Ejection position data generation method, ejection position data generation device, and program

Abstract

Suitably improve the quality of printing. A jet position data generation method for generating jet position data indicating jet positions at which ink is jetted, the jet position data generation method including edge detection processing (S202), edge correction processing (S204), and jet position data generation processing (S110) based on processing target data indicating an image to be printed, the processing target data being data in which pixel values of pixels are set to non-jet values or jet values, the non-jet values being values indicating that ink is not to be jetted at corresponding jet positions, the jet values being values other than the non-jet values, in the edge detection processing, edges are detected by detecting positions at which pixels set to the non-jet values and pixels set to the jet values are adjacent, in the edge correction processing, for at least a portion of the jet positions at which ink is to be jetted in order to depict the edges, pixel values of corresponding pixels are changed to the non-jet values.

Description

Technical Field

[0001] This invention relates to a method, apparatus and program for generating ejection position data. Background Technology

[0002] In the past, inkjet printers, which perform printing using inkjet technology, have been widely used. When printing with an inkjet printer, the printing apparatus ejects ink based on data generated by a RIP (Raster Image Processor) (see, for example, Patent Document 1). In this case, the inkjet printer ejects ink from the printhead to an ejection position set according to the printing resolution based on this data, thereby performing printing on the medium to be printed. Furthermore, in the RIP processing, data indicating the ejection position of the ink ejected from the inkjet printer is generated.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-110989 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] Ink ejected from the inkjet head onto the medium typically diffuses on the surface of the medium after landing on it. Furthermore, in this case, it is conceivable that, considering factors such as filling the medium as needed, the size of the ink diffusion on the medium can be set in a way that generates dot gain, where the ink droplets diffuse to a range wider than the range corresponding to a single ejection position determined by the printing resolution.

[0008] However, in this situation, dot gain sometimes occurs even outside the filled area, making it difficult to print with the desired quality. More specifically, for example, it is conceivable that due to dot gain occurring in areas depicting thin lines, the output lines are thicker than intended. Additionally, it is conceivable that due to dot gain occurring in areas depicting cutout characters, the cutout portions are filled in, etc. Moreover, it is conceivable that these phenomena make it difficult to print with the desired quality, resulting in a decrease in print quality. Therefore, higher quality printing has always been desired. Therefore, the object of the present invention is to provide a method, apparatus, and program for generating ejection position data that can solve the above-mentioned problems.

[0009] Solution for solving the problem

[0010] To address the aforementioned problems, the inventors of this application conceived of performing image processing on the image printed by a printing apparatus for edge correction. More specifically, they conceived of a method in which at least a portion of the ink ejection position from the inkjet head for edge depiction is changed, for example, to a position where no ink is ejected. With this configuration, the appearance of the edges in the printed result can be appropriately altered. Furthermore, this can, for example, appropriately prevent the output of lines thicker than intended in areas where fine lines are to be depicted, and prevent the filling of hollowed-out portions in areas where hollowed-out characters are to be depicted.

[0011] Furthermore, through further in-depth research, the inventors of this application discovered the features required to achieve such an effect, thus completing the present invention. To solve the aforementioned problems, the present invention provides an ejection position data generation method for generating ejection position data, which represents the ejection position of ink ejected from an inkjet head in a printing apparatus. The ejection position data generation method is characterized by performing the following processes: edge detection processing, detecting edges for at least a portion of the image based on image data representing an image printed in the printing apparatus, i.e., processing object data; edge correction processing, performing image processing on the image to correct the edges detected in the edge detection processing; and ejection position data generation processing, generating the ejection position data in a manner reflecting the result of the image processing in the edge correction processing, wherein the processing object data represents... The image data, composed of pixels corresponding to the ejection position, includes processing object data with either a non-ejection value or an ejection value set as the pixel value for each pixel. The non-ejection value indicates that ink is not ejected at the corresponding ejection position, and the ejection value is a value other than the non-ejection value. In the edge detection process, the edge is detected by detecting the adjacent positions of pixels with the non-ejection value and pixels with the ejection value. In the edge correction process, for at least a portion of the ejection positions from which ink is ejected from the inkjet head in order to depict the edge detected in the edge detection process, the pixel value of the corresponding pixel is changed to the non-ejection value, thereby performing the image processing for correcting the edge.

[0012] With this configuration, edge correction can be performed appropriately. Furthermore, this can appropriately improve the printing quality performed in the printing apparatus. More specifically, with this configuration, edge correction can, for example, prevent the output of lines thicker than intended in areas where fine lines are drawn, and prevent the filling of cutouts in areas where cutout characters are drawn.

[0013] In this structure, the edge correction action can also be considered as an action of adjusting the pixels representing the image to be printed. Furthermore, in this structure, during edge correction processing, it is possible to set the pixel values ​​of pixels within a predetermined width range from the edge to non-ejection values. More specifically, in this case, during edge correction processing, the following image processing can be considered: changing the pixel values ​​of pixels within a predetermined number of pixels from the boundary of the edge being corrected, and which are set with ejection values, to non-ejection values. If configured in this way, for example, the effect of dot gain can be appropriately suppressed, and edges can be sharpened.

[0014] Furthermore, it is preferable that the edge correction process is performed in a manner that prevents lines from disappearing due to correction. More specifically, in the edge correction process, image processing can be performed on the image in a way that prevents lines from disappearing due to edge correction, taking into account edges that correspond to lines below a predetermined line width detected in the edge detection process. If configured in this way, edge correction can be performed more appropriately.

[0015] Furthermore, in this structure, a color printer that uses multiple colors of ink for color printing can be considered as the printing apparatus. In this case, image acquisition processing and plate separation processing can be performed during the generation of ejection position data. Regarding image acquisition processing, this can be considered as the process of acquiring color image data, which represents the color image being printed in the printing apparatus. Regarding plate separation processing, this can be considered as the process of generating grayscale images corresponding to each color of the multiple colors of ink used in the printing apparatus. In the plate separation processing, grayscale images corresponding to each color are generated by separating the color image according to each color of the multiple colors of ink. In this case, data representing the grayscale images corresponding to each color can be used as the processing object data. With this configuration, edge correction can be appropriately performed for each color of ink used in the printing apparatus. Furthermore, the quality of the printed image can be improved more appropriately.

[0016] Furthermore, in this structure, edge detection and correction can be performed on the entire image represented by the processing object data. Alternatively, edge detection and correction can be performed on only a portion of the image represented by the processing object data. When edge detection and correction is performed on only a portion of the image represented by the processing object data, processing object data that allows selection of a portion of the image can be used. More specifically, in this case, data that allows selection of a target portion of the image as distinct from other portions can be used as processing object data. In this case, edge detection is performed on edges within the pre-selected target portion. In edge correction, the edges detected within this target portion are corrected. This configuration allows for more appropriate edge correction that aligns with the user's intentions. Furthermore, in this case, for example, edge detection and correction can be performed on a target portion that corresponds to a part important for representing fine lines, such as parts representing characters.

