JP2003154690A - Ink cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make high concentration and low concentration inks exist mixedly and to enhance a grade of printing, in regard to a cartridge for a printer conducting printing with high and low concentration inks. SOLUTION: Whether a dense dot is to be formed or not is judged from inputted gradation data by reference to a table of a recording rate of the ink of high concentration, and when it is judged to be formed, the dense dot is formed by driving a piezo element PE of a head for the ink. In the case when the dense dot is not to be formed, on the other hand, it is judged whether a dot is to be formed or not by the ink of low concentration, and turning on-off of a thin dot is determined so that an average recording rate by a prescribed value. Since formation of a thin dot is started in the region of the gradation data or below where the recording rate of the thin dot is the maximum, on the occasion, mixing of colors at a joint from recording with the thin dot to one with the dense dot is very smooth in the table referred to and the quality of printing can be made very high. The recording rate of the thin dot may be varied in conformity with the density of magenta at a position corresponding to the recording position of cyan ink.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing technique using dark and light inks, and more specifically, multi-gradation by controlling the distribution of each dot of two or more kinds of dark and light inks based on a gradation signal representing an image. The present invention relates to a printing apparatus for printing an image of the above, a cartridge used for the same, an image recording method, and a computer program product for realizing this method.

[0002]

2. Description of the Related Art Recently, as an output device of a computer,
Color printers of a type in which several colors of ink are ejected from a head have become widespread, and are widely used for printing images processed by computers and the like in multiple colors and multiple gradations. cyan,
When printing a multicolor image with three color inks, magenta and yellow (CMY), in such a printer, the size of the dots formed on the paper by the ink ejected at one time is constant, and the image to be printed is The gradation of is expressed by the density of dots (recording density per unit area).
The density of dots that can be formed per predetermined length is increasing year by year, but in the case of a printer, it is only about 300 dpi to 720 dpi, and there is still a large gap with the expressive power of silver halide photography. The resolution of silver circle film is said to be several thousand dpi.

In a printer that represents an image by the presence or absence of dots (also referred to as dot on / off), dots are sparsely formed in a region having a low image density, that is, a region having a low dot density to be printed. Because of the granularity, the dots are noticeable. Therefore, a printing apparatus and a printing method using dark and light inks have been proposed for the purpose of further improving the printing quality. This is to realize printing with excellent gradation expression by preparing high density ink and low density ink for the same color and controlling the ejection of both inks. For example, JP-A-6
Japanese Patent Laid-Open No. 1-108254 includes a head that forms two types of dots of different shades for the same color, and determines the number of shade dots formed in a predetermined dot matrix and their overlap according to the density information of the input image. A recording method and apparatus for recording a multi-gradation image by controlling are disclosed.

[0004]

However, in the conventional printing apparatus using the dark and light ink, how to correspond the high density ink and the low density ink to the gradation signal of the original image is pointed out. No particular consideration was given to the above, and the inks were simply assigned to the gradation signals of the image in order from the ink with the lowest density (for example, JP-A-2-215541, FIG. 9).

An object of the present invention is to provide a printing apparatus capable of ejecting two or more types of inks of different shades for the same color.
It is an object of the present invention to improve the quality of a recorded image by appropriately associating the high density ink and the low density ink with the gradation signal of the original image. In particular, one of the objects is to improve the expression of the low-density area in the original image or the expression of the area transitioning from the low-density area to the high-density area.
Furthermore, it is another object of the present invention to propose a cartridge suitable for such a printing apparatus.

[0006]

In order to achieve at least one of the above objects, the first printing device of the present invention uses the input means to input the gradation signal of the image to be printed. Based on this gradation signal, the dot generation means determines the recording density of dots of two or more types of dark and light ink. When determining the recording density of such dots,
The dot generation means is a gradation signal lower than the gradation signal that maximizes the recording density of dots of low-density ink, and based on the characteristic that dots of high-density ink appear,
Perform processing. As a result, the dots of the ink of the high density side start to be mixed before the recording density of the dots of the ink of the low density side reaches the maximum value, and a smoother gradation expression is realized.

Further, in the second printing apparatus of the present invention, the gradation signal of the image to be printed is inputted by the input means, and the dot generating means, based on the gradation signal, causes the dot generating means to generate inks of two or more kinds of light and shade. Find the recording density of the dots. In determining the recording density of such dots, in this printing apparatus, the dot generating means causes the dots of the low-density ink to be used when the gradation signal is higher than the gradation signal that maximizes the recording density of the dots of the low-density ink. The processing is performed based on the characteristic that the recording density of is sharply reduced. As a result, when the recording density of the low-density ink dots exceeds the maximum value and the high-density ink dots start to mix, the low-density ink dot recording density drops sharply. , Smoother gradation expression is realized.

In such a printing apparatus using the dark and light ink, the dot generating means has a table for giving the recording density of each dot of the dark and light two or more kinds of the ink from the inputted gradation signal, which facilitates the calculation. It is suitable for

Further, when the dark and light ink is composed of two kinds of ink, if the dye density of the low density ink is set to about 1/4 of the dye density of the high density ink, the gradation change of the actually printed one is the most. It feels smooth.

As a head of such a printing apparatus, a head capable of ejecting two or more kinds of dark and light inks for a plurality of inks having different hues is provided, and the dot generating means is provided for each of at least two kinds of inks having different hues. It is also preferable to provide each color dot generation means for performing the processing for obtaining the recording density of each dot. In this case, appropriate dark and light ink dots can be generated for inks of a plurality of hues. The plurality of inks having different hues include cyan and magenta inks. In this case, each color dot generation means can be a means for performing the above-mentioned processing for cyan and magenta.

Further, the dot forming means for each color can be configured to determine the recording density of the dots in association with the data of ink of another hue ejected to the corresponding pixel. In this case, the recording density of the dots of the light ink can be changed as compared with the case of a single color, and more appropriate dots can be formed in the case of color printing. In particular, if each color dot generation unit corrects the dot recording density of the low-density ink to be lower as the density of the other hue ink ejected to the corresponding pixel is higher, a plurality of color inks are ejected. In the portion where the ink is discharged, the discharge amount of the ink having a low density can be reduced, and the ink amount per unit area can be reduced as a whole. As a result, it is possible to perform printing with a margin with respect to the limit (ink duty) of the ejectable ink amount per unit area of the paper.

Various configurations can be adopted for the ink ejection method, and a mechanism for ejecting ink particles by a pressure applied to the ink by applying a voltage to an electrostrictive element provided in the ink passage is provided. A configuration or a configuration including a mechanism for ejecting ink particles by the pressure applied to the ink in the ink passage by the bubbles generated by the energization of the heating element provided in the ink passage can be adopted. According to these configurations, it is easy to make the ink particles fine and to control the amount of the ink appropriately, and it is also easy to prepare a large number of ejection nozzles on the head. When a large number of nozzles are provided, the nozzles for ejecting ink particles are provided for each color and each density of ink.
A plurality of sheets can be arranged along the conveying direction of the printed paper. By preparing a plurality of nozzles, it is possible to contribute to the improvement of printing speed.

The third printing apparatus of the present invention is capable of ejecting a plurality of inks having different hues, and for at least one of the plurality of inks, a head capable of ejecting two or more kinds of dark and light inks. When the gradation signal of the image to be printed is input, based on the input gradation signal,
The recording densities of the respective dots of the plurality of inks having different hues are obtained, and the light ink of the two or more kinds of dark and light inks is associated with the densities of inks of other hues ejected to the corresponding pixels, Determine the dot density. Therefore, the recording rate of low-density ink is also related to the densities of inks of other hues.

The relationship between the recording rate of the low density ink and the density of the ink of another hue is as follows: the higher the density of the other color ink ejected to the corresponding pixel is, the recording density of dots by the low density ink. You can think of a relationship that lowers. In this case, the recording rate of the low-density ink can be reduced and the restriction on the ink duty can be relaxed within a range in which the apparent image quality is little affected.

It is also effective to have a look-up table that directly obtains the recording rate of dark and light dots for a plurality of inks of different hues from the hue data of the original image, in order to speed up the processing for obtaining the recording rate. is there.

The invention of the ink cartridge used in the above-mentioned printing apparatus is characterized in that two or more kinds of dark and light color inks having different densities are contained in a container separate from the black ink. Since this ink cartridge is stored in a container separate from the black ink, the replacement time is affected by the exhaustion of the black ink used for printing mainly on normal characters and the replacement time. Never.

In such an ink cartridge, two or more kinds of dark and light inks having the same hue but different densities can be arranged at positions adjacent to each other. , A cyan ink in order from one end, an ink having a lower dye concentration than the cyan ink,
It is possible to arrange the magenta ink, the ink having a lower dye concentration than the magenta ink, and the yellow ink in this order.

