JPH09244832A - Image processing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accelerate printing-out by storing compressed data outputted from a computer, extending these multi-level compressed data synchronously with the output order of print data and transforming them corresponding to printing ability. SOLUTION: The data of image signals at (m) level prepared by an image signal generating part 10 of a computer 1 and stored in an image signal storage part 11 are transmitted to the side of a printer 2 while using a signal transmission part 13 and afterwards, signal processing depending on printer characteristics is executed on the printer side. When the characteristic of a printing part 18 at the printer 2 shows (n) level printing, for example, with the (m) level image signal inputted by a reception part 15 as an object, a level converting part 17 executes signal conversion (m>n) from (m) to (n) corresponding to the printer characteristics. Therefore, a compressing processing part 12 of the computer 1 compresses the image signal while fixing compressibility, an extending processing part 16 of the printer 2 extends this (m) level compressed image signal synchronously with the printing-out order, and the level converting part 17 converts this signal corresponding to the printing ability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image signal processing apparatus, and more particularly to a signal processing apparatus in which a computer and a printer are connected.

[0002]

2. Description of the Related Art A device for printing an image signal with a printer is described in Electrophotographic Society of Japan, Vol. 33, No. 2 (1994).
Pages 177 to 184 describe in a paper entitled "Image Quality Control Technology in Bubble Jet Recording." This paper describes various control techniques for printing at high speed and high image quality on the printer side after transmitting a binary image signal created using a computer to the printer.

[0003]

The signal processing for printing includes signal processing on the computer side and signal processing on the printer main body, and the printing ability is determined by the combination of both. However, the above-mentioned related art describes the control in the printer main body, and does not mention the printing characteristics (high speed, high image quality) of the entire system.

For example, even if the image signals are the same, the printing time greatly varies depending on the signal processing capability of the computer, the resolution setting at the time of printing, or the transmission speed of the connection interface between the computer and the printer. There is a problem.

(1) Correspondence to printer characteristics Device characteristics and performance differ depending on the connected printer. For example, since the display device on the computer side and the printer differ in the number of gradations or resolution that can be expressed by one pixel, conversion processing is required. For this reason, the signal processing corresponding to the printer must be executed on the computer side.

(2) Signal processing time A processing time is required to execute signal processing according to the gradation characteristics of the printer. In many cases, signal processing is performed by software so that the configuration does not depend on a specific hardware configuration. For this reason, a great deal of processing time is required for signal processing of color image data having gradation in particular.

(3) Signal Sequence Conversion For example, in an ink jet printer, an apparatus configuration for printing using a plurality of nozzles (ink ejection ports) is widely used. However, when the order of image data transferred from the computer and the order of printing using the nozzles are different, the order of these signals must be converted.

According to the object of the present invention, in a device configuration in which a computer and a printer are connected to perform a print output, it is possible to speed up the print output by the printer without depending on the printer characteristics for signal processing on the computer side. The object is to provide an image processing system.

[0009]

SUMMARY OF THE INVENTION The present invention is an image processing system comprising a computer for outputting an image signal as compressed data and a printing device for printing and recording the output image signal. A means for inputting the compressed data output from the computer, a means for accumulating the input compressed data, a means for decompressing the multilevel compression data stored in the accumulating means, and a decompressed multilevel level It is characterized in that a signal converting means for converting the image signal so as to match the capability of the printing means is provided and the decompressing means expands the compressed data in synchronization with the print data output order of the printing means.

According to the present invention, since the signal processing means is provided on the printing device (printer) side, the conversion processing can be executed according to the characteristics of the printer itself, and the following effects can be obtained.

(1) It is not necessary to prepare a signal converting means depending on the printer characteristic to be externally connected on the computer side.

(2) It is not necessary for the computer to perform conversion based on the signal conversion means, which has the effect of shortening the signal processing time.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

 (1) Basic Configuration One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the basic configuration of the present invention. 1 shows an apparatus configuration in which a computer 1 for generating an image signal and a printer 2 for printing an image signal are connected. Here, the computer refers to a device that generates and displays an image signal, such as a so-called personal computer, workstation, or word processor. Generally, creation, editing, etc. are performed while displaying an image signal on a display device. As the display device 3, a CRT (cathoderay tube), an LCD (liquid cryst
Al display) is widely used to display multi-valued m-level color images.