[0017] Furthermore, in this case, it is possible to consider using an auxiliary image for target region selection. This auxiliary image is composed of pixels with auxiliary values ​​set for selecting the target region. More specifically, in edge detection processing, it is possible to use auxiliary data representing an image with auxiliary values ​​set for each pixel—that is, an auxiliary image—where the auxiliary values ​​have a different purpose than those set for color representation. The portion of pixels in the image represented by the processing object data that corresponds to pixels in the auxiliary image with predetermined auxiliary values ​​set in the auxiliary image is considered the target region for detection, and edges within this target region are detected. With this configuration, target region selection can be performed easily and appropriately.

[0018] Auxiliary data can be considered as image data that represents images with auxiliary values ​​set for pixels. Furthermore, as such auxiliary data, channels (such as alpha channels) prepared separately from the color channels in data representing a color image with multiple color channels corresponding to multiple colors can be considered.

[0019] Alternatively, it is also possible to select the target portion based on user instructions received using an input device such as a mouse. In this case, range selection processing can also be considered, in which the user receives instructions to select a range of a portion of the image. Furthermore, in edge detection processing, the portion of pixels in the image represented by the processing object data that falls within the range selected by the user in the range selection processing is considered a target portion distinguished from other portions of the image, and edges within this target portion are detected. With this configuration, the selection of the target portion can be performed easily and appropriately.

[0020] Furthermore, the features of the present invention can also be considered by focusing on using the grayscale image generated in the page separation process for edge detection and edge correction processing. In this case, the edge correction processing can also be considered as an image processing operation that corrects the edges by reducing the amount of ink ejected from at least a portion of the ejection position of the inkjet head to depict the edges detected in the edge detection processing. Additionally, as a structure of the present invention, it is also possible to consider using an ejection position data generation device, program, etc., having the same features as described above. In these cases, the same effects as described above can also be obtained.

[0021] The effects of the invention

[0022] According to the present invention, the quality of printing performed in a printing apparatus can be appropriately improved. Attached Figure Description

[0023] Figure 1 This is a diagram illustrating an example of the structure of a printing system 10 according to an embodiment of the present invention. Figure 1 (a) shows an example of the structure of the printing system 10. Figure 1 (b) shows an example of the structure of the printing execution unit 12 in the printing system 10.

[0024] Figure 2 This is a flowchart illustrating an example of the action of generating RIP generation data in the RIP processing unit 14.

[0025] Figure 3 This is a diagram illustrating the rationale for edge correction. Figure 3 (a) and (b) show examples of data and output results representing thin lines. Figure 3 (c) and (d) show examples of data and output results representing fine cutout characters.

[0026] Figure 4 This is a diagram illustrating an example of edge correction performed in this case. Figure 4 (a) and (b) show examples of data and output results representing thin lines. Figure 4 (c) and (d) show examples of data and output results representing fine cutout characters.

[0027] Figure 5 This is a diagram illustrating the edge correction action performed in this example. Figure 5 (a) is a diagram illustrating the actions in edge detection processing. Figure 5 (b) shows an example of the output results when printing was performed without edge correction. Figure 5 (c) shows an example of the edge correction process. Figure 5 (d) shows an example of the printed output after edge correction.

[0028] Figure 6 This is a diagram illustrating an example of edge correction. Figure 6 (a) to (d) show examples of edge correction for lines of various widths.

[0029] Figure 7 This is a diagram illustrating a variation of edge correction processing. Figure 7 (a) and (b) show examples of changing the range of pixel values ​​in a variation of edge correction processing.

[0030] Figure 8 This is a diagram illustrating the effect of edge correction processing. Detailed Implementation

[0031] The embodiments of the present invention will now be described with reference to the accompanying drawings. Figure 1 An example of the structure of a printing system 10 according to one embodiment of the present invention is shown. Figure 1 (a) shows an example of the structure of the printing system 10. Figure 1 (b) shows an example of the structure of the printing execution unit 12 in the printing system 10. Except for the aspects described below, the printing system 10 of this example may have the same or identical features as known printing systems.

[0032] In this example, the printing system 10 is a system that prints on a medium 50, which is the object of printing, using inkjet printing. It includes a printing execution unit 12 and a RIP processing unit 14. The printing execution unit 12 is an example of a printing apparatus and is the part that performs the printing operation of ejecting ink from the medium 50. The printing execution unit 12 can also be considered as the main body of an inkjet printer, etc. In this example, the printing execution unit 12 receives RIP generation data, such as ejection position data, from the RIP processing unit 14, and performs ink ejection according to the RIP generation data, thereby performing the printing operation on the medium 50. In this case, the ejection position data can be considered as data indicating the ejection position of ink ejected from the inkjet head in the printing apparatus. Furthermore, the RIP generation data can be considered as data generated by RIP (Raster Image Processor) processing, etc.

[0033] In this example, the printing execution unit 12 is a color printer that uses multiple colors of ink, each a different color, for color printing. It includes a printing platen 104, a main scanning drive unit 106, a secondary scanning drive unit 108, a control unit 110, and multiple inkjet heads 102. Each inkjet head 102 is a printhead that ejects ink in an inkjet manner, ejecting the ink of each color used in printing. In this case, it is possible for each of the multiple inkjet heads 102 to eject ink of a different color. More specifically, in this example, each of the multiple inkjet heads 102 ejects ink of each process color, which is a basic color in color printing. Examples of process colors that can be used are yellow (Y), magenta (M), cyan (C), and black (K). Furthermore, each inkjet head 102 has multiple nozzles arranged in a predetermined nozzle row direction, and ink is ejected from each nozzle in the nozzle row. In this example, the nozzle array direction is parallel to the sub-scanning direction (X direction in the figure) preset in the printing execution unit 12. In this case, in each inkjet head 102, multiple nozzles are arranged in a manner that staggers their positions in the sub-scanning direction by arranging them along the nozzle array direction.

[0034] Furthermore, in this example, each of the multiple inkjet heads 102 is an inkjet head that ejects only one type of droplet (ink droplet). In this case, regarding ejecting only one type of droplet, it can be considered that the design capacity of the ink droplets ejected from each nozzle of the inkjet head is one type. Additionally, regarding ejecting only one type of droplet, it can also be considered that the ink ejection from each nozzle is controlled by whether or not ink is ejected. Furthermore, in this example, the capacity of the droplets ejected from each nozzle of the inkjet head is the capacity of the ink droplet spreading to a range wider than a single point determined by the printing resolution. In a modified structure of the printing execution unit 12, for example, it is also possible to consider using inkjet heads that eject multiple types of droplets as each inkjet head 102. In this case, regarding inkjet heads that eject multiple types of droplets, it can also be considered as multi-value heads that can set droplet capacity at multiple levels.

[0035] The platform 104 is a platform-shaped member on which the medium 50 is placed, holding the medium 50 in a state facing the plurality of inkjet heads 102. The main scan drive unit 106 is a drive unit that causes the plurality of inkjet heads 102 to perform main scan operations. In this case, the main scan operation can be considered as an operation of ejecting ink while moving relative to the medium 50 in a predetermined main scan direction. In this example, the main scan direction is a direction orthogonal to the sub-scan direction (the Y direction in the figure). During the main scan operation, the main scan drive unit 106, under the control of the control unit 110, causes each nozzle of each of the plurality of inkjet heads 102 to eject ink to an ejection position set according to the printing resolution. In this case, the ejection of ink from the inkjet head 102 to the ejection position can be considered as ejecting ink to the ejection position specified by the RIP generation data among the ejection positions set according to the printing resolution. The sub-scan drive unit 108 is a drive unit that causes the plurality of inkjet heads 102 to perform sub-scan operations. Regarding the sub-scanning action, it can be considered as an action of moving in the sub-scanning direction relative to the medium 50. Alternatively, the sub-scanning action can also be considered as an action of conveying the medium 50 in the sub-scanning direction relative to the multiple inkjet heads 102 during the intervals of the main scanning action.

