JP2003291314A - Monotone printing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for stably carrying out monotone printing which gives various kinds of color sensation. <P>SOLUTION: Monotone printing which gives various kinds of color sensation is carried out by adjusting an ink discharge amount of a blackish-group ink and a chromatic ink with a predetermined hue. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for performing monotone printing of images.

[0002]

2. Description of the Related Art In recent years, color ink jet printers have become widespread as image printing apparatuses. Ordinary color inkjet printers use black ink (K)
And a plurality of types of ink having hues of cyan (C), magenta (M), and yellow (Y). High-quality color printing is realized by reproducing an arbitrary color of a color image using these plural kinds of ink.

While color printing is widely used, monotone images used in silver halide photography are also widely favored. Even when printing an image with a printer, monotone printing (monotone printing) is often performed. is there.
The monotone expression is not limited to an expression that reproduces gradation using pure achromatic colors (so-called neutral expression), and there are expressions with various tints. For example, there are various expressions such as warm expression that expresses gradation using yellowish gray and cool expression that expresses gradation using bluish gray, which gives various hues such as yellow and blue. Furthermore, even with the same hue, there are expressions such as light yellow and dark yellow, light blue and dark blue, which give different color sensations with different saturations. Conventionally, even in the case of performing monotone printing having such various color feelings, the color feelings are reproduced by using a plurality of types of CMYK inks.

[0004]

In the conventional color ink jet printer, various color feelings used in monotone printing are reproduced by combining a plurality of usable inks. For example, when reproducing a cool expression, blue was reproduced by combining cyan ink and magenta ink in addition to black ink.

Here, if there is a variation in the ejection amount of each ink, the reproduced color appearance will deviate from the desired color appearance. For example, when the ejection amount of magenta ink exceeds a predetermined amount, a purple-like cool expression is obtained. Human color vision is very sensitive to differences in hue in regions near gray. Therefore, such a slight shift in the color appearance is perceived as a very large shift. As described above, when performing monotone printing, there is a problem in that the reproduced color feeling tends to be unstable.

The present invention has been made to solve the above-mentioned problems in the prior art, and an object of the present invention is to provide a technique for stably performing monotone printing that gives various color sensations.

[0007]

In order to solve the above problems, the first invention of the present invention is a printing apparatus for performing monotone printing of an image by ejecting ink onto a printing medium. Therefore, one monotone print mode is selected from a print head capable of ejecting a black ink and a first chromatic color ink having a predetermined hue and a plurality of monotone print modes having different color sensations. A print mode selection unit that allows the user to
An adjustment unit that adjusts the ejection amounts of the black-based ink and the first chromatic color ink so as to reproduce the color appearance of the monotone print mode selected by the print mode selection unit.

Since the printing apparatus according to the present invention reproduces the color appearance of the selected monotone printing mode by adjusting the ejection amounts of the two types of ink, the black ink and the first chromatic ink. There is an advantage that the number of kinds of ink to be adjusted is smaller than that in the case of reproducing the color appearance by the balance of the ejection amounts of the four types of CMYK inks, and the stability of the reproduced color appearance can be improved.

In the above printing apparatus, it is preferable that the black ink has a hue having a complementary color relationship with the first chromatic color ink.

In this way, there is an advantage that the neutral expression can be reproduced by adjusting the ejection amounts of the black ink and the first chromatic color ink. Furthermore, there is an advantage that two types of monotone expressions having different hues can be reproduced by adjusting the ejection ratios of the black ink and the first chromatic color ink. In addition, even if there are variations in the ejection amount of each ink, the reproduced hue does not change,
There is an advantage that a desired color appearance can be reproduced more stably.

In each of the above printing apparatuses, it is preferable that the black ink is composed of a plurality of types of black ink having substantially the same hue and different densities.

In this way, in a relatively bright area, the number of ink dots can be increased by using ink with a low density. Therefore, there is an advantage that the smaller the number of ink dots, the more noticeable the graininess (roughness of the image) can be improved. Moreover, in a relatively dark region, the number of ink dots can be limited by using high-density ink. Therefore, there is an advantage that it is possible to suppress banding (streak-like image quality deterioration), which tends to stand out when the number of ink dots is large.

When comparing the densities of a plurality of types of ink, the same amount of ink is ejected onto the same print medium,
A method of measuring the concentration using a densitometer for each can be used.

In each of the above-mentioned printing apparatuses, the print head can further eject at least one second chromatic color ink for at least one hue different from the hue of the first chromatic color ink, In each of the plurality of monotone print modes, the adjustment unit may reduce the second chromatic ink amount by a smaller amount than the first chromatic color ink ejection amount in the monotone print mode in which the first chromatic color ink ejection amount is the largest. It is preferable to finely adjust the color appearance of the printed image by ejecting chromatic ink.

By doing so, even if there are variations in the colors of the inks that can be used or the print medium has a tint, the second chromatic color inks are used to make the reproduced color feeling smaller. It has the advantage of being adjustable.
Further, by suppressing the ejection amount of the second chromatic color ink to be smaller than the ejection amount of the first chromatic color ink in the monotone printing mode in which the ejection amount of the first chromatic color ink is the largest, the black ink It is possible to adjust the color appearance without significantly changing the color appearance reproduced with the first chromatic color ink. That is, there is an advantage that a desired color appearance can be stably reproduced. Furthermore, the number of ink dots can be increased by replacing a part of the black ink with a plurality of types of ink for printing. Therefore, the smaller the number of ink dots, the more conspicuous the graininess can be improved.

