JP2002331693A - Single color printer and image processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To print a high quality monochrome image. SOLUTION: A black and white image is formed indistinctive of dots by preparing a plurality of achromatic color inks with different concentrations and at least one chromatic ink, and forming dots with the achromatic color inks on a printing medium based on image data. Moreover, the chromatic ink dots are formed among the achromatic color ink dots according to the image brightness. Thereby, a monochrome image with a high image quality can be realized with a hue indistinctive of dots. In the case where a plurality of chromatic inks are provided, by setting the ratio of the dot formation, a high quality monochrome image with a desired hue can be realized. By providing three kinds of inks, cyan, magenta, and yellow as the chromatic inks, a color image can be realized as well.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for displaying a high-quality monochromatic image.

[0002]

2. Description of the Related Art A color printer capable of displaying a color image by forming ink dots of each color ink on a print medium is widely used. In these color printers, various technologies have been developed to respond to the demand for higher image quality.
Today it is possible to print very high quality color images.

[0003] On the other hand, a monochrome image does not contain hue information, but has a higher density resolution than a color image, and in that sense, has a greater expressiveness.
The color printers are still used today even when the image quality has been improved. In addition, since a monochrome image can represent an image having a unique atmosphere by associating an old photograph, a color image is intentionally converted to a monochrome image and printed. .

[0004]

However, as described above, the image quality of color printers has been improved, and the image quality obtained by a conventional single-color printer is relatively lower than that of a print image obtained by a color printer. Was inferior to others.

The present invention has been made to solve the above-mentioned problems in the prior art, and has as its object to provide a technique capable of expressing a higher quality monochrome image.

[0006]

Means for Solving the Problems and Their Functions and Effects In order to solve at least part of the above-mentioned problems, the printing apparatus of the present invention employs the following configuration. That is, in a printing apparatus that prints a single-color image by providing a plurality of achromatic inks having different densities and forming various dots of the achromatic ink on a print medium based on image data, at least one chromatic ink is provided. And mixing the chromatic ink dots with the achromatic ink dots,
A chromatic color dot forming means for forming a chromatic color dot at a predetermined density in accordance with brightness information included in the image data.

In such a printing apparatus, when a plurality of types of achromatic ink dots having different densities are formed to print a monochromatic image, the dots are mixed with the achromatic ink dots.
The chromatic ink dots are formed at a predetermined density according to the brightness of the image. If the dots of the achromatic ink and the dots of the chromatic ink are formed in this manner, the hue is given according to the brightness of the image, and a high-quality monochromatic image can be expressed accordingly.

In such a printing apparatus, a first chromatic color ink and a second chromatic color ink having different hues are provided in advance, and the dot density of the first chromatic color ink and the second chromatic color ink are determined. The dots of the first chromatic ink and the dots of the second chromatic ink may be formed such that the ratio of the density of the chromatic ink to the density of the dots becomes substantially constant.

If the dots of the first chromatic color ink and the dots of the second chromatic color ink are formed at a substantially constant ratio to each other, the hue can be uniformly applied to the monochromatic image. It is suitable.

[0010] In the present specification, a monochromatic image means an image having a single hue, and is not limited to an image formed with a single ink. For example, even if an image is obtained by forming dots of a plurality of types of ink at substantially the same ratio, if the image presents a single hue as a result, it corresponds to the monochromatic image in the present specification. I do.

The first chromatic ink and the second chromatic ink may include magenta ink and yellow ink. This is preferable because a so-called sepia tone or warm tone monochrome image can be printed.

Similarly, the first chromatic color ink and the second chromatic color ink may include magenta ink and cyan ink. This is preferable because a so-called cool monochrome image can be printed.

In the above-described printing apparatus of the present invention, the chromatic inks may include cyan ink, magenta ink, and yellow ink.

It is preferable to form dots of these inks at an appropriate ratio in addition to the dots of the achromatic ink, since it becomes possible to impart various hues to a monochrome image. Further, in such a printing apparatus, it is preferable to form a mixture of dots of various inks of cyan, magenta, and yellow so that a color image can be printed.

In a printing apparatus capable of forming dots using a plurality of chromatic inks, the achromatic dot forming means for forming dots using achromatic ink and the chromatic dot forming means may be configured as follows. First, a dot forming section for forming dots on a print medium is provided for each type of ink. These dot forming units form dots when a drive signal is received in a state where power for forming dots is supplied. The power is supplied to each of the dot forming units provided in the achromatic color dot forming unit and the chromatic color dot forming unit, and the power is supplied to at least each of the dot forming units provided in the chromatic color dot forming unit. It is good also as supplying with.

In the case where the achromatic color dot forming means and the chromatic color dot forming means form dots using electric power, if the power supplied to each dot forming section varies, the dot forming ability is reduced by each ink. It will be different every time.
Since the dots of chromatic ink express the hue by the dot formation ratio between the inks, it is difficult to accurately reproduce the hue if the dot forming ability varies for each chromatic ink. Therefore, the image quality may be deteriorated. Therefore, if power is supplied to at least the dot forming unit provided in the chromatic color dot forming means by the same system, it is possible to prevent the supplied power from varying between these chromatic color dots. This is because, even if the supply power changes, all the dot forming portions for the chromatic color change at the same time, and there is no variation between the chromatic dots. As a result, a stable hue can be always expressed, and a high-quality image can be printed.

Of course, when power is supplied to the dot forming section for chromatic ink and the dot forming section for achromatic ink in different systems, the ratio of achromatic color dots to chromatic color dots varies. Become. Similarly, when power is supplied between the achromatic ink dot forming units by another system, the dot formation ratio between the achromatic dots varies. However, even if the formation ratio of the achromatic dots fluctuates in this manner, only the brightness of the image fluctuates, and the effect on the image quality is not so large as the fluctuating ratio of the dots between the chromatic dots fluctuates. .
From this, for example, power is supplied to the first chromatic color ink dot forming unit and the second chromatic color ink dot forming unit in the same system, and the achromatic color ink dot forming unit is supplied with:
Electric power may be supplied by another system. Or,
Power may be supplied to the dot forming units for cyan ink, magenta ink, and yellow ink in the same system, and power may be supplied to the dot forming units for achromatic ink in another system. This makes it possible to print an image with stable image quality.