[0036] The control unit 110, for example, includes a CPU or similar component in the printing execution unit 12, and controls the operation of each part of the printing execution unit 12. In this example, the control unit 110 controls the operation of each part of the printing execution unit 12 based on the RIP generation data received from the RIP processing unit 14. Furthermore, the control unit 110 thereby causes the printing execution unit 12 to perform the printing operation.

[0037] RIP processing unit 14 is an example of an ejection data generation unit. It performs RIP processing based on input data representing an image to be printed in printing execution unit 12, thereby generating RIP generation data. Furthermore, RIP processing unit 14 provides the generated RIP generation data to printing execution unit 12, thereby controlling the operation of printing execution unit 12. In this case, RIP processing unit 14 performs RIP processing, for example, based on the structure of printing execution unit 12 and the settings of the printing operations performed in printing execution unit 12, thereby generating RIP generation data. More specifically, in this example, RIP processing unit 14 generates data indicating at least a plurality of ejection positions that should be ejected from the ink at according to the printing resolution, as RIP generation data.

[0038] The RIP processing unit 14 can be, for example, a computer that executes a RIP processing program (software). Furthermore, the RIP processing unit 14 can also be considered as a computer that controls the operation of the printing execution unit 12. The operation of generating RIP generation data in the RIP processing unit 14 will be explained in more detail below.

[0039] Figure 2 This is a flowchart illustrating an example of the operation of generating RIP generation data in the RIP processing unit 14. In the operation of generating RIP generation data, the RIP processing unit 14 first acquires input data representing an image (printed image) to be printed in the printing execution unit 12 (S102). In this example, the operation performed in step S102 is an example of image acquisition processing. Furthermore, in step S102, the RIP processing unit 14 acquires data representing a color image printed in the printing execution unit 12, i.e., color image data, as input data. The process of acquiring color image data in step S102 can be performed in the same or similar manner as the operations performed in known RIP processes.

[0040] Furthermore, in this example, the RIP processing unit 14 performs resolution transformation on the color image data acquired in step S102 according to the printing resolution performed in the printing execution unit 12 (S104). In this case, by performing resolution transformation according to the printing resolution, it is possible to correspond the pixels of the image represented by the transformed color image data with the ejection position of the ink ejected from the inkjet head by the printing execution unit 12. The resolution transformation process performed in step S104 can also be performed in the same or similar manner as the operations performed in known RIP processes.

[0041] Furthermore, following the actions in step S104, the RIP processing unit 14 performs plate separation processing (S106). Plate separation processing can be considered as processing the color image representing the image printed in the printing execution unit 12 to separate plates based on the colors of the inks used in printing. Alternatively, plate separation processing can also be considered as processing the generation of grayscale images corresponding to each of the multiple colors of ink used in the printing execution unit 12. In this example, the RIP processing unit 14 separates the color image after resolution transformation in step S104 based on each of the multiple colors of ink used during printing in the printing execution unit 12, thereby generating grayscale images corresponding to each color. More specifically, in this example, the RIP processing unit 14 generates grayscale images corresponding to each of the YMCK colors. The plate separation processing can also be performed in the same or similar manner as the actions performed in known RIP processing.

[0042] In this example, the data representing the grayscale images generated in step S106 corresponding to each color of ink is an example of processing target data. Processing target data can be considered as the data to be processed in the subsequent step S108. In this example, processing target data can also be considered as image data representing the image printed in the printing execution unit 12. Furthermore, the data representing each grayscale image corresponding to each color of ink can be considered as tone image data representing the image printed with the corresponding color ink in a predetermined tone. Additionally, grayscale images can also be considered as images represented by three or more tones. More specifically, in this example, the RIP processing unit 14 generates grayscale images with approximately 8 bits (e.g., 4 to 16 bits) of tone corresponding to each color of ink.

[0043] Furthermore, following the actions in step S106, the RIP processing unit 14 performs edge detection and correction in the image (S108). In this case, edges can be considered, for example, the boundary between an object and the background in the image, continuous boundary portions in the outline of an object, or the continuity of pixels constituting the outline of an object. In this example, as an action in step S108, the RIP processing unit 14 performs edge detection processing (S202) and edge correction processing (S204). In this case, in step S202, the RIP processing unit 14 performs edge detection processing on at least a portion of the image based on data representing the grayscale image generated in step S106. In step S204, the RIP processing unit 14 performs image processing on the image represented by the grayscale image to correct the edges detected in step S202. The edge detection and correction actions performed in steps S202 and S204 will be explained in more detail later.

[0044] Furthermore, following the actions in step S108, the RIP processing unit 14 generates RIP generation data (S110). In this case, the RIP processing unit 14 generates RIP generation data based on the grayscale image after edge correction in step S204 of step S108, thereby generating RIP generation data in a manner that reflects the image processing results in the edge correction process. Additionally, in this case, the processing for generating RIP generation data, except for using the edge-corrected grayscale image, can be performed in the same or identical manner as the actions performed in known RIP processing.

[0045] More specifically, in this example, as an action in step S110, the RIP processing unit 14 performs quantization processing (S212) and command processing (S214). In this case, in step S212, the RIP processing unit 14 performs quantization processing on each grayscale image corresponding to each color of ink to reduce the number of tones. Quantization processing can be considered as reducing the number of tones to a number that can be represented by the volume of droplets (ink droplets) that can be ejected from the inkjet head. Quantization processing can also be considered as halftone processing based on the structure of the inkjet head. Furthermore, as explained above, the inkjet head in the printing execution unit 12 in this example ejects only one volume of droplets. In this case, quantization processing can be considered as image binarization processing. More specifically, the RIP processing unit 14 transforms the grayscale image into a binary bitmap by performing quantization processing. In this case, in the binary bitmap generated through quantization processing, one of the binary values ​​can be considered to represent the position where ink is ejected from the inkjet head, within the ejection position set according to the printing resolution. The other value can be considered to represent the position where no ink is ejected. Furthermore, this binary bitmap can be considered an image representing the position where ink is ejected from the inkjet head, etc.

[0046] Furthermore, as explained above, in variations of the structure of the printing execution unit 12, it is possible to consider using an inkjet head that ejects droplets of various capacities. In this case, the quantization process can be considered as reducing the number of tones in the image to a number of tones corresponding to the type of droplet capacity. Additionally, in this case, it is possible to consider performing image binarization processing for each droplet capacity.

[0047] Furthermore, in step S214, the RIP processing unit 14 commands the data representing the binary bitmap generated by the quantization process in step S212. In this case, commanding can be considered as processing the data to transform it into a form that can be processed by the printing execution unit 12. Additionally, the RIP processing unit 14 generates RIP generation data based on the data representing the binary bitmap generated by the quantization process using this commanding command.

