Inkjet printing method, device and equipment based on image component concentration relationship curve

Abstract

The present invention discloses an inkjet printing method, device and equipment based on an image component concentration relationship curve, relating to the technical field of inkjet printing. The method obtains the number of scans N required for printing a unit area of the image to be printed, obtains N image components of the image to be printed according to the number of scans N, performs screening processing on the N image components respectively according to the corresponding concentration relationship curves to obtain N pieces of printing data, and finally inkjet prints the image to be printed according to the N pieces of printing data, so that the ink dot distribution is more uniform, the image precision is improved while the problem of white showing in the areas with relatively light concentration is solved, and the image printing quality is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of inkjet printing, and in particular to an inkjet printing method, apparatus, and device based on an image component concentration relationship curve. Background Art

[0002] Inkjet printing technology refers to jetting ink droplets onto a printing medium through nozzles on a print head to obtain an image or text, mainly including multi-PASS scanning printing, One-PASS high-speed printing, etc. In multi-PASS scanning printing, the image to be printed is divided into several unit areas during printing, and each unit area is completed through multiple scans. For example, if the unit area of the image to be printed requires 4 PASSes to complete printing, it is called 4-PASS scanning printing. Exemplarily, as Figure 1a shown in the schematic diagram of 4-PASS printing (the number of scans is 4, where the number of horizontal scans is 2 and the number of vertical scans is 2) for the image to be printed. The image to be printed consists of pixels corresponding to many pixel positions ①②③④. Taking a group of pixel positions ①②③④ as a unit area, in the first PASS, the print head moves along the main scanning direction and inkjet prints pixel position ①, then the print head and the printing medium move relative to each other by a certain distance, the print head moves in the reverse direction along the main scanning direction and inkjet prints pixel position ②, then the print head and the printing medium move relative to each other by a certain distance, the print head moves along the main scanning direction again and inkjet prints pixel position ③, after the print head and the printing medium move relative to each other by a certain distance, it moves in the reverse direction again and inkjet prints pixel position ④, and so on for repeated printing until the printing is completed.

[0003] During printing, the image to be printed is first screened to obtain the original printing data, and then the printing data for each PASS (scan) is split from the original printing data for reciprocating scanning printing. However, the uniformity of the printing data split from the original printing data is poor, with some areas having denser ink dots and some areas having sparser ink dots, resulting in a poor uniformity of the final printed image. To solve this problem, a method is proposed to first split the image data to be printed according to the number of PASSes (number of scans) (the image to be printed can be divided into four different image components according to pixel positions ①②③④, that is, split according to different image components ①②③④), and then screen the split image components respectively to obtain the corresponding printing data. In this way, printing according to the printing data of each image component can solve the problem of denser ink dots in some areas and sparser ink dots in some areas. But because the screening of each image component starts from a concentration of 0, the dot pattern of the image to be printed obtained has messy dots in the areas with lighter concentrations (such as Figure 1bAs shown, when printing, the ink dots will be rather messy (when printing, each image component starts to print ink dots gradually from the point where the concentration is 0), resulting in the phenomenon of white spots easily occurring in the printed image, thus affecting the quality of image printing. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide an inkjet printing method, apparatus and device based on the concentration relationship curve of image components to solve the problem of white spots easily occurring in areas with relatively light concentration.

[0005] In a first aspect, an embodiment of the present invention provides an inkjet printing method based on the concentration relationship curve of image components, and the method includes:

[0006] Obtain the number of scans N required to complete the printing of a unit area of the image to be printed, where N is a natural number greater than or equal to 2;

[0007] Obtain N image components of the image to be printed according to the number of scans N;

[0008] Obtain the corresponding concentration relationship curve for each of the image components, where the concentration relationship curve is the relationship curve between the concentration of the image component and the concentration of the image to be printed;

[0009] Perform screening processing on the N image components respectively according to the corresponding concentration relationship curves to obtain N pieces of printing data;

[0010] Inkjet print the image to be printed according to the N pieces of printing data.

[0011] Preferably, the obtaining of the corresponding concentration relationship curve for each of the image components includes:

[0012] Establish a two-dimensional coordinate system with the concentration of the image to be printed as the horizontal axis and the concentration of the image component as the vertical axis;

[0013] Obtain the preset starting point and preset reference point of the concentration relationship curve of each of the image components;

[0014] Obtain the concentration relationship curve of each of the image components according to the preset starting point and the preset reference point.

