JP5080959B2 - Data generation method and data generation apparatus - Google Patents

Description

The present invention relates to a data generation method and a data generation apparatus .

  As one of image forming apparatuses, there is an ink jet printer that forms an image by ejecting liquid or solid ink. When forming a multi-gradation image in this ink jet printer, conventionally, gradation representation is performed by changing the density of dots using two gradations with or without dots. However, when an image such as a photograph is formed by such a method, there is a problem that graininess is generated.

  As a means for solving this problem, for example, Patent Document 1 discloses a method in which inks having different densities are used, dark ink is used in a high density part, and light ink is used in a low density part. It is disclosed. Similarly, it has a recording element array for recording dots having a large diameter (large dots) and a recording element array for recording dots having a small diameter (small dots). A method of expressing gradation by recording dots having a small diameter in a low-part portion is also considered.

  In a recording apparatus using these methods, ink is supplied from the ink cartridge, but the ink consumption directly affects the running cost of the recording apparatus, and the user's interest is in line with the recording speed and recording quality. It will be very expensive.

  Up to now, as means for saving ink, for example, Patent Document 2 has an energy saving mode for reducing running costs, and when that mode is set, the recording density is automatically reduced or the recording size is reduced. Is disclosed.

  On the other hand, various ink cartridges are used in the recording apparatus.

  In the case of an integrated cartridge in which ink tanks containing a plurality of inks are integrated, color recording cannot be performed if any one of the plurality of inks is exhausted. When such an integrated cartridge is used, the ink consumption balance of each color also affects the ink running cost.

  On the other hand, in the case of a stand-alone cartridge in which a plurality of inks are stored in separate ink tanks, only the ink tanks that have been emptied are replaced, so even if the ink consumption balance of each color is biased, the cartridge It is only necessary to increase the number of exchanges. For this reason, the ink consumption does not directly affect the running cost. Hereinafter, this ink consumption is referred to as narrow ink running cost.

  On the other hand, in Patent Document 3, the ink consumption is measured, the cumulative value of the consumption is calculated and stored, and the calculation is performed so as to equalize the cumulative consumption in the ink tanks containing the inks of the respective colors. It is disclosed that the color mixture ratio is changed or the recording pattern is changed. Thereby, the ink consumption balance can be equalized.

Further, in Patent Document 4, in a system in which a plurality of similar color inks supplied from a plurality of independent ink tanks exist, priority is given to a similar color ink with a large amount of remaining ink when recording a specific color. A method of making the remaining amount of ink uniform by using it is disclosed. That is, when the remaining amount of ink in the ink tank containing dark ink (or used for recording large dots) is small, light ink (or used for recording small dots) is preferentially used. . Conversely, when the ink level of the light ink (or used for recording small dots) ink tank is small, the dark ink (or used for recording large dots) ink tank is preferentially used. In this way, the ink consumption balance is equalized by switching and using the ink tank.
JP 58-39468 A JP-A-6-19257 JP-A-8-108548 Japanese Patent Laid-Open No. 11-78060

  However, the conventional example has various problems as described below.

  For example, according to the method described in Patent Document 2, it is possible to save the ink running cost, but there is a problem that the size and density of the output image change.

  In addition, even when a stand-alone cartridge is used, there is a problem that user convenience is not good due to uneven ink consumption balance such as time for cartridge replacement and waiting time for ink filling at the time of replacement. It will occur. In the following, in addition to ink consumption, those including the trouble of replacing the cartridge and the waiting time for ink filling at the time of replacement are referred to as ink running cost in a broad sense. Accordingly, the fact that this ink consumption balance is uniform also affects the ink running cost in a broad sense.

  Furthermore, the method described in Patent Document 3 has a problem that the reproduction color changes because the color mixture ratio is changed.

  Furthermore, the method described in Patent Document 4 is effective in a system in which similar-color dark and light inks are supplied from separate ink tanks, but when printing large and small dots, different inks are used depending on the dot diameter. Ink is not necessarily supplied from the tank. Therefore, there is a problem that this method cannot be applied when ink for recording dots having different diameters is supplied from a single ink tank.

The present invention has been made in view of the above conventional example, and a data generation method capable of performing high-quality recording with droplets having different sizes from a recording head by ink supplied from an ink tank while reducing the cost of ink consumption. And it aims at providing a data generation device .

In order to achieve the above object, the data generation method of the present invention comprises the following steps .

That is, by communicating with an ink tank containing ink of a predetermined color and applying a first ink droplet and a second ink droplet having a size larger than the first ink droplet from the recording head to the recording medium. A data generation method for generating recording data for forming an image, wherein the first ink droplet is applied to a unit area of the recording medium with respect to a signal value corresponding to the recording data for forming the image. A first setting step for determining a first application amount for application and a second application amount for applying the second ink droplet; and corresponding to recording data for forming the image. With respect to the signal value, a third application amount that is an application amount for applying the first ink droplet to the unit region and is larger than the first application amount, and the second ink droplet is applied. The amount to be applied and the second The first ink droplet is selected by selecting one of a second setting step for determining a fourth application amount that is smaller than the given amount, the first setting step, and the second setting step. In the second setting step when the signal value is in a predetermined range, and a generation step for generating the recording data for applying the second ink droplet and the recording data for applying the second ink droplet. The sum of the third grant amount and the fourth grant amount determined is less than the sum of the first grant amount and the second grant amount determined in the first setting step. Features.