[0048] According to this example, RIP generation data can be appropriately generated based on input data representing an image being printed in the printing execution unit 12. Furthermore, in this case, the RIP generation data can be considered as data representing the position of ink ejection from the inkjet head, among other things, within the ejection position set according to the printing resolution. Additionally, as described above, according to this example, edge correction processing can be appropriately performed during the RIP generation data generation process. Furthermore, in this example, the RIP processing unit 14 controls the operation of the printing execution unit 12 by providing the RIP generation data to the printing execution unit 12. Therefore, according to this example, the printing execution unit 12 can appropriately perform printing operations reflecting the results after edge correction.

[0049] Furthermore, as explained above, in the action of generating RIP generation data in this example, actions other than those in step S108 can be performed in the same way or identically as those performed in known RIP processing. Additionally, for ease of explanation, some specific actions performed to generate RIP generation data have been appropriately omitted above. Therefore, in the RIP processing unit 14, in addition to the actions described above, actions that are the same as or identical to those performed in known RIP processing can also be performed. For example, if printing is performed in a multi-pass printing manner in the printing execution unit 12, it is possible to consider performing data segmentation based on the actions in the multi-pass printing manner in the RIP processing unit 14.

[0050] Next, the edge detection and correction actions performed in steps S202 and S204 will be explained in more detail. First, using... Figure 3 and Figure 4 This section provides an overview of the reasons for edge correction, examples of edge correction, and other relevant information. Figure 3 This diagram illustrates the rationale for edge correction and shows examples of problems that arise when edge correction is not performed.

[0051] Figure 3(a) and (b) are diagrams showing examples of data and output results representing thin lines. For a thin line with a width of 2 pixels in the vertical direction and a length of 10 pixels in the horizontal direction, the diagrams show examples of data-based images and output results in the printing execution unit 12. Figure 3 Figures (c) and (d) illustrate examples of data and output results representing fine cutout characters. Regarding the case where the character "-" is depicted as having a vertical width of 1 pixel and a horizontal length of 11 pixels, examples of data-based images and the output results in the printing execution unit 12 are shown. Furthermore, in these figures, the data-based images can be considered, for example, images represented in the RIP generation data. Additionally, the output results in the printing execution unit 12 can be considered as lines drawn on the medium by ink droplets ejected from the inkjet head.

[0052] Furthermore, as explained above, in this example, the capacity of the ink droplets ejected from each nozzle of the inkjet head is the capacity of the ink droplet to spread over a range wider than the range of a single dot determined by the printing resolution. More specifically, for example, in the case of a printing resolution of 600 dpi, the width of one pixel is approximately 42 μm. In contrast, in this example, the width of the range of a single dot's spread is larger than 42 μm. In this case, the width of the range of a single dot's spread can be considered to be the width corresponding to the diameter when the shape of the ink droplet is approximated by a circle. Furthermore, more specifically, in this example, the width of the range of a single dot's spread is approximately 50 to 90 μm.

[0053] Furthermore, in this case, the ink dots formed at the positions of each pixel in the output of the printing execution unit 12 are formed in a state where a portion of them seeps into the positions of adjacent pixels. Additionally, as a result, sometimes the deviation between the output state and the desired state corresponding to the data-based image becomes larger. More specifically, when it is desired to depict, for example... Figure 3 In the case of the thin lines shown in (a) and (b), one can imagine that the lines are drawn thicker than intended (the original state) due to the seepage of dots, and the color becomes darker due to the effect of overlapping dots. Furthermore, when wanting to draw, for example... Figure 3 In the case of the cutout characters shown in (c) and (d), one can imagine that dots bleed out from the nearby pixels to the parts that do not form ink dots in order to represent the cutout characters. Furthermore, as a result, one can imagine that even the parts that should be cutout characters are filled in, making the characters unreadable.

[0054] In contrast, in this example, edge correction enables higher quality printing. Figure 4 This is a diagram illustrating an example of edge correction performed in this case. Figure 4Figures (a) and (b) are examples of data and output results representing thin lines, regarding the depiction and... Figure 3 Images (a) and (b) show the same case of thin lines, illustrating examples of data-based images and output results from the printing execution unit 12. Figure 4 In (c) and (d), regarding the description and Figure 3 Examples (c) and (d) show the same case of cutout characters, illustrating data-based images and the output results in the printing execution unit 12. Additionally, in Figure 4 In (a) and (c), to represent the desired image to be depicted, images corresponding to the state before correction are shown. Furthermore, the result is that... Figure 4 The images shown in (a) and (c) are related to Figure 3 The images shown in (a) and (c) are the same. In contrast, in Figure 4 In (b) and (d), solid circles represent actual ink dots, and dashed circles represent ink dots that no longer form after correction, thus showing the result of the correction. More specifically, in Figure 4 In (b) and (d), the dashed circle indicates that... Figure 3 In the states of (b) and (d), they are actually formed and in Figure 4 Ink dots that do not form in states (b) and (d)

[0055] In addition, according to Figure 3 (b), (d) and Figure 4 By comparing (b) and (d), one can understand that... Figure 4 In states (b) and (d), for areas depicted by the arrangement of ink dots, remove (omit) the area... Figure 3 In states (b) and (d), the ink dots form the outer periphery, thereby suppressing the effect of ink dots seeping into adjacent pixels. More specifically, in Figure 4 In the cases shown in (b) and (d), with Figure 3 Compared to the cases shown in (b) and (d), the output is done by placing a single pixel at a position where no edge is formed. With this configuration, when drawing thin lines, it is possible to appropriately prevent lines from being drawn thicker than intended, or from becoming too dark in color. Furthermore, when drawing cutout characters, it is possible to appropriately prevent even the parts that should be cutout characters from being filled in, thus preventing the characters from becoming unreadable.

[0056] Furthermore, as can be understood from the above explanation, in this example, edge correction is performed when generating RIP generation data, thereby ensuring that at least a portion of the ejection locations, which are not at the edges, form ink dots. Therefore, the edge correction operation performed in this example will be explained in more detail below. Figure 5 This is a diagram illustrating the edge correction process performed in this example. Figure 5 (a) is a diagram illustrating the actions performed in the edge detection process prior to edge correction.

[0057] As explained above, in this example, the RIP processing unit 14 performs edge detection processing on at least a portion of the image based on data representing the grayscale image generated in the page splitting process. In this case, it is possible to perform edge detection and correction on the entire grayscale image represented by the data. Alternatively, it is possible to perform edge detection and correction on only a portion of the grayscale image. In this case, it is possible to use data in the form of selecting a portion of the image as a target portion to distinguish it from other portions, and then detect edges within the pre-selected target portion. Furthermore, this operation can be considered as an operation that targets only a portion of the target portion as the object of edge detection.