In each of the above-mentioned printing apparatuses, the adjusting section is
In each of the plurality of monotone print modes,
It is preferable to finely adjust the color appearance of the print image by ejecting the second chromatic color ink in an amount smaller than the ejection amount of the first chromatic color ink in the almost achromatic color monotone print mode.

By doing so, it is possible to adjust the color appearance without greatly changing the color appearance reproduced by the black ink and the first chromatic color ink. That is, there is an advantage that a desired color appearance can be stably reproduced.

In each of the printing apparatuses, it is preferable that the ejection amount of the second chromatic color ink does not depend on the monotone printing mode.

By doing so, when finely adjusting the shift in color appearance due to the color of the print medium or when improving the graininess of the printed image, the result of fine adjustment of the ink discharge amount performed for one monotone print mode Can be applied to other print modes.

In each of the printing apparatuses, it is preferable that the second chromatic color ink is an ink having a lower density than the first chromatic color ink.

By doing so, even if the ejection amount of the second chromatic color ink or the color of the second chromatic color ink varies, it is determined by the black ink and the first chromatic color ink. There is an advantage that the color appearance can be reproduced without significantly changing the color appearance. Furthermore, in a relatively bright region, there is an advantage that the graininess can be further improved by reproducing using a thin ink.

In each of the printing apparatuses, the print head can eject a plurality of dark and light inks having substantially the same hue but different densities as the second chromatic color ink, and the adjusting section is a monotone. It is preferable to use an ink having a relatively low density among the plurality of dark and light inks at the time of printing.

By doing so, a printer that can use a plurality of dark and light inks having almost the same hue but different densities,
For example, there is an advantage that monotone printing can be performed using a color printer. Further, by using the light ink during the monotone printing, even if the ejection amount of the second chromatic ink or the color of the second chromatic ink varies, the black ink and the first ink
There is an advantage that the color appearance can be reproduced without largely changing the color appearance determined by the chromatic color ink. Furthermore, in a relatively bright region, there is an advantage that the graininess can be further improved by reproducing using a thin ink.

In each of the above-mentioned printing devices, the adjusting section is
The conversion from the first image data represented by the first color system to the second image data represented by the second color system composed of the ink that can be used in the printing device is referred to as a look. An ink amount data conversion unit that uses an up table and a plurality of look-up tables prepared corresponding to the plurality of monotone printing modes are provided, and the ink amount data conversion unit selects the selected monotone printing mode. It is preferable to select and use a lookup table corresponding to the mode.

By doing so, there is an advantage that the process of converting the image data into the ink amount data can be performed quickly by referring to the lookup table. In addition, a look-up table corresponding to the color appearance of multiple monotone print modes is provided, and the look-up table corresponding to the color appearance of the selected monotone print mode is selected and used from the look-up table. There is an advantage that it is possible to perform monotone printing according to the above.

In each of the above printing devices, the first chromatic color ink is preferably a yellow ink.

This has the advantage that the warm expression, which is often used in monotone images, can be reproduced. Further, since the yellow ink is an ink that is also used in a normal color printer, there is an advantage that the yellow ink for color printing and the yellow ink for monotone printing can be shared.

In each of the printers, the plurality of monotone print modes are nearly achromatic, including a warm mode in which the hue of the entire image is biased to yellow, a cool mode in which the hue of the entire image is biased to blue. And a neutral mode.

There is an advantage that the convenience can be improved by supporting the monotone print mode preferred by these users.

The present invention can be implemented in various forms, for example, a printing method and a printing device,
Print control method and print control apparatus, computer program for realizing functions of these methods or apparatuses,
It can be realized in the form of a recording medium recording the computer program, a data signal including the computer program and embodied in a carrier wave.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described in the following order based on Examples. A. Device configuration: B1. Example 1: B2. Example 2: B3. Example 3: C1. Modification 1: C2. Modification 2: C3. Modification 3:

A. Device Configuration: FIG. 1 is a block diagram showing the configuration of a printing system as an embodiment of the present invention.
This printing system includes a computer 90 as a print control device and a printer 20 as a printing unit. The printer 20 and the computer 90 can be called a “printing device” in a broad sense.

In the computer 90, the application program 9 is executed under a predetermined operating system.
5 is working. The operating system includes a video driver 91 and a printer driver 9 as an adjusting unit.
6 is installed, and application program 9
From 5, the print data PD to be transferred to the printer 20 is output via these drivers. The application program 95 that performs image retouching or the like performs desired processing on the image to be processed, and also displays the image on the CRT 21 via the video driver 91.

When the application program 95 issues a print command, the printer driver 9 of the computer 90
6 receives the image data from the application program 95 and converts it into print data PD to be supplied to the printer 20. In the example shown in FIG. 1, the printer driver 96 includes a resolution conversion unit 97 and a brightness conversion unit 1 inside.
01, an ink amount data conversion unit 98, a halftone processing unit 99, a print data generation unit 100, a lookup table 102, and a print mode selection unit 103. Here, the image data received by the printer driver 96 may be either color image data or monochrome image data.
Description will be made assuming that color image data composed of three color component data B is received.

The resolution converter 97 plays a role of converting the resolution (that is, the number of pixels per unit length) of the color image data formed by the application program 95 into the print resolution.

The lightness conversion unit 101 extracts lightness information from the resolution-converted image data and converts the image data into lightness data representing the lightness of the image. Specifically, R, G,
The brightness data can be obtained by adding the gradation values of the data of each color B. Of course, the extraction of the brightness information can be performed by using other well-known methods. For example, R, G,
It is also possible to obtain the brightness data by adding different weights to the gradation values of the data of each color of B and adding them.
The image data received by the printer driver 96 is
If the image data is the image data in which the lightness information is separated, as in the case of a monochrome image or a color image represented by the L * a * b * color system, processing by the lightness conversion unit 101, or The brightness conversion unit 101 itself can be omitted.

