Image processing device and image processing method

Abstract

To provide a technique for suppressing image quality deterioration and throughput degradation, while achieving high quality printing, despite that satellites associated with main droplets of ink discharged according to a scanning direction are scattered at a certain flight distance.SOLUTION: A ratio of pixels recorded by one or more recording elements included in a first recording element array out of a plurality of pixels included in a first edge region of a target object, is smaller than a ratio of pixels recorded by one or more recording elements included in a second recording element array. A ratio of pixels recorded by one or more recording elements included in the second recording element array out of a plurality of pixels included in a second edge region of the target object, is smaller than a ratio of pixels recorded by one or more recording elements included in the first recording element array.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to image processing technology. [Background technology]

[0002] Conventionally, there has been known an inkjet printing device that prints an image on a recording medium by ejecting ink from a printing head onto the recording medium while moving at least one of the recording head and the recording medium relatively to one another.

[0003] Among the inkjet methods, the bubble jet recording method (BJ method) uses a heating element to rapidly heat and vaporize ink, and the pressure of the generated bubbles causes ink droplets to be ejected from an orifice. The bubbles generated in a bubble jet recording head with this structure are cooled by the surrounding ink, and the ink vapor inside the bubbles condenses and returns to liquid, so the bubbles eventually disappear. Meanwhile, the ink consumed by ejection is refilled from an ink tank that stores ink via an ink supply path.

[0004] Immediately after ink is ejected from a nozzle equipped with a recording element, it forms a tail of ink that has not yet separated from the nozzle. After that, a main droplet begins to form ahead in the ejection direction, and when the main droplet overcomes the surface tension, it is separated into a main droplet and multiple sub-droplets (satellites), which then fly apart. Finally, the main droplet and multiple satellites land on the recording medium.

[0005] As in the example described above, when ink is ejected from each nozzle, in addition to the main droplet, multiple satellite droplets also land on the recording medium, causing image degradation, particularly in the edge regions of the image that are the boundaries between printed and non-printed areas.

[0006] In view of such problems, a technology has been proposed as disclosed in Patent Document 1. Patent Document 1 discloses a technology that, in a case where sub-droplets accompanying a main droplet of ejected ink scatter at a certain angle, can achieve high-quality lines and characters with sharp and clear edge areas by causing the satellites to land inside the pixel area formed by the main droplet when one of the nozzle rows is driven in accordance with the scanning direction of the carriage. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 3559737 Summary of the Invention [Problem to be solved by the invention]

[0008] However, as disclosed in Patent Document 1, when any one of the recording element arrays is driven in accordance with the scanning direction of the carriage, there are problems such as deterioration of image quality and degradation of throughput.

[0009] For example, the recording data used when recording a first print area in a first scanning direction is first recording data with a limited usage rate of the first nozzle row. Meanwhile, a second print area adjacent to the first print area in the recording paper transport direction is recorded in a second scanning direction that is the opposite scanning direction to the first scanning direction. The recording data used when recording the second print area in the second scanning direction is second recording data with a limited usage rate of the second nozzle row. Because different recording data is used on the recording medium in the recording paper transport direction, image uniformity between adjacent print areas decreases, causing degradation of image quality.

[0010] In addition, there is a problem that the processing time increases because two types of recording data, the first recording data for the first scanning direction and the second recording data for the second scanning direction, are generated. In addition, depending on the arrangement of the input image data, the second scanning direction, which is the opposite scanning direction, may not necessarily be optimal for the next carriage scan after the first scanning direction. The first printing area is recorded in the first scanning direction, and the carriage is stopped at the position where recording is completed. If there is only recording data in the first scanning direction from the carriage stop position in the second printing area adjacent to the first printing area, the scanning time is shortest if the next scan is also performed in the first scanning direction. In such a case, if the generation of recording data is performed after the scanning direction of each printing area is determined, processing time is required before the carriage scan starts, which leads to a deterioration in throughput.

[0011] The present invention provides a technology for suppressing degradation of image quality and throughput while achieving high-quality printing, even in cases where satellites accompanying main droplets of ink ejected in accordance with the scanning direction fly over a certain flight distance. [Means for solving the problem]

[0012] One aspect of the present invention is an image processing device comprising: an acquisition means for acquiring an input image including a target object; and a generation means for generating recording data indicating whether or not ink droplets are applied from a recording means based on the input image, wherein the recording means has a first recording element array and a second recording element array in which recording elements for applying ink droplets are arranged, and scans back and forth in a first direction and a second direction opposite to the first direction, wherein a ratio of pixels recorded by one or more recording elements included in the first recording element array among a plurality of pixels included in a first edge region of the target object is smaller than a ratio of pixels recorded by one or more recording elements included in the second recording element array, the first edge region is a region adjacent to the boundary where the object changes to a margin region of the recording medium when viewed in the first direction, and a ratio of pixels recorded by one or more recording elements included in the second recording element array among a plurality of pixels included in a second edge region of the target object is smaller than a ratio of pixels recorded by one or more recording elements included in the first recording element array, and the second edge region is a region adjacent to the boundary where the object changes to a margin region of the recording medium when viewed in the second direction. Effect of the Invention

[0013] According to the configuration of the present invention, even in cases where satellites accompanying main droplets of ink ejected in accordance with the scanning direction fly over a certain flight distance, it is possible to achieve high-quality printing while suppressing deterioration in image quality and throughput. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a diagram showing the configuration of a recording apparatus. [Diagram 2] FIG. 1 is a diagram showing a configuration including an image processing device. [Diagram 3] 4 is a flowchart showing a process of an image processing unit. [Figure 4] FIG. 4 is a diagram for explaining edge pattern detection. [Diagram 5] FIG. 1 is a diagram for explaining pattern matching. [Figure 6]4 is a flowchart showing a process of an image processing unit. [Figure 7] 4 is a flowchart showing a process of an image processing unit. [Figure 8] FIG. 11 is a diagram for explaining an index expansion process. [Figure 9] FIG. 2 is a diagram showing the configuration of a recording head. [Figure 10] 4 is a flowchart showing a process of an image processing unit. [Figure 11] 6A and 6B are diagrams for explaining an example of flight characteristics of main droplets and satellites of ink ejected from nozzles arranged in a first nozzle row. [Figure 12] FIG. 15 is a schematic diagram showing how a main droplet 1502, a satellite 1503, and a satellite 1504 land on a recording medium according to the scanning direction of the carriage. [Figure 13] FIG. 15 is a schematic diagram showing how a main droplet 1506, a satellite 1507, and a satellite 1508 land on a recording medium according to the scanning direction of the carriage. [Figure 14A] FIG. 4 is a diagram showing a recording head H and the quantization result of an input image. [Figure 14B] 1 is a diagram showing which nozzles arranged in a recording head H are responsible for which pixel positions. [Figure 14C] 6A and 6B are diagrams showing the results of edge processing detected by edge detection processing. [Figure 14D] 6A and 6B are diagrams relating to a process of thinning out print data arranged in a first edge region and a second edge region. [Figure 15] 13A to 13C are diagrams showing a print result when the character "a" is recorded based on recording data to which edge processing has not been applied, and a print result when the character "a" is recorded based on recording data generated by the first embodiment. [Figure 16] 13A and 13B are diagrams showing an example of a result of printing on a recording medium by repeating a plurality of recording scans by a carriage and conveyance of the recording medium based on recording data that has not been subjected to edge processing. [Figure 17] 13A and 13B are diagrams showing an example of a result printed on a recording medium by repeating a plurality of recording scans by a carriage and conveyance of the recording medium based on recording data that has been subjected to edge processing. [Figure 18] FIG. 2 is a diagram showing the configuration of a recording head. [Figure 19A] FIG. 4 is a diagram showing a recording head H and the quantization result of an input image. [Figure 19B] 1 is a diagram showing which nozzles arranged in a recording head H are responsible for which pixel positions. [Figure 19C] 6A and 6B are diagrams showing the results of edge processing detected by edge detection processing. [Figure 19D] 6A and 6B are diagrams relating to a process of thinning out print data arranged in a first edge region and a second edge region. [Figure 20] FIG. 7 is a diagram showing a modification of FIG. 6. [Figure 21] 6A and 6B are diagrams showing examples of dot arrangement patterns used in the index development process. [Figure 22] 6A and 6B are diagrams showing how nozzles used to print each pixel are determined; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0016] [First embodiment] <Structure of the recording device> The structure of the recording device in this embodiment will be described below with reference to FIG. 1. FIG. 1 is a perspective view showing an outline of a recording unit in a recording device 2 (hereinafter also simply referred to as a recording device). A recording medium P (hereinafter also simply referred to as a recording medium) fed to the recording unit is conveyed in the -Y direction (sub-scanning direction) by a nip between a conveying roller 101 arranged on a conveying path and a pinch roller 102 driven by the conveying roller 101 as the conveying roller 101 rotates. A platen 103 is provided at a recording position facing a surface (nozzle surface) on which nozzles are formed of a recording head H of an inkjet recording method, and supports the back surface of the recording medium P from below to maintain a constant distance between the front surface of the recording medium P and the nozzle surface of the recording head H. The recording medium P in the area where recording has been performed on the platen 103 is conveyed in the -Y direction as the discharge roller 105 rotates while being nipped by a discharge roller 105 and a spur 106 driven by the discharge roller 105, and is discharged to a paper discharge tray 107.

[0017] The print head H is detachably mounted on the carriage 108 with its nozzle surface facing the platen 103 or the print medium. The carriage 108 is reciprocated in the X direction, which is the main scanning direction, along two guide rails 109 and 110 by the driving force of a carriage motor (not shown), and during the movement, the print head H executes a discharge operation according to a discharge signal. The ±X direction in which the carriage 108 moves is a direction perpendicular (intersecting) to the -Y direction in which the print medium is transported, and is called the main scanning direction. In contrast, the -Y direction in which the print medium is transported is called the sub-scanning direction. An image is formed stepwise on the print medium P by alternately repeating the main scanning (movement accompanied by discharge) of the carriage 108 and print head H and the transport of the print medium (sub-scanning). The above is the content of the structure of the print device in this embodiment.