In the above-described printing apparatus, three types of achromatic inks having different densities may be provided as a plurality of achromatic inks. Furthermore, cyan ink,
In addition to the magenta ink and the yellow ink, three types of achromatic inks having different densities may be provided.

By forming dots of these plural types of achromatic inks, it is possible to form an image with inconspicuous dots. In addition to these achromatic ink dots, cyan ink, magenta ink and yellow ink can be formed. Forming the dots appropriately is preferable because a high-quality monochrome image with a desired hue can be printed.

Of course, if the cyan ink dots, the magenta ink dots, and the yellow ink dots are mixed in approximately equal amounts, it is possible to express a monochrome image. However, these dots are mixed. A so-called light source dependence problem that an unintended hue appears in the image depending on the type of the light source may occur in the monochrome image. Also, if there is a portion where the density of each dot of cyan, magenta and yellow is shifted, a problem called so-called color twist may occur, in which an unintended hue appears in a monochrome image at that portion. On the other hand, in the above-described printing apparatus, since a monochrome image is expressed using a plurality of dots of achromatic ink, there is no problem of light source dependence and color twist,
Thus, it is possible to express a high-quality monochrome image.

If three types of achromatic inks are provided, the three types of chromatic color inks of cyan, magenta and yellow inks can be used.
A total of six types of ink will be provided. Assuming that the total number of ink types is six, a so-called six-color printer, that is, a total of six types of cyan ink, magenta ink, yellow ink, black ink, low-density cyan ink, and low-density magenta ink It is preferable that a high-quality monochrome image can be easily realized by changing the ink in a color printer having the ink.

In the printing apparatus of the present invention described above, the plurality of achromatic inks may include the same number of chromatic inks or more inks than the chromatic inks.

If a variety of inks are provided and dots of these inks are appropriately formed, it is possible to print a high-quality image. However, as the number of types of ink increases, the space for accommodating the ink is required. Or the size of the printing apparatus is increased, so that the type of ink is naturally limited. Under such restrictions on the kind of ink, if the number of achromatic inks is the same as the number of chromatic inks, or is more than the number of chromatic inks, image quality can be improved efficiently. It is preferable because it becomes possible.

Further, in the above-described printing apparatus, dots are formed by receiving the supply of ink. When the supplied ink changes, the dots formed on the print medium also differ. Therefore, the present invention can be understood as an ink container that stores the supply ink in the printing apparatus as follows. As described above, the present invention grasped as an ink container is mounted on a printing device that receives supply of image data and ink and prints an image corresponding to the image data, and stores the ink to be supplied to the printing device. In the ink container, the printing apparatus is an achromatic dot forming means for forming a plurality of dots of achromatic ink having different densities, and a mixture of dots of chromatic ink and dots of the achromatic ink, A chromatic dot forming unit that forms at a predetermined density according to the brightness information included in the image data, wherein the plurality of achromatic inks and the chromatic ink used in the printing apparatus are The gist of the present invention is to provide an ink storage unit for storing separately.

Further, the printing apparatus is provided with three printing apparatuses having different densities.
In the case of a printing apparatus that receives supply of three types of achromatic inks and three types of chromatic inks of cyan ink, magenta ink, and yellow ink and forms dots with the respective inks, the ink included in the ink container is provided. The accommodation section may be as follows. That is, a storage unit that separately stores the three types of achromatic ink, the cyan ink, the magenta ink, and the yellow ink may be used.

When such an ink container is mounted on a printing apparatus, the printing apparatus can form high-quality monochrome images by forming dots of achromatic ink and dots of chromatic ink.

Alternatively, the present invention can be understood as the following ink container. That is, an ink container that is mounted on a printing device that receives supply of image data and ink and prints an image corresponding to the image data and stores ink to be supplied to the printing device, wherein the printing device has a density of Achromatic dot forming means for forming dots with a plurality of different achromatic inks, and dots of chromatic ink, mixed with the dots of the achromatic ink,
A chromatic dot forming unit that forms at a predetermined density according to the brightness information included in the image data, wherein the ink container includes the plurality of achromatic inks used in the printing device. An ink storage unit for separately storing ink is provided, and the gist is that the ink having the lowest density among the plurality of achromatic inks can store a larger amount of ink than the other achromatic inks.

As described above, in a printing apparatus for printing an image by forming dots using a plurality of achromatic inks having different densities, the achromatic ink having the lowest density tends to be used in a larger amount than other inks. There is. Therefore, if the ink containing portion of the ink containing body can store the least concentrated achromatic ink in a larger amount than the other achromatic inks, the achromatic ink alone is not used up quickly. preferable.

In order to solve at least a part of the problems of the prior art, the image processing apparatus of the present invention employs the following configuration. That is, in an image processing apparatus that converts image data into an expression format based on the presence / absence of a plurality of types of dots, an achromatic color dot for determining the presence / absence of a plurality of types of achromatic dots having different densities based on the image data. Forming determination means, and chromatic color dot generation means for generating at least one type of chromatic color dots at a predetermined density in accordance with the information on the brightness included in the image data by mixing the chromatic color dots with any one of the achromatic color dots. It is characterized by having.

The image processing method of the present invention corresponding to the image processing apparatus described above is a method of converting image data into an expression format based on the presence or absence of a plurality of types of dots. Determining whether or not chromatic dots are formed based on the image data; and mixing at least one type of chromatic dots with any of the achromatic dots to obtain lightness information included in the image data. Generating at a predetermined density according to the density.

In the image processing apparatus and the image processing method, the image data is converted into an expression format based on the presence or absence of dot formation for a plurality of types of achromatic dots having different densities, and the image data is stored at a predetermined density according to the brightness of the image. Generate colored dots.

It is preferable to form various dots on a medium based on the image data converted in this way, since a high-quality monochrome image with a desired hue can be expressed.

