Method for processing raster data for printing, system for processing raster data for printing, control program, recording medium

Abstract

This invention provides a raster data processing method that can improve printing accuracy when printing with inkjet inks. [Solution] The method for processing raster data for printing includes an acquisition step (S1) for acquiring raster data for printing, and a data editing step (S3) for performing editing processing to modify the raster data.

Description

Technical Field

[0001] The present invention relates to a method for processing raster data for printing, a system for processing raster data for printing, and the like.

Background Art

[0002] Large-scale printing using inkjet ink is suitable for printing small quantities of many varieties. In large-scale printing using inkjet ink, as the image data to be printed, mainly raster data obtained by subjecting data created in pdf format to RIP (Raster Image Processor) processing is used (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when performing large-scale printing using inkjet ink, there has been room for improvement in printing accuracy. In particular, in large-scale printing using water-based inkjet ink, the deterioration of the printing system has sometimes been remarkable.

[0005] One aspect of the present invention is in view of the above problems, and provides a raster data processing method capable of improving printing accuracy when performing printing using inkjet ink.

Means for Solving the Problems

[0006] In order to solve the above problems, a method for processing raster data for printing according to one aspect of the present invention includes an acquisition step of acquiring raster data for printing, and a data editing step of performing an editing process for changing the raster data.

[0007] Furthermore, the raster data processing system for printing includes an acquisition unit that acquires raster data for printing, and a data editing unit that performs editing processing to modify the raster data. [Effects of the Invention]

[0008] According to one aspect of the present invention, a raster data processing method and a raster data processing system for printing can be provided that can improve printing accuracy when printing using inkjet ink. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram showing a conventional data processing flow and the raster data processing flow of the present invention. [Figure 2] This is a schematic diagram showing a raster data processing system according to one embodiment of the present invention. [Figure 3] This is a functional block diagram of a raster data processing device according to one embodiment of the present invention. [Figure 4] This flowchart shows an example of the data editing process flow of a raster data processing system according to one embodiment of the present invention. [Figure 5] This is a functional block diagram of a raster data processing device according to one embodiment of the present invention. [Figure 6] This flowchart shows an example of the data editing process flow of a raster data processing system according to one embodiment of the present invention. [Figure 7] This flowchart shows an example of a process for detecting an area to be edited by a raster data processing system according to one embodiment of the present invention. [Figure 8] This image shows 1-bit raster data for black ink ejection before editing processing, according to Example 1 of the present invention. [Figure 9] This image shows 1-bit raster data for cyan ink ejection before editing processing, according to Example 1 of the present invention. [Figure 10]It is an editing process flowchart corresponding to bleeding according to an embodiment of the present invention. [Figure 11] It is an image subjected to the cutting process according to Example 1 of the present invention. [Figure 12] It is an image subjected to the inversion process according to Example 1 of the present invention. [Figure 13] It is an image subjected to the color tone selection process according to Example 1 of the present invention. [Figure 14] It is an image subjected to the density division process according to Example 1 of the present invention. [Figure 15] It is an image subjected to the contour line creation process according to Example 1 of the present invention. [Figure 16] There is an image showing 1-bit raster data for black ink ejection subjected to the editing process corresponding to bleeding according to Example 1 of the present invention. [Figure 17] There is an image showing 1-bit raster data for cyan ink ejection subjected to the editing process corresponding to bleeding according to Example 1 of the present invention. [Figure 18] It is an image showing 1-bit raster data for black ink ejection after the editing process. [Figure 19] It is an image showing 1-bit raster data for cyan ink ejection after the editing process. [Figure 20] It is an image showing the printing result according to Example 1 of the present invention. [Figure 21] It is an image showing the printing result according to Comparative Example 1 of the present invention. [Figure 22] It is an image showing 1-bit raster data for white ink ejection before the editing process according to Example 2 of the present invention. [Figure 23] It is an image showing data obtained by converting 1-bit raster data for white ink ejection before the editing process according to Example 2 of the present invention into 2-bit raster data and converting black pixels into gray pixels. [Figure 24] It is an image showing data obtained by density-dividing 1-bit raster data for black ink ejection before the editing process according to Example 2 of the present invention in the same procedure as step4 of Example 1 and extracting only the part in the high-density region. [Figure 25]An image showing data obtained by superimposing the black ink ejection raster data extracted only in the high-concentration region of FIG. 24 on the raster data for white ink ejection (gray background) of FIG. 23. [Figure 26] An image showing the printing result according to Example 2 of the present invention. [Figure 27] An image showing the printing result according to Comparative Example 2 of the present invention.