According to another invention , the first ink droplet and the second ink droplet larger in size than the first ink droplet are recorded from the recording head in communication with an ink tank that stores ink of a predetermined color. A data generation device that generates recording data for forming an image by applying to a medium, wherein the signal value corresponding to the recording data for forming the image is stored in a unit area of the recording medium. First setting means for determining a first application amount for applying the first ink droplet and a second application amount for applying the second ink droplet, and for forming the image A third application amount that is an application amount for applying the first ink droplet to the unit area and is greater than the first application amount, with respect to the signal value corresponding to the recording data of With an application amount for applying 2 ink droplets Then, a second setting means for determining a fourth grant amount smaller than the second grant amount is selected, and one of the first setting means and the second setting means is selected, and Generating means for generating recording data for applying the first ink droplet and recording data for applying the second ink droplet, and when the signal value is within a predetermined range, The sum of the third grant amount and the fourth grant amount determined by the second setting means is the sum of the first grant amount and the second grant amount determined by the first setting means. The data generation device is characterized by being less than the above .

  Therefore, according to the present invention, it is possible to make the consumption amounts of a plurality of inks as uniform as possible even in color recording, for example, while maintaining high image quality. Thereby, for example, even in a configuration in which one head cartridge has a plurality of ink tanks, the ink stored in each ink tank can be consumed as uniformly as possible. Accordingly, it is possible to reduce the number of situations where a certain ink is lost and a lot of other ink remains as much as possible, and to reduce the chance that the head cartridge is discarded while the ink remains. Further, the replacement of the head cartridge can be reduced, and the running cost can be reduced.

  Hereinafter, preferred embodiments of the present invention will be described more specifically and in detail with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the already demonstrated part and duplication description is abbreviate | omitted.

  In this specification, “recording” (sometimes referred to as “printing”) is not limited to the case of forming significant information such as characters and graphics, but may be significant. It also represents the case where an image, a pattern, a pattern, etc. are widely formed on a recording medium, or the medium is processed, regardless of whether it is manifested so that humans can perceive it visually. .

  “Recording medium” refers not only to paper used in general recording apparatuses but also widely to cloth, plastic film, metal plate, glass, ceramics, wood, leather, and the like that can accept ink. Shall.

  Further, “ink” (sometimes referred to as “liquid”) should be interpreted widely as in the definition of “recording (printing)”. Therefore, by being applied on the recording medium, it is used for formation of images, patterns, patterns, etc., processing of the recording medium, or ink processing (for example, solidification or insolubilization of the colorant in the ink applied to the recording medium). It shall represent a liquid that can be made.

  Furthermore, a “nozzle” (sometimes referred to as “recording element” or “recording element”) is an element that generates energy used for ejection ports or liquid passages communicating therewith and ink ejection unless otherwise specified. I will sum up and say.

<Description of Inkjet Printer (FIGS. 1 to 4)>
FIG. 1 is an external perspective view showing an outline of the configuration of an ink jet printer (hereinafter referred to as a recording apparatus) IJRA which is a typical embodiment of the present invention.

  In FIG. 1, the carriage HC engaged with the spiral groove 5004 of the lead screw 5005 that rotates via the driving force transmission gears 5009 to 5011 in conjunction with the forward / reverse rotation of the motor 5013 has a pin (not shown). ing. The carriage HC is supported by the guide rail 5003 and reciprocates in the directions of arrows a and b. An integrated head cartridge IJC incorporating a recording head IJH and an ink tank IT is mounted on the carriage HC. The paper pressing plate 5002 presses the recording paper P against the platen 5000 in the moving direction of the carriage HC.

  The photocouplers 5007 and 5008 operate as home position detectors for confirming the presence of the carriage lever 5006 in this region and switching the rotation direction of the motor 5013 and the like. A cap member 5022 that caps the front surface of the recording head IJH is supported by a member 5016. Then, the suction unit 5015 sucks the inside of the cap, and performs the suction recovery of the recording head through the opening 5023 in the cap. The cleaning blade 5017 can be moved in the front-rear direction by a member 5019, and these are supported by a main body support plate 5018. Needless to say, the blade is not in this form, and a known cleaning blade can be applied to this example.

  A lever 5021 for starting suction for suction recovery moves as the cam 5020 engaged with the carriage HC moves, and the drive force from the drive motor is controlled by a known transmission mechanism such as clutch switching.

  These capping, cleaning, and suction recovery are configured such that a desired process can be performed at the corresponding position by the action of the lead screw 5005 when the carriage reaches the region on the home position side. However, any desired application can be applied to this example as long as a desired operation is performed at a known timing.

  FIG. 2 is an external perspective view showing a configuration of a head cartridge IJC in which an ink tank and a recording head are integrally formed.

  In FIG. 2, a dotted line K is a boundary line between the ink tank IT and the recording head IJH. The head cartridge IJC is provided with an electrode (not shown) for receiving an electrical signal supplied from the carriage HC when it is mounted on the carriage HC, and the recording head IJH is driven by this electrical signal. Ink is ejected.

  In FIG. 2, reference numeral 500 denotes an ink discharge port array. The ink tank IT is provided with a fibrous or porous ink absorber to hold ink.

  FIG. 3 is a diagram showing the internal structure of the head cartridge IJC.

  As shown in FIG. 3, the ink tank IT built in the head cartridge IJC has separate liquid chambers for storing four inks. That is, a C ink chamber containing cyan (C) ink, an M ink chamber containing magenta (M) ink, a Y ink chamber containing yellow (Y) ink, and a Y ink containing black (Y) ink. It is an ink liquid chamber.

  Further, the recording head IJH is provided with two recording element arrays each for ejecting ink of each color. In order to distinguish these, in FIG. 3, it has shown as C, c, M, m, Y, y, K, and k. That is, the recording element array 15a used for recording dots having a large diameter (large dots) and the recording element array 15b used for recording dots having a small diameter (small dots). These two recording element arrays form a set and communicate with one corresponding ink liquid chamber. Each of the four ink chambers is provided with a remaining ink sensor 17.

