INK-JET RECORDING DEVICE, IMAGE-PROCESSING DEVICE, AND IMAGE PROCESSING METHOD

Information

  • Patent Application
  • 20070242096
  • Publication Number
    20070242096
  • Date Filed
    April 09, 2007
    17 years ago
  • Date Published
    October 18, 2007
    16 years ago
Abstract
Color processing is performed for each image data, so as to switch generating methods for black data to perform appropriate sharpness processing regarding image data wherein sharpness of printing results is important and image data wherein gradation of the image is important. A recording device is provided, wherein by performing such processing, black images such as characters or lines maintain sharpness or clarity, and picture images can be formed as high quality images.
Description

BRIEF DESCRIPTION OF THE DRAWINGS


FIG. 1 is a block diagram illustrating an example of a configuration of a recording system according to an embodiment of the present invention.



FIG. 2 is a perspective view illustrating an example of the mechanisms of the primary portions of a printer 200 according to an embodiment of the present invention.



FIG. 3 is a block view illustrating an example of the hardware configuration of the printer 200 according to an embodiment of the present invention.



FIGS. 4A through 4D are diagrams describing a conventional example.



FIG. 5 is a flowchart diagram of color conversion processing.



FIGS. 6A and 6B are diagrams illustrating a conversion table used for color conversion processing.



FIGS. 7A and 7B are diagrams illustrating a picture image with application of an embodiment of the present invention.



FIG. 8 is a block diagram describing the flow of detection of black-dot proximity pixels, detection of color-dot proximity pixels, generation of data with color dots provided, generation of reduced black image data, and generation of printing data.



FIG. 9 is a flowchart diagram of detection processing of pixels for color dots imparted for prevention of smearing.



FIGS. 10A through 10C are diagrams of a detection example of pixels for color dots imparted for prevention of smearing.



FIG. 11 is a flowchart diagram of detection processing of pixels for color dots imparted for prevention of bleeding between black and color.



FIGS. 12A through 12D are diagrams of a detection example of pixels for color dots imparted for prevention of bleeding.



FIGS. 13A through 13C are diagrams of a detection example of black dot non-proximity pixels.



FIGS. 14A through 14G are diagrams of an example of generating data for color dots imparted for prevention of smearing.



FIGS. 15A through 15G are diagrams of an example of generating data for color dots imparted for prevention of bleeding.



FIGS. 16A through 16C are diagrams of an example of generating Bk non-edge reduction data of black-dot non-proximity pixels.



FIG. 17 is a flowchart diagram of generation processing of printing color data.



FIG. 18 is a flowchart diagram of generation processing of printing black data.





DESCRIPTION OF THE EMBODIMENTS

The embodiments of the present invention will be described in detail below with reference to the drawings.


First Embodiment


FIG. 1 is a block diagram illustrating a configuration of a recording system according to an embodiment of the present invention. In the diagram, a host 100 serving as an information-processing apparatus is an apparatus such as a personal computer or digital camera, which is connected to a printer (recording device) 200. This host 100 has an interface 14 for communicating between a printer 200 and a CPU 10, memory 11, external storing unit 13, and input unit 12 such as a keyboard or mouse. The CPU 10 executes various processing according to the programs stored in the memory 11, and particularly executes color processing, image processing such as quantization processing or the like, and further executes recording properties correction processing relating to the present embodiment. These programs are stored in the external storing unit 13, or are supplied from an externally connected unit. The host 100 is connected with a printer 200 serving as a recording device via the interface, and can perform recording by transmitting the recording data that has been subjected to image processing to the printer 200. Also, a user may execute the program (application) stored in the memory 11 to create image data or recording data which are output from the printer.


Printer Configuration


FIG. 2 is a schematic perspective view illustrating a mechanical configuration of the printer 200. In FIG. 2, reference numeral 1 denotes a recording medium such as a sheet of paper or a plastic sheet, several sheets of which are stacked in the recording-medium loading unit such as a cassette or the like. During recording, the sheets are separated one at a time by a supply roller (not shown) provided on the recording-medium loading unit, and supplied. The supplied recording media are disposed with a fixed spacing therebetween, and are transported by a predetermined amount in the arrow A direction in the diagram, at a timing according to scanning of the recording head, by a first conveyance roller pair 3 and a second conveyance roller pair 4 which are each driven by separate motors (not shown).


