buffer 5 to the color printer 13 via the printer processing unit 12. 4 is divided into two by dividing the band buffer 5 into two by writing the expansion data to the other buffer while one buffer is reading to the color printer 13. Alternately, the buffer (double buffer) is switched for read and write processing.

On the other hand, when the PDL data decompression processing speed in the rendering unit 4 is slower than the printing speed of the color printer 13, the same processing as the decompression processing to the compression memory 10 using the sub-closed path 15 is performed. ,
After decompressing the PDL data for one page, the lossless decompression unit 11 decompresses and prints the compressed data stored in the compression memory 10, so that the processing speed in the rendering unit 4 becomes the processing speed in the color printer 13. It is possible to print even if it cannot catch up.

An example of such a printing process for one page is shown in the flowchart of FIG.
The data is received, expanded by the rendering unit 4, expanded in the band buffer 5, and stored (step S22).
In step S23, it is determined whether or not the development speed in the rendering unit 4 is faster than a predetermined speed (speed corresponding to the print speed of the printer 13), and if it is higher, the process proceeds to step S24 and the memory management unit 6 causes the band buffer 5 is read in band units, and the printer processing unit 1 is passed through the real-time through path 16 in step S25.
2 and the image data is output to the color printer 13. Such processing is executed until the printing of one page is completed.

On the other hand, when the decompression speed in the rendering unit 4 is slower than the predetermined speed in step S23, the process proceeds to step S28, the data is read from the band buffer 5, compressed by the lossless / lossy compression unit 7 and stored in the compression memory 10. Remember. In step S30, it is checked whether or not the compression of the image data for one page is completed. If not, the process returns to step S28 to execute the above-mentioned processing. When one page of compressed data is stored in the compression memory 10 in this way, the process proceeds to step S31, and the lossless decompression unit 11 decompresses the compressed data and outputs the decompressed data to the printer processing unit 12. Then, from the processing unit 12 to the color printer 13
Is output to and printed. As described above, when the rendering process in the rendering unit 4 does not catch up with the print speed, the data transfer via the real-time through path 16 is not performed.

Supplementally, there is another case where the data is sent to the compression and decompression section and the real-time through path 16 is not used. As described above, a plurality of PDL data from the host computer 1 cannot be received at one time. It is at the time of sub-close, which is received by dividing into times. However, even in this sub-close, if there is a margin in the expansion time at the time of expanding the final PDL data to be received after being divided, the rendering unit 4 may be added to the image data expanded by the lossless expansion unit 11 in the band buffer 5. The image data obtained by expanding the last PDL data expanded by is expanded, and the expanded image data (image data corresponding to the last PDL data block) is directly passed through the compression / expansion unit.
It is also possible to output to the color printer 13 via the printer processing unit 12 via the real-time through path 16. By doing so, the time from the reception of the last PDL data to the start of printing can be shortened.

The flow chart of FIG. 4 explains this processing.

In step S41, the PDL data development processing via the sub-closed path 15 described with reference to the flow chart of FIG. 2 is performed, and in step S42, the final PDL data block is received until step S42.
41 and S42 are repeatedly executed.

When the final PDL block is received, the process proceeds to step S43, and the compressed data up to the immediately preceding PDL block stored in the compression memory 10 is decompressed and output to the printer processing unit 12. With this, the final PD
The L block data is expanded by the rendering unit 4 and output to the printer processing unit 12 via the real-time through path 16. As a result, the data from the lossless decompression unit 11 and the data received via the real-time through path 16 are combined and output to the color printer 13 as one-page print data for printing.

Next, the order of rendering performed by the rendering unit 4, which is a feature of this embodiment, will be described.

Generally, when outputting to the color printer 13 via the real-time through path 16, the rendering order of the rendering unit 4 is such that, when outputting to the color printer 13 in the color-sequential frame-sequential method, each band is assigned to each color. A frame-sequential method is adopted in which the development is sequentially performed, and after the development of one surface is completed, the development of the next color surface is started.

Therefore, when the print data is output through the compression / expansion unit, and when the real-time through path 16 is used.
The order of the display list to be expanded by the rendering unit 4 is different from that when the print data is output through. Also, the final P when using the sub-closed path 15
Needless to say, when developing DL data, the same developing order as when outputting to the color printer 13 via the real-time through path 16 is required.