Mode for Carrying Out the Invention

[0010] 〔Embodiment 1〕 (Raster Data Processing System 100) In large-scale printing using inkjet ink, the printing accuracy of printed matter may be reduced due to ink bleeding, misalignment of the printing position, etc. Particularly in large-scale printing using inkjet ink with aqueous ink, the reduction of the printing system may become significant. Conventionally, as a method for improving the printing accuracy of printed matter, the use of an anchor coat on the substrate and the change of the printing settings of the printing apparatus have been carried out. However, when an anchor coat is used on the substrate, although ink bleeding is reduced, streaks occur in the printed matter, so a large amount of ink has to be used. Changing the printing settings of the printing apparatus requires a highly skilled person to change the settings of the apparatus based on visual inspection to correct the misalignment of the printing position. Also, since the printing settings are changed by visually checking the printing result, printing has to be performed many times, which takes both time and cost. In addition, since the printing settings are changed by visually checking the printing result, printing has to be performed many times, which takes both time and cost.

[0011] Figure 1 shows an overview of the conventional data processing flow for printing and the flow according to the present invention. In the data processing flow for printing, first, full-color vector data is converted to raster data by RIP processing. Printing is performed using the converted raster data. One method that can address both ink bleeding and misalignment of the print position is to edit the data before RIP processing (the vector data shown in Figure 1). However, this method requires the raster data creator to edit the file before RIP processing and then perform RIP processing again. This second RIP processing places a heavy burden on the raster data creator and is time-consuming. Conventionally, it has been common to edit the data before RIP processing, and the idea of ​​editing the print raster data itself had not been conceived.

[0012] On the other hand, the raster data processing system 100 according to one embodiment of the present invention, with a configuration described later, allows the raster data processing device 10 to directly edit the raster data after RIP processing, as shown in Figure 1. Since further RIP processing is not required, the printing accuracy of printed materials can be easily improved.

[0013] Here, an overview of the raster data processing system 100 according to one embodiment of the present invention will be described using Figure 2. Figure 2 is a schematic diagram showing an example of the configuration of the raster data processing system 100 according to one embodiment of the present invention.

[0014] As shown in Figure 2, the raster data processing system 100 comprises a raster data processing device 10 and a printer 50. The raster data processing system 100 may further include a raster data creator terminal 30. The raster data processing device 10 performs editing processing to modify the acquired raster data. The printer 50 prints using the edited raster data output by the raster data processing device 10. The raster data creator terminal 30 transmits raster data for printing to the raster data processing device 10. As shown in Figure 2, the raster data processing system 100 may be connected to the raster data creator terminal 30 and the raster data processing device 10 via a wide-area communication network 40.

[0015] In this specification, "raster data" means print data containing multiple pixels. Examples of data containing only raster data include TIFF format and JPG format. Among these, TIFF format data is preferred as print data for large-scale printing.

[0016] In one embodiment, the raster data may include one or more specific color data indicating the area to be coated with a specific color ink when printing using the raster data. The specific color is not particularly limited and may be B (black), C (cyan), M (magenta), Y (yellow), W (white), and mixtures thereof, which are commonly used in printing. The specific color data includes data indicating the specific color corresponding to each pixel point. The raster data may include two or more, three or more, or four or more types of specific color data. By including two or more types of specific color data in the raster data, ink bleeding and misalignment of the printing position are more likely to occur, so the raster data processing system 100 can improve printing accuracy.

[0017] The number of bits in the raster data is not particularly limited, but may be, for example, 1 to 8 bits. The number of bits in the raster data is preferably 1 to 3 bits, more preferably 2 to 3 bits.

[0018] The raster data may be printed by any method. In one embodiment, it is preferable that the raster data be printed by digital printing using inkjet ink. In the case of digital printing using inkjet ink, ink bleeding and misalignment of the print position are likely to occur in the printed material, so the raster data processing system 100 can improve the printing accuracy. The inkjet ink may be an aqueous inkjet ink. In this specification, aqueous inkjet ink refers to an inkjet ink in which water is one of the main solvents.

[0019] The aforementioned digital printing method is more preferably performed without using an anchor coat. Without an anchor coat, streaks are less likely to appear in the printed material, and ink consumption can be reduced.

[0020] The substrate used for the digital printing is not particularly limited and may be an absorbent substrate such as paper, or a low-absorbent substrate or non-absorbent substrate such as a metal substrate or a plastic substrate. Among these, a low-absorbent substrate or a non-absorbent substrate is more preferable.

[0021] When a low-absorbent or non-absorbent substrate is used as the substrate, ink bleeding and misalignment of the print position are likely to occur in the printed material, so the raster data processing system 100 can improve the printing accuracy.

[0022] As a plastic substrate used as a low-absorbency or non-absorbent substrate, it is preferable to use a poorly absorbent synthetic resin film such as PET (polyethylene terephthalate), PVC (polyvinyl chloride), or PP (polypropylene).

[0023] The inkjet printing method used for the aforementioned digital printing may be a multi-pass method or a single-pass method, but in light of the ability to perform high-speed printing, it is preferable to use a single-pass inkjet image forming method.