Reference numeral 5 denotes a recording head of an ink-jet method for discharging ink onto a recording medium 1 to perform recording. An ink tank is provided on the recording head 5 in FIG. 2 so as to be integrated with the recording head 5, and the ink stored in the ink tank is supplied to the recording head. Also, the recording head 5 is driven according to a discharge signal according to the recording data, thereby discharging ink from an ink nozzle provided on the recording head. More specifically, an electrothermal transducer is provided at the ink flow path corresponding to each ink nozzle arrayed on the recording head, and using the heat energy generated by this electrothermal transducer, air bubbles are generated in the ink, and the ink is discharged by the pressure of the air bubbles. The recording head 5 and ink cartridges are mounted on a carriage 6. Driving force of a carriage motor 23 is transmitted to the carriage 6 via a belt 7 and pulleys 8a and 8b, thereby enabling back and forth movement of the carriage 6 along a guide shaft 9, and enabling scanning of the recording head.


With the above configuration, the recording head 5 can discharge the ink onto the recording medium 1 according to a discharge signal while scanning in the direction of the arrow B in the diagram (the main scanning direction) so as to form ink dots on the sheet 1 and thus perform recording. The recording head 5 is moved to a home position as necessary, and by performing recovery operations by a discharge recovery device, recovers from discharge malfunctions such as non-discharge due to a clogged nozzle, shifting of the landing positions of the discharged ink drops, and so forth. When the transporting roller pair 3, 4 are driven to synchronize with the recording scanning in the main scanning direction of the recording head 5, the recording medium 1 is transported a predetermined amount (for example, one line worth) in the arrow A direction (sub scanning direction). By repeating the recording scanning in the main scanning direction of the recording head, and the transporting operation in the sub scanning direction of the recording medium, recording an image or the like onto a recording medium 1 can be performed.



FIG. 3 is a block diagram showing a control configuration of the printer 200. As shown in FIG. 3, the control unit 20 has a CPU 20a such as a microprocessor or the like, and a ROM 20c storing a control program of the CPU 20a or various data therewithin. Further, the control unit 20 is used as a work area for the CPU 20a, and also has a RAM 20b for performing storage or the like of various data such as recording data or adjustment values or the like. The recording data which is transmitted from the host 100 connected to the printer 200, and received via the interface 21, is stored in the RAM 20b. Further, the printer 200 has an interface 21, operating panel 22, and drivers 27 and 28. The driver 27 drives each motor (a motor 23 for driving the carriage, a motor 24 for driving the paper supply roller, a motor 25 for driving the first transporting roller pair, and a motor 26 for driving the second transporting roller pair), and the driver 28 drives the recording head 5.


With the above configuration, the control unit 20 performs processing for data input/output such as recording data between the host 100 via the interface 21, and processing for inputting various information (for example, character pitch, character type, and so forth) from the operating panel 22. Also, the control unit 20 outputs an ON/OFF signal for driving the motors 23 through 26 via the interface 21, and also outputs the discharge signal or the like to the driver 28, to control ink discharge driving at the recording head.


Next, a recording data generating method will be described, starting with a color conversion method according to the present embodiment.


Color Conversion Processing


FIG. 5 is a flowchart of the color converting process according to the present embodiment. When the user gives recording instructions from the program (application) of the host 100 connected to the printer 200, the printer driver installed on the host 100 determines object attributes of the image data (S900). Specifically, the printer driver determines whether the object attributes in a predetermined region of the image data generated with the program (application) is a picture image or a character/line-drawing image. The object attributes are imparted at the time of the image data being generated with the program (application), and the way in which the object attributes are imparted differs from one program to another.