Next, details of the lossless / lossy compression method, which is a major feature of the embodiment of the present invention, will be described.

FIG. 5 is a block diagram showing the configuration of the lossless / lossy compression unit 7 of this embodiment.

The lossless / lossy compression unit 7 has a two-stage structure internally, and the preceding stage has a data amount conversion unit 8
And the latter stage is the lossless compression unit 9. In general, the lossless compression unit 9 uses variable length compression in the present embodiment, and the amount of generated data after compression cannot be manipulated. Therefore, in order not to overflow the capacity of the compression memory 10,
It is necessary to control the amount of data before compression. Therefore, after the data amount conversion unit 8 controls the data amount before compression by the lossless compression unit 9, the generated code amount control is realized by losslessly compressing the image data with the reduced data amount.

In this embodiment, it is assumed that print data having a resolution of 600 dpi is output to the color printer 13. Band buffer 5 has 2 (bits / pixel)
The image data that has been quaternized by the quaternary dither of is expanded. When this image data is losslessly compressed and stored in the compression memory 10 (lossless compression), if the memory capacity overflows, The amount conversion unit 8 converts the image data into 1 (bit / pixel) at 600 dpi, reduces the total amount of image data to about half, and then compresses it with the lossless compression unit 9 (first lossy compression). . By performing such switching, the image data expanded at a desired compression rate can be compressed, and the used capacity of the compression memory 10 can be controlled.

If a sufficient compression ratio cannot be obtained even by the first lossy compression, the data amount conversion unit 8 outputs 6
The image data is not 1-bit (/ pixel) data at 00 dpi, and the resolution of the image data is 3 in either the main scanning direction (horizontal direction) or the sub-scanning direction (vertical direction).
Sub-sampled to 00 dpi, for example, main scan 300 dpi
i, sub-scanning 600 dpi, 1-bit (/ pixel) image data is converted. With this method, the compression rate can be further reduced to 1/2 of the lossy compression (second lossy compression). Furthermore, if the third to Nth lossy compressions having a higher compression rate than the second lossy compression are provided, finer control of the code amount can be performed.

Therefore, according to the above lossy compression method, a lossy compression rate of about 1/2 to 1 / n can be achieved as a whole even if the lossless compression unit 9 can hardly perform compression. As a result, the capacity of the compression memory 10 may be about 1/2 to 1 / n of the uncompressed data amount.

[Other Embodiments] In this other embodiment, in order to prevent data from being written beyond the capacity of the compression memory 10, lossy compression is performed to suppress an increase in the amount of compressed data. Another embodiment will be described.

Normally, the lossless compression is performed as in the first embodiment.

When this compression causes the amount of compressed data to exceed the capacity of the compression memory 10, or when it is expected that the amount of compressed data will exceed the capacity of the compression memory 10 before compression. In this case, the four-valued dither processing executed at the final stage of the rendering unit 4 is switched to the two-valued dither processing. As a result, the rendering unit 4 is 600 dp
An image of 1 (bit / pixel) with i (dots / inch) is developed in the band buffer 5. As a result, the data capacity becomes about 1/2 of that in the case of quaternization, and the data amount conversion unit 8 is used in an unnecessary state or a through state. Still further, when the amount of compressed data exceeds the capacity of the compression memory 10, the rendering unit 4 reduces the resolution of at least one of the main scanning direction and the sub scanning direction to 300 dpi (half resolution). The 1-bit output binarized dither processing may be performed on the image data having the reduced resolution.

As a result, the volume of compressed data is
At least about 1/4 of the capacity of the received data can be achieved, and the compression rate of the image data that does not exceed the capacity of the compression memory 10 can be achieved. In addition, at the time when the capacity of the compressed data exceeds the capacity of the compression memory 10 in the normal operation such as the 3 (bit / pixel) ternarization processing at 600 dpi described above, or P
Before decompressing the DL data, the decompression data capacity of the rendering unit 4 is reduced to 1/2 or 1/4 by predicting the compression rate of the image data from the characteristics of the received image data.
You may decide whether or not to.

By the way, when it is judged that the re-rendering is necessary again after expanding the PDL of the image data, the received PDL data is left in the memory 3 even after the expansion of the PDL data, and only the display list is displayed. Can be erased to provide a margin in the memory capacity of the memory 3.