On the other hand, there are many types of printers such as laser printers and ink jet printers, and the device characteristics and performance are widely distributed depending on the model. One classification method is the number of gradations n per dot to be printed. As a color printer capable of reproducing a large number of gradations per dot, there are a silver salt photographic system, a sublimation dye system and the like, and a multi-valued color image can be printed similarly to the display device described above. However, the printer for multi-level printing is inevitably higher in device cost than the printer for bi-level printing, and many market research results show that the bi-level printing printer is widely used. ing.

Here, when the computer and the printer are connected and used as described above, signal level conversion, color conversion, resolution conversion and the like are indispensable due to the difference in display capability between the two. In the present invention, the m-level image signal created and displayed by the image signal generation unit 10 of the computer 1 and stored in the image signal storage unit 11 is data-transmitted to the printer side using the signal transmission unit 13, and then As described above, the feature of the apparatus configuration is that the signal processing depending on the printer characteristics is basically executed on the printer side. For example, the printing unit 1 of the printer
If the characteristic of No. 8 is n level printing, the level converting section 17 performs signal conversion from m to n (m> n) for matching the m level image signal input by the receiving section 15 to the printer characteristics. Run. Also, the conversion of the resolution of the image signal created on the computer side and the image signal to be printed, color conversion,
The signal processing unit 16 on the printer side performs resolution conversion and the like. FIG. 2A shows an example of the configuration of the conventional method, and FIG. 2B shows the configuration of the present invention. According to the configuration of the present invention, 1) the signal processing depending on the printer does not need to be taken into consideration on the computer side, and 2) the signal conversion is executed by the circuit prepared on the printer side, which enables high-speed signal processing.

The problem here is the data amount of the image signal, which is enormous especially in a color image. Factors that determine the amount of data include screen size, resolution, color signal type,
The number of gradations, etc. Since the transmission time becomes long depending on the transmission capacity of the transmission path 14, the time can be shortened by compressing and converting the data to be transmitted. For the purpose of shortening the data transmission time, it is not necessary to limit the compression method. For example, the widely used JPEG (joint photograp)
hic expert group) method etc. can be used.
However, in particular, by adopting a compression method with a fixed compression rate, the following features can be realized.

1) Flow control of transmission / reception data becomes easy.

2) The signal processing time for compression / expansion can be determined.

3) The memory capacity for storing compressed data can be determined in advance.

4) The relationship between the pixel position of the image signal and the memory address of the compressed data of the signal can be uniquely determined.

Therefore, a great advantage can be realized by providing the compression processing unit 12 and the expansion processing unit 16 having a fixed compression rate on the computer side and the printer side, respectively.

(2) Compression method As a compression method with a fixed compression rate, there are, for example, vector quantization, block approximation encoding, and a JPEG method with a feedback loop for coefficient adjustment added. In addition, the inventors of the present invention previously applied for a patent (Japanese Patent Publication No.
-7688) can be used. As illustrated in FIG. 3, this divides the image into blocks made up of a plurality of blocks and limits the types of colors appearing in these blocks to a number smaller than the number of pixels in the blocks. In this way, the image signal in the block, the signal representing the approximate color,
It is converted into a selection signal indicating selection of the approximate color of each pixel, and as a result, the image signal can be represented with a smaller data amount than the original image. If the conditions in the figure are used, the original image can be converted into compressed data at a fixed compression rate of 1/6.

FIG. 4 shows a signal processing procedure for creating compressed data based on this setting. All of the compression methods described above are signal non-conservation types, which may lead to deterioration of image quality. Therefore, it is desirable that the compression / decompression signal processing procedure be provided with a means for adjusting the characteristic of image quality deterioration so that the characteristic can be set in response to the user's request. From this, one of the features of the present invention is that if the compression rate is increased, the data transmission time becomes faster, but the image quality may be deteriorated. On the other hand, if the compression rate is lowered, the data transmission time will be slightly lengthened. A means to adjust the trade-off relationship that is maintained is prepared.