[0024] The printing device 50 included in the raster data processing system 100 is not particularly limited, but it is preferably a large-format printing press. Large-format printing presses employ a single-pass printing method to improve the productivity of printed materials. As a result, ink bleeding and misalignment of the printing position are more likely to occur. In addition, it is difficult to change the printing settings of large-format printing presses, and costs increase significantly when a large amount of ink is used, so the effects of editing raster data by the raster data processing device 10 tend to be greater. In this specification, a large-format printing press means a printing press with a total length of 3m or more (for example, 15m).

[0025] The resolution of the ejection head used for printing is preferably 600 dpi or higher, and more preferably 1200 dpi or higher. When an ejection head with a resolution of 600 dpi or higher is used, high-definition image printing becomes possible, but the distance between dots becomes smaller, making ink bleeding more likely, and thus the effects of editing the raster data by the raster data processing device 10 tend to be greater.

[0026] In one embodiment, the raster data processing device 10 and the printing device 50 may be connected via a wide-area communication network 40. Preferably, the raster data processing device 10 and the printing device 50 are connected via a local area network connection, LTE, etc., without going through an ISP. The devices are connected via communication or directly via a communication cable. It is preferable that the owner of the raster data processing device 10 and the owner of the printing device 50 are the same person, as this facilitates verification of the print results. With this configuration, the company performing the printing using the printing device 50 can edit the raster data, thus making it easier to improve print accuracy.

[0027] The raster data creator terminal 30 is not particularly limited to any terminal that the raster data creator may own, such as a laptop computer, smartphone, or tablet. The raster data creator terminal 30 may store data, including raster data, before RIP processing. The raster data creator terminal 30 may transmit raster data via a wide-area communication network 40, or it may transmit raster data by directly connecting to the raster data processing device 10. In one embodiment, a computer-readable recording medium on which raster data is stored may be used instead of the raster data creator terminal 30.

[0028] The wide-area communication network 40 is not particularly limited and may include the Internet, telephone network, mobile communication network, CATV network, satellite communication network, etc. Furthermore, the wide-area communication network 40 may also be connected to a cloud server that stores raster data transmitted by the raster data creator terminal 30.

[0029] (Raster data processing device 10) The following describes the overview and effects of the raster data processing device 10. The raster data processing device 10 is a device that performs editing processing to make changes to the raster data described above.

[0030] Figure 3 is a functional block diagram showing an example of the configuration of the raster data processing device 10. The raster data processing device 10 includes a control unit 1 that controls all parts of the raster data processing device 10, a storage unit 2 that stores various types of data used by the raster data processing device 10, and an input unit 3 that accepts user input, but is not limited to this configuration. For example, the storage unit 2 may be an external device attached to the raster data processing device 10. Also, as described above, the raster data processing device 10 may be connected to a wide-area communication network 40.

[0031] Input unit 3 is for receiving various input operations from the user. Input unit 3 may be, for example, a keyboard, mouse, touch panel, etc. Input unit 3 may be used to specify the area of ​​raster data to be edited by the user, or to specify the type of processing to be performed on the raster data. Input unit 3 may also be used to operate the raster data processing device 10, or to select the raster data to be acquired by the acquisition unit 11.

[0032] <Control Unit 1> The control unit 1 will now be described. The control unit 1 includes an acquisition unit 11, a data editing unit 12, a region designation unit 13, and an output control unit 14. Furthermore, some of the blocks included in the control unit 1 may be assigned to other devices that can communicate with the raster data processing device 10, and those blocks may be omitted from the control unit 1. For example, the functions of the output control unit 14 may be assigned to other devices. In this case, the raster data processing device 10 may output the edited raster data processed by the data editing unit 12 using the other device.

[0033] The acquisition unit 11 acquires raster data output from the raster data creator terminal 30. The acquisition unit 11 may acquire raster data one by one, or it may acquire multiple raster data at once. The acquisition unit 11 stores the acquired raster data in the storage unit 2. That's good too.

[0034] The data editing unit 12 performs editing operations to modify the raster data. The changes that the data editing unit 12 can make to the raster data are not particularly limited. Examples of editing operations performed by the data editing unit 12 include the following operations on the area of ​​the image to be processed included in the raster data. (1) Rotation. (2) Reverse. (3) Trimming. (4) Movement of pixel points (including movement of only pixel points of a specific color). (5) Changing the color density. The color density in the area to be processed is determined by the number of pixel points present in the area to be processed. (6) Changing the gray level of pixel point color. The pixel points whose gray level is changed may be limited to only those of a specific color. (7) Morphological processing of pixel points. The pixel points to be subjected to morphological processing may be limited to only those of a specific color. Morphological processing includes at least one of dilation and stenosis. (8) A combination of (1) to (7) as described above. (9) Image compositing between images before and after editing. Image compositing may be performed by a logical expression. The logical expression includes at least one of AND, OR, AND / OR, and AND / NOT.