In such an image processing apparatus, the first chromatic color dots and the second chromatic color dots having different hues may be generated so that the density ratio between them is substantially constant. It is preferable to form various dots on a medium based on the image data obtained in this way, since a monochrome image with uniform colors can be expressed.

In this image processing apparatus, the first
And a density ratio between the density of the chromatic color dot and the density of the second chromatic color dot can be set, and the first chromatic color dot and the second chromatic color dot can be set at the set density ratio. It may be generated by.

It is preferable to form various dots based on the image data obtained in this way, since it is possible to change the color given to the monochrome image by setting the density ratio.

Similarly, in such an image processing apparatus,
The predetermined density for generating the chromatic color dots may be set according to the brightness of an image. It is preferable to form various dots based on the image data obtained in this way, because the setting of the predetermined density makes it possible to change the degree of imparting color to a monochrome image.

In the above-described image processing apparatus of the present invention, the respective densities of cyan dot, magenta dot and yellow dot can be set to each other, and the cyan dot, the magenta dot and the magenta dot can be set at the set ratio. The dots and the yellow dots may be generated.

The cyan dot, the magenta dot, and the yellow dot can represent various colors by being combined with each other. Therefore, if various dots are formed on a medium based on the image data thus obtained, it is possible to obtain desired colors. It is preferable because it is possible to express a high-quality monochrome image to which the hue is given.

Further, the image processing method of the present invention can be implemented by using a computer by incorporating a program for realizing a predetermined function into the computer. Therefore, the present invention also includes the following aspects. That is,
A recording medium corresponding to the image processing method of the present invention is a computer-readable recording medium that records a program for converting image data into an expression format based on the presence or absence of a plurality of types of dots. A function of determining whether or not to form a dot based on the image data, and at least one type of chromatic dot,
A function of generating the image data at a predetermined density in accordance with the brightness information included in the image data by mixing with any one of the achromatic dots.

Similarly, a program corresponding to the image processing method of the present invention is a program for converting image data into an expression form based on the presence or absence of the formation of a plurality of types of dots. A function of determining the presence / absence based on the image data; and mixing at least one type of chromatic dot with any of the achromatic dots at a predetermined density according to the brightness information included in the image data. The function to generate and the program to realize.

By reading these programs into a computer and forming various dots based on the obtained image data, a high-quality monochrome image can be expressed.

[0042]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to more clearly explain the operation and effects of the present invention, embodiments of the present invention will be described below in the following order. A. First embodiment: A-1. Device configuration: A-2. Image processing: A-3. Modifications: B. Second embodiment: B-1. Device configuration: B-2. Image processing:

A. First embodiment: A-1. Apparatus Configuration: FIG. 1 is an explanatory diagram showing the configuration of a printing system including a printing apparatus and an image processing apparatus according to the present invention. As shown in the figure, the printing system has a configuration in which a printer 20 is connected to a computer 80. When a predetermined program is loaded and executed on the computer 80, the computer 80 and the printer 20 are connected.
Function as an integrated printing system as a whole. As an image to be printed, an image created by various application programs 91 on the computer 80 is used. It is also possible to use an image captured by using the scanner 21 connected to the computer 80 or an image captured by a digital camera (DSC) 28 via the memory card 27 and used.
The data ORG of these images is converted into image data that can be printed by the printer 20 by the CPU 81 in the computer 80, and is converted as print data FNL into the printer 20.
Is output to The printer 20 transmits the print data FNL
When the formation of the ink dots on the printing paper is controlled according to the above, an image is finally printed on the printing paper.

The computer 80 includes a CPU 81 for executing various arithmetic processing and a RAM for temporarily storing data.
83, a ROM 82 for storing various programs, a hard disk 26 and the like. Also, SIO
By connecting 88 to the public telephone line PNT via the modem 24, it becomes possible to download necessary data and programs from the server SV on the external network to the hard disk 26.

The printer 20 is a printer that includes a plurality of achromatic inks having different densities and forms high-quality monochrome images on printing paper by forming dots of these achromatic inks. The printer 20 of this embodiment includes at least one chromatic color ink in addition to the achromatic ink. As described later, by forming the chromatic color ink dots in addition to the achromatic color ink dots, High-quality monochrome images can be printed.

The printer 20 employs a method of forming ink dots on printing paper by discharging ink using piezo elements. Although the printer 20 used in the present embodiment employs a method of ejecting ink using piezo elements, a printer having a nozzle unit for ejecting 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. Further, a printer of a type that forms ink dots on printing paper by using a phenomenon such as thermal transfer instead of discharging ink may be used.

FIG. 2 is a block diagram conceptually showing a software configuration of a computer 80 for realizing the functions of the image processing apparatus of the present embodiment. Computer 80
, All application programs 91
Runs under the operating system. A video driver 90 and a printer driver 92 are incorporated in the operating system. Image data output from each application program 91 is converted into a predetermined signal by the video driver 90, and then converted to a monitor 23.
Is displayed with.

When the application program 91 issues a print command, the printer driver 92 of the computer 80 receives image data from the application program 91, performs predetermined image processing, and converts the image data into print data FNL that can be printed by the printer. Thereafter, the converted print data FNL is output to the printer 20. The details of the image processing will be described later.

FIG. 3 is an explanatory diagram showing a schematic configuration of the printer 20 of this embodiment. As shown in the figure, the printer 20 drives a print head 41 mounted on a carriage 40 to eject ink and form dots.
The carriage 40 includes a mechanism for reciprocating the carriage 40 in the axial direction of the platen 36 by the carriage motor 30, a mechanism for conveying the printing paper P by the paper feed motor 35, and a control circuit 60.

The mechanism for reciprocating the carriage 40 in the axial direction of the platen 36 includes a sliding shaft 33 that slidably holds the carriage 40 erected in parallel with the axis of the platen 36.
Between the endless drive belt 3 and the carriage motor 30
1 and a position detection sensor 34 for detecting the origin position of the carriage 40.

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. Printing paper P
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.

