JP3981480B2 - Printing apparatus and recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printing apparatus that prints a multicolor image by a head that includes a plurality of dot forming elements for forming dots for each color, and a recording medium that records a program for generating data supplied to the printing apparatus. .
[0002]
[Prior art]
As an output device of a computer, an ink jet printer that records an image by forming dots with several colors of ink ejected from a plurality of nozzles provided in a head is used to output an image processed by a computer or the like in multiple colors and multiple gradations. Widely used for printing. In such a printer, normally, only two gradations expressed by dot on / off can be used for each pixel, and therefore the gradation of the original image data is expressed by the dispersibility of the dots.
[0003]
In recent years, there has been a tendency for printers to have high image quality. High image quality is achieved by increasing the printing resolution of the printer. That is, by increasing the resolution and reducing the dots formed in each pixel, it is possible to reduce the visibility of the dots and print an image with a smooth grainy feeling. High image quality is realized by enriching the gradation expression for each pixel. In order to enrich the gradation expression for each pixel, a printer having dark and light inks for some hues has been proposed. According to such a printer, by using different shades of ink, it is possible to realize a very smooth gradation expression and improve the image quality.
[0004]
While high image quality is achieved in this way, there is a high demand for an improvement in printing speed. In order to improve the printing speed in an ink jet printer, a multihead having a large number of nozzles for ejecting ink for each color is generally used. In recent years, as the resolution of printers has increased, in order to ensure a sufficient printing speed, a larger number of nozzles have been provided and the size of the head tends to increase. Further, as described above, in printers using dark and light inks, the heads tend to become larger due to the increase in the types of ink.
[0005]
[Problems to be solved by the invention]
However, by increasing the size of the head, high-speed printing can be realized, but various problems have occurred. For example, in an inkjet printer, printing is performed while performing main scanning that reciprocates the head. However, vibration and noise during main scanning have become intense due to the increase in size of the head. As a matter of course, the power required for main scanning of such a large-sized head has also increased. Further, the increase in the size of the head has been a factor in improving the manufacturing cost of the head. In addition, the overall size of the printer has been increased.
[0006]
The present invention has been made to solve such problems, and an object of the present invention is to provide a printing apparatus that reduces vibrations and other harmful effects without extremely impairing image quality and printing speed, and a technique related to the printing apparatus.
[0007]
[Means for solving the problems and their functions and effects]
In order to solve at least a part of the above-described problems, the present invention employs the following configuration.
The printing apparatus of the present invention includes:
A printing apparatus for printing a multicolor image by forming dots according to image data on a print medium by a head provided with a plurality of dot forming elements for forming dots for each color,
The head isRegarding dot forming elements for forming chromatic dots,The gist of the invention is that the number of dot forming elements of a specific color having a small influence on image quality is smaller than the number of dot forming elements of other colors.
[0008]
According to such a printing apparatus, the number of dot forming elements provided in the entire head can be reduced by reducing the number of dot forming elements for some specific colors. Therefore, the head can be reduced in size, and various problems caused by the increase in the size of the head, such as vibration, noise, and manufacturing cost, can be eliminated.
[0009]
A specific color with a small number of dot forming elements has a smaller number of dots formed than other colors. As a result, it is not possible to realize printing with a gradation expression or resolution as high as that of other colors with a specific color. However, in this printing apparatus, the number of dot forming elements is reduced for some specific colors that have a small effect on image quality. Therefore, the influence on the image quality caused by reducing the number of dot forming elements is hardly visually recognized. As a result, this printing apparatus can reduce the size of the head without drastically degrading the image quality of the printed image.
[0010]
When printing an image by forming dots with a constant resolution for all the inks, other colors (hereinafter referred to as general colors) are provided with extra dot forming elements, taking a specific color as a reference. Such surplus dot forming elements can be used in various ways to improve image quality. For example, with respect to general colors, if dots are formed by overlapping a plurality of times for each pixel, the gradation expression for each pixel can be enriched.
[0011]
For general colors, printing may be performed by a so-called overlap method using surplus dot forming elements. The overlap method is a recording method in which each raster, that is, a dot row is formed by a plurality of dot forming elements. For example, when a raster is formed by two dot forming elements, odd-numbered dots of the raster are formed by the first dot forming element, and even-numbered dots are formed by the second dot forming element. . By forming a raster using a plurality of dot forming elements in this way, it is possible to disperse the dot forming position shift caused by mechanical manufacturing errors of the respective dot forming elements, and to reduce so-called banding. There is.
[0012]
According to the printing apparatus of the present invention, it is possible to realize the above-described rich gradation expression and overlap method recording without reducing the printing speed by effectively utilizing the excessive dot forming elements of general colors. Can do.
[0013]
In the printing apparatus of the present invention, an image may be printed at a different resolution for each color according to the number of dot forming elements.
For example, in the printing apparatus of the present invention,
For a pixel having a resolution set based on the number of dot formation elements for each color, multi-value conversion means for performing halftone processing based on the image data for each color, and driving the dot formation element according to the processing result Then, it may be provided with dot forming means for forming dots with the resolution set for each color.
[0014]
In such a printing apparatus, dots are formed with a resolution set based on the number of dot forming elements for each color. That is, dots are formed at a high resolution for a general color having a large number of dot formation elements, and dots are formed at a low resolution for a specific color having a small number of dot formation elements. By reducing the resolution of a specific color with a small number of dot forming elements, the number of dots to be formed with the specific color can be reduced, so that an image can be printed without decreasing the printing speed.
[0015]
Various elements can be applied as the aforementioned dot forming elements. For example, a so-called thermal transfer type dot forming element or a thermal sublimation type dot forming element may be applied. Further, an impact type dot forming element may be applied.
[0016]
The dot forming element may be a nozzle that ejects ink to form dots. Since the nozzle for ejecting ink has a relatively large dot forming element, the effectiveness of the present invention is high.
In this case, any method may be applied as a method for ejecting ink. For example, a method of ejecting ink using deformation of a piezo element when a voltage is applied can be applied. In addition, a method of discharging ink with the pressure of bubbles generated in the ink passage by heating the heater may be applied.
[0017]
In a printing apparatus including a nozzle that ejects ink,
It is preferable that an ink storage unit that stores ink of each color at a volume ratio corresponding to the number of dot forming elements is provided.
In general, the amount of ink consumed is proportional to the number of dots formed and is generally proportional to the number of dot forming elements. Therefore, if the ink storage unit described above is provided, the ink of each color can be consumed evenly, and the printing apparatus can be used economically.
[0018]
In the printing apparatus of the present invention, the specific color that has little influence on the image quality means a color that does not cause a significant deterioration in image quality even when the number of dot forming elements is reduced. As the specific color, various colors can be selected in accordance with the ratio of reducing the number of dot forming elements.
In general, ink with relatively high brightness often has a specific color.
When the head is a head capable of forming dots of at least three colors of cyan, magenta, and yellow,
The specific color may be yellow.
[0019]
Of course, the specific color is not limited to a light color. For example, among the colors provided in the head, a color that is less frequently used than other colors may be used as the specific color.
[0020]
The specific color need not be limited to a single color, and a plurality of colors may be used as the specific color. For example, in a printing apparatus provided with inks having different densities, low density inks or specific colors may be used in addition to yellow. Needless to say, when a plurality of colors are specified as described above, it is not necessary to match the number of dot forming elements between the specified colors.