[0035] In this specification, "gray level" refers to a value corresponding to the volume of a liquid droplet. In other words, the "gray level for the color of a pixel point" is a value that determines the volume of a liquid droplet applied to the area corresponding to a pixel point when printing using raster data containing a pixel point. For example, if the raster data has 1 bit, two values ​​(2 to the power of 1) can be set as the gray level. Specifically, the gray level has values ​​corresponding to white (non-ejection) and black (ejection). During printing, the color corresponding to the gray level is applied to the area corresponding to the pixel point. For example, if the raster data has 2 bits, four values ​​(2 to the power of 2) can be set as the gray level. Specifically, the gray level has values ​​corresponding to white (non-ejection), light gray (small droplet), dark gray (medium droplet), and black (large droplet). During printing, the color corresponding to the gray level is applied to the area corresponding to the pixel point.

[0036] The volume of inkjet ink droplets ejected by the ejection head can be adjusted by the number of pulses during ink ejection. Specifically, the number of pulses can be adjusted according to the gray level value, and the volume of the droplets can be adjusted according to the value of the pulses. For example, if the number of bits in the raster data is 2 bits, the gray level value is 0 to 3, so the number of pulses can be adjusted between 0 and 3. When the number of pulses is 1, the ejection volume is 10 pL, resulting in a small light gray droplet. When the number of pulses is 2, the ejection volume is 20 pL, resulting in a medium dark gray droplet. When the number of pulses is 3, the ejection volume is 30 pL, resulting in a large black droplet. These settings are just examples, and the combination of the gray level value and the corresponding pulse number value is not limited to the above combinations.

[0037] The data editing unit 12 may perform editing on only a specific area of ​​the image included in the raster data, or it may perform editing on the entire image, or it may change the area to be edited depending on the type of processing.

[0038] The area designation unit 13 designates the areas where the data editing unit 12 will perform editing based on the information input from the input unit 3. The area designation unit 13 may designate only one area, or multiple areas. You may specify several areas, or you may specify the entire image contained in the raster data as the area. In one embodiment, the area specification unit 13 may specify an area where no editing processing will be performed. In one embodiment, the area specification unit 13 may further specify the type of processing to be performed by the data editing unit 12.

[0039] The output control unit 14 outputs the edited raster data output by the data editing unit 12 to the printing device 50. If the raster data processing device 10 is equipped with an output device such as a display, the output control unit 14 may output the edited raster data to that output device. Alternatively, the output control unit 14 may be another device that has output control functionality in addition to being a device that can acquire raster data. In this case, the raster data processing device 10 may transmit the edited raster data via the other device. In one embodiment, the output control unit 14 may further be equipped with a communication unit function.

[0040] <Storage section 2> Next, we will explain the memory unit 2. The memory unit 2 stores raster data 21 and edited raster data 22.

[0041] Raster data 21 is data output from the raster data creator terminal 30. Raster data 21 is RIP-processed data. In one embodiment, raster data 21 is RIP-processed data in TIFF format.

[0042] The edited raster data 22 is raster data that has been edited by the data editing unit 12. If the data editing unit 12 has performed multiple editing processes, the edited raster data 22 may include not only the raster data after the editing process is completed, but also the raster data corresponding to each editing process performed by the data editing unit 12. Furthermore, the edited raster data 22 may include raster data saved each time the editing process is performed a certain number of times (for example, two, three, or four times).

[0043] (Raster data processing method) A raster data processing method according to one embodiment of the present invention will be described with reference to Figure 4. Figure 4 is a flowchart showing an overview of the raster data processing method.

[0044] Step S1 is an acquisition step in which the acquisition unit 11 acquires raster data from the raster data creator terminal 30. In step S1, the acquisition unit 11 may further acquire the print result using the acquired raster data.

[0045] The raster data processing method may include step S2. Step S2 is a step in which the area designation unit 13 specifies the area to be edited. The area designated by the area designation unit 13 may be an area based on user input, or it may be the entire image contained in the raster data.

[0046] Step S3 is a data editing step in which the data editing unit 12 performs editing processing to make changes to a specified area in the raster data. In step S3, since the data editing unit 12 directly edits the raster data, it is possible to create edited raster data without performing RIP processing again. In step S3, if the raster data contains two or more types of specific color data, the data editing unit 12 may perform the above-described editing processing for each type of specific color data.

[0047] In step S3, the data editing unit 12 checks for possible ink bleeding of the same color, ink bleeding of different colors, misalignment of the print position, and smudging that may occur in the printed material when raster data is printed. Raster data is edited to reduce bleed, etc. In this specification, "same-color bleeding" means that when printing is done using ink of the same color, the ink in areas with high color density bleeds into areas with low color density of the same color. Also, in this specification, "different-color bleeding" means that when printing is done using ink of different specific colors, the ink in areas of a specific color bleeds into areas where ink of another specific color is present.