For example, the object attributes are imparted so as to indicate whether the image data in a predetermined region of the image data is picture image data or character image data or line-drawing image data. Also, as another example, the image data may be divided into a character layer, a picture image layer, and a line-drawing image layer, and object attributes of the image data are imparted from the region containing the image data, and the from the layers. Further, an individual object attribute may be imparted by the operating system based on the object attributes imparted by the application. Note that the printer driver can determine the object attributes of a predetermined region of image data generated with the program, by analyzing the image data.


Also, the printer driver can determine object attributes based on drawing commands of operating system or application. Note that the image data generated with the program includes picture images (photograph images), characters, and line drawings. Further, not only files generated by the user with the program, but also data recorded from the printer 200 such as a Web screen displayed via a network or a photograph image captured by a camera can also serve as image data. Picture image data refers to image data such as photographs or pictorial art. Line drawings refer to graphic images drawn with lines, such as outlines, geometric shapes, or CAD drawings.


In step S900, if the object attributes are determined to be a picture image, color conversion processing from RGB to CMYK is performed, using the conversion table (LUT) for picture images in FIG. 6B. Also, in S900, if the object attributes are determined to be a character/line drawing image, color conversion processing is performed using the conversion table for character/line drawing images in FIG. 6A. FIG. 6A shows an example of a grayline conversion table (LUT) used in the event of performing color conversion processing. The horizontal axis of the conversion table shows the color displayed with the RGB of the image data, and moving farther left (the closer to R=255, G=255, B=255) indicates more white, and moving farther right (R=0, G=0, B=0) indicates more black. Also, the vertical axis shows the color displayed with CMYK of the image data. Color conversion processing obtains the respective values of CMYK as output values, which correspond to the respective RGB of the image data serving as the input values. For example, as shown in FIG. 6A, when an 8-bit signal value R=G=B=0 (the color of the image data is black) is the input value, this is converted to an output value showing as C=0, M=0, Y=0, K=255. Note that in FIGS. 6A and 6B, the conversion table of a graph format is used for the RGB→CMYK for the conversion processing, but a conversion table in which the corresponding values have been compiled in a chart format may also be used. Further, FIGS. 6A and 6B show the conversion table in two dimensions, but it is possible to use a table shown in three dimensions.


In FIGS. 6A and 6B, the conversion curves for CMY are the same, but the K conversion line differs. With FIG. 6A which is the conversion table for character/line drawings, the value of K is converted to the maximum value of 255 when the black portion of the image data expressed with RGB is converted to CMYK. On the other hand, with FIG. 6B which is the conversion table for picture images, the value of K is converted to 255×0.8≈204 which is a value of approximately 80% of the maximum value of 255, when converting the black portion of the image data represented in RGB into CMYK. With the conversion table for picture images, by setting the maximum value of the K conversion curve to be lower than the K conversion curve for character/line drawings, the black density can by lowered in the event of recording picture images. Note that with FIGS. 6A and 6B, the same CMY conversion curves are used, but a conversion table with different conversion curves may be used.


Next, binary processing is performed (S903) as to the CMYK output value converted in S901 and S902. By performing binary processing, recording data can be generated which shows whether or not ink drops are to be discharged from the recording head, corresponding to the position of the recording head as to the recording medium. Note that following RGB→CMYK conversion of the picture image shown in FIG. 4A using the conversion table in FIG. 6A, the recording data when performing binary processing becomes the same as in FIG. 4A. However, following RGB→CMYK conversion of the picture image in FIG. 4A using the conversion table in FIG. 6B, the recording data when performing binary processing becomes the same as in FIG. 7A. This is because the black conversion curve in the conversion table in FIG. 6B is set to have a low black density. Since the conversion curve is such that the black density becomes low, recording data is generated wherein blank dots are increased compared to the original picture image in FIG. 4A. Based on the recording data in FIG. 7A, processing to decrease the smearing/border bleeding to be described later (processing such as imparting color dots or reducing black dots, or the like) is performed, and the pictured image data thus generated is shown in FIG. 7B. The black dots surrounding the blank dots in FIG. 7A are all determined to be an edge portion of a region wherein black is discharged, and therefore the picture image data in FIG. 7B is not subjected to imparting of color ink or reduction of black ink for smearing reduction. Consequently, a picture image can be output without deteriorating the gradient thereof.