[0058] Furthermore, in this example, the data representing the grayscale image can be considered as data representing an image composed of pixels corresponding to the ink ejection positions in the printing execution unit 12. In this case, any one of the hue values ​​of the grayscale image becomes a non-ejection value, indicating that ink is not ejected to the corresponding ejection position. Other values ​​become ejection values, i.e., values ​​other than non-ejection values. More specifically, in this case, either the maximum or minimum hue value of the grayscale image can be considered as a non-ejection value. Additionally, all (multiple) hue values ​​other than non-ejection values ​​can be considered as ejection values. Moreover, in this example, the RIP processing unit 14 detects the positions adjacent to pixels with non-ejection values ​​and pixels with ejection values, thereby detecting edges. In this case, the RIP processing unit 14 sequentially selects pixels for each grayscale image corresponding to each color of ink used in the printing execution unit 12 and confirms the pixel value of that pixel and the surrounding pixel values, thereby detecting edges.

[0059] As explained above, in this example, the RIP processing unit 14 performs quantization processing on the grayscale image corresponding to each color of ink, thereby generating a binary bitmap representing the position where ink is ejected from the inkjet head. Furthermore, in this case, the pixel values ​​of the binary bitmap corresponding to pixels in the grayscale image that have ejection values ​​set may sometimes become values ​​representing positions where ink is not ejected. Therefore, the ejection and non-ejection values ​​in the grayscale image can be considered not to be values ​​that completely correspond to whether ink is ejected during actual printing, but rather values ​​representing the state of the grayscale image at a given time point.

[0060] In addition, Figure 5 In (a), an arrangement of multiple pixels 202 constituting a part of a grayscale image is schematically shown. In the figure, each grid represents a pixel 202 corresponding to an ejection position set according to the printing resolution. Furthermore, the pixels 202 represented by the grids with shading patterns are pixels with ejection values ​​set. The pixels represented by the grids without shading patterns are pixels with non-ejection values ​​set. Moreover, the thick lines in the figure indicate edges detected in the illustrated case. According to this example, edge detection can be performed appropriately.

[0061] In addition, regarding Figure 5 (a) can be considered to show an image without edge correction. Furthermore, in this case, when RIP generation data is generated without edge correction to perform printing in the printing execution unit 12, sometimes... Figure 5 As shown in (b), ink dots seep out to the position of adjacent pixel 202, thereby reducing the quality of the print. Figure 5 (b) shows an example of the output results when printing was performed without edge correction.

[0062] In contrast, in this example, for instance... Figure 5 As shown in (c), edge correction is performed. Figure 5 (c) illustrates an example of edge correction processing. In this example, the RIP processing unit 14 changes the pixel value of the corresponding pixel 202 to a non-ejection value for at least a portion of the ejection position from the inkjet head to depict the edge detected in the edge detection processing, thereby performing image processing for edge correction. In this case, the pixel value can be considered as the pixel value of pixel 202 corresponding to the ejection position in the grayscale image. More specifically, in... Figure 5 In the case shown in (c), the RIP processing unit 14 changes the pixel value of the pixel adjacent to the edge detected in the edge detection process to a non-ejection value, thereby performing edge correction.

[0063] Furthermore, in this case, the RIP processing unit 14 generates RIP generation data based on the corrected grayscale image. Moreover, in this case, the output of the printing executed in the printing execution unit 12 is as follows: Figure 5 As shown in (d). Figure 5 Figure (d) shows an example of the printed output after edge correction. As can be understood from the figure, this example demonstrates how ink dots can be appropriately prevented from... Figure 5 The edge position shown in (a) diffuses outwards. Furthermore, this allows for appropriate suppression of the effect of point gain, enabling edge sharpening.

[0064] Furthermore, more specifically, in this case, for example, when drawing thin lines, it is possible to appropriately prevent the lines from being drawn thicker than intended, or the colors from becoming too dark. Also, for example, when drawing cutout characters, it is possible to appropriately prevent even the parts that should be cutout characters from being filled in, thus preventing the characters from becoming unreadable. Therefore, according to this example, for example, it is possible to appropriately achieve thinner lines, and high-quality printing can be appropriately achieved. Furthermore, in this example, by using data representing grayscale images generated corresponding to each color of ink in the plate separation process as processing object data in edge detection and edge correction processing, edge correction can be appropriately performed for each color of ink used in the printing execution unit 12. Furthermore, this can further improve the quality of the printed image.

[0065] In addition, Figure 5 In the diagram, for ease of illustration, the size of the ink dots in the output is shown in the diagram to make it easier to observe their relationship with the position of pixel 202 compared to reflecting the actual size. Therefore, regarding... Figure 5 (d) It is possible that the corrected state may not look better than the original state. However, in the actual output, by performing edge correction as described above, it is possible to print a state that is closer to the state represented by the original data.

[0066] Furthermore, the edge correction operation performed in this example can be considered as omitting an ink dot from the pixel surrounding the edge. The edge correction operation can also be considered as moving the edge position backward. Furthermore, the edge correction operation in this example can also be considered as adjusting the pixels representing the image to be printed. Furthermore, the edge correction processing operation performed in this example can also be considered as an example of setting the pixel values ​​of pixels within a predetermined width range from the edge to non-ejection values. Furthermore, the operation of the RIP processing unit 14 in the edge correction processing can also be considered as performing the following image processing operation: changing the pixel values ​​of pixels within a predetermined number of pixels from the boundary of the edge to be corrected, and which are set with ejection values ​​as pixel values, to non-ejection values.

[0067] Furthermore, in edge correction processing, it is conceivable that if only edge correction is performed on thin lines, the lines may disappear due to the correction. Therefore, in this example, the RIP processing unit 14 also detects the width of the area to be corrected and performs edge correction based on the width, thereby correcting the edges so that the lines do not disappear due to the correction. More specifically, in edge correction processing, the RIP processing unit 14 performs image processing on grayscale images for edges that correspond to lines with a preset line width or less among the edges detected in the edge detection processing, so that these lines do not disappear due to edge correction. With this configuration, edge correction can be performed more appropriately. Examples of edge correction for lines of various widths will be explained in more detail below.

[0068] Figure 6 An example of edge correction is shown. Figure 6 Examples (a) through (d) show edge corrections performed on lines of various widths. Figure 6 In (a) through (d), the left-hand image shows a portion of the pixels in the grayscale image before edge correction processing. The right-hand image shows a portion of the pixels in the grayscale image after edge correction processing. Furthermore, in the left-hand image, the thick solid line indicates the location of the edges detected by edge detection. In the right-hand image, the thick dashed line is drawn at the same position as the thick solid line in the left-hand image.

[0069] More specifically, Figure 6Figure (a) shows an example of edge correction performed on a line with a width of five pixels. In this case, the RIP processing unit 14 changes the pixel value of a region of one pixel along the edge to a non-ejection value by performing the edge correction processing described above. Therefore, the line after edge correction processing is reduced by 1 pixel on one side and 1 pixel on the other side of its five-pixel width, thus becoming a line with a width of three pixels, as shown in the figure on the right. In addition, in this case, 1 pixel is also reduced at the top along the length of the line. Figure 6 Figure (b) shows an example of edge correction performed on a line with a width of three pixels. In this case, during the edge correction process, the RIP processing unit 14 changes the pixel value of a region along the edge (one pixel) to a non-ejection value. Therefore, the line after edge correction is reduced by one pixel on one side and one pixel on the other side of its three-pixel width, thus becoming a line with a width of one pixel, as shown in the right-hand figure. Additionally, in this case, one pixel is also reduced at the top along the length of the line.

