JP3459740B2 - Print control apparatus and method and printing apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing control apparatus and method capable of interpreting a printer language, and a printing apparatus.

[0002]

2. Description of the Related Art Generally, on a host computer, documents created by various applications (including not only sentences but also figures and images) are connected by a device driver program called a printer driver operating on the host computer. It is translated into a language that can be interpreted by the printer (currently, most of the time, it is translated into page description language = PDL) and is output to the printer via a communication cable or the like.

The printer has a controller for controlling the entire printer and a printer engine for actual printing. The controller receives data, interprets PDL, and creates print image data. Pass to the printer engine through the engine interface.

There are several types of printer engines for interpreting and printing a page description language. Among them, the one adopting the electrophotographic method has problems of speed, print quality, and noise. Widely used because of its advantages.

Further, as an electrophotographic printer engine, an LED system, a laser beam system and the like are known. In any case, a double buffer is usually provided in the interface portion for transferring to the engine or in the vicinity thereof. One is used for writing image data, the other is used for output to the printer (for shipping),
This is switched alternately.

By the way, with the recent development of technology, the resolution of the engine is only getting higher, and it is possible to express the gradation in a pseudo manner by using the dither method or the error diffusion method.

[0007]

In the above printer, a huge memory is required to reproduce high resolution and high gradation.

Therefore, in order to save the amount of memory for one page, if the printer engine is for binary recording, the multi-valued image data based on the sent PDL data is used each time for the dither method. It may be possible to perform binarization by using, for example. However, when command data intended for multi-valued data of PDL data is received with a delay, multi-valued operations such as logic synthesis cannot be performed on an already binarized image.

Supplementally, even if the binary compression is performed once and then expanded again, the data is no longer binary image data, so that the PDL data received later is intended to be multi-valued data, and Is intended to perform a logical operation on an image based on the conventional PDL data (for example, to obtain a watermark effect), a normal logical operation cannot be expected, and a print result does not become as intended.

On the other hand, as another method known as a device for suppressing the memory capacity, printing in band units can be mentioned.

This is for processing one page by dividing it into several bands. For example, if a buffer for two bands is provided, the image data is transferred to one of the band buffers for transfer. In the middle, the image data of the next band may be expanded in the other band buffer, and by alternately processing this, printing for one page can be realized.

However, the electrophotographic printer engine, by its nature, cannot start printing once it has started, until it has finished processing for that page.

Therefore, in some cases, even when it is time to send the image data in a certain band buffer to the printer engine, a situation may occur in which the image data expansion processing for that band is not completed. . This is a problem that often occurs when printing a complicated image.

Further, in the print processing for each band, if the image data of a certain band is transferred to the printer engine, the band buffer will be opened for developing the image data of the next band. It is no longer possible to deal with PDL data received late.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a printing control apparatus and method, and a printing apparatus that enable a printing unit to perform normal printing as intended. Is.

[0016]

In order to solve this problem, for example, a print control apparatus of the present invention has the following configuration. That is, a generation means for generating image data by interpreting input data described in a predetermined description language, a first compression / expansion means for M-value compression and M-value expansion of the image data, and Second compression / expansion means for performing N-value compression and expansion of the image data expanded by the M-value by the first compression / expansion means, and image data expanded by the N-value by the second compression / expansion means are printed in a predetermined manner. Output means for outputting to the means.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of an embodiment according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a sectional structure of a printer device according to the embodiment. In the figure, reference numeral 700 denotes a printer control unit which receives print data from a host computer, generates image data, and outputs the image data to a printer engine (details will be described later).

A scanner 711 is a laser output unit (not shown) for converting an image signal (video signal based on image data) from the printer control unit 700 into an optical signal, a polygon mirror 712 having a polyhedron (for example, octahedron), It has a motor (not shown) for rotating the mirror 712, an f / θ lens (imaging lens) 713, and the like. Reference numeral 714 is a reflection mirror that changes the optical path of the laser light, and 715 is a photosensitive drum. The laser light emitted from the laser output portion is reflected by one side surface of the polygon mirror 712, and the f / θ lens 71
The surface of the photosensitive drum 715 rotating in the direction of the arrow in the drawing is linearly scanned (raster scan) via the mirror 3 and the mirror 714. As a result, an electrostatic latent image corresponding to the printed image is formed on the surface of the photosensitive drum 715.

