JP2002236565A - Data converting device, computer, and printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a data converting device for converting data of an RGB gradation image into half-tone image data of CMY requires large storage capacity and then becomes large-sized and expensive if the device incorporates various conversion tables corresponding to print conditions. SOLUTION: Conversion tables corresponding to various print conditions are stored in a computer. When image data are converted, a conversion table corresponding to print conditions is selected and stored in a RAM of the data converting device. Then the image data to be printed are supplied to the data converting device and converted while referring to the conversion table stored in the RAM. Consequently, the conversion table corresponding to the print conditions is read in the RAM, and thus the image data can be converted while referring to the proper conversion table without storing many conversion tables into the data converting device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for converting image data input from a computer or the like into a data format printable by a printer while referring to a predetermined conversion table and outputting the converted data.

[0002]

2. Description of the Related Art In a printing apparatus capable of printing a color image, generally, by appropriately mixing (subtractive color mixing) the three colors of cyan (C), magenta (M), and yellow (Y), all the colors are subtracted. It expresses colors and prints color images.
On the other hand, in a computer or a digital camera which is a device for supplying a color original to a printing apparatus, all colors are mixed (additive color mixture) of red (R), green (G), and blue (B). Is expressed. Therefore, in order to print a color image, it is necessary to convert the method of expressing colors by R, G, and B into the method of expressing by C, M, and Y.
For this color conversion, a general-purpose computer or a dedicated data conversion device is used. Also, since the resolution of the color document supplied to the printing device does not always match the resolution of the printing device, the resolution of the color document is converted by these general-purpose computers and data converters to match the resolution of the printing device. In some cases.

[0003] A method of expressing colors by mixing R, G, and B is as follows.
Regarding the technique of converting into a representation method using a mixture of C, M, and Y, various methods based on Neugebauer theory are known. However, if the calculation based on the theory is performed every time color conversion is performed, No quick conversion is possible. Therefore, when color conversion is actually performed by a computer or a data conversion device, various values are theoretically calculated in advance, the results are summarized in a conversion table, and the color conversion is performed by referring to the conversion table. Going quickly.

By the way, even when color conversion is performed with reference to the same conversion table, subtle differences in colors appearing on the printing paper may occur due to differences in the background color of the printing paper and compatibility with the ink used. is there. For example, if printing is performed on a yellowish printing paper, the obtained image naturally becomes slightly yellowish. In addition, there may be a case where the appearance color differs depending on the amount of ink bleeding. Therefore, in order to accurately represent the color of the original and perform high-quality printing, prepare various conversion tables according to the type of printing paper, and perform color conversion using an appropriate conversion table. Must be.

However, since a large storage capacity is required to store the conversion table, if all possible conversion tables are stored in the data conversion apparatus, the apparatus becomes large and the price increases. Problem arises. However, if only a small number of types of conversion data cannot be stored in the data conversion device, it is not always possible to perform color conversion using a suitable conversion table. Cases can arise.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art, and has as its object to appropriately convert image data.

[0007]

Means for Solving the Problems and Their Functions and Effects In order to solve at least a part of the above problems, the first data conversion device of the present invention has the following configuration. A first data conversion device of the present invention is a data conversion device that converts image data input from a computer into a data format printable by a printing device while referring to a predetermined conversion table, and outputs the data. Storage means for rewritably storing the conversion table supplied from the computer in accordance with image printing conditions; receiving means for receiving the image data; and referring to the conversion table stored in the storage means. A conversion unit for converting the image data received by the reception unit, and an output unit for outputting a result of the data conversion,
The gist is that it is configured separately from the computer.

[0008] In the first data conversion device,
The image data input from the computer is converted into a data format that can be printed by a printing device with reference to a predetermined conversion table and output. At this time, the conversion table supplied from the computer according to the printing conditions of the image is stored in a rewritable manner, and the data format is converted with reference to the stored conversion table. Therefore, even if a large number of conversion tables are not stored, a conversion table corresponding to the printing condition of the image can be used, and the necessary conversion is appropriately performed in a data conversion device separate from the computer. be able to.

In the first data conversion apparatus, the conversion table may be received from the computer in a compressed state, and the conversion table may be decompressed by the data conversion apparatus and then stored in the storage means. It is preferable that the conversion table is compressed because the time required to receive the conversion table from the computer can be shortened by an amount corresponding to the reduced data amount.

In the first data conversion device,
The conversion table received from the computer may be interpolated and stored in the storage unit after a predetermined accuracy. Interpolation after receiving the conversion table is preferable because the time required for reception can be reduced as compared with the case where the conversion table is received after interpolation. Furthermore, if the received conversion table is interpolated to a predetermined accuracy by the data conversion device, there is an advantage that it is not necessary to make the conversion tables stored in the computer uniform in accuracy.

Here, the conversion table in this specification and the accuracy of the conversion table will be described below. First, a conversion table is a set of combinations of numerical values that associate argument values with variable values when there is a relationship that when the argument value is determined, one variable value is determined. And Although the number of arguments may be one, in general, one variable value is often determined by a plurality of arguments. In this case, a set of the values of the plurality of arguments corresponds to the variable value. are doing. For example, when the values of two arguments X and Y are determined, and there is a relationship in which one variable Z is determined, the pair (X, Y) of two arguments and the variable Z correspond. Therefore, the conversion table in such a case is a collection of a plurality of combinations of a set of arguments and a value of a variable. Further, one conversion table generally includes a plurality of combinations of numerical values, but in the present specification, it is assumed that one conversion table includes only one combination.

Next, the accuracy of the conversion table indicates a numerical value indicating how fine a combination of numerical values constituting the conversion table exists for a certain argument. There are various ways of expressing fineness in which a combination of numerical values exists. For example, when a combination of numerical values is present at equal intervals with respect to the argument of interest, it is conceivable that the combination of numerical values is expressed by an interval of the numerical value. May be represented by the total number of combinations. In this specification,
The fineness of the combination of numerical values may be expressed by any method.

In the first data conversion device, the image printing conditions are received together with the image data, and the received printing conditions match the printing conditions corresponding to the conversion table stored in the data conversion device. The conversion table corresponding to the printing condition may be received from the computer only when there is no printing condition. If the received printing conditions match the printing conditions for the stored conversion table, the conversion table received from the computer is considered to be the same as the stored conversion table. You do not need to receive. Therefore, it is preferable to receive the conversion table from the computer only when the printing conditions do not match, because the conversion table stored in the data conversion apparatus is not received repeatedly.