Further, the first image recording method of the present invention is provided with a head capable of ejecting two or more kinds of inks having different densities of different densities, respectively, and the two or more kinds of light and shades based on the gradation signal of the image to be recorded. Is a method of recording a multi-gradation image by controlling the distribution of ink dots, and from the range of gradation signals lower than the gradation signal at which the recording density of dots with low-density ink is the maximum value, The characteristic that dots of high-density ink appear is stored, the gradation signal of the image to be printed is input, and according to the stored characteristic, from the input gradation signal, the dots of two or more types of dark and light ink The gist is to determine the presence / absence of each of the dots, control the ejection of ink from the head according to the presence / absence of the determined dots, and perform gradation expression depending on the presence / absence of dots of two or more types of the dark and light inks.

The second image recording method of the present invention is provided with a head capable of ejecting two or more kinds of inks having different densities of different shades, respectively, and the two kinds of shades are produced based on the gradation signal of the image to be recorded. This is a method of recording a multi-gradation image by controlling the distribution of ink dots, and a low gradation signal with a density lower than the gradation signal that maximizes the recording density of dots with low-density ink The characteristic that the recording density of the dots with the density ink is sharply reduced is stored, the gradation signal of the image to be printed is input, and in accordance with the stored characteristic, from the input gradation signal, two or more of the light and shade types are input. It is necessary to determine the presence or absence of each dot of ink, control the ejection of ink from the head according to the presence or absence of the determined dot, and perform gradation expression by the presence or absence of dots of two or more types of dark and light ink. It is set to.

The third image recording method of the present invention is an image recording method for recording an image by controlling the distribution density of dots formed by inks of different hues, and a plurality of inks of different hues. Can be ejected, and for at least one of the plurality of inks, a gradation signal of an image to be printed is input using a head capable of ejecting two or more types of dark and light ink, and the input gradation Based on the signal
The recording densities of the respective dots of the plurality of inks having different hues are obtained, and the light ink of the two or more kinds of dark and light inks is associated with the densities of inks of other hues ejected to the corresponding pixels, Determine the dot density,
The gist of the invention is to control the ejection of ink from the head to record dots of a plurality of inks of different hues and inks of two or more kinds of light and shade on the recording medium.

In the first recording medium of the present invention, a head capable of ejecting two or more kinds of inks having different densities of different densities is driven, and the two or more kinds of the densities of two or more kinds are printed based on the gradation signal of the image to be printed. A recording medium in which at least a part of a program for controlling a distribution of ink dots to form a multi-tone image is recorded so that it can be read by a computer, and the recording density of dots with low-density ink has a maximum value. A table storing characteristics of appearance of dots of high-density ink from a range of gradation signals lower than the gradation signal, and a first program for inputting gradation signals of an image to be printed; According to the characteristics described above, a second program for determining the presence or absence of each of the two or more types of ink dots of the light and shade based on the input gradation signal is recorded. .

In the second recording medium of the present invention, a head capable of ejecting two or more kinds of light and shade having different densities is driven, and the two kinds of light and shade are printed based on the gradation signal of the image to be printed. A recording medium in which at least a part of a program for forming a multi-gradation image by controlling the distribution of ink dots described above is recorded in a computer-readable manner, and the recording density of dots with low-density ink is For a gradation signal higher than the maximum gradation signal, a table storing characteristics that the recording density of dots with low-density ink sharply decreases and a gradation signal of an image to be printed are input. A program and a second program for respectively determining the presence or absence of the dots of the two or more kinds of the light and shade inks from the input gradation signal according to the stored characteristics are recorded. It is the gist.

Further, the third recording medium of the present invention is capable of ejecting a plurality of inks having different hues, and at least one of the plurality of inks is capable of ejecting two or more kinds of light and shade. A recording medium in which at least a part of a program for recording an image by driving a head and controlling the distribution density of dots formed by the inks of different hues is recorded by a computer,
A first program for inputting a gradation signal of an image to be printed and the recording density of each dot of a plurality of inks having different hues are calculated based on the input gradation signal, and the density of two or more shades is calculated. Regarding the light ink of the inks, it is summarized that a second program for determining the density of dots is recorded in association with the densities of inks of other hues ejected to the corresponding pixels.

As these recording media, RO is used.
Various media such as M, RAM, flexible disk, CD-ROM, memory card, and other magneto-optical disk can be considered. Of course, it also includes a paper on which a bar code or the like is recorded and a card on which punch holes or the like are punched according to a predetermined code system. Further, the above-described recording medium has a program recorded for determining the presence / absence of dots and the dot density, but a program for controlling ink ejection in the head according to the presence / absence of determined dots and the determined dot density is used. This is because when the printer or the computer is prepared in the form of firmware in advance, it is sufficient for the program prepared in the recording medium to determine the presence or absence of dots and the dot density. When these firmwares are not prepared or when a program corresponding to these processes is prepared, a signal to control the ejection of ink from the head is output according to the presence or absence of the determined dots and the dot density. Alternatively, the third program may be recorded together with the recording medium.
Note that these first to third programs do not have to be recorded in a single recording medium, and may be recorded separately in several separated media. Of course,
It is also possible to carry out predetermined encryption and compression before recording.

[0025]

Other Embodiments of the Invention The present invention also includes the following other embodiments. One of them is a configuration in which the input unit and the dot generation unit of the printing apparatus are placed not on the inside of the housing of the printing apparatus but on the side of the apparatus that outputs the image to be printed.
The dot generation means can be realized by a discrete circuit, but can also be realized by software in an arithmetic logic operation circuit centering on a CPU. In the latter case, the side that outputs the image to be printed, for example, the computer side, is made to perform the process related to dot generation, and the generated dots are ejected from the head in the housing of the printing apparatus. It is also possible to consider a mode in which only the mechanism that is controlled and formed on the paper is stored. Of course, it is also possible to divide the function of the dot generation means into several parts, realize some of them in the housing of the printing apparatus, and implement the rest on the side that outputs the image.

As another form, a form as a supply device for supplying the program for realizing the above image recording method or the program recorded in the above recording medium via a communication line can be considered. In such a form, the image recording method described above can be realized by placing the program on a server or the like on the network, downloading the necessary program to the computer via the communication line, and executing the program.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described based on examples. As shown in FIG. 1, a printing apparatus 10 according to an exemplary embodiment of the present invention includes a computer 90 and a printer 20 connected to the computer 90. The scanner 90 is further connected to the computer 90,
By loading and executing a predetermined program on the computer 90, the whole functions as the printing apparatus 10 having an image reading function. As shown,
The computer 90 includes a CPU 81 that executes various arithmetic processes for controlling operations related to image processing according to a program, and includes the following respective units interconnected by a bus 80. The ROM 82 stores in advance programs and data necessary for the CPU 81 to perform various arithmetic processes, and the RAM 83 temporarily reads and writes various programs and data required for the CPU 81 to perform various arithmetic processes. It is the memory that is used. The input interface 84 controls the input of signals from the scanner 12 and the keyboard 14, and the output interface 85 controls the output of data to the printer 20. The CRTC 86 controls signal output to the CRT 21 capable of color display, and the disk controller (DDC) 87 controls the hard disk 16
Or flexible drive 15 or CD (not shown)
It controls the exchange of data with the ROM drive. The hard disk 16 stores various programs loaded and executed in the RAM 83, various programs provided in the form of device drivers, and the like. other than this,
The bus 80 has a serial input / output interface (SI
O) 88 is connected. The SIO 88 is connected to the modem 18, and is connected to the public telephone line PNT via the modem 48. The computer 90 is connected to an external network via the SIO 88 and the modem 18, and by connecting to a specific server SV, it is possible to download the program necessary for image processing to the hard disk 76. In addition, the necessary programs can be stored on the flexible disk FD or C.
It is also possible to load it by the D-ROM and make the computer 90 execute it.

As shown in FIG. 2, the printer 20 has a mechanism for conveying the paper P by a paper feed motor 22, and a carriage motor 24 for moving the carriage 30 to a platen 26.
And a mechanism for driving the print head 28 mounted on the carriage 30 to control ink ejection and dot formation, and the paper feed motor 2
2, a carriage motor 24, a print head 28, and a control circuit 40 that controls signals with the operation panel 32.

The mechanism for conveying the paper P is the paper feed motor 2
A gear train for transmitting the rotation of 2 to not only the platen 26 but also a sheet conveying roller (not shown) is provided (not shown). Further, the mechanism for reciprocating the carriage 30 is such that an endless drive belt 36 is stretched between a carriage shaft 24 and a slide shaft 34 that is installed in parallel with the shaft of the platen 26 and slidably holds the carriage 30. Pulley 38 to
Position detection sensor 3 for detecting the origin position of the carriage 30
It is composed of 9 etc.

The configuration of the printer 20 centering on the control circuit 40 will be described with reference to FIG. As shown,
The control circuit 40 includes a well-known CPU 41, a P-ROM 43 for storing programs and the like, a RAM 44, and a character generator (C for storing a dot matrix of characters).
G) The I / F dedicated circuit 50, which is configured as an arithmetic and logic operation circuit centered around 45 and the like, and which exclusively interfaces with an external motor or the like, and the head connected to the I / F dedicated circuit 50. A head drive circuit 52 for driving the motor 28 and a motor drive circuit 54 for driving the paper feed motor 22 and the carriage motor 24 are also provided. Also,
The I / F dedicated circuit 50 has a built-in parallel interface circuit, is connected to the computer through the connector 56, and can receive a printing signal output from the computer. The output of the image signal from the computer will be described later.