As described above, according to the present embodiment, the compression rate by the lossless compression is insufficient and the compression memory 1
When the capacity of 0 is exceeded, the gradation or resolution of the image data is reduced and then lossy compression is performed so that a sufficient compression rate can be obtained. However, if it is judged whether or not the compression ratio is appropriate based on whether or not the amount of compressed data exceeds the memory capacity of the compression memory 10, it is possible to judge in units of one page of compressed data, and to perform the same lossy compression in units of one page. I can do it. The compression ratio may be determined for each band, or for each color component forming one band, and the 1st to Nth lossy compression and lossless compression may be switched for each band. Furthermore, if you look closely, you can always monitor the amount of compressed data,
By switching between lossy and lossless compression, finer control of the code amount can be performed.

Although not described in the above embodiment, when the reduction of the data capacity for the third to Nth lossy compression is reduced to ⅛ or 1/16, for example, 60
2 (bit / pixel) image data at 0 dpi, 300
If it is converted to image data of 1 (bit / pixel) in dpi, compression of about 1/8 can be achieved, and further, if the resolution of either main scanning or sub scanning is set to 150 dpi, compression of 1/16 is also achieved. Can be achieved.

In order to make the data capacity 1/4,
2 (bit / pixel) at 300 dpi in the data amount conversion unit 8
Image data and the rendering unit 3
It may be considered that the image data is expanded to 2 (bit / pixel) at 00 dpi (rendering unit 4).

Even if the present invention is applied to a system composed of a plurality of devices (for example, host computer, interface device, reader, printer, etc.), a device composed of one device (for example, a copying machine, a facsimile). Device).

Another object of the present invention is to supply a system or apparatus with a storage medium recording a program code of software for implementing the functions of the above-described embodiments.
Computer of the system or device (or CP
(U or MPU) also reads and executes the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R, magnetic tape, non-volatile memory card, ROM, etc. can be used.

Further, not only the functions of the above-described embodiments are realized by executing the program code read by the computer, but also the OS (operating system) running on the computer based on the instructions of the program code. ) And the like perform some or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written in the memory provided in the function expansion board inserted into the computer or the function expansion unit connected to the computer, based on the instruction of the program code, , The CPU included in the function expansion board or function expansion unit performs a part or all of the actual processing,
The case where the functions of the above-described embodiments are realized by the processing is also included.

As described above, according to the present embodiment, the gradation or resolution of the image data is lowered in multiple stages, and then the image data is compressed, so that the image is compressed with a minimum deterioration in image quality. The volume of image data can be suppressed within a predetermined range.

When rendering is performed, the order can be performed in band or color order, and there are two paths, a path for performing compression processing and a real-time through path for directly outputting without compression / decompression. As a result, it is possible to efficiently print by minimizing the time required for the printer to start printing.

[0065] According to the present invention described above, 1 Bae
Received PDL data for multiple pages
When expanding and printing with a specified method,
Exhibition of PDL data using Mori and Sub Close Path
Since it is opened, the image developed while suppressing image quality deterioration
Data can be efficiently stored in a compressed state. Also the last
When a PDL data block is received, the immediately preceding PDL
While decompressing the data and outputting it to the printing means,
Only the image data corresponding to the last PDL data block
Via the real-time through path without going through the compression / decompression section
Directly output to the printing means by using the
Can be done.

Further, according to the present invention, further, lossless / lockable
The amount of codes can be controlled by changing the sea compression.

[0067]

[0068]

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a printing system according to an embodiment.

FIG. 2 is a flowchart showing processing of print data using a sub-closed path in the controller of the present embodiment.

FIG. 3 is a flowchart showing print data processing based on the relationship between the rendering processing in the controller and the print speed in the printer according to the present embodiment.

FIG. 4 is a final PD in the controller according to the present embodiment
It is a flowchart which shows the process which outputs L block via a real-time path.

FIG. 5 is a block diagram showing a configuration of a lossless / lossy compression unit in the controller of the present embodiment.