[0048] For example, when the data editing unit 12 reduces ink bleeding of the same color, it performs editing by reducing the number of pixel points at the boundary between areas with different densities of the same specific color in areas where the same specific color exists with different densities (i.e., dot density in the raster data). When reducing bleeding of different colors, it performs editing by reducing the number of pixel points in areas where different specific colors exist and the boundary between those different specific colors exists. When reducing misalignment of the print position, it performs editing by moving the position of pixel points only for the specific color where the misalignment occurs in the area where the misalignment occurs. When reducing streaks, it performs editing by changing the gray level of the pixel points in the area where streaks occur. Note that the editing may also be performed by converting the image to grayscale corresponding to a specific gray level, and then changing the gray level of the pixel points in the area where streaks occur. As a result of this editing, when ink is applied to the area where the gray level of the pixel points has been changed, the volume of droplets ejected from the head of the printing device increases, thus reducing streaks. Smudges tend to occur in specific areas, such as when white ink is applied to areas with a darker ink color. Therefore, by increasing the droplet volume only in the areas where smudges occur, it is possible to reduce smudges without increasing the drying load on the printed material.

[0049] The raster data processing method may include a step to check the output result between step S3 and step S4, if necessary. Specifically, if the raster data has two or more types of specific color data, the method may include a step to combine each of the edited specific color data.

[0050] Step S4 is an output step in which the output control unit 14 transmits (outputs) the edited raster data edited by the data editing unit 12 to the printing device 50.

[0051] According to a raster data processing method of one embodiment of the present invention, raster data after RIP processing can be directly edited. Therefore, the printing accuracy of printed materials can be improved without performing RIP processing again or adjusting the printing device.

[0052] [Embodiment 2] The following outline of a raster data processing device 10a according to another embodiment of the present invention will be described with reference to Figure 5. Figure 5 is a schematic diagram showing an example of the configuration of a raster data processing device 10a different from Embodiment 1. Matters that have already been described will be omitted.

[0053] <Control Unit 1a> The acquisition unit 11a may acquire, in addition to the raster data, the print result obtained by printing using the raster data. In one embodiment, the print result may be scanned data of the printed material, etc.

[0054] The detection unit 15 detects areas within the raster data that may cause ink bleeding, misalignment of print position, etc., in the printed material obtained by printing using the raster data acquired by the acquisition unit 11a. The detection unit 15 transmits the detected areas to the data editing unit 12a. The detection unit 15 may detect only one area within the raster data that the data editing unit 12a will edit, or it may detect multiple areas. The detection unit 15 does not perform editing on areas. Further detection of the region is also possible. The detection unit 15 may store the detected region data, which is data indicating the detected region, in the storage unit 2a.

[0055] In one embodiment, if the raster data includes two or more specific color data, the detection unit 15 may detect a region for each specific color data, or it may detect a region in the raster data that includes multiple specific color data. The detection unit 15 may further detect the density (i.e., the density of points present in the raster data) distribution for at least one or more specific colors among the specific color data included in the raster data. More specifically, it may detect a region where a boundary exists between a part with high density and a part with low density of the specific color.

[0056] The data editing unit 12a performs editing on the area detected by the detection unit 15 included in the raster data. The editing process performed by the data editing unit 12a on the raster data is as described above. In one embodiment, the data editing unit 12a may perform editing based on the density distribution of a specific color detected by the detection unit 15. Furthermore, if the acquisition unit 11a has acquired the print result, the data editing unit 12a may perform processing based on the difference between the characteristics of the area to be edited and the characteristics of the area of ​​interest, which is the area in the print result corresponding to that area.

[0057] <Storage section 2a> The storage unit 2a may also store detected region data 23. The detected region data 23 is data indicating the region contained in the raster data that has been detected by the detection unit 15. Based on the region indicated by the detected region data 23, the data editing unit 12a performs editing processing.

[0058] (Raster data processing method) A raster data processing method according to another embodiment of the present invention will be described with reference to Figure 6. Figure 6 is a flowchart showing an overview of the other raster data processing method.

[0059] In step S1, the acquisition unit 11a may acquire, in addition to the raster data, the print result obtained by printing using the raster data.

[0060] In step S2a, the detection unit 15 detects the areas to be edited within the raster data. The detection unit 15 may detect only one area to be edited, or it may detect multiple areas.

[0061] In step S2a, if the raster data includes specific color data, the detection unit 15 may further detect the density distribution of at least one specific color from the specific color data included in the raster data.

[0062] If the acquisition unit 11a has further acquired print results using raster data, in step S2a, the detection unit 15 may further detect areas where there is a difference between a specific area included in the raster data and the characteristics of the area of ​​interest, which is the area in the print result corresponding to that area.