The control circuit 60 includes a CPU 61 and a ROM 62
And a RAM 63 for controlling various mechanisms of the printer 20. That is, the control circuit 60 controls the main scanning and the sub-scanning of the carriage 40 by controlling the operations of the carriage motor 30 and the paper feed motor 35, and also controls each of the carriages 40 based on the image data FNL supplied from the computer 80. The ejection of ink droplets from the nozzles is controlled. As a result, ink dots are formed at appropriate positions on the printing paper.

The carriage 40 is provided with an ink cartridge 42 for mounting a plurality of achromatic inks and an ink cartridge 43 for mounting chromatic inks.
The ink cartridge 42 loaded with achromatic ink includes:
A total of three types of achromatic inks are mounted: a black ink, a gray ink having a higher brightness than the black ink, and a light gray ink having a higher brightness than the gray ink. Magenta ink and yellow ink are mounted on the ink cartridge 43 on which chromatic ink is mounted. Of course, the combination for mounting various inks is not limited to this, and all these inks may be stored in one cartridge. In the following, the black ink, the gray ink, the light gray ink, the magenta ink, and the yellow ink will be referred to as K1 ink, K2 ink, respectively.
The ink, K3 ink, M ink, and Y ink are abbreviated.

FIG. 4 is an explanatory view illustrating various aspects of the ink cartridge. FIG. 4A shows an aspect of the ink cartridge mounted on the printer 20 of the present embodiment. As shown in the figure, the ink cartridge 42 contains three types of achromatic inks of K1 ink, K2 ink, and K3 ink.
Contains two types of chromatic inks of Y ink and M ink. Here, the ink cartridge 42
Can store more K3 ink, which is the thinnest ink among achromatic inks, than other inks. This will be described in detail later, but since the K3 ink tends to consume more ink than other achromatic inks,
The K3 ink capacity is set larger than other inks so that only three inks are not used up quickly. In FIG. 4A, the ink storage amounts of the Y ink and the M ink are substantially the same, but since the Y ink tends to consume a larger amount of ink than the M ink, The ink may be stored more than the M ink.

The printer 20 includes the ink cartridge 4
Although two cartridges 2 and 43 are mounted, these cartridges can be integrated into one cartridge. FIG. 4B illustrates such an integrated ink cartridge.
In the ink cartridge shown in FIG. 4B, the ink storage capacity of the Y ink in addition to the K3 ink is larger than that of the other inks. Further, as will be described later, when the printer can form dots of each color ink of C, M, and Y as dots of chromatic color ink, as shown in FIG. 4C, C, M, Y, K1, It is also possible to provide an ink cartridge in which K2 and K3 color inks are integrally accommodated.
Alternatively, as shown in FIG. 4D, one ink (for example, K1 ink) is housed in a single cartridge, and another achromatic ink (for example, K2, K3 ink) and a chromatic ink (C, M, Y) are stored. (Ink) may be housed in an integral cartridge. Even in such a case, it is desirable to maximize the capacity of the K3 ink. of course,
It is also possible to use the K3 ink having the largest capacity as a single cartridge. Thus, if a plurality of inks can be stored in one cartridge, the ink cartridge can be made compact. Further, each ink may be stored in a single ink cartridge. This has the advantage that each ink can be replaced independently.

The ink cartridge 4 is mounted on the carriage 40.
When the cartridges 2 and 43 are mounted, the respective inks in the cartridge are supplied to the ink discharge heads 44 to 48 for each color through an introduction pipe (not shown). The ink supplied to each head is ejected from the ink ejection heads 44 to 48 under the control of the control circuit 60.

FIG. 5 shows the ink ejection heads 44 to 4.
FIG. 8 is an explanatory diagram showing an arrangement of inkjet nozzles Nz in FIG. As shown in the figure, on the bottom surface of the ink discharge head, five sets of nozzle rows for discharging inks of K1, K2, K3, M, and Y are formed, and 48 nozzle rows are provided for each set of nozzle rows. The nozzles Nz are arranged at a constant nozzle pitch k.

As described above, in the printer 20, the ink droplets are ejected by driving the piezo elements, and the power for driving is supplied by two systems. That is, two systems are provided: a system for supplying power to the ink ejection heads of K1, K2, and K3 inks, and a system for supplying power to the M ink and the Y ink. When the power supplied to the ink ejection head varies,
Since the ink ejection amount fluctuates, image quality may be deteriorated. In particular, when a plurality of chromatic inks are ejected, if the amount of power supply varies, the amount of ink ejected between the chromatic inks changes, so that the hue changes and the image quality may be degraded. The power to the ink ejection head is supplied from a power supply circuit, and the power supply amount to each head may vary due to the influence of manufacturing variations of the circuit. Therefore, if power is supplied from one system to the chromatic ink discharge head, even if the supply power fluctuates, the discharge amount of the chromatic ink fluctuates simultaneously. Therefore, it is possible to prevent the image quality from being deteriorated due to the change in the hue. Of course, for the achromatic ink, if the power is supplied from the same system, even if the supply amount of the power varies, the discharge amount does not fluctuate between these achromatic inks, so that the deterioration of the image quality is suppressed. be able to.

The printer 20 having the above-described hardware configuration drives the carriage motor 30 to move the ink discharge heads 44 to 48 of each color in the main scanning direction with respect to the printing paper P. By driving the feed motor 35, the printing paper P is moved in the sub-scanning direction. Under the control of the control circuit 60, the printer 20 prints a monochrome image on printing paper by driving the nozzles and discharging ink droplets at appropriate timing while repeating the main scanning and sub-scanning of the carriage 40. I have.

A-2. Image Processing: FIG. 6 is a flowchart showing the flow of processing in which a computer 80 as an image processing apparatus of the present embodiment converts image data into print data by performing predetermined image processing. This process is started when the operating system of the computer 80 activates the printer driver 92. Hereinafter, the image processing of this embodiment will be briefly described with reference to FIG.

When the image processing routine is started, the printer driver 92 first starts reading image data to be converted (step S100). The printer 20 according to the present embodiment is a printer that prints a monochrome image, and the image data can be either color image data or monochrome image data. Here, the description will be made assuming that RGB color image data is read.