Thus, in the event of subjecting the image data to RGB→CMYK conversion, by setting the individual conversion tables for the different objects, black images such as characters or line drawings can retain the sharpness and clearness thereof, and picture images can be formed as high-quality images. At this time, the conversion table of an object wherein the black image such as characters or line drawings is desired to be expressed clearly is set so that an edge portion and a non-edge portion of the black image exist. Further, the conversion table of an object wherein reduction of lower recording quality due to deteriorated gradients is desired as with a picture image is configured only with the edge portions of the black image, and is set such that non-edge portions do not exist. Thus, the black image is clearly recorded with the edge portions of the black image, and the occurrence of smearing is reduced with the non-edge portions of the black image. Note that with the edge portions of the black image, in the event that this is adjacent to a region wherein color ink is imparted, the processing for decreasing border bleeding is given preference, and so color ink may be imparted.


Also, with the above description, with an object such as a character or line drawing, the configuration is such that the black dots at the non-edge portions are reduced, but a high recording density of characters or line drawings can be realized without reducing the black dots.


Further, with the above description, the configuration is such that the color conversion table for characters or line drawings differ from the color conversion table of a picture image, but the color conversion tables used for character images and line drawing images may also be arranged to be different.



FIG. 8 shows a block diagram describing the flow for printing data generation for performing processing to reduce smearing/border bleeding, based on the recording data subjected to binary processing. With FIG. 8, printing data is generated by performing detection of black-dot proximity pixels, detection of color-dot proximity pixels, generation of color-dot imparting data, and generation of black reduction image data. Note that the detailed descriptions relating to each of these will be described later.


First, of the recording data subjected to binary processing, black regions needing color dots to be imparted are detected in order to decrease the occurrence of smearing at the regions wherein black ink is discharged. Therefore, using the K (Bk) recording data (original Bk data D1000) is used to detect whether or not there are many pixels discharging black ink in the proximity of predetermined black pixels. This process is called black-dot proximity pixel detection processing (E1000). Next, data is generated (black-dot proximity pixel data D1001) for a region wherein there are many pixels discharging black ink.


Next, using OR data (D1008) of original C, M, Y having taken the logical sum of the original C data (D1005), original M data (D1006), original Y data (D1007), and original Bk data (D1000), detection processing (E1004) of color-dot proximity pixels to which color dots are to be imparted in order to prevent border bleeding, and thus color-dot proximity pixel data (D1009) is generated.


By using the black-dot proximity pixel data (D1001) and original Bk data (D1000) to perform detection processing (E1008) of the black-dot non-proximity pixels, black-dot non-proximity pixel data (D1017) is generated.


By taking the logical product of a Bk reduction mask (E1009) as to the black-dot proximity pixel data (D1001), Bk non-edge reduction data (D1018) is generated.


By taking the logical product of C mask 1 (E1001), M mask 1 (E1002), and Y mask 1 (E1003) as to the black-dot proximity pixel data (D1001), the C-imparted data 1 (D1002), M-imparted data 1 (D1003), and Y-imparted data 1 (D1004) is generated.


By taking the logical product of C mask 2 (E1005), M mask 2 (E1006), and Y mask 2 (E1007) as to the color-dot proximity pixel data (D1009), the C-imparted data 2 (D1001), M-imparted data 2 (D1011), and Y-imparted data 2 (D1012) is generated.


By taking the logical sum of the black-dot non-proximity image data (D1017) and the Bk non-edge reduction data (D1018), the printing Bk data (D1016) is generated.


By taking the logical sum of the original C data (D1005) and the C-imparted data 1 (D1002) and the C-imparted data 2 (D1010), the printing C data (D 1013) is generated. By performing similar processing, the printing M data (D1014) and printing Y data (D1015) is generated. Using the printing data for each of the colors, an image is formed by the printer.