Next, the specific structure of the carriage 30 and the principle of ink ejection by the print head 28 mounted on the carriage 30 will be described. As shown in FIG. 4, the carriage 30 is substantially L-shaped, and includes a black ink cartridge and a color ink cartridge 70 (not shown).
And a partition plate 31 for partitioning both cartridges so that they can be mounted. As shown in FIG. 5, a total of six ink ejecting heads 61 to 66 are formed on the print head 28 below the carriage 30, and the ink tanks are connected to the heads for the respective colors at the bottom of the carriage 30. Introducing pipes 71 to 76 for guiding the ink are erected. When the black ink cartridge and the color ink cartridge 70 are mounted on the carriage 30 from above, the introduction pipes 71 to 76 are inserted into the connection holes provided in each cartridge.

A mechanism for ejecting ink will be briefly described. When the ink cartridge 70 shown in FIG. 6 is mounted on the carriage 30, the ink in the ink cartridge is sucked out through the introduction tubes 71 to 76 by utilizing the capillary phenomenon, and as shown in FIG. Each color head 61 to 6 of the print head 28 provided on the lower portion of the carriage 30.
Guided to 6. As shown in FIGS. 5 and 7, each color head 61 to 66 is provided with nozzles n for each color in a line. In this embodiment, the number of nozzles for each color is 32. A piezo element PE is arranged for each nozzle n. As is well known, the piezo element PE is an element which has a crystal structure which is distorted by application of a voltage and which converts electric-mechanical energy at extremely high speed. Piezo element PE and nozzle n
The structures of and are shown in detail in FIGS. 8 (A) and 8 (B).
Is. As shown in the figure, the piezo element PE has a nozzle n.
It is installed at a position in contact with the ink passage 68 that guides the ink. In this embodiment, by applying a voltage of a predetermined time width between the electrodes provided at both ends of the piezo element PE, the piezo element PE is rapidly expanded and the ink passage is expanded, as shown in FIG. 8B. One side wall of 68 is deformed. As a result, the volume of the ink passage 68 contracts in accordance with the expansion of the piezo element PE, and the ink corresponding to this contraction becomes particles Ip and is ejected from the tip of the nozzle n at high speed.
The paper P on which the ink particles Ip are mounted on the platen 26
By soaking in, printing is performed.

The arrangement of the heads 61 to 66 of the respective colors in the print head 28 is divided into three groups as shown in FIG. 5, because of the arrangement of the piezo elements PE. Has been done. A black ink head 61 is arranged at the end close to the black ink cartridge, and a cyan ink head 62 is adjacent to the black ink head 61. Adjacent to this set are a head 63 for ink having a lower density than the cyan ink supplied to the cyan ink head 62 (hereinafter referred to as light cyan ink) and an ink head 64 for magenta. Further, in a group next to it, a head 65 for ink having a lower density than normal magenta ink (hereinafter referred to as light magenta ink),
A yellow head 66 is arranged. The composition and density of each ink will be described later.

In the printer 20 of the present embodiment having the above-described hardware structure, the platen 26 and other rollers are rotated by the paper feed motor 22 to convey the paper P, while the carriage 30 is reciprocated by the carriage motor 24. At the same time, the piezo elements PE of the heads 61 to 66 of the respective colors of the print head 28 are driven to eject the inks of the respective colors and form a multicolor image on the paper P. As shown in FIG. 9, the printer 20 forms a multicolor image based on a signal received from an image forming apparatus such as a computer 90 via the connector 56. In this example, the application program operating inside the computer 90 performs image processing while performing video processing.
An image is displayed on the CRT display 93 via the display 1. When this application program 95 issues a print command, the printer driver 9 of the computer 90
6 receives the image information from the application program and converts it into a signal printable by the printer 20. In the example shown in FIG. 9, inside the printer driver 96, a rasterizer 97 for converting image information handled by the application program 95 into color information in dot units, image information converted into color information in dot units (floor) Image output device (here, the printer 2
0) A color correction module 98 for performing color correction according to the color development characteristic, and so-called halftone image information expressing the density in a certain area depending on the presence or absence of ink in dot units from the image information after color correction. A generating halftone module 99 is provided. Since the operation of each of these modules is well known, the description thereof will be omitted in principle, and the content of the halftone module 99 will be described as necessary.

As described above, in the printer 20 of the present embodiment, the print head 28 has a so-called CMYK 4 printer.
In addition to the color inks, heads 63 and 65 for light cyan ink and light magenta ink are provided. These inks are obtained by reducing the dye concentration of ordinary cyan ink and magenta ink, as shown in FIG. As shown in the figure, the normal density cyan ink (see FIG.
0 is shown as C1) is a direct blue 19 which is a dye.
3.6% by weight of diethylene glycol 30
10% by weight, Surfynol 465 was 1% by weight, and water was 65.4% by weight, while light cyan ink (denoted by C2 in FIG. 10) was used.
Direct Blue 199 which is a dye, cyan ink C
0.9% by weight, which is 1/4 of 1, and 35% by weight of diethylene glycol for viscosity adjustment,
The water was changed to 63.1 weight percent. In addition, magenta ink of normal density (indicated by M1 in FIG. 10)
The dye is Acid Red 289 at 2.8 weight percent, diethylene glycol at 20 weight percent, Surfynol 465 at 1 weight percent and water at 76.2 weight percent, while light magenta ink (Fig. 10). (Indicated by M2 in the middle) indicates that acid red which is a dye is 0.1% which is 1/4 of the magenta ink M1.
It was changed to 7 weight percent, diethylene glycol 25 weight percent, and water 73.3 weight percent.

As shown in FIG. 10, the yellow ink Y and the black ink K use direct yellow 86 and hood black 2 as dyes, respectively, and are 1.8.
The weight percent is 4.8 weight percent. Both inks have a viscosity of about 3 [mPa · s].
It is adjusted to the extent. Since the viscosities are adjusted to be the same, the control of the piezo element PE for each color head can be made the same.

FIG. 11 shows the measured lightness of each color ink. The horizontal axis of FIG. 11 is the recording rate with respect to the recording resolution of the printer, and shows the rate of recording dots on the white paper P by the ink particles Ip ejected from the nozzles n. That is, the recording rate 100 indicates a state in which the entire surface of the paper P is covered with the ink particles Ip. In this embodiment, the light cyan ink C2 has a dye concentration of about 1/4 in terms of weight percentage with respect to the cyan ink C1, and the lightness of both inks at this time is 100% when the recording rate of the light cyan ink C2 is 100%. The brightness of
It is equal to the brightness when the recording rate of the cyan ink C1 is about 35%. This relationship also applies to the magenta ink M1 and the light magenta ink M2. The recording rate ratio at which the inks having different densities have the same lightness is determined from the viewpoint of the beauty of color mixing when both inks are mixed and printed, but in practice, it is 20 to 50.
It is desirable to adjust to the range of percentage. When this relationship is expressed by the ratio of the weight percent of the dye in both inks, the ink of the low density (light cyan ink C2 and light magenta) is compared with the weight percent of the dye in the high density ink (cyan ink C1 and magenta ink M1). Regarding the relationship of the weight percentage of the dye in the ink M2), the latter is about 1/5 to 1/3 of the former.
It is almost equivalent to adjusting to a certain degree.

Next, along with the processing in the halftone module 99 of the printer driver 96, the printing state using the dark and light inks in the printer 20 of this embodiment will be described. FIG. 12 is a flowchart showing an outline of the processing of the halftone module 99.

As shown in the figure, when the printing process is started, each pixel is sequentially scanned with the upper left corner of one image as the origin, and the color correction module 98 first causes the carriage 3 to move.
The color-corrected gradation data DS (8 bits for each of CMYK) of one pixel is input in order along the scan direction of 0 (step S100).

In the following description, it is assumed that printing is performed only with cyan ink, but in reality, multicolor printing is performed, and with regard to magenta,
Dark dots and light dots are formed by the high density magenta ink M1 and the low density light magenta ink M2. For yellow, dots are formed by yellow ink Y, and for black, black ink K.
Thus, dots are formed. Further, when dots of different color inks are formed in a predetermined area, control necessary for improving color reproducibility by color mixture, for example, printing different color dots at the same position It is controlled not to do so.

Next, based on the input gradation data DS,
A process for determining ON / OFF of the dark dot is performed (step S120). The details of the processing for determining the on / off of the dark dot will be described according to the dark dot formation determination processing routine of FIG. In this processing routine, first, based on the gradation data DS, the table shown in FIG. 14 is referred to, and processing for generating the dark level data Dth is performed (step S122). FIG. 14 shows a table for setting the recording rates of the light ink and the dark ink with respect to the gradation data of the original image. Since the gradation data has a value of 0 to 255 for each color (8 bits for each color), the size of the gradation data is 16/2.
Expressed as 56 etc. The table of FIG. 14 shows the average ratio of dark ink and light ink in the obtained printed matter, and the average recording of dark ink and light ink that should be realized when given gradation data DS. Give a rate. Therefore, the on / off of the dots of the dark ink or the light ink of each pixel is not uniquely determined.