Next, the resolution of the fetched image data is converted into a resolution for printing by the printer 20 (step S102). When the resolution of the image data is lower than the print resolution, new data is generated between adjacent image data by performing linear interpolation.On the other hand, when the resolution is higher than the print resolution, the data is thinned out at a fixed rate. The resolution of the image data is converted to the print resolution.

After the resolution has been converted in this way, the brightness conversion processing is started (step S104). In the brightness conversion process, the image data is once converted into brightness data representing the brightness of the image, and the obtained brightness data is then converted to K1, K2, K3.
Is converted to dot density data representing the dot formation density for each achromatic ink. Hereinafter, description will be made in order.

The RGB color image data read in step S100 includes color information and lightness information dispersedly in tone data of each of R, G, and B colors. Therefore, first, brightness information included in the gradation data of each color is extracted, and the image data is converted into brightness data representing the brightness of the image. Specifically, R,
Brightness data can be obtained by adding the gradation values of the G and B color data. The brightness data thus obtained indicates that the larger the value, the higher the brightness (bright) of the image, and the smaller the value, the lower the brightness (dark) of the image. Of course, other known methods can be applied to the extraction of the brightness information. For example, the brightness data can be obtained by adding different weights to the tone values of the R, G, and B color data for each color. May be required. In step S100, if image data of which brightness is separated, such as black-and-white image data or color image data expressed in Lab format, is read, the process of converting to brightness data is omitted. Can be.

The brightness data thus obtained is converted into dot density data for each of the achromatic inks K1 (black), K2 (gray), and K3 (light gray). The dot density data is an index relating to the density at which dots are formed per unit area. Such conversion can be easily performed by referring to a conversion table called a dot density table. FIG. 7 is an explanatory diagram showing how the brightness data is converted into dot density data for each achromatic ink with reference to the dot density table.

As shown in the figure, in the dot density table, dot density data for each of the achromatic inks K1, K2, and K3 is set for the brightness data.
By referring to such a table, the brightness data can be converted to dot density data. For example, assuming that the tone value of the brightness data is "A", the brightness data is represented by K1 by referring to the dot density data.
The dot density data of the ink is converted to DA1, and the dot density data of the K2 ink is converted to DA2. Note that the tone value “0” of the dot density data indicates that no dots are formed on the printing paper, and the tone value “255” of the dot density data indicates a so-called solid state, that is, the printing paper. This indicates that dots are uniformly formed on the top.
As for the brightness data, as described above, the tone value “255” of the brightness data indicates the brightest image, that is, the image of the background color of the printing paper, and the tone value “0” of the brightness data. Indicates the darkest image, that is, a black image.

As shown in FIG. 7, the dots of the K1 ink are formed only in the area where the tone value of the brightness data is near "0", and the dots of the K2 ink are the dots of the brightness data. It is formed only in the region where the tonal value is from "0" to the intermediate gradation. On the other hand, the dots of the K3 ink are formed in a wide area from low gradation to gradation value “255”. Thus, the dots of the K3 ink are the dots that are formed most frequently. With this in mind,
The ink cartridge mounted on the printer 20 is set so that the storage amount of K3 ink, which is considered to be the largest ink consumption, is larger than other inks (see FIG. 4).

When the brightness conversion processing is completed as described above, subsequently, the color tone provision processing is started (step S10).
6). The color tone imparting process is a process of imparting a preset color tone to a monochrome image. That is, the printer 20 of the present embodiment can print not only achromatic monochrome images but also chromatic monochrome images such as sepia tone and warm tone. The kind of color and the degree to which the monochrome image is given are set in advance before printing. In the color tone imparting process, a process of generating dot density data for chromatic ink dots is performed based on the setting. As a preparation for describing the color tone imparting process, first, a process of setting a color to be imparted to a monochrome image will be described.

The color given to the monochrome image is set in the printer driver 92 in advance. FIG. 8 is an explanatory diagram showing a state in which colors to be given are set in advance for the printer driver 92 from the monitor 23 of the computer 80. As shown in the figure, when the color tone setting screen of the printer driver 92 is opened, a box for setting the color tone to be applied to the monochrome image is displayed at the top of the screen, and a box for setting the amount of color tone to be applied is displayed at the bottom of the screen. Is displayed.

First, the process of setting the color tone using the box at the top of the screen will be described. As described above, the printer 20 of the present embodiment converts an arbitrary color tone from magenta to yellow into a monochrome image in correspondence with the provision of the M ink and the Y ink as chromatic inks. Can be granted. For example, if the arrow displayed in the box is set to the position where "magenta" is displayed, the monochrome image is given a magenta color tone. If the arrow in the box is set near the position where "sepia tone" is displayed, a sepia tone according to the position of the arrow can be given to the monochrome image.

In the box at the bottom of the screen, the amount of color tone set in the box at the top of the screen is set. The desired amount of color tone can be set by moving the arrow in the box. For example, if the position of the arrow is set to the position where "not applied" is displayed, it means that a black-and-white image with no color tone has been set. As the position of the arrow is gradually moved to the right side, the monochrome image gradually changes from a black-and-white image to a color-tone image. By setting the arrow at an appropriate position in this way, it is possible to set the amount of color tone to be applied to the monochrome image to a desired value.

The tone imparting process shown in FIG. 6 (step S1)
In step 06), dot density data of M dots and dot density data of Y dots are generated based on the setting of the color tone.

FIG. 9 is an explanatory view exemplifying a state in which dot density data of M dots and dot density data of Y dots are generated in accordance with the brightness data of an image. As shown, when the tone value of the brightness data is “255”, the dot density data of either the M dot or the Y dot takes the tone value “0”, and increases linearly as the brightness data decreases. Therefore, when the tone value of the brightness data is “0”, the brightness data has the maximum value.

The ratio between the dot density data of M dots and the dot density data of Y dots is kept constant irrespective of the value of the brightness data, and the value of this ratio is determined as described above with reference to FIG. It depends on the color tone set in the printer driver 92 in advance. That is, in the setting example of FIG. 8, a setting is made so as to give a “sepia tone” color tone to a monochrome image, and accordingly, in the example shown in FIG. Is larger than the dot density data of. Also, in the case where the setting is made so as to give the “warm” color tone in FIG. 8, the dot density data of the Y dot and the dot density data of the M dot are
The values are almost the same.