[0070] Furthermore, as can be understood from the above explanation, the RIP processing unit 14 reduces the width of lines and areas with greater width by performing edge correction in the same manner as described above. However, it is conceivable that if the same edge correction is performed on narrower lines, the lines would disappear due to the correction. More specifically, for example, when... Figure 6 In cases shown in (a) and (b), when edge correction is performed on lines with a width of less than 2 pixels, the pixel values ​​of all pixels across the entire width are changed to non-ejection values, thus causing the line to disappear.

[0071] Therefore, as explained above, in this example, the RIP processing unit 14 performs image processing on the grayscale image in a manner that prevents the lines from disappearing due to edge correction, for edges generated corresponding to lines below a preset line width. In this case, the image processing to prevent the lines from disappearing can be considered as performing image processing in a manner that retains at least 1 pixel in the width direction. Furthermore, regarding the retained pixels, it can be considered as retaining pixels whose pixel values ​​are ejection values. More specifically, in this example, as... Figure 6 As shown in (c) and (d), the edge correction processing for lines and regions with a width of less than two pixels is different from the edge correction processing for lines and regions with a width of more than three pixels.

[0072] Figure 6Figure (c) illustrates an example of edge correction performed on a line with a width of two pixels. In this case, during the edge correction process, the RIP processing unit 14 changes the pixel value of a region of one pixel along one side of the edge in the width direction of the line to a non-ejection value. Therefore, the line after edge correction is reduced by only one pixel on one side of the two-pixel width, thus becoming a line with a width of one pixel, as shown in the right-hand figure. Furthermore, in this case, one pixel is also reduced at the top in the length direction of the line. Figure 6 Figure (d) shows an example of edge correction performed on a line with a width of one pixel. In this case, the RIP processing unit 14 does not perform correction related to the width direction of the line during edge correction processing. Therefore, as shown in the right-hand figure, the line after edge correction processing becomes a line with a width of one pixel. Furthermore, in this case, the top 1 pixel is reduced in the length direction of the line. According to this example, even in cases such as printing images containing thin lines, edge correction processing can be performed more appropriately. Furthermore, this allows for a more appropriate improvement in the quality of the printed image.

[0073] Next, supplementary explanations and descriptions of variations related to the structures described above will be provided. The inventors of this application have actually performed the edge correction processing described above to print various images, thereby confirming the effectiveness of the edge correction processing. Figure 8 This diagram illustrates the effect of edge correction processing, comparing the printing results after edge correction processing with those after non-edge correction processing to demonstrate the printing of images containing cutout characters of various sizes. In the diagram, the upper photograph shows the printing result after edge correction processing as described above. This printing result can be considered as showing the result after one-pixel thinning. The lower photograph shows the printing result after printing without edge correction processing. Through their comparison, it can be clearly confirmed that higher quality printing can be achieved by performing edge correction processing. Furthermore, although the illustrations are omitted, the inventors of this application, in addition to... Figure 8 In addition to the examples shown, various images, such as those containing fine lines, were actually printed, thus confirming that the printing quality can be appropriately improved through edge correction processing.

[0074] Furthermore, as can be understood from the above explanation, the specific actions of edge correction processing are not limited to those described above, and various changes can be made. Figure 7 This is a diagram illustrating a variation of edge correction processing. Figure 7(a) and (b) show examples of changing the range of pixel values ​​in a modified example of edge correction processing. In the above, regarding edge correction processing, the example of changing the pixel value of a single pixel along the edge to a non-ejection value was mainly described. However, the range of pixel values ​​changed in edge correction processing is not limited to the examples described above, and various changes can be made. For example, in edge correction processing, the RIP processing unit 14 can also change the pixel values ​​of pixels within a range of two or more pixels wide along the edge (e.g., a range of about 2 to 3 pixels) to non-ejection values. More specifically, for example in… Figure 7 In (a), regarding the case where the pixel values ​​of two pixels along the edge are changed to non-ejection values, an example of the range of pixel values ​​that can be changed during edge correction processing is shown. Furthermore, regarding the width of the pixel values ​​that can be changed during edge correction processing, it is possible to determine this based on, for example, the relationship between the size of the ink dots actually formed during printing and the resolution. If configured in this way, edge correction can be appropriately performed according to the size and resolution of the ink dots, for example.

[0075] Furthermore, regarding the width of the range of pixel values ​​that can be changed during edge correction processing, for example, the width can differ between the edges of a line or region on one side and the edges on the other side. More specifically, for example, in... Figure 7 In (b), an example is shown where the pixel values ​​of two pixels along the edge are changed to non-ejection values ​​on one side of the line, and the pixel value of one pixel along the edge is changed to a non-ejection value on the other side of the line and in other parts. Even in this configuration, edge correction can be performed appropriately.

[0076] Furthermore, regarding edge correction processing described above, the action of changing the pixel values ​​of all pixels within a specified width along the edge to non-ejection values ​​was primarily explained. This action can be considered as deleting all points within a specified width from the edge. Additionally, depending on the required printing quality, it is also possible to select a subset of pixels within the specified width along the edge and change only the pixel values ​​of the selected pixels to non-ejection values.

[0077] Furthermore, as explained above, edge detection processing can also consider detecting edges within a pre-selected target area. In this case, edge correction processing can consider correcting only the edges detected within the selected target area. With this configuration, by selecting the areas to be corrected, edge correction can be performed more appropriately, following the user's intentions. Additionally, in this case, for example, it is possible to select target areas that correspond to parts important for representing fine lines, such as areas representing characters, for edge detection and correction.

[0078] Furthermore, in this case, it is possible to consider using an auxiliary image for selecting the target portion, in addition to multiple grayscale images generated in the plate separation process corresponding to the multiple colors of ink used in the printing execution unit 12. In this case, the auxiliary image can be considered, for example, an image composed of pixels with auxiliary values ​​set for selecting the target portion. More specifically, in this case, the RIP processing unit 14 determines the target portion to be selected based on data representing the grayscale image corresponding to the ink used in the printing execution unit 12 and auxiliary data representing the auxiliary image. Furthermore, in this case, the grayscale image corresponding to the ink used in the printing execution unit 12 can be considered an image with values ​​set for color representation, i.e., color representation values, for each pixel. Furthermore, the auxiliary image can be considered an image with auxiliary values ​​set for each pixel, where the auxiliary values ​​have a different purpose than the color representation values. Furthermore, in this case, the RIP processing unit 14 considers the portion consisting of pixels in the grayscale image corresponding to the ink used in the printing execution unit 12, and pixels corresponding to pixels in the auxiliary image that have been set with a predetermined auxiliary value, as the target portion for detection, and detects edges located within this target portion. With this configuration, the target portion can be easily and appropriately selected.