[0018] <Recording head structure> The structure of the print head in this embodiment will be described below with reference to FIG. 9. FIGS. 9(a) to 9(c) are schematic diagrams of the print head H used in this embodiment as viewed from above the printing apparatus. The lower side of the figure is the side from which the print medium is discharged in the printing apparatus. The print head H has print chips 1105 and 1106, each of which receives a print signal from the printing apparatus body via a contact pad (not shown), and is supplied with power required to drive the print head. As shown in FIG. 9(a), the print chip 1105 is provided with a nozzle row 1101 (hereinafter also referred to as a black nozzle row) in which a plurality of nozzles for ejecting black ink are arranged in the Y direction. Similarly, the print chip 1106 is provided with a nozzle row 1102 for ejecting cyan ink, a nozzle row 1103 for ejecting magenta ink, and a nozzle row 1104 for ejecting yellow ink.

[0019] FIG. 9(b) is an enlarged view of the nozzle row 1101 of the recording chip 1105. FIG. 9(c) is an enlarged view of one of the three nozzle rows, i.e., the nozzle rows 1102, 1103, and 1104, i.e., the nozzle rows for cyan, magenta, and yellow. This enlarged view is common to all color inks. On both sides of the ink liquid chambers 1107 and 1110, nozzles 1108 and 1111 that eject ink are arranged. Directly below (on the +Z direction side) each nozzle, heaters 1109 and 1112 are arranged as recording elements for ejection. The heaters 1109 and 1112 are so-called electrothermal conversion type recording elements, which generate heat when a voltage is applied to them, generating bubbles and ejecting ink droplets from each nozzle. The nozzle 1108 has 832 nozzles, and the nozzle 1111 has 768 nozzles.

[0020] Nozzle 1108 ejects black ink. Nozzle array 1101 includes a first nozzle array and a second nozzle array in which nozzles 1108 are arranged in the Y direction at a pitch of 600 dpi. Each nozzle of the first nozzle array is shifted in the -Y direction by half a pitch, i.e., 1200 dpi, from each nozzle of the second nozzle array. By performing a print scan using nozzle array 1101 configured in this way, it is possible to print on the print medium at a print density of 1200 dpi. Nozzle array 1102, nozzle array 1103, and nozzle array 1104 have the same configuration as nozzle array 1101.

[0021] The print head H of the present embodiment has a configuration including a print chip having a black nozzle row, and a print chip having a cyan nozzle row, a magenta nozzle row, and a yellow nozzle row, but is not limited to this configuration. Specifically, the black nozzle row, the cyan nozzle row, the magenta nozzle row, and the yellow nozzle row may all be mounted on one chip. Alternatively, a print head mounting a print chip having a black nozzle row and a print head mounting a print chip having a cyan nozzle row, a magenta nozzle row, and a yellow nozzle row may be separate. Alternatively, the black nozzle row, the cyan nozzle row, the magenta nozzle row, and the yellow nozzle row may each be mounted on a separate print head. In addition, the print head H of the present embodiment is a so-called bubble jet type that ejects ink by applying a voltage to a heater to generate heat, but is not limited to this configuration. Specifically, the print head may be configured to eject ink using an electrostatic actuator or a piezoelectric element. The above is the content of the structure of the print head in the present embodiment.

[0022] FIG. 2(a) is a diagram showing an example of the configuration of a printing system including an image forming apparatus 10 equipped with a recording device 2. FIG. 2(a) shows a cloud print system in which a terminal apparatus 11, a cloud print server 12, and an image forming apparatus 10 are connected via a network 13 as an example of a printing system. The cloud print server 12 is a server apparatus that provides a cloud print service. That is, in the configuration of FIG. 2(a), the image forming apparatus 10 is a cloud print-compatible printer. The network 13 is a wired network, a wireless network, or a network including both. The network 13 may be, for example, the Internet, a WAN, or a VPN environment. However, the printing system is not limited to the cloud print system. For example, the network 13 may be configured as an in-house LAN, or the terminal apparatus 11 and the image forming apparatus 10 may be configured to be directly connected without going through the network 13. FIG. 2(a) shows one each of the terminal apparatus 11 and the image forming apparatus 10, but there may be a plurality of the terminal apparatus 11 and the image forming apparatus 10. The cloud print server 12 may also be a server system configured of a plurality of information processing apparatuses. Furthermore, the printing system may be a cloud print system in which a plurality of cloud print services cooperate with each other.

[0023] The terminal device 11 is an information processing device such as a PC, tablet, or smartphone, and has a cloud printer driver for the cloud print service installed. A user can run any application software on the terminal device 11. For example, a print job is generated via the cloud printer driver based on image data generated on a print application. The print job is transmitted to an image forming device 10 registered in the cloud print service via a cloud print server 12. The image forming device 10 is a device that prints on a recording medium such as paper, and prints an image on the recording medium based on a received print job.

[0024] <Control system configuration> The configuration of the control system in this embodiment will be described below with reference to FIG. 2(b). FIG. 2(b) is a schematic diagram of the image processing device 100. In this embodiment, the image processing device 100 will be described as being included in the image forming device 10. However, the image processing device 100 may be configured as a device connected to the image forming device 10 including the printer 2 and the scanner 202. For example, the image processing device 100 may be configured inside the host computer 201. In that case, the image processing device 100 may not include the printhead control unit 213 and the scanner IF control unit 205.

[0025] The host computer 201 is an information processing device that creates a print job including input image data and recording condition information required for recording, and corresponds to, for example, the terminal device 11 in Fig. 2(a). Note that the recording condition information is information such as the type and size of recording paper, and recording quality.

[0026] The scanner 202 is a scanner device connected to the image processing device 100, and optically reads an original placed on a scanner table, generates analog data, and converts the data into digital data via an AD converter. Scanning by the scanner 202 is executed by sending a scan job from the host computer 201 to the image processing device 100, but is not limited to this. It may also be replaced by a dedicated UI device connected to the image processing device 100 or the scanner 202.

[0027] The ROM 206 is a readable memory that stores a program for controlling the image processing device 100. The CPU 203 controls the image processing device 100 by executing the program stored in the ROM 206. The host IF control unit 204 communicates with the host computer 201, receives print jobs, and stores them in the RAM 207. The RAM 207 is a readable and writable memory that is used as an execution area for programs and a storage area for data.

[0028] The image processing unit 208 generates nozzle data broken down into printable nozzle units from the input image data stored in the RAM 207 in accordance with the printing conditions included in the print job. The generated nozzle data is stored in the RAM 207. The image processing unit 208 is internally configured to include a decoder unit 209, a scan image correction unit 216, an image analysis unit 210, a color separation quantization unit 211, and a nozzle separation processing unit 212.

[0029] The printhead control unit 213 generates print data based on the nozzle data stored in the RAM 207, and controls the printhead H in the printer 2. The shared bus 215 is connected to each of the processing units, the CPU 203, the host IF control unit 204, the scanner IF control unit 205, the ROM 206, the RAM 207, and the image processing unit 208. The connected units can communicate with each other via the shared bus 215. The above is the configuration of the control system in this embodiment.

[0030] <Overall flow> The flow of edge processing according to this embodiment will be described below. Fig. 3(a) is a flow diagram showing the processing performed by the image processing unit 208 in this embodiment. In this embodiment, the input image data can be converted into nozzle data by the processing in Fig. 3(a).

[0031] In step S301, the image processing unit 208 acquires input image data from the RAM 207. In step S302, the decoder unit 209 performs a decoding process on the acquired input image data. There are various storage formats for the input image data, and a compression format such as JPEG is generally used to reduce the amount of communication between the host computer 201 and the image processing device 100. When the storage format is JPEG, the decoder unit 209 decodes the input image data in JPEG and converts it into image data (bitmap image) in a bitmap format (an information format in which an image is recorded as a continuous value of pixel values). When the host computer 201 communicates with the image processing device 100 via a dedicated driver or the like, a dedicated storage format may be used. When a dedicated storage format that is convenient for both the driver and the image processing device 100 is available, the decoder unit 209 can convert to the dedicated storage format. For example, it is also possible to apply a storage format with different compression rates between an area where information needs to be stored with fine accuracy and an area where it is not, according to the characteristics of the inkjet recording device. If emphasis is placed on image quality rather than on reducing the amount of communication, the input image data may be in bitmap format, in which case the decoder unit 209 may simply output the bitmap format as the conversion result.

[0032] In step S303, the image analysis unit 210 analyzes the bitmap image that is the decoded result. In this embodiment, the image is analyzed to estimate, based on the characteristics within the image, whether the target pixel is an edge of a pixel formed with paper white or a different ink from the target pixel. Also, it is estimated whether the target pixel is at the edge of an object (target object) formed by a group of pixels, in the top, bottom, left, or right direction.

[0033] 3(b) shows an internal processing flow for the image analysis processing performed in step S303. In step S401, the image analysis unit 210 converts pixel values ​​of the bitmap image, which is the decoded result, into luminance values. For example, when pixel values ​​of the bitmap image are pixel values ​​of three channels of RGB (RGB values), the pixel values ​​are converted into pixel values ​​of one channel of luminance Y (luminance value). Note that, when image data transmitted from a user by an application is already expressed in luminance, the processing of step S401 does not need to be performed.

[0034] In step S402, the image analysis unit 210 converts the luminance Y data into binary data for edge detection. In the present embodiment, as an example, the luminance Y data is converted into binary data (Bin) according to the following conditional formula (1) using threshold data Th that is provided in advance in accordance with the recording mode of the recording device. The following conditional formula, which is the binary data generation formula, is an example, and the design of the inequality condition and the form of the formula are not limited to this.

[0035] IF Y > Th : Bin = 0 else : Bin = 1 (1) In this embodiment, image analysis is performed using an index called luminance. In an inkjet recording device, the gradation using black ink in color separation is limited. This is because the black ink has a large change in paper surface density for each drop with respect to the white paper, and the use of black ink in large quantities from a light gradation is likely to cause a deterioration in image quality in terms of graininess. For this reason, it is easier to determine the ink generation position of black ink based on the luminance information of the input image compared to other color inks. By setting the above threshold data Th to an appropriate value, it is possible to set a luminance value corresponding to the gradation at which a predetermined amount or more of black ink after ink separation begins to be applied for the luminance information. In this embodiment, it is possible to control the number and arrangement of black ink dots, and the number and arrangement of dots of other color inks adjacent to black ink, and the use of luminance values ​​is in line with this control. However, this embodiment is not limited to this. For example, color separation may be performed in advance for this analysis process to accurately grasp the pixels where black ink occurs as a predetermined color component. If color separation is performed in advance, it is possible to grasp the pixels where not only black ink but also cyan, magenta, and yellow ink occurs and the ejection amount, making it possible to perform a more detailed analysis. There may be cases where the input image data contains information that is useful for analysis, such as the input image data being in CMYK format rather than RGB format. If the ejection amounts of cyan, magenta, and yellow inks are known, it may be possible to make a judgment such as assuming that a small ejection amount is the same as paper white and analyzing the black ink occurring in an area on the paper surface that is equivalent to paper white. In this embodiment, such judgments are expressed by threshold data Th. The threshold data Th may be updated successively based on the degree of wear of each nozzle of the nozzle rows 1101 to 1104 of the print head in the printing apparatus.

