Patent Application
20220318580
The aspect of the embodiments relates to an apparatus that records an image on a recording medium, a method, and a storage medium.
A recording apparatus based on a so-called multipass printing method has been proposed which records an image by performing print scanning multiple times over a unit area on a recording medium using a print head having a discharge opening array in which a plurality of discharge openings for discharging ink are arranged. Recording data corresponding to the print scanning performed multiple times according to the multipass printing method is generated based on image data having 1-bit information indicating discharge or non-discharge of ink for each pixel and a mask pattern having 1-bit information indicating permission or prohibition of the discharge of the ink for each pixel. In recent years, a method of generating recording data, based on image data having multiple-bit information in which the number of ink discharge times can be set in multiple ways for each pixel and in which a plurality of mask patterns having multiple-bit information for setting the number of times to permit the ink discharge for each pixel has also been proposed. According to this method, ink can be applied to a single pixel area multiple times.
Processing for reducing an application amount of ink has been proposed to suppress bleeding of the ink in an edge area or the like of an object. Japanese Patent Laid-Open No. 2005-1190 describes a method of thinning out multivalued data of pixels corresponding to the edge area at a certain ratio, and a method of replacing the multivalued data with data of different dot sizes.
According to an aspect of the embodiments, there is provided an apparatus including an identification unit configured to identify, in L-tonal (L 3) image data in which each of pixels is represented by bit data of M bits (M 2), a target pixel on which reduction processing is to be executed, and a reduction processing unit configured to reduce a grayscale value of the identified target pixel, in which the reduction processing unit reduces the grayscale value, based on the bit data of M bits corresponding to the target pixel and mask pattern data corresponding to the target pixel.
Further features of the disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Hereinafter, an embodiment of the disclosure will be described with reference to the drawings.
A platen 104 is arranged inside the ink jet recording apparatus, and a large number of suction holes (not illustrated) are formed on the platen 104 to suction a recording medium 103 to avoid floating. These suction holes are connected to a duct, and furthermore, a suction fan (not illustrated) is arranged below the duct. When this suction fan operates, the suction of the recording medium 103 is carried out via the platen 104.
A carriage 102 is supported with a main rail 108 installed to extend in a paper width direction and configured to be able to reciprocally move in an X direction (cross direction). Print heads 110 to 113 based on an ink jet method which will be described below are mounted to the carriage 102. The print heads 110 to 113 of the present embodiment are based on a thermal jet method using a heating element as a recording element, but various recording methods such as a piezoelectric method using a piezoelectric transducer can be applied to the print heads. A carriage motor 205 which is not illustrated in
The recording medium 103 is wound off and fed from a rolled medium and conveyed in a Y direction (conveyance direction) intersecting with the X direction on the platen 104. A leading edge of the recording medium 103 is pinched by pinching rollers (not illustrated) and conveyance rollers (not illustrated), and the conveyance rollers are driven by a conveyance motor 204, so that a conveyance operation is carried out. A mode in which the discharged recording medium 103 is directly discharged to the outside of the apparatus, or a mode in which the discharged recording medium 103 is wound like a roll by a winding apparatus 106 may also be adopted. In addition, the recording medium may be a cut sheet.
The discharge openings 301 are connected to respective ink tanks, which are not illustrated in the drawing, housing the corresponding types of ink by tubes 105, and the ink is supplied via the tubes 105. It is noted that the print heads 110 to 113 used in the present embodiment and the ink tanks may be integrally configured or may be configured to be separatable from each other.
Each drive circuit, such as the conveyance motor 204 and the carriage motor 205, is connected to the recording control unit 201 via a corresponding motor driver 202 or 203. Each of the motors is driven based on moving distances of the carriage 102 and the recording medium 103 which are instructed from the recording control unit 201, and ink droplets are discharged from the print heads 110 to 113, based on position information of the carriage 102 and the recording medium 103 to record an image on the recording medium 103.
According to the present embodiment, image data having M-bits (M≥2: M is an integer higher than or equal to 2), L-tonal (L≥3) tone information per pixel is generated as the recording data of each of the ink colors. It is noted that in the following description, a case where information of 2 bits per pixel is included as image data indicating a pixel value of each pixel will be described. The M-bit tone information according to the present embodiment may be information for setting the number of ink discharge times to discharge ink droplets with an identical amount to the pixel up to (2{circumflex over ( )}M−1) times or may be ink discharge amount information of (2{circumflex over ( )}M−1) types where the amount per droplet of the ink droplets varies. According to the present embodiment, the M-bit tone information is information of the number of the ink discharge times which indicates the number of ink droplets to be applied to the pixel. It is noted that when a print head that can discharge ink droplets in a plurality of sizes is used, binarization processing which will be described below can be omitted, and the M-bit, L-tonal image data can be used as the recording data.