The ink amount data conversion unit 98 refers to the look-up table 102 and sets the brightness data (first image data) of each pixel to a multi-level data corresponding to the amount of a plurality of inks available to the printer 20. Convert to key data (second image data). In the present embodiment, the ink amount data conversion unit 98 is configured to process the image data converted by the brightness conversion unit 101, but by preparing the lookup table 102 including the brightness conversion. It is also possible to convert the resolution-converted image data as the first image data into the second image data.

A plurality of look-up tables 102 are prepared corresponding to a plurality of monotone print modes selectable by the print mode selection unit 103. The ink amount data conversion unit 98 selects and refers to the look-up table corresponding to the color appearance of the selected monotone print mode from the plurality of look-up tables. The types of monotone print modes and types of ink that can be selected, the ink amount data conversion unit 98, and the lookup table 102 will be described later.

The ink amount data has a gradation value of 256 gradations, for example. The halftone processing unit 99 executes so-called halftone processing to generate halftone image data from the ink amount data. This halftone image data is output to the printer 2 by the print data generation unit 100.
The data is rearranged in the order of data to be transferred to 0, and is output as final print data PD. The print data PD
Includes raster data indicating a dot recording state during each main scan and data indicating a sub-scan feed amount.

The printer driver 96 corresponds to a program for realizing the function of generating the print data PD. The program for realizing the functions of the printer driver 96 is supplied in the form recorded in a computer-readable recording medium. Examples of such a recording medium include a flexible disk, a CD-ROM, a magneto-optical disk, an IC card, a ROM cartridge, a punch card, a printed matter on which codes such as a bar code are printed, and an internal storage device (RAM, ROM, etc.) of a computer. memory)
Also, various computer-readable media such as an external storage device can be used.

FIG. 2 is a schematic block diagram of the printer 20. The printer 20 includes a sub-scan feed mechanism that conveys the print paper P in the sub-scan direction by the paper feed motor 22, and a carriage motor 24 that moves the carriage 30 to the platen 26.
Main-scan feed mechanism that reciprocates in the axial direction (main-scan direction), and the print head unit 6 mounted on the carriage 30.
A head drive mechanism that drives 0 to control ink ejection and dot formation, and a control circuit 40 that controls signals with the paper feed motor 22, carriage motor 24, print head unit 60, and operation panel 32. I have it. The control circuit 40 is connected to the computer 90 via the connector 56.

The sub-scan feed mechanism for conveying the printing paper P is
A gear train (not shown) that transmits the rotation of the paper feed motor 22 to a platen 26 and a paper transport roller (not shown) is provided. Further, the main scanning feed mechanism for reciprocating the carriage 30 is provided in parallel with the axis of the platen 26, and a drive shaft 36 which is endless between the slide shaft 34 which slidably holds the carriage 30 and the carriage motor 24. And a position sensor 39 for detecting the origin position of the carriage 30.

FIG. 3 is a block diagram showing the configuration of the printer 20 centering on the control circuit 40. Control circuit 40
Is a CPU 41 and a programmable ROM (PROM)
43, a RAM 44, and a character generator (CG) 45 that stores a dot matrix of characters, and is configured as an arithmetic logic operation circuit. This control circuit 4
Further, 0 is an I / F dedicated circuit 50 dedicated to interface with an external motor and the like, and a head drive circuit 52 connected to the I / F dedicated circuit 50 for driving the print head unit 60 to eject ink. And the paper feed motor 2
2 and a motor drive circuit 54 that drives the carriage motor 24. The I / F dedicated circuit 50 has a built-in parallel interface circuit and has a connector 56.
Print data P supplied from the computer 90 via the
Can receive D. The circuit incorporated in the I / F dedicated circuit 50 is not limited to the parallel interface circuit, but can be determined in consideration of ease of connection with the computer 90 such as a universal serial bus interface circuit. The printer 20 executes printing according to the print data PD. The RAM 44 functions as a buffer memory for temporarily storing the raster data.

The print head unit 60 includes the print head 2
In addition, an ink cartridge of available ink can be mounted. The print head unit 60 is attached to and detached from the printer 20 as one component.
That is, when replacing the print head 28,
The print head unit 60 will be replaced. Nozzles for ejecting usable ink are provided on the lower surface of the print head 28. The nozzle will be described later.

The printer 20 having the above-described hardware configuration conveys the print paper P by the paper feed motor 22 and reciprocates the carriage 30 by the carriage motor 24, and at the same time drives the piezo element of the print head 28. , Each ink droplet is ejected to form an ink dot to form a monotone image on the printing paper P.

B1. Example 1: This example is constructed using the printing system described above. Hereinafter, the types of ink and nozzles used in this embodiment will be described, and then the color appearance, the ink amount data conversion unit, and the look-up table will be described.

FIG. 4 is an explanatory diagram showing the arrangement of the nozzles “Nz” on the lower surface of the print head 28. Print head 2
A nozzle group for ejecting the black ink “K” and a nozzle group for ejecting the yellow ink “Y” as the first chromatic color ink are formed on the lower surface of 8. The black ink “K” has a hue of blue which is a complementary color of yellow.