[0015] Preferably, the preset starting point coordinates of the concentration relationship curves of the N image components are respectively: (T 1 , 0), (T 2 , 0),..., (T N , 0), where the values of T1, T2,..., T N are one of the following:

[0016] T 1 = 0 and T 1 < T2 <……<T N ≤X;

[0017] T 1 = 0 and T 1 <T 2 = T 3 =……= T N ≤X;

[0018] T 1 = T 2 =……= T N-1 = 0 and T N-1 <T N ≤X;

[0019] T 1 <T 2 <……<T N ≤X and T i –T i-1 = T i-1 -T i-2 where i = 2,……, N;

[0020] where X is a preset concentration threshold.

[0021] Preferably, after obtaining the concentration relationship curve of each of the image components according to the preset starting point and the preset reference point, the method further includes:

[0022] Smoothing the curve part within a preset range of the starting point of the concentration relationship curve.

[0023] Preferably, the screening process includes any one of frequency modulation screening, amplitude modulation screening, 1Bit screening, 2bit screening, three-segment screening, and hybrid screening.

[0024] Preferably, the screening methods of several copies of the printing data are the same or different.

[0025] In a second aspect, an embodiment of the present invention provides an inkjet printing apparatus based on a concentration relationship curve of an image component, the apparatus includes:

[0026] A scanning times acquisition module, configured to acquire the number of scanning times N required to complete printing of a unit area of an image to be printed, where N is a natural number greater than or equal to 2;

[0027] An image component acquisition module, configured to acquire N image components of the image to be printed according to the number of scanning times N;

[0028] A concentration relationship curve acquisition module, configured to acquire a corresponding concentration relationship curve for each of the image components, where the concentration relationship curve is a curve of the relationship between the concentration of the image component and the concentration of the image to be printed;

[0029] A screening module, configured to perform screening processing on each of the N image components according to the corresponding density relationship curve to obtain N pieces of printing data;

[0030] A printing module, configured to ink-jet print the image to be printed according to the N pieces of printing data.

[0031] In a third aspect, an embodiment of the present invention provides an ink-jet printing device based on an image component density relationship curve, including: at least one processor, at least one memory, and computer program instructions stored in the memory, which implement the method of the first aspect in the above-mentioned embodiment when the computer program instructions are executed by the processor.

[0032] In a fourth aspect, an embodiment of the present invention provides a storage medium, on which computer program instructions are stored, which implement the method of the first aspect in the above-mentioned embodiment when the computer program instructions are executed by the processor.

[0033] In summary, the beneficial effects of the present invention are as follows:

[0034] The ink-jet printing method, device and equipment based on the image component density relationship curve provided by the embodiment of the present invention obtain the number of scans N required to complete the printing of a unit area of the image to be printed, obtain N image components of the image to be printed according to the number of scans N, and perform screening processing on each of the N image components according to the corresponding density relationship curve to obtain N pieces of printing data, and finally ink-jet print the image to be printed according to the N pieces of printing data, so that the distribution of ink dots is more uniform, improving the image accuracy while solving the problem of white exposure in areas with relatively light density, and improving the image printing quality. Description of the Drawings

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to these drawings, and these are all within the protection scope of the present invention.

[0036] Figure 1a It is a schematic diagram of 4PASS printing in the background technology.

[0037] Figure 1b It is a dot pattern of an area with relatively light density in the image to be printed in the background technology.

[0038] Figure 2 It is a schematic diagram of reciprocating scanning ink-jet printing in Embodiment 1 of the present invention.

[0039] Figure 3a It is a schematic diagram of the nozzle 1 in Embodiment 1 of the present invention.

[0040] Figure 3b It is a schematic diagram of the nozzle group 2 in the first embodiment of the present invention.

[0041] Figure 4 It is a schematic diagram of the nozzle group 5 in the first embodiment of the present invention.

[0042] Figure 5 It is a schematic flow diagram of inkjet printing based on the image component concentration relationship curve in the second embodiment of the present invention.

[0043] Figure 6 It is a schematic diagram of four image components of the image to be printed in the second embodiment of the present invention.

[0044] Figure 7a It is a schematic diagram of the concentration relationship curve in the second embodiment of the present invention.

[0045] Figure 7b It is a schematic diagram of the concentration relationship curve in the second embodiment of the present invention.

[0046] Figure 7c It is a schematic diagram of the concentration relationship curve in the second embodiment of the present invention.