  With the configuration described above, gradation expression can also be achieved by using the same ink for each color and ejecting ink droplets having different dot diameters from the recording element array 15a and the recording element array 15b. Of course, different inks corresponding to the respective dot diameters may be used when changing the dot diameters.

  The ink used may be liquid ink or solid ink (toner). Here, a configuration is adopted in which large and small dots are separated from nozzles having two different diameters, but a configuration in which three or more dots are separated may be employed, or multiple size dots may be emitted from a single nozzle capable of dot modulation. It is good also as a structure to divide.

  As shown in FIG. 3, in addition to the configuration in which a plurality of ink liquid chambers are integrally stored in the head cartridge IJC, a head cartridge in which each ink liquid chamber is independent is used. You can also. In this case, as shown in FIG. 3, all the ink liquid chambers do not have to be integrated, and may be composed of several cartridges.

  FIG. 4 is a diagram showing the internal structure of the independent head cartridge.

  In the example shown in FIG. 4, four head cartridges each including an ink tank that stores one ink and a recording head that includes two recording element arrays are mounted. These four head cartridges IJC-1, IJC-2, IJC-3, and IJC-4 can be independently replaced. In this example, an ink remaining amount sensor 17 is provided in each head cartridge.

  In the configuration shown in FIG. 4, the print head is built in each head cartridge. However, a print element array corresponding to several inks may be provided in one print head. Therefore, the ink tank and the recording head do not necessarily correspond.

<Control Configuration of Inkjet Printer (FIGS. 5 to 6)>
FIG. 5 is a block diagram showing a control configuration of the recording apparatus shown in FIG.

  As shown in FIG. 5, the controller 600 includes an MPU 601, a ROM 602, a special purpose integrated circuit (ASIC) 603, a RAM 604, a system bus 605, and the like. Here, the ROM 602 stores a program corresponding to a control sequence to be described later, a required table, and other fixed data. The ASIC 603 generates control signals for controlling the carriage motor M1, the transport motor M2, and the print head IJC. The RAM 604 is used as a recording data development area, a work area for program execution, and the like. A system bus 605 connects the MPU 601, the ASIC 603, and the RAM 604 to each other to exchange data.

  In FIG. 5, reference numeral 610 denotes a computer (or an image reading reader, digital camera, or the like) serving as a recording data supply source, and is collectively referred to as a host device. Between the host device 610 and the recording device IJRA, recording data, commands, status signals, and the like are transmitted and received via an interface (I / F) 611. The interface (I / F) is directly connected to the host device 610 via a cable or wireless, or indirectly via a network or the like. The recording data transferred from the host device 610 may be in any format such as code data, image data, intermediate data between image data and code data.

  The MPU 601 and the ASIC process image data received via the interface 611 to generate recording data to be supplied to the recording head IJC. For example, if the received image data is image data that expresses each pixel RGB component in a multi-value, this is processed to indicate whether ink is to be ejected for each pixel for each ink in each recording scan. Convert to binary data. At this time, various image processing is performed. For example, color conversion processing from the RGB color system to the YMCK color system, adjustment of color characteristics, γ characteristics, and the like are performed. Details of this will be described later.

  Further, 640 is a carriage motor driver that drives a carriage motor M1 for reciprocating scanning of the carriage HC in the direction of arrow A, and 642 is a conveyance motor driver that drives a conveyance motor M2 for conveying the recording medium P.

  The ASIC 603 transfers recording data to the recording head IJC while directly accessing the storage area of the RAM 604 during recording scanning by the recording head IJC.

  The recording head IJH is controlled by the controller 600 via the head driver 644. That is, the head driver 644 transfers the print data generated by the MPU 601 and the ASIC 603 to the print element arrays 15a and 15b of the print head IJC, and controls the timing of the print data to perform ink ejection control.

  The control panel 620 is provided with a power switch (not shown), an ink amount adjustment switch, a recording mode switch, and the like, and is used for image formation described later. It is not necessary to provide all such switches, and the host device 610 may be instructed. The control panel 620 may have a display function such as an LCD display or a touch panel, and other input functions.

  FIG. 6 is a diagram illustrating the contents of image processing executed by the MPU 601 and the ASIC 603.

  The RGB multivalued image data received via the interface (I / F) 611 is resolution-converted to the recording resolution of the printer by the resolution conversion processing 21. The resolution-converted image data is decomposed into CMYK planes of different colors by color separation conversion processing 22. The color separation method in the color separation conversion process 22 is defined by the color separation table 20.

  The color separation conversion process 22 accesses the color separation table 20 for determining the ink to be used or the recording dot diameter based on the ink remaining amount of each ink liquid chamber detected by the ink remaining amount sensor 17, and the ink remaining amount. The recording data is generated so as to suppress the consumption of ink with a small amount of ink. Such a process satisfies a predetermined condition, for example, when an ink whose remaining amount is equal to or less than a predetermined value is generated or when a difference from other ink is equal to or greater than a predetermined value. After that, control for suppressing consumption of ink with a small amount of ink may be performed.

  Further, it may be configured to determine according to the recording mode in which execution of such processing is designated. Since the threshold value is controlled as described above, the actual recording density may be slightly different, and a slight image quality degradation may occur. In order to prevent this, when the high image quality mode is designated as the recording mode or when the user designates that such processing is not performed, the ink can be used even if the ink remaining amount is low. It is also possible not to perform processing for suppressing consumption.

  Further, when the recording medium to be used is designated, the ink amount to be used may be controlled as described above according to the designated recording medium. When such control is performed, the control panel 620 or the host device 610 may be notified of that fact.

  The color-separated image data is converted into binary data by executing a halftone process 23 such as an error diffusion method for each plane. The converted pseudo halftone data is processed by the interlace processing 24 so as to match the nozzle array of the recording head, and is output to the system bus 605 as recording data.