FIG. 5 is an explanatory diagram showing an example of ink components of the black ink "K" and the yellow ink "Y". As shown in FIG. 5, the ink of each color is based on distilled water, a coloring material composed of various dyes or pigments for imparting a desired color, and a mixed solution in which an appropriate amount of diethylene glycol for viscosity adjustment is added. is there.

In the yellow ink "Y" of this embodiment,
Like the yellow ink used in conventional color printers, Direct Yellow 2 is added. Further, hood black 1 which is a coloring material used for ordinary black ink and cobalt blue 3 which is a coloring material used for blue ink are added to the black ink “K”. The black ink exhibits a bluish black color due to these coloring materials. As described above, it is preferable that the black ink is a mixture of a normal black ink and a coloring material used for the blue ink, for example, cobalt blue. It is also possible to use a mixture of a normal black ink, a coloring material used for cyan ink, for example, direct blue, and a coloring material used for magenta ink, for example, acid red, in predetermined amounts. By doing so, it is possible to use the color material of the ink used in the conventional color printer.

Since the hues of the black ink and the yellow ink have a complementary color relationship, an achromatic print image can be reproduced by adjusting the ejection amounts of these two types of ink. If the ejection ratio of the yellow ink is further increased from here, a slightly yellow hue can be provided, and if the ejection ratio of the yellow ink is reduced, a slightly blue hue can be provided. In this way, by adjusting the ejection ratios of the two types of ink, it is possible to reproduce two types of hues, yellow and blue, in addition to the achromatic color. By using these hues, so-called warm expression (yellow), neutral expression (achromatic color), and cool expression (blue) can be reproduced.

FIG. 6 is a graph for explaining the relationship between the gradation of lightness and the ejection amount of each ink. In FIG. 6, (a)
Indicates a warm expression, (b) indicates a neutral expression, and (c) indicates a discharge amount of each ink in a cool expression, “K” indicates a discharge amount of black ink, and “Y” indicates a discharge amount of yellow ink. . The horizontal axis is the gradation of lightness. The brightness is "255" when it is the brightest (pure white), and "0" when it is the darkest (pure black). The vertical axis represents the ink ejection amount. This ejection amount means the ejection amount when the maximum ink amount that can be ejected per pixel is 100%, and is defined for each ink. The ejection amount of each ink will be described below.

The brightness of the reproduced image is mainly determined by the ejection amount of black ink. Therefore, the ejection amount of the black ink “K” is large in the low lightness region and small in the high lightness region. On the other hand, the hue and saturation of the reproduced image are determined by the ejection ratio of the black ink and the yellow ink. In the low lightness region, the ejection amount of the black-based ink increases, and the influence of the yellow ink weakens. In the high lightness region, the ejection amount of the black ink is small, so that the influence of the yellow ink is strong. Therefore, in a region having a relatively high lightness, the ejection ratio of the black ink and the yellow ink is adjusted to an appropriate value, and in a region having a low lightness, the ejection amount of the yellow ink is adjusted to be small. Here, the ejection amount of the yellow ink is preferably smaller than the ejection amount of the black ink. By doing so, it is possible to prevent the time required for the ink from drying to become long and the print medium from wavy due to the large amount of ink.

The ejection ratio of the black ink and the yellow ink is determined by the color sensation of the monotone print mode to be reproduced. FIG. 6B shows the ejection amount when reproducing the neutral expression which is an achromatic color. The ejection amount is adjusted so that the result of color mixing of the black ink and the yellow ink at each lightness is an achromatic color.

FIG. 6A shows the ejection amount when reproducing the warm expression in which the hue is yellow. Since the ejection rate of yellow ink is higher than that in the case of neutral expression, it is possible to reproduce a yellowish color appearance. The ejection rate of the yellow ink can take various values in a range larger than that in the case of the neutral expression. For example, it is possible to reproduce a light warm expression with a low yellow ink discharge rate and low saturation, and a dark warm expression with a high yellow ink discharge rate and high saturation.

FIG. 6C shows the ejection amount when reproducing the cool expression in which the hue is blue. Since the ejection rate of the yellow ink is smaller than that in the neutral expression, it is possible to reproduce a bluish color impression. The ejection ratio of the yellow ink can take various values in a range smaller than that in the neutral expression. For example, it is possible to reproduce a light cool expression with a high yellow ink discharge rate and low saturation, and a dark cool expression with a low yellow ink discharge rate and high saturation.

This embodiment has an advantage that the reproduced color appearance does not change much even when the ink ejection amount varies. For example, consider the case of reproducing a warm expression. Even if the ejection rate of the yellow ink increases due to the variation in the ejection amounts of the two types of ink,
The hue to which human color vision responds sensitively remains unchanged at yellow. Even if the ejection rate of the yellow ink decreases, the hue remains yellow and remains unchanged. Similarly, when the cool expression is reproduced, even if there are variations in the ejection amounts of the two types of ink, the hue remains blue and remains unchanged. In this way, even if there is a variation in the ink ejection amount, the color appearance can be reproduced stably.

Next, the ink amount data converter 98 (FIG. 1) in this embodiment will be described. The ink amount data conversion unit 98 includes a plurality of prepared lookup tables 1
02, the lightness data of the image (first image data) of each ink is selected by referring to the look-up table 102 corresponding to the color appearance of the monotone print mode selected by the print mode selection unit 103. It is converted into multi-tone data (second image data) corresponding to the amount. The look-up table 102 is a table in which the gradation values of the ink amounts for the gradation values of the lightness are stored, and by referring to this table, the gradation values of the black-based ink are calculated from the gradation values of the lightness. And the ink amount gradation value of the yellow ink can be determined. Lookup table 1 like this
By performing data conversion with reference to No. 02, desired monotone printing can be performed quickly. Here, the gradation of the lightness and the ink amount is subdivided into 256 levels, and 0 or more and 2
It takes a value of 55 or less. By doing so, high-quality monotone printing can be performed. The brightness gradation and the ink amount gradation are not limited to 256 levels. Higher quality monotone printing can be performed by increasing the number of stages, for example 512, and recording medium necessary for recording the lookup table by decreasing the number of stages, for example, 128. The size of can be reduced.