[0063] In step S3a, the data editing unit 12a performs editing processing to modify the area detected by the detection unit 15. Step S3a is substantially the same as step S3, except that the area in which the data editing unit 12a performs editing processing is the area detected by the detection unit 15.

[0064] In one embodiment, if the acquisition unit 11a further acquires a print result using raster data in step S1, the data editing unit 12 may further perform processing based on the difference between the characteristics of the region detected by the detection unit 15 and the characteristics of the region of interest, which is the region in the print result corresponding to that region. Specifically, if the data editing unit 12 finds that there is a misalignment of the print position of the printed image, ink bleeding, etc. in the region of interest, it may perform raster data editing processing to eliminate these misalignments and bleeding, etc.

[0065] In one embodiment, if the detection unit 15 further detects a density distribution for at least one specific color in step S2a, the data editing unit 12 may perform editing processing based on the density distribution in step S3a. Specifically, editing processing may be performed to change the density of the specific color in a region that includes the boundary between a part of the specific color with high density and a part of the specific color with low density.

[0066] With the above configuration, the detection unit 15 specifies the area in which the data editing unit 12 performs editing, allowing for more accurate editing and improved printing accuracy.

[0067] (Region detection method) A method for detecting an area to be edited according to one embodiment of the present invention will be described with reference to Figure 7. Figure 7 is a flowchart showing an overview of an example of an area detection method. In Figure 7, the detection unit 15 detects the density distribution of a specific color contained in the raster data, and further detects the area to be edited based on the detected density distribution. However, the detection method shown in Figure 7 is just one example, and the method by which the detection unit 15 detects an area is not limited to the following.

[0068] In step S11, the detection unit 15 detects the density distribution of one or more specific color data contained in the raster data. The density distribution detection may be performed, for example, by morphological transformation. In step S11, the density distribution of a specific color may be represented in two or more stages (for example, two stages: light and dark), three or more stages (for example, three stages: light, normal and dark), or even more stages (for example, percentages). It is preferable that the density distribution be represented in three or more stages in order to improve the printing accuracy of the printed material.

[0069] In step S12, the detection unit 15 divides the specific color data according to the detected density distribution and creates multiple divided specific color data. The specific color data may be divided according to the steps described above, or it may be divided into steps within a certain range (for example, three steps of density 0-30%, 31-70%, and 71-100%).

[0070] In step S13, the detection unit 15 detects overlapping areas between multiple divided specific color data. In addition to the overlapping areas, the detection unit 15 may further detect the boundaries of regions with different densities. In step S13, the detection unit 15 may further detect overlapping areas between multiple specific color data. Overlapping areas between specific color data can be detected by morphologically transforming each specific color data and then combining them.

[0071] In step S14, the detection unit 15 outputs (sends) the detected duplicates to the data editing unit 12. The data editing unit 12 then performs editing based on the output differences.

[0072] According to the above configuration, it is possible to detect areas where ink bleeding of the same color or different colors may occur. Therefore, by editing these areas, the printing accuracy of the printed material can be improved.

[0073] [Examples of implementation using software] The function of the raster data processing device (hereinafter referred to as "the device") is a program that causes the device to function as a computer, and can be realized by a program that causes the computer to function as each control block of the device (particularly each part included in the control unit 1).

[0074] In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., memory) as hardware for executing the program. By executing the program using this control device and storage device, the functions described in each of the embodiments are realized.

[0075] The above program may be recorded on one or more computer-readable recording media, not temporary ones. These recording media may or may not be provided by the above device. In the latter case, the program may be supplied to the above device via any wired or wireless transmission medium.

[0076] Furthermore, some or all of the functions of each of the above control blocks can also be realized by logic circuits. For example, an integrated circuit in which logic circuits functioning as each of the above control blocks are formed is also included in the scope of the present invention. In addition, it is also possible to realize the functions of each of the above control blocks by, for example, a quantum computer.

[0077] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0078] 〔summary〕 [1] A method for processing raster data for printing, comprising: an acquisition step of acquiring raster data for printing; and a data editing step of performing editing processing to modify the raster data.

[0079] [2] The method for processing raster data for printing according to aspect 2 of the present invention may include a detection step before the data editing step for detecting an area to be edited to modify the raster data, in accordance with aspect 1 of the present invention.

[0080] [3] The printing raster data processing method according to aspect 3 of the present invention, in aspect 1 or 2 of the present invention, the raster data may include one or more specific color data indicating areas to be coated with ink of a specific color when printing using the raster data. The printing raster data processing method according to claim 1.

[0081] [4] In the printable raster data processing method according to aspect 4 of the present invention, in any of aspects 1 to 3 of the present invention, the editing process may be performed for each specific color data in the data editing step.

[0082] [5] In the printing raster data processing method according to aspect 5 of the present invention, the number of bits of the raster data may be 1 to 8 bits in any of aspects 1 to 4 of the present invention.