  Next, several examples of image forming processing executed by discharging ink onto a recording medium using the recording apparatus having the above configuration will be described.

  In this embodiment, it is first determined whether or not it is possible to change the size ratio of large dots to small dots for suppressing ink consumption for ink with a small remaining amount. Here, when it is determined that the change is impossible, it is determined whether or not the size ratio of other ink colors with a large remaining amount can be changed to promote ink consumption. If it is determined that the change is possible, the size ratio of small dots to large dots is changed to equalize ink consumption for each color.

  FIG. 7 is a flowchart showing a process of changing the large / small dot ratio according to the result of the remaining ink amount detection.

  When the process is started, in step S20, the detection result from the ink remaining amount sensor 17 is checked for each color ink, thereby detecting the ink remaining amount.

  Next, in step S30, it is checked whether the detected ink remaining amount is equal to or less than a specified value. Here, if there is a remaining amount exceeding the specified value for all color inks, the process proceeds to step S90, and the process ends. On the other hand, if it is determined that the remaining amount of ink of any color is equal to or less than the specified value, the process proceeds to step S40. In step S40, it is checked whether or not there is room for increasing small dots for ink that is equal to or less than the specified value (small dot determination).

  If it is determined that there is room for increasing small dots, the process proceeds to step S50, and the size ratio change (large to small) of the ink with a small remaining amount is executed. The increase in the small dot usage ratio suppresses ink consumption of the ink that is the target of the large / small ratio change (large → small). On the other hand, if it is determined that there is no room to increase the small dots, the process proceeds to step S60 to determine whether there is room to increase the large dots of ink with a large remaining amount (large dots). Judgment).

  If it is determined that there is room to increase the large dots, the process proceeds to step S70, and the size ratio change (small to large) of the ink with a large remaining amount is executed. The increase in the large dot use ratio promotes ink consumption of the ink that is the target of the large / small ratio change (small → large). On the other hand, if it is determined that there is no room to increase the large dots, the process proceeds to step S80, and the large / small ratio change for both the small dot increase and the large dot increase cannot be executed. An error message indicating this is executed, and then the process ends.

  In order to notify the user that the recording data is generated so as to suppress the consumption of ink with a small amount of ink remaining, it is preferable to control the lamp for adjusting the ink amount of the control panel 620 to be lit.

  This error display is displayed on the LCD display provided on the control panel 620 or the display of the connected host device.

  In the example described above, the ink remaining amount is directly detected using the ink remaining amount sensor 17 provided in the ink liquid chamber or the ink tank of the inter cartridge. However, the present invention is not limited to this. . For example, the number of ink ejections from the recording head IJH may be counted, and the ink remaining amount may be indirectly detected from the count value. In this case, a counter that counts the number of ink ejections may be provided in the head driver 644 or the controller 600.

  Further, the process of adjusting the consumption of the ink amount by changing the large / small dot ratio may be automatically performed. However, the user determines whether or not to perform the process using the ink amount adjustment button provided on the control panel 620. May be specified.

  Next, a specific example of the above-described change in size ratio will be described.

  Here, large ink and small ink are used for four colors of cyan, magenta, yellow, and black, respectively, but in order to simplify the explanation, only one color ink will be described.

・ Recording with large and small dots (Dot distribution method according to the conventional example)
FIG. 8 is a diagram for explaining large and small dot distribution by the color separation table 20 used in the color separation conversion processing 22.

  This color separation is realized by a three-dimensional LUT (Look Up Table).

  FIG. 9 is a diagram showing a color separation table composed of a three-dimensional LUT.

  This LUT is a correspondence table of (C, c, M, m, Y, y, K, k) for a set of three-dimensional expression colors (R, G, B). It defines how to divide by dots. Here, C and c represent the density of large dots and small dots recorded with cyan ink, respectively. Similarly, M, m, Y, y, K, and k represent the densities of large dots and small dots that are recorded by magenta ink, yellow ink, and black ink, respectively. Each luminance density is expressed by 8 bits for each pixel. That is, the value of each luminance component of each pixel is 0 to 255, and the value of each density component of each pixel is 0 to 255.

  Here, in order to simplify the description, the case of color separation of the white → cyan gradation will be described with reference to FIG. 8 where only the white → cyan portion shown in FIG. 9 is extracted.

  In order to simplify the description, the distribution of large and small dots will be described as following a conventional method.

  In FIG. 8, the horizontal axis shows the change in color from white (R, G, B) = (255, 255, 255) to cyan (R, G, B) = (0, 255, 255). The vertical axis represents the ink usage in terms of density (0 to 255). Furthermore, the thick solid line indicates the amount of ink used to record small dots (c small dots) with cyan ink, and the thick dotted line indicates the amount of ink used to record large dots (large C dots) with cyan ink. The thin solid line indicates the total amount of ink in the large and small dots.

  As shown in FIG. 8, the total amount of cyan ink in the large and small dot sums monotonically increases from white to cyan, and is maximum in cyan. The amount of ink used for c small dots increases monotonically from white, and is used up to the maximum value that can be recorded with c small dots of intermediate colors between white and cyan. Since the density is insufficient only by recording c small dots, the large C dots start to be used from an intermediate color between white and cyan, and the ink usage of the large C dots monotonously increases toward cyan. That is, from the viewpoint of granularity, the highlight portion (low to medium density region) is composed of small dots, and large dots are used after the density is insufficient. When the large dots are used, the effect of improving the granularity by the small dots is reduced, and accordingly, the small dots become unnecessary, and the ink usage of the c small dots decreases monotonously.