Further, in the first data converter,
The following is also preferable. First, a plurality of conversion tables selected by the computer based on at least the printing resolution of the printing apparatus and the type of printing paper are received from the computer and stored. Next, in addition to the image data, an image attribute indicating whether or not the image is a natural image is received from the computer. Here, in the present specification, the image attribute refers to a property of an image determined by whether or not the content of the image is a natural image. When the first data converter converts image data, the data may be converted while switching the conversion table to be referred to on a pixel-by-pixel basis based on the image attribute. In this way, even if the image to be printed is a combination of individual images having different image attributes, data conversion can be performed by referring to a conversion table suitable for each image. It is.

The computer of the present invention employs the following configuration in order to solve at least a part of the above-mentioned problems. The computer according to the present invention is a computer that supplies the image data to a data conversion device that converts the image data into a format printable by a printing device and outputs the image data by referring to a predetermined conversion table. Image data output means for outputting the image data to the data conversion apparatus, conversion table storage means for storing various conversion tables corresponding to image printing conditions, and conversion table storage means A conversion table selecting means for selecting one of the conversion tables according to an image printing condition, and a conversion for outputting the selected conversion table to the data conversion apparatus prior to the conversion of the image data. The summary is that the data conversion device is provided separately from the data conversion device.

Such a computer supplies the image data to a data conversion device provided separately, and the data conversion device refers to a predetermined conversion table and converts the image data into a data format printable by a printing device. Convert. At this time, the computer selects one conversion table corresponding to the printing conditions of the image from various conversion tables stored corresponding to the printing conditions of the image, and converts the selected conversion table into a data conversion device. To supply. The data converter converts image data with reference to a conversion table supplied from a computer. In this case, since the conversion table is supplied from the computer in accordance with the printing conditions of the image, the data conversion device can appropriately perform the necessary conversion without storing a large number of conversion tables.

In such a computer, various conversion tables corresponding to image printing conditions are compressed and stored.
When outputting the conversion table, the selected conversion table may be decompressed before being output. This is preferable because the storage capacity of the computer required for storing various conversion tables can be reduced. Further, since the compressed conversion table is decompressed by the computer, it is not necessary to provide the data conversion device with a decompression function, and accordingly, there is an advantage that the data conversion device can be avoided from being enlarged or expensive. .

Further, in such a computer, various stored conversion tables may be interpolated to a predetermined accuracy and then output to the data conversion device. The conversion table before interpolation can be stored with a smaller storage capacity than the conversion table after interpolation, so if various conversion tables are stored in a state before interpolation, the storage capacity required for storing the conversion table Can be preferably reduced. Furthermore, since the conversion table output to the data conversion device is output after being interpolated to a predetermined precision, various conversion tables stored in the computer are:
There is also an advantage that it is not necessary to store data with the same accuracy. Further, since the conversion table is interpolated in the computer, it is not necessary to provide an interpolation function in the data conversion device, and accordingly, there is an advantage that the data conversion device can be prevented from being enlarged or expensive.

Further, in such a computer, when selecting the conversion table in accordance with the printing conditions of the image, at least the printing resolution of the printing apparatus and the type of printing paper are used.
A conversion table may be selected. Depending on the printing resolution of the printing device and the printing paper, the conversion table to be referred to may need to be changed.If a conversion table is selected based on these conditions, conversion can be performed according to the image printing conditions. It is preferable that a table can be selected. The reason why the conversion table must be changed depending on the printing resolution of the printing apparatus and the printing paper will be described later.

In such a computer, the following is also preferable. First, print conditions corresponding to the conversion table previously supplied to the data conversion device are stored. Next, when the image data is converted, it is determined whether or not the stored printing conditions are different from the printing conditions of the image. If the two conditions are different, the conversion table is selected and supplied to the data conversion device, and the printing condition corresponding to the stored conversion table is updated. In this way, only when it is necessary to rewrite the conversion table stored in the data conversion device,
This is preferable because a conversion table is output, and time for outputting the conversion table can be saved.

Further, such a computer may be configured as follows. A conversion table is stored for each condition including at least the printing resolution of the printing apparatus, the type of printing paper, and the image attribute. When converting the image data, first, a plurality of conversion tables having different image attributes are selected based on at least the printing conditions relating to the printing resolution and the type of printing paper, and the selected conversion tables are output to the data conversion device.
Next, while determining the image attribute of the image to be printed, the determined image attribute is supplied to the data conversion device in addition to the image data. Further, by giving an instruction from the computer based on the image attribute, the conversion table to be referred to at the time of data conversion is switched in pixel units. In this way, even if an image to be printed is a combination of individual images having different image attributes, data can be converted while referring to a conversion table suitable for each image. .

Further, the second data conversion device of the present invention comprises:
In order to solve at least a part of the problems described above, the following configuration is adopted. A second data conversion device according to the present invention converts image data input from an imaging device such as a digital camera or a color scanner into a data format printable by a printing device while referring to a predetermined conversion table, and outputs the data. A conversion table storing means for storing various conversion tables according to printing conditions of an image, and converting the image data from among the conversion tables stored in the conversion table storage means. Conversion table selecting means for selecting one according to printing conditions; receiving means for receiving the image data; and converting the image data received by the receiving means with reference to the conversion table selected by the conversion table selecting means. And a conversion unit that outputs the result of the data conversion, and is configured separately from the image device.

In the second data conversion device,
Image data input from an image device such as a digital camera or a color scanner is converted into a data format printable by a printing device with reference to a predetermined conversion table. At this time,
The data conversion apparatus selects one of various stored conversion tables according to the printing condition of the image, and refers to the selected conversion table to determine the data format of the image data supplied from the image device. To convert. This is preferable because the image data can be directly output from the image device to the data conversion device and converted into a data format printable by the printing device without using a computer.

Further, in the second data conversion device, the conversion table may be received from an image device. This is preferable because, when image data is received from the image device and the data format is converted, a necessary conversion table can also be received from the image device.

In the second data conversion device,
The conversion table may be received by communicating with a computer provided separately from the data conversion apparatus, and the conversion table stored in the data conversion apparatus may be rewritten with the received conversion table. In this way, since the necessary conversion table can be received from the computer, the image data can be appropriately converted without storing all the conversion tables in the data conversion device.

Further, in the second data conversion device, a standard conversion table is stored in the data conversion device, and if the conversion table corresponding to the printing condition of the image is not in the conversion table storage means, The image data may be converted with reference to a standard conversion table. If an appropriate conversion table is stored as a standard conversion table, even if the corresponding conversion table does not exist in the conversion table storage means, it is possible to obtain a print image of generally good image quality. Is preferable.