[0021]
In a printing apparatus having a head capable of forming dots of at least three colors of cyan, magenta, and yellow,
The cyan, magenta, and yellow inks are desirably inks that are adjusted to a density ratio that allows the region to be visually recognized as black when dots are formed at a rate corresponding to the number of dot forming elements.
[0022]
If ink adjusted to such a density ratio is used, even if the number of yellow dot forming elements as a specific color is small, black can be appropriately expressed by mixing the three colors. Therefore, it is possible to reduce the number of dot formation elements of a specific color without impairing the black tone expression.
[0023]
In a printing apparatus provided with a nozzle for discharging ink as a dot forming element,
The head is a head including dot forming elements in a state where a plurality of predetermined unit patterns are arranged for each color for at least a part of the other colors.
Further, the ink cartridge storing ink of each color can be mounted in a replaceable manner, and a mounting section capable of supplying ink from the cartridge to each dot forming element for each unit pattern can be provided.
[0024]
In this way, since ink is supplied from the ink cartridge to each dot forming element for each unit pattern, the number of colors to be used can be changed by replacing the ink cartridge. For example, for four colors of cyan, magenta, yellow, and black, if two unit patterns each correspond to cyan, magenta, and black, the ink can be replaced by replacing the ink cartridge. It is also possible to supply cyan inks having different densities to one unit pattern. By making it possible to change the number of colors to be used in this way, it is possible to flexibly cope with the purpose of the user.
[0025]
In the case of adopting a configuration for supplying ink for each unit pattern in this way,
The unit pattern is preferably an arrangement of dot forming elements for the specific color.
[0026]
In this way, even when the number of colors to be used is changed, the image recording method can be set on the basis of the arrangement of the dot forming elements of a specific color, and the ink cartridges having different numbers of colors can be easily used.
[0027]
As a specific arrangement method,
A head drive unit that forms dots by performing main scanning that reciprocates the head in one direction and sub-scanning that drives the print medium relative to the head in a direction that intersects the direction of the main scanning;
The head is
The dot forming elements of the specific color are provided in a plurality of arrangements at a predetermined pitch in the sub-scanning direction,
The other color dot forming elements may be a head provided with an arrangement in which the dot forming elements of any one of the specific colors coincide with the positions in the sub-scanning direction.
[0028]
In this way, for general colors, dots can be recorded using a plurality of nozzles for each raster, and printing with excellent image quality can be realized. In addition, since the specific color and the other colors have the same position in the sub-scanning direction, there is an advantage that the feed amount for the sub-scanning can be easily set. Specifically, the general color can be arranged in a plurality of rows arranged in the main scanning direction with the nozzle arrangement of a specific color as one unit pattern. Further, the above-described arrangement may be realized by arranging a plurality of unit patterns in the sub-scanning direction.
[0029]
As other arrays,
A head drive unit that forms dots by performing main scanning that reciprocates the head in one direction and sub-scanning that drives the print medium relative to the head in a direction that intersects the direction of the main scanning;
The head is
The dot forming elements of the specific color are provided in a plurality of arrangements at a predetermined pitch in the sub-scanning direction,
For the other colors, the head is provided with dot forming elements in an arrangement in which the interval between adjacent dot forming elements in the sub-scanning direction is m equal to the pitch (m is an integer of 2 or more). Can do.
[0030]
When the general color has twice as many dot forming elements as the specific color, the dot forming elements of the other colors are arranged in a staggered manner. In this way, the distance between the dot forming elements in the sub-scanning direction can be made extremely small, so that the head can be further miniaturized. In addition, when an ink cartridge with an increased number of colors is attached to such a head, the dot forming elements on adjacent rows are misaligned in the sub-scanning direction, so that ink dots of different colors are on the same raster. Forming at very short intervals can be avoided, and bleeding can be avoided. The same effect can be obtained when there are three or more times the general color dot forming elements as compared with the specific color.
[0031]
Specifically, the dot formation elements of the general color are arranged in a plurality of columns in the main scanning direction while shifting the position of the unit pattern in the sub-scanning direction as a single unit pattern. Can do. Further, the above-described arrangement may be realized by arranging a plurality of unit patterns in the sub-scanning direction.
[0032]
In the printing apparatus in which the number of colors can be changed by replacing the ink cartridge in this way,
Furthermore, detection means for detecting the number of inks provided in the ink cartridge mounted on the mounting unit,
It is desirable to provide dot formation determination means for determining on / off of the dot by each ink for each pixel according to the detection result.
By so doing, it is possible to print an image by appropriately using ink according to the mounted ink cartridge.
[0033]
Also, a mechanism for avoiding color mixing with the previous color may be provided immediately after replacement with an ink cartridge having a different number of colors. Examples of such a mechanism include a unit that cleans the dot forming element when the ink cartridge is replaced with an ink cartridge having a different number of colors, and a unit that allows the ink cartridge and the dot forming element to be replaced together.
[0034]
The present invention can also be realized by various ink cartridge modes described below as a sub-combination of a printing apparatus in which an ink cartridge can be mounted in a replaceable manner.
That is, the first ink cartridge of the present invention is
In the ink cartridge, the same type of ink can be supplied to the plurality of unit patterns.
[0035]
The second ink cartridge of the present invention is
An ink cartridge capable of supplying different ink for each unit arrangement.
[0036]
The third ink cartridge of the present invention is
The ink cartridge stores at least a part of ink other than the color supplied with ink for each unit pattern separately from the color ink supplied with ink for each unit pattern.
[0037]
The fourth ink cartridge of the present invention is
For inks of colors that store at least cyan, magenta, and yellow inks and that are supplied with a small number of dot forming elements, use inks with a higher density than the density of the three color dot forming elements. This is an ink cartridge to be stored.
[0038]
The fifth ink cartridge of the present invention is
A density ratio at which at least cyan, magenta, and yellow ink are stored, and the three color inks can be visually recognized as black when the dots are formed at a ratio of the number of dot forming elements to which each ink is supplied. This is an ink cartridge which is the ink adjusted to.
[0039]
The sixth ink cartridge of the present invention is
The ink cartridge stores each ink in a volume corresponding to the ratio of the number of dot forming elements to which each ink is supplied.
[0040]
The seventh ink cartridge of the present invention is
An ink cartridge for use in a printing apparatus comprising a detecting means for detecting the number of inks provided in the ink cartridge mounted on the mounting unit,
The ink cartridge includes an identification mechanism corresponding to the number of inks in a state where the detection unit can detect the ink cartridge.
[0041]
When these ink cartridges are used in the above-described printing apparatus, the printing apparatus can be driven in a state where the various effects described above are produced.
In the printing apparatus that forms dots and prints a multicolor image, the head can be switched to a combination of the first and second colors and used as a configuration in which the problems to be solved are the same. It is good. Here, the first color combination includes the second color combination and has a large number of colors. Further, a dot forming element number that is a multiple of a predetermined unit number is assigned to each color, and a dot forming element of the unit number is assigned to at least a color included in the second color combination. By doing so, the head can be switched and used in a combination of a plurality of colors without increasing the size of the head.
In such a configuration, it is further desirable to assign a unit number of dot forming elements to a part of specific colors having a small influence on image quality among colors shared by the combination of the first and second colors. . By doing so, it is possible to further reduce the size.