[0036] In step S403, the image analysis unit 210 performs edge pattern detection using the binary data. Examples of pattern information for edge pattern detection are shown in Figs. 4(a) and 4(b). There are two types of pattern information: "information for generating pattern matching data" and "information for generating edge pattern detection result". The information for generating pattern matching data is information for performing a bit AND process on each pixel of the rectangular area of ​​the binary data obtained in step S402. The pattern matching data obtained as a result of the bit AND process is in a form in which only information necessary for detecting an edge pattern in the rectangular area is extracted. The information for generating edge pattern detection result is information for performing a pattern matching process on the pattern matching data. If a perfect match is found as a result of the pattern matching process, the rectangular area is determined to be a predetermined edge pattern. The determination result is linked to the center pixel in the rectangular area.

[0037] FIG. 4(a) shows pattern information for determining that the target pixel is "the left and right ends of a 1-dot vertical line." The pattern matching data generation information is set to a value so that edge pattern detection is performed on 3×3 pixels including the target pixel. A pixel assigned with "0" in the pattern matching data generation information is considered to be a pixel that is not considered in pattern matching, regardless of how the binary data is formed. Next, the edge pattern detection result generation information corresponds to the above-mentioned predetermined edge pattern, and in this example, it is a pattern in which only the central row and vertical three pixels in the 3×3 pixels are set to 1. This information is equivalent to determining whether the central row and vertical three pixels are low-luminance and the other six pixels are high-luminance. If the pattern matching data completely matches this pattern, it can be seen that at least the left and right sides have high-luminance characteristics = paper white or low-density color ink, and the target pixel and the upper and lower sides have low-luminance characteristics = black ink.

[0038] Figure 4(b) shows pattern information for determining that the target pixel is not only "the left or right end of a 1dot vertical line" but also "part of a 1dot1space." "1dot1space" refers to a pattern in which multiple 1dot vertical lines are arranged at 1dot intervals. By expanding the range of the pattern matching data generation information to 7x3 pixels, it is possible to include information about the surroundings of the 1dot line to which the target pixel belongs in the determination.

[0039] Figure 4(c) shows the results of sequentially performing pattern matching on binary data using Figures 4(a) and (b). When the pattern matching data generation information and edge pattern detection result generation information in Figure 4(a) are applied to the target binary data, the judgment result is "match." When the pattern matching data generation information and edge pattern detection result generation information in Figure 4(b) are applied, the judgment result is "mismatch." Based on the detection results of the two patterns, it can be seen that the target binary data "is the left or right end of a 1dot vertical line" and "is not part of a 1dot1space."

[0040] Based on the above method, it is possible to detect various edge patterns. In this embodiment, the target of pattern matching is 7×7 pixels, but this is only one example. For example, if it is sufficient to be able to detect the patterns in FIG. 4(a) and (b), the target of pattern matching is 7×3 pixels. On the other hand, if it is desired to individually detect line shapes of 4 dots or more, 7×7 pixels is not sufficient, and a wider area may be set as the target. By expanding the target, more work memory for holding the binary data to be compared and work memory for holding the pattern matching information are required. The work memory corresponds to the RAM 207. When the image analysis unit 210 is a dedicated circuit, if it is desired to process multiple pixels with parallel clks for pattern matching, the number of processing registers and processing circuits will also increase. In addition, since the pattern matching information needs to be held in the ROM 206 of the image processing device 100 in advance, the capacity of the ROM 206 is also required. When checking edge patterns in detail and in a variety of ways, a lot of pattern matching information must be stored, so the design must take into account the memory capacity and the increase in analysis time due to the increase in the number of comparisons. The determination of "0" = "not considered in pattern matching" in the pattern matching data generation information contributes to reducing memory capacity and the number of comparisons. As another configuration for reducing memory capacity, as shown in Figure 5, pattern matching of different variations can be performed by processing such as rotation and phase shift. In the upper part of Figure 5, the pattern matching information shown in Figure 4(a) is rotated 90 degrees, and the processed pattern information can be used to determine that "it is the upper and lower ends of a 1-dot horizontal line." In the lower part of Figure 5, the pattern information shown in Figure 4(a) is shifted horizontally by one pixel, and the processed pattern matching information can be used to determine that "it is an adjacent pixel of a 1-dot vertical line." In Figure 5, the pattern matching information is processed to increase the variation, but the binary data side can also be processed to increase the variation.

[0041] As shown in Fig. 4(c), it is also effective to narrow down the judgment results by sequentially applying multiple pattern matching information, or to obtain information that could not be obtained from individual pattern matching information. For example, in Fig. 4(c), when the pattern in Fig. 4(a) is "matched", it is not necessary to perform the judgment on the 2-dot line or more that was prepared in advance. Also, by applying only the pattern matching information that judges more detailed information on the 1-dot line, as shown in Fig. 4(b), it is possible to reduce the number of comparisons. Also, by applying Fig. 4(a) and (b), it is possible to know that the target binary data is "the left and right ends of a 1-dot vertical line" and "not part of a 1-dot 1-space". By deriving this information from the results of both Fig. 4(a) and (b) rather than preparing individual pattern matching information that can be obtained, it is effective in reducing memory capacity.

[0042] As described above, this embodiment can determine whether a pixel requires special processing such as thinning out dots or changing the arrangement of dots. This processing is just one example, and an example in which there are more restrictions on the memory and speed of the image processing device 100 will be described later in another embodiment.

[0043] The result of the image analysis process in step S303 is output in an information format suitable for processing in the following steps. For example, the result of the determination can be expressed as a 3-bit multi-value such as non-detection (not applicable to any detection pattern) = 0, upper end detection = 1, lower end detection = 2, left end detection = 3, right end detection = 4, adjacent to some end = 5. Alternatively, each bit within 5 bits can be expressed as non-detection = 00000, upper end detection = 00001, lower end detection = 00010, left end detection = 00100, right end detection = 01000, adjacent to some end = 10000. The former has a small amount of data and can be transmitted to the next process. The latter has the advantage of being able to use bit processing in the next process, thereby reducing the processing load. Here, it is described that five pieces of information are transmitted to the following steps, but as explained in the explanation of step S303 that "pattern matching information can be expressed in various ways," more information than the control information required in the following processing steps may be detected and transmitted.

[0044] 6 and 7(a) show an example of the internal processing flow of the color separation quantization process performed in step S304 and the nozzle separation process performed in step S305, respectively. As a premise for the following explanation, it is assumed that the bitmap image resulting from the decoding in step S302 has 8-bit 256-level luminance values ​​for each of R (red), G (green) and B (blue) arranged at 600 dpi in each pixel. In addition, in the end information detected in step S303, the upper end (first end) is defined as the pixel on the side where Bin changes from 1 to 0 and Bin=1 in the -Y direction, the lower end (second end) is defined as the pixel on the +Y direction, the right end (fourth end) is defined as the pixel on the +X direction, and the left end (third end) is defined as the pixel on the -X direction. The nozzles of each color of the print head H are arranged at 1200 dpi in the Y direction per color, so that each pixel is printed using the first nozzle row and the second nozzle row that are consecutive with each other. Here, the nozzles located on the upper end side of each pixel are defined as upstream nozzles, and the nozzles located on the lower end side of each pixel are defined as downstream nozzles. In this embodiment, the upstream nozzles correspond to the first nozzles, and the downstream nozzles correspond to the second nozzles. That is, in this embodiment, the recording resolution is twice as high in the Y direction as the resolution of the image data for edge pattern detection.

[0045] In the color correction process of step S801, the color separation and quantization unit 211 converts the RGB data of each pixel into R'G'B' data expressed in a color space specific to the recording device. A specific conversion method may be, for example, by referring to a lookup table stored in advance in memory.

[0046] In step S802, the color separation and quantization unit 211 performs color separation processing on the R'G'B' data. Specifically, by referring to a lookup table stored in advance in memory, the luminance value R'G'B' of each pixel is converted into 8-bit 256-level density value CMYK corresponding to the ink color used by the recording device. Furthermore, the color separation and quantization unit 211 duplicates the density value data of one or more colors of CMYK to generate a total of two identical data. For simplicity, the following will show an example of generating black data K1 and K2. Note that K1 and K2 are applied to the first nozzle row and the second nozzle row of the nozzle row 1101, respectively, by processing described later.

[0047] In steps S803 to 805, the color separation and quantization unit 211 performs separate gradation correction processes based on whether the pixel to be processed is the second end or not, using the density value K1 and the result of the determination in step S303. Furthermore, in steps S806 to 808, the color separation and quantization unit 211 performs separate gradation correction processes based on whether the pixel to be processed is the first end or not, using the density value K2 and the result of the determination in step S303. The gradation correction process is a correction for making the input density value and the optical density expressed by the recording medium P have a linear relationship. This correction process converts the 8-bit 256-level density values ​​K1 and K2 into density values ​​K1'K2' also of 8 bits and 256 levels. If the pixel is detected to be the second end in step S303, the density value K1 is converted to K1'=0 in step S805, and if not, it is converted to K1' in the first gradation correction process in step S804. On the other hand, if the pixel is detected to be the first end in step S303, the density value K2 is converted to K2'=0 in step S808, and if not, it is converted to K2' in the first gradation correction process in step S807. Figures 7(b) and (c) are diagrams showing examples of settings for the first gradation correction process, where In corresponds to the density values ​​K1 and K2, and Out corresponds to the density values ​​K1' and K2'. For simplicity, this explanation shows an example in which In and Out have a linear relationship.