The ink amount data conversion unit 98 can also be configured to convert the image data from the resolution conversion unit 97 into each ink amount data as the first image data. In this case, the look-up table is a table that stores the gradation value of each ink amount for each gradation value of RGB,
By referring to this table, the ink amount gradation value of the black ink and the ink amount gradation value of the yellow ink can be determined from the three gradation values of RGB. In addition,
The first image data is not limited to image data composed of three color components of RGB, but image data of various color systems such as L * a * b * color system and XYZ color system can be used. 1
Can be used as image data.

Next, the relationship between the monotone print mode and the look-up table will be described. A plurality of look-up tables 102 are prepared corresponding to the color appearance of a plurality of selectable monotone printing modes. For example, when it is possible to select three types of print modes: warm expression, neutral expression, and cool expression, (a) in FIG.
(B) Three types of lookup tables having the structures shown in (c) are prepared. When the warm mode is selected by the print mode selection unit 103, the ink amount data conversion unit 9
8 is one of a plurality of look-up tables.
By selecting and referring to the lookup table having the structure of (a), it is possible to perform monotone printing that gives a desired color impression.

The monotone print modes that can be selected are not limited to the three types described above, and it is possible to select print modes that give various color impressions with different saturations. For example,
A neutral expression, a three-step warm expression, and a three-step cool expression may be selectable. In this case, it is preferable to prepare seven types of look-up tables corresponding to selectable print modes. Also, warm expression,
It is also possible to continuously change the saturation of the cool expression so that the color feeling can be selected. FIG. 7 is an explanatory diagram showing how the print mode to be printed is set in the print mode selection unit 103 of the printer driver 96 from the CRT 21. As shown in the figure, when the print mode selection screen of the printer driver 96 is opened, a screen for setting the color appearance is displayed. By moving the arrow displayed on the screen to an appropriate position, it is possible to select a monotone print mode that reproduces a desired color appearance. When there are many types of selectable monotone print modes, the number of lookup tables 102 to be prepared can be limited. If the look-up table 102 corresponding to the selected color appearance does not exist, the values of the plurality of look-up tables 102 corresponding to the color appearance close to the color appearance are interpolated to obtain the ink amount gradation value. Is preferred.

B2. Second Embodiment FIG. 8 is an explanatory diagram showing an arrangement of nozzles “Nz” on the lower surface of the print head 28 in the second embodiment. On the lower surface of the print head 28, a nozzle group for ejecting three types of black inks “K1”, “K2”, and “K3” and a yellow ink “Y” as the first chromatic color ink is formed. .

The yellow ink “Y” is the same as that in the first embodiment. Three types of black ink "K1" and "K2"
“K3” has almost the same hue and has a blue hue that is a complementary color of yellow. Also, these three types of black-based inks have different densities from each other, and the three types of ink, dark black ink “K1”, medium black ink “K2”, and light black ink “K3” are black in order from dark ink. Used as a system ink.

FIG. 9 shows black inks "K1" and "K".
FIG. 6 is an explanatory diagram showing an example of ink components of 2 ”and“ K3 ”and yellow ink“ Y ”. For all three types of black ink, Hood Black 1 and Cobalt Blue 3
And are added, and the addition ratio of these coloring materials is almost the same regardless of the ink. In addition, the addition amount of these color materials is largest in the “K1” ink, and the addition amount of the color materials decreases in the order of the “K2” ink and the “K3” ink.

Black ink and yellow ink "Y"
Since the hues of and are in a complementary color relationship, as in the case of the above-described first embodiment, by adjusting the ejection amounts of these four types of ink, warm expression (yellow), neutral expression (achromatic color), cool expression The expression (blue) can be reproduced.
Further, even if there is a variation in the ejection amount of each ink, the color feeling can be reproduced stably.

FIG. 10 is a graph for explaining the relationship between the gradation of lightness and the ejection amount of each ink in this embodiment. In FIG. 10, (a) shows the discharge amount of each ink in the warm expression, (b) the neutral expression, and (c) the cool expression, “K1” is the discharge amount of the dark black ink, and “K2” is the medium black. Ink ejection amount, “K3” indicates a light black ink ejection amount, and “Y” indicates a yellow ink ejection amount. The definitions of the horizontal axis and the vertical axis are the same as those in the graph of FIG.

The black ink is composed of three types of ink having different densities. Therefore, it is possible to perform higher quality monotone printing by properly using the ink having an appropriate density according to the brightness of the image to be reproduced. In a relatively bright region, the graininess can be improved by using a low density light black ink. In a relatively dark region, banding can be suppressed by using high-density dark black ink. In the intermediate area of the lightness gradation level, by using the medium density medium black ink, the dark ink and the light ink can be smoothly switched. The types of black ink are not limited to three types. For example, even if the black ink is composed of two types of dark black ink and light black ink,
It is possible to improve graininess and suppress banding. Further, by using four or more types of black ink, it is possible to reproduce the brightness gradation more smoothly.