The first color combination and the second color combination can take various forms. For example, the first color combination includes a multi-density hue having a plurality of colors having the same hue and different densities. In the second color combination, the number of colors included in the multi-density hue can be made smaller than that in the first color combination.
As a more specific configuration, for example, the second color combination is black, cyan, magenta, and yellow, and the first color combination includes a light color with low density for at least one of cyan and magenta. Can do. In such a configuration, it is preferable to assign a unit number of dot forming elements for light colors and yellow.
In the configuration including the head that can be switched to a plurality of colors as described above, it is detected whether the ink cartridge mounted on the head corresponds to the combination of the first color and the second color, and the head is correspondingly detected. It is desirable to switch the driving state. By doing so, it is possible to realize printing suitable for each color combination.
[0042]
The present invention can also be realized in the form of a recording medium on which a program for generating data to be supplied to a printer is recorded.
That is, the recording medium of the present invention is
For generating data to be supplied to a printer that prints a multicolor image by forming dots according to image data on a print medium by a head having different numbers of dot forming elements for forming dots for each color. A recording medium on which a program is recorded in a computer-readable manner,
A function of inputting the image data at a resolution set based on the number of dot forming elements for each color;
For each color, for a pixel configured with a resolution set based on the number of dot forming elements of the color, a function of performing halftone processing based on the image data;
It is a recording medium on which a program for realizing the function of outputting the halftone processed data is recorded.
[0043]
In such a recording medium,
Furthermore, the function of inputting the number of colors of ink supplied to the printer and the number of dot forming elements for each ink;
A program having a function of setting the resolution for each color based on the input number of ink colors and the number of dot forming elements may be recorded.
[0044]
When the data set by executing the program recorded on the recording medium is supplied to the printer, the above-described printing apparatus of the present invention can be realized. Storage media include flexible disks, CD-ROMs, magneto-optical disks, IC cards, ROM cartridges, punch cards, printed matter printed with codes such as bar codes, computer internal storage devices (memory such as RAM and ROM), and Various media that can be read by a computer, such as an external storage device, can be used. Moreover, the aspect as a program supply medium which supplies the program which implement | achieves said function to a computer via a communication path is also included.
[0045]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples.
(1) Device configuration:
FIG. 1 is a block diagram showing the configuration of a printing system to which a printing apparatus according to an embodiment of the present invention is applied. As shown in the figure, a scanner 12 and a color printer 22 are connected to a computer 90. A predetermined program is loaded and executed on the computer 90 to function as a printing apparatus. The computer 90 includes the following units connected to each other by a bus 80 with a CPU 81 that executes various arithmetic processes for controlling operations related to printing according to a program. The ROM 82 stores programs and data necessary for the CPU 81 to execute various arithmetic processes in advance, and the RAM 83 temporarily reads and writes various programs and data necessary for the CPU 81 to execute various arithmetic processes. Memory. The input interface 84 controls input of signals from the scanner 12 and the keyboard 14, and the output interface 85 controls output of data to the printer 22. The CRTC 86 controls signal output to the CRT 21 capable of color display, and the disk controller (DDC) 87 controls data exchange with the hard disk 16, the CD-ROM drive 15, or a flexible disk drive (not shown). The hard disk 16 stores various programs loaded in the RAM 83 and executed, various programs provided in the form of device drivers, and the like.
[0046]
In addition, a serial input / output interface (SIO) 88 is connected to the bus 80. The SIO 88 is connected to the modem 18 and is connected to the public telephone line PNT via the modem 18. The computer 90 is connected to an external network via the SIO 88 and the modem 18, and a program necessary for image printing can be downloaded to the hard disk 16 by connecting to a specific server SV. . It is also possible to load a necessary program from the flexible disk FD or CD-ROM and cause the computer 90 to execute it. Of course, these programs can adopt a mode in which the entire program necessary for printing is loaded together, or can be a mode in which only the characteristic part of the present embodiment is loaded as a module.
[0047]
FIG. 2 is a block diagram illustrating a software configuration of the printing system. In the computer 90, an application program 95 operates under a predetermined operating system. A video driver 91 and a printer driver 96 are incorporated in the operating system. An application program 95 that performs image retouching or the like reads an image from the scanner 12 and displays the image on the CRT display 21 via the video driver 91 while performing predetermined processing on the image. Data ORG supplied from the scanner 12 is original color image data ORG composed of three color components of red (R), green (G), and blue (B) read from a color original.
[0048]
When the application program 95 issues a print command, the printer driver 96 of the computer 90 receives image data from the application program 95, and a signal that can be processed by the printer 22 (multi-valued signal for each ink). Has been converted. In the example shown in FIG. 2, the printer driver 96 includes a color correction module 98, color correction tables LUT1 and LUT2, a resolution conversion module 97, a halftone module 99, a rasterizer 100, and a cartridge determination unit 101. Yes.
[0049]
The cartridge determination unit 101 determines the type of cartridge mounted on the printer 22. As will be described later, in this embodiment, two types of cartridges having different numbers of ink colors can be selectively mounted. The printer 22 is provided with a sensor for identifying the cartridge thus mounted. The cartridge determination unit 101 determines the type of the ink cartridge installed in the printer 22 based on the signal from this sensor. The determined result is transferred to the resolution conversion module 97, the color correction module 98, and the rasterizer 100. Each of these modules executes respective processes according to the type of the ink cartridge as shown below.
[0050]
The color correction module 98 converts the RGB color components of each pixel into ink data of each color used by the printer 22 by referring to the color correction tables LUT1 and LUT2. In this embodiment, the color-corrected data has 256 gradation values for each ink. Different ink cartridges use different types of ink. Therefore, in this embodiment, two types of color correction tables LUT1, LUT2 corresponding to each ink cartridge are prepared. The color correction module 98 performs color correction using different color correction tables to be referred to according to the type of ink cartridge.
[0051]
The resolution conversion module 97 converts the resolution of color image data, that is, the number of pixels per unit length, into a printing resolution. In this embodiment, printing is executed with different resolutions depending on the type of ink cartridge. The resolution conversion module 97 sets the print resolution corresponding to the ink cartridge based on the information from the cartridge determination unit 101, and generates data of the resolution. The resolution-converted image data is data having the density to be expressed by each ink used for printing in 256 gradations.
[0052]
The halftone module 99 executes halftone processing for expressing such gradation values by the printer 22 by forming dots dispersedly. The processed image data is rearranged in the order of data to be transferred to the printer 22 by the rasterizer 100, and output as final print data FNL. The order in which the data is rearranged depends on the print resolution. The rasterizer 100 changes the data arrangement based on the information from the cartridge determination unit 101 so that printing can be performed at a resolution corresponding to the type of the ink cartridge. In this embodiment, the printer 22 only plays the role of forming dots according to the print data FNL and does not perform the above-described image processing. However, it goes without saying that these processes may be performed by the printer 22.
[0053]
FIG. 3 shows a schematic configuration of the printer 22 applied to the present embodiment. As shown in the figure, the printer 22 includes a circuit for transporting the paper P by the paper feed motor 23, a circuit for reciprocating the carriage 31 in the axial direction of the platen 26 by the carriage motor 24, and a print head mounted on the carriage 31. And a control circuit 40 that controls the exchange of signals with the paper feed motor 23, the carriage motor 24, the print head 28, and the operation panel 32. .