[0083] [6] In any of embodiments 2 to 5 of the present invention, the method for processing raster data for printing according to aspect 6 of the present invention further detects the density distribution of at least one specific color among the specific color data included in the raster data, and in the data editing step, performs editing processing to modify the raster data based on the density distribution.

[0084] [7] The method for processing raster data for printing according to aspect 7 of the present invention is the same as the method according to aspects 2 to 6 of the present invention. In either case, the acquisition step may further acquire the print result using the raster data, and the data editing step may further perform processing based on the difference between the characteristics of the region and the characteristics of the region of interest, which is the region in the print result corresponding to that region.

[0085] [8] In the printable raster data processing method according to aspect 8 of the present invention, the raster data may be printed by digital printing using inkjet ink in any of aspects 1 to 7 of the present invention.

[0086] [9] In the printable raster data processing method according to aspect 8 of the present invention, in any of aspects 1 to 8 of the present invention, an anchor coat may not be used in the digital printing.

[0087]

[10] A raster data processing system for printing according to aspect 10 of the present invention comprises an acquisition unit for acquiring raster data for printing and a data editing unit for performing editing processing to modify the raster data.

[0088]

[11] The raster data processing system for printing according to aspect 10 of the present invention may further include a detection unit for detecting an area in which editing processing is performed to modify the raster data.

[0089]

[12] A control program according to aspect 12 of the present invention is a control program for causing a computer to function as a raster data processing system for printing according to aspect 10 or 11 of the present invention, wherein the computer functions as the acquisition unit, the detection unit, and the data editing unit.

[0090]

[13] The computer-readable recording medium according to aspect 13 of the present invention records the control program described in aspect 12 of the present invention. [Examples]

[0091] [Example 1] The printing was performed using a 1200dpi water-based inkjet printer capable of outputting black (B), cyan (C), magenta (M), yellow (Y), and white (W), and corona-treated PET as the substrate.

[0092] Figure 8 shows a 1-bit image data file (B.tif) for black (B) coating, and Figure 9 shows a 1-bit image data file (C.tif) for cyan (C) coating. In the images shown in Figures 8 and 9, black pixels represent "areas to be coated with ink," and white pixels represent "areas not to be coated with ink." All other pixels (M (magenta), Y (yellow), and W (white)) are treated as white pixels. Figure 10 shows the flow of each step in image processing. Each step is described in detail below. Figures 11-19 show the images processed at each step.

[0093] (Step 1. Cut) The area to be processed was extracted from the image using a cropping process. The extracted image (B_1_crop.tif) is shown in Figure 11.

[0094] (Step 2. Inversion process) The gray levels of the extracted image were inverted. In this case, since it was a 1-bit image, white pixels (1) were converted to black pixels (0), and black pixels (0) were converted to white pixels (1). The converted image (B_2_inv.tif) is shown in Figure 12.

[0095] (Step 3. Selecting the color tones that will cause bleeding) Black (B) was selected as the color tone that causes blurring, and the image shown in Figure 12 was saved as a reference image (ref.tif).

[0096] (Step 4. Concentration division) To avoid interfering with contour extraction in subsequent steps, the reference image was subjected to morphological processing by performing one dilation, two scalding, and one dilation operation in that order to remove areas with low dot density. Subsequently, the image after the morphological processing and the reference image were combined using an AND logic expression to obtain an image showing areas with high dot density. The obtained image showing high-density areas (ref_HD.tif) is shown in Figure 14. Also, the image of the low-density areas removed by the morphological processing is shown in Figure 13 (ref_LD.tif).

[0097] (Step 5. Creating the outline) The image shown in Figure 14 was subjected to dilation, and the image before dilation and the image after dilation were combined using an AND / NOT logic expression. The resulting contour image (outer.tif) was then processed. This is shown in Figure 15.

[0098] (Step 6. Synthesis) The contour image obtained above was subjected to an expansion process. Subsequently, the expanded image and the respective images (B_1_crоp.tif and C_1_crоp.tif) extracted from the raster data shown in Figures 8 and 9 by cropping were combined using an OR logic expression. Figure 16 shows the image (B_6.tif) with the same-color bleeding areas cropped. Figure 17 shows the image (C_6.tif) with the different-color bleeding areas cropped.

[0099] (Step 7. Confirmation) We confirmed that there were no problems with the resulting cropped images. We then pasted the images from Figures 16 and 17 onto the cropped positions of the images shown in Figures 8 and 9.

[0100] (Step.8. Save) The processed image was saved. The 1-bit image data for coating B (B_8_cоnv.tif) is shown in Figure 18. The 1-bit image data for coating C (CC_8_cоnv.tif) was also saved as Figure 19.