In this embodiment, the ink amount data conversion unit 98 and the look-up table 102 in FIG. 1 are the same as those in the first embodiment. It should be noted that both the ink amount data conversion unit 98 and the lookup table 102 are expanded so as to be able to handle data relating to the black-based ink increased to three types.

B3. Third Embodiment FIG. 11 is an explanatory diagram showing an arrangement of nozzles “Nz” on the lower surface of the print head 28 in the third embodiment. On the lower surface of the print head 28, black inks “K1”, “K2” and “K3”, a yellow ink “Y” as a first chromatic color ink, a cyan ink “lc” and a magenta ink as a second chromatic color ink. A nozzle group for ejecting "lm" is formed. The yellow ink “Y” and the three types of black inks “K1”, “K2”, and “K3” are the same as those in the second embodiment.

FIG. 12 shows the black inks "K1" and "K".
2 is an explanatory diagram showing an example of ink components of “2”, “K3”, yellow ink “Y”, cyan ink “lc”, and magenta ink “lm”. The three types of black ink and yellow ink have the same composition as in the case of Example 2 described above. Similar to the cyan ink used in the conventional color printer, direct blue is added to the cyan ink “lc”. Acid red is added to the magenta ink “lm”, similar to the magenta ink used in the conventional color printer. As these yellow ink “Y”, cyan ink “lc”, and magenta ink “lm”, inks used in conventional color printers can be used.

The cyan ink “lc” and the magenta ink “lm” have different hues from each other, and are different from the hue of the black ink and the hue of the yellow ink. Therefore, a gray color that can be reproduced only with black ink can be reproduced using three types of ink, yellow ink, cyan ink, and magenta ink. As described above, the gray color reproduced by using the three types of ink is generally called “composite black”.
In this embodiment, a part of the black ink necessary for printing is replaced with composite black to increase the number of ink dots and improve the graininess of the printed image.

FIG. 13 is a graph for explaining the relationship between the gradation of lightness and the ejection amount of each ink in this embodiment. In FIG. 9, (a) shows the discharge amount of each ink in the warm expression, (b) the neutral expression, and (c) the cool expression, “K1” is the discharge amount of dark black ink, and “K2” is medium black. Ink ejection amount, “K3” indicates light black ink ejection amount, “Y” indicates yellow ink ejection amount, “lc” indicates cyan ink ejection amount, and “lm” indicates magenta ink ejection amount. The definitions of the horizontal axis and the vertical axis are the same as those in the graph of FIG.

The ejection amount of ink in various monotone print modes is almost the same as that of the above-described second embodiment, but this embodiment is different from the second embodiment in that a part of the black ink is composite black, that is, yellow. Replaced with ink, cyan ink, and magenta ink.

The ejection amount of cyan ink or magenta ink is smaller than the ejection amount of yellow ink for neutral expression (almost achromatic color monotone printing mode). Therefore, the graininess of the printed image can be improved without significantly changing the color appearance reproduced by the black ink and the yellow ink. Further, in the third embodiment, the ejection amounts of the cyan ink “lc” and the magenta ink “lm” are set to values that do not depend on the monotone print mode. Therefore, the effect of improving the graininess performed in one monotone print mode can be applied to another monotone print mode.

The cyan ink "lc" and the magenta ink "lm" are lighter in density than the yellow ink "Y". Therefore, even if the ejection amount or color of the cyan ink “lc” or the magenta ink “lm” varies, it is possible to prevent the color feeling determined by the black ink and the yellow ink from significantly changing. If it is possible to use inks having almost the same hue but different densities, such as a conventional color printer, for example, dark cyan ink and light cyan ink, or dark magenta ink and light magenta ink, It is preferable to utilize a thin light ink. By doing this, even if there are variations in the ejection amount or color of the cyan ink or magenta ink,
It is possible to prevent the color feeling determined by the black ink and the yellow ink from greatly changing.

In this embodiment, the graininess of the printed image is improved by using the second chromatic color ink, but the color feeling can be adjusted by using the second chromatic color ink.
For example, when the color of the yellow ink has a yellowish green hue, even if an attempt is made to reproduce the neutral expression with the three types of black ink and the yellow ink, the color becomes greenish. Therefore, by using an appropriate amount of cyan ink and magenta ink, the hue of the printed image can be adjusted to an achromatic color. Further, even when the print medium is not white but has a tint, the color appearance can be adjusted. For example, when a neutral expression is desired to be reproduced on a thin vermilion print medium, the user specifies that cyan ink should be used in an appropriate amount, and desired monotone printing can be performed. In such cases,
The ejection amounts of cyan ink and magenta ink may be changed according to the monotone print mode. However, as described above, if the ejection amounts of the cyan ink and the magenta ink are set to a value that does not depend on the monotone print mode, for example, fine adjustment of the color appearance according to the tint of the print medium can be performed for a plurality of monotone prints. The adjustment amount common to the modes can be executed.

The type of the second chromatic color ink is not limited to the two types of cyan ink and magenta ink. When the composite black is not used, it is preferable to use the predetermined one kind of the second chromatic color ink. By doing so, it is possible to perform a predetermined color appearance adjustment without increasing the cost. It is also preferable to use three or more types of second chromatic ink. By doing so, it is possible to perform finer adjustment of the color appearance.

In this embodiment, the configuration of the ink amount data converter 98 and the lookup table 102 in FIG. 1 is the same as that of the second embodiment. It should be noted that both the ink amount data conversion unit 98 and the look-up table 102 are expanded to handle data relating to the second chromatic color ink.

The present invention is not limited to the above-described embodiments, but can be implemented in various forms without departing from the scope of the invention. For example, the following modifications are possible.