Further, 717 is a primary charger, 718 is a whole surface exposure lamp, 723 is a cleaner part for collecting the untransferred residual toner, 724 is a pre-transfer charger, and these members are arranged around the photosensitive drum 715. It is arranged.

Reference numeral 726 denotes a developing device unit which develops the electrostatic latent image formed on the surface of the photosensitive drum 715 by laser exposure, and has a structure shown below. 731Y, 7
31M, 731C and 731Bk are developing sleeves 730Y and 730 that are in contact with the photosensitive drum 715 and perform direct development.
M, 730C and 730Bk are toner hoppers for holding the preliminary toner, 732 is a screw for transferring the developer, and these sleeves 731Y to 731B.
k, toner hoppers 730Y to 730Bk, and a screw 732, which are disposed around the rotation axis P of the developing device unit. In addition, the symbols Y, M, and
C and Bk indicate colors. That is, "Y" is yellow, "M" is magenta, "C" is cyan, and "Bk" is black. When forming a yellow toner image,
The yellow toner developing process is performed at the position shown in this figure. Also,
When forming a magenta toner image, the developing unit 7
26 is rotated about the axis P in the drawing so that the developing sleeve 731M in the magenta developing unit contacts the photoconductor 715. Cyan and black development work similarly.

Reference numeral 716 is a transfer drum that winds the paper and transfers the toner image formed on the photosensitive drum 715 to the paper, 719 is an actuator plate for detecting the moving position of the transfer drum 716, and 720 is this. When the transfer drum 7 is brought close to the actuator plate 719,
A position sensor for detecting that 16 has moved to the home position, 725 for a transfer drum cleaner, and 727.
Is a paper pressing roller, 728 is a slow charger, and 729 is a transfer charger. These members 719, 720, 725, 72
7, 729 are arranged around the transfer roller 716.

On the other hand, reference numerals 735 and 736 denote paper feed cassettes for accommodating paper sheets (paper sheets). In the embodiment, the paper feed cassette 7 is used.
35 includes, for example, A4 size paper and a paper feed cassette 736.
It is assumed that A3 size paper is stored in. 7
37 and 738 are paper feed rollers for feeding paper from cassettes 735 and 736, and 739, 740, and 741 are timing rollers for timing of paper feed and conveyance. The leading end is guided by the guide 749 and wound around the transfer drum 716 while being held by the gripper described later, and the process proceeds to the image forming process. It should be noted that which of the paper feed cassettes 735 and 736 is selected is determined by an instruction from the main control unit 31, and only the selected paper feed roller is rotated.

550 is a drum rotation motor,
The photosensitive drum 715 and the transfer drum 716 are synchronously rotated.
750 is a peeling claw 742 for removing the sheet stuck by the action of static electricity from the transfer drum 716 after the image forming process is completed.
Is a conveyance belt for conveying the detached paper, 743 is an image fixing unit for fixing the paper conveyed by the conveyance belt 742, and the image fixing unit 743 is a pair of thermal pressure rollers 7.
44 and 745.

The printer control unit 700 having the above-mentioned configuration
FIG. 2 shows the relationship between the schematic configuration of the printer and the printer engine unit that performs the above printing.

The outline of the operation will be described below with reference to FIG.

The CPU 200 controls the constituent elements of the apparatus according to the program in the memory 201. The printing procedure is as follows.

When the CPU 200 receives the PDL data from the host computer via the communication section 202, the CPU 200 stores it in the reception buffer in the memory 201, and the renderer 20
3 converts the data into a format that is easy to process, that is, intermediate code (hereinafter, a series of intermediate code is referred to as a display list).

The renderer 203 renders according to this display list based on the operating conditions set by the CPU 200, and multi-value image data according to PDL in the band buffer 204 (here, 8 bits (256 values) for each RGB component). Image data) is developed.

When the expansion for one band is completed, the multivalued image data is a JPEG section 20 which is a kind of multivalued compression.
5, and performs JPEG compression in band units.