Based on the input gradation data DS, FIG.
By referring to the table of No. 4, dark level data Dth corresponding to a predetermined dark ink recording rate is obtained (right vertical axis in FIG. 14). For example, when printing a solid area where the input cyan gradation data is 50/256, the recording rate of the cyan ink C1 that is dark ink is 0%, and the dark level data is also 0. Gradation data is 95
When printing a solid area of / 256, the recording rate of the cyan ink C1 which is a dark ink is 7%,
The dark level data Dth has a value of 18. Further, when printing a solid area with gradation data of 191/256, the recording rate of the cyan ink C1 is 75%, and the dark level data has the value 191. The recording rates of the corresponding light cyan ink C2 in these cases are 36%, 58%, and 0%, and the light level data Dtn is 92/255, 148 /, respectively.
It becomes 255,0 / 255.

Further, the relationship between the recording rate of the light cyan ink C2 and the recording rate of the cyan ink C1 shown in FIG.
It has the following features. (1) Area where input gradation data is low (0 in the embodiment)
/ 256 to 63/256), only the light cyan ink C2 is recorded. The recording rate monotonically increases according to the size of the gradation data. (2) Even before the recording rate of the light cyan ink C2, which becomes a large value in accordance with the increase in the input gradation data, reaches the maximum value (58% in the embodiment), in accordance with the increase in the gradation data, The formation of dots by the cyan ink C1 having a high density is started, and the recording rate is gradually increased. In the embodiment, the input gradation data is 63 /
When it exceeds 256, dots are formed by the cyan ink C1. The value of the gradation data that maximizes the recording rate of the light cyan ink C2 is 95/256 in the embodiment.

(3) When the gradation data becomes larger than the maximum value of the recording rate of the light cyan ink C2, the recording rate of the light cyan ink C2 decreases rapidly. On the other hand, the recording rate of the cyan ink C1 increases almost in proportion to the increase in gradation data. In the embodiment, the gradation data is 127/2.
When it exceeds 56, the recording rate of the light cyan ink C2 sharply decreases, and when the gradation data exceeds 191/256, the recording rate becomes almost zero. (4) In the area where the gradation data is larger than the value at which the recording rate of the light cyan ink C2 is almost 0, the cyan ink C1
The recording rate of increases sequentially up to a maximum value of 100% according to the increase of the gradation data, but compared to the area before that, the ratio of the increase of the recording rate to the increase of the gradation data is
It is getting a little low.

In this embodiment, the dark level data Dth is obtained by using this relationship shown in FIG.
The following processing for determining off is performed. First, it is determined whether the dark level data Dth thus obtained is larger than the threshold value Dref1 (FIG. 13, step S12).
4). This threshold value Dref1 is a determination value of whether or not to form a dot of dark ink on the pixel of interest. In this example, a threshold matrix of distributed dither is adopted for setting the threshold, and in particular, a global matrix (blue noise matrix) of about 64 × 64 is used and the systematic dither method is applied. Therefore, the threshold value Dref1 that determines on / off of the dark dot has a different value for each pixel of interest. Figure 1
Fig. 5 shows the concept of the threshold in the systematic dither method. In FIG. 15, the size of the matrix is 4 × 4 for convenience of illustration.
However, in practice, a 64 × 64 matrix is used, and the threshold is determined so that there is no bias in the appearance of the threshold (0-255) in any 16 × 16 region inside the matrix. . The use of such a global matrix suppresses the occurrence of false contours and the like. The dispersed dither is a type in which the spatial frequency of dots determined by the threshold value matrix is high, and the dots are scattered in the area. Specifically, a Beyer type threshold matrix and the like are known. When the dispersion type dither is adopted, since the dark dots are generated in a random manner, the distribution of the dark and light dots is not biased, and the image quality is improved. It should be noted that other methods such as a density pattern method and a pixel distribution method may be adopted to determine ON / OFF of the dark dots.

When the dark dot data Dth is larger than the threshold value Dref1, it is determined that the dark dot of the pixel is turned on, and the result value RV is calculated (FIG. 1).
3, step S126). The result value RV is a value (dark dot evaluation value) corresponding to the density of the pixel, and when it is determined that the dark dot is on, that is, a dot with high density ink is formed in the pixel, the density of the pixel Corresponding value (for example, value 255) is set. This result value RV
May be a fixed value, or may be set as a function of the dark level data Dth.

On the other hand, the dark level data Dth is the threshold value Dref1.
In the following cases, it is determined that the dark dot is off, that is, it is not formed, and the value 0 is substituted for the result value RV (step S128). Since the white background of the paper remains at the portion where dots of high density ink are not formed, the result value RV is set to 0.

Thus, the on / off of the dark dot is determined,
Processing for calculating result value RV (FIG. 12, step S120)
Then, the process for obtaining the light dot data Dx for determining ON / OFF of the light dot is performed (step S130), and the diffusion error ΔDu from the processed pixel is added to this to obtain the correction data. A process for obtaining DC is performed (step S135). The light dot data Dx is obtained by the following equation. Dx = Dth.Z / 255 + Dtn.z / 255 Here, Dtn is light dot data obtained from the gradation data DS based on the graph of FIG. Also, Z is
It is an evaluation value when a dark dot is formed, and here, as described above, the value is 255. Therefore, the above equation becomes Dx = Dth + Dtn · z / 255. Further, z is an evaluation value when light dots are formed. In the case of a light dot, even if a dot is formed, its evaluation is smaller than that of a dark dot. In this embodiment, z = 160.

The reason why the correction data DC is obtained by adding the diffusion error ΔDu to this is that the error diffusion processing is performed for the light dots. When printing is performed by error diffusion, the shading error that has occurred in a processed pixel is pre-allocated with a predetermined weight attached to the pixels around the pixel. Therefore, the corresponding error amount is read out and reflected on the pixel to be printed from now on. FIG. 16 exemplifies how the peripheral pixels are weighted and how much the error is distributed to the processed pixels PP for which ON / OFF of the light dots is determined.
For the pixel PP that has been determined to be on / off, the carriage 3
With respect to several pixels in the scanning direction of 0 and adjacent several pixels on the rear side in the conveyance direction of the paper P, the density error has a predetermined weight (1
/ 4, 1/8, 1/16) is allocated.

After obtaining the correction data DC, it is judged whether or not the dark dot is turned on (dot formation by the cyan ink C1) (step S138). If the dark dot is not formed, the density is low. A process for determining on / off of dots, that is, dots of light cyan ink C2 (hereinafter, referred to as light dots) is performed (step S140).
FIG. 17 shows the process of determining whether the light dots are turned on or off.
The light dot formation determination processing routine shown in FIG. In the process of determining the on / off of the light dot, the dot formation by the light cyan ink C2 is
The error diffusion method is applied to determine whether the gradation data DC corrected by the error diffusion concept is larger than the light dot threshold Dref2 (step S144). This threshold Dref2
Is a determination value of whether or not to form a dot of low density light ink in the pixel of interest, and is a fixed value 127 in this embodiment. It is also possible to set this threshold value Dref2 as a value that is variable according to the corrected data DC. For example, if the threshold Dref2 is a function of the correction data DC to be determined and the threshold Dref2 is set to the minimum value and the maximum value near the minimum value and the maximum value of the correction data DC, respectively, the gradation It is possible to suppress the delay of dot formation near the lower limit or the upper limit, and the disturbance of dot formation (so-called tailing) that occurs within a certain range in the scanning direction when the gradation of the area changes abruptly.

If the correction data DC is larger than the threshold value Dref2, it is determined that the light dot is turned on, and the result value RV (light dot evaluation value) is calculated (step S146). Result value RV
Is the correction value DC using the value 122 as the reference value.
Although the value is corrected by the above, it may be a fixed value. On the other hand, when it is determined that the correction data DC is less than or equal to the threshold value Dref2, it is determined that the light dot is turned off, and the value 0 is included in the result value RV (step S14).
8).

Thus, turning on / off the light dot and the result value R
After calculation of V (step S14 in FIG. 12).
0), and then error calculation is performed (step S150). The error calculation is obtained by subtracting the result value RV from the correction data DC. When neither dark nor light dots are formed, the result value RV is set to the value 0, so the correction value DC is included in the error ERR. That is, since the density to be realized in that pixel was not obtained at all, the density is calculated as an error. On the other hand,
When a dark dot or a light dot is formed, the result value RV corresponding to each dot is substituted, so the difference from the data DC that is the basis of the determination becomes the error ERR.

Next, error diffusion processing is performed (step S160). A predetermined weight (see FIG. 16) is added to the error obtained in step S150, and the error is diffused to the peripheral pixels of the pixel being processed. After the above processing, the process moves to the next pixel and the processing of step S100 and subsequent steps described above is repeated.