Detection Processing of Pixels for Color-Dot Imparting

Detection of Black-Dot Proximity Pixels for Smearing Prevention



FIG. 9 is a flowchart of the detection processing of black-dot proximity pixels for smearing prevention. Determination is made as to whether black dots exist on the pixel of interest, and whether the total number of black dots existing within the 3×3 matrix is 9 (S101). In the event the total number of black dots is 9, the bit for the pixel of interest is turned ON (S102). If not, the bit for the pixel of interest is turned OFF (S103). Subsequently, the pixel of interest is shifted (S104). If all of the data has finished, this serves as the end (S105), and otherwise the above processing is repeated. Here, the threshold of the total number of black dots is set to be 9, but an optimal value should be used to match the features of the ink or the features of the recording device.



FIGS. 10A through 10C are diagrams showing an example of black-dot proximity pixels detecting. FIG. 10A shows a 3×3 matrix with the pixel of interest at the center thereof. FIG. 10B is a black original image. Processing is performed as to the black original data while shifting the 3×3 matrix one pixel at a time in order. If the bit for the pixel of interest is turned ON in the event that the total number of black dots within the matrix is 9, a black-dot proximity pixel for smearing prevention can be detected, as shown in FIG. 10C.


As can be clearly understood from FIG. 10C, with this processing, only a region wherein comparative duty of black is high can be detected. The edge regions wherein comparative duty is low is not detected, and therefore color dots are not imparted, thus maintaining sharpness of the black image.


Detecting of Color-Dot Proximity Pixels for Bleeding Prevention


FIG. 11 is a flowchart showing detection processing of color-dot proximity pixels for bleeding prevention of black and color.


Determination is made as to whether black dots exist on the pixel of interest, and whether the total number of color dots existing within the 3×3 matrix is 1 or more (S201). In the event the total number of color dots is 1 or more, the bit for the pixel of interest is turned ON (S202). If not, the bit for the pixel of interest is turned OFF (S203). Subsequently, the pixel of interest is shifted (S204). If all of the data has finished, this serves as the end (S205), and otherwise the above processing is repeated. Here, the threshold of the total number of color dots is set to be 1, but an optimal value should be used to match the features of the ink or the features of the recording device.



FIGS. 12A through 12D are diagrams showing an example of color-dot proximity pixels detecting for bleeding prevention. FIG. 12A shows a 3×3 matrix with the pixel of interest at the center thereof. FIG. 12B is a black original image, and FIG. 12C is a color original image. Processing is performed for each black pixel of the black original data with respect to the color original data while shifting the 3×3 matrix one pixel at a time in order. The bit for the pixel of interest is turned ON in the event that the total number of color dots within the matrix is 1 or more. In this way color-dot proximity pixel for bleeding prevention can be detected, as shown in FIG. 12D.


As can be clearly understood from FIG. 12D, with this processing, only a border region of black and color can be detected. By imparting color dots at the border region, border bleeding can be prevented. Generating of black-dot non-proximity pixels (Bk edge unit)



FIGS. 13A through 13C show a detection example of black-dot non-proximity pixels. FIG. 13B shows the black-dot proximity pixel (Bk solid portion) data, and FIG. 13A shows the original black data. By taking the logical product of the inverse data of the black-dot proximity pixel data (Bk solid portion) and the original black data, the black-dot non-proximity pixel (Bk edge portion) data shown in FIG. 13C can be generated.


Generating of Color Dot-Imparted Data

Generating of Color Dot-Imparted Data for Smearing Prevention



FIGS. 14A through 14G show an example of generating color dot-imparted data for smearing prevention. FIG. 14A shows black-dot proximity pixel data. FIGS. 14B through 14D show the mask 1 for cyan, magenta, and yellow for generating a predetermined amount of imparted data. Let us say that the ratio of imparted data amount for each color is 18% cyan, 6% magenta, and 5% yellow. By taking the logical product of the black-dot proximity pixel data and the mask 1 of each color, the imparted data for each color shown in FIGS. 14E through 14G is generated. Here, the imparted data amount and the mask size for each color should be taken as an appropriate value according to the ink features or the configuration of the recording device. Also, the way in which the dots are arrayed within the mask may have regularity, or may be pseudo-random.