C1. Modification 1: In the above-described embodiment, printing is performed using a lookup table, but the present invention can be applied to a printing method or printing apparatus that does not use such a lookup table.

C2. Modification 2: The present invention is also applicable to a drum scan printer. The present invention can be applied not only to a so-called inkjet printer, but also to a printing apparatus that prints an image by ejecting ink from a print head. Examples of such a printing device include a facsimile device and a copying device.

C3. Modification 3: In the above-described embodiment, a part of the configuration realized by hardware may be replaced with software, and conversely, a part of the configuration realized by software may be replaced with hardware. May be. For example, a part of the functions of the printer driver 96 (FIG. 1) can be executed by the control circuit 40 (FIG. 3) in the printer 20.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a printing system as an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a printer.

FIG. 3 is a block diagram showing a configuration of a control circuit 40 in the printer 20.

FIG. 4 is an explanatory diagram illustrating a nozzle array on a lower surface of the print head 28 according to the first embodiment.

FIG. 5 is an explanatory diagram illustrating components of ink included in the printing apparatus according to the first embodiment.

FIG. 6 is an explanatory diagram showing a relationship between lightness gradation and ink discharge amount gradation in the first embodiment.

FIG. 7 is an explanatory diagram illustrating an example of setting a monotone print mode.

FIG. 8 is an explanatory diagram showing a nozzle array on the lower surface of the print head according to the second embodiment.

FIG. 9 is an explanatory diagram illustrating components of ink included in the printing apparatus according to the second embodiment.

FIG. 10 is an explanatory diagram showing a relationship between lightness gradation and ink discharge amount gradation in the second embodiment.

FIG. 11 is an explanatory diagram showing a nozzle array on the lower surface of the print head according to the third embodiment.

FIG. 12 is an explanatory diagram illustrating components of ink provided in the printing apparatus according to the third embodiment.

FIG. 13 is an explanatory diagram showing a relationship between lightness gradation and ink discharge amount gradation in the third embodiment.

[Explanation of symbols]

20 ... Printer 21 ... CRT 22 ... Paper feed motor 24 ... Carriage motor 26 ... Platen 28 ... Print head 30 ... Carriage 32 ... Operation panel 34 ... Sliding shaft 36 ... Drive belt 38 ... pulley 39 ... Position sensor 40 ... Control circuit 41 ... CPU 43 ... P-ROM 44 ... RAM 45 ... CG 50 ... I / F dedicated circuit 52 ... Head drive circuit 54 ... Motor drive circuit 56 ... Connector 60 ... Print head unit 90 ... Computer 91 ... Video driver 95 ... Application program 96 ... Printer driver 97 ... Resolution converter 98 ... Ink amount data conversion unit 99 ... Halftone processing unit 100 ... Print data generation unit 101 ... Brightness converter 102 ... Look-up table 103 ... Print mode selection section

Claims (29)