In this way, recording is performed using light dots and dark dots. This state is shown in the cyan ink C1.
FIG. 18 schematically shows the light cyan ink C2 and the light cyan ink C2. An area where the input gradation data is low (in the embodiment, the gradation data is 0/256 to 63/256).
18A and 18B, only the dots of the light cyan ink C2 are formed, and as the gradation data becomes higher, the ratio of the light dots existing in the predetermined area becomes Increase.

In an area where the gradation data exceeds a predetermined value (in the embodiment, an area of 64/256 or more), as shown in FIG. 18C, the ratio of light dots also increases, but recording of dark dots also starts. Is gradually increased. Further, in the region where the gradation data is high (the region of 95/256 or more in the embodiment), the dark dots increase and the ratio of the light dots decreases as shown in FIGS. 18D and 18E. Go.

Area with higher gradation data (1 in the embodiment)
In the area of 91/256 or more), light dots are not formed, and only dark dots are formed as shown in FIGS. 18 (f) and 18 (g). When the gradation data is maximum, as shown in FIG. 18 (h), the recording rate of dark dots becomes 100%, and the entire surface of the paper P is printed with high-density ink (cyan ink C1). .

As described above, since the printer 20 using the dark and light inks of this embodiment records an image using two kinds of inks having dye concentrations different by about 4 times, it is particularly effective in a low gradation region. The print quality is improved mainly by eliminating the graininess. Moreover, as shown in FIG. 14, an ink having a high density (cyan ink C1 in FIG. 14) is formed from an area below the gradation data at which the recording rate of the light dot is the maximum with the ink having a low density (light cyan ink C2 in FIG. 14). Since the formation of dark dots is started by means of, the color mixing at the joint from the recording of light dots to the recording of dark dots is extremely smooth, and the printing quality is extremely high.

Further, since the dot formation by the dark ink is started from the area below the gradation data where the recording rate of the light ink is maximum, the maximum recording rate of the light ink is about 60%. be able to. As a result, there is no occurrence of a solid-painted state with light ink in a low gradation region, and it cannot be said that pseudo contours occur in gradations in this vicinity. In addition, the degree of freedom in the distribution of dots by the dark ink is high, and it is possible to obtain a clean distribution that does not look strange. As a result, the expression in the vicinity of the gradation at which the high density ink and the low density ink start to mix is extremely natural.

Further, in the area larger than the gradation where the recording rate of the light ink is maximum, the recording rate of the light ink is rapidly lowered. Therefore, as the gradation increases, the light ink dots will be replaced with the dark ink dots, and the number of ink dots required to express the same gradation, that is, the ejection amount, will decrease, and as a whole The amount of ink used can be reduced. As a result of the rapid decrease in the recording rate of the light ink, the recording rate of the light ink becomes almost 0 long before the recording rate of the dark ink reaches 100% (input data 255). Therefore, when printing a region where the gradation of an image is dark, not only is light ink wasted unnecessarily, but the amount of ink ejected as a whole can be reduced, so that the amount of ink per unit area of the paper can be reduced. It is also preferable from the viewpoint of limitation.

The relationship between the size of the gradation data and the recording rates of the light ink and the dark ink is not limited to that shown in FIG. 14, and for example, as shown by straight lines Jc1 and Jc2 in FIG. The gradation data at which the formation of dots is started is set to a value much lower than that in the above-described embodiment, and as shown by broken lines Bc1 and Bc2 in FIG. It is also possible to adopt a characteristic in which the value of the key data is a value considerably larger than that in the above-mentioned embodiment. Further, as shown in FIG. 20, it is also possible to adopt a characteristic of reducing the recording rate of the light ink in an area equal to or higher than the gradation data where the recording rate of the light ink becomes the maximum value at an extremely large rate.

Further, in this embodiment, since the black ink cartridge and the color ink cartridge 70 are separated, the black ink, which is often used for printing characters, and the color ink are exchanged at the same time. There is no need to say that the ink cartridge 70 must be replaced. The color ink array in the color ink cartridge 70 is such that inks of the same color (cyan or magenta) and different in density are adjacent to each other, and the physical distances from high density ink to low density ink are the same for each ink. ing. Therefore, the dot position can be accurately controlled when both dark and light inks are printed. Further, in this embodiment, since a large number of nozzles are prepared along the transport direction of the paper P, high-speed printing is possible as a whole.

Although one embodiment of the present invention has been described above, the present invention is not limited to such an embodiment and can be implemented in various modes without departing from the scope of the present invention. Of course. For example, it is possible to use three or more types of ink having different densities.
In this case, the ratio of the dye concentration of the ink may be a geometric series (1: n: 2 × n ··) or a power relation (1: n2: n4 ··). Here, n = 2, 3 ...

In this embodiment, two kinds of inks having different densities are prepared only for cyan and magenta.
For yellow and black, it is also possible to use inks having different densities in combination. Ink is CMY
It is not limited to the combination of K, and may be applied to other combinations, and it is also possible to use two or more kinds of inks having different densities for special colors such as gold and silver.

In this embodiment, the program for controlling the light and shade dots is prepared not on the printer 20 side but on the printer driver 96 side of the computer 90, but it is also possible to prepare it in the printer 20. For example, when image information to be printed in a language such as Postscript is sent from the computer 90, the printer 2
The halftone module 99 and the like will be provided on the 0 side. Further, in the present embodiment, a software program for realizing these functions is stored in a hard disk or the like in the computer 90, and is incorporated in the operating system in the form of a printer driver when the computer 90 starts up. And CD-RO
Is stored in a portable storage medium (portable storage medium) such as M,
The data may be transferred from the portable storage medium to the main memory of the computer system or an external storage device. It is also possible to transfer the data from the computer 90 to the inside of the printer 20 and use it.
It is also possible to provide a device for providing this software program via a communication line and transfer the processing contents of the halftone module to this computer or printer 20 via the communication line for use. it can.

Next, a second embodiment of the present invention will be described. The printer 200 of the second embodiment has the same hardware configuration as the printer 20 of the first embodiment, and is different only in the processing in the halftone module 99 in the computer 90. That is, in the processing in the halftone module, when obtaining the recording ratio of the dark and light ink from the gradation data of the pixels of the original image, the relationship shown in FIG. In the example, the graph shown in FIG. 21 is referred to. That is, in this embodiment, as shown in FIGS. 21A and 21B, the recording rate of the light ink dots and the recording rate of the dark ink dots are set to those of the color currently processed by the halftone module 99. Not only the gradation data of the ink, for example, the cyan ink, but also the gradation data of the other color ink of the pixel of interest, here, the magenta ink gradation data. Specifically, regarding the cyan ink, when the amount of magenta ink to be ejected corresponding to the pixel of interest is large, the recording rate of the light cyan ink C2 of the cyan inks is lowered as a whole, The recording rate of the cyan ink C1 is increased accordingly. Similarly, as shown in FIGS. 22A and 22B, also for magenta ink, when the amount of cyan ink to be ejected corresponding to the pixel of interest is large, the magenta ink Light magenta ink M2
The recording rate of the whole is reduced, and the magenta ink M1
Is increasing the recording rate of.

In the embodiment described above, an image is recorded by using two kinds of inks having different dye densities as in the first embodiment, and in particular, a light dot formed by an ink having a low density (light cyan ink C2 in FIG. 14) is used. Ink of high density from the area below the gradation data at which the recording rate of
In No. 4, since the formation of the dark dot by the cyan ink C1) is started, the color mixing at the joint from the recording by the light dot to the recording by the dark dot is extremely smooth, and the printing quality is extremely high. In this embodiment, as the ink density of the other color for the same pixel is higher, the recording rate of the ink of lower density (C2 or M2) is reduced, and that amount is increased by the ink of higher density (C1 or M2).
Although it has been transferred to 1), since there is bleeding of ink of other colors, graininess is less noticeable than in the case of a single color.

Further, in this embodiment, as in the first embodiment,
The formation of dots by the dark ink is started from the area below the gradation data at which the recording rate of the light ink is the maximum, but in this embodiment, the generation limit of dots by the light ink is accelerated,
For light ink, do not generate dots forever,
The generation of dark ink dots is accelerated. Also in this case, the naturalness of the expression in the vicinity of the gradation where the high density ink and the low density ink start to mix is not impaired.

As a result, the recording rate of cyan ink or magenta ink recorded at the position corresponding to the pixel of interest is high when the recording rate of magenta ink or cyan ink recorded corresponding to the same pixel is high. Is a high density ink (C1 or C2).
Alternatively, since it is replaced with M1), it is possible to reduce the total amount of ink ejected per unit area without degrading the image quality. Therefore, it is possible to eject each color ink with a sufficient margin with respect to the limitation of the amount of ink that can be ejected per unit area (so-called ink duty) determined for each sheet. As a result, the paper does not swell with the ink or become unnatural due to the limitation of the ink duty.