In order to realize this adjustment function, for example, in the case of the above-mentioned block coding system, 1) block size (4 × 4, 5 × 5, 6 × 6, etc.) 2) approximate number of colors in block ( (2 colors, 4 colors, etc.), etc. are provided.

The compression rate can be set by setting the block size and the approximate number of colors in the initial setting step as parameters.

(3) Image Quality Processing Method To summarize the features of the present invention described above, the following signal processing is prepared as shown in FIG. 5 in order to realize the present invention. FIG. 5 is a diagram illustrating a signal processing procedure in the computer and the printer.

On the computer side, 1) data of the partial area is generated or read from the memory, and 2) compression processing is performed on the image signal created by the user who operates the computer.
3) Send, on the printer side 1) Receive, 2) Expand, 3)
Color conversion, 4) resolution conversion, 5) signal level conversion, 6) signal order conversion, etc. are executed. The above is an example, and it goes without saying that a part of the processing procedure can be changed or addition for realizing another function can be performed. The point is
By using the signal processing means prepared on the printer side, multi-level signal processing can be executed at high speed and with high image quality. Here, the purpose of typical signal processing and the outline of the processing procedure will be described, and the device configuration of the present invention will be clarified in the next section.

The color conversion will be described below. Most of the display devices on the computer side use RGB (red green blue) as color signals. On the other hand, most printers are CMYK
(Cyan, magenta, yellow, black) are used. Therefore, conversion of these color signals is indispensable. These color signals are basically numerical values independent of each pixel forming an image, and conversion processing is also performed for each pixel. The conversion method is not limited, but enormous signal processing is required even if a method such as table search is used.

The resolution conversion will be described below. The display device on the computer side and the printer often differ in the number of pixels arranged per unit length (or area). For example, the former is 72 dpi based on the CRT dot pitch.
There is a case where the resolution of the printer is, for example, 200 dpi, while it is (dot per inch).
Therefore, a resolution conversion means for producing an image signal to be printed out by the printer is required.

The signal level conversion will be described below.
Most of the display devices on the computer side can display multi-valued levels, but the gradation levels that can be printed by the printer differ depending on the model. In general, the more reproducible gradation levels, the more expensive the model is, and most inexpensive and popular printers have a reproduction capacity of only about two gradation levels. For this reason,
A signal processing means for performing pseudo halftone reproduction known as a dither method or an error diffusion method is widely used.

The signal order conversion will be described below. The order in which the image signals for printing are used differs depending on the printer model. For this purpose, it is necessary to change the signal order.

(4) Configuration on Computer Side FIG. 6A shows an example of the signal processing procedure executed on the computer side. What is basically executed is compression processing and transmission processing. The computer itself has a general-purpose configuration, and is an example when no new hardware is added. Conventionally, a long processing time is required because color conversion, resolution conversion, and signal level conversion corresponding to printer characteristics are executed by software. However, with the configuration of the present invention, all of these signal processings are unnecessary. However, although the processing time of the compression processing whose main purpose is to shorten the data transmission time is newly required, when the block approximation coding method described above is used, the processing method is relatively simple, By adding software processing based on FIG. 4 or adding hardware for executing the procedure in FIG. 4, there is no problem in terms of processing time.

Further, a means for setting the degree of the image quality deterioration by the user is prepared in response to the influence of the image quality deterioration due to the compression processing. For this, for example, a print condition setting screen can be presented to the user to provide a so-called interactive setting procedure.

FIG. 6B shows an example of the transmission procedure between the computer and the printer. After issuing a print start request from the computer to the printer to confirm the ready state, the image signals stored in the memory are read out in partial area units, converted into compressed data, and sent out. Then, the procedure is repeated until the transmission of the necessary data is completed. Here, since the transmission data is data obtained by compressing the image signal of the partial area including a plurality of lines at a fixed compression rate, the amount of data to be transmitted can be determined in advance. Therefore, since the time required for transmission is clear, management of the above transmission procedure is ready. In addition, there is a feature that the capacity of the buffer that must be prepared on the receiving side can be determined.