  Further, the small dots are easily affected by the turbulence of the air flow generated by the reciprocating movement of the recording head and the ejection of the large dots. For this reason, recording is performed depending on the nature that the attachment position on the recording medium tends to be unstable, whether there is less overlap on the recording medium than large dots, and whether the attachment position shifts due to the accuracy of equipment parts, etc. There is a property that the state is easily changed. That is, in recording with small dots, resistance to changes in the recording state (robustness) tends to be weak, and therefore there is a tendency to use small dots in a density range where large dots can be used.

-Large and small dot recording mechanism Here, the large and small dot recording mechanism will be described in detail with reference to FIGS.

  FIG. 10 is a schematic diagram showing a state immediately after the large dot droplet and the small dot droplet are attached to the surface of the recording medium.

  Assuming that large dot droplets can be represented as spheres with radius r1 and small dot droplets with radius r2, the volume of these droplets is expressed by equation (1).

V = (4/3) πr ³ (1)
Immediately after adhering these droplets to the surface of the recording medium, the large dot becomes a cylinder having a radius R1 and a height h1, and the small dot is a cylinder having a radius R2 and a height h2. Assuming that the coating area on the surface of the recording medium after the adhesion of these droplets is a circle, the area is expressed by Equation (2).

S = πr ² (2)
Further, the radius after adhering to the surface of the recording medium is expressed as shown in Expression (3) using a bleeding rate n representing how to blur after adhering. That is, the “bleeding rate” indicates how many times the radius of the droplet is increased after adhesion. It is known that the bleeding rate is determined by the combination of the type of recording medium and the ink, and is about 2 for coated paper for inkjet and about 3 for plain paper.

R _j = nr _j (j = 1, 2) (3)
From the above examination, when formulas (1) to (3) are put together, formula (4) is obtained.

S = πn ² (3V / 4π) ^2/3 (4)
That is, it can be seen that the coating area after the droplets adhere is proportional to the square of the bleeding rate and proportional to the 2/3 power of the volume of the ink droplets. Therefore, the area is about 1.6 times when the volume is twice, the area is about 2.5 times when the volume is four times, and the area is about four times when the volume is eight times.

  FIG. 11 is a diagram showing a recording state of large dots.

  FIG. 11 shows that two main droplets and one of the satellites are attached.

  FIG. 12 shows a small dot recording state.

  In FIG. 11, the two main drops and the main drops are in a vertically aligned positional relationship, and satellites slightly smaller than the main drops are attached.

  The dot size ratio of the large and small dots used in this experiment is four times, but as is apparent from a comparison between FIG. 11 and FIG. 12, the large dot and the small dot on the recording medium surface after adhesion It is clear that the covering area ratio is less than 4 times. Furthermore, it was found that a value of about double that was close to the actual measurement value was obtained when the calculation was performed in consideration of the spherical breakage of the main droplet and the satellite.

  From the above considerations, instead of using large dots, using more small dots increases the coverage area on the surface of the recording medium after attachment that contributes to color development without increasing the amount of ink used. I found that I could do it.

-Distributing method of large and small dots (according to Example 1)
A case where many small dots are used based on the above examination will be described with reference to FIG.

  FIG. 13 is a diagram showing a part of the color separation table that defines the distribution of large and small dots from white to cyan, as in FIG. As can be seen from a comparison between FIG. 13 and FIG. 8, in this embodiment as well as FIG. 8, small dots are used from the middle of white to cyan, and the ink usage of the small dots that can be printed in the middle area is the maximum. Value. However, in this embodiment, recording with small dots is continued even from the middle to cyan, and the ink usage is kept at the maximum value. On the other hand, the large dots increase monotonously from the middle of white to cyan, as shown in FIG. 8, but since the small dots have already been recorded in cyan, they are increased by the amount obtained by subtracting the corresponding ink amount. The dots are recorded.

  Unlike the conventional example shown in FIG. 8, the ink area contributing to color development can be increased and the ink running cost can be reduced by using many small dots even after the large dots have started to be used. Can be planned.

Processing for switching distribution of large and small dots for each color of C (cyan) and M (magenta) Here, the reduction of ink running costs in a broad sense and a narrow sense is examined using the large and small dot distribution method described above.

  For example, if it is determined that the remaining amount of M ink is less than that of C ink, if many small dots are used for the M ink recording portion and many large dots are used for the C ink recording portion, then M The amount of ink used can be reduced and the amount of C ink used can be increased.

  FIG. 14 is a diagram showing a part of a color separation table used for switching the distribution of large and small dots for each color of C (cyan) and M (magenta). 14A shows a part of the color separation table for C ink from white to cyan, and FIG. 14B shows a part of the color separation table for M ink from white to magenta.

  As can be seen from FIG. 14A, there is no problem even if the amount of ink used increases for C ink with a large remaining amount. Therefore, in white → cyan, the amount of small dots used in the region from intermediate density to cyan is suppressed, Increases robustness. On the other hand, as shown in FIG. 14B, for the M ink with a small remaining amount, the ink consumption is more important than the robustness, and the ink of small dots in the region from white to magenta from the intermediate density to magenta. The amount used is kept at a recordable maximum value, and the M ink consumption is suppressed.

  In this way, by switching the use ratio of large and small dots according to the remaining amount of ink, it is possible to make the ink consumption uniform for each color and to suppress the ink running cost in a broad sense.

  Conversely, when it is determined that the remaining amount of C ink is smaller than that of M ink, the reverse setting shown in FIG. 14 in which cyan and magenta are replaced can be applied.

  In this way, by changing the usage ratio of large and small dots according to the remaining amount of ink, the consumption of ink with a small remaining amount of ink is suppressed, and the consumption of other inks is relatively increased, so that both inks The amount of consumption can be made uniform.