In the second embodiment, for the pixel of interest, the density of cyan (gradation data), the density of magenta (gradation data), and the density of yellow necessary for expressing the hue of the pixel of interest. First find the density (gradation data), then
Next, although it has been described that the dot recording rate of the dark and light ink is determined based on these correlations, the dot recording rate of the dark and light ink of each color is directly obtained from the RGB data of the pixel of interest inside the print driver. It can also be one. That is, as shown in FIG. 23, a rasterizer 297, a color correction / halftone module 299, and a look-up table 300 are provided inside the print driver 296, and after the rasterizer 297 obtains RGB data in pixel units, the RGB data thereof is obtained. It is also possible to directly obtain the recording ratios of the dark and light inks for cyan and magenta and the recording ratios for the yellow ink by referring to the lookup table based on the data. 24A and 24B, the R of the pixel of interest is shown.
An example of a look-up table for directly obtaining the recording rate of cyan ink from GB data is shown.

In this configuration example, since the recording rate of each color ink can be directly obtained from the RGB data, there is an advantage that the configuration can be simplified. In the above-described second embodiment and its modified example, the higher the density of magenta (or cyan), the lower the recording rate of light ink dots for cyan (or magenta), and the darker ink recording rate. Although it is increased, it is also possible to make the recording rate of the dark and light ink different depending on the density of yellow. If the recording rates of the cyan, magenta, and yellow inks are not zero for the pixel of interest, the three colors are replaced with the black ink for printing, and according to the density of the black ink,
The recording rates of the light cyan ink C2 and the light magenta ink M2 are reduced, and the cyan ink C1 and the magenta ink M are reduced.
The recording rate of 1 may be increased.

In some of the embodiments described above, the recording rates of the light cyan ink C2 and the light magenta ink M2 are the magenta density at the position corresponding to the pixel of interest,
Although it is supposed to be lowered overall depending on the cyan density,
The relationship is not particularly limited to this. That is, the dot recording rate of the light ink and the dot recording rate of the dark ink can be freely determined according to the densities of the other inks at the positions corresponding to the pixel of interest. For example, when a plurality of inks are ejected so as not to meet the ink duty limit, when the recording rate of the light ink is lowered, or when the pixel in which cyan, magenta, and yellow are present is replaced with black, the dark ink is used. Can be reduced to temporarily increase the light ink to make the graininess of the joint less noticeable.

Further, in the above-described embodiment, the piezo element PE is used to eject the dark and light inks.
This is done by applying a voltage of a predetermined time width to E, but it is also easy to adopt another ink ejection method. Ink ejection methods that have been put into practical use are roughly classified into a method that separates and ejects ink particles from a continuous ink jet, and an on-demand method that is a method that is also adopted in the above-described embodiments. It For the former,
Known are a charge modulation method in which droplets are split from an ink jet by charge modulation, and a microdot method in which minute satellite particles generated when large-sized particles are split from the ink jet are used for printing. These methods can also be applied to the printing apparatus of the present invention that uses inks of a plurality of types of density.

In addition, the on-demand method generates ink particles when ink particles are required in dot units. In addition to the method using the piezo element adopted in the above-described embodiment, FIG. As shown in A) to (E), a method is known in which a heating element HT is provided in the vicinity of the ink nozzle NZ, a bubble BU is generated by heating the ink, and the pressure causes the ink particles IQ to be ejected. There is. These on-demand ink ejection methods can also be applied to the printing apparatus of the present invention that uses inks of a plurality of different densities.

[Brief description of drawings]

FIG. 1 is a schematic configuration of a printing apparatus 10 according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a printer 20 used in the embodiment.

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

FIG. 4 is a perspective view showing a configuration of a carriage 30.

FIG. 5 is an explanatory diagram showing an arrangement of heads 61 to 66 of respective colors in the print head 28.

6 is a perspective view showing the shape of a color ink cartridge 70. FIG.

FIG. 7 is an explanatory diagram showing a configuration for ejecting ink in each color head 61 to 66.

FIG. 8 is an explanatory diagram showing a state in which ink particles Ip are ejected due to expansion of the piezo element PE.

FIG. 9 is a block diagram illustrating a state of processing from image information handled by the computer 90 to printing.

FIG. 10 is an explanatory diagram showing components of each color ink.

FIG. 11 is a graph illustrating the relationship between the recording rate and the lightness of each color ink.

FIG. 12 is a flowchart illustrating a process in the halftone module 99.

FIG. 13 is a flowchart showing a dark dot formation determination processing routine.

FIG. 14 is a graph exemplifying the relationship between the recording rate and the gradation data for the light ink and the dark ink in the present embodiment.

FIG. 15 is an explanatory diagram showing an example of a threshold matrix of distributed dither for determining ON / OFF of dark dots.

FIG. 16 is an explanatory diagram showing an example of weighting for each pixel in which error is diffused in error diffusion.

FIG. 17 is a flowchart showing a light dot formation determination processing routine.

FIG. 18 is an explanatory diagram illustrating an example of how dots are formed by the light ink C2 and dots by the dark ink C1 in the present embodiment.

FIG. 19 is a graph showing another example of the relationship between the recording rate and the gradation data for light ink and dark ink.

FIG. 20 is a graph showing still another example of the relationship between the recording rate and the gradation data for the light ink and the dark ink.

FIG. 21 is a graph for obtaining the recording rate of cyan ink in the second embodiment.

FIG. 22 is a graph for obtaining the recording rate of magenta ink in the second embodiment.

FIG. 23 is a block diagram showing a modified example of the printer driver 296.

FIG. 24 is an explanatory diagram showing a look-up table for directly obtaining the recording rate of each color ink from RGB data.

FIG. 25 is an explanatory diagram showing another configuration example of the ink particle ejection mechanism.

[Explanation of symbols]

20 ... Printer 22 ... Paper feed motor 24 ... Carriage motor 25 ... Diethylene glycol 26 ... Platen 28 ... Print head 30 ... Carriage 31 ... Partition plate 32 ... Operation panel 34 ... Sliding shaft 36 ... Drive belt 38 ... pulley 39 ... Position detection sensor 40 ... Control circuit 41 ... CPU 43 ... ROM 44 ... RAM 50 ... I / F dedicated circuit 52 ... Head drive circuit 54 ... Motor drive circuit 56 ... Connector 61 to 66 ... Ink ejection head 68 ... Ink passage 70 ... Cartridge for color ink 71 ... Introduction tube 90 ... Computer 91 ... Video driver 93 ... CRT display 95 ... Application program 96 ... Printer driver 97 ... rasterizer 98 ... Color correction module 99 ... Halftone module P ... Paper PE ... Piezo element n ... nozzle

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[Procedure amendment]

[Submission date] November 18, 2002 (2002.11.
18)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Title of invention

[Correction method] Change

[Correction content]

Title of invention Ink cartridge

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction content]

[0001]

BACKGROUND OF THE INVENTION The present invention uses dark and light inks.
It was about the ink cartridge used in the printing apparatus.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

In a printer that represents an image by the presence or absence of dots (also referred to as dot on / off), dots are sparsely formed in a region having a low image density, that is, a region having a low dot density to be printed. Because of the granularity, the dots are noticeable. Therefore, a printing apparatus and a printing method using dark and light inks have been proposed for the purpose of further improving the printing quality. This aims to realize printing with excellent gradation expression by preparing high density ink and low density ink for the same color and controlling the ejection of both inks (see Patent Document 1 below).
See). In this document 1, a head for forming two types of dots of different shades for the same color is provided, and the number of shade dots formed in a predetermined dot matrix and their overlap are controlled according to the density information of the input image. Thus, a recording method and apparatus for recording a multi-gradation image are disclosed.

[Patent Document 1] Japanese Patent Laid-Open No. 61-108254

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006]

In order to achieve at least one of the above-mentioned objects, the first ink cartridge of the present invention comprises two types of light and shade of different densities.
A head capable of ejecting each of the above inks is provided and
Multi-gradation image by the distribution of two or more light ink dots
An ink cartridge used in a printing device capable of recording an image.
And a color image of two or more shades of different density.
Be stored in a container separate from the black ink.
Two or more types of color inks for light and shade are
The relationship between the gradation signal and the recording density depends on the ink on the low density side.
Therefore, the recording density of dots becomes maximum at a given gradation signal.
Is defined as a monotonically increasing relationship,
The gradation signal that maximizes the dot recording density of the ink
The gray level signal is lower than that of the No.
Is a characteristic that a dot appears,
Two or more types of intensities obtained based on the characteristics
The ink is ejected from the head according to the recording density of each dot
Supply two or more kinds of dark and light ink. As a result, the book
If the first ink cartridge of the invention is used, the dots of the ink of the high density side start to be mixed even before the recording density of the dots of the ink of the low density side reaches the maximum value, and a smoother gradation expression is realized. Ink supply to achieve
You can

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

The second ink cartridge of the present invention
Discharges two or more types of ink with different densities.
Equipped with a printable head, the density of two or more types of ink
Printing device that can record multi-gradation images according to the dot distribution
An ink cartridge used, comprising:
Tridge has two or more shades with the same hue but different densities.
The upper inks are arranged at positions adjacent to each other.
Two or more types of color inks for light and shade are
The relationship between the gradation signal and the recording density depends on the ink on the low density side.
Therefore, the recording density of dots becomes maximum at a given gradation signal.
Is defined as a monotonically increasing relationship,
The gradation signal that maximizes the dot recording density of the ink
The tone signal higher than the
The recording density of the image is sharply reduced.
The gradation 2 obtained from the gradation signal based on the characteristics
According to the recording density of each dot of more than one kind of ink,
Supply two or more kinds of light and shade ink ejected from the head
It As a result, when the recording density of the low-density ink dots exceeds the maximum value and the high-density ink dots start to mix, the low-density ink dot recording density drops sharply. , to achieve a more smooth gradation expression
Ink supply for can be realized .