The printing apparatus of the present invention employs the following configuration in order to solve at least a part of the above-mentioned problems. 13. A printing apparatus according to claim 1, further comprising: a data conversion apparatus according to claim 1; and a printing apparatus configured to receive image data whose data format has been converted by the data conversion apparatus and print an image corresponding to the input image data. And the data conversion device is configured integrally with the printing device.

In this printing apparatus, image data whose data format has been converted is received from the data conversion apparatus according to claim 1 or 12 which is integrated with the printing apparatus, and an image corresponding to the image data is received. Print. This is preferable because the printing device and the data conversion device can be compactly configured.

In order to solve at least a part of the above problems, the data conversion method of the present invention employs the following configuration. The data conversion method of the present invention, the image data output from the computer, while referring to a predetermined conversion table,
A data conversion method for converting a data into a data format printable by a printing apparatus and outputting the converted data. The conversion method selects a conversion table corresponding to an image printing condition from various conversion tables stored in the computer in advance. The selected conversion table is stored in a data conversion device provided separately from the computer in a rewritable manner, and image data supplied from the computer is stored while referring to the stored conversion table. The point is to convert.

In this data conversion method, the image data output from the computer is converted into a data format printable by a printing device with reference to a predetermined conversion table and output. Here, the conversion table referred to at the time of data conversion is supplied from a computer and stored in the data conversion device in a rewritable manner. Therefore, if a conversion table suitable for printing conditions is supplied from a computer and data conversion is performed with reference to this conversion table, even if a large number of conversion tables are not stored in the storage means in the data conversion device, Necessary data conversion can be appropriately performed.

[0031]

Other Embodiments of the Invention The present invention includes the following other embodiments. That is, a data conversion device that converts image data input from a computer into a data format printable by a printing device while referring to a predetermined conversion table, and outputs the converted data. The conversion table supplied from the storage means for rewritably storing, the receiving means for receiving the image data, and the image data received by the receiving means while referring to the conversion table stored in the storage means. Conversion means for converting the data, and output means for outputting the result of the data conversion,
This is an aspect as a data conversion device used by being attached to the computer.

[0032]

DETAILED DESCRIPTION OF THE INVENTION Configuration of Apparatus An embodiment of the present invention will be described based on examples. Figure 1
FIG. 1 is an explanatory diagram illustrating a configuration of a printing apparatus including a data conversion device 10 according to an embodiment of the present invention. As shown in the figure, the printing apparatus has a configuration in which a computer 80, a data conversion apparatus 10, and a printer 20 are connected. When a predetermined program is loaded and executed on the computer 80, the printing apparatus as a whole is Function as The computer 80 outputs the color image data ORG to the data conversion device 10, and the data conversion device 10
The received color image data ORG is converted into a data format printable by the printer 20, and then output to the printer 20. The printer 20 prints a color image by forming dots on printing paper based on the converted image data FNL received from the data conversion device 10. As a result, a color image corresponding to the color image data output from the computer is obtained on the printing paper.

The computer 80 comprises a CPU 81 for executing various arithmetic processing, a ROM 82, a RAM 83, a hard disk 84, an interface 85, and the like. These are connected by a bus (not shown).
Data can be exchanged with each other. ROM8
Reference numeral 2 is used to store in advance programs and data necessary for the CPU 81 to execute various arithmetic processes. The RAM 83 is used to temporarily store programs and data necessary for the CPU 81 to perform various arithmetic processing. The hard disk 84 includes a ROM 82 and an R
It is used to store programs and data that cannot be stored in the AM 83. The interface 85 is used for the computer to exchange data with the outside.

The color scanner 24 connected to the outside of the computer 80 reads a color original and converts it into image data that can be interpreted by the computer. Further, if the computer 80 is connected to the public telephone line PNT via the modem 91, it becomes possible to receive necessary data from the server SV on the external network.

When the power of the computer 80 is turned on, the RO
The operating system stored in the M82 and the hard disk 84 is activated, and various application programs operate under the management of the operating system. A color document to be printed is created using an application program, and is output to the data conversion device 10 via the interface 85.
In some cases, a color document is created by processing a color image fetched from outside via the color scanner 24 or the modem 91 by an application program.

As shown in the figure, the data conversion device 10
A CPU 11 for performing various arithmetic processes, a ROM 12 for storing programs and data necessary for various arithmetic processes in advance,
RAMa13 for storing data received from the computer 80, RAM for temporarily storing various calculation results
b14, interface 1 for receiving data from outside
5, an interface 16 for sending data to the outside. These are connected by a bus 17 so that data can be exchanged with each other. When the power is turned on to the data converter 10, the ROM 1
2 is started, and preparation for receiving data from the computer 80 is completed.

When the data conversion is started, the computer 8
0 first outputs various necessary data to the data converter 10, and then outputs image data ORG.
The data conversion device 10 stores various data necessary for data conversion in the RAM 13 and converts the subsequently input color image data ORG into a data format printable by the printer 20. This data conversion is performed by the C of the data converter.
The data converted by the PU 11 according to a predetermined program is temporarily stored in the RAM b 14 and output via the interface 16 as color image data FNL in a data format printable by the printer 20.

The printer 20 is a color printer capable of printing a color image. In this embodiment, a color image is printed by forming dots of four colors of cyan, magenta, yellow and black on a printing paper. You are using an inkjet printer. Of course, it is also possible to use another type of color printer such as a laser printer or a thermal transfer printer.

FIG. 2 shows a schematic configuration of the color printer 20 of this embodiment. As shown, the color printer 20 drives a print head 41 mounted on a carriage 40 to eject ink and form dots.
A mechanism for reciprocating the carriage 40 in the axial direction of the platen 36 by the carriage motor 30, a mechanism for transporting the printing paper P by the paper feed motor 35, and a control circuit 50. The mechanism for reciprocating the carriage 40 in the axial direction of the platen 36 includes an endless drive between a carriage shaft 30 that slidably holds the carriage 40 erected in parallel with the shaft of the platen 36 and the carriage motor 30. A pulley 32 for stretching a belt 31 and a carriage 4
It comprises a position detection sensor 34 for detecting the zero origin position. The mechanism for transporting the printing paper P is a platen 3
6, a paper feed motor 35 for rotating a platen 36,
It comprises a paper feed auxiliary roller (not shown) and a gear train (not shown) for transmitting the rotation of the paper feed motor 35 to the platen 36 and the paper feed auxiliary roller. Control circuit 50
Controls the movements of the paper feed motor 35, the carriage motor 30, and the print head 41 while exchanging signals with the operation panel 51 of the printer. The printing paper P supplied to the color printer 20 is set so as to be sandwiched between the platen 36 and the paper feed auxiliary roller, and is fed by a predetermined amount according to the rotation angle of the platen 36. Also,
The ink cartridges 42 and 43 are mounted on the carriage 40. The ink in the cartridge is ejected from the print head 41 by the method described below, and forms dots on printing paper.