The setting of the amount of color tone described with reference to FIG.
The absolute value of the value “0” of the brightness data is determined for the dot density data having the larger value among the dot density data of the dots or Y dots. For example, in the setting example of FIG. 8, the arrow for setting the tone application amount is set substantially at the center, and in response to this, in the example shown in FIG. 9, the dot density data having the larger value is set. (In this case, the dot density data of the Y dot) has a tone value of about “128” at the position of the brightness data “0”.
If the position of the arrow for setting the color tone application amount is at the position indicated as “large” as shown by the thin broken line in FIG. 8, the dot density data of the Y dot is shown in FIG. The value is set as shown by a thin broken line. The dot density data of the M dots is set so as to maintain a predetermined ratio with respect to the dot density data of the Y dots thus set.

In the color tone provision processing shown in step S106 of FIG. 6, the dot density data of the M dots and the dot density of the Y dots are determined in accordance with the preset color tone and the amount of the color tone. And generate data.
In FIG. 9, the dot density data of the M dot and the Y dot are described as being set to increase linearly as the brightness data decreases. However, it is not always necessary to increase the dot density data linearly. Alternatively, the dot density data of the M dots and the Y dots may be increased in a curved manner while keeping the ratio of each other constant so that a more preferable monochrome image is obtained.

When the tone application process is completed, the tone number conversion process is started (step S108).
The gradation number conversion processing is the following processing. As described above, the dot density data is represented by 256 gradation values from 0 to 255.
Although the data has a gradation, in reality, only a state of “forming” or “not forming” a dot on printing paper can be taken. Therefore, it is necessary to convert dot density data having 256 gradations into data of two gradations corresponding to the presence or absence of dots. As described above, the tone number conversion process is a process of converting the dot density data of 256 tones into image data indicating whether or not dots are formed. Although various methods are known as a method of performing the gradation number conversion process, in the present embodiment, the gradation number conversion process is performed using a method called an error diffusion method. Of course, other well-known methods may be used.

Following the tone number conversion process, an interlace process is performed (step S110). The interlacing process is a process of rearranging the image data converted into a format representing the presence or absence of dot formation into an order in which the image data should be transferred to the printer 20 in consideration of the order in which the printer actually forms dots. The printer driver outputs the image data finally obtained by performing the interlacing process to the printer 20 as print data (step S112). The printer 20 forms various ink dots on print paper according to the print data. As a result, a monochrome image corresponding to the image data is printed on the printing paper.

As described above, the printing system of this embodiment forms sepia tone and warm tone by forming dots of M ink and Y ink at a predetermined ratio in addition to dots of achromatic ink. First, a monochrome image having a desired color tone can be printed. Of course, since the printer 20 has three achromatic inks of K1 ink, K2 ink, and K3 ink having different densities, by forming dots of these inks, high-quality images with inconspicuous dots are formed. Black and white image can be printed. The printing system of the present embodiment can print a higher quality monochrome image by giving a desired color tone to such a high quality black and white image.

A-3. Modifications: The printer 20 of the first embodiment has been described as being provided with the M ink and the Y ink as the chromatic inks. However, the present invention is not limited to this. Combining C ink and M ink, or C ink, M ink
A single chromatic ink, such as ink or Y ink, may be provided. Further, so-called special color ink such as green ink or sepia ink may be provided as chromatic color ink.

Also, a plurality of inks having different densities may be provided for the chromatic color inks, and dots may be formed using low-density inks in areas where the brightness of the image is high (bright). In this way, for example, in a region where chromatic ink dots are easily conspicuous, by forming dots using low-density ink, it is possible to avoid that chromatic ink dots are conspicuous and deteriorate image quality. , And a higher quality monochrome image can be printed.

B. Second Embodiment: Printer 2 of First Embodiment
0, three types of achromatic inks K1, K2, and K3;
Although two chromatic inks of the M ink and the Y ink are provided, the printer 120 according to the second embodiment has a portion including three inks of the C ink, the M ink, and the Y ink as the chromatic inks. Are very different. Hereinafter, the printer 120 according to the second embodiment will be described.

B-1. Apparatus configuration: The printer 120 of the second embodiment includes three achromatic inks of K1 ink, K2 ink, and K3 ink and three achromatic inks of C ink, M ink, and Y ink.
And two chromatic inks. The achromatic ink is stored in the ink cartridge 42 and the chromatic ink is stored in the ink cartridge 43. Further, the ink discharge head has a configuration in which a C color ink discharge head 49 is added to the K1, K2, K3, M, and Y ink discharge heads 44 to 48.

FIG. 10 is an explanatory diagram showing the nozzle arrangement of the printer 120 according to the second embodiment. As shown in the drawing, K1, K2, K3, M,
Six sets of nozzle rows for ejecting ink of each color of Y and C are formed, and 48 nozzles Nz are provided for each set of nozzle rows.
Are arranged at a constant nozzle pitch k.

B-2. Image processing: As described above, the second
In the printer 120 of the embodiment, C ink is added as a new chromatic ink to the printer 20 of the first embodiment described above. To that extent, the color tone to be applied can be selected from a wider range, and a high-quality monochrome image can be printed. Further, since the printer 120 of the second embodiment is provided with the inks of the respective colors of C, M, and Y, by forming the dots of these chromatic color inks at an appropriate density, the normal It can also be used as a color printer. Hereinafter, image processing in the printing system of the second embodiment will be described.

FIG. 11 is a flowchart showing the flow of the image processing of the second embodiment. The image processing of the second embodiment is as follows.
The portions that can be used for printing a color image are greatly different from the image processing of the first embodiment described above, and the details of the processing will be described focusing on such portions.

Also in the second embodiment, when the image processing routine is started, first, image data to be converted is read (step S200), and then the resolution of the read image data is printed by the printer 120. The resolution is converted (step S202).