[0047] Figure 8 It is a schematic diagram of the concentration relationship curve in the second embodiment of the present invention.

[0048] Figure 9 It is a dot pattern of the area with relatively light concentration in the image to be printed in the second embodiment of the present invention.

[0049] Figure 10 It is a schematic structural diagram of the inkjet printing device based on the image component concentration relationship curve in the second embodiment of the present invention.

[0050] Figure 11 It is a schematic structural diagram of the inkjet printing equipment based on the image component concentration relationship curve in the second embodiment of the present invention. Detailed implementation manners

[0051] The features and exemplary embodiments of various aspects of the present invention will be described in detail below. In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and are not configured to limit the present invention. For those skilled in the art, the present invention can be implemented without some of these specific details. The following description of the embodiments is only provided to provide a better understanding of the present invention by showing examples of the present invention.

[0052] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0053] Embodiment 1

[0054] An embodiment of the present invention provides an inkjet printing method, which is applicable to a reciprocating scanning inkjet printer. The printer at least includes a print head, and the print head at least includes a column of nozzles for inkjet printing.

[0055] The inkjet printing method provided by the embodiment of the present invention specifically includes the following steps:

[0056] Obtain the original printing accuracy, the number of scans, and the single-channel accuracy of the image to be printed;

[0057] Perform halftoning on the image to be printed according to the number of scans and the original printing accuracy and / or the single-channel accuracy to obtain several pieces of printing data;

[0058] Inkjet print the image to be printed according to several pieces of the printing data.

[0059] As Figure 2 shown is a schematic diagram of reciprocating scanning inkjet printing. During printing, the print carriage installed with the print head moves once from left to right or from right to left along the main scanning direction as one Pass. Between each Pass, the print medium and the print carriage move a certain distance relative to each other along the sub-scanning direction, and this distance is the paper feed distance.

[0060] When the printing precision of the image to be printed is higher than the precision of the print head, multi-Pass printing is required to achieve the printing precision of the image to be printed. Before printing the image to be printed, screening processing or halftone processing needs to be performed on the image to be printed. Here, the image to be printed is a continuous-tone image. After screening processing, the print data recognizable by the printer is obtained. The screening processing methods here include frequency modulation screening, amplitude modulation screening, 1Bit screening, 2bit screening, three-segment screening, hybrid screening, etc. Among them, 1bit screening means that the print data obtained after screening the image to be printed only includes "1" or "0", where "1" indicates ink output and "0" indicates no ink output; 2bit screening means that the print data obtained after screening the image to be printed includes "00", "01", "10" and "11", where "00" indicates no ink output, "01" indicates small dot output, "10" indicates medium dot output, and "11" indicates large dot output. Three-segment screening means that when the image density n ≤ X1, the print data is entirely expressed by empty dots and small dots, and the small dot density gradually changes from 0 to 100%, when X1 < n ≤ X2, it is entirely expressed by small dots and medium dots, and the medium dot density gradually changes from 0 to 100%, and when n > X2, it is entirely expressed by medium dots and large dots, and the large dot density changes from 0 to 100%. The values of X1 and X2 can be set according to the actual situation.

[0061] Hybrid screening means that when the image density reaches X1, it is only expressed by empty dots and small dots, and after reaching X1, medium dots are gradually added and expressed by empty dots, small dots and medium dots, and after the density reaches X2, large dots are gradually added and expressed by empty dots, small dots, medium dots and large dots. The values of X1 and X2 can be set according to the actual situation, and the above numbers are only examples given to clearly reveal the technical principle and do not limit the present invention. Any numbers or symbols that conform to this principle are included in the scope of the present invention.

[0062] The image precision of the image to be printed is called the original printing precision. After screening the image to be printed according to the original printing precision, the print data of the image to be printed is obtained. In the prior art, the printer divides the print data of the image to be printed into several Pass print data according to the print head precision and the firing frequency, and distributes each Pass print data to the corresponding print head for each Pass printing. In the present invention, instead of obtaining a single print data by screening processing according to the original printing precision, the image to be printed is screened according to the single-channel precision or the printing precision of each scan to obtain several uniform print data. Among them, these several print data are respectively obtained by using any one of the above screening processing methods, and the ink dot uniformity is relatively good. Then, inkjet printing is performed based on these several print data, improving the precision of the printed image.