Specifically, the JPEG compression unit 206 performs known JPEG compression, but in order to increase the compression rate, RG
Convert the B format data to Yuv format once, and convert it to JP
It is EG compressed and stored in the memory 207.

By performing the above operation for all bands, the JPEG compressed data of one page of band image is stored in the memory 207.

In the above processing, if the PDL data cannot be stored for one page at a time and the PDL data for one page must be divided into several times for memory storage and band expansion, the first time. After the above JPEG compression is once performed using the stored PDL data, the CPU2
00 causes the JPEG decompression unit 208 to read the JPEG-compressed band image from the memory 207, decompresses it, further converts it to RGB, and expands it again in the band buffer 204 (from the JPEG decompression unit shown in the figure). Sub-close back to band buffer). This allows
Prepare to combine the remaining PDL data with the expanded image.

In the above description, RGB → Yuv
The conversion, JPEG compression, decompression, and Yuv → RGB conversion processing are known per se, and thus detailed description thereof is omitted here.

After that, a newly created display list is created by using the remaining PDL data newly received and stored from the computer, and the synthesizing process is performed on the multi-valued image developed in the band buffer 204 by the above process. . In this case, since the image represented by the display list is multivalued and the image expanded and expanded is also multivalued, the logical operation is as originally intended.

In the above sense, the renderer 203
In a certain process, the data in the band buffer 204 can be read, a logical operation with the image data to be processed can be performed, and then the data can be written in the band buffer 204 again.

Finally, P indicating the end (page break command) for the page from the host computer
Receive DL data. When the CPU 200 receives this code, it can confirm that the PDL data for the page currently being processed will not be received thereafter, so that the processing such as expansion of the unprocessed display list is terminated. Wait for JPEG decompression unit 2
08, the image data of each band for one screen, which has been JPEG compressed, is sequentially expanded, and the multi-valued image data of each band obtained as a result is sequentially processed by the image processing unit 2.
09 to send.

The image processing unit 209 receives multi-valued image data (in RGB format), performs YMC format, and further performs known UCR processing to generate YMC and K components. Then, processing matching the characteristics of the printer engine 214 is performed for each color component. For example, resolution conversion is one of them, and dither processing and error diffusion processing are also performed.

If the printer engine unit can reproduce the N gradation image based on the N value data, the image processing unit 209
Also performs the N-value conversion process.

The JBIG unit 210 is thus the image processing unit 2.
09, the data received is subjected to JBIG processing which is one of the well-known binary compression processing.

For example, when the image processing unit 209 performs ternary or quaternary conversion, it is sufficient to allocate 2 bits to each pixel, so compression is performed on a plane composed of 1 bit and another 1 bit is used. Similarly, compression may be applied to a plane composed of. Further, in the case of 5 to 8 value conversion, it is sufficient to have 3 bits for each pixel, and therefore it is sufficient to process for 3 planes.

The JBIG compression unit 211 performs the above processing, and stores the JBIG compression data in band units for each color component in the memory 212.

By repeating this, all the bands constituting one page are binary-compressed in the memory 212.

Further, since the processing so far is not restricted by the output speed of the printer engine, the JPEG unit 20
5. The JBIG unit 210 is not affected by the cost increase for speeding up.

When outputting to the printer engine 214,
The CPU 200 controls the JBIG decompression unit 213, sequentially reads the JBIG compressed data for each color component from the memory in accordance with the operation timing of the printer engine 214, decompresses it, and generates N-valued data, which is then sent to the printer engine 214. Output. This decompression processing can be performed at a speed sufficiently high for the operation of the printer engine 14.

There is actually an interface between the JBIG decompression unit 213 and the printer engine 214, and the interface has, for example, two or more buffers that are alternately switched as described above, and an N value. A circuit for generating a video signal by performing pulse width modulation based on the encoded data is provided.

In the above description, the memory 20
1, band buffer 204, memory 207, memory 21
It is desirable to use a memory that can be commonly used for the two.

The reason is that, for example, when the received PDL data is converted into an intermediate code (display list),
The area storing the converted PDL data can be released and used for other processing. If the band image is expanded in the band buffer based on the display list and then the band image is JPEG-compressed, the storage area of the display list for the band can be released.
This is because the same applies when converting EG data to JBIG data.