  In the above-described example, according to the remaining amounts of C ink and M ink, in order to increase the consumption amount of C ink, the ink amount of c small dots is decreased, and in order to further reduce the consumption amount of M ink, m Increased the amount of ink in small dots. However, the present invention is not limited to this, and only one of the C ink and the M ink may be changed.

  For example, the consumption amount of C ink may be increased by decreasing the small c dot and increasing the usage amount of the large C dot. In this case, the ink consumption is not reduced, but the ink consumption can be made uniform. That is, the ink running cost in a narrow sense is not reduced, but the ink running cost in a broad sense can be reduced. In this case, the robustness of white → cyan can be improved at the same time.

  Alternatively, by increasing the usage amount of m small dots and decreasing the usage amount of M large dots, it is possible to achieve uniform ink consumption while reducing ink consumption. In this case, the robustness in the white → magenta region is allowed to some extent, and reduction of ink consumption is emphasized.

  Furthermore, it can be controlled in a plurality of stages according to the remaining amount of ink.

  As described above, according to this embodiment, by changing the usage ratio of large and small dots for each ink color in accordance with the ink remaining amount, the influence on the density and color of the recorded image is minimized, and a good image quality is achieved. Can be maintained. When it is desired to eliminate the influence on the image quality by such processing, the ink amount adjustment switch of the control panel 620 is turned off, the same instruction is given from the host device, or the high image quality recording mode is selected. And good. As a result, a high-quality recorded image can be obtained without being affected by the remaining amount of ink.

  In the above description, only a single color has been described. However, since three to four colors of ink are used in color recording, there are dot sizes of large dots and small dots for each ink color, and ink consumption as described above. This control is performed for each color to be used.

  Further, black can be reproduced by mixing other inks, for example, three colors of cyan, magenta, and yellow. For this reason, when the remaining amount of black ink is smaller than the remaining amount of ink of other colors, it is possible to reproduce the black region by mixing colors of other colors and to suppress the consumption of black ink. It goes without saying that such CMY → K switching and large / small dot distribution ratio switching can be used in combination at the same time.

  In the first embodiment, based on the result of detection of the remaining amount of ink, a large to small ratio change for suppressing the consumption of ink with a small remaining amount and a small to large for promoting consumption of ink with a large remaining amount are performed. The case where the change in size ratio is always used together has been described. Here, another example of the ink remaining amount detection, the detection result determination method, and the subsequent size ratio changing method will be described.

-An example of always changing the large / small ratio to reduce the consumption of ink with a small remaining amount and the small → large / small ratio to always promote the consumption of ink with a large remaining amount An example of always changing the small to large size ratio for promoting ink consumption will be described with reference to the flowchart shown in FIG. The process at each step shown in FIG. 15 is the same as the process of FIG. 7 described in the first embodiment. Therefore, the same process is denoted by the same step reference number, and the description thereof is omitted. Only the determination and processing flow characteristic of this embodiment will be described.

  Here, the process proceeds from step S20 to step S30, and when the process further proceeds to step S40, the process always performs step S60 (large dot determination) regardless of the determination result of step S40 (small dot determination). I am doing so.

  Thus, unless an error occurs, the small to large ratio change is executed, the consumption of ink with a large remaining amount is promoted, and the ink consumption is further equalized.

-Example of changing only the ratio of large to small to reduce ink consumption for ink with low remaining amount Ink with low remaining amount is not promoted, but only ink consumption suppression for ink with low remaining amount is performed An example of performing will be described with reference to a flowchart shown in FIG. In addition, since all the processes in each step shown in FIG. 16 are included in the process of FIG. 7 described in the first embodiment, the same process is denoted by the same step reference number, and the description thereof is omitted. Only the determination and processing flow characteristic of this embodiment will be described.

  Here, the process proceeds from step S20 to step S30, and when the process further proceeds to step S40, the determination result in step S40 (small dot determination) indicates that the large to small ratio change for suppressing ink consumption is not executed. If it is possible, the process proceeds to step S80. Then, an error display is executed and the process is terminated. On the other hand, when it is determined in the small dot determination that the change in the size ratio can be performed, the process of step S50 is executed, and then the process ends.

  Accordingly, it is difficult to equalize ink consumption, but ink consumption itself can be suppressed.

・ Example of changing only the small / large ratio for promoting ink consumption for ink with a large remaining amount For small ink, the small / large ratio is not changed for promoting ink consumption without changing the large / small ratio. An example in which only the magnitude ratio change is described with reference to the flowchart shown in FIG. In addition, since all the processes in each step shown in FIG. 17 are included in the process of FIG. 7 described in the first embodiment, the same process is denoted by the same step reference number, and the description thereof is omitted. Only the determination and processing flow characteristic of this embodiment will be described.

  Here, the process proceeds from step S20 to step S30, and if there is ink whose remaining amount is equal to or less than the specified value, the process proceeds to step S60 to execute large dot determination. If it is determined that the small to large ratio change for promoting ink consumption cannot be performed, the process proceeds to step S80, an error display is executed, and then the process ends. On the other hand, when it is determined that the small to large ratio change is feasible, the process of step S70 is executed, and then the process ends.

  Accordingly, for example, the remaining amount of ink at the time of disposal after using the integrated head cartridge can be reduced.

  In this embodiment, the size ratio changing process is performed for the ink whose remaining ink amount is below the specified value. However, the remaining amount of each ink is always checked, and the remaining amount is the least. However, the magnitude ratio may always be adjusted. In this way, it is possible to always equalize the remaining amount of ink from the head cartridge use start stage.

  In this embodiment, the size ratio is changed once for the ink whose remaining amount is small. However, the change of the size ratio is not limited to one time. Accordingly, the adjustment may be performed in a plurality of times. In this way, finer control of the remaining amount of ink becomes possible.