[0048] In step S809, the color separation and quantization unit 211 performs a predetermined quantization process on the density value K1' to convert it into 4-bit 3-value quantized data (quantized value) of "0000", "0001", and "0010". In this example, it is expressed as three values ​​of low density, medium density, and high density. Furthermore, in steps S810 to 812, the color separation and quantization unit 211 uses the result of the determination in step S303 to set a value to the most significant bit based on whether the pixel to be processed is the first end or not, and outputs 4-bit quantized data K1''. Specifically, if the pixel is detected to be the first end, the most significant bit is set to 1 in step S812, and if not, the most significant bit is set to 0 in step S811. Similarly, in step S813, the color separation and quantization unit 211 performs a predetermined quantization process on the density value K2' to convert it into 4-bit 3-value quantized data of "0000", "0001", and "0010". In this example, it is expressed as three values: low density, medium density, and high density. Furthermore, in steps S814 to S816, the decomposition quantization unit 211 uses the result of the determination in step S303 to set a value to the most significant bit based on whether the pixel to be processed is at the second end or not, and outputs 4-bit quantized data K2". Specifically, if it is detected as the second end, the most significant bit is set to 1 in step S816, and if not, the most significant bit is set to 0 in step S815.

[0049] In step S305, the nozzle resolution processing unit 212 performs index expansion processing on the quantized data K1'' and K2'' output in step S304. In the index expansion processing of this embodiment, a prepared index pattern is used to convert the 600 x 600 dpi quantized data K1'' and K2'' into 600 dpi x 600 dpi binary nozzle data K1p, K2p. The quantized data K1'' is converted into nozzle data K1p in a first index expansion processing in step S817 of FIG. 7(a), and the quantized data K2'' is converted into nozzle data K2p in a second index expansion processing in step S818. In other words, an index pattern is a dot arrangement pattern for arranging dots in pixels.

[0050] 8(a) to 8(d) are diagrams showing examples of dot arrangement patterns and reference index patterns used in the index expansion process. The upper side of the diagram is the side to which the recording medium is discharged in the recording device. FIG. 8(a) is a diagram showing dot arrangement patterns in the first index expansion process. When quantized data K1'' of one pixel of 600 dpi x 600 dpi indicates "0000" or "1000", dots are not arranged in the corresponding pixel. When quantized data K1'' indicates "0001", pattern A in which dots are arranged and pattern B in which dots are not arranged are prepared. When quantized data K1'' indicates "0010", "1001", or "1010", dots are always arranged in the corresponding pixel. FIG. 8(b) is a diagram showing dot arrangement patterns in the second index expansion process. When quantized data K2'' of one pixel of 600 dpi x 600 dpi indicates "0001", pattern A in which dots are not arranged and pattern B in which dots are arranged are prepared. When the quantized data K2'' indicates "0000", "1000", "0010", "1001", or "1010", the process is the same as the first index expansion process. FIG. 8C is a diagram showing an example of a reference index pattern. In this embodiment, different index patterns are used in the first index expansion process in step S817 and the second index expansion process in step S818, but both are created based on the reference index pattern in FIG. 8C. In the reference index pattern, each square corresponds to a one-pixel area of ​​600 dpi x 600 dpi, and it is determined whether dots are arranged in pattern A or pattern B in each pixel. The nozzle resolution processing unit 212 generates nozzle data K1p of each pixel after the first index expansion process as data for the first nozzle row of the nozzle row 1101 corresponding to each pixel, and stores the data in the RAM 207. Furthermore, the nozzle resolution processing unit 212 generates nozzle data K2p for each pixel after the second index expansion processing as data for the second nozzle array of the nozzle array 1101 corresponding to each pixel, and stores this in the RAM 207.FIG. 8(d) shows binary data of 600 dpi in the X direction and 1200 dpi in the Y direction after index expansion processing in the case where the quantized data of each pixel is all uniformly "0001" (medium density), and the positional relationship between the data and the nozzles of the nozzle array 1101. As shown in the figure, of the data in the Y direction, dots are formed by the nozzles (first nozzles) in the first nozzle array for 0, 2, 4..., and by the nozzles (second nozzles) in the second nozzle array for 1, 3, 5.... As a result, printing or non-printing of each nozzle of the nozzle array 1101 is set for each pixel of the input image data of 600 dpi x 600 dpi, and printing or non-printing (with or without application of ink droplets) of 600 dpi x 1200 dpi is set. The data generated in this manner is called print data. The above is the content of the flow of edge processing according to this embodiment.

[0051] <Modifications of Color Separation and Quantization Unit and Nozzle Separation Processing Unit> The processing of the color separation and quantization unit 211 and the nozzle separation processing unit 212 in realizing this embodiment is not limited to the examples shown in Figs. 6 to 8. For example, the setting example of the index expansion processing shown in Figs. 8(a) and (b) is a so-called 1-bit index pattern in which the dot arrangement pattern and nozzle data are equivalent to the dot arrangement information, but is not limited to this example. For example, for a dot arrangement pattern of one pixel, a pixel in which a dot is not arranged may be expressed as "00", and a pixel in which a dot is arranged may be expressed as "01" if the most significant bit of the quantized data is "0", and "10" if the most significant bit of the quantized data is "1". Furthermore, the nozzle separation processing unit 212 may multiply the nozzle data K1p, K2p generated based on the dot arrangement pattern by a mask pattern to generate nozzle data K1p', K2p' equivalent to the dot arrangement condition. Here, the mask pattern is a 2-bit representation of one pixel stored in the ROM 206 or the RAM 207. For example, when the nozzle data K1p is "00", any mask pattern can be set as K1p'=0 to obtain the same dot arrangement condition as in this embodiment. Furthermore, when the nozzle data K1p is "01", the mask pattern is set as "01" or "11", and when the nozzle data K1p is "10", the mask pattern is set as "10" or "11" and K1p'=1, and a predetermined mask pattern is applied to obtain the same dot arrangement condition as in this embodiment. The nozzle data K2p is also the same as K1p. Also, in FIG. 6, an example is shown in which the density value K1 referred to in the first nozzle row and the density value K2 referred to in the second nozzle row are processed, but the processing shown in FIG. 20 to FIG. 21 may be used.

[0052] 20(a) and (b) are diagrams showing a modified example of FIG. 6. Step S2401 is similar to step S801, and therefore description thereof will be omitted. In step S2402, the color separation and quantization unit 211 performs color separation processing on the R'G'B' data and converts it into density values ​​CMYK. The method of conversion is similar to that of step S802. However, unlike step S802, no duplication processing of density value data is performed. For simplicity, an example of processing black data K will be shown below.

[0053] In step S2403, the color separation and quantization unit 211 performs tone correction processing on the density value K to convert it into a density value K'. The tone correction processing method is the same as in step S804 or step S807, and therefore description thereof will be omitted.

[0054] In step S2404, the color separation and quantization unit 211 performs a predetermined quantization process on the density value K' to convert it into 4-bit 3-value quantized data of "0000", "0001", and "0010". Furthermore, in steps S2405 to S2409, the color separation and quantization unit 211 uses the result determined in step S303, sets a value to the most significant 2 bits based on the end information of the pixel to be processed, and outputs 4-bit quantized data K''. If the pixel is detected to be the first end, the most significant 2 bits = 01 in step S2409, and if the pixel is detected to be the second end rather than the first end, the most significant 2 bits = 10 in step S2408. If neither the first end nor the second end is detected, the most significant 2 bits = 00 in step S2407.

[0055] In step S2410, the nozzle resolution processing unit 212 performs index expansion processing on the quantized data K'' output in step S304. In the index expansion processing in this example, a prepared index pattern is used to convert the 600 x 600 dpi quantized data K'' into 600 dpi x 600 dpi binary nozzle data K1p, K2p.

[0056] FIG. 21 is a diagram showing an example of a dot arrangement pattern used in the index expansion process. The dot arrangement pattern in FIG. 21 is one in which 600 dpi x 1200 dpi arrangement information is linked above and below. When the quantized data K'' indicates "0000", "0100", or "1000", dots are not arranged above or below the corresponding pixel. When the quantized data K'' indicates "0001", pattern A for arranging dots on the upper side and pattern B for arranging dots on the lower side are prepared. When the quantized data K'' indicates "0010", dots are always arranged above and below the corresponding pixel. When the quantized data K'' indicates "0101" or "0110", dots are always arranged above the corresponding pixel, and dots are never arranged below. When the quantized data K'' indicates "1001" or "1010", dots are always arranged below the corresponding pixel, and dots are never arranged above. The reference index pattern is the same as that in FIG. 8(c). Then, the nozzle resolution processing unit 212 generates the upper data of the top and bottom arrangement information of each pixel as nozzle data K1p as data for the first nozzle row of the nozzle row 1101 corresponding to each pixel, and stores this in RAM 207. Furthermore, the nozzle resolution processing unit 212 generates the lower data of the composite nozzle data Kp of each pixel as nozzle data K2p as data for the second nozzle row of the nozzle row 1101 corresponding to each pixel, and stores this in RAM 207.

[0057] According to the above flow, the data printed by each nozzle becomes the same as the flow shown in Fig. 6 to Fig. 8, and the same effect can be obtained. Specifically, for example, in the case of "0110" indicating the upper end, a dot is never placed below the corresponding pixel, and in the case of "1010" indicating the lower end, a dot is never placed above the corresponding pixel. The above is the content related to the modified example of the color separation quantization unit and nozzle separation processing unit according to this embodiment.

[0058] <Processing when nozzles are shifted> In this embodiment, an example is shown in which the upstream nozzle of each pixel is the first nozzle and the downstream nozzle is the second nozzle, but this is merely an example. For example, in order to correct a physical positional deviation in the Y direction that may occur between the black nozzle row 1101 and the nozzle rows 1102 to 1104 of other colors, the black nozzle may be shifted in the Y direction by 1200 dpi x odd number with respect to the input image and printed. In this case, the Ev and Od nozzles to be used may be swapped (0th, 2nd, 4th, etc. in the Y direction are Ev nozzles, and 1st, 3rd, 5th, etc. are Od nozzles). In step S305, the nozzle resolution processing unit 212 generates the nozzle data K1p as data for the second nozzle of the nozzle row 1101, and generates K2p as data for the first nozzle of the nozzle row 1101, thereby obtaining the same effect. The above is the content related to the process when shifting the nozzle to be used according to this embodiment.

[0059] <Processing other than the black nozzle row> In this embodiment, the processing from step S803 onwards has been described for black data only, but in step S802, density value data other than black data, i.e. cyan, magenta and yellow data, are also output. These may be processed in the same way as black data. Alternatively, a different process from that for black data may be used, as shown below.