(5) Configuration on the Printer Side FIG. 7 shows an example of the device configuration on the printer side. The basic items of signal processing executed on the printer side are 1) reception, 2) expansion, 3) color conversion, 4) resolution conversion, 5) signal level conversion, and 6) signal order conversion.

Unlike the conventional method of receiving the result of processing on the computer side, the multi-level image signal created by the computer is input as it is (although it is affected by the compression / expansion processing), so various signal processing is performed. Can be executed.
In FIG. 7, the processor 201 is the program memory 2
Based on the program installed in 02, the overall management and various signal processing are executed. First, the data input / output interface 204 is used to coordinate the operation with the connected computer. For example, if there is a request to start printing,
Initialization of the printer itself or confirmation of the capability is performed, and if an image signal for printing can be input, a signal indicating that is returned to the computer. The subsequently input image signal is temporarily stored in the memory 205, waiting for the order of various signal processing, or synchronizing with the operation of the printing mechanism 207. Most of the signal processing for the image signal executed on the printer side refers to a pixel signal of about 10 pixels at most centering on the pixel of interest, and is therefore suitable for hardware implementation, and ASIC (application specific IC)
It can be summarized in 203. Most of the operating conditions of the printer can be posted on the display device of the computer by sending it to the computer as a signal. Further, the same content can be displayed on the panel 206 included in the printer itself.

Regarding the character data, a character code can be received from the computer side and an image signal composed of a set of dots can be created using the character data provided in the printer side. In FIG. 7, for example, the program memory 202
Such signal processing can be executed by accumulating character data in a part of. In this case, a memory for accumulating the dot information of the expanded character is required, but the memory 205 of FIG. 7 can be used. Here, since the compressed data stored in the memory 205 has a fixed compression rate and the pixel position and the memory address can be uniquely determined, the compressed data stored in the memory corresponding to the image area into which the character data is written Data can be rewritten. That is, it is possible to combine the compressed data sent from the computer with the character data expanded on the printer side, and store the obtained combined data in the memory 205. As a result, there is no distinction in the data flow at the time of printing, and printing can be performed by a single signal processing procedure.

Next, a device configuration in which error diffusion processing and signal order conversion are combined will be described. In general, the error diffusion processing is a method of locally storing the density by reflecting an error component generated by the binarization processing of each pixel on an adjacent pixel signal. For example, if the input multilevel signal of the target pixel is x
(I), If the binarized signal is z (i), the error component (x
(i) -z (i)) is added to the signals of adjacent pixels without being ignored. Since the error component is generally transmitted to a plurality of pixels, until the time when the signal processing of the pixels is executed,
The error component must be saved. Therefore, when the signal processing is executed for each line, an error component memory for at least one line for storing the error component is required.

By the way, many ink jet printers simultaneously print a plurality of lines using a plurality of nozzles. As an example, as shown in FIG. 8A, consider a case where N lines are printed at the same time while scanning in the line direction. For this purpose, an error diffusion process for creating print data is executed in advance over N lines,
N line print data is stored in memory. Then, while reading N pixel data corresponding to the nozzle position of the print head from the memory, N lines are simultaneously scanned and printed in the line direction. This means that the order conversion means is necessary because the order of data transfer from the computer, the order of signal processing for error diffusion processing, and the order of data transfer for printing are different. Further, at least N line print data and an error component memory for one line are required as a memory capacity.

Here, the change of the signal processing order of the error diffusion processing will be considered with reference to FIG. With the range covered by one scan of the print head as a unit of one image, the signal processing of the error diffusion processing is executed in the image unit in synchronization with the scan operation of the print head. If the nozzles of the print head are arranged in a line in the direction orthogonal to the scanning direction, the signal processing of each pixel is executed in the nozzle direction. This divides the screen into N line units,
This is equivalent to rotating the signal processing order of the conventional method by 90 degrees for each divided area. The advantage of this method is that it is not necessary to store N-line print data in memory in advance because the signal can be generated in synchronization with the scan of the print head. Further, if the error component is transmitted in the scan direction of the print head, the error diffusion process can be executed by accumulating the error component for N pixels. Also, the number of nozzles on the print head is not 2
When the nozzles are arranged in a dimension, the pixel components within the arrangement range of the nozzle may be stored. Even in this case, if the error diffusion processing is executed in the scan direction of the print head, that is, in the line direction, it is sufficient to accumulate the error components for N pixels. Then, the image data is stored in the compressed data format, and the expansion, the error diffusion processing, and the other signal processing are executed at high speed in accordance with the print output order, whereby the memory capacity can be significantly reduced.