Generating Color Dot-Imparted Data for Bleeding Prevention


FIG. 9 shows an example of generating color dot-imparted data for bleeding prevention. FIG. 15A shows color-dot proximity image data. FIGS. 15B through 15D show the mask 2 for cyan, magenta, and yellow for generating a predetermined amount of imparted data. Let us say that the ratio of imparted data for each color is 30% cyan, 5% magenta, and 5% yellow. By taking the logical product of the color-dot proximity pixel data and the mask 2 of each color, the imparted data for each color shown in FIGS. 15E through 15G is generated. Here, the reason for a relatively large amount of cyan imparted data is that only cyan ink is reactive as to black ink, and a recording device with a coagulating type of ink system is assumed to be used. The imparted data amount and the mask size for each color should be taken as an appropriate value according to the ink features or the configuration of the recording device. Also, the way in which the dots are arrayed within the mask may have regularity, or may be pseudo-random.


Decimation Processing of Black-Dot Non-Proximity Image Data


FIGS. 16A through 16C show an example of black dot proximity image data. FIG. 16A shows black dot proximity image data. By taking the logical product of the black dot proximity image data and the black reduction mask shown in FIG. 16B, the Bk non-edge reduction data shown in FIG. 16C is generated.


Generating of Printing Color Data


FIG. 17 is a flowchart showing the generation process of printing color data. The black-dot proximity pixel data is detected (S301). Subsequently, by taking the logical product of the black-dot proximity pixel data and the mask 1 for cyan, magenta, and yellow, the cyan, magenta, and yellow imparted data 1 is generated (S302). Next, the color-dot proximity pixel data is detected (S303), and, by taking the logical product of the mask 2 for cyan, magenta, and yellow, the cyan, magenta, and yellow imparted data 2 is generated (S304). Finally, the logical sum of the original cyan, magenta, and yellow data and the imparted data 1 of each color and the imparted data 2 of each color is taken, and the printing cyan, magenta, and yellow data is generated (S305).


Generating of Printing Black Data


FIG. 18 is a flowchart showing the generation process of printing black data. The black-dot proximity pixel data is detected (S401). Subsequently, the black-dot non-proximity image data is detected (S402). By taking the logical product of the black-dot proximity pixel data and the Bk reduction mask, the Bk non-edge reduction data is generated (S403). Finally, the logical sum of the black dot non-proximity image data and the Bk non-edge decimation data is taken, and the printing black data is generated (S404).


As a result of the above color conversion processing, black dot proximity image data is detected in character or line-drawing images, and black dot proximity image data is not detected in picture images.


Consequently, black characters or black line printing can be improved with regard to sharpness and smearing, and recording can be performed without deterioration of gradients as to picture images.


Also, an ink-jet recording device can be provided enable optimum processing, even in the case wherein attribute information of an object is missing, in the event of detecting black pixels wherein black dots and color dots are close to each other, as in image data. At this time, optimum processing is performed on the edges and non-edges of the black image, as with an object wherein sharpness of the printing results is important, and an object wherein gradients are important. If the bit data for each of these images holds the object attribute information, determination can be made as to whether edge processing is necessary or not. In order for the various high-resolution bit data to hold the object attribute information, a large amount of memory is required, and also time is required for determining whether or not edge processing is needed. Thus, with the present embodiment, due to reasons such as image quality decreasing by performing edge processing and non-edge processing, an image is generated so that a non-edge region is not generated for an object not requiring edge processing. Consequently, there is no non-edge region, and so recording is enabled without decreasing image quality of a region for imparting black.