[0054]
The circuit for reciprocating the carriage 31 in the axial direction of the platen 26 is an endless drive belt between the carriage motor 24 and a slide shaft 34 that is laid in parallel with the axis of the platen 26 and slidably holds the carriage 31. 36, a pulley 38 for extending 36, a position detection sensor 39 for detecting the origin position of the carriage 31, and the like.
[0055]
FIG. 4 is a perspective view of the carriage 31. As shown in the drawing, a black ink (K) ink cartridge 71 and a color ink cartridge 72A or 72B can be mounted on the carriage 31 of the printer 22. As the color ink cartridge, two types of cartridges having different ink colors can be selected and mounted. The first color ink cartridge 72A (hereinafter referred to as a four-color cartridge) is a cartridge that contains three colors of ink of cyan (C), magenta (M), and yellow (Y). The second color ink cartridge 72B (hereinafter referred to as a six-color cartridge) contains five colors of ink, cyan (C), light cyan (LC), magenta (M), light magenta (LM), and yellow (Y). Cartridge.
[0056]
FIG. 5 is a perspective view of the four-color cartridge 72A, and FIG. 6 is a perspective view of the six-color cartridge 72B. IC chips 79A and 79B for identifying the type are affixed to the ink cartridges 72A and 72B. Information on these IC chips is detected by a non-contact identification sensor 29 provided in the printer 22. The identification sensor 29 may be provided in the carriage 31 as shown in FIG. 3 or may be provided in the main body of the printer 22 to detect when the carriage 31 is in the retracted position. In this embodiment, the type of cartridge is detected using an IC chip, but other methods may be used. For example, a configuration in which a barcode is attached to the ink cartridge and the barcode can be read on the carriage 31 or the printer 22 side may be employed. In addition, a different number of holes may be formed in the ink cartridge according to the type, and a micro switch may be provided in the carriage 31 so that the number to be turned on changes according to the number of holes. Further, the number of holes and the number of inks may be detected by an optical sensor.
[0057]
An ink discharge head is formed on the print head 28 below the carriage 31. At the bottom of the carriage 31, introduction pipes 73 to 78 for guiding ink from the ink tank to the respective color heads are provided upright. The introduction pipe 73 is a pipe for guiding ink from the black ink cartridge 71. The introduction pipes 74 to 78 are pipes for guiding ink from the color ink cartridges 72A and 72B. The correspondence between the introduction tubes 73 to 78 and the inks of the respective colors is shown in FIGS. FIG. 5 is a perspective view showing the correspondence when the four-color cartridge 72A is mounted. As shown in the drawing, the introduction pipe 78 and yellow correspond, the introduction pipes 77 and 76 correspond to magenta, and the introduction pipes 75 and 74 correspond to cyan ink, respectively. FIG. 6 is a perspective view showing the correspondence when the six-color cartridge 72B is mounted. As shown in the drawing, the introduction pipe 78 and yellow, the introduction pipe 77 and light magenta, the introduction pipe 76 and magenta, the introduction pipe 75 and light cyan, and the introduction pipe 74 and cyan correspond, respectively.
[0058]
7 and 8 are explanatory views showing the arrangement of nozzles in the print head 28 and the corresponding relationship with each ink. 7 corresponds to the case where the four-color cartridge 72A is mounted, and FIG. 8 corresponds to the case where the six-color cartridge 72B is mounted. When the four-color cartridge 72A is mounted, the nozzle arrangement is composed of four sets of nozzle arrays that eject ink for each color, as shown in FIG. For the nozzles of black, cyan, and magenta, 48 nozzles are arranged in a staggered manner, and the interval between adjacent nozzles in the sub-scanning direction is k1. In the yellow nozzle, 24 nozzles that are halves of other colors are arranged in a line, and the interval in the sub-scanning direction is an interval k2 that is twice k1. For cyan, magenta, and yellow color inks, ink is supplied from the introduction tube from the ink cartridge 72A in units of rows aligned in the sub-scanning direction. That is, ink is supplied from the introduction pipes 76 and 77 to the two nozzle arrays that discharge magenta. Ink is supplied from the introduction tubes 74 and 75 to the two nozzle rows that discharge cyan.
[0059]
When the six-color cartridge 72B is mounted, the nozzle arrangement is composed of six sets of nozzle arrays that eject ink for each color, as shown in FIG. For black, there is no difference from the case where the four-color cartridge 72A is mounted. For color ink, 24 nozzles are arranged in a staggered pattern for each of cyan, light cyan, magenta, light magenta, and yellow. The interval between the nozzles adjacent to each other in the sub-scanning direction is an interval k2 that is twice as long as k1. As for color ink, ink is supplied from the introduction tube for each color in units of rows arranged in the sub-scanning direction from the ink cartridge 72B.
[0060]
The printer 22 is configured to supply color ink for each nozzle row in this way, so that ink having a different number of colors can be supplied to the print head 28 by replacing the ink cartridge. On the other hand, since black always uses the same type of ink, it has a simple configuration for supplying ink in units of two nozzle rows. Further, by configuring the black ink cartridge 71 separately from the color ink cartridges 72A and 72B, only the color ink cartridges 72A and 72B can be replaced independently, thereby improving the convenience of the user. Yes.
[0061]
The configuration of the two types of ink cartridges 72A and 72B in this embodiment will be described. When the four-color cartridge 72A is mounted, the number of yellow nozzles is half that of the other colors, as shown in FIG. In this embodiment, as will be described later, printing is executed with different resolutions for each ink according to the number of nozzles. Therefore, when printing is performed with the four-color cartridge 72A mounted, the number of yellow dots is reduced compared to other colors. Although the number of dots of each color varies depending on the image to be printed, it is considered that the average is proportional to the number of nozzles. Therefore, the number of yellow dots is about half that of other colors. In consideration of this point, the four-color cartridge 72A has the yellow ink capacity approximately half that of the other colors. In contrast, in the six-color cartridge 72B, the number of nozzles corresponding to the five colors is the same. Accordingly, the ink capacities of the respective colors are made almost equal. By doing so, ink of each color can be used evenly, and waste during printing can be suppressed.
[0062]
On the other hand, the relationship of ink density is reversed. FIG. 9 is a graph showing the relationship between the recording rate and brightness of dots formed with each ink. The value of brightness varies depending on the density of each ink. The density of each ink can be set to any value independently, but when three colors of cyan, magenta, and yellow are formed at the same ratio,Color mixingIt is desirable to adjust the density so that black (hereinafter referred to as composite black) is expressed. In this way, smooth gradation expression can be realized for black by properly using black ink and composite black.
[0063]
The ink cartridges 72A and 72B of the present embodiment are also adjusted to a density capable of expressing composite black. As described above, since the ink cartridge 72B has the same number of cyan, magenta, and yellow nozzles, the density is adjusted so that composite black can be expressed when approximately the same number of dots are recorded. The brightness when dots are recorded at such a density is a graph indicated by C, M, Y2 in FIG.
[0064]
On the other hand, the ink cartridge 72A has few yellow nozzles. Therefore, each ink is adjusted to a density that can represent composite black when yellow dots are formed at a recording rate of about half that of cyan and magenta. That is, as shown in FIG. 9, when the yellow of the four-color cartridge 72A is recorded at a recording rate of about 50%, the brightness expressed when the yellow of the six-color cartridge 72B is recorded at the recording rate of 100%. The yellow ink density is set to be equal. As a result, the yellow ink density of the four-color cartridge 72A is higher than the yellow ink density of the six-color cartridge 72B. However, the brightness expressed when the dots are formed is not necessarily proportional to the concentration of the dye contained in the ink. Therefore, the yellow dye density of the four-color cartridge 72A is not always double the yellow dye density of the six-color cartridge 72B.