FIG. 3A is an explanatory diagram showing the internal structure of each color head. The ink discharge heads 44 to 47 of each color are provided with 48 nozzles Nz for each color, and each nozzle is provided with an ink passage 48 and a piezo element PE on the ink passage. As is well known, the piezo element PE is an element that distorts the crystal structure due to the application of a voltage and converts electro-mechanical energy very quickly. In the present embodiment, by applying a voltage having a predetermined time width between the electrodes provided at both ends of the piezo element PE, the piezo element PE expands by the voltage application time as shown in FIG. One side wall of the ink passage 48 is deformed. As a result,
The volume of the ink passage 48 contracts in accordance with the expansion of the piezo element PE, and the ink corresponding to the contraction is discharged as particles Ip from the nozzle Nz at a high speed. This ink Ip
Penetrates into the printing paper P mounted on the platen 36, thereby forming dots on the printing paper P.

In the color printer 20 having the above-described hardware configuration, the ink discharge heads 44 to 4 of each color are driven by driving the carriage motor 30.
7 is moved in the main scanning direction with respect to the printing paper P, and the paper feed motor 35 is driven to move the printing paper P in the sub-scanning direction. Under the control of the control circuit 50, while repeating the main scanning and the sub-scanning of the carriage 40,
By driving the print head 41 at an appropriate timing, the color printer 20 prints a color image on printing paper.

Although the present embodiment uses the color printer 20 of the type that discharges ink using the piezo element PE as described above, a printer that discharges ink by another method may be used. . For example, the present invention may be applied to a printer of a system in which a heater arranged in an ink passage is energized and ink is ejected by bubbles generated in the ink passage.

B. Data Conversion Process As described above, the color printer 20 has a function of printing a color image, but the data format of image data that can be handled by the color printer 20 is handled by another image device such as the computer 80 or a digital camera. The format of the image data is different. Therefore, in order to print a color image from the computer 80 or the like with the color printer 20, it is necessary to convert the data format. FIG. 4 shows an outline of a flowchart of the data conversion process.

In the computer 80, the image is handled as matrix data, that is, as a large table in which a number of numbers are arranged vertically and horizontally (for example, every 1000 rows). Each cell constituting the table is called a pixel, and the computer 80 interprets the pixel value (gradation value) as the brightness at that point. Since a black and white image can be considered as having bright and dark places distributed two-dimensionally, a monochrome image can be expressed by appropriately distributing the gradation values. In the computer 80, the gradation value can usually take a value between 0 and 255, and the gradation value 0 represents the darkest state and the gradation value 255 represents the brightest state. In the computer 80, the color image is a bright / dark image of each color of red, green, and blue, that is, an R image, a G image,
The B image is treated as being synthesized.

When such image data is printed by the printer 20, resolution conversion is first performed (step S1).
10). This is the following processing. For example, consider a case where image data composed of 1000 × 1000 pixels vertically and horizontally is printed in a size of 10 cm vertically and horizontally. In this case, one pixel corresponds to 1 mm on the printing paper. The size of one pixel on the printing paper corresponds to the size of the image to be printed. here,
Since the number of dots formed by the printer per unit length is determined by the model, the number of dots formed per pixel differs depending on the size of an image to be printed. As described above, if the number of dots formed per pixel is different, it is inconvenient for data processing.Therefore, the number of pixels is reduced by thinning out pixels, or conversely, the number of pixels is increased by interpolation. It is convenient to adjust in advance so that the number of dots formed per hit becomes a predetermined value. Such a process is a process called resolution conversion.

When the resolution conversion processing is completed, the color conversion processing is started (step S112). As described above, a computer generally represents a color image in three colors of red (R), green (G), and blue (B), but a printer generally represents a color image in cyan (C), magenta, Expressed in three colors, yellow. Therefore, it is necessary to change the method of expressing colors of three colors of R, G, and B to the method of expressing colors of three colors of C, M, and Y. In the color conversion processing, such conversion is performed. When the color conversion process is performed, R, G, and B image data each having 256 gradations are converted into C, M, and Y image data having 256 gradations. Details of the color conversion processing will be described later.

In the color conversion process, a process called under color removal is also performed. The undercolor removal is a process of extracting a black (K) component from the C, M, Y image data to generate C, M, Y, K color image data. FIG. 5 is a conceptual explanatory diagram of the undercolor process. FIG. 5A shows the gradation values of the pixels from which the undercolor is to be removed, and shows the case where the gradation values of C, M, and Y are Vc, Vm, and Vy. Theoretically, if three colors of C, M, Y are mixed in equal amounts, K
(Black) is obtained, the state of FIG.
In the state of (b), that is, K of the gradation value Vy, C of the gradation value (Vc-Vy), and M of the gradation value (Vm-Vy)
Can be replaced with a mixed state. When such replacement is performed, equal amounts of C, M, and Y3
Since the color ink can be replaced with the K1 color, the amount of ink used is reduced, which is preferable from the viewpoint of ink duty. Also, there is an effect that the printed image becomes a tight image as a whole. Actually, in consideration of the decrease in the brightness of the entire image, the image is not replaced as theoretically. Instead, a K of the gradation value Vk smaller than Vy is used to make an equivalent C · M ·
The three colors Y are replaced (FIG. 5C). Such processing is undercolor processing.

When the color conversion is completed, as shown in FIG.
A process called halftoning is started (step S114). The image data after color conversion is C, M, Y, K
, And the value of each pixel takes any value of 256 gradations (see FIG. 6).
(A)). On the other hand, a printer prints an image by forming dots on printing paper, and can take only two states of whether or not to form dots. Most recently, there are printers that can take multiple values including an intermediate state by changing the size of a dot or the like, but there are still few gradation values that can be taken. Therefore, it is necessary to express an image represented by 256 gradations with very few gradation values that can be represented by the presence or absence of dots. The process of performing such conversion is a process called halftoning. FIGS. 6A and 6B are explanatory diagrams illustrating a state in which the halftoning process is performed. FIG. 6A illustrates image data after color conversion before performing the halftoning process, and FIG. The image data after the operation is shown. As shown in the figure, each of the pixels constituting the image before the halftoning process is written with one of the 256 gradation values.
Any value representing whether a dot is formed (ON) or not (OFF) is written.

If the image data having 256 gradations is simply binarized, a predetermined threshold value may be compared with the gradation value of each pixel and binarized according to the magnitude of the value. However, when the image binarized in this way is printed, a contour that does not exist in the original image appears in the printed image, that is, a so-called pseudo contour occurs. To avoid this problem, many methods of halftoning are used. Has been proposed,
Techniques such as the tissue dither method and the error diffusion method are widely used.