Note that with the present embodiment, the printer driver is configured to determine object attributes of the image data of the predetermined region, based on the object attributes imparted by the application. A configuration may be made wherein, in the event that object attributes are not imparted by the application, or in the event that object attributes imparted by the application cannot be confirmed, the printer driver determines the object attributes. Specifically, the object attributes can be determined, based on the ratio (Duty) of black ink imparted and the ratio (Duty) of color ink imparted for a predetermined region as to image data transmitted from the host computer. For example, in the case that the ratio of black ink imparted and the ratio of color ink imparted are both low, this can be determined to be character image data or line-drawing image data. Also, in the case that the ratio of black ink imparted is low but the ratio of color ink imparted is high, this can be determined to be picture data. Note that in the case that the ratio of black ink imparted is comparatively low and the ratio of color ink imparted is of a medium range, this can be determined to be line-drawing image data.


Also, with the present embodiment, in the case that the object attributes are picture images, processing has been performed so that there are not non-edge portions in the black image so that color ink is not imparted as to the region wherein black ink is imparted, but a configuration may be made wherein color ink is imparted. For example, depending on recording conditions such as recording mode or types of recording media, color ink may be imparted even if the image quality is somewhat lowered, in order to preference the improvement of black-ink fixing or the decrease of bleeding. For recording conditions wherein such improvement of black ink fixing or the decrease of bleeding is given higher priority, a condition may be given such as giving higher priority to recording speed over image quality. Such a recording condition would be a case of performing recording with comparatively few recording head scans (for example, twice), or recording performed as to a recording medium with poor ink absorption (for example, plain paper). Thus, even if the object attributes are a picture image, the black image reduction amount can be made to differ so that the color-ink imparted amount on a black image differs according to recording conditions.


Second embodiment

Here, the signal values of K, C, M, Y as to R=G B=0 is set at a table value to be converted to the following values as to a picture image. K=255×0.8≈204, C=255×0.18≈46, M=255×0.06≈15, Y=255 0.05≈13. On the other hand, for characters and line-drawing images, the table values are set to convert to K=255, C=0, M=0, Y=0.


Thus, the conversion table should be set to a table wherein appropriate values are taken according to needs such as ink composition or recording medium ink absorption, recording mode, recording speed, and so forth.


While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications, equivalent structures and functions.


This application claims the benefit of Japanese Application No. 2006-113446 filed Apr. 17, 2006 and No. 2007-061725 filed Mar. 12, 2007, which are hereby incorporated by reference herein in their entirety.