[0065]
The ink ejection principle of the printer 22 will be described. FIG. 10A is an explanatory diagram showing a schematic configuration inside the ink ejection head 28. For the sake of illustration, the portions for ejecting black ink (K), cyan (C), and magenta (M) are shown. When the ink cartridges 71 and 72A are mounted on the carriage 31, the ink of each color is supplied to the print head 28 through the ink passage 68 shown in FIG.
[0066]
In the print head 28, a piezo element PE is arranged for each nozzle as shown in FIG. As is well known, the piezo element PE is an element that transforms electro-mechanical energy at a very high speed because the crystal structure is distorted by application of a voltage. In this embodiment, by applying a voltage having a predetermined time width between the electrodes provided at both ends of the piezo element PE, the piezo element PE expands by the voltage application time, as shown by an arrow in FIG. Then, one side wall of the ink passage 68 is deformed. As a result, the volume of the ink passage 68 contracts according to the expansion of the piezo element PE, and the ink corresponding to the contraction becomes particles Ip and is ejected from the tip of the nozzle Nz at high speed. Printing is performed by the ink particles Ip soaking into the paper P mounted on the platen 26.
[0067]
Next, the internal configuration of the control circuit 40 will be described. FIG. 11 is an explanatory diagram showing the internal configuration of the control circuit 40. As shown in the figure, the control circuit 40 includes a CPU 41, a PROM 42, a RAM 43, a PC interface 44 for exchanging data with the computer 90, a paper feed motor 23, a carriage motor 24, an identification sensor 29, and an operation panel. A peripheral input / output unit (PIO) 45 for exchanging signals with 32, a timer 46 for timing, a drive buffer 47 for outputting dot on / off signals to the print head 28, and the like are provided. These elements and circuits are connected to each other via a bus 48. The control circuit 40 also includes a transmitter 51 that outputs a drive waveform for driving the piezoelectric element PE of each nozzle at a predetermined frequency, and a distribution output device 55 that distributes the output from the transmitter 51 to the print head 28. Is provided.
[0068]
The control circuit 40 receives the dot data processed by the computer 90, temporarily stores it in the RAM 43, and outputs it to the driving buffer 47 at a predetermined timing. From the drive buffer 47, data indicating dot on / off for each nozzle is output to the distribution output unit 55. As a result, a drive waveform for driving the piezo element PE is output to the nozzle to form a dot, and a dot is formed.
[0069]
The printer 22 having the hardware configuration described above transports the paper P by the paper feed motor 23, reciprocates the carriage 31 by the carriage motor 24, and simultaneously drives the piezo elements PE of the print head 28 so that each color ink And forming dots to form a multicolor image on the paper P.
[0070]
In this embodiment, as described above, the printer 22 including the head that discharges ink using the piezo element PE is used. However, a printer that discharges ink by another method may be used. For example, the present invention may be applied to a printer of a type that energizes a heater disposed in an ink passage and ejects ink by bubbles generated in the ink passage. In this embodiment, the number of colors used for printing can be changed by replacing only the ink cartridge, but printing can be performed by replacing the ink ejection mechanism in which the ink cartridge and the head are integrated. It may be possible to change the number of colors used.
[0071]
(2) Dot generation processing:
Next, the dot generation process in the present embodiment will be described. FIG. 12 is a flowchart of a dot formation control processing routine. This is a process executed by the CPU 81 of the computer 90. When this process is started, the CPU 81 inputs the image data and the type of cartridge (step S10).cartridgeIs detected by the identification sensor 29 of the printer 22 and transferred to the computer 90 side by communication. Of course, the user may input the cartridge type. The image data input in step S10 is data delivered from the application program 95 shown in FIG. 2, and 256 of values 0 to 255 for each color of R, G, and B for each pixel constituting the image. This is data having gradation values of steps. The resolution of the image data changes according to the resolution of the original image data ORG.
[0072]
The CPU 81 performs color correction processing on the input image data (step S20). The color correction process is a process for converting image data composed of R, G, B gradation values into gradation value data for each ink used in the printer 22. This process is performed using color correction tables LUT1 and LUT2 (see FIG. 2) that store combinations of inks for expressing the color composed of the combination of R, G, and B by the printer 22. In this embodiment, since the number of colors of ink used for printing differs depending on the type of ink cartridge, two color correction tables LUT1 and LUT2 are prepared, and color correction is performed by using these tables depending on the type of ink cartridge. Execute. Various known techniques can be applied to the color correction process itself using the color correction table. For example, an interpolation calculation process can be applied.
[0073]
The CPU 81 converts the resolution of the image data corrected in this way into a resolution for the printer 22 to print (step S30). When the image data ORG is lower than the printing resolution, resolution conversion is performed by generating new data between adjacent original image data by linear interpolation. Conversely, when the image data is higher than the print resolution, resolution conversion is performed by thinning out the data at a constant rate. When the resolution of the image data is a resolution that can be directly printed by a printer, printing may be performed without performing such processing.
[0074]
Here, in this embodiment, printing is performed with different resolutions for each color according to the type of the ink cartridge. The relationship between the cartridge type and the resolution is shown in FIG. When a four-color cartridge 72A is installed, yellow is printed at a resolution of 720 DPI (dots per inch) in the main scanning direction and 360 DPI in the sub-scanning direction, and the other colors are printed at a resolution of 720 DPI in both directions. Print. In the case of the four-color cartridge 72A, since the number of yellow nozzles is half that of the other colors, the resolution of only yellow is lowered. On the other hand, when the six-color cartridge 72B is mounted, the number of nozzles is the same for all color inks, so printing is executed at a resolution of 720 DPI in both the main scanning direction and the sub-scanning direction. In step S30, the CPU 81 sets the resolution as shown in FIG. 13 according to the type of the ink cartridge, and converts the data to each resolution.
[0075]
FIG. 14 shows the state of the pixels in this example. A square indicated by a solid line or a broken line in the figure means a pixel. As shown in FIG. 14A, the pixels are two-dimensionally arranged on the printing paper P in the main scanning direction and the sub-scanning direction. A small cell including a broken line indicates a pixel of 720 DPI in the main scanning direction and a pixel of 720 DPI in the sub scanning direction, and a large cell including only a solid line indicates a pixel of 720 DPI in the main scanning direction and 360 DPI in the sub scanning direction. ing. As described above, when the four-color cartridge 72A is mounted, dots of yellow ink are formed in units of pixels having a large 360 DPI, and dots of other colors are formed in units of small pixels.
[0076]
FIG. 14B shows an enlarged view of dot formation. The yellow ink is formed in units of 360 DPI pixels, but the dot formation position is based on 720 DPI pixels. Accordingly, as shown in FIG. 14B, the dots D1 and D2 can be formed by all inks including yellow, and the adjacent dots D3 and D4 below can be formed by inks other than yellow. . In this embodiment, in order to form dots in such a manner, when the four-color cartridge 72A is mounted, if dots are formed in all the pixels, the yellow dot recording rate becomes about half of the recording rate of other colors. .