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Delete

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0010

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[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0011

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[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Delete

[Procedure Amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0014

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[Procedure Amendment 12]

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[Name of item to be corrected] 0015

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[Procedure Amendment 13]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

As described aboveOf the present inventionink cartridgeso
Is a color ink of two or more types of dark and light with different densities.
Store in a separate container from the inkTheFrom that, the exchange
The replacement time is used for printing mainly on normal characters
Do not be affected by the exhaustion of black ink and the time to replace it.
Yes.

[Procedure Amendment 14]

[Document name to be amended] Statement

[Correction target item name] 0018

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[Procedure Amendment 15]

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[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described based on examples. As shown in FIG. 1, a printer 10 using an ink cartridge according to an embodiment of the present invention.
Is a computer 90 and a printer 20 connected to it.
It consists of and. The scanner 90 is further connected to the computer 90, and by loading and executing a predetermined program on the computer 90,
It functions as a printing device 10 having an image reading function as a whole. As shown, this computer 90
Is mainly the CPU 81 that executes various arithmetic processes for controlling the operations related to image processing according to the program,
The following units are connected to each other by a bus 80. R
The OM 82 stores in advance programs and data necessary for the CPU 81 to execute various arithmetic processes, and a RAM.
Reference numeral 83 is a memory in which various programs and data necessary for the CPU 81 to execute various arithmetic processes are temporarily read and written. The input interface 84 controls the input of signals from the scanner 12 and the keyboard 14, and the output interface 85 controls the output of data to the printer 20. The CRTC86 is a CRT2 capable of color display.
1 to control the signal output to the disk controller (DD
C) 87 controls data exchange with the hard disk 16, the flexible drive 15, or a CD-ROM drive (not shown). In the hard disk 16,
Various programs loaded in the RAM 83 and executed, various programs provided in the form of a device driver, and the like are stored. In addition, a serial input / output interface (SIO) 88 is connected to the bus 80. This SIO88 is connected to the modem 18,
It is connected to the public telephone line PNT via the modem 48. The computer 90 is connected to an external network via the SIO 88 and the modem 18, and by connecting to a specific server SV, it is possible to download the program necessary for image processing to the hard disk 76. It is also possible to load a necessary program on the flexible disk FD or a CD-ROM and have the computer 90 execute the program.

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Next, a second embodiment of the present invention will be described. The printer 200 using the ink cartridge of the second embodiment has the same hardware configuration as the printer 20 described in the first embodiment , and only the processing in the halftone module 99 in the computer 90 is performed. different. That is, of the processing in the halftone module,
When obtaining the recording ratio of the dark and light ink from the gradation data of the pixels of the original image, the relationship shown in FIG. 14 was referred to in the first embodiment, whereas the graph shown in FIG. 21 was referred to in the present embodiment. To do. That is, in this embodiment, as shown in FIG.
As shown in (A) and (B), the recording rate of the light ink dots and the recording rate of the dark ink dots are compared with the gradation data of the color ink currently processed by the halftone module 99, for example, cyan ink. Not only this, but it also depends on the gradation data of the other color ink of the pixel of interest, here magenta ink. Specifically, regarding the cyan ink, when the amount of magenta ink to be ejected corresponding to the pixel of interest is large, the recording rate of the light cyan ink C2 of the cyan inks is lowered as a whole, The recording rate of the cyan ink C1 is increased accordingly. Similarly, as shown in FIGS. 22A and 22B, also for magenta ink, when the amount of cyan ink to be ejected corresponding to the pixel of interest is large, the magenta ink The recording rate of the light magenta ink M2 is reduced as a whole, and the recording rate of the magenta ink M1 is increased accordingly.

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Further, in the above-described embodiment, the piezo element PE is used to eject the dark and light inks.
This is done by applying a voltage of a predetermined time width to E, but it is also easy to adopt another ink ejection method. Ink ejection methods that have been put into practical use are roughly classified into a method that separates and ejects ink particles from a continuous ink jet, and an on-demand method that is a method that is also adopted in the above-described embodiments. It For the former,
Known are a charge modulation method in which droplets are split from an ink jet by charge modulation, and a microdot method in which minute satellite particles generated when large-sized particles are split from the ink jet are used for printing. These methods also use the cartridge of the present invention that uses inks of multiple types of density .
It is feasible .

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In addition, the on-demand method generates ink particles when ink particles are required in dot units. In addition to the method using the piezo element adopted in the above-described embodiment, FIG. As shown in A) to (E), a method is known in which a heating element HT is provided in the vicinity of the ink nozzle NZ, a bubble BU is generated by heating the ink, and the pressure causes the ink particles IQ to be ejected. There is. These on-demand ink ejection methods also use the cartridges of the present invention that use inks of a plurality of different densities.
Can be realized by using .

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FIG. 1 includes an ink cartridge according to a first embodiment of the present invention.
2 is a schematic configuration of the printing device 10 that has been described.

Front page continued (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04N 1/23 101 F term (reference) 2C056 EA04 EB58 EB59 EC79 ED07 KC01 2C057 AF39 BA04 BA14 CA07 5C074 AA05 BB16 DD01 DD03 DD16 DD24 EE04 EE12 FF15 GG09

Claims (33)