[Claims] 1. A printing apparatus for performing monotone printing of an image by ejecting ink onto a print medium, which is capable of ejecting black ink and a first chromatic color ink having a predetermined hue. Print head and a print mode selection unit that allows the user to select one monotone print mode from a plurality of monotone print modes having different color appearances, and the color of the monotone print mode selected by the print mode selection unit. A printing device comprising: an adjustment unit that adjusts the ejection amounts of the black ink and the first chromatic color ink so as to reproduce the feeling. 2. The printing device according to claim 1, wherein the black-based ink has a hue that is in a complementary color relationship with the first chromatic color ink. 3. The printing device according to claim 1, wherein the black-based ink is composed of a plurality of types of black-based ink having substantially the same hue and different densities. apparatus. 4. The printing apparatus according to claim 1, wherein the print head further includes at least one of at least one hue different from the hue of the first chromatic color ink. It is possible to eject two second chromatic color inks, and the adjustment unit is configured to, in each of the plurality of monotone print modes,
By ejecting the second chromatic color ink by an amount smaller than the ejection amount of the first chromatic color ink in the monotone printing mode in which the ejection amount of the first chromatic color ink is the largest, the color appearance of the printed image is improved. A printing device that makes fine adjustments. 5. The printing apparatus according to claim 4, wherein the adjustment unit is configured to set the plurality of monotone print modes in each of the plurality of monotone print modes.
A printing apparatus for finely adjusting the color appearance of a print image by ejecting the second chromatic color ink in an amount smaller than the ejection amount of the first chromatic color ink in the substantially achromatic monotone print mode. 6. The printing device according to claim 4, wherein the ejection amount of the second chromatic color ink does not depend on the monotone printing mode. 7. The printing device according to claim 4, wherein the second chromatic color ink has a lower density than the first chromatic color ink. 8. The printing device according to claim 4, wherein the print head includes a plurality of dark and light inks having substantially the same hue but different densities as the second chromatic color inks. The printing apparatus, wherein the adjustment unit uses ink having a relatively low density among the plurality of dark and light inks at the time of monotone printing. 9. The printing apparatus according to claim 1, wherein the adjustment unit uses the printing apparatus to print first image data represented by a first color system. An ink amount data conversion unit that performs conversion to second image data represented by a second color system composed of usable inks by using a lookup table; and a plurality of monotone printing modes. A plurality of look-up tables prepared correspondingly, wherein the ink amount data conversion unit selects and uses a look-up table corresponding to the selected monotone printing mode. 10. The printing apparatus according to claim 1, wherein the first chromatic color ink is yellow ink. 11. The printing apparatus according to claim 1, wherein the plurality of monotone print modes include a warm mode in which a hue of the entire image is biased toward yellow and a hue of the entire image. A printing device that includes a cool mode that is biased toward blue and a neutral mode that is nearly achromatic. 12. A printing method for performing monotone printing of an image by ejecting ink onto a printing medium, comprising:
(A) a step of preparing a print head capable of ejecting a black ink and a first chromatic color ink having a predetermined hue; and (b) a plurality of monotone printing modes having different color sensations. In order to reproduce the color appearance of the selected monotone print mode, the black ink and the first ink
A printing method comprising: a step of adjusting a discharge amount of chromatic color ink. 13. The printing method according to claim 12, wherein the black ink has a hue having a complementary color relationship with the first chromatic color ink. 14. The printing method according to claim 12, wherein the black ink is composed of a plurality of types of black ink having substantially the same hue and different densities. Method. 15. The printing method according to claim 12, wherein the print head further includes at least one of at least one hue different from the hue of the first chromatic color ink. It is possible to eject two second chromatic color inks, and in the step (b), in the monotone print mode in which the ejection amount of the first chromatic color ink is the largest in each of the plurality of monotone print modes. A printing method including a step of finely adjusting the color appearance of a print image by ejecting the second chromatic color ink in an amount smaller than the ejection amount of the first chromatic color ink. 16. The printing method according to claim 15, wherein the step (b) is performed in each of the plurality of monotone print modes.
Ejecting the second chromatic color ink by an amount smaller than the ejection amount of the first chromatic color ink in the almost achromatic color monotone printing mode, and performing a fine adjustment of the color appearance of the print image, Printing method. 17. The printing method according to claim 15, wherein the ejection amount of the second chromatic color ink does not depend on the monotone printing mode. 18. The printing method according to claim 15, wherein the second chromatic color ink is an ink having a density lower than that of the first chromatic color ink. 19. The printing method according to claim 15, wherein the print head uses, as the second chromatic ink, a plurality of dark and light inks having substantially the same hue but different densities. The step (b) is a printing method in which ink having a relatively low density among the plurality of dark and light inks is used in the monotone printing. 20. The printing method according to claim 12, wherein in the step (b), the printing is performed from the first image data represented by a first color system. A conversion step of performing conversion into second image data represented by a second color system composed of inks that can be used in the method using a lookup table; and corresponding to the plurality of monotone printing modes. And a step of preparing a plurality of look-up tables prepared by the above, wherein the converting step selects and uses a look-up table corresponding to the selected monotone printing mode. 21. The printing method according to claim 12, wherein the first chromatic color ink is yellow ink. 22. The printing method according to claim 12, wherein the plurality of monotone print modes include a warm mode in which the hue of the entire image is biased toward yellow and a hue of the entire image. A printing method that includes a cool mode in which is biased toward blue and a neutral mode that is almost achromatic. 23. A print head, which is capable of ejecting a black ink and a first chromatic color ink having a predetermined hue, is supplied to the printing unit for printing using the printing unit. A print control device for generating print data to be generated, wherein the print mode selection unit allows a user to select one monotone print mode from a plurality of monotone print modes having different color feelings, and the print mode selection unit An adjusting unit that adjusts the discharge amounts of the black ink and the first chromatic color ink so as to reproduce the color appearance of the selected monotone print mode, and according to the discharge amount of the ink adjusted by the adjusting unit, A print control device, comprising: a print data generation unit that generates print data indicating a discharge state of each ink in each pixel on a print medium. 24. The print control device according to claim 23, wherein the print head further includes at least one second chromatic color ink for at least one hue different from the hue of the first chromatic color ink. The adjustment unit may discharge the first chromatic color ink in the monotone print mode in which the discharge amount of the first chromatic ink is the largest in each of the plurality of monotone print modes. A finer adjustment of the color appearance of the print image by ejecting the second chromatic color ink in a smaller amount than the above. 25. The print control apparatus according to claim 23 or 24, wherein the adjustment unit is configured to perform the first existence in a substantially achromatic monotone print mode in each of the plurality of monotone print modes. A print control apparatus for finely adjusting the color appearance of a print image by ejecting the second chromatic color ink in an amount smaller than the amount of color ink ejected. 26. The print control device according to claim 23, wherein a discharge amount of the second chromatic color ink does not depend on the monotone print mode. Control device. 27. The print control device according to claim 23, wherein the adjustment unit uses the first image data represented by a first color system to determine the print device. An ink amount data conversion unit that performs conversion to second image data represented by a second color system that is composed of inks that can be used in a print table, and the plurality of monotone printing modes. And a plurality of lookup tables prepared corresponding to the above, wherein the ink amount data conversion unit selects and uses a lookup table corresponding to the selected monotone printing mode. 28. The print control device according to claim 23, wherein the plurality of monotone print modes include a warm mode in which the hue of the entire image is biased toward yellow, and a warm mode in which the hue of the entire image is biased. A print control device that includes a cool mode in which the hue is biased toward blue and a neutral mode that is nearly achromatic. 29. A computer program for generating print data to be supplied to a printing unit that performs monotone printing of an image by ejecting a black ink and a first chromatic ink having a predetermined hue onto a print medium. In addition, a function that allows the user to select one monotone print mode from a plurality of monotone print modes having different color sensations, and the black-based system to reproduce the color sensation of the selected monotone print mode. A function of adjusting the discharge amount of the ink and the first chromatic color ink, and a function of generating print data representing the discharge state of each ink in each pixel on the print medium according to the adjusted discharge amount of the ink. A computer program to be realized by a computer.