In particular, the information when decompressing JPEG-compressed data is 8 bits for each RGB component (total of 24 bits).
Bit), even if the image processing unit 9 consumes a memory for several lines by dithering or error diffusion processing,
For example, in the case of binarization, each bit of YMCK (total 4 bits) is sufficient, and even in the case of quaternization, each pixel needs only 2 bits (total 8 bits). Therefore, the memory capacity required for storing by JPEG compression. If there is + α (memory capacity used in the image processing unit), the JBIG processing can be performed within that memory capacity, and the memory capacity will not run out.

For the above reasons, if each memory (including the band buffer) shown in FIG. 2 is a common memory,
When viewed as the entire memory, if one type of information is large, another type of information is reduced, and it becomes possible to effectively use a limited amount of memory for appropriate image processing.

FIG. 3 shows a specific block configuration of the printer controller of the embodiment.

In the figure, reference numeral 2 is a ROM that stores the operation processing procedure (program) of the CPU 200, font data, and the like. Reference numeral 3 is an operation panel for giving various instructions to the apparatus and displaying a status, and 4 is an interface functioning as the communication unit 202 in FIG. Reference numeral 5 denotes a RAM, which is used as a work area for the CPU 200, and also includes the memories 201, 207 in FIG.
212 and the band buffer 204.

Reference numeral 6 denotes an engine interface. One is internally output to the printer engine, and the other is used for decompressing and writing the JBIG format compressed data in the RAM 5, and this operation is also performed. 1
It has a buffer that switches for each scanning line. Further, as described above, the PWM processing circuit is also included (when the printer engine can record with three or more values).

Now, the RAM 5 in the above-mentioned configuration is as shown in FIG.
Therefore, as shown in the figure, a reception buffer, an intermediate buffer (area for storing a display list), a band buffer, a JPEG buffer for storing JPEG compressed data, It has a JBIG buffer. The size of each of these is dynamically changed, and as shown in the figure, the area is not divided by boundary addresses.

Further, in the configuration of FIG. 3, the CPU 20
0 is the JPEG unit 205 and the JBIG unit 21 in FIG.
It functions as 0. That is, the CPU 200 performs the functions of the renderer 203, the JPEG unit 205, and the JBIG unit 210.

The operation processing procedure of the CPU 200 will be described below with reference to the flow charts shown in FIGS. In addition,
It is assumed that the procedure of storing the data received via the interface 4 in the reception buffer in the RAM 5 and interpreting the data to create the display list in the intermediate buffer is performed by another task. Here, the renderer 203, JP
The processing of the EG unit 205 and the JBIG unit 210 will be mainly described.

First, in step S1, one band of multi-value color band image is created in the band buffer according to the display list in the intermediate buffer of the RAM 5.

When the creation of this band image is completed,
The process proceeds to step S2, and the corresponding J in the RAM 5
A buffer for PEG compression is secured, and the process proceeds to step S3 where the image data expanded in the band buffer is JPEed.
G compression is performed and the JPEG secured in step S4
Store in buffer.

In step S5, JP for all bands is set.
It is determined whether or not EG compression has been performed, and if not, step S
The process returns to 1 and the above process is repeated.

When the JPEG compressed data for all bands are created and stored, the process proceeds to step S6, and it is determined whether or not there is an unprocessed display list in the intermediate buffer. In addition, although the description goes back and forth, in the band expansion process in step S1, the processed display list is opened so that data can be sequentially stored.

When it is determined that there is an unprocessed display list, the process proceeds to step S7, the JPEG data of the band shown in the display list is taken out, and it is expanded in the band buffer in step S8. Then, the process returns to step S1.

In step S1, the unprocessed display list is processed. At this time, the previously developed band image is developed in the band buffer, and the same format data (multi-valued color data) is used. Therefore, the logic synthesis processing and the like can be normally performed.

As described above, when there is no unprocessed data, that is, when the intermediate code corresponding to a page break is at the end, the processing for the entire page of interest is completed in a true sense. Therefore, the process proceeds from step S6 to step S9.