[0060] 10 shows an example of the internal processing flow of the color separation quantization processing performed in step S304 for cyan, magenta, and yellow, and the nozzle separation processing performed in step S305. Steps S1201 and S1202 are the same as steps S801 and S802, respectively. Also, steps S1203 and S1204 are the same as steps S804 and S809, respectively. Therefore, the description thereof will be omitted.

[0061] In step S1205, the color separation and quantization unit 211 uses the result determined in step S303 and outputs 4-bit quantized data C'', M'', Y'' based on which end the pixel to be processed is adjacent to. The end here is, for example, the first end or the second end. Specifically, if it is detected that the pixel is adjacent to which end, then in step S1207 the most significant bit of the quantized data is set to 1, and if not, in step S1206 the most significant bit of the quantized data is set to 0.

[0062] In step S1208, the nozzle resolution processing unit 212 performs index expansion processing on each of the quantized data C'', M'', and Y'' output in step S304. In the index expansion processing in this example, a prepared index pattern is used to convert the 600 dpi x 600 dpi quantized data C'', M'', and Y'' into 600 dpi x 600 dpi binary nozzle data C1p, C2p, M1p, M2p, Y1p, and Y2p.

[0063] 10(c) and (d) are diagrams showing examples of dot arrangement patterns used in index expansion processing, where FIG. 10(c) is an arrangement pattern for Y'', and FIG. 10(d) is an arrangement pattern for C'' and M''. The dot arrangement patterns in FIG. 10(c) and (d) are such that 600 dpi x 1200 dpi arrangement information is linked vertically. When quantized data C'', M'', and Y'' respectively indicate "0000" and "1000", dots of the corresponding color are not arranged on either the top or bottom of the corresponding pixel. When quantized data C'', M'', and Y'' respectively indicate "0001", pattern A is prepared in which dots of the corresponding color are arranged on the top, and pattern B is prepared in which dots of the corresponding color are arranged on the bottom. When quantized data C'', M'', and Y'' respectively indicate "0010", dots of the corresponding color are arranged on either the top or bottom of the corresponding pixel. For quantized data C'', M'', and Y'', dots of the corresponding color are arranged on either the top or bottom of the corresponding pixel even when "1010" is indicated. On the other hand, when the quantized data Y'' indicates "1010", a pattern A in which dots of the color are arranged on the upper side and a pattern B in which dots of the color are arranged on the lower side are prepared. The reference index pattern is the same as that in FIG. 8(c). Then, the nozzle resolution processing unit 212 generates the upper data of the upper and lower arrangement information of the cyan dots of each pixel as nozzle data C1p as data for the first nozzle of the cyan nozzle array 1102 corresponding to each pixel, and stores it in the RAM 207. Furthermore, the nozzle resolution processing unit 212 generates the lower data of the upper and lower arrangement information of the cyan dots of each pixel as nozzle data C2p as data for the second nozzle of the cyan nozzle array 1102 corresponding to each pixel, and stores it in the RAM 207. The same is true for magenta and yellow. As described above, for cyan and magenta, the dots are arranged in the same way regardless of whether the pixel is adjacent to any edge, so dot thinning is not performed. On the other hand, for yellow, if the pixel is adjacent to any edge, dot thinning is performed. Here, it has been explained that dots are thinned out when yellow is adjacent to any edge, but this is not limited to yellow, and thinning may also be performed on cyan and magenta dots when they are adjacent to any edge.The above is a description of the processing for the nozzle rows other than the black nozzle row. Note that this description is common to all the embodiments. <Flight characteristics of main droplets and satellites depending on scanning direction> FIG. 11 is a diagram for explaining an example of flight characteristics of main droplets and satellites of ink ejected from nozzles arranged in a first nozzle row mounted on a print head used in this embodiment.

[0064] 11(a) shows a cross-sectional view of a nozzle included in the first nozzle row, where ink is supplied from an ink tank that stores ink through a common ink flow path on the left side of the figure. Droplets of ink are ejected by the pressure of bubbles generated by heating a heating element 1501. At this time, if flow resistance is strong to the right side of the figure, asymmetry occurs in the ink flow path direction, causing the shape of the bubble and the meniscus when foaming and defoaming to become asymmetric, resulting in an ejection characteristic in which the tail bends to the side farther from the ink flow path on the left side.

[0065] Fig. 11(b) shows the flight characteristics of the main droplet and satellites of the ink droplets ejected from the nozzle described using Fig. 11(a). In Fig. 11(a), the tail bends in the opposite direction to the ink flow path on the left, so the centers of satellites 1503 and 1504 are shifted to the right in the figure relative to the center of the main droplet 1502.

[0066] 11(c) shows a cross-sectional view of a nozzle included in the second nozzle row, where ink is supplied from an ink tank that stores ink through a common ink flow path on the right. Ink droplets are ejected by the pressure of bubbles generated by heating the heating element 1505. At this time, if the flow resistance is strong to the left in the figure, asymmetry occurs in the ink flow path direction, which causes the shape of the bubble and the meniscus when foaming and defoaming to become asymmetric, resulting in an ejection characteristic in which the tail bends to the side farther from the ink flow path on the right.

[0067] Figure 11(d) shows the flight characteristics of the main droplet and satellite of the ink droplet ejected from the nozzle described using Figure 11(c). In Figure 11(c), the tail bends in the opposite direction to the ink flow path on the right side, so the centers of satellites 1507 and 1508 are shifted to the left side of the figure relative to the center of the main droplet 1506. The above is called the first ink droplet flight characteristic.

[0068] 11(e) shows a cross-sectional view of a nozzle included in the first nozzle row, where ink is supplied from an ink tank that stores ink through a common ink flow path on the left. Droplets of ink are ejected by the pressure of bubbles generated by heating the heating element 1501. At this time, if flow resistance is strong to the left in the figure, asymmetry occurs in the ink flow path direction, causing the shape of the bubble and the meniscus when foaming and defoaming to become asymmetric, resulting in an ejection characteristic in which the tail bends toward the ink flow path on the left.

[0069] Fig. 11(f) shows the flight characteristics of the main droplet and satellites of the ink droplets ejected from the nozzle described using Fig. 11(e). In Fig. 11(e), the tail bends toward the ink flow path on the left, so the centers of satellites 1503 and 1504 are shifted to the left side of the figure relative to the center of the main droplet 1502.

[0070] 11(g) shows a cross-sectional view of a nozzle included in the second nozzle row, where ink is supplied from an ink tank that stores ink through a common ink flow path on the right. Ink droplets are ejected by the pressure of bubbles generated by heating the heating element 1505. At this time, if the flow resistance to the right in the figure is strong, asymmetry occurs in the ink flow path direction, causing the shape of the bubble and the meniscus when foaming and defoaming to become asymmetric, resulting in an ejection characteristic in which the tail is bent toward the ink flow path on the right.

[0071] Figure 11(h) shows the flight characteristics of the main droplet and satellite of the ink droplet ejected from the nozzle described using Figure 11(g). In Figure 11(g), the tail bends toward the ink flow path on the right side, so the centers of satellites 1507 and 1508 are shifted to the right side in the figure relative to the center of the main droplet 1506. The above are defined as second ink droplet flight characteristics, which are flight characteristics different from the first ink droplet flight characteristics.

[0072] The above is a description of the flight characteristics of the main droplets and satellites depending on the scanning direction of the carriage. As in this example, the flight characteristics of the main droplets and satellites do not have to be contrasting depending on the scanning direction of the carriage, but it is sufficient that the flight distances of the main droplets and satellites are different between the first scanning direction and the second scanning direction, which is the scanning direction opposite to the first scanning direction. In addition, it is not limited to the difference in flight characteristics of the main droplets and satellites caused by the nozzle structure as described above. For example, it is also possible that the flight characteristics of the main droplets and satellites are different between the front nozzle row and the rear nozzle row in the traveling direction of the carriage due to the influence of the air flow generated by the carriage scanning and ink ejection (not shown). In this embodiment, a recording head having the above-mentioned first ink droplet flight characteristics will be described as an example.

[0073] Fig. 12 is a schematic diagram showing how a main droplet 1502, a satellite 1503, and a satellite 1504 land on a recording medium according to the carriage scanning direction when the main droplet and satellite are ejected from the nozzles of the first nozzle row group in the flight characteristics shown in Fig. 11(b). The horizontal arrows in the figure represent the force applied in the carriage scanning direction, and the downward arrows represent the force applied by ink ejection. The diagram shows the progress up to the landing of droplets in chronological order in the case of the first scanning direction in which the carriage moves to the right in the figure in the order of Fig. 12(a), (b), (c), and (d).

[0074] In FIG. 12(a), the center of satellite 1503 is further forward in the traveling direction than the center of main droplet 1502, and the center of satellite 1504 is further forward in the traveling direction than the center of satellite 1503. In FIG. 12(b), main droplet 1502 lands on the recording medium, while satellites 1503 and 1504 continue to fly. In FIG. 12(c), satellite 1503 lands in an area that does not overlap with the ink applied portion of main droplet 1502, and satellite 1504 continues to fly. In FIG. 12(d), satellite 1504 lands in an area that does not overlap with the ink applied portion of main droplet 1502 and satellite 1503. As a result, satellites 1503 and 1504 land at positions away from the landing position of main droplet 1502.

[0075] In the second scanning direction, the carriage moves leftward in the figure in the order of Figures 12(e), (f), (g), and (h), which show the progress up to landing in a chronological order. In Figure 12(e), the center of satellite 1503 is further back in the traveling direction than the center of main droplet 1502, and the center of satellite 1504 is further back in the traveling direction than the center of satellite 1503. In Figure 12(f), the main droplet 1502 lands on the recording medium, and satellites 1503 and 1504 continue to fly. In Figure 12(g), the satellite 1503 lands in an area overlapping the ink applied portion of the main droplet 1502, and satellite 1504 continues to fly. In Figure 12(h), the satellite 1504 lands in an area overlapping the ink applied portion of the main droplet 1502 or the satellite 1503. As a result, satellites 1503 and 1504 land at positions close to the landing position of the main droplet 1502 .

[0076] Figure 13 is a schematic diagram showing how a main droplet 1506, a satellite 1507, and a satellite 1508 land on a recording medium according to the carriage scanning direction when the main droplet and satellite ejection from the nozzles of the second nozzle array group have the flight characteristics shown in Figure 11(d). In the figure, the horizontal arrows indicate the force applied in the carriage scanning direction, and the downward arrows indicate the force applied by ink ejection. In the first scanning direction, the carriage moves to the right in the figure in the order of Figures 13(a), (b), (c), and (d), and the progress up to the landing is shown in chronological order.