Claims
  • 1. An ink-jet recording device for printing images based on image data using a recording head, said ink-jet recording device comprising: a determining unit configured to determine object attributes of said image data;a storing unit configured to store a plurality of conversion tables for conversion from a RGB color expression to a YMCK color expression; anda color conversion unit configured to convert color using a predetermined conversion table of said plurality of conversion tables, according to the object attributes determined by said determining unit;wherein said color conversion unit is configured to differentiate between a conversion table for use in color conversion of a picture image, and a conversion table for use in color conversion of a character image.
  • 2. The ink-jet recording device according to claim 1, wherein said color conversion unit is configured to differentiate between a conversion table for use in color conversion of a picture image, and a conversion table for use in color conversion of a line drawing.
  • 3. The ink-jet recording device according to claim 1, wherein, in the case of said image data object attribute being a picture image, said color conversion unit is configured to use a conversion table wherein the black region of the picture image converted to YMCK color expression is smaller than the black region of the picture image of RGB color expression before conversion.
  • 4. The ink-jet recording device according to claim 1, further comprising: a color ink imparting unit configured to impart a predetermined amount of color ink on the non-edge portion of a region of an image using black ink, of the image data with YMCK color expression which has been converted with said color converting unit;wherein said color ink imparting unit is configured so that the amount of said imparted color ink differs according to the object attributes determined by said determining unit.
  • 5. The ink-jet recording device according to claim 4, configured to impart, with said color ink imparting unit, less color ink to the non-edge portion of a picture image than to the non-edge portion of a character image.
  • 6. The ink-jet recording device according to claim 4, configured so that in the case that the object attribute is a picture image, said color conversion unit performs color conversion using a conversion table whereby many non-edge portions are detected.
  • 7. The ink-jet recording device according to claim 1, configured so that in the case that the object attribute is a picture image, said color conversion unit performs color conversion using a conversion table whereby the density of black is lowered.
  • 8. An ink-jet recording device for printing images based on image data using a recording head which discharges black ink and color ink, said ink-jet recording device comprising: a determining unit configured to determine object attributes of said image data; andan imparting unit configured to impart color ink to, of said image data, the non-edge portion of a region is to be printed with black ink;wherein said imparting unit is configured to vary the amount of said imparted color ink to said non-edge portion according to said object attributes.
  • 9. The ink-jet recording device according to claim 8, configured to impart, with said imparting unit, less color ink to the non-edge portion of the picture image than to the non-edge portion of a character image.
  • 10. The ink-jet recording device according to claim 8, configured so that in the case that the object attribute is a picture image, said imparting unit imparts color ink to the non-edge portion of the image data wherein the black data of the image data is reduced.
  • 11. The ink-jet recording device according to claim 10, configured so that the black data of said image data is reduced so as to lessen the non-edge portions of the image data, in the event that the object attribute is picture image.
  • 12. An image-processing device for generating recording data based on image data wherein a plurality of pixels including pixels with black data and color data are arrayed, said image-processing device comprising: a determining unit configured to determine object attributes of said image data;a storing unit configured to store a plurality of conversion tables for conversion from a RGB color expression to a YMCK color expression; anda color conversion unit configured to convert color using a predetermined conversion table of said plurality of conversion tables, according to the object attributes determined by said determining unit;wherein said color conversion unit is configured to differentiate between a conversion table for use in color conversion of a picture image, and a conversion table for use in color conversion of a character image.
  • 13. An image-processing device for generating recording data based on image data wherein a plurality of pixels including pixels with black data and color ink are arrayed, said image-processing device comprising: a determining unit configured to determine object attributes of said image data;a generating unit configured to generate color data so as to add color data as to the non-edge portion of the black data region of said image data;wherein said generating unit is configured to vary the amount of said added color data according to said object attributes.
  • 14. An image processing method for generating recording data based on image data wherein a plurality of pixels including pixels with black data and color data are arrayed, said method comprising: a determining process of determining object attributes of said image data; anda color conversion process of converting color using a predetermined conversion table of a plurality of conversion tables for conversion from a RGB color expression to a YMCK color expression, according to the object attributes determined with said determining process;wherein said color conversion process differentiates between a conversion table for color conversion of a picture image, and a conversion table for color conversion of a picture image.
  • 15. The image processing method according to claim 14, wherein said color conversion process differentiates between a conversion table for use in color conversion of a picture image, and a conversion table for use in color conversion of a line drawing.
  • 16. The image processing method according to claim 14, further comprising: a generation process for detecting an edge portion and a non-edge portion of a region is to be printed with black ink, and generating color data wherein a predetermined amount of color data is added on the non-edge portion of the detected region, of the image data with YMCK color expression which has been converted with said color conversion process;wherein the amount of said added color data is differentiated according to the object attributes determined by said determining process.
  • 17. The image processing method according to claim 16, wherein, with said generation process, the amount of color data which the object attribute adds on said non-edge portion of the picture image is less than the amount of color data which the object attribute adds on said non-edge portion of a character image.
  • 18. The image processing method according to claim 16, configured so that in the case that the object attribute is a picture image, said color conversion process performs color conversion using a conversion table whereby a plurality of non-edge portions are detected.
  • 19. The image processing method according to claim 14, configured so that in the case that the object attribute is a picture image, said color conversion process performs color conversion using a conversion table whereby the density of black is lowered.
  • 20. An ink-jet recording method wherein images are formed based on image data using a recording head which is operable to discharge black ink and color ink, said method comprising: a determining process for determining object attributes of said image data; andan imparting process of imparting color ink to, of said image data, the non-edge portion of a region is to be printed with black ink;wherein said imparting process varies the amount of said imparted color ink to said non-edge portion according to said object attributes.
Priority Claims (2)
Number Date Country Kind
2006-113446 Apr 2006 JP national
2007-061725 Mar 2007 JP national