In step S9, one band data stored in the JPEG buffer is taken out and decompressed. Then, the process proceeds to step S10, and the extracted area in the original JPEG buffer is released for use in other processing, and the quantization processing is performed. It should be noted that this quantization processing is performed by N-value conversion based on the specifications of the printer engine.
The process of converting to K is also performed.

Then, a memory for storing JBIG compressed data, which is a binary compression process, is secured for the quantized data (step S12).
The compression process is performed (step S13), and the compressed data is stored in the secured area (step S14).

In step S15, it is determined whether or not the processing for all the bands is completed. If not, step S15
Returning to step 9, the above process is repeated.

When the JBIG compression of all bands is completed in this way, the printer engine is activated to start the conveyance of the recording medium (recording paper etc.), and the JBIG compressed band data is sequentially recorded for each recording color component. The decompressed data is output in real time to the one set as the writing buffer in the engine interface 6 to record an image. When the recording process for one page is completed,
The JBIG compressed data for one page is no longer needed, so that area is released.

The recording medium is conveyed from the cassette,
Since there is some time before it is wound on the transfer drum and actually transferred, it is recommended to start the transport while the JBIG compression process is being performed on an appropriate band (for example, the last band). Is also good. In this case, it is possible to save the time until the transfer is started and the transfer is started, and as a result, the recording speed can be increased.

Even when the JBIG buffer is released, the JBIG buffer may be released each time the recording process is completed in the order of the color component areas. As a result, the memory can be used more effectively.

When JBIG compressed data is created from JPEG compressed data, the amount of information is basically reduced, so that the free space of the memory is increased and the capacity of the reception buffer and the intermediate buffer can be increased, and the print data of the next page can be increased. Since the number of print jobs can be increased, the host computer can be released from the printing process faster. However, if the number of receive buffers and intermediate buffers is increased, the data for multiple pages can be stored as a result, and instead, the JPEG buffer (JPE
If the G buffer is secured, the JBIG buffer is secured, which may be understood because the latter has a small amount of information.) It may not be possible to secure a sufficient area. It is desirable to set the capacity in advance so that at least the JPEG buffer is not hindered.

As described above, according to the present embodiment, the multi-valued compression / expansion circuit only needs to operate at a speed sufficiently commensurate with the speed at which the PDL data is expanded. Become. Further, it is possible to expand again and perform logic synthesis. In addition, the second-stage compression for supplying data to the printer can be the longest, inexpensive binary compression, and the cost can be reduced. Supplementally, the internal DCT operation circuit occupies the majority in the multi-valued JPEG compression, and usually a parallel circuit configuration is adopted for speeding up. For example,
If the operating speed is reduced to 1/10, the DCT portion will also be reduced to about 1/10 and the overall compression cost will be 1/3 to 1/5. Further, since the image processing by the image processing unit 209 can be performed at a relatively low speed, the cost can be reduced.

As described above, according to this embodiment,
When controlling an engine that forms an image in band units, multilevel image data is compressed in band units on the basis of PDL data so that PDL data received later can be obtained.
The data can be processed normally. In addition, at the actual printing stage, rendering is not performed and simple decompression processing is performed for each band, so that there is no possibility that the band image will not be output in time.

Furthermore, the memory required for each process is made common, and the data that has been processed by each process is positively released, and the area required for each process is dynamically secured. It is possible to effectively use a small amount of memory as compared with the case where the memory is scattered.

<Second Embodiment> In the above-described embodiment (first embodiment), the received PDL data is first stored in the reception buffer, converted as a display list, and then expanded into a band buffer by the renderer. Was done.

However, in general, the PDL data includes image data in addition to the drawing command (including the character code).

The image data generally has a large amount of information, although it depends on the size and the number of gradations for each color.

Therefore, if image data is included in the received data, it is temporarily stored in the receive buffer.
Immediately and directly, the data may be transferred to the band buffer to perform the above JPEG compression. At this time, when it is time to perform processing on the generated display list, the image of the corresponding band buffer is re-developed in the band buffer in the sub-close, so that the processing speed as well as the memory capacity is reduced. Don't worry about the restrictions.