[0077]
On the other hand, when the six-color cartridge 72B is installed, printing is performed at a resolution of 720 DPI for all colors. Accordingly, the dots D1 to D4 in FIG. 14B are dots that can be formed by all inks.
[0078]
When the color correction and the resolution conversion are completed, the CPU 81 performs a halftone process for each ink. Halftone processing refers to setting the dot on / off for each pixel so that the gradation value of the original image data (256 gradations in this embodiment) is expressed according to the dispersibility of the dots. . FIG. 15 is a flowchart of halftone processing. In this embodiment, halftone processing is performed by applying a so-called error diffusion method.
[0079]
When the halftone process is started, the CPU 81 inputs the image data CD (step S105). Further, the correction data CDX reflecting the diffusion error in the image data CD is generated (step S110). In the error diffusion method, a local density error generated in a pixel for which dot on / off has been determined is diffused to surrounding unprocessed pixels at a predetermined rate. The pixel of interest that is trying to determine whether the dot is on or off determines whether the dot is on or off after reflecting the error diffused from the processed pixel in the gradation data. The density error generated as a result of determining whether the pixel of interest is on or off is further diffused to surrounding unprocessed pixels. The ratio of diffusing the error is shown in FIG. The density error generated in the pixel of interest PP is diffused over several pixels in the scanning direction of the carriage and in the paper transport direction at a rate shown in the drawing. In order to determine dot on / off in such processing, in step S110, the diffused error is added to the image data CD to obtain correction data CDX.
[0080]
Next, it is determined whether or not the generated correction data CDX is equal to or greater than a predetermined threshold value TH (step S115). If the correction data CDX is greater than or equal to the threshold value TH, it is determined that a dot should be formed, and a value 1 is input to the result value RD that stores the determination result (step S125). If the correction data CDX is smaller than the threshold value TH, it is determined that no dot should be formed, and a value 0 is input to the result value RD (step S120). The predetermined threshold value TH is a value serving as a reference for determining on / off of dots, and may be set to any value. In this embodiment, the threshold value is set to an intermediate value of 256 gradations that the image data can take, that is, 128.
[0081]
When the dot is turned on / off, the CPU 81 performs error calculation and error diffusion processing based on the result value RD (step S130). The error is an error between the density expressed when the dot is turned on or off in the pixel of interest PP according to the multi-value conversion result and the density to be expressed based on the correction data CDX. The density expressed when dots are formed on the target pixel PP is obtained based on the density evaluation value RV set in advance for each pixel.
[0082]
The error ERR is obtained by ERR = RV−CDX using the correction data CDX and the density evaluation value RV. For example, assuming that the dot density evaluation value is equivalent to 255 in the gradation data, if the dot is formed even though the correction data CDX has a value of 199, 199-255 = −56. A density error has occurred. This means that the density expressed by the pixel is too dark.
[0083]
The error diffusion is a process of diffusing the error thus obtained by applying the predetermined weight shown in FIG. 16 to pixels around the pixel of interest PP. The error is diffused to the unprocessed pixels. If the error is “−56”, “−14” corresponding to ¼ of the error “−56” is diffused to the pixel adjacent to the currently processed pixel PP. This error is reflected in step S110 when the pixel P1 is processed next. For example, if the gradation data of the pixel P1 is a value 214, the diffused error “−14” is added and the correction dataCDXIs a value of 200. When the CPU 81 executes the above-described processing for all pixels (step S135), the CPU 81 ends the halftone processing routine and returns to the dot formation control processing routine.
[0084]
For the halftone process, various known methods such as the dither method as well as the above-described error diffusion method can be applied. In this embodiment, the halftone process is executed independently for each ink. However, the halftone process with a correlation between predetermined inks may be performed. For example, when the six-color cartridge 72B is mounted, the cyan ink and the light cyan ink may be correlated to perform processing so that dots formed by both inks do not overlap. Of course, it is also possible to have a correlation between inks having different hues.
[0085]
When the halftone processing is thus completed, the CPU 81 rasterizes the data for each pixel and outputs the data to the printer 22 (steps S200 and S210). Rasterization refers to a process of rearranging print data that has undergone halftone processing in the order of transfer to the printer 22. The rearranged print data is output from the computer 90 to the printer 22 through a serial or parallel transfer cable (step S210). The CPU 41 of the printer 22 stores the received print data in the drive buffer 47 and outputs the print data to the distribution output device 55 at a predetermined timing according to the movement of the carriage 31 to print an image.
[0086]
FIGS. 17 and 18 show how dots are formed by the printer 22. FIG. 17 is an explanatory diagram showing how dots are formed when the four-color cartridge 72A is mounted. For the sake of illustration, a head having six nozzles is shown. Circle or square symbols enclosing the numbers on the left side of the figure indicate the positions of the nozzles in the first to seventh main scans, respectively. Here, the first nozzle, the third nozzle, and the fifth nozzle indicated by the circle symbols correspond to the yellow nozzle positions. The 1st to 6th nozzles indicated by both the round and square symbols correspond to the nozzle positions of other colors. As shown in the figure, the pitch k1 of the other color nozzles is 5 dots, and the pitch k2 of the yellow nozzles is 10 dots.
[0087]
When the number of nozzles and the nozzle pitch are in the above relationship, an image can be printed on the printable area in the drawing by performing sub-scanning with a constant feed amount of 6 dots. On the right side of the figure, the state of dots formed in such a region is shown. Each dot is printed at a resolution of 720 DPI in the main scanning direction and the sub-scanning direction. Each dot shape corresponds to the shape of a nozzle symbol. If sub-scanning is performed with such a feed amount, rasters (rasters indicated by circles) formed by yellow nozzles appear every other raster. Therefore, yellow dots are printed in the sub-scanning direction at a resolution of 360 DPI, that is, the resolution described with reference to FIG.
[0088]
On the other hand, FIG. 18 shows a state where the six-color cartridge 72B is mounted on the same head. When the 6-color cartridge 72B is mounted, the nozzle pitch is equivalent to 10 dots for all color inks. The first nozzle, the third nozzle, and the fifth nozzle indicated by the circle symbols in FIG. 18 correspond to the yellow, cyan, and magenta nozzle positions. The second, fourth, and sixth nozzles indicated by the square symbols correspond to the light cyan and light magenta nozzle positions. The 1st to 6th nozzles correspond to the black nozzle positions.
[0089]
In this case, the sub-scan is performed with a constant feed amount for 3 dots. In the printable area in the figure, the sub-scan is executed so that both the nozzles indicated by the circle symbols and the nozzles indicated by the square symbols pass through each raster. Therefore, dots of all colors can be formed in this area, and an image can be printed. For black, two nozzles pass for each raster in the printable area. Accordingly, the dots may be formed only by any one of the nozzles. Alternatively, dots may be recorded by an overlap method in which dots are formed only on odd-numbered pixels at the first time and dots are formed only on even-numbered pixels at the second time. 17 and 18, the head having six nozzles has been described as an example. However, for the head having the nozzles shown in FIGS. 7 and 8, by setting the feed amount according to the ink cartridge, Printing can be performed appropriately.
[0090]
According to the printer 22 of the present embodiment described above, the head 28 can be reduced in size by reducing the number of yellow nozzles. For this reason, it is possible to reduce vibration and noise when printing is performed, power for driving the head, and the like.