By the way, when the print head is scanned and printed every N lines as shown in FIG. 9A, image quality deterioration due to discontinuity may occur at an image boundary formed by the print head scan. The factors include the accuracy of the feed mechanism of the print head and the discontinuity of the transmission order of error components. For the latter, see Figure 1.
As shown in FIG. 0 (1), this does not pose a problem when the entire one screen is processed in sequence, but as shown in (2) in the figure, the error diffusion transmission is closed within the N line image unit, and the image unit is closed. This occurs when communication is not performed between them.

In order to prevent this, the following two device configurations can be used. The first configuration prepares an error component memory for one line as shown in FIG. 10 (3) while executing the error diffusion processing in units of N lines, so that the error components of the error components are crossed across the boundaries of the image units. Transmission is performed and the error component transmission direction is two-dimensionally parallel and orthogonal to the scan direction, thereby improving the density continuity of the boundary portion. The error component memory stores the error component transmitted to the leading line of the next N line image unit. Then, in the error diffusion process for the next N lines of image units, the signal read from the error component memory can be used as the error component transmitted from the line immediately above. By transmitting the error component between the lines in this way, the same result as that obtained by converting the entire image by one-time error diffusion processing can be obtained. This method has the advantage that the signal processing of the error diffusion processing can be executed in synchronization with the scan of the print head, and the continuity of error component transmission can be maintained. This is effective when there is an error component memory for one line and the accuracy of the feed mechanism of the print head is high.

As a second configuration, by performing sub-sampling printing as shown in FIG. 9B, the discontinuity at the boundary can be made invisible. The N line expansion, error diffusion processing and other signal processing are performed in synchronization with the scan of the print head, and the results are subsampled and printed. As a result, the border between image units of N lines in the printed image becomes visually unclear,
The concentration continuity at the boundary can be improved. When such printing is performed, one line data is printed by scanning a plurality of times. If the print data is stored in the memory, the data may be read from the memory a plurality of times and output to the print head. However, this requires at least a memory for storing the N line print data. A second device configuration example for solving this is shown in FIG. 11 (1).
And (2). The image data sent from the computer is stored in compressed data format, the necessary data is expanded in synchronization with the print scan, signal processing such as error diffusion processing is performed, and then the data to be printed is subsampled. By outputting the data to the print head afterwards, it is possible to reduce the memory capacity and prevent image quality deterioration. Since subsampling printing is performed, decompression and error diffusion processing are executed a plurality of times for the same pixel, but since signal processing for this purpose can be executed at high speed, there is no problem in the device configuration. Here, the subsampling ratio and pattern can be set to be constant or variable.
It can be set according to the number and arrangement of the nozzles of the print head. Further, the sub-sampling ratio and pattern can be adaptively set according to the characteristics of the image to be printed.
For example, it is possible to set so that subsampling is not performed for a character / graphic image or the like and subsampling is performed for a natural image or the like. The distinction between the two can be performed by the operator instructing the print start to specify the image type or by using a means for determining the signal property (for example, the distribution of the signal amplitude). Further, the sub-sampling ratio and the pattern can be set in accordance with the operator's requirements regarding the printing speed and the image quality. In this way, it is possible to improve the printing speed of the character / graphic image and the image quality of the natural image.

The setting of N lines for creating divided images can be set as the number of lines of the image matching the nozzle arrangement area of the print head. Further, in order to reduce the influence of the area boundary condition in the error diffusion processing of the N-line divided image described above, the N lines are set so as to provide a plurality of additional areas around the nozzle arrangement area of the print head, and As the print data, data corresponding to the print head nozzle position in the area can be cut out and used. The compressed data is stored in the memory in order to perform such signal processing. However, when the compression / expansion processing is performed in units of a plurality of pixels, for example, the unit pixel number of the compression / expansion processing and the value of the N line. Can also be set in relation to multiples.