When the halftoning process is completed, FIG.
(Step S11).
6). In this process, the data converted into a format representing the presence or absence of dot formation by halftoning is transferred to the printer 2.
This is a process of rearranging the data in the order to be transferred to 0. That is, the printer 20 drives the print head 41 to form dots on the printing paper P while repeating the main scanning and the sub-scanning of the carriage 40 as described above. In the pixel rearrangement process, the image data representing the presence or absence of dots is rearranged in consideration of the movement of the carriage 40 so that the print head 41 forms dots. The image data thus rearranged is output as image data FNL in a format that can be printed by the printer 20, and the data conversion process ends.

C. Color Conversion Conversion from color expression by RGB to color expression by C, M, Y is performed by referring to a conversion table. FIG.
FIG. 4 is an explanatory diagram conceptually showing a conversion table referred to in color conversion. As described above, the computer 80 has the RGB
The image is synthesized to express a color image, and each pixel constituting each image can take a gradation value of 0 to 255.
Therefore, considering a three-dimensional space (RGB color space) having the R, G, and B tone values as axes, all colors represented on the computer have the length of one side as shown in FIG. Can be associated with the coordinates of one point in the cube of 255. This cube is subdivided into small cubes as shown in FIG. 7, and the colors represented by the coordinates of the vertices of the cube are represented by R, G, and
The expression from B is converted into the expression by C, M, Y, and the conversion result is stored for each vertex. In this way, a set of numerical value sets in which the coordinates in the RGB color space are associated with the C, M, and Y gradation values can be created. The color conversion is performed as follows while referring to the conversion table created in this manner.

From the coordinates of each vertex in the RGB color space,
A method for calculating the C, M, and Y gradation values will be described later.
The number of pairs of coordinates in the RGB color space and the C, M, and Y gradation values is the cube of the number of divisions of each side of the cube, and the three coordinate values in the RGB color space for each vertex , C, M, Y. Therefore, it should be added that the number of data constituting the conversion table is large, and the storage of the conversion table requires a very large storage capacity.

By referring to the conversion table, it is possible to easily convert the color expression by R, G, B into the color expression by C, M, Y. As shown in FIG. 7, a case where a color represented by a point A in the RGB color space is converted into a color representation by C, M, Y will be described as an example. First, from among the small cubes subdivided when creating the conversion table, a cube containing point A (dV)
Choose out. Unless point A is on the edge of a small cube, there is only one cube containing point A. When the point A is on the side of the small cube, one arbitrary cube including the point A may be selected. For each vertex of the cube selected in this way, the C, M, and Y tone values are checked with reference to a conversion table created in advance. Next, based on the positional relationship between these vertices and point A in the RGB color space, the C, M, and Y gradation values of each vertex are used to calculate A
The C, M, and Y gradation values at the point may be obtained by interpolation.
Various widely known methods such as linear interpolation can be applied to the interpolation.

Next, a method of calculating the C, M, and Y gradation values from the coordinate values in the RGB color space for each of the vertices of the subdivided small cube will be described. For this calculation, a theory known as Neugebauer theory can be applied, and various methods based on this theory have been proposed.
Further, according to the Neugebauer theory, it is also possible to understand why the conversion table to be referred to may need to be changed depending on the difference in printing resolution of the printing apparatus and the type of printing paper. Therefore, first, an outline of this theory will be briefly described below.

When printing is performed using three colors of C, M, and Y, the ink can be mixed in eight states. That is, C, M, and Y inks exist independently, C and M are mixed, C and Y are mixed, Y and M are mixed, and C, M, and Y are three. There are a total of eight states: a mixed state and a state in which no ink is present. FIG. 8A schematically shows these eight states. When a small area on a printing paper is considered, the color that appears in that area is determined by what proportion these eight states appear and what stimulus value each state has. You can think.

Here, the stimulus value of a color is a numerical value indicating how much reddish, greenish, or bluish sensation is felt from the color. There are three stimulus values of R, G, and B corresponding to each color of red, green, and blue, and each stimulus value can be measured by a direct reading method, a spectroscopic method, or the like.
If one set of stimulus values of R, G, and B is determined, one arbitrary color can be specified.

Therefore, for a very small area on the printing paper, R
Consider finding each of the stimulus values of G and B and specifying the color expressed in the area. The R stimulus value of the micro area is
It can be obtained by adding the weight of the area ratio to each of the R stimulus values of the eight states and integrating them. The G stimulus value and the B stimulus value can be obtained in the same manner. Since the R, G, and B stimulus values for each of the eight states can be measured, the R, G, and B stimulus values can be obtained if the area ratios of the respective states are known.

Neugebauer is based on the assumption that the C, M, and Y color inks are stochastically overlapped. If the dot percentages of the C, M, and Y inks are kc, km, and ky, respectively, the R -It is assumed that the GB stimulation value is obtained by the equation (1).
Here, “probabilistically overlapping” may be considered to indicate a situation in which consideration is not given to avoid overlapping of the respective color inks, and “halftone dot area ratio” refers to a minute area. It may be considered as the area ratio of each color ink occupied. The area ratio of C, M, Y ink is C, M, Y.
Substantially corresponds to each gradation value of.

[0059]

(Equation 1)

Applying Neugebauer's theory, R · G
The color expression by B can be converted to the color expression by C, M, Y. That is, by calculating the formula (1), C, M, M, and C are obtained so that the R, G, and B gradation values of the desired color can be obtained.
What is necessary is just to find one set of Y gradation values. However, since such calculations require a long time, it is impossible to perform such calculations for each pixel and perform color conversion when printing a color image. Therefore, the above-described conversion table is stored, and color conversion is quickly performed by referring to the conversion table.

The reason why the conversion table to be referred to may need to be changed when the printing paper is different and the degree of ink bleeding or the resolution of the printing apparatus is changed can also be understood by Neugebauer's theory. FIG. 8 (a)
FIG. 8B shows a state in which the printing paper is changed to a paper in which ink is more likely to bleed from the state shown in FIG.
Comparing the two figures, it can be seen that the ratio of the eight ink-mixed states changes significantly depending on the difference in the amount of bleeding of the printing paper. In general, the stimulus value of a portion where ink is mixed has a property different from the value obtained by integrating the stimulus values of the single ink, and the color expressed when the degree of ink mixing is different also differs. Therefore, when the printing paper changes and the degree of ink bleeding changes, the conversion table used for color conversion may need to be changed.