[0091]
In addition, the number of colors used for printing can be changed by replacing the color ink cartridges 72A and 72B. Therefore, it is possible to realize printing according to the user's application. For example, in order to realize high-quality printing excellent in gradation expression, printing may be performed by mounting the six-color cartridge 72B. In order to realize high-speed printing, the four-color cartridge 72A may be mounted for printing.
[0092]
When the four-color cartridge 72A is mounted, the number of nozzles is reduced only for yellow, and printing is performed with coarse resolution only for yellow as described above. However, since the effect of yellow on image quality is relatively small, there is no significant deterioration in image quality even if the resolution of the yellow is coarsened. In the printer 22 of the present embodiment, the number of nozzles is reduced for the ink having a small influence on the image quality in this way, thereby realizing a reduction in the size of the head 28 without extremely degrading the image quality.
[0093]
In this embodiment, the yellow ink density is increased in the four-color cartridge 72A. As a result, even if the number of yellow dots is small, composite black can be appropriately expressed together with cyan and magenta. Therefore, even if yellow is printed at a coarse resolution in the four-color cartridge 72A, black gradation expression is not impaired.
[0094]
In the four-color cartridge 72A of this embodiment, the yellow ink capacity is half that of the other colors. In this way, color ink can be used evenly, and waste can be suppressed. In addition, since the printer 22 has a function of automatically determining the type of cartridge, the printer 22 erroneously performs processing corresponding to the six-color cartridge 72B even though the four-color cartridge 72A is mounted. The reverse situation can be avoided and waste due to a printing mistake can be avoided.
[0095]
The printer 22 of the present embodiment can be variously modified. In the above-described embodiment, the nozzles are arranged in a staggered pattern. However, as shown in FIGS. FIG. 19 shows the correspondence between colors and nozzle rows when the four-color cartridge 72A is mounted, and FIG. 20 shows the correspondence between colors and nozzle rows when the six-color cartridge 72B is installed. The configuration in which ink is supplied for each nozzle row is the same as in the above-described embodiment.
[0096]
An example of the print resolution when such an arrangement is employed is shown in FIG. When the four-color cartridge 72A is mounted, yellow is printed at a resolution of 360 DPI in the main scanning direction and 720 DPI in the sub-scanning direction. The other colors are printed at a resolution of 720 DPI on both sides. When the six-color cartridge 72B is installed, printing is performed at a resolution of 720 DPI in both the main scanning direction and the sub-scanning direction for all colors.
[0097]
FIG. 22 is an explanatory diagram showing a state of a pixel. In the embodiment described above, when the four-color cartridge 72A is mounted, dots are formed in units of pixels that are long in the sub-scanning direction, whereas in the modification, dots are formed in units of pixels that are long in the main scanning direction. Is different in that is formed.
[0098]
FIG. 23 is an explanatory diagram showing how dots are formed when a four-color cartridge 72A is mounted in a modified example. For convenience of illustration, the case where three nozzles are provided in the sub-scanning direction at a 2-dot pitch is shown as an example. FIG. 23A shows how dots are formed for cyan ink. The left side of the drawing shows the position of the head in the sub-scanning direction in the first to third main scans, and the right side shows how dots are formed. A circled symbol indicates a nozzle number. The symbol “C” means cyan. Of the two digits, the tenth digit indicates the nozzle row number, and the first digit indicates the nozzle sub-scanning direction number.
[0099]
The circles shown on the right side of the figure indicate the numbers of the nozzles that form each dot. As shown in the drawing, an image can be printed by forming every other dot in the main scanning direction by two nozzle rows. The same applies to magenta and black.
[0100]
FIG. 23B shows how dots are formed for yellow. Yellow has only one nozzle row. Therefore, if ink is ejected at the same timing as in the case of cyan ink shown in FIG. 23A, dots are formed every other pixel in the main scanning direction as shown on the right side of the figure. If the moving speed of the carriage 31 is reduced, it is possible to form all the pixels in the main scanning direction with yellow. However, in this case, there is no merit of providing two nozzle rows in the main scanning direction for other colors. In the modified example, the printing speed is improved by forming yellow at every other pixel in the main scanning direction.
[0101]
FIG. 24 shows how dots are formed when the six-color cartridge 72B is mounted. When the six-color cartridge 72 is mounted, there is one nozzle row for each color ink. Accordingly, the two nozzle rows of cyan ink shown in FIG. 23A are divided into three nozzles C1 to C3 for cyan and three nozzles LC1 to LC3 for light cyan as shown in FIG. It becomes a corresponding state.
[0102]
The state of dot formation is shown on the right side. The number in each dot corresponds to the nozzle number. When a six-color cartridge is mounted, each head moves the carriage 31 at a speed at which dots can be formed on all pixels, and executes printing. FIG. 24B shows how dots are formed for yellow. When the six-color cartridge 72B is mounted, since the moving speed of the carriage 31 is low, dots can be formed on all the pixels. Therefore, yellow dots can be formed on all the pixels in the printable area in the drawing. The same applies to other color inks. As for the black ink, the surplus nozzles can be applied to various printing methods as in the above-described embodiments.
[0103]
In the embodiments and modifications described above, the black ink cartridge has been described as not being replaced. For this reason, in the above-described embodiment, the black ink is supplied from the one introduction pipe 73 to the two nozzle rows. On the other hand, black can be replaced with an ink cartridge having a different density by adopting a configuration in which ink is supplied from two introduction tubes for each nozzle row. For example, as shown in FIG. 25, dark and light black ink can be supplied to the nozzle rows one by one.
[0104]
It is not always necessary to supply ink in units of nozzle rows. As shown in FIG. 26, the print head may be divided into two in the sub-scanning direction, and ink may be supplied for each unit pattern of C1, C2, M1, and M2. In this way, when a four-color cartridge is mounted, printing with four colors can be performed by supplying the same cyan ink to C1 and C2 and the same magenta ink to M1 and M2. When a six-color cartridge is installed, printing with six colors can be performed by supplying cyan ink to C1, light cyan ink to C2, magenta ink to M1, and light magenta ink to M2. Such an arrangement has an advantage that bleeding can be suppressed because inks having different densities are not continuously ejected to the same raster in one main scanning.
[0105]
According to the printing apparatus of this embodiment described above, halftone processing is performed by so-called binarization in which dot on / off is determined for each pixel. On the other hand, a plurality of types of dots having different ink amounts can be formed, and multi-value conversion of three or more values may be performed for each pixel. In such a case, it is not necessary to match the multi-value gradation values for all the colors. Only the yellow having little influence on the image quality may be binarized, and the other colors may be multi-valued. Conversely, when the four-color cartridge 72A is mounted, only yellow may be multi-valued in order to compensate for a coarse resolution.
[0106]
In the present embodiment, when the four-color cartridge 72A is installed, printing is performed with respect to yellow at half the resolution of other colors. The resolution of yellow is not limited to this, and various resolutions can be set. For example, it is possible to print at half the resolution of other colors in both the main scanning direction and the sub-scanning direction. When printing at such a resolution, it is desirable to make the yellow ink darker as the resolution is lowered.