Also in the second embodiment, it is the same as that described in the first embodiment in that it is desirable to use one common memory for each memory and band buffer.

<Third Embodiment> In the third embodiment, as shown in FIG. 6, a through path is directly provided from the band buffer 204 to the image processing unit 209. This is to cope with the case where the sub-close does not occur as described above.

When the sub-close occurs,
This may occur when PDL data corresponding to a page break cannot be received while receiving PDL data from the host computer and converting the PDL data into a display list, while performing the processing of FIGS. is there.

In other words, if it is certain that the page break command will be received early and will not be added later to the created display list, the JPEG section 205 is skipped, Band buffer 20
By directly passing the image data expanded in No. 4 to the image processing 209, the overall throughput (the number of print outputs per unit time) of the printing apparatus can be significantly improved.

When the processing speed of the renderer is equal to or higher than the printer speed when the sub-close is not generated, the switching may be made so that the JPEG portion and the JBIG portion are passed.

<Fourth Embodiment> Furthermore, even when it is known in advance that the host computer sends PDL data in the downward direction from the top band of one page, the through path of FIG. 6 can be utilized. .

In order to construct the PDL data so that the host computer side surely has such an order, the printer driver (a type of program) operating on the host computer can control the PDL data, so that the PDL data can be operated on the host computer. When printing is instructed by the application, the printer device is first notified of a command indicating that the PDL data can be transferred in the normal order. When this command is received, the control unit on the printer side sets to perform printing using the through path in FIG.
Do not intervene.

A general configuration of the host computer may be used, and therefore the configuration thereof will be omitted. However, the printer driver operating there may operate in accordance with the procedure shown in FIG. 7, for example.

The program corresponding to the flowchart shown in the figure is activated when a printing instruction is issued from an application running on the host computer.

First, before printing, the output P
A command indicating that the DL data is in the normal order is output (step S21).

Next, in step S22, the data to be printed is received from the application or OS, and the PDL data is created once in step S23. The created PDL data may be created in the RAM if there is sufficient free memory on the host computer, or may be created in a storage device such as a hard disk although the processing speed will be somewhat slower if there is no free memory.

After this, the PDL created in step S24
The data is rearranged and actually transferred to the printer device in step S25.

The processing on the printer device side turns on a flag to that effect in an appropriate area when the command indicating that the lines are arranged in the normal order is received, and skips the JPEG processing when this flag is turned on. It should be processed as follows.

As a result, the print throughput can be improved.

<Fifth Embodiment> Furthermore, the band buffer may be rendered in the CMCK format. In this case, the renderer 203 is multi-valued or 2
Although it is necessary to have a digitization function, the data capacity of the band buffer 204 is reduced.

Furthermore, when sub-close does not occur and rendering is sufficiently in time at the operation speed of the renderer 203, the expansion result of the band buffer 204 is JB.
It is also possible to connect to the outlet of the IG extension 213 and supply it directly to the LBP printer 13. In this case, the renderer 20
Reference numeral 4 needs to have a processing function such as binarization by sequentially rendering each color of C, M, Y and K according to the printer. In addition, the band buffer 20 has a double buffer configuration, and one of them performs rendering and the other performs shipping.

By providing the through path in this way, the throughput can be improved without the adverse effect of performing the compression even when the compression is not necessary.

Also, JBIG which is the binary compression in the present invention.
Although the compression is a lossless coding method, a lossy coding method or another inexpensive compression method, for example, Packbits compression or Lempel-Sive (LZ) compression method may be adopted. Further, the multi-valued JPEG compression / decompression unit can be replaced with another compression method capable of logical synthesis or the like, or a low-speed and low-cost compression method of software means, which is a printer speed-free method of the present invention. This is a technique that allows a two-stage compression configuration.

Further, by increasing the memory, it is possible to operate the circuits around the memory in parallel, for example, to start the rendering of the next page and perform the JPEG compression while the JPIG expansion is being performed and the throughput is reduced. It is also possible to contribute to the improvement of.

There is also a method in which the band expansion data is directly JBIG-compressed without using JPEG compression by using a through-pass at the time of the final sub-closing when the sub-closing occurs several times.