The reason why the conversion table may need to be changed when the printing resolution of the printing apparatus is different can be similarly understood. As the printing resolution increases, the number of ink dots formed per minute area increases. However, since the size of the formed dots does not change, when the printing resolution is increased, the area ratio where the ink is mixed increases, and the state is exactly as shown in FIG. 8B. For this reason, a case arises in which the conversion table must be properly used according to the print resolution.

In some cases, it is necessary to use different conversion tables depending on the type of ink used. FIG. 9 is a graph showing the measurement results of the wavelength of light reflected when white light is applied to the ink. FIG. 9A shows the case of ideal ink, and FIG. 9B shows the case of actual ink. Although it is usually assumed that the inks of C, M, and Y have ideal characteristics as shown in FIG. 9A, when actually determining the conversion table, the characteristics of the actual inks are considered. You need to decide. FIG. 9B shows two sets of C ·
The measurement results for each color of the MY ink are shown. The characteristics of yellow (Y) are almost the same, but the characteristics of cyan (C) and magenta (M) are greatly different. When it is conceivable to use a plurality of types of ink as described above, it is necessary to perform color conversion with reference to a conversion table corresponding to the characteristics of the ink.

D. Transfer of Conversion Table in the Embodiment The transfer of the conversion table in the embodiment will be described below. In this embodiment, the computer 80 supplies a conversion table to the data conversion device 10, and the data conversion device 10 converts image data with reference to the conversion table. FIG.
9 is a flowchart illustrating a printing operation performed on the computer side and the data conversion apparatus side regarding the handling of the conversion table. The left side of the figure shows the operation flow of the computer, and the right side of the figure shows the operation flow of the data converter.

When a printing operation is started by the computer 80, first, printing conditions are set (step S20).
0). Here, information such as the printing resolution of the printer 20 that actually performs printing and the type of printing paper is stored in the computer 80.
Inform These conditions are determined by the printer
The setting is performed while looking at the screen of the printer 0, but the printer may be set by the setting panel 18 provided in the printer.
Necessary information may be taken in.

The computer 80 selects a conversion table to be used for color conversion based on the set print information (step S210). The hard disk 84 built in the computer 80 stores various conversion tables corresponding to various printing conditions. As described above, since the conversion table requires a large storage capacity for storage, it is stored in a large-capacity hard disk 84, read out as necessary, stored in the RAMa13, and used for color conversion. The computer 80 stores a correspondence table as shown in FIG. 11 in addition to the conversion table. As shown in the drawing, information such as the accuracy of the conversion table and the presence / absence of compression is stored for each conversion table in addition to the printing resolution, printing paper, image attributes, and the like. The computer 80 refers to the correspondence table, and generates one conversion table suitable for printing conditions.
Choose one.

The selected conversion table is transferred from the computer 80 to the data conversion device 10 (step S22).
0). If the selected conversion table is compressed or if the accuracy of the conversion table is different from the predetermined accuracy, the computer 8
In some cases, the conversion table is decompressed on the 0 side or supplied to the data conversion apparatus 10 after the accuracy of the conversion table is adjusted. When the conversion table is compressed and stored, or when the accuracy of the stored conversion table is low, the storage capacity required for storing the conversion table can be reduced. In addition, if the conversion table is standardized in accuracy by the computer 80 before the conversion table is output to the data conversion apparatus 10, it is not necessary to store the conversion table with the same accuracy in the hard disk 84.

FIG. 12 shows a flowchart of the conversion table output process when the computer 80 decompresses the conversion table and changes the precision. The CPU 81 of the computer 80 determines whether the conversion table selected first is compressed (step S221). This determination is made by referring to the correspondence table shown in FIG. Of course, the presence or absence of compression may be written in the header of the data, and the determination may be made with reference to this. If the conversion table is compressed, it is decompressed (step S222), and then it is determined whether the accuracy of the conversion table matches a predetermined accuracy (step S22).
3). This determination is made by referring to the above-mentioned correspondence table. When the accuracy of the conversion table is low, the data is interpolated so as to have a predetermined accuracy (step S224), and when the accuracy is high, the data is thinned out so as to have the predetermined accuracy (step S225). If data is decompressed or interpolated using a CPU 81 or a large-capacity RAM 83 mounted on the computer 80 and capable of high-speed operation, rapid processing is possible. After these processes are completed, the conversion table is stored in the data conversion device 1.
0 is output (step S226).

As shown in FIG. 10, when the computer 80 outputs the conversion table (step S220), the data conversion device 10 receives and stores it (step S2).
40). The interface 85 of the computer 80 and the input interface 15 of the data converter 10 are connected by a serial or parallel communication cable.
The output conversion table is supplied to the data conversion device 10 through the communication cable.

As shown in FIG. 12, the computer 80
Is performing the decompression or interpolation of the conversion table, the data conversion apparatus stores the received conversion table in the RAMa13 as it is. However, processes such as decompression and interpolation may be performed in the data conversion device 10. In this way, since the conversion table supplied from the computer 80 remains compressed, the data amount is small, and the time required for communication of the conversion table can be shortened. In this case, FIG.
The processing shown in the flowchart of FIG.
Do it in

When the data conversion apparatus 10 completes receiving and storing the conversion table, the computer 80 outputs the image data to be printed (step S230). The image data is also supplied to the data converter 10 via the interface 85 of the computer 80, the communication cable, and the interface 15 of the data converter 10, and is temporarily stored in the RAMa13. The data conversion device 10 converts the image data stored in the RAM a13 with reference to the conversion table sent earlier, and stores the conversion result in the RAM b 14 (step S250). The outline of the data conversion process (step S250) has already been described with reference to FIG.

When the data conversion process is completed, the data conversion device 10 outputs the data stored in the RAM b 14 to the color printer 20 via the output interface 16 (Step S260). According to this data,
The color printer 20 forms C, M, Y, and K dots on printing paper, so that a color image corresponding to a color original can be obtained.

In the embodiment described above, the conversion table corresponding to the image to be printed is sent from the computer 80 to the data conversion device 10, and the data conversion device 10 uses this conversion table to convert the image data. Do. Therefore, since only one conversion table needs to be stored in the data conversion device 10, the capacity of the RAM to be mounted can be saved, and it is possible to avoid an increase in size and cost of the device. Furthermore, a conversion table corresponding to the printing conditions is supplied from the computer 80 to the data conversion apparatus 10, and color conversion is performed with reference to the conversion table, so that high-quality color printing can be performed.