[0063] Before specifically describing the screening process of the image to be printed to obtain a number of uniform print data according to single-channel precision or the print precision per scan, it is first necessary to explain that the original print precision includes the horizontal print precision and the vertical print precision, which are respectively denoted as the original horizontal print precision and the original vertical print precision. Obtain the original print precision and the number of print passes (or scan times) of the image to be printed, and calculate the actual print precision per scan according to the original print precision and the number of scan times, which is denoted as the single-pass print precision. Similarly, the print precision per scan (single pass) also includes the horizontal print precision and the vertical print precision, which are respectively denoted as the single-pass horizontal print precision and the single-pass vertical print precision.

[0064] In some embodiments, the screening process of the image to be printed according to the original print precision, the number of scan times, and the single-channel precision to obtain a number of print data includes:

[0065] Split the image to be printed into J pieces of image data according to the single-channel precision and the number of scan times, where the single-channel precision is the precision of a column of nozzles in the print head, J is the product of the number of scan times and the number of channels, and J is a natural number greater than or equal to 2;

[0066] Perform screening processes on the J pieces of image data respectively to obtain J pieces of print data.

[0067] The single-channel precision here refers to the longitudinal printing precision that each channel (a column of nozzles) in the print head can achieve. As shown in Fig. 3a, the print head 1 is composed of two channels (two columns of nozzles) with a precision of 300 dpi interleaved (the single-channel precision or the precision of each column of nozzles is 300 dpi). When the two single channels spray the same color ink simultaneously during a single scan, the printing precision (print head precision) of the print head 1 can reach 600 dpi. Then, a single longitudinal printing precision of 600 dpi can be achieved during each scan. Assuming the single transverse printing precision is 600 dpi, then the single printing precision is 600 dpi × 600 dpi, and the single-channel printing precision is 600 dpi × 300 dpi. In this embodiment, the image to be printed is screened according to the single-channel precision to obtain several pieces of print data, and then these several pieces of print data are distributed to the corresponding channels for printing. Exemplarily, assuming the original printing precision of the image to be printed is 1200 dpi × 600 dpi and it is printed in 2 Passes, the single printing precision is 600 dpi × 600 dpi, where the single longitudinal printing precision of 600 dpi is formed by the interpolation printing of two channels with a single-channel precision of 300 dpi. Further, one single printing precision is split into two single-channel printing precisions of 600 dpi × 300 dpi. According to this single-channel printing precision of 600 dpi × 300 dpi, the image to be printed is split into 4 pieces of image data, and then these 4 pieces of image data are screened respectively. Among them, the screening methods for these 4 pieces of image data can be the same or different, and can be any one of the above frequency modulation screening, amplitude modulation screening, 1Bit screening, 2bit screening, three-segment screening, and hybrid screening. The 4 pieces of print data obtained after screening are distributed to the corresponding channels for inkjet printing to obtain the final printed image.

[0068] In some other embodiments, to increase the printing width, several print heads with the same precision are arranged longitudinally to form a print head group. Such as Figure 3bThe following is a schematic diagram of the nozzle group 2, which includes nozzles 21-28. Among them, nozzles 21-24 are longitudinally spliced and arranged in a column, and nozzles 25-28 are longitudinally spliced and arranged in a column. In each scan, nozzles 21-24 are regarded as a virtual nozzle 3, and nozzles 25-28 are regarded as a virtual nozzle 4 to eject ink for printing an image. At this time, the virtual nozzles 3 and 4 are respectively equivalent to two single channels in the nozzle group, and the single-channel accuracy is equal to the accuracy of nozzle 21 (or any one of nozzles 22-28). When printing the image to be printed, similarly, the image to be printed is split into several pieces of image data according to the number of scans, and then the image data is screened according to the single-channel accuracy to obtain several pieces of printing data, and these several pieces of printing data are distributed to the corresponding channels (virtual nozzles 3, 4) for printing. It should be noted that the number of nozzles longitudinally spliced and arranged in the nozzle group 2 or the number of virtual nozzles arranged horizontally can be set according to the actual situation, such as including 16 nozzles arranged in 4 rows and 4 columns, etc. The above numbers are only examples given to clearly disclose the technical principle and do not limit the present invention. Any reasonable setting method is included in the scope of the present invention.