As described above, according to the present invention, most of the signal processing is executed by the hardware provided on the printer side, so that a high-speed and high-quality printed image can be output. Also, since the correspondence between pixel positions and memory addresses can be set uniquely by setting the compressed data stored in the memory to a fixed compression ratio, it is possible to read the memory to output image data in synchronization with the print head and send it from the computer. The merit of accumulating the incoming data in the memory with a simple processing procedure is obtained. On the other hand, in the run-length coding, the JPEG coding, etc., the compression rate varies depending on the design, so that the procedure of memory storage and memory reading becomes complicated.

(6) Bidirectional scan printing In order to shorten the printing time, printing may be performed in synchronization with the left and right bidirectional scanning operation of the print head. Again, in this case,
Signal processing such as decompression of compressed data and error diffusion processing can be executed based on the timing and data amount required for printing. In addition, for color printing, the scanning operation of the print head and the type of color to be printed may be set based on a certain rule, and the printing operation may be executed. For example, the color type to be printed can be determined in advance depending on the right and left scanning directions. By storing the compressed data with a fixed compression ratio in the memory, the data for printing can be uniquely read from the memory regardless of the print data creation order such as the scanning direction and the color type.

(7) Signal conversion By setting a color signal that does not depend on the characteristics of the device that handles the color signal, the color signal to be transmitted can be standardized.
For example, in ITU-T T.42 which is an international standard, CIE Lab is set as a standard color signal used in a communication terminal. Needless to say, such a standard signal can be used as a transmission signal, but color conversion on the printer side is necessary.

Further, when the image signal to be displayed on the display of the computer is printed, the number of pixels is converted. For example, an image signal for display composed of 640 × 480 pixels is displayed in A4 size (210 × 290 mm), 2
Printing at 00 dpi requires enlargement processing to increase the number of pixels.

Here, it is noted that the compressed data format based on the above-described compression method is composed of color signals that approximate the inside of a block and selection signals that indicate the arrangement of the approximate color signals. As shown in FIG. 12A, R is used for conversion of color signals.
Considering an example of converting a GB signal into a CMY signal, it can be seen that color conversion only needs to be performed on an approximate color signal of the compressed data. At this time, it is not necessary to perform signal processing on the selection signal. Further, as shown in FIG. 12 (2), by enlarging the selection signal, the number of pixels can be increased, that is, the image can be enlarged. This is reduction, rotation,
Signal processing such as can be similarly realized.

11 (1) and 11 (2) are configuration examples distinguished by the processing procedure of color conversion, and FIG. 11 (1) shows that each pixel forming an image is subjected to color signal conversion. On the other hand, in FIG. 2B, the color signals that approximate the inside of the block may be targeted. As compared with FIG. 11A, the configuration of (2) can realize high-speed signal processing because the amount of data to be processed is small.

(8) Printer Characteristics With the above-mentioned configuration, it is possible to eliminate the need to previously register the details of the characteristics of the printer connected to the computer in the computer. If the signal transmitted from the computer to the printer is a multi-valued color signal set according to some standard, density characteristics, color correction, and
The signal processing for adjusting the resolution may be executed on the printer side. Even if the color signal does not conform to the standard, it is possible to adjust the color by using the color correction unit provided on the printer side. Alternatively, by printing a color image corresponding to the test pattern and measuring the printing result,
It is possible to calculate a parameter for color correction and set the parameter in the color correction means provided on the computer side or the printer side.

On the computer side, a processing procedure called driver software for setting basic printing conditions and executing data transmission is required. According to the present invention, color signal processing depending on the printer type is unnecessary, and a high execution speed can be realized.

In the following, a numerical example for showing the effect of the above-described embodiment of the present invention will be obtained in a configuration in which a personal computer (personal computer) as a computer and an ink jet printer as a printer are combined as shown in FIG.