  In the first embodiment, the ink remaining amount sensor 17 detects the ink remaining amount, and the color separation table is dynamically switched according to the detection result, thereby reducing the ink running cost in a broad sense and a narrow sense. However, here, instead of dynamically changing the usage ratio of large and small dots according to the detection result of the remaining amount of ink, for the color region that is known to have a large amount of ink consumption in advance, the ink is used more than before. An example of setting a color separation table that reduces consumption will be described.

  Generally, primary colors (colors that can be developed with one type of ink, such as Y, M, and C) consume less ink, but secondary colors (colors that are formed by mixing two types of ink, such as R (red) ), B (blue), G (green)) consumes about twice as much ink as the primary color. On the other hand, there is no great difference in the ratio between the primary color and the secondary color that appear in the input image data to the printer.

  Therefore, if a color separation table is set in advance so that the amount of ink consumed between the primary color area and the secondary color area that do not differ greatly in the image, the ink running costs in a broad sense and narrow sense can be reduced. Can be suppressed.

  FIG. 18 is a diagram showing a part of a color separation table used for processing for switching the distribution of large and small dots according to the primary color (C) and secondary color (B: blue). 18A shows a part of the color separation table for C ink from white to cyan, and FIG. 18B shows a part of the color separation table for C ink and M ink from white to blue. ing. Note that FIG. 18A and FIG. 14A are the same.

  As shown in FIG. 18A, in the white-to-cyan color separation, the primary color consumes less ink and thus improves the robustness. On the other hand, color separation is performed in such a way that large dots are mainly used in a cyan region from an intermediate density of white → cyan that increases ink consumption, and small dots are not used much.

  On the other hand, as shown in FIG. 18B, in the separation of white to blue, which is a secondary color that originally has a large amount of ink consumption, in order to suppress ink consumption, from the intermediate density of white to blue to blue. The amount of ink used for recording small dots with recordable C and M inks is kept at the maximum value. On the other hand, color separation is performed so as to suppress the amount used for large dot recording with C and M inks.

  As described above, according to this embodiment, a color separation table that brings ink consumption closer between the primary color area and the secondary color area is set in advance, so that comparison is possible regardless of the input image. Ink can be consumed while keeping the consumption evenly. Thereby, the ink running cost can be reduced.

  In the first and third embodiments, the case where the ink running cost is reduced by adjusting the use ratio of large and small dots in one printing mode has been described. Here, an ink saving mode is provided in advance in the recording mode, and in this mode, a flowchart is shown for processing for preallocating a color separation table in which the use ratio of small dots is higher than in other modes, that is, the ink consumption is reduced. The description will be given with reference.

  FIG. 19 is a flowchart showing processing for changing the size ratio at the time of color separation according to the mode setting.

  First, in step S110, the user selects a mode. This selection may be performed by pressing a switch on the control panel 620 or by a user instruction from the host device.

  Next, in step S120, it is checked whether or not the mode selected by the user is the ink saving mode. If it is determined that the ink saving mode is selected, the process proceeds to S130, and color separation processing with a high small dot ratio is executed.

  On the other hand, if it is determined that a mode other than the ink saving mode (normal mode) is selected, the process proceeds to step S140, and normal color separation processing as described in the first and third embodiments is performed. Executed. Each color separation process here is characterized by a color separation table used in each color separation process.

  FIG. 20 is a diagram for explaining a color separation table that varies depending on the mode setting.

  20A is a diagram for explaining white → cyan color separation in the normal mode, which is the same as FIG. 14A and FIG. 18A. On the other hand, FIG. 20B is a diagram for explaining the white → cyan color separation in the ink saving mode.

  In the normal mode, as can be seen from FIG. 20 (A), an emphasis is placed on robustness rather than ink consumption, and a large dot is mainly used from an intermediate density of white to cyan to cyan, and a small dot is not used much. I'm taking it. On the other hand, in the ink saving mode, as shown in FIG. 20B, the ink consumption is emphasized rather than the robustness. That is, color separation is performed so as to keep the ink usage by small dot recording from the white to cyan intermediate density to cyan at the maximum recordable value, while suppressing the ink usage by large dot recording.

  Therefore, according to the embodiment described above, when recording is performed in the ink saving mode by user selection, the ink usage amount by small dot recording can be increased and the ink usage amount by large dot recording can be suppressed. . Thereby, the amount of ink used is suppressed.

  In the embodiment described above, an example using four YMCK inks contained in four ink tanks has been described. However, the number of similar color inks is not limited to one. For example, in the case of a system that uses dark and light inks of similar colors and records with large and small dots, light ink can be recorded only with large dots, and dark ink can be recorded with large and small dots. Even in such a case, it is apparent that the present invention can be applied by paying attention to the ratio change control of the large and small dots of dark ink.

  In order to apply the present invention, it suffices if there is an ink color that can record at least one set of different dot sizes, and there is no need for a system in which large and small dots exist for all colors of CMYK. For example, the present invention is also applied to a system that records large and small dots only when C and M inks are used, such as C (large dots) c (small dots) M (large dots) m (small dots) YK. can do.

  In the example described above, a combination of two large and small dot sizes has been described. However, the present invention can be applied to any combination as long as there are two or more dot sizes. Ink consumption can be reduced by prioritizing recording with smaller sized dots instead of larger sized dots.

  According to the present invention, the method of reducing the ink consumption by increasing the small dots while decreasing the large dots is based on whether the large / small dot ratio is dynamically changed regardless of whether or not the ink remaining amount is detected. It can be applied regardless of whether it is performed statically.

  In the above embodiments, the liquid droplets ejected from the recording head have been described as ink, and the liquid stored in the ink tank has been described as ink. However, the storage is limited to ink. It is not a thing. For example, a treatment liquid discharged to the recording medium may be accommodated in the ink tank in order to improve the fixability and water resistance of the recorded image or to improve the image quality.