The printing conditions of the conversion table previously output from the computer 80 to the data conversion device 10 are stored, and only when the printing conditions of the image are different from the stored printing conditions, the conversion table is stored. You may make it output to a converter. FIG. 13 shows a flowchart when such processing is performed. In the present embodiment, unlike the embodiment described with reference to FIG. 10, after setting the print conditions (step S200), it is determined whether or not the print conditions match the stored previous print conditions. (Step S
270). If the printing conditions match, the conversion table referenced during the previous data conversion can be used as it is. The conversion table is stored in the RAMa1 of the data conversion device 10.
3 has already been stored, the computer 80 starts image data output without performing processing such as selection and output of a conversion table (step S230). On the other hand, when the printing conditions do not match, it is considered that the conversion table stored in the RAMa13 of the data conversion device 10 does not correspond to the current printing conditions. Therefore, the computer 80 selects an appropriate conversion table (step S21).
0), after outputting this to the data converter 10 (step S220), the new printing conditions are stored in the RAM 83 of the computer 80 (step S280). As the data conversion value 10, the received conversion table is stored in the RAMa13 (step S240), and the image data output from the computer 80 is converted with reference to the conversion table (step S260). This is preferable because it is unnecessary to output the conversion table from the computer 80 when the conversion table in the data conversion apparatus 10 does not need to be rewritten.

Various other methods are available for judging the difference in the printing conditions and supplying the conversion table to the data conversion device 10 only when necessary. FIG. 14 is a flowchart illustrating an example of such a method. In this method, the data conversion device 10 stores the previous print condition and notifies the computer 80 of the condition (step S36).
0). The computer 80 determines the difference between the printing condition notified from the data conversion device 10 and the printing condition of the current printing (step S320). If the printing conditions do not match, the conversion table selection process (step S330) and the conversion table Output processing (step S340) is performed. If the printing condition notified from the data conversion device 10 matches the current printing condition, it is considered that a conversion table suitable for the current printing is already stored in the RAMa13 of the data conversion device 10. Can be Therefore, without selecting or outputting the conversion table,
Output the image data to the data converter (step S3)
50). This is preferable because the conversion table is supplied from the computer 80 only when the conversion table stored in the data conversion apparatus 10 needs to be changed.
Further, in the present embodiment, the printing conditions are stored in the data conversion device 10, and the computer 80 receives the stored printing conditions and determines whether it is necessary to transmit a conversion table. I have. Therefore, even if the data conversion device 10 connected to the computer 80 is connected to another data conversion device after printing a certain image, the necessity of transmitting the conversion table when printing the next image is correctly determined. You can judge.

It is also preferable to determine whether the conversion table needs to be output as shown in FIG. That is, when the printing conditions are set (step S500), the computer 80 notifies the data conversion device 10 of the set printing conditions (step S510). The data conversion device 10 determines the difference between the notified condition and the stored printing condition (step S570), and when both conditions are different, requests the computer 80 to output a conversion table (step S570). Step S580). If the two conditions match, it is considered that the data conversion can be performed with reference to the conversion table stored in the RAMa 13 in the data conversion device 10. Therefore, the data conversion device 10 Start data conversion processing without processing such as output request. When the computer 80 receives the conversion table output request from the data conversion device 10 (step S520), it selects a conversion table corresponding to the printing condition (step S530) and outputs this to the data conversion device 10 (step S540). . If there is no conversion table output request, the computer 8
In step S550, image data output is started immediately without performing processing such as selection and output of a conversion table (step S550). Even in this case, the conversion table can be transmitted only when it is necessary to change the conversion table stored in the data conversion apparatus 10, which is preferable.

Further, when the computer 80 can analyze the image to be printed and determine the image attribute, it is also preferable to use a conversion table according to the image attribute as follows. is there. FIG. 16 shows a flowchart of the printing operation in the computer and the data conversion device in such a case. In the hard disk 84 of the computer 80, the printing resolution of printing paper, the type of printing paper,
Various conversion tables corresponding to combinations of image attributes of print images are stored in advance. When the image printing conditions are set (step S700), the computer 80
A plurality of conversion tables having different image attributes are selected from the stored conversion tables based on the print resolution and the type of printing paper (step S710), and all the selected conversion tables are output to the data conversion device 10. (Step S720). When receiving the conversion table, the data conversion device 10 converts them into RA.
It is stored in Ma13 (step S740). Next, the computer 80 analyzes the image data to be printed, determines the image attribute for each pixel, and outputs the image attribute determination result to the data conversion device 10 in addition to the image data (step S730). When converting the image data, the data conversion device 10 switches the conversion table to be referred to from the conversion table stored in the RAMa13 on a pixel-by-pixel basis based on the determination result of the image attribute (step S750). . This is preferable because data conversion can be performed while referring to a more suitable conversion table according to the attributes of the image.

In one image, the image attributes tend not to appear separately but to be continuous. Therefore, when performing data conversion, instead of selecting a conversion table corresponding to the image attribute for each pixel, only the switching of the image attribute is detected, and only when the switching is performed,
It is preferable to select a conversion table to be referred to, because it speeds up the data conversion process.

In the embodiments described above, the image data is supplied from the computer 80 to the data converter 10. However, the device for supplying the image data is not limited to the computer. For example, FIG.
As shown in FIG. 7, image data is supplied to the data conversion device 10 from various image devices such as a digital camera 22, a color scanner 24, a film scanner 28, and a video printer 26, and the data conversion device 10 converts the image data. An embodiment in which the printer 20 converts the data into a printable data format is also possible. In such an embodiment, the RAMa 13 or the RO
A plurality of conversion tables are stored in M12, and the CPU 11 in the data conversion device 10 selects a corresponding conversion table according to printing conditions. Here, the printing condition may be supplied from the image device to the data conversion device 10 before the image is supplied. However, the printing condition is set in advance by the printer using the setting panel 18 and based on this condition. The CPU 11 may select the corresponding conversion table. CPU11
Converts the supplied image data into a printable data format with reference to the conversion table, and outputs the data to the printer 20. This is preferable because an image captured by an image device such as the digital camera 22 can be printed by the printer 20 without passing through the computer 80.

When the data conversion device 10 does not store an appropriate conversion table, the computer 80 is connected to the data conversion device 10 instead of the image equipment, and the conversion stored in the hard disk 84 of the computer 80 is performed. The table may be overwritten on the RAMa13 of the data conversion device 10. The operation of selecting the conversion table stored in the hard disk 84 and writing it in the RAMa 13 of the data conversion device 10 can be easily realized by using the functions of the operating system running on the computer 80. By doing so, the conversion table can be read from the computer 80 and used as needed, so that the storage capacity of the data conversion device 10 can be saved, which is preferable.