[Claims] 1. A printing apparatus comprising heads capable of ejecting two or more types of inks of different densities having different densities, and capable of recording a multi-gradation image by a dot distribution of the inks of two or more types of density. Characteristic that dots with high-density ink appear with an input unit that inputs the gradation signal of the image to be printed and a gradation signal that is lower than the gradation signal that maximizes the recording density of dots with low-density ink Based on the input gradation signal, the recording density of each dot of the two or more types of dark and light ink is obtained, and the ejection of the ink from the head is controlled to determine the dot density of the two or more types of ink. A printing apparatus using dark and light ink, which includes a dot generation unit that performs gradation expression depending on the presence or absence. 2. A printing apparatus comprising heads capable of ejecting two or more types of inks having different densities and having different densities, and capable of recording a multi-gradation image by the distribution of dots of the inks of two or more types of density. With the input means for inputting the gradation signal of the image to be printed and the gradation signal having a higher dot recording density with the low density ink, the dot recording density with the low density ink is Based on the characteristics of sharp reduction,
The recording density of each dot of the two or more kinds of dark and light ink is obtained from the input gradation signal, the ejection of the ink from the head is controlled, and the gradation is determined by the presence or absence of the dots of the two or more kinds of dark and light ink. A printing device using dark and light ink, which is provided with a dot generating means for expressing. 3. A printing apparatus using the dark and light ink according to claim 1 or 2, wherein the dot generation means records each dot of the two or more kinds of dark and light ink from the input gradation signal. A printing device using a dark and light ink having a table giving density. 4. The dark and light ink is composed of two types of ink,
The printing apparatus using the dark and light ink according to claim 1 or 2, wherein the dye density of the low density ink is approximately ¼ of the dye density of the high density ink. 5. The head is a head capable of ejecting two or more kinds of dark and light inks for a plurality of inks having different hues, and the dot generating means is configured to perform the above-mentioned operation for each of at least two kinds of inks having different hues. The printing apparatus using the dark and light ink according to claim 1 or 2, further comprising dot generators of respective colors for performing a process of obtaining a recording density of each dot. 6. The printing apparatus according to claim 5, wherein the plurality of inks having different hues include cyan and magenta inks, and each color dot generation unit is a unit that performs the process for cyan and magenta. Printing device. 7. The printing apparatus according to claim 5, wherein each color dot generation unit determines the recording density of the dot in association with the data of ink of another hue ejected to the corresponding pixel. 8. The dot forming means for each color comprises a correcting means for correcting the dot recording density of the low density ink to be lower as the density of another hue ink ejected to the corresponding pixel is higher. Printing device. 9. The printing apparatus according to claim 5, wherein each color dot generation unit directly obtains a recording rate of dark and light dots for a plurality of inks having different hues from the hue data of the original image. A printing device having. 10. The head is provided with a mechanism for ejecting ink particles by a pressure applied to the ink by applying a voltage to an electrostrictive element provided in an ink passage.
A printing device using the dark and light ink according to claim 2. 11. The head according to claim 1, further comprising a mechanism for ejecting ink particles by a pressure applied to ink in the ink passage by bubbles generated by energizing a heating element provided in the ink passage. A printing apparatus using the dark and light ink according to Item 2. 12. The head is provided with a plurality of nozzles for ejecting the ink particles for each ink of each color and each density, which are arranged in a conveying direction of a paper to be printed.
0 or the printing device according to claim 11. 13. An ink cartridge used in the printing apparatus according to claim 1 or 2, wherein two or more kinds of color inks having different densities are stored in a container separate from black ink. Ink cartridge. 14. An ink cartridge used in the printing apparatus according to claim 1 or 2, wherein two or more kinds of dark and light ink having the same hue but different densities are arranged at positions adjacent to each other. ink cartridge. 15. The ink cartridge according to claim 14, wherein the two or more types of ink having different densities are different in density.
An ink cartridge which is a cyan ink, an ink having a dye concentration lower than that of the cyan ink, a magenta ink, an ink having a dye concentration lower than that of the magenta ink, and a yellow ink in order from one end. 16. A printing apparatus for printing by controlling the distribution density of dots formed by inks of different hues, capable of ejecting a plurality of inks of different hues, and at least one of the plurality of inks. One of them is a head capable of ejecting two or more kinds of dark and light inks, an input unit for inputting a gradation signal of an image to be printed, and a plurality of inks having different hues based on the input gradation signal. The dot for determining the dot density is obtained by ascertaining the recording density of each dot, and for the light ink of the two or more types of dark and light inks, is associated with the density of ink of another hue ejected to the corresponding pixel. A frequency determining unit and the ejection of ink from the head are controlled to record a plurality of inks having different hues and dots of two or more kinds of the light and shade on the recording medium. Printing apparatus comprising a dot recording means. 17. The dot frequency determining means uses, as the association, such a relationship that the higher the density of another hue ink ejected to the corresponding pixel, the lower the recording density of dots of the low density ink. 17. The printing apparatus according to claim 16, further comprising a correction unit that corrects the recording density of dots formed by the low density ink. 18. The printing apparatus according to claim 16, wherein the dot frequency determining unit directly obtains a recording rate of dark and light dots for a plurality of inks having different hues from the hue data of the original image. A printing device having. 19. The mechanism according to claim 1, wherein the head includes a mechanism for ejecting ink particles by a pressure applied to the ink by applying a voltage to an electrostrictive element provided in the ink passage.
A printing device using the dark and light ink according to item 6. 20. The mechanism according to claim 16, wherein the head is provided with a mechanism for ejecting ink particles by a pressure applied to the ink in the ink passage by bubbles generated by energizing a heating element provided in the ink passage. A printing device that uses dark and light inks. 21. A plurality of nozzles for ejecting the ink particles are arranged in the head for each ink of each color and each density along a conveying direction of a paper to be printed.
9. The printing device according to item 9. 22. The head is provided with a plurality of nozzles for ejecting the ink particles for each ink of each color and each density, which are arranged in a conveying direction of a paper to be printed.
No. 0 printing device. 23. An ink used in a printing apparatus, which comprises heads capable of ejecting two or more types of ink having different densities of different densities and is capable of recording a multi-gradation image by the dot distribution of the ink of two or more types of density. The cartridge is a cartridge, wherein the input device is based on a characteristic that dots of high density ink appear with a gradation signal lower than a gradation signal that maximizes the recording density of dots of low density ink. The recording density of each dot of the two or more kinds of dark and light ink is obtained from the gradation signal, and the ejection of the ink from the head is controlled to express the gradation by the presence or absence of the dots of the two or more kinds of ink of the dark and light. The amount of ink ejected from the ink cartridge is controlled so as to be performed. Ink cartridge comprising housed in a container separate from the ink. 24. The ink cartridge according to claim 23, wherein two or more kinds of dark and light inks having the same hue but different densities are arranged adjacent to each other. 25. The ink cartridge according to claim 24, wherein the two or more types of ink having different densities are different in density.
An ink cartridge which is a cyan ink, an ink having a dye concentration lower than that of the cyan ink, a magenta ink, an ink having a dye concentration lower than that of the magenta ink, and a yellow ink in order from one end. 26. Ink for use in a printing apparatus, comprising heads capable of ejecting two or more types of inks having different densities and having different densities, and capable of recording a multi-gradation image by the dot distribution of the two or more types of inks A cartridge, wherein the printing device has a characteristic that the recording density of dots of low-density ink is sharply reduced by a gradation signal higher than the gradation signal of maximum recording density of dots of low-density ink. Based on the input gradation signal, the recording density of each dot of the two or more types of dark and light ink is obtained, and the ejection of ink from the head is controlled to determine the presence or absence of dots of the two or more types of ink. The amount of ink ejected from the ink cartridge is controlled so that the gradation expression is performed by using the ink cartridge. Ink cartridge over the ink species, formed by arranged at positions adjacent to each other. 27. The ink cartridge according to claim 26, wherein the two or more types of ink having different densities have different concentrations.
An ink cartridge which is a cyan ink, an ink having a dye concentration lower than that of the cyan ink, a magenta ink, an ink having a dye concentration lower than that of the magenta ink, and a yellow ink in order from one end. 28. A head capable of respectively ejecting two or more types of ink having different densities and having different densities, and controlling the distribution of dots of the two or more types of ink, based on a gradation signal of an image to be printed. This is a method of printing multi-tone images, and the characteristic that dots of high-density ink appear from the range of tone signals that are lower than the tone signal that maximizes the recording density of dots of low-density ink. And inputting the gradation signal of the image to be printed, and determining the presence or absence of the dots of the two or more kinds of the light and shade inks from the input gradation signal in accordance with the stored characteristics. An image recording method using dark and light ink, which controls the ejection of ink from the head according to the presence or absence of dots, and performs gradation expression by the presence or absence of dots of the two or more types of dark and light ink. 29. A head capable of ejecting two or more types of ink having different densities and different densities, respectively, and controlling the distribution of dots of the two or more types of ink, based on the gradation signal of the image to be printed. A method of recording a multi-gradation image, in which the dot recording density of the low-density ink is steep when the gradation signal is higher than the gradation signal at which the dot density of the low-density ink is maximum. A characteristic to be reduced is stored, a gradation signal of an image to be printed is input, and the presence or absence of each dot of the two or more types of dark and light ink is determined from the input gradation signal according to the stored characteristic. An image recording method using dark and light ink, which controls the ejection of ink from the head in accordance with the presence or absence of a determined dot, and performs gradation expression by the presence or absence of dots of the two or more types of dark and light ink. 30. An image recording method for recording an image by controlling the distribution density of dots formed by inks of different hues, wherein a plurality of inks of different hues can be ejected. For at least one of them, a head capable of ejecting two or more kinds of dark and light inks is used, a gradation signal of an image to be printed is input, and a plurality of different hues are input based on the input gradation signal. The recording density of each dot of the ink is obtained, and the density of the dot is determined in association with the density of the ink of another hue ejected to the corresponding pixel for the light ink of the two or more kinds of dark and light ink. A dark / light ink is used which controls ejection of ink from the head to record a plurality of inks of different hues and dots of two or more kinds of dark and light inks on a recording medium. Image recording method. 31. A head capable of respectively ejecting two or more types of ink having different densities and having different densities is driven, and the distribution of dots of the two or more types of ink having different densities is controlled based on a gradation signal of an image to be printed. A recording medium in which at least a part of a program for forming a multi-gradation image is recorded so that it can be read by a computer, and the recording density of dots of low-density ink is lower than the maximum gradation signal. A table storing characteristics of dots of high density ink appearing in the range of gradation signals, a first program for inputting gradation signals of an image to be printed, and the input floor according to the stored characteristics. A recording medium for recording a second program for determining the presence or absence of each of the two or more types of dots of the light and shade based on the control signal. 32. A head capable of ejecting two or more types of ink having different densities of different densities is driven, and the distribution of dots of the two or more types of ink of different densities is controlled based on the gradation signal of the image to be printed. A recording medium in which at least a part of a program for forming a multi-gradation image is recorded in a computer-readable manner, and the recording density of dots of low-density ink is higher than the gradation signal at which the maximum value is obtained. With respect to the gradation signal, a table storing characteristics that the recording density of dots of low-density ink sharply decreases, a first program that inputs the gradation signal of the image to be printed, A recording medium on which is recorded a second program for determining the presence or absence of each of the two or more types of dots of the light and shade ink from the input gradation signal. 33. A plurality of inks having different hues can be ejected, and for at least one of the plurality of inks, a head capable of ejecting two or more kinds of dark and light inks is driven, and the inks having the different hues are ejected. Is a recording medium in which at least a part of a program for recording an image by controlling the distribution density of dots formed by the computer is recorded so that it can be read by a computer, and a first gradation signal of an image to be printed is input. The recording density of each dot of a plurality of inks having different hues is obtained based on the program and the input gradation signal, and the light ink of the two or more kinds of dark and light ink is ejected to the corresponding pixel. In accordance with the second program for determining the density of dots in relation to the densities of inks of other hues to be recorded and the density of each dot thus determined, Third program means and recording medium recording for outputting a signal for controlling the de.