  The above embodiment uses a method that includes means (for example, an electrothermal converter) for generating thermal energy for ink ejection, and causes a change in the state of the ink by the thermal energy, among ink jet recording methods. High density and high definition of recording can be achieved.

  In addition, the ink jet recording apparatus according to the present invention may be used as an image output apparatus for information processing equipment such as a computer, a copying apparatus combined with a reader, or a facsimile apparatus having a transmission / reception function. It may be one taken.

1 is an external perspective view showing an outline of a configuration of an ink jet printer that is a typical embodiment of the present invention. 2 is an external perspective view showing a configuration of a head cartridge IJC in which an ink tank and a recording head are integrally formed. FIG. It is a figure which shows the internal structure of the head cartridge IJC. It is a figure which shows the internal structure of an independent type head cartridge. It is a block diagram which shows the control structure of the inkjet printer shown in FIG. It is a figure which shows the content of the image process which MPU601 and ASIC603 perform. It is a flowchart which shows the process which changes a large / small dot ratio according to the result of ink remaining amount detection. FIG. 6 is a diagram for explaining large and small dot distribution by a color separation table 20 used in color separation conversion processing 22. It is a figure which shows the color separation table comprised by a three-dimensional LUT. FIG. 5 is a schematic diagram showing a state immediately after a large dot droplet and a small dot droplet are attached to the surface of a recording medium. It is a figure which shows the recording state of a large dot. It is a figure which shows the recording state of a small dot. It is a figure which shows a part of color separation table which prescribes | regulates the distribution of the large and small dots in white-> cyan. It is a figure which shows a part of color separation table used for the process which switches distribution of a large and small dot according to the color of C (cyan) and M (magenta). It is a flowchart showing a process of always changing a small to large size ratio to promote ink consumption regardless of whether the large to small size ratio is changed for suppressing ink consumption. FIG. 10 is a flowchart showing a process of merely suppressing ink consumption of ink with a small remaining amount without performing ink consumption promotion for ink with a large remaining amount. FIG. It is a flowchart showing a process for changing only the small to large size ratio for promoting ink consumption without changing the size ratio for ink with a small remaining amount. It is a figure which shows a part of color separation table used for the process which switches distribution of a large and small dot for the color of a primary color (C) and a secondary color (B: blue). It is a flowchart which shows the process which changes the magnitude ratio at the time of color separation according to mode setting. It is a figure explaining the color separation table which changes with every mode setting.

Explanation of symbols

HC Carriage IJC Head cartridge IJH Recording head IJRA Inkjet recording device 17 Ink remaining amount sensor 20 Color separation table 21 Resolution conversion processing 22 Color separation conversion processing 23 Halftone processing 24 Interlace processing 600 Controller 601 MPU
602 ROM
603 ASIC
604 RAM
605 System bus 610 Host device 611 Interface 620 Control panel 644 Head driver

Claims (6)

An image is formed by applying a first ink droplet and a second ink droplet having a size larger than the first ink droplet from a recording head to a recording medium in communication with an ink tank containing ink of a predetermined color. A data generation method for generating recording data for forming,
For a signal value corresponding to recording data for forming the image, a first application amount for applying the first ink droplet to a unit area of the recording medium, and a second ink droplet A first setting step for determining a second amount to be given;
For the signal value corresponding to the recording data for forming the image, there is a third amount that is an application amount for applying the first ink droplet to the unit area and is larger than the first application amount. A second setting step for determining an application amount and a fourth application amount that is an application amount for applying the second ink droplet and is smaller than the second application amount;
Recording data for applying the first ink droplet and recording data for applying the second ink droplet by selecting one of the first setting step and the second setting step And a generating step for generating
When the signal value is within a predetermined range, the sum of the third amount and the fourth amount determined in the second setting step is the first amount determined in the first setting step. A data generation method characterized in that the amount is less than the sum of the first grant amount and the second grant amount. A detection step of detecting the remaining amount of the ink tank;
The generation step selects the first step when the remaining amount detected in the detection step is equal to or greater than a predetermined value, and the second setting step when the remaining amount is less than the predetermined value. The data generation method according to claim 1, wherein: is selected. The data generation method according to claim 1, wherein the generation step selects either the first setting step or the second setting step based on an instruction from a user. 4. The recording head according to claim 1, further comprising: a first ejection port that ejects the first ink droplet; and a second ejection port that ejects the second ink droplet. The data generation method according to item 1. As the signal value increases in the predetermined range, the third application amount determined in the second setting step is constant, but the fourth application amount determined in the second setting step. 5. The data generation method according to claim 1, wherein the number increases. An image is formed by applying a first ink droplet and a second ink droplet having a size larger than the first ink droplet from a recording head to a recording medium in communication with an ink tank containing ink of a predetermined color. A data generation device for generating recording data for forming,
For a signal value corresponding to recording data for forming the image, a first application amount for applying the first ink droplet to a unit area of the recording medium, and a second ink droplet A first setting means for determining a second grant amount for granting;
For the signal value corresponding to the recording data for forming the image, there is a third amount that is an application amount for applying the first ink droplet to the unit area and is larger than the first application amount. A second setting means for determining an application amount and a fourth application amount that is an application amount for applying the second ink droplet and is smaller than the second application amount;
Recording data for applying the first ink droplet and recording data for applying the second ink droplet by selecting one of the first setting device and the second setting device; Generating means for generating
When the signal value is within a predetermined range, the sum of the third amount to be given and the fourth amount to be given determined by the second setting means is the first value determined by the first setting means. A data generation device characterized in that the data generation device is smaller than the sum of the first grant amount and the second grant amount.

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