[Explanation of symbols]

1 Host computer 2 CPU 2a memory 3 memory 4 Rendering section 5 band buffer 6 Memory management unit 7 Lossless / Lossy Compressor 8 Data amount converter 9 Lossless compression section 10 compression memory 11 Lossless extension 12 Printer processing unit 13 color printer 14 Controller 15 sub-closed path 16 Real Time Through Pass

─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Ken Onodera 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference JP-A-7-231391 (JP, A) JP-A-4 -323060 (JP, A) JP 5-346776 (JP, A) JP 7-266633 (JP, A) JP 8-289107 (JP, A) (58) Fields investigated (Int.Cl) . ⁷ , DB name) G06F 3/12 B41J 5/30 H04N 1/41

Claims (4)

(57) [Claims] 1. The PDL data for one page is divided into a plurality of times.
Receiving means to divide and receive, The PDL data received by the receiving means is expanded and the image data is
Deployment means to obtain data, A first memory for storing the image data obtained by the expanding means
Means and A pressure for compressing the image data stored in the first storage means.
Reduction means, Second storage for storing the compressed data obtained by the compression means
Means and A decompression for decompressing the compressed data stored in the second storage means.
Long way, The decompressed data obtained by the decompressing unit is transferred to a predetermined printing unit or
Means for outputting to the first storage means, The PDL data received by the receiving means is transmitted a plurality of times.
Depending on how many times it is,
Control means for controlling the work, Equipped with The control means is For the first reception by the receiving means,
The received PDL data is expanded by the expansion means.
The image data obtained by the expansion in the first storage means.
The image data stored is stored by the compression means.
The compressed data obtained by the compression
I control it to be stored in a memory, From the second time by the receiving means to the last time before the last time
In reception, the number of times stored in the second storage means
The compressed data obtained by reception before reception of
And the decompression data obtained by the decompression
Output by the force means to the first storage means.
Long data is stored in the first storage means and received at that time
The PDL data is expanded by the expanding means,
Image data obtained by the expansion is stored in the first storage means.
The already-expanded data is overwritten and stored, and the overwritten storage is performed.
The image data obtained later is compressed by the compression means.
The compressed data obtained by the compression in the second storage means.
Control it to remember, In the final reception by the receiving means, the second
Obtained by the reception before the current reception stored in the storage means
Decompressed compressed data by the decompression means , In the extension
The obtained decompressed data is output to the predetermined printing device by the output means.
Output to the stage and expand the PDL data received at that time.
The image data obtained by the expansion is performed by the expansion means.
Data in the first storage means and stored in the first storage means.
The stored image data is passed through the compression means and the expansion means.
Control to output to the specified printing means without
A characteristic output control device. 2. The lossless pressure is applied by the compression means.
It is possible to perform compression and lossy compression selectively.
The output control device according to claim 1, which is a characteristic. 3. The PDL data for one page is divided into a plurality of times.
The receiving process of dividing and receiving, The PDL data received in the receiving step is expanded to generate an image data.
Deployment process to deploy to the data, Compressing step of compressing the image data to obtain compressed data
When, Decompression step of decompressing the compressed data to obtain decompressed data
When, The decompressed data is stored in a predetermined printing unit or the first memory.
Output process to output, The PDL data received in the receiving step is stored in the plurality of times.
Depending on how many times it is, execute each of the above steps.
A control process for controlling, Have The control step is For the first reception by the reception process,
The received PDL data is expanded by the expansion process
The image data obtained by the expansion is recorded in the first memory.
The stored image data is compressed by the compression process.
And compress the compressed data obtained by the compression to the second memory.
Control to remember Each from the second time to the last time by the receiving process
In reception, the number of times stored in the second memory is stored.
Compressed data obtained before reception to the decompression step
Further decompression, decompression data obtained by the decompression is output as the above.
The decompression data is output by outputting to the first memory in a process.
Data stored in the first memory and received P
The DL data is expanded by the expansion process, and the expansion is performed.
Before the image data obtained in step 1 has been stored in the first memory
Overwrite the decompressed data , Obtained after overwriting memory
Image data to be compressed by the compression process,
To store the compressed data obtained in step 2 in the second memory
Control and In the final reception by the reception step, the second
Obtained by the reception before the current reception stored in the memory
The compressed data is expanded by the expansion step and obtained by the expansion.
The decompressed data by the output step by the predetermined printing means.
And output the PDL data received at that time.
Image data obtained by the expansion process performed by the expansion process
Is stored in the first memory and stored in the first memory.
Image data without going through the compression and decompression steps.
It is characterized by controlling to output to a predetermined printing means.
Output control method. 4. The compression in the compression step is a lossless pressure.
It is possible to perform compression and lossy compression selectively.
The output control method according to claim 3, wherein the output control method is a characteristic.