[0107]
In the present embodiment, when the four-color cartridge 72A is mounted, image data with coarse resolution is prepared for yellow and halftone processing is executed. In order to print at a resolution different from that of other colors, various other methods can be employed. For example, halftone processing is executed with respect to yellow with the same resolution as other colors, but the density evaluation value in the error diffusion method may be manipulated to make it difficult for dots to be formed in adjacent pixels. Alternatively, after halftone processing is performed at the same resolution as that of the other colors, the dot arrangement may be changed between adjacent pixels to generate data with coarse resolution.
[0108]
In the present embodiment, no specific processing is provided when the four-color cartridge 72A and the six-color cartridge 72B are replaced. On the other hand, when it is detected that a cartridge with a different number of colors is mounted, a function of washing the head 28 can be added in order to avoid color mixing with conventional ink. Such cleaning can be performed, for example, by ejecting newly loaded ink from the nozzles when the carriage 31 is in the retracted position. When the four-color cartridge 72A is replaced with the six-color cartridge 72B, the low-density ink is supplied to the nozzle to which the high-density ink was supplied before the replacement. Therefore, in this case, the cleaning time may be longer than when the six-color cartridge 72B is replaced with the four-color cartridge 72A. For these cleanings, a cleaning liquid prepared separately from the ink of each cartridge may be used. Moreover, you may employ | adopt the structure which can replace | exchange a cartridge and a nozzle integrally.
[0109]
In the above embodiments, the ink jet printer 22 has been described as an example. In the above-described embodiments, an inkjet printer having a piezo element has been described as an example. However, various printers and other types of printing such as a printer that discharges ink by bubbles generated in ink by energizing a heater provided in a so-called nozzle are used. Applicable to the device. Further, the present invention can be applied to a printing apparatus other than a printer as long as the apparatus expresses an image by assigning dots to each pixel.
[0110]
Although various embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various embodiments can be implemented without departing from the spirit of the present invention. For example, some or all of the various control processes described in the above embodiments may be realized by hardware.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a printing apparatus according to an embodiment.
FIG. 2 is an explanatory diagram illustrating a software configuration of the printing apparatus according to the present exemplary embodiment.
FIG. 3 is a schematic configuration diagram of a printer 22;
4 is a perspective view of a carriage 31. FIG.
FIG. 5 is a perspective view of a four-color cartridge 72A.
FIG. 6 is a perspective view of a six-color cartridge 72B.
FIG. 7 is an explanatory diagram showing a correspondence relationship between nozzle arrangement and colors when a four-color cartridge 72A is mounted.
FIG. 8 is an explanatory diagram showing a correspondence relationship between nozzle arrangement and colors when a six-color cartridge 72B is mounted.
FIG. 9 is an explanatory diagram showing setting of each ink density.
FIG. 10 is an explanatory diagram illustrating a dot formation principle of the printer 22;
11 is an explanatory diagram showing a configuration of a control circuit 40 of the printer 22. FIG.
FIG. 12 is a flowchart of a dot formation control processing routine.
FIG. 13 is an explanatory diagram showing a relationship between an ink cartridge and resolution.
FIG. 14 is an explanatory diagram showing a state of a pixel.
FIG. 15 is a flowchart of a halftone processing routine.
FIG. 16 is an explanatory diagram showing weight values for error diffusion;
FIG. 17 is an explanatory diagram showing how dots are formed when a four-color cartridge 72A is mounted.
FIG. 18 is an explanatory diagram showing how dots are formed when a six-color cartridge 72B is mounted.
FIG. 19 is an explanatory diagram showing a correspondence relationship between a nozzle arrangement and colors in a modified example in which a four-color cartridge 72A is mounted.
FIG. 20 is an explanatory diagram showing a correspondence relationship between a nozzle arrangement and colors in a modified example in which a six-color cartridge 72B is mounted.
FIG. 21 is an explanatory diagram illustrating a relationship between an ink cartridge and resolution in a modified example.
FIG. 22 is an explanatory diagram showing a state of a pixel in a modified example.
FIG. 23 is an explanatory diagram showing how dots are formed when a four-color cartridge 72A according to a modification is mounted.
FIG. 24 is an explanatory diagram showing how dots are formed when a six-color cartridge 72B according to a modification is mounted.
FIG. 25 is an explanatory diagram illustrating a correspondence relationship between a nozzle arrangement and a color according to a second modification.
FIG. 26 is an explanatory diagram illustrating a correspondence relationship between a nozzle arrangement and a color according to a third modification.
[Explanation of symbols]
12 ... Scanner
14 ... Keyboard
16. Hard disk
18 ... modem
22 Color printer
23 ... Motor
24 ... Carriage motor
26 ... Platen
28 ... Print head
29 ... Identification sensor
31 ... Carriage
32 ... Control panel
34 ... Sliding shaft
36 ... Drive belt
38 ... pulley
39 ... Position detection sensor
40 ... Control circuit
45. Peripheral input / output section
46 ... Timer
47 ... Drive buffer
48 ... Bus
51 ... Transmitter
55 ... Distribution output device
68 ... Ink passage
71 ... cartridge for black ink
72A, 72B ... cartridge for color ink
73-78 ... introduction pipe
80 ... Bus
81 ... CPU
82 ... RAM
83 ... ROM
84 ... Input interface
85 ... Output interface
86 ... CRTC
87: Disk controller
88 ... Serial I / O interface
90 ... Computer
91 ... Video driver
95 ... Application program
96 ... Printer driver
97 ... Resolution conversion module
98 ... Color correction module
99 ... Halftone module
100 ... Rasterizer
101: Cartridge determination unit

Claims (3)

A printing apparatus that prints a multicolor image by forming dots according to image data on a print medium by a head having a plurality of nozzles that form dots by ejecting ink,
In a state where a plurality of predetermined unit patterns are arranged for nozzles to which chromatic ink other than the specific color is to be supplied, a head including the plurality of nozzles;
It is a mounting unit that replaceably mounts a predetermined ink cartridge including an ink storage unit that stores ink of each color, and can supply the specific color ink from the ink storage unit to a certain nozzle of the head, And a mounting unit including a plurality of ink introduction paths capable of supplying a single color of ink to each nozzle for each unit pattern from the ink storage unit for chromatic color ink other than the specific color,
The number of the fixed nozzles corresponding to the specific color ink is equal to the number of nozzles for one unit pattern,
The printing apparatus further includes:
Detecting means for identifying the number of inks contained in the ink cartridge mounted on the mounting unit based on an identification unit provided in the ink cartridge mounted on the mounting unit;
Based on the number of inks, the ink supplied to the unit patterns from the ink cartridge mounted on the mounting unit and the ink supplied to the certain nozzles from the ink cartridge mounted on the mounting unit And a dot formation determination unit that sets on / off of dots by each ink for each pixel. The printing apparatus according to claim 1,
For a pixel having a resolution set based on the number of nozzles for each color, multi-value conversion means for performing halftone processing based on the image data for each color;
A printing apparatus comprising: a dot forming unit that drives the nozzle according to the processing result to form dots with a resolution set for each color. The printing apparatus according to claim 1,
A head drive unit that forms dots by performing main scanning that reciprocates the head in one direction and sub-scanning that drives the print medium relative to the head in a direction that intersects the direction of the main scanning;
The head is
The specific color nozzles are provided in a plurality of arrangements at a predetermined pitch in the sub-scanning direction, and
A printing apparatus which is a head including the nozzles of the other colors in an arrangement in which the positions of the nozzles of the specific color coincide with the positions in the sub scanning direction.

Images