[0077] In FIG. 13(a), the center of satellite 1507 is further back in the traveling direction than the center of main droplet 1506, and the center of satellite 1508 is further back in the traveling direction than the center of satellite 1507. In FIG. 13(b), main droplet 1506 lands on the recording medium, and satellites 1507 and 1508 continue to fly. In FIG. 13(c), satellite 1507 lands in an area overlapping an area applied with ink by main droplet 1506, and satellite 1508 continues to fly. In FIG. 13(d), satellite 1508 lands in an area overlapping an area applied with ink by main droplet 1506 or satellite 1507. As a result, satellites 1507 and 1508 land in close proximity to the landing position of main droplet 1506.

[0078] In the second scanning direction, the carriage moves leftward in the figure in the order of Figures 13(e), (f), (g), and (h), and the progress up to landing is shown in chronological order. In Figure 13(e), the center of satellite 1507 is further forward in the moving direction than the center of main droplet 1506, and the center of satellite 1508 is further forward in the moving direction than the center of satellite 1507. In Figure 13(f), the main droplet 1506 lands on the recording medium, and satellites 1507 and 1508 continue to fly. In Figure 13(g), the satellite 1507 lands in an area that does not overlap with the ink applied by the main droplet 1506, and the satellite 1508 continues to fly. In Figure 13(h), the satellite 1508 lands in an area that does not overlap with the ink applied by the main droplet 1506 and the satellite 1507. As a result, satellites 1507 and 1508 land at positions separated from the landing position of the main droplet 1506 .

[0079] The above is an explanation of the flight characteristics of the main droplets and satellites depending on the scanning direction of the carriage, and the landing positions of the main droplets and satellites on the recording medium. As described above, when the flight characteristics of the main droplets and satellites of the ink droplets ejected from each nozzle row group differ depending on the scanning direction of the carriage, the amount of satellites scattered around the edge area differs between the edge adjacent to the boundary between the object and the margin area of ​​the recording medium in the first scanning direction and the edge area adjacent to the boundary between the object and the margin area of ​​the recording medium in the second scanning direction. An example of edge area image processing that thins out the recording pixels in consideration of the flight characteristics described above will be shown. In this embodiment, the description will be given using a recording head with the nozzle row arrangement shown in FIG. 9.

[0080] 14A to 14D are diagrams for explaining the processing applied to each of the first edge region and the second edge region detected by the above-mentioned edge detection processing of this embodiment. Here, the scanning direction of the carriage is the X direction in the drawings. The first edge region is a region made up of edge pixels on the object side adjacent to the boundary where the object changes to the margin region when viewed in the +X direction. Similarly, the second edge region is a region made up of edge pixels on the object side adjacent to the boundary where the object changes to the margin region when viewed in the -X direction.

[0081] 14A is a diagram showing a print head H and "print data for a print resolution of 600 dpi in the X direction and 1200 dpi in the Y direction" which is the result of quantization of an input image. X0 to X19 in the diagram represent pixel positions corresponding to the carriage scanning direction, and Y0 to Y19 in the diagram represent pixel positions corresponding to the print medium transport direction. The downward direction in the diagram is the paper feed direction.

[0082] On the right side of the recording head H, first nozzles with even Seg numbers are arranged at 600 dpi intervals and are responsible for recording pixels at pixel positions Ye (e is an even number) among pixel positions Y0 to Y19. On the left side of the recording head H, second nozzles with odd Seg numbers are arranged at 600 dpi intervals and are responsible for recording pixels at pixel positions Yo (o is an odd number) among pixel positions Y0 to Y19.

[0083] 14B is a diagram showing which nozzles are responsible for which pixel positions among the nozzles arranged in the print head H. The first nozzle is responsible for the pixel positions marked with an "E" in the diagram, and the second nozzle is responsible for the pixel positions marked with an "O" in the diagram.

[0084] FIG. 14C is a diagram showing the results of edge processing detected by the edge detection process. A first edge region and a second edge region are detected by the edge detection process flow described above. In FIG. 14C, pixel positions marked with "1" indicate pixel positions of pixels determined to be the first edge region in the edge detection process, and pixel positions marked with "2" indicate pixel positions of pixels determined to be the second edge region in the edge detection process. Pixel positions marked with "0" indicate pixel positions of pixels determined to be a non-edge region in the edge detection process.

[0085] FIG. 14D is a diagram related to the thinning process of the print data arranged in the first edge region and the second edge region. Of the pixels determined to be in the first edge region, the pixels to be printed with ink droplets from the first nozzle (pixels at pixel positions marked with "E" in FIG. 14B) are targeted for thinning. Also, of the pixels determined to be in the second edge region, the pixels to be printed with ink droplets from the second nozzle (pixels at pixel positions marked with "O" in FIG. 14B) are targeted for thinning. The pixels at pixel positions marked with "x" in FIG. 14D are targeted for thinning, and ink is not ejected. Of the pixel positions marked with "0", "1", and "2" in FIG. 14C, pixels other than the pixels to be thinned (non-thinned pixels) are marked with "●". Non-thinned pixels are pixels to which ink is ejected.

[0086] Such settings of the thinning targets are stored in advance in the ROM 206 or the like. When generating print data, the printhead control unit 213 sets "pixels determined to be in the first edge region and to be printed with ink droplets from the first nozzle" and "pixels determined to be in the second edge region and to be printed with ink droplets from the second nozzle" as thinning targets based on the settings. In other words, the printhead control unit 213 generates print data from an input image that determines whether or not to eject ink droplets from a printhead having a first nozzle array and a second nozzle array in which the relative relationship between the landing positions of main droplets and satellites ejected from the first nozzle array is different. At that time, the printhead control unit 213 sets, as thinning targets, pixels printed by the nozzles of the first nozzle array among the pixels of the first edge region on the object side adjacent to the boundary where the object changes to the paper white region in the first scanning direction of the printhead. Similarly, among the pixels in the second edge region on the object side adjacent to the boundary where the object changes to the paper white region in a second scanning direction opposite to the first scanning direction of the print head, the pixels printed by the nozzles of the second nozzle array are set as thinning targets. No ink is ejected onto the pixels set as thinning targets.

[0087] In this embodiment, the purpose is to reduce the usage ratio of nozzles that generate many satellites around the edges in the printing of the first edge region and the second edge region. The present invention is not limited to the print data generation method in which all relevant pixels are thinned out as shown in the print data generation described above.

[0088] 15(a) shows a print result when the character "a" is printed in the first scanning direction based on print data that does not undergo edge processing according to this embodiment. The first edge region, which is located in the front when viewed in the first scanning direction, is printed by the first nozzle row, in which the distance between the main droplet and the satellite is relatively long, and the second nozzle row, in which the distance between the main droplet and the satellite is relatively short. Since the satellites flying from the first nozzle row fly in the direction of carriage travel, the first edge region appears blurred, impairing the image quality (print quality) of the characters and lines.

[0089] 15(b) shows a print result when the character "a" is printed in the second scanning direction based on print data that does not undergo edge processing according to this embodiment. The second edge region, which is located in the front when viewed in the second scanning direction, is printed by the first nozzle row, in which the distance between the main droplet and the satellite is relatively short, and the second nozzle row, in which the distance between the main droplet and the satellite is relatively long. Since the satellites flying from the second nozzle row fly in the direction of carriage travel, the second edge region appears blurred, impairing the image quality (print quality) of the characters and lines.

[0090] 15(c) shows a print result when the letter "a" is printed in the first scanning direction based on print data generated by this embodiment. The first edge region located in the front when viewed in the first scanning direction is printed by the second nozzle row, in which the distance between the main droplets and the satellites is relatively short, and the first nozzle row, in which the distance between the main droplets and the satellites is relatively long, is not used. The second edge region located in the rear in the first scanning direction is printed by the first nozzle row, and the second nozzle row is not used. The satellites fly in the direction of carriage travel, so they overlap with the non-edge region and are not recognized as a problem.

[0091] FIG. 15(d) shows a print result when the character "a" is printed in the second scanning direction based on the print data generated by this embodiment. The second edge region located in the front when viewed in the second scanning direction is printed by the first nozzle row in which the distance between the main droplets and the satellites is relatively short, and the second nozzle row in which the distance between the main droplets and the satellites is relatively long is not used. The first edge region located in the rear in the second scanning direction is printed by the second nozzle row, and the first nozzle row is not used. The satellites fly in the direction of carriage travel, so they overlap with the non-edge region and are not recognized as a problem. The satellites fly in the direction of carriage travel, so they overlap with the non-edge region and are not recognized as a problem.

[0092] FIG. 16 shows an example of the result of printing on a recording medium by repeating a plurality of recording scans by the carriage and conveyance of the recording medium based on recording data that has not been subjected to the edge processing of this embodiment.

[0093] First, the carriage is scanned in a first scanning direction to print based on the recording data in the first band area. After printing based on all the recording data in the first band area is completed, the recording medium is transported by the recording medium transport (first transport) to make it possible to print on the second band area.

[0094] Next, the carriage is scanned in the first scanning direction to print based on the recording data in the second band area. After printing based on all the recording data in the second band area is completed, the recording medium is transported by the recording medium transport (second transport) to make it possible to print on the third band area.

[0095] Next, the carriage is scanned in the second scanning direction to print based on the recording data in the third band area. After printing based on all the recording data in the third band area is completed, the recording medium is transported by the recording medium transport (third transport) to make it possible to print on the fourth band area.

[0096] Finally, the carriage is scanned in the first scanning direction to perform printing based on all the recording data in the fourth band area.

[0097] As described above, the print result recorded in the first and second scanning directions using recording data that has not undergone the edge processing of this embodiment has noticeable satellite flying around the edges, resulting in a decrease in the print quality of lines and characters. In addition, when multiple recording data are selected according to a scanning direction (not shown), this leads to a decrease in image uniformity between adjacent printing areas and a decrease in throughput.

[0098] FIG. 17 shows an example of the result of printing on a recording medium by repeating a plurality of recording scans by the carriage and conveyance of the recording medium based on the recording data on which edge processing has been performed in this embodiment.

[0099] First, the carriage is scanned in a first scanning direction to print based on the recording data in the first band area. After printing based on all the recording data in the first band area is completed, the recording medium is transported by the recording medium transport (first transport) to make it possible to print on the second band area.