<Other Embodiments> In the above embodiments, the laser beam system is adopted as the printer engine, but the LED system may be used, for example. Further, an inkjet method or a thermal transfer method may be used. However, as is clear from the description of the above embodiment, it is desirable to apply the present invention when the engine for printing is high speed. In this sense, application to page printers is desirable.

Further, even when 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, copying machine, facsimile) Device).

In particular, in the case of the fourth embodiment, the present invention operates in cooperation with a program called a printer driver which operates on the host computer.
It is also achieved by supplying a storage medium recording the program code of software to a system or apparatus, and causing a computer (or CPU or MPU) of the system or apparatus to read and execute the program code stored in the storage medium. .

In this case, the program code itself read from the storage medium realizes the function of the above-described embodiment, 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.

Moreover, 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. It is needless to say that this also includes a case where the above) performs a part 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, It goes without saying that a case where the CPU or the like included in the function expansion board or the function expansion unit performs some or all of the actual processing and the processing realizes the functions of the above-described embodiments is also included.

As described above, according to the present embodiment, high-speed multi-value compression (expansion) operation is achieved by combining low-value binary compression with multi-value compression that enables logical synthesis even during sub-close. It eliminates the need and uses low-priced multi-level compression hardware or software to contribute to the reduction of the page buffer size and reduce costs. In addition, it is possible to use inexpensive binary caution and high-speed shipping, and to reduce costs by sharing a multi-valued memory area without adding memory for binary compression. Furthermore, multi-level compression can be used for object compression, and the frequency of occurrence of sub-close can be suppressed.

[0106]

As described above, according to the present invention, it is possible to perform normal printing as intended without depending on the printing speed of the printing means.

[0107]

[Brief description of drawings]

FIG. 1 is a diagram showing a cross-sectional structure of a printer device according to an embodiment.

FIG. 2 is a conceptual diagram of a device configuration when viewed as a procedure in the first embodiment.

FIG. 3 is a block configuration diagram of a control unit when the processing in FIG. 2 is implemented by software.

4 is a flowchart showing a processing procedure in the configuration of FIG.

5 is a flowchart showing a processing procedure in the configuration of FIG.

FIG. 6 is a conceptual diagram of a device configuration when viewed as a procedure in a third embodiment.

FIG. 7 is a flowchart of a processing procedure of a printer driver operating on a host computer according to the fourth embodiment.

[Explanation of symbols]

200 CPU 201 memory 202 Communication unit 203 Renderer 204 band buffer 205 JPEG section 206 JPEG compression unit 207 memory 208 JPEG decompression unit 209 Image processing unit 210 JBIG section 211 JBIG compression unit 212 memory 213 JBIG extension unit 214 printer engine

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Claims (25)