After the resolution has been converted, it is determined whether the image to be printed is a monochrome image (step S204). Whether the image is printed as a monochrome image or a color image is set in the printer driver in advance, and in step S204, a determination is made based on the setting. If it is set to print a monochrome image (step S204: yes), the brightness conversion process (step S2) is performed as in the first embodiment described above.
06) and color tone provision processing (step S208). When printing a monochrome image, the color tone to be given to the monochrome image is set in advance in the printing system of the second embodiment as in the case of the first embodiment. Since the printing system of the second embodiment uses three types of chromatic inks of C, M, and Y, the degree of freedom in setting the color tone is increased by that much compared to the printing system of the first embodiment. The color tone to be given to the monochrome image is set as follows.

FIG. 12 is an explanatory diagram showing a state in which a color tone to be given to a monochrome image is set in the printing system of the second embodiment. Also in the second embodiment, when the color tone setting screen of the printer driver 92 is opened,
A box for setting a color tone to be applied to the monochrome image is displayed, and a box for setting an amount of color tone to be applied is displayed at a lower portion of the screen. Since only the box at the top of the screen is different from the screen of the first embodiment, the setting using such a box will be described below.

As described above with reference to FIG. 8, in the color tone setting screen of the first embodiment, the arrow for setting the color tone is placed at an appropriate position between “magenta” and “yellow”. The color tone to be added to the monochrome image was set. On the other hand, in the second embodiment, the position of the arrow can be set to any position between “cyan”, “magenta”, and “yellow”. In the example shown in FIG. 12, since the arrow is provided at a position between "cyan" and "cyan" between "cyan" and "magenta", the color tone given to the monochrome image is slightly magenta-cyan. This means that the color tone has been set. As shown in FIG. 12, such a color tone given to a monochrome image is usually called a cool tone.

In the color tone provision processing (step S208 in FIG. 11) in the image processing routine of the second embodiment, FIG.
The dot density data of C dots, M dots, and Y dots is generated in accordance with the color tone set using the screen shown in FIG. The process of generating dot density data is the same as the process of the first embodiment described above except for the portion where C dots are added, and a description thereof will be omitted.

On the other hand, if it is determined in step S204 of FIG. 11 that the image to be printed is not a monochrome image (step S204: no), a color conversion process is performed (step S210). The color conversion process is to convert the RGB image data read in step S200 into C,
This is a process of converting into tone data of each color of ink provided in the printer such as M and Y. In the LUT referred to in the color conversion processing of the present embodiment, the colors represented by the combinations of the gradation values of the R, G, and B colors are represented by C, M, Y, K1, K2,
The dot density data for each color ink to be expressed using each color of K3 is stored. In the processing of step S204 in FIG. 11, the RGB image data is converted into C, M, Y, K1, K2, and K by referring to the LUT.
3 can be quickly converted to dot density data for each color.

As described above, the color tone provision processing (step S208) or the color conversion processing (step S210)
Is completed, the tone number conversion process (step S212) and the interlace process (step S214) are performed, and the obtained data is used as print data in the printer 120.
(Step S216). The gradation number conversion processing and the interlace processing are the same as in the first embodiment described above, and the description is omitted here. The printer 120 can print either a monochrome image or a color image by forming ink dots of each color in accordance with the print data thus obtained.

As described above, in the printing system of the second embodiment, since three inks of C, M, and Y are provided as chromatic color inks, the degree of freedom in selecting a tone to be applied to a monochrome image is increased. This is significantly improved compared to the printing system of the first embodiment, and a high-quality monochrome image can be printed accordingly. In addition, since each color ink of C, M, and Y is provided, a color image can be printed like a normal color printer by forming dots of these color inks mixed at an appropriate density. It has become.

Although various embodiments have been described above, the present invention is not limited to all of the above embodiments, and can be implemented in various modes without departing from the gist thereof. For example, a software program (application program) that realizes the above functions
May be supplied to a main memory or an external storage device of a computer system via a communication line and executed. Of course, a software program stored in a CD-ROM or a flexible disk may be read and executed.

In the above-described various embodiments, the size of the dots formed on the printing paper has been described as being constant. However, the size of the dots formed on the printing paper, such as a so-called variable dot printer, is described. The invention can be applied to a printer whose size can be controlled.

Further, in the various embodiments described above, the image data conversion processing is described as being executed in the computer. However, part or all of the image data conversion processing is performed by using the printer side or a dedicated image processing apparatus. May be executed.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram illustrating a software configuration of a computer as an image processing apparatus according to the present embodiment.

FIG. 3 is a schematic configuration diagram of a printer according to the present embodiment.

FIG. 4 is an explanatory diagram illustrating various ink cartridges.

FIG. 5 is an explanatory diagram illustrating a nozzle arrangement of the printer of the first embodiment.

FIG. 6 is a flowchart illustrating a flow of an image processing routine according to the first embodiment.

FIG. 7 is an explanatory diagram conceptually showing how dot density data for achromatic ink dots is calculated during the brightness conversion processing of the first embodiment.

FIG. 8 is an explanatory diagram illustrating a state in which a color tone to be given to a monochrome image is set in the first embodiment.

FIG. 9 is an explanatory diagram conceptually showing a state in which dots of chromatic ink are generated in the tone imparting process of the first embodiment.

FIG. 10 is an explanatory diagram illustrating a nozzle arrangement of the printer of the second embodiment.

FIG. 11 is a flowchart illustrating a flow of an image processing routine according to a second embodiment.