[0100] Next, the carriage is scanned in the first scanning direction to print based on the recording data in the second band area. After printing based on all the recording data in the second band area is completed, the recording medium is transported by the recording medium transport (second transport) to make it possible to print on the third band area.

[0101] Next, the carriage is scanned in the second scanning direction to print based on the recording data in the third band area. After printing based on all the recording data in the third band area is completed, the recording medium is transported by the recording medium transport (third transport) to make it possible to print on the fourth band area.

[0102] Finally, the carriage is scanned in the first scanning direction to perform printing based on all the recording data in the fourth band area.

[0103] As described above, the print result recorded in the first and second scanning directions (reciprocating scans) using the print data generated by the edge processing of this embodiment can achieve high-quality printing of lines and characters with less noticeable flying satellites around the edges. In addition, since the print data generated by this embodiment does not require the selection of multiple print data according to the scanning direction, the time required to generate the print data can be reduced.

[0104] As a result, in a recording head configuration having flight characteristics in which the relative landing distance of satellites accompanying the main droplets of ink ejected varies depending on the scanning direction, it is possible to achieve high-quality printing of lines and characters while suppressing a decrease in image uniformity between adjacent printing areas and a deterioration in throughput.

[0105] [Second embodiment] The following describes the differences from the first embodiment, and unless otherwise specified, it is assumed that the second embodiment is the same as the first embodiment. Fig. 18 shows the configuration of the print head used in this embodiment.

[0106] FIG. 18(a) shows a black nozzle row, in which a first nozzle row and a second nozzle row are arranged at symmetrical positions in the X direction with respect to an ink flow path 2201. A heater 2203 for ejection is arranged directly below (on the +Z direction side) each nozzle. When a voltage is applied, the heater 2203 generates heat to generate bubbles, causing ink to be ejected from each nozzle. In the first nozzle row and the second nozzle row, 832 nozzles 2202 are arranged in the Y direction at a pitch of 1200 dpi. The first nozzle row and the second nozzle row are arranged in parallel positions in the X direction, and by performing a print scan using the black nozzle row configured in this way, it is possible to print on the print medium at a print resolution of 1200 dpi in the Y direction.

[0107] The printing density in the X direction is such that the first nozzle row and the second nozzle row each eject ink at a resolution of 600 dpi in the carriage scanning direction, and either the first nozzle row or the second nozzle row is used, or droplets are fired from both the first nozzle row and the second nozzle row, thereby achieving a printing resolution of 600 dpi on the printing medium.

[0108] FIG. 18(b) shows one of the color nozzle arrays, with the first and second nozzle arrays arranged at symmetrical positions in the X direction with the ink flow path 2204 at the center. A heater 2206 for ejection is arranged directly below (on the +Z direction side) each nozzle. When a voltage is applied to the heater 2206, it generates heat to generate bubbles, causing ink to be ejected from each nozzle. In the first and second nozzle arrays, 832 nozzles 2205 are arranged in the Y direction at a pitch of 1200 dpi. The first and second nozzle arrays are arranged in parallel positions in the X direction, and by performing a print scan using the color nozzle arrays arranged in this way, it is possible to print on the print medium at a print resolution of 1200 dpi in the Y direction.

[0109] The above is the content of the recording head structure used in the second embodiment.

[0110] <Print Data Generation in This Embodiment> 19A to 19D are diagrams for explaining image processing applied to the first edge region and the second edge region detected by the edge detection process described above in this embodiment. Fig. 19A is a diagram showing a print head H and "print data for a print resolution of 600 dpi in the X direction and 1200 dpi in the Y direction" which is the result of quantization of an input image. X0 to X19 in the diagram represent pixel positions corresponding to the carriage scanning direction, and Y0 to Y19 in the diagram represent pixel positions corresponding to the print medium transport direction. The downward direction in the diagram is the paper feed direction.

[0111] In the Y direction, the "first nozzles with Seg numbers 0 to 19 arranged at 1200 dpi intervals" and the "second nozzles with Seg numbers 0 to 19 arranged at 1200 dpi intervals" arranged on the print head H are responsible for printing the pixels at pixel positions Y0 to Y19.

[0112] On the other hand, in the X direction, the first nozzle with an odd Seg number in the first nozzle row and the second nozzle with an even Seg number in the second nozzle row are responsible for recording pixels at pixel positions Ye (e is an even number) among pixel positions X0 to X19. Also, the first nozzle with an even Seg number in the first nozzle row and the second nozzle with an odd Seg number in the second nozzle row are responsible for recording pixels at pixel positions Yo (o is an odd number) among pixel positions X0 to X19. As a result, it is possible to print on the recording medium with a recording resolution of 600 dpi in the carriage scanning direction.

[0113] 19B is a diagram showing which nozzles are responsible for which pixel positions among the nozzles arranged in the print head H. The first nozzle is responsible for the pixel positions marked with an "E" in the diagram, and the second nozzle is responsible for the pixel positions marked with an "O" in the diagram.

[0114] FIG. 19C is a diagram showing the results of edge processing detected by edge detection processing. A first edge region and a second edge region are detected by the edge processing flow described above. In FIG. 19C, pixel positions marked with "1" indicate pixel positions of pixels determined to be the first edge region in the edge detection processing, and pixel positions marked with "2" indicate pixel positions of pixels determined to be the second edge region in the edge detection processing. Pixel positions marked with "0" indicate pixel positions of pixels determined to be a non-edge region in the edge detection processing.

[0115] FIG. 19D is a diagram related to the thinning process of print data arranged in the first edge region and the second edge region. Of the pixels determined to be in the first edge region, the pixels to be printed with ink droplets from the first nozzle (pixels at pixel positions marked with "E" in FIG. 19B) are targeted for thinning. Also, of the pixels determined to be in the second edge region, the pixels to be printed with ink droplets from the second nozzle (pixels at pixel positions marked with "O" in FIG. 19B) are targeted for thinning. The pixels at pixel positions marked with "x" in FIG. 19D are targeted for thinning, and ink is not ejected. Of the pixel positions marked with "0", "1", and "2" in FIG. 19C, pixels other than the pixels to be thinned (non-thinned pixels) are marked with "●". Non-thinned pixels are pixels to which ink is ejected.

[0116] In this embodiment, the printhead control unit 213 generates print data in the same manner as in the first embodiment. The above is the content of the first print data generation used in the second embodiment.

[0117] In this embodiment, the object is to reduce the usage ratio of nozzles that generate many satellites around the edges in printing the first edge region and the second edge region. The present invention is not limited to the print data generation method that thins out the corresponding pixels as shown in the first print data generation.

[0118] Here, the second print data generation of this embodiment will be described. In FIG. 19B, the pixel indicated by "E" and in FIG. 19C indicated by "1" is the pixel to be printed by the second nozzle. The second nozzle prints the pixel position indicated by "O" in the figure. On the other hand, the pixel indicated by "O" in FIG. 19B and in FIG. 19C indicated by "2" is the pixel to be printed by the first nozzle. The first nozzle prints the pixel position indicated by "E" in the figure. As a result, the nozzle to be used for printing each pixel is determined as shown in FIG. 22.

[0119] As described above, the second print data is generated to assign nozzles for printing the first edge region and the second edge region. As a result, in printing around the edges, the usage ratio of nozzles with relatively high satellite flying can be reduced.

[0120] The print results when the first print data and the second print data used in this embodiment are generated are the same as those described in the first embodiment using Figures 15(c) and 15(d), so they will not be described here. Also, the carriage scanning direction in this embodiment and the print results formed on the print medium are the same as those described in the first embodiment using Figure 17, so they will not be described here.

[0121] As described above, the print result recorded in the first and second scanning directions using the recording data generated by the edge processing of this embodiment can achieve high-quality printing of lines and characters with little satellite flying around the edges. In addition, since the recording data generated in this embodiment does not require the selection of multiple recording data according to the scanning direction, the time required to generate the recording data can be reduced.

[0122] As a result, in a recording head configuration having flight characteristics in which the relative landing distance of satellites accompanying the main droplets of ink ejected varies depending on the scanning direction, it is possible to achieve high-quality printing of lines and characters while suppressing a decrease in image uniformity between adjacent printing areas and a deterioration in throughput.

[0123] (Exception handling) In the first and second embodiments, an example was shown in which satellites were suppressed from flying around the edges by thinning out the pixels of the nozzles with many satellites flying in accordance with the carriage scanning direction for the first edge region and the second edge region detected by edge detection. When generating print data by thinning out in this way, for example, thinning out the edge region with a narrow ruled line of 1 dot width at 600 dpi reduces the density of the line, reducing the visibility of the line.

[0124] Therefore, if the line width is less than a predetermined value, it is possible to perform exceptional processing in which the pixels are not detected as first edge regions or second edge regions and are not thinned out. In other words, a specified number of consecutive pixels in the carriage scanning direction are thinned out, and consecutive pixels in the carriage scanning direction that are less than the specified number are not thinned out. Also, a specified number of consecutive pixels in the recording medium transport direction are thinned out, and consecutive pixels in the recording medium transport direction that are less than the specified number are not thinned out.

[0125] As described above, in this embodiment, edge processing for a specific color having flight characteristics in which the relative landing distances of satellites accompanying main droplets of ink ejected according to the scanning direction differ has been described. However, when the flight characteristics differ for each color, the edge detection conditions and edge processing contents may be changed according to the respective flight characteristics.

[0126] In addition, since the flight characteristics of ink droplets depend on ejection conditions such as the ink refill speed and ejection frequency, and printing conditions such as the carriage scanning speed and paper distance, the edge detection conditions and edge processing contents may be changed depending on the selected print command.

[0127] In addition, in this embodiment, a one-pass mode is used to print an image by performing a single scan of the print head over a unit area on the print medium, but a similar effect can also be obtained in a multi-pass mode in which an image is printed over a unit area by performing multiple scans of the print head.