[0101] Figure 20 shows the printed output obtained after performing the above steps 1 to 8 on the entire image. No bleeding of the same or different colors was observed around the processed text or shapes.

[0102] [Comparative Example 1] Figure 21 shows the printed material obtained by printing using the same procedure as in Example 1, except that the image processing described in Steps 1-8 above was omitted. Both same-color and different-color bleeding were observed.

[0103] [Example 2] Figure 8 was prepared as 1-bit image data for black (B) coating, and Figure 22 was prepared as 1-bit image data for white (W) coating. In the images shown in Figure 8 and Figure 22, black pixels represent "areas to be coated with ink," and white pixels represent "areas not to be coated with ink." Note that all pixels in Figure 22 are black (to be coated). In other words, if Figure 22 is actually printed, it will be a solid white color. The images shown in Figure 8 and Figure 22 were processed using the following procedure. 1. Convert the 1-bit image data for W coating in Figure 22 to 2-bit image data, and the black pixels in the image The xels were converted to grayscale pixels. The converted image is shown in Figure 23. 2. The 1-bit image data for coating B shown in Figure 8 was processed in the same manner as in step 4 of Example 1, and only the areas with high dot density were extracted. The extracted image is shown in Figure 24. 3. Figures 23 and 24 were combined using an AND logic expression to obtain Figure 25. Figure 25 is data in which the gray background for W coating from Figure 23 is superimposed with the image data for B coating, which was extracted only from the high-density region of Figure 24.

[0104] After performing the image processing described above, the image data for coating B was printed, followed by the image data for coating W. The image for coating W was a grayscale image with 2-bit gray levels. For the image for coating W, large droplets (40 picoliters) were assigned to black pixels and medium droplets (30 picoliters) to gray pixels for printing. The results of the printing are shown in Figure 26. Figure 26 is an image of a portion of the printing results in Example 2 (the black square in the upper right of Figure 25, where ink W was applied after ink B) observed from the side where ink W was applied, and magnified 50 times using a digital microscope. From Figure 26, no unevenness caused by ink W was observed in the entire area, including the area to which ink B was applied.

[0105] [Comparative Example 2] Printing was performed without performing the image processing steps 1-3 described in Example 2. The image shown in Figure 22 was used as the 1-bit image data for W coating. Medium droplets (30 picoliters) were assigned to black pixels, and printing was performed. The printing result is shown in Figure 27. Figure 27 is an image of a portion of the printing result in Comparative Example 2 (the black square in the upper right of Figure 25, where W ink was applied after B ink), observed from the side where W ink was applied, and magnified 50 times using a digital microscope. White (W) streaks were observed on the high-density B (black) area.

[0106] Based on the above, it has been shown that, according to the raster data processing method of one embodiment of the present invention, the printing accuracy of printed materials can be improved by directly editing the raster data. [Explanation of symbols]

[0107] 10, 10a Raster Data Processing Device 11 Acquisition Department 12 Data Editorial Department 30 Raster data creator terminals 50 Printing device 100 Raster Data Processing Systems

Claims

1. Acquisition step to obtain raster data for printing, A data editing step involves performing an editing process to modify the raster data, A method for processing raster data for printing, including the processing of such data.

2. The data editing step includes a detection step to detect areas in the raster data where editing processing will be performed to make changes. The method for processing raster data for printing according to claim 1.

3. The raster data includes one or more specific color data indicating the areas to be coated with a specific color ink when printing using the raster data. The method for processing raster data for printing according to claim 1.

4. In the data editing step, the editing process is performed for each specific color data. The method for processing raster data for printing according to claim 1.

5. The number of bits in the aforementioned raster data is 1 to 8 bits. The method for processing raster data for printing according to claim 1.

6. In the detection step, the density distribution of at least one specific color among the specific color data included in the raster data is further detected. In the data editing step, editing is performed to modify the raster data based on the density distribution. The method for processing raster data for printing according to claim 2.

7. In the acquisition step described above, the print result using the raster data is further acquired, In the data editing step, further processing is performed based on the difference between the characteristics of the region and the characteristics of the region of interest, which is the region in the print result corresponding to that region. The method for processing raster data for printing according to claim 2.

8. The aforementioned raster data is printed by digital printing using inkjet ink. The method for processing raster data for printing according to claim 1.

9. In the aforementioned digital printing, an anchor coat is not used. The method for processing raster data for printing according to claim 8.

10. An acquisition unit for acquiring raster data for printing, A data editing unit performs editing processing to modify the raster data, Equipped with, A raster data processing system for printing.

11. The system further includes a detection unit that detects areas in the raster data where editing processing is performed to modify the data. The raster data processing system for printing according to claim 10.

12. A control program for causing a computer to function as a raster data processing system for printing according to claim 10, wherein the computer functions as the acquisition unit, the detection unit, and the data editing unit.

13. A computer-readable recording medium that stores the control program described in claim 12.

Images