Next, in step S1002, color conversion processing for converting the image data 403 into data corresponding to ink colors used in recording is performed by the CPU 401 and the image processing unit 406. Next, in step S1003, quantization processing based on dithering or error diffusion is performed on the data corresponding to each ink described above by the CPU 401 and the image processing unit 406. With this configuration, multivalued image data of 2 bits indicating a grayscale value of the ink for each of the pixels is generated. In this multivalued image data, any of the pixel values “00”, “01”, “10”, and “11” is set for each of the pixels. It is noted that according to the present embodiment, a flow for executing the quantization processing on data after the color conversion processing will be described, but conversion processing may be performed to generate multivalued data of M bits for each pixel as output data of the color conversion processing.
In step S1004, correction processing for correcting pixel values in an edge area of an image is performed by the CPU 401 and the data processing unit 405. According to the present embodiment, edge processing for correcting image data of chromatic color ink including cyan, magenta, and yellow corresponding to an edge area of the black ink is executed. A detail of this edge processing will be described below.
In step S1005, the binarization processing for generating binary data indicating discharge or non-discharge of the ink for each pixel is performed on the multivalued data after the edge processing which is obtained in step S1004 by the CPU 401 and the data processing unit 405. This binarization processing includes processing for performing resolution conversion on the multivalued data, based on a submatrix pattern, and thinning processing based on a mask pattern. It is however noted that according to the present embodiment, since a resolution of the image data after the quantization processing is the same as a print resolution of the print head, the resolution conversion based on the submatrix pattern is not performed, and the thinning processing on the data after the edge processing is implemented.
Here, the binarization processing of the present embodiment will be described. Both the image data after the quantization processing and mask pattern data 404 are set as 2-bit data herein.
In the mask pattern data used in the present embodiment, one of “01”, “10”, and “11” is set at each pixel position of the mask pattern. Thus, in multipass printing, for the image data “01”, since the ink is discharged only when the mask pattern data is “11”, one dot is recorded. In addition, for the image data “10”, since the ink is discharged when the mask pattern data is “10” and “11”, two dots are recorded. Furthermore, for the image data “11”, since the ink is discharged when the mask pattern data is “01”, “10”, and “11”, three dots are recorded. In this manner, one to three dots can be recorded in accordance with the grayscale value of the image data and the mask pattern data.
Next, the edge processing will be described. According to the present embodiment, in each image data of the chromatic color ink including yellow, magenta, and cyan, the correction processing is executed on pixels adjacent to pixels to which the black ink is to be applied. This is for suppressing sharpness reduction due to bleeding of the black ink into an area of the chromatic color ink in the vicinity of an area to which the black ink is applied. When the number of dots of the chromatic color ink to be recorded is decreased in the pixels adjacent to the pixels to which the black ink is to be applied, it is possible to suppress the bleeding of the black ink into the chromatic color area.
It is noted that an area set as a target of the above-described reduction processing for reducing the application amount of the ink is not limited to a chromatic color ink area adjacent to an edge section of the black area. It is sufficient when the target of the reduction processing is selected according to a combination with which the bleeding is conspicuous due to color value difference or surface tension difference of the ink, and a different combination can be appropriately selected according to a situation such as the cyan ink or the magenta ink.
Here, the edge processing of the present embodiment will be described. Hereinafter, a range with a thickness of one pixel which surrounds the area to which the black ink is applied is referred to as an “edge area”, and the reduction processing is performed for reducing the multivalued data of the chromatic color ink to be applied to this edge area.
Next, in step S1103, the image data of the cyan ink is divided into image data corresponding to the edge area and image data corresponding to an area other than the edge area.
In step S1104, the reduction processing on the edge area is performed. According to the present embodiment, thinning processing based on a mask pattern is performed on the above-described bit data of
It is noted that when a size of units of the quantization processing in step S1003 of
In step S1105, single data is generated by combining the data of the edge area which has been reduced using the mask pattern with the data of the area that is not the target of the reduction processing of
In step S1106, it is determined whether the edge processing is also ended on the image data other than the cyan ink. When the edge processing is not ended, the processing is also performed on the image data of the ink color set as the target of the edge processing, and when the edge processing is ended on the image data other than the cyan ink, since the edge processing is ended, the processing returns to the flow of
With reference to
Herein, recording data is generated in which the multivalued data after the edge processing is to be used for the single scanning operation using the decode mask.
As described above, when the reduction processing is performed using the mask pattern on a bit by bit basis on the bit data quantized into M bits per pixel in the edge processing, it is possible to reduce the pixel value of the multivalued data of the edge area. As a result, the bleeding between the different ink types can be reduced while processing load associated with the reduction processing is suppressed.
According to the above-described embodiment, the bit data is reduced by performing the thinning of the edge area using the single mask pattern. A thinning ratio of the mask pattern may be changed according to a grayscale value of quantization data of each of the pixels. In view of the above, according to the present embodiment, a method of adjusting a chromatic color ink thinning amount in the edge area by setting a mask pattern according to the grayscale value of each of the pixels in the image data of the chromatic color ink will be described.