[0079] Furthermore, as can be understood from the above explanation, auxiliary data can be considered, for example, as image data representing image data with auxiliary values ​​set for pixels. As such auxiliary data, for example, channels (such as alpha channels) prepared separately from the color channels in data representing a color image with multiple color channels corresponding to multiple colors can be considered. More specifically, in this case, during the plate separation process, the RIP processing unit 14 generates multiple grayscale images corresponding to the inks of each color used in the printing execution unit 12, and auxiliary data corresponding to these grayscale images, based on the color image data containing the channels corresponding to these auxiliary data. Furthermore, more specifically, in this case, during the plate separation process, the RIP processing unit 14 generates image data containing multiple color channels corresponding to these multiple grayscale images, and channels representing the auxiliary data. Then, in the edge detection process, the RIP processing unit 14 identifies the selected target portion based on these multiple grayscale images and the auxiliary data. Then, edge detection is performed on the selected target portion. If configured in this way, edges contained in a portion of the image can be appropriately detected.

[0080] Furthermore, the selection of the target portion can also be performed using methods different from those described above. For example, the target portion can be selected based on user instructions received using an input device such as a mouse. In this case, range selection processing can be performed in the RIP processing unit 14, in which the user receives an instruction to select a range of a portion of an image, such as a grayscale image generated in the page splitting process. In the range selection processing, for example, the user may receive an instruction to select a range of a portion of another image corresponding to the grayscale image. Additionally, in the edge detection processing, the portion of pixels in the grayscale image that falls within the range selected by the user in the range selection processing is considered a target portion distinguished from other portions of the image, and edges within this target portion are detected. With this configuration, the selection of the target portion can be performed easily and appropriately.

[0081] Furthermore, as described above, in this example, the RIP processing unit 14 performs edge detection and edge correction processing on the grayscale image corresponding to each color ink used in the printing execution unit 12. Regarding this, in principle, considering only edge correction, it is also possible to consider edge detection and correction on the color image before plate separation, or on the binary bitmap generated through quantization processing. However, when performing edge detection and correction on the color image, it is necessary to separately calculate the amount of ink ejected at each pixel position to determine the correction amount, which raises concerns about the complexity of the correction process. Additionally, when performing edge detection and correction on the binary bitmap, the ejection positions of the ink are discretely set due to quantization processing, which raises concerns about the difficulty in detecting edges. In contrast, when performing edge detection and edge correction processing on the grayscale image corresponding to each color ink, this problem does not occur, and edge detection and correction can be performed more appropriately.

[0082] Furthermore, in this case, it is possible to perform edge detection and edge correction processing on the grayscale images corresponding to all the colors of ink used in the printing execution unit 12. More specifically, as explained above, when inks of each color of YMCK are used in the printing execution unit 12, it is possible to perform edge detection and edge correction processing on the grayscale images of these four colors. If configured in this way, the printing quality can be improved more appropriately. In addition, when inks other than the colors of YMCK (e.g., spot color inks) are also used in the printing execution unit 12, it is possible to use the grayscale image corresponding to that color when generating RIP generation data, and perform edge detection and edge correction processing on that grayscale image as well.

[0083] Furthermore, in variations of the action of generating RIP generation data, it is also possible to consider performing edge detection and edge correction processing only on a portion of the inks of each color used in the printing execution unit 12. In this case, it is preferable to perform edge detection and edge correction processing on at least colors with easily noticeable edges, such as K-color (black) ink. Moreover, in this case, it is more preferable to perform edge detection and edge correction processing not only on K-color but also on any color other than K-color.

[0084] Furthermore, as explained above, the RIP processing unit 14 can be, for example, a computer or similar device that executes a program for RIP processing. In this case, the program can be considered as an example of a program for generating ejection position data. Furthermore, the RIP processing unit 14 can be considered to operate as an ejection data generation device according to the program. Additionally, in this case, each part of the RIP processing unit 14 can be considered to function as a part of an ejection data generation device.

[0085] Furthermore, in this case, it can be assumed that each part of the computer used as the RIP processing unit 14 (e.g., the CPU, etc.) is being used. Figure 2 The processing units described above perform their functions. Furthermore, the RIP processing unit 14 can also be considered to have such processing units. More specifically, in this case, the RIP processing unit 14 can be considered to have an image acquisition processing unit, a resolution transformation processing unit, a page separation processing unit, an edge detection processing unit, an edge correction processing unit, and a RIP generation data generation unit, etc. Furthermore, in this case, the RIP generation data generation unit can be considered an example of an ejection position data generation processing unit. Additionally, the RIP generation data generation unit can be considered to have a quantization processing unit and a command processing unit.

[0086] Furthermore, the edge correction processing described above primarily involves changing the pixel values ​​of at least a portion of pixels within a defined range along the edge to non-ejection values. Moreover, this edge correction processing can also be considered as performing image processing to correct the edges by reducing the amount of ink ejected from at least a portion of the ejection position of the inkjet head for depicting the edges detected in the edge detection processing. Furthermore, as such edge correction processing, it is also possible to consider performing edge correction processing using methods different from those described above.

[0087] More specifically, as explained above, in a modified structure of the printing execution unit 12, inkjet heads for each color of ink can also be considered as inkjet heads that eject droplets of various capacities. Furthermore, in this case, edge correction processing can be performed to reduce the capacity of ink droplets ejected to at least a portion of the ejection positions near the edge. Additionally, in this case, for the grayscale image generated during the plate separation process, instead of changing the pixel values ​​of pixels within a defined range along the edge detected in the edge detection process from ejection values ​​to non-ejection values, edge correction processing can be performed by changing the hue value of the pixel to a hue value closer to the hue value of the non-ejection value. In this case, the ejection value whose hue value is closer to the hue value of the non-ejection value can be considered as a hue value among the hue values ​​set for each pixel of the grayscale image that is closer to the value used as the non-ejection value. Furthermore, such edge correction processing can also be considered as a correction process that reduces the size of ink dots formed at at least a portion of the ejection positions near the edge. Even with this configuration, the quality of printing performed in the printing execution section 12 can be appropriately improved.

[0088] Industrial availability

[0089] This invention can be appropriately used in ejection position data generation methods.

[0090] Explanation of reference numerals in the attached figures

[0091] 10: Printing system; 12: Printing execution unit; 14: RIP processing unit; 50: Media; 102: Inkjet head; 104: Tablet; 106: Main scan drive unit; 108: Sub-scan drive unit; 110: Control unit; 202: Pixel; 302: Dot.

Claims

1. A method for generating ejection position data, used to generate ejection position data, wherein the ejection position data is data representing the ejection position of ink ejected from an inkjet head in a printing apparatus, the method for generating ejection position data being characterized by performing the following processing: Edge detection processing, based on image data representing an image printed in the printing apparatus, i.e., processing object data, detects edges for at least a portion of the image; Edge correction processing: performing image processing on the image to correct the edges detected in the edge detection processing; as well as The ejection position data generation process generates the ejection position data in a manner that reflects the result of the image processing in the edge correction process. The processing object data refers to the image data composed of pixels corresponding to the ejection position. The processing object data is set with non-ejection values ​​or ejection values ​​as pixel values ​​for each pixel. The non-ejection value indicates that ink is not ejected at the corresponding ejection position, and the ejection value is a value other than the non-ejection value. In the edge detection process, the edge is detected by detecting the adjacent positions of pixels with the set non-ejection value and pixels with the set ejection value. In the edge correction process, for at least a portion of the ejection positions from the inkjet head where ink is ejected to depict the edges detected in the edge detection process, the pixel value of the corresponding pixel is changed to the non-ejection value, thereby performing the image processing for edge correction. The processing target data is data in the form of data that can select a portion of the image as a target portion to distinguish it from other portions. In the edge detection process, the edges located within the pre-selected target portion are detected. In the edge detection process, Auxiliary data is used to represent an image in which auxiliary values ​​are set for each pixel, i.e., auxiliary images. These auxiliary values ​​have a different purpose than the values ​​set for representing color. The portion of the pixels in the image represented by the processing object data that corresponds to the pixels in the auxiliary image that are set with a predetermined auxiliary value is regarded as the target portion as the detection object, and the edge in the target portion is detected.