[0069] In some embodiments, the screening the image to be printed according to the original printing accuracy, the number of scans and the single-channel accuracy to obtain several pieces of printing data includes:

[0070] Obtaining the printing accuracy of each scan according to the original printing accuracy and the number of scans, denoted as the single-scan printing accuracy, and the single-channel accuracy is the longitudinal accuracy of the single-scan printing accuracy;

[0071] Splitting the image to be printed into N pieces of image data according to the single-scan printing accuracy and the number of scans, where N is equal to the number of scans, and N is a natural number greater than or equal to 2;

[0072] Performing screening on the N pieces of image data respectively to obtain N pieces of printing data.

[0073] Exemplarily, using such as Figure 4The shown nozzle group 5 (formed by combining 4 nozzles 1) performs scanning and printing. At this time, two single channels in the nozzle 1 spray different color inks respectively. In each scan, the longitudinal printing precision of each channel of C, M, Y, and K can reach 600 dpi for this nozzle group 5. Assuming the single-pass horizontal printing precision is 600 dpi, then the single-pass printing precision of scanning and printing using this nozzle group is 600 dpi×600 dpi. At this time, the image to be printed is screened according to the single-pass printing precision to obtain several pieces of printing data, and then these several pieces of printing data are distributed to the corresponding channels for printing. Exemplarily, assuming the original printing precision of the image to be printed is 1200 dpi×600 dpi, using this nozzle group requires 2-Pass printing, and the single-pass printing precision is 600 dpi×600 dpi. According to this single-pass printing precision and the number of scans 2, the image to be printed is split into 2 pieces of image data, and these 2 pieces of image data are screened respectively. Among them, the screening methods for these 2 pieces of image data can be the same or different, and can be any one of the above frequency modulation screening, amplitude modulation screening, 1Bit screening, 2bit screening, three-segment screening, and hybrid screening. The 4 pieces of printing data obtained after screening are distributed to the corresponding channels for inkjet printing to obtain the final printed image.

[0074] In some embodiments, as Figure 4 The shown nozzle group is composed of 4 nozzles 1 arranged horizontally. After splitting the image to be printed into several pieces of image data according to the single-pass printing precision and the number of scans, further, each piece of image data among these several pieces of image data is split again according to the number of nozzles in the horizontally arranged nozzle group to obtain several sub-image data, and these sub-image data are screened respectively to obtain corresponding sub-printing data. These sub-printing data are distributed to the corresponding nozzles during each scan for inkjet printing respectively, or these sub-printing data are combined into corresponding single-scan printing data and distributed to each Pass for printing. Exemplarily, assuming the original printing precision of the image to be printed is 1200 dpi×600 dpi, using this nozzle group requires 2-Pass printing, and the single-pass printing precision is 600 dpi×600 dpi. According to this single-pass printing precision and the number of scans 2, the image to be printed is split into 2 pieces of image data. Since these 2 pieces of image data are respectively inkjet printed by 4 horizontally arranged nozzles, further, these 2 pieces of image data are divided again according to the number of horizontally arranged nozzles (each piece of image data is divided into 4 sub-image data) to obtain 8 sub-image data, and these 8 sub-image data are combined into 2 pieces of image data (each piece of image data corresponds to 1-Pass scan) and distributed to the corresponding 4 nozzles in two scans for printing.

[0075] The number of general scanning times is determined by four printing precisions: the original horizontal printing precision, the original vertical printing precision, the single - time horizontal printing precision, and the single - time vertical printing precision. Denote the original horizontal printing precision and the original vertical printing precision as M and N respectively, and denote the single - time horizontal printing precision and the single - time vertical printing precision as m and n respectively. Then the scanning times P=(M / m)×(N / n).

[0076] Exemplarily, assume that the original printing precision of the image to be printed is 600dpi×800dpi (where the original horizontal printing precision is 600dpi and the original vertical printing precision is 800dpi), and the nozzle precision is 400dpi (i.e., the single - time vertical printing precision, which is determined by the number of nozzles per inch in the nozzle). If the nozzle scans once along the main scanning direction (single - time) and the printing precision is 600dpi (i.e., the single - time horizontal printing precision is 600dpi, and the single - time horizontal printing precision is determined by the firing frequency of the nozzle. The higher the firing frequency, the greater the single - time horizontal printing precision. However, there is a maximum value for the firing frequency of the nozzle, so the maximum value of the single - time horizontal printing precision is determined by the maximum value of the nozzle firing frequency), then the scanning times P required to print this image to be printed is P=(600dpi / 600dpi)×(800dpi / 400dpi)=2, that is, 2 Pass. If the nozzle scans once along the main scanning direction and the printing precision is 300dpi (i.e., the single - time horizontal printing precision is 300dpi), then P=(600dpi / 300dpi)×(800dpi / 400dpi)=4, that is, 4 Pass. Among them, 2 Pass is required to achieve the original horizontal printing precision, and 2 Pass is required to achieve the original vertical printing precision. Denote the number of Pass required to achieve the original horizontal printing precision as the horizontal printing times, and denote the number of Pass required to achieve the original vertical printing precision as the vertical printing times. Therefore, the scanning times is equal to the product of the horizontal scanning times and the vertical scanning times.