[0128] As described above, the characteristics of satellites differ depending on whether the scanning direction is the first scanning direction or the second scanning direction. In the scanning in the first scanning direction, when the first edge region is printed by the first nozzle row, the satellites are easily noticeable in the printed image. Similarly, in the scanning in the second scanning direction, when the second edge region is printed by the second nozzle row, the satellites are easily noticeable in the printed image. In this embodiment, pixels in which satellites are easily noticeable in the printed image are targeted for thinning. However, in both the one-pass mode and the multi-pass mode, if the direction of the scanning in which each pixel in the first edge region and the second edge region is printed is not determined, it is not possible to know whether the pixel is one in which satellites are easily noticeable. Therefore, regardless of the direction of the scanning in which each pixel is printed, the pixels in the first edge region that are printed by the nozzles of the first nozzle row and the pixels in the second edge region that are printed by the nozzles of the second nozzle row are targeted for thinning in advance. This makes it possible to prevent degradation of image quality due to satellites in the recorded image, regardless of whether the scanning actually performed is in the first scanning direction or the second scanning direction.

[0129] This makes it possible to handle irregular movements such as when the print head is forced to turn around and scan, for example, when there is a blank area where no image is printed, or when an image is placed in only a part of the print medium. Since generating binary data according to the direction each time this occurs reduces the printing throughput, by generating print data in advance that does not generate satellites, it is possible to suppress degradation of image quality regardless of the print head movement.

[0130] Also, as described above, it is not necessary to thin out all of the pixels in the first edge region that are printed by the nozzles of the first nozzle row and all of the pixels in the second edge region that are printed by the nozzles of the second nozzle row. All that is required is to make the ratio of pixels in the first edge region that are printed by the nozzles of the first nozzle row lower than the ratio of pixels in the second nozzle row. Also, it is sufficient to make the ratio of pixels in the second edge region that are printed by the nozzles of the second nozzle row lower than the ratio of pixels in the first nozzle row.

[0131] In addition, in this embodiment, a printing method has been described in which the print head prints and scans in either the first scanning direction or the second scanning direction, but the same effect can be obtained in a single scanning direction mode in which printing is performed only in the first scanning direction or only in the second scanning direction.

[0132] In the first and second embodiments, only edge regions are thinned out. However, N pixels may be thinned out toward the inside of an object (the letter "a" in the above example) that includes an edge region according to the carriage movement speed. In this case, N may be preset to be larger as the carriage movement speed increases.

[0133] Each functional unit of the image processing unit 208 may be implemented by hardware, or part or all of the functional units may be implemented by software (computer programs). In the latter case, the computer programs are stored in the ROM 206, and the CPU 203 executes the computer programs to realize the functions of the corresponding functional units.

[0134] The numerical values, processing timing, processing order, processing subject, data (information) acquisition method / destination / source / storage location, etc. used in each of the above embodiments are given as examples to provide a concrete explanation, and are not intended to be limited to these examples.

[0135] In addition, a part or all of the embodiments described above may be used in appropriate combination. In addition, a part or all of the embodiments described above may be used selectively.

[0136] (Other embodiments) The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0137] The invention of this specification includes the following image processing device, image processing method, and computer program. (Item 1) An image processing device, An acquisition means for acquiring an input image including a target object; a generating means for generating recording data indicating whether or not ink droplets are applied from a recording means based on the input image; Equipped with the recording means has a first recording element array and a second recording element array in which recording elements for applying ink droplets are arranged, and scans reciprocally in a first direction and a second direction opposite to the first direction; a ratio of pixels recorded by one or more recording elements included in the first recording element array among a plurality of pixels included in a first edge region of the target object is smaller than a ratio of pixels recorded by one or more recording elements included in the second recording element array; the first edge region is a region adjacent to a boundary where an object changes into a blank region of a recording medium when viewed in the first direction; a ratio of pixels recorded by one or more recording elements included in the second recording element array among a plurality of pixels included in a second edge region of the target object is smaller than a ratio of pixels recorded by one or more recording elements included in the first recording element array; The second edge region is a region adjacent to a boundary where an object changes into a blank region of a recording medium when viewed in the second direction. 13. An image processing device comprising: (Item 2) The image processing device described in item 1, characterized in that the generation means reduces pixels recorded by one or more recording elements included in the first recording element array in the first edge region, and reduces pixels recorded by one or more recording elements included in the second recording element array in the second edge region. (Item 3) the number of pixels recorded by one or more recording elements included in the first recording element array in the first edge region is 0; In the second edge region, the number of pixels recorded by one or more recording elements included in the second recording element array is 0. 2. The image processing device according to item 1, (Item 4) 2. The image processing device according to item 1, further comprising a detection unit for detecting the first edge region and the second edge region of the target object from an input image. (Item 5) 5. The image processing device according to item 4, wherein the detection means does not detect the first edge region and the second edge region of an object in which the number of consecutive pixels in the first direction is less than a predetermined number. (Item 6) 5. The image processing device according to item 4, wherein the detection means does not detect the first edge area and the second edge area of ​​an object having a number of consecutive pixels less than a predetermined number in a transport direction of the recording medium that intersects with the first direction. (Item 7) 2. The image processing apparatus according to item 1, wherein in the recording means, the first recording element array and the second recording element array are supplied with ink from a same liquid chamber. (Item 8) 8. The image processing apparatus according to item 7, wherein in the recording means, the first recording element array is located forward of the second recording element array in the first direction, with the liquid chamber therebetween. (Item 9) 2. The image processing apparatus according to item 1, wherein the first recording element array is positioned forward of the second recording element array in the first direction. (Item 10) 2. The image processing device according to item 1, wherein the first recording element array and the second recording element array are supplied with ink from a common flow path. (Item 11) An image processing method performed by an image processing device, comprising: an acquisition step in which an acquisition means of the image processing device acquires an input image including a target object; a generation step in which a generation means of the image processing apparatus generates recording data indicating whether or not ink droplets are applied from a recording means based on the input image; Equipped with the recording means has a first recording element array and a second recording element array in which recording elements for applying ink droplets are arranged, and scans reciprocally in a first direction and a second direction opposite to the first direction; a ratio of pixels recorded by one or more recording elements included in the first recording element array among a plurality of pixels included in a first edge region of the target object is smaller than a ratio of pixels recorded by one or more recording elements included in the second recording element array; the first edge region is a region adjacent to a boundary where an object changes into a blank region of a recording medium when viewed in the first direction; a ratio of pixels recorded by one or more recording elements included in the second recording element array among a plurality of pixels included in a second edge region of the target object is smaller than a ratio of pixels recorded by one or more recording elements included in the first recording element array; The second edge region is a region adjacent to a boundary where an object changes into a blank region of a recording medium when viewed in the second direction. 13. An image processing method comprising: (Item 12) A computer program for causing a computer to function as each of the means of the image processing device according to any one of items 1 to 10.

[0138] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0139] 2: Printer 10: Image forming apparatus 100: Image processing apparatus 201: Host computer 202: Scanner 203: CPU 204: Host IF control section 205: Scanner IF control section 206: ROM 207: RAM 208: Image processing section 209: Decoder section 210: Image analysis section 211: Color separation and quantization section 212: Nozzle separation section 213: Head control section 215: Shared bus 216: Scan image correction section

Claims

1. An image processing device, An acquisition means for acquiring an input image including a target object; a generating means for generating recording data indicating whether or not ink droplets are applied from a recording means based on the input image; Equipped with the recording means includes a first recording element array and a second recording element array in which recording elements for applying ink droplets are arranged, and the recording means reciprocates in a first direction and a second direction opposite to the first direction; a ratio of pixels recorded by one or more recording elements included in the first recording element array among a plurality of pixels included in a first edge region of the target object is smaller than a ratio of pixels recorded by one or more recording elements included in the second recording element array; the first edge region is a region adjacent to a boundary where an object changes into a margin region of a recording medium when viewed in the first direction; a ratio of pixels recorded by one or more recording elements included in the second recording element array among a plurality of pixels included in a second edge region of the target object is smaller than a ratio of pixels recorded by one or more recording elements included in the first recording element array; The second edge region is a region adjacent to a boundary where an object changes into a blank region of a recording medium when viewed in the second direction.

13. An image processing device comprising:

2. 2. The image processing device according to claim 1, characterized in that the generation means reduces pixels printed by one or more printing elements included in the first printing element array in the first edge region, and reduces pixels printed by one or more printing elements included in the second printing element array in the second edge region.

3. in the first edge region, the number of pixels recorded by one or more recording elements included in the first recording element array is 0; In the second edge region, the number of pixels recorded by one or more recording elements included in the second recording element array is 0.

2. The image processing device according to claim 1,

4. 2 . The image processing apparatus according to claim 1 , further comprising a detection unit for detecting the first edge region and the second edge region of the target object from an input image.

5. 5. The image processing device according to claim 4, wherein the detection means does not detect the first edge region and the second edge region of an object in which the number of consecutive pixels in the first direction is less than a predetermined number.

6. 5. The image processing device according to claim 4, wherein the detection means does not detect the first edge area and the second edge area of ​​an object in which the number of consecutive pixels in a transport direction of the recording medium that intersects with the first direction is less than a predetermined number.

7. 2. The image processing apparatus according to claim 1, wherein in said recording means, said first recording element array and said second recording element array are supplied with ink from a same liquid chamber.

8. 8. The image processing apparatus according to claim 7, wherein in said recording means, said first recording element array is located forward of said second recording element array in said first direction, with said liquid chamber interposed therebetween.

9. 2 . The image processing apparatus according to claim 1 , wherein the first recording element array is positioned forward of the second recording element array in the first direction.

10. 2. The image processing apparatus according to claim 1, wherein the first recording element array and the second recording element array are supplied with ink from a common flow path.

11. An image processing method performed by an image processing device, comprising: an acquisition step in which an acquisition means of the image processing device acquires an input image including a target object; a generation step in which a generation means of the image processing apparatus generates recording data indicating whether or not ink droplets are applied from a recording means based on the input image; Equipped with the recording means includes a first recording element array and a second recording element array in which recording elements for applying ink droplets are arranged, and the recording means reciprocates in a first direction and a second direction opposite to the first direction; a ratio of pixels recorded by one or more recording elements included in the first recording element array among a plurality of pixels included in a first edge region of the target object is smaller than a ratio of pixels recorded by one or more recording elements included in the second recording element array; the first edge region is a region adjacent to a boundary where an object changes into a margin region of a recording medium when viewed in the first direction; a ratio of pixels recorded by one or more recording elements included in the second recording element array among a plurality of pixels included in a second edge region of the target object is smaller than a ratio of pixels recorded by one or more recording elements included in the first recording element array; The second edge region is a region adjacent to a boundary where an object changes into a blank region of a recording medium when viewed in the second direction.

13. An image processing method comprising:

12. A computer program for causing a computer to function as each of the means of the image processing apparatus according to any one of claims 1 to 10.

Images