2. The ejection position data generation method according to claim 1, characterized in that, In the edge correction process, the following image processing is performed: the pixel value of a pixel that is within a specified number of pixels from the boundary of the edge to be corrected, and which is set with the ejection value as the pixel value, is changed to the non-ejection value.

3. The method for generating ejection position data according to claim 1 or 2, characterized in that, In the edge correction process, the image processing is performed on the image such that the edges generated in the edge detection process that correspond to lines below a preset line width do not disappear due to the edge correction.

4. The ejection position data generation method according to claim 1 or 2, characterized in that, The printing apparatus is a color printer that uses multiple colors of ink for color printing. The ejection position data generation method also performs the following processing: Image acquisition processing, acquiring color image data, said color image data being data representing a color image printed in the printing apparatus; and The plate separation process is a process of generating grayscale images corresponding to each color of the plurality of inks used in the printing apparatus. This is achieved by separating the color image according to each color of the plurality of inks to generate grayscale images corresponding to those colors. The data used for processing includes data representing grayscale images corresponding to each of the colors.

5. The method for generating ejection position data according to claim 1 or 2, characterized in that, The process also includes range selection processing, in which the user receives an instruction to select a range within the image. In the edge detection process, the portion of pixels in the image represented by the processing object data that is within the range selected by the user in the range selection process is regarded as a target portion that is distinguishable from other portions in the image, and the edge located in the target portion is detected.

6. An ejection position data generating apparatus for generating ejection position data, wherein the ejection position data is data representing the ejection position of ink ejected from an inkjet head in a printing apparatus, the ejection position data generating apparatus being characterized by comprising: An edge detection processing unit detects edges for at least a portion of an image based on image data representing an image printed in the printing apparatus, i.e., processing object data. An edge correction processing unit performs image processing on the image to correct the edges detected by the edge detection processing unit; as well as The ejection position data generation and processing unit generates the ejection position data in a manner that reflects the result of the image processing in the edge correction processing unit. The processing object data refers to the image data composed of pixels corresponding to the ejection position. The processing object data is set with non-ejection values ​​or ejection values ​​as pixel values ​​for each pixel. The non-ejection value indicates that ink is not ejected at the corresponding ejection position, and the ejection value is a value other than the non-ejection value. The edge detection processing unit detects the edge by detecting the adjacent positions of pixels with the set non-ejection value and pixels with the set ejection value. The edge correction processing unit changes the pixel value of the corresponding pixel to the non-ejection value for at least a portion of the ejection positions from the inkjet head for depicting the edges detected by the edge detection processing unit, thereby performing the image processing for correcting the edges. The processing target data is data in the form of data that can select a portion of the image as a target portion to distinguish it from other portions. The edge detection processing unit detects the edges located within the pre-selected target portion. The edge detection processing unit uses auxiliary data representing an image, i.e., an auxiliary image, where auxiliary values ​​are set for each pixel. These auxiliary values ​​have a different purpose than the values ​​set for representing color. The edge detection processing unit considers the portion of the pixels in the image represented by the processing object data that corresponds to the pixels in the auxiliary image that have a predetermined auxiliary value set thereon as the target portion as the detection object, and detects the edge in the target portion.

7. The ejection position data generation device according to claim 6, characterized in that, The ejection position data generating device generates ejection position data for color printing using inks of multiple colors. The ejection position data generation device also includes: An image acquisition processing unit acquires color image data, which represents data of a color image printed in the printing apparatus; and The plate separation processing unit is a processing unit that performs the process of generating grayscale images corresponding to each color of the plurality of inks used in the printing apparatus. The plate separation processing unit generates grayscale images corresponding to each color by separating the color image according to each color of the plurality of inks. The edge detection processing unit detects edges for at least a portion of the grayscale image based on image data representing the grayscale image corresponding to each color, i.e., the processing object data. The edge correction processing unit performs image processing on the grayscale image to correct the edges detected by the edge detection processing unit.

8. A computer program product comprising a program that causes a computer to generate ejection position data, the ejection position data being data representing the ejection position of ink ejected from an inkjet head in a printing apparatus, the program being characterized in that it causes the computer to perform the following processing: Edge detection processing, based on image data representing an image printed in the printing apparatus, i.e., processing object data, detects edges for at least a portion of the image; Edge correction processing: performing image processing on the image to correct the edges detected in the edge detection processing; as well as The ejection position data generation process generates the ejection position data in a manner that reflects the result of the image processing in the edge correction process. The processing object data refers to the image data composed of pixels corresponding to the ejection position. The processing object data is set with non-ejection values ​​or ejection values ​​as pixel values ​​for each pixel. The non-ejection value indicates that ink is not ejected at the corresponding ejection position, and the ejection value is a value other than the non-ejection value. In the edge detection process, the edge is detected by detecting the adjacent positions of pixels with the set non-ejection value and pixels with the set ejection value. In the edge correction process, for at least a portion of the ejection positions from the inkjet head where ink is ejected to depict the edges detected in the edge detection process, the pixel value of the corresponding pixel is changed to the non-ejection value, thereby performing the image processing for edge correction. The processing target data is data in the form of data that can select a portion of the image as a target portion to distinguish it from other portions. In the edge detection process, the edges located within the pre-selected target portion are detected. In the edge detection process, Auxiliary data is used to represent an image in which auxiliary values ​​are set for each pixel, i.e., auxiliary images. These auxiliary values ​​have a different purpose than the values ​​set for representing color. The portion of the pixels in the image represented by the processing object data that corresponds to the pixels in the auxiliary image that are set with a predetermined auxiliary value is regarded as the target portion as the detection object, and the edge in the target portion is detected.

9. The computer program product according to claim 8, characterized in that, The program causes the computer to generate ejection position data for color printing using multiple colors of ink, and the program also causes the computer to perform the following processing: Image acquisition processing, acquiring color image data, said color image data being data representing a color image printed in the printing apparatus; and The plate separation process is a process of generating grayscale images corresponding to each color of the plurality of inks used in the printing apparatus. This is achieved by separating the color image according to each color of the plurality of inks to generate grayscale images corresponding to those colors. In the edge detection process, edges are detected for at least a portion of the grayscale image based on image data representing the grayscale image corresponding to each color, i.e., the processing object data. In the edge correction process, the grayscale image is subjected to image processing to correct the edges detected in the edge detection process.

10. A computer-readable storage medium storing a computer program that, when executed by a processor, performs the ejection position data generation method according to any one of claims 1-5.

Images