FIG. 12 is an explanatory diagram illustrating a state in which a color tone to be given to a monochrome image is set in the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 20 ... Printer 21 ... Scanner 23 ... Monitor 24 ... Modem 26 ... Hard disk 27 ... Memory card 30 ... Carriage motor 31 ... Drive belt 32 ... Pulley 33 ... Sliding shaft 34 ... Position detection sensor 35 ... Paper feed motor 36 ... Platen 40 ... Carriage 41 Printheads 42 and 43 Ink cartridges 44 to 49 Ink ejection head 60 Control circuit 61 CPU 62 ROM 63 RAM 80 Computer 81 CPU 82 ROM 83 RAM 88 SIO 90 Video Driver 91: Application program 92: Printer driver 120: Printer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C056 EA11 EC76 EC78 EC80 ED07 ED09 EE03 EE05 2C057 AF39 AF91 AH13 AM28 CA07 CA09 2C262 AA02 AA24 AB13 BA16 BA18 BA20 BB03 BB14 BB16 BB22

Claims (17)

[Claims] 1. A printing apparatus for printing a single-color image by forming a plurality of dots of achromatic ink on a print medium based on image data, comprising a plurality of achromatic inks having different densities, A chromatic color ink, and chromatic color dot forming means for forming dots of the chromatic color ink at a predetermined density according to brightness information included in the image data by mixing the dots of the achromatic color ink. A printing device characterized by the above-mentioned. 2. The printing apparatus according to claim 1, further comprising a first chromatic color ink and a second chromatic color ink having different hues from each other, wherein the chromatic color dot forming unit includes the first chromatic color dot forming unit. The dots of the first chromatic ink and the dots of the second chromatic ink are set such that the ratio between the dot density of the chromatic ink and the dot density of the second chromatic ink becomes a substantially constant value. A printing device as a means for forming. 3. The printing apparatus according to claim 1, wherein the chromatic inks are cyan ink, magenta ink, and yellow ink. 4. The printing apparatus according to claim 2, wherein the achromatic color dot forming unit that forms the plurality of achromatic color ink dots and the chromatic color dot forming unit are arranged on the print medium. A dot forming section for forming each dot of each ink, wherein the dot forming section forms the dots when a driving signal is received in a state where power for forming the dots is supplied. A power supply unit that supplies power to the dot forming units provided for the respective inks, and supplies the power to at least each of the dot forming units included in the chromatic color dot forming unit. A printing apparatus comprising a power supply unit supplied by a printer. 5. The printing apparatus according to claim 1, wherein the achromatic ink includes three types of inks having different densities. 6. The printing apparatus according to claim 1, wherein the plurality of achromatic inks include the same number or a large number of inks as the types of the chromatic inks. 7. An image processing apparatus for converting image data into an expression form based on the presence / absence of a plurality of types of dots, wherein the presence / absence of a plurality of types of achromatic dots having different densities is determined based on the image data. Achromatic color dot formation determining means, and chromatic color dot generating means for generating at least one type of chromatic color dots at a predetermined density in accordance with brightness information included in the image data by mixing the chromatic color dots with the achromatic color dots. An image processing apparatus comprising: 8. The image processing apparatus according to claim 7, wherein the chromatic color dot generation unit sets the first chromatic color dots and the second chromatic color dots having different hues in a density ratio of each other. An image processing device which is a means for generating a substantially constant value. 9. The image processing apparatus according to claim 8, further comprising: a density ratio setting unit that sets the ratio between the density of the first chromatic color dot and the density of the second chromatic color dot, The image processing apparatus, wherein the chromatic color dot generation unit is a unit that generates the first chromatic color dot and the second chromatic color dot at the set ratio. 10. The image processing apparatus according to claim 7, further comprising: a generation density setting unit configured to set the value of the predetermined density for generating the chromatic color dots. An image processing apparatus which is means for generating the chromatic dots at a predetermined density. 11. The image processing apparatus according to claim 7, further comprising: a density ratio setting unit that sets a ratio of dot formation densities for each color dot of a cyan dot, a magenta dot, and a yellow dot, The chromatic color dot generation means, at the set ratio,
An image processing apparatus which is a unit that generates the cyan dot, the magenta dot, and the yellow dot. 12. An ink container that is mounted on a printing device that receives supply of image data and ink and prints an image corresponding to the image data, and that stores ink to be supplied to the printing device. Achromatic dot forming means for forming dots with a plurality of achromatic inks having different densities; and A chromatic color dot forming means for forming the chromatic color dot at a predetermined density according to the printing device, comprising: Ink container. 13. The ink container according to claim 12, wherein the achromatic color dot forming means receives three types of achromatic color inks having different densities from each other, and forms dots by each of the achromatic color inks. The chromatic dot forming means is a means for receiving three types of chromatic inks of cyan ink, magenta ink, and yellow ink and forming dots by each ink. The ink container is a container that separately stores the three types of achromatic ink, the cyan ink, the magenta ink, and the yellow ink. 14. An ink container that is mounted on a printing device that receives supply of image data and ink and prints an image corresponding to the image data, and that stores ink to be supplied to the printing device. Achromatic dot forming means for forming dots of a plurality of achromatic inks having different densities, and mixing the dots of the chromatic ink with the dots of the achromatic ink to obtain lightness information contained in the image data. A chromatic dot forming unit that forms at a predetermined density according to the printing apparatus, wherein the ink container includes an ink storage unit that separately stores the plurality of achromatic inks used in the printing apparatus. An ink container capable of storing a larger amount of ink than the other achromatic inks for the ink having the lowest density among the plurality of achromatic inks. 15. An image processing method for converting image data into an expression form based on the presence / absence of a plurality of types of dots, wherein the presence / absence of a plurality of types of achromatic dots having different densities is determined based on the image data. And a process of mixing at least one type of chromatic color dot with the achromatic color dot and generating the same at a predetermined density in accordance with brightness information included in the image data. Method. 16. A computer-readable recording medium which records a program for converting image data into an expression format based on the presence / absence of a plurality of types of dots, wherein the presence / absence of a plurality of types of achromatic dots having different densities is determined. A function of making a determination based on image data; and a function of generating at least one type of chromatic dot at a predetermined density in accordance with brightness information included in the image data by mixing the chromatic dot with the achromatic dot. A recording medium characterized in that: 17. A program for converting image data into an expression form based on the presence / absence of a plurality of types of dots, a function of determining the presence / absence of a plurality of types of achromatic dots having different densities based on the image data. And a function of mixing at least one type of chromatic color dot with the achromatic color dot and generating the chromatic color dot at a predetermined density according to brightness information included in the image data.