Image data created and displayed on the computer side is
If the size is A4 (210 × 290 mm), 72 dpi, and 8 bits for each of RGB, the data amount is about 1468 kBytes. On the other hand, the equipment capability of the printer that prints image data is A4 size (210 x 290 mm), 200 dpi, C
One bit for each of MYK. The data amount of the image signal to be printed is about 1888 kByte. Conventionally, the image signal is converted on the computer side and then transmitted to the printer.
From the above results, it can be seen that the image signal subjected to the resolution conversion and the color conversion is larger than the data amount of the original image of the multi-valued level although it is the binary level. Here, the compression processing can be performed on the binary level image data, but, for example, the image data in which the gradation level is expressed by the error diffusion processing is less effective in the compression processing.
It is known that the compression process increases the data amount in some cases.

According to the present invention, 1) since the image data created and displayed on the computer side is transmitted, it is not necessary to perform signal conversion depending on the device capability of the printer.

2) Since the data amount of the original image is compressed and transmitted, the transmission time can be shortened and high-speed print output can be performed. For example, if the compression rate is 1/6, the above data amount can be obtained. For example, the transmission time is about 1/7 compared with the conventional one.
7 (= (1468/6) / 1888). Since the compression rate is fixed, the transmission time does not change depending on the design.

3) High quality printing can be performed by executing signal processing using multi-valued image signals on the printer side. Further, these signal processes can be executed by simple hardware on the printer side, and the processing time conventionally executed on the computer side can be shortened.

[0059]

As described above, according to the present invention, it is possible to prevent the signal processing on the computer side from depending on the printer characteristics in a device configuration for connecting a computer and a printer to print out. Further, the speed of printing output by the printer can be increased, and further, high-quality printing output can be obtained.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of the present invention.

FIG. 2 is a diagram for explaining signal processing sharing between a computer and a printer.

FIG. 3 is a diagram illustrating an example of a compression method.

FIG. 4 is a diagram illustrating a signal processing procedure for creating compressed data.

FIG. 5 is a diagram illustrating a signal processing procedure in a computer and a printer.

FIG. 6 is signal processing on the computer side.

FIG. 7 is a configuration diagram of a printer device.

FIG. 8 is a diagram illustrating error diffusion processing.

FIG. 9 is an explanatory diagram of a printer print order.

FIG. 10 is a configuration diagram of an error component memory.

FIG. 11 is a configuration diagram of a printer signal processing unit.

FIG. 12 is a configuration diagram of a signal conversion unit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Computer, 2 ... Printer, 3 ... Display device, 10 ... Image signal generation part, 11 ... Image signal storage part, 12 ... Compression processing part, 13 ... Signal generation part, 14 ... Reception part, 15 ... Decompression processing part, 16 ... Signal conversion unit, 17 ... Printing unit, 201 ... Processor, 202 ... Program memory, 203 ... ASIC,
204 ... Data input / output interface, 205 ... Memory, 206 ... Panel, 207 ... Printing mechanism.

Claims (6)

[Claims] 1. An image processing system comprising a computer that outputs an image signal as compressed data, and a printing device that prints and records the output image signal, wherein the printing device outputs the compressed data output from the computer. Input means, means for accumulating the input compressed data, means for decompressing the multivalued compressed data stored in the accumulating means, and the expanded multivalued image signal matching the capability of the printing means. An image processing system comprising: a signal converting unit that converts the compressed data so that the compressed data is expanded in synchronization with a print data output order of the printing unit. 2. The image according to claim 1, wherein the computer compresses a multi-valued image signal at a fixed compression rate, and the decompression means decompresses the compressed data at a fixed compression rate. Processing system. 3. The signal conversion means according to claim 1,
An error diffusion processing unit for multi-level image signals is provided, and the error diffusion processing for the entire image is executed by repeating the error diffusion processing for a partial region of the image consisting of N lines a plurality of times. Characteristic image processing system. 4. The image processing system according to claim 3, wherein the error diffusion processing for the partial area consisting of N lines is sequentially performed in a direction orthogonal to the line direction. 5. The printing apparatus according to claim 1, further comprising means for sub-sampling image data for printing, wherein the positions of the sub-sampling are sequentially switched to complement sampling pixels by printing a plurality of times. Characteristic image processing system. 6. The image processing system according to claim 3, wherein the number of N lines for creating the partial area is set to a value exceeding the number of image lines corresponding to the nozzle area of the print head.