Next, in step S1202, chromatic color ink data on which the edge processing is to be performed is selected. Herein, the cyan ink is selected. In step S1203, the image data of the cyan ink is divided into edge area data and non-edge area data other than the edge area. A division method is similar to that of the above-described embodiment. In step S1204, the area is further divided according to the grayscale value of each of the pixels included in the edge area to generate image data according to the grayscale value, and in step S1205, mask patterns at corresponding thinning rates are set for respective pieces of the image data of the different grayscale values.
Herein, it is sufficient when the mask pattern having the grayscale value of “2” masks one upper-order bit of each of the pixels, and it is sufficient when the mask pattern having the grayscale value of “1” masks one lower-order bit of each of the pixels.
In step S1206, the thinning processing is performed using the mask pattern of
As described above, the mask pattern is set such that with regard to the pixels of the cyan ink which are adjacent to the pixels to which the black ink is to be applied, the pixel where the number of application dots is higher has a higher ratio of the reduction processing. According to the present embodiment, the pixels where the input grayscale value is “3” are subjected to such thinning that the number of dots is to be fewer than the half (approximately 40%). The pixels where the input grayscale value is “2” are subjected to such thinning that the number of dots is substantially halved. The pixels where the input grayscale value is “1” are subjected to such thinning that the number of dots are left to be more than the half (approximately 65%). As a result, the thinning rate is higher as the pixel has a higher number of dots at a boundary section between the black ink and the cyan ink, and it is possible to suppress bleeding at the boundary section. Furthermore, since the thinning rate of the dots is lower as the pixel has a lower number of application dots where the bleeding causes little effect, it is possible to suppress generation of a void at the boundary section due to excessive thinning of the dots.
When the reduction processing using the mask patterns for the bit data for the different grayscale values as described above is implemented, as compared with a case where subtraction processing is performed according to the grayscale value for each pixel, the ink application amount can be appropriately reduced while the processing load is alleviated.
In image data converted to have M bits, a specific bit of the data with the M bits may have information of an attribute (such as a character or a line) of an image. In the edge processing described according to the above embodiment, since information desired to be referred to is the grayscale value of each of the pixels, the reduction processing is to be performed on specific bit data at the time of the edge processing. In view of the above, according to the present embodiment, a case will be described where a most significant bit is attribute information in the quantization data when M is higher than or equal to 3.
In the following description, M=3 is set, and two lower-order bits are set as grayscale value information.
According to the present embodiment too, the processing is similarly performed as in the flow of
With the above-described processing, the attribute information of the image is held even after the edge processing. The submatrix pattern can be switched at the time of the binarization processing in step S1005 depending on a value of the most significant bit indicating the held attribute information of the image, or the mask pattern can be switched by a combination with the decode table. Specifically, when a value of the bit indicating the attribute information is “1”, in the binarization processing based on the submatrix pattern, a ratio of dots to be recorded by specific scanning can be increased. Alternatively, in the binarization processing using the mask pattern, the mask pattern can be switched such that a ratio of the recording by the specific scanning is increased in a distribution ratio to multiple scanning operations in the combination with the decode table of
In this manner, the attribute information included in the multivalued data of each of the pixels can be held at the time of the edge processing while the load associated with the edge processing on the multivalued image data is suppressed, and the attribute information can also be used in the binarization processing after the edge processing.
According to the above-described embodiment, the configuration is adopted where the section with the thickness of the one pixel on the chromatic color ink side in the boundary area where the black ink is adjacent to chromatic color ink is set as the edge area to thin out the bit data to reduce the application amount of the chromatic color ink, but the target of the reduction processing is not limited to the above-described method. A configuration may also be adopted where the application amount on the black ink side is thinned out, and in this case, an end portion of the area to which the black ink is to be applied may be set as the edge area.
In addition, the pixels set as the target of the reduction processing are not limited to areas with different ink colors which are adjacent to each other.
For example, in a character image or a line drawing image, to suppress bleeding of ink at a contour portion into a blank area on paper to which the ink is not applied, a boundary area of an object such as characters or line drawings may be set as the target of the reduction processing. Either one or both of pixels to which the ink on an inner side of the boundary area is applied and pixels to which the ink on an outer side of the boundary area is not applied may be appropriately set as the edge area. In addition, to improve fixability of the ink, an inner area (non-edge area) of the characters or the line drawings may be set as the target of the reduction processing. Moreover, when a full surface of the image data is to be thinned out, the processing for identifying the target pixels of the reduction processing may be omitted, and the mask pattern may be applied to all the pieces of bit data to perform the thinning processing. The target pixels of the reduction processing are not limited to these examples, and may be appropriately selected.
According to the embodiments of the disclosure, when the mask pattern is used for the bit data of M bits (M≥2) per pixel, the reduction processing can be performed while the increase in the processing load is suppressed.
Embodiment(s) of the disclosure can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like.
While the disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure 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 such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2021-060647 filed Mar. 31, 2021, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-060647 | Mar 2021 | JP | national |