(57) [Claims] 1. A generation means for generating image data by interpreting input data described in a predetermined description language, and a first compression / expansion means for M value compression and M value expansion of the image data. A second compression / expansion means for performing N-value compression and expansion of the image data expanded by the M-value by the first compression / expansion means, and image data expanded by the N-value by the second compression / expansion means. A printing control device, comprising: an output unit that outputs to a predetermined printing unit. 2. An image processing means for performing image processing on the image data compressed and expanded by the first compression / expansion means before being compressed and expanded by the second compression / expansion means. The print control device according to claim 1. 3. The print control apparatus according to claim 2, wherein the M value and the N value have a relationship of M> N. 4. A generation step of generating image data by interpreting input data described in a predetermined description language, and a first compression / expansion step of M value compression and M value expansion of the image data. A second compression / expansion step of performing N-value compression and expansion of the image data expanded by the M value in the first compression / expansion step; and image data expanded by the N value in the second compression / expansion step. An output step of outputting to a predetermined printing means. 5. A print control device for receiving print data described in a page description language and interpreting the data, wherein the print control device generates image data for the received print data, and compresses the generated image data. A compression / expansion means for expanding the image data; an output means for converting the image data expanded by the compression / expansion means according to the characteristics of the printing means and outputting the image data to the printing means; A printing control apparatus comprising: a feedback unit for feeding back image data obtained by decompressing by the unit to the generation unit, and a control unit for controlling whether or not the feedback is performed. 6. The print control device according to claim 5, wherein the compression / expansion unit compresses and expands in band units. 7. The generating unit, the compression / expansion unit, and the output unit use a common predetermined memory as a work area, and dynamically secure and release the work area for processing. The print control device according to item 5. 8. The print control apparatus according to claim 5, wherein the generating unit generates multi-valued image data. 9. The output means outputs the multi-valued image data expanded by the compression / expansion means,
A conversion unit that converts the multi-valued image data into N-value data of a recording color component according to the characteristics of the printing unit, and a binary compression and expansion process for each bit plane of the converted N-valued data. 9. The print control apparatus according to claim 8, further comprising a binary system compression / expansion means for performing. 10. A determination means for determining whether or not the received print data is arranged in a normal order for each band, and the print data is arranged in a normal order for each band by the judgment means. The printing control apparatus according to claim 5, further comprising: a unit that passes the compression / expansion unit to the output unit when the determination is made. 11. The determining means determines that the bands are arranged in a normal order when it is determined that the print data for the page has already been prepared at the stage of compression by the compression / expansion means. The print control device according to claim 10, wherein the print control device is a print control device. 12. The determination means determines that the bands are arranged in a normal order when a predetermined command is received from a print data generation source before receiving the print data. The print control device according to claim 10. 13. The print control apparatus according to claim 5, wherein the printing unit is a laser beam printer. 14. The compressing / expanding means converts the RGB format image data based on the print data into the Yuv format once to perform JPEG compression, and when decompressing, restores the Yuv format data to the RGB format. The print control device according to claim 5. 15. A control method of an apparatus for receiving print data described in a page description language and interpreting the data, the generating step of generating image data for the received print data, and the generated image data. A compression / expansion step of compressing and expanding, an output step of converting the image data obtained by expansion in the compression / expansion step according to the characteristics of the printing means, and outputting the image data to the printing means, and the expansion step. 2. A printing control method comprising: a feedback step of feeding back the image data obtained by decompressing the image data to the generating step; and a control step of controlling whether or not the feedback is performed. 16. The print control method according to claim 15, wherein the compression / expansion step compresses and expands in band units. 17. The generation process, the compression / decompression process, and the output process use a common predetermined memory as a work area,
The printing control method according to claim 15, wherein the work area is dynamically secured and released for processing. 18. The print control method according to claim 15, wherein the generating step generates multi-valued image data. 19. The multi-valued image data expanded in the compression / expansion step in the output step,
A conversion step of converting the multi-valued image data into N-valued data of a recording color component according to the characteristics of the printing means, and a binary compression and decompression process for each bit plane of the converted N-valued data. 19. The print control method according to claim 18, further comprising a binary compression / expansion step for performing the above. 20. A determination step of determining whether or not the received print data is arranged in a normal order for each band, and the print data is arranged in a normal order for each band by the determination step. 16. The printing control method according to claim 15, further comprising a step of passing the compression / expansion step to the output step when the judgment is made. 21. The judgment step determines that the bands are arranged in a normal order when it is judged that the print data for the page has already been prepared at the compression step in the compression / expansion step. The printing control method according to claim 16, wherein the printing control method is performed. 22. The determining step determines that the bands are arranged in a normal order when a predetermined command is received from a print data generating source before the print data is received. 21. The print control method according to claim 20. 23. The printing control method according to claim 15, wherein the printing unit is a laser beam printer. 24. In the compression / expansion step, the image data in RGB format based on the print data is once converted into Yuv format and JPEG-compressed, and when decompressed, the Yuv format data is returned to RGB format. The printing control method according to claim 15. 25. A printing device which receives print data described in a page description language, interprets the data, and prints in band units, and generates multi-valued image data in band units for the received print data. Generating means, first compression / expansion means for compressing and expanding the generated multi-valued image data for each band, and multi-valued image data expanded by the first compression / expansion means for each band A second compression / expansion means for converting, compressing and expanding according to the characteristics of the printing means, and the second
Output means for outputting the image data expanded by the compression / expansion means to the printing means, and further feeding back the multi-valued image data expanded by the first compression / expansion means to the generation means. A printing apparatus comprising: feedback means and control means for controlling whether or not to perform the feedback.