Further, a standard conversion table is stored in the data conversion apparatus 10, and if there is no corresponding conversion table in the RAM 13 or the ROM 12, data conversion is performed with reference to the standard conversion table. It is also preferable to use
FIG. 18 is a flowchart showing the operation of the data conversion device when converting image data received from the digital camera 22 or the like. First, the printing person sets printing conditions using the setting panel 18 of the data conversion device 10 (step S800). The CPU 11 determines whether a conversion table corresponding to the printing condition is stored in the RAMa 13 or the ROM 12 (step S810), and if there is a corresponding conversion table, selects the conversion table (step S8).
20) If there is no corresponding conversion table, a standard conversion table stored in the ROM 12 is selected (step S83).
0). Next, the data format of the image data supplied from the image device is converted with reference to the selected conversion table (step S840), and the converted data is output to the printer 20 (step S850). Here, if an appropriate conversion table is stored in the standard conversion table, an almost satisfactory image can be printed even when the corresponding conversion table is not stored. In the embodiment described with reference to FIG. 18, the data converter 10 is described as receiving data from an image device. However, the present invention is not limited to this. It may be.

The present invention is not limited to the above examples and embodiments, but can be implemented in various modes without departing from the scope of the invention.
For example, in the various embodiments described above, the data conversion device 10 has been described as being externally present separately from the computer 80 and the printer 20. However, they need not be apparently distinct.
For example, various functions of the data conversion apparatus 10 may be incorporated in an expansion board or an expansion card and mounted in an expansion slot of a computer 80 or a printer (see FIG. 19), and may be integrally configured with these. Of course it is good.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a printing apparatus including a data conversion device as an embodiment of the present invention.

FIG. 2 is a schematic explanatory view of a printer used in the present embodiment.

FIG. 3 is an explanatory diagram of a dot forming principle of a printer used in the present embodiment.

FIG. 4 is a flowchart illustrating an outline of a data conversion process according to the embodiment.

FIG. 5 is a conceptual diagram illustrating an outline of an undercolor removal process.

FIG. 6 is a conceptual diagram illustrating an outline of a halftoning process.

FIG. 7 is a conceptual diagram illustrating an outline of a conversion table according to the present embodiment.

FIG. 8 is a conceptual diagram illustrating an outline of Neugebauer theory.

FIG. 9 is a measurement example of spectral characteristics of ink used for color printing.

FIG. 10 is a flowchart illustrating an example of a process according to the present exemplary embodiment.

FIG. 11 is a conceptual explanatory diagram of a correspondence table stored in a computer in the present embodiment.

FIG. 12 is a flowchart illustrating an example of a conversion table output process according to the present embodiment.

FIG. 13 is a flowchart illustrating another example of the processing according to the present exemplary embodiment.

FIG. 14 is a flowchart illustrating another example of the process according to the present embodiment.

FIG. 15 is a flowchart illustrating another example of the processing according to the present exemplary embodiment.

FIG. 16 is a flowchart in a case where data conversion is performed while switching a conversion table according to an image attribute.

FIG. 17 is a block diagram illustrating a case in which image data is supplied from an image device such as a digital camera in the present embodiment.

FIG. 18 is a flowchart when data conversion is performed using a standard conversion table.

FIG. 19 is an explanatory diagram illustrating an example of another aspect of the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Data converter 10 11 ... CPU 12 ... ROM 13 ... RAMa 14 ... RAMb 15, 16 ... Interface 17 ... Bus 18 ... Setting panel 20 ... Printer 22 ... Digital camera 24 ... Color scanner 26 ... Video printer 28 ... Film scanner 30 ... Carriage motor 31 ... Drive belt 32 ... Pulley 33 ... Sliding shaft 34 ... Position detection sensor 35 ... Paper feed motor 36 ... Platen 40 ... Carriage 41 ... Print head 42,43 ... Ink cartridge 44,45,46,47 ... Ink discharge head 48 ... Ink passage 50 ... Control circuit 51 ... Operation panel 80 ... Computer 81 ... CPU 82 ... ROM 83 ... RAM 84 ... Hard disk 85 ... Interface 91 ... Modem

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 2C087 AA15 AB05 AC07 BA03 BA07 BA12 BB10 BD14 BD31 BD36 BD40 BD53 DA16 5B021 AA01 DD00 LG07 5B057 AA11 CA01 CA08 CA12 CA16 CB01 CB08 CB12 CB16 CD05 CE11 CE17 CE18 CH071901 PP20 PP32 PP33 PP37 PQ08 PQ12 PQ23 SS02 TT02 5C079 HB01 HB03 HB12 KA15 KA18 LA31 LA37 LB02 MA04 MA11 NA03 PA03 PA08

Claims (5)

[Claims] 1. A data conversion device for converting image data input from a computer into a data format printable by a printing device while referring to a predetermined conversion table, and outputting the converted data. Storage means for rewritably storing the conversion table supplied from the computer, receiving means for receiving the image data, and receiving means for receiving the image data with reference to the conversion table stored in the storage means. A data conversion device, comprising: a conversion unit for converting the converted image data; and an output unit for outputting a result of the data conversion, and configured separately from the computer. 2. A computer that supplies image data to a data conversion device that converts image data into a format printable by a printing device and outputs the converted image data by referring to a predetermined conversion table. Image data output means for outputting the image data to a data conversion apparatus, conversion table storage means for storing various conversion tables corresponding to image printing conditions, and conversion table storage means A conversion table selecting unit for selecting one of the conversion tables according to an image printing condition; and a conversion table for outputting the selected conversion table to the data conversion apparatus prior to the conversion of the image data. A computer comprising an output unit, and configured separately from the data conversion device. 3. The computer according to claim 2, wherein the conversion table selection unit is a unit that selects the conversion table according to at least a printing resolution of a printing apparatus and a type of printing paper. 4. A data conversion device for converting image data input from an image device such as a digital camera or a color scanner into a data format printable by a printing device with reference to a predetermined conversion table and outputting the converted data. Conversion table storage means for storing various conversion tables corresponding to image printing conditions; and one of the conversion tables stored in the conversion table storage means according to image printing conditions. A conversion table selecting unit for selecting one of the two; a receiving unit for receiving the image data; a conversion unit for converting the image data received by the receiving unit while referring to the conversion table selected by the conversion table selecting unit; An output unit that outputs a result of the data conversion, wherein the data conversion device is configured separately from the image device. 5. A data conversion method for converting image data output from a computer into a data format printable by a printing device with reference to a predetermined conversion table and outputting the converted data. A conversion table corresponding to the printing conditions of the image is selected from the various conversion tables set in advance, and the selected conversion table can be rewritten to a data conversion device provided separately from the computer. A data conversion method for storing and converting image data supplied from the computer with reference to the stored conversion table.