[0077] In addition, it should be noted that when printing the same image to be printed, with different printing modes, the N pieces of image data split and processed according to the number of scans N are different. In some embodiments, the image to be printed is printed in the dot-insertion printing mode. The pixel positions of the first Pass inkjet printing are all ①, the pixel positions of the second Pass inkjet printing are all ②, the pixel positions of the third Pass inkjet printing are all ③, and the pixel positions of the fourth Pass inkjet printing are all ④. When splitting the image to be printed according to the number of scans 4, the image data of the first Pass are all the pixels corresponding to the pixel position ①, the image data of the second Pass are all the pixel data corresponding to the pixel position ②, the image data of the third Pass are all the pixels corresponding to the pixel position ③, and the image data of the fourth Pass are all the pixels corresponding to the pixel position ④. These image data are screened respectively according to the single-pass printing accuracy to obtain 4 different pieces of printing data.

[0078] In some other embodiments, the inkjet printing of the image to be printed is performed in the fusion mode. At the beginning of printing, the first Pass inkjet prints the pixel position ①, the second Pass inkjet prints the pixel positions ① and ②, the third Pass inkjet prints the pixel positions ①, ②, and ③, and the fourth Pass inkjet prints the pixel positions ①, ②, ③, and ④. In each subsequent Pass inkjet printing, the pixel positions are all ①, ②, ③, and ④ (the regions where the pixel positions ①, ②, ③, and ④ are located in each Pass are different). Therefore, when splitting the image to be printed according to the number of scans, the obtained image data are the pixels corresponding to the pixel positions ①, ②, ③, and ④ in different regions. Then, these image data are screened respectively according to the single-pass printing accuracy to obtain 4 different pieces of printing data.

[0079] In some embodiments, since the nozzle ignition frequency is variable, when printing different images to be printed, the single-pass horizontal printing accuracy and the number of scans are variable. And the number of pieces of printing data obtained by screening the image to be printed in this embodiment depends on the single-pass printing accuracy. The smaller the single-pass printing accuracy, the more pieces of printing data are obtained. Therefore, by adjusting the single-pass printing accuracy and the number of scans, the corresponding N pieces of printing data can be obtained. Since the N pieces of printing data are processed using different or the same screening algorithms, the ink dot uniformity is relatively good, making the accuracy of the finally printed image better.

[0080] In some embodiments, obtaining the printing accuracy of each scan according to the original printing accuracy and the number of scans includes:

[0081] Setting the single-pass horizontal printing accuracy to be equal to the original horizontal printing accuracy;

[0082] Obtaining the longitudinal scan number according to the number of scans;

[0083] Divide the original vertical printing precision into a plurality of single - pass vertical printing precisions according to the number of vertical scans, and the sum of the single - pass vertical printing precisions is equal to the original vertical printing precision.

[0084] In this embodiment, the single - pass horizontal printing precision is set to be equal to the original horizontal printing precision, while the single - pass vertical printing precision divides the original vertical printing precision into a plurality of single - pass vertical printing precisions according to the number of vertical scans. These single - pass vertical printing precisions can be the same or different. Exemplarily, if the original printing precision of the image to be printed is 360 dpi×1800 dpi, and the printing precision per pass is 360 dpi×600 dpi, the printing data is printed in 3 Passes (the number of horizontal scans is 1, and the number of vertical scans is 3). In this embodiment, the single - pass horizontal printing precision is set to be equal to the original horizontal printing precision, that is, the horizontal printing precision of the original printing precision remains unchanged, and it is also printed in 3 Passes. However, the vertical printing precision of each Pass can be divided into different or the same printing precisions according to the actual situation. In an example, the single - pass vertical printing precision of each Pass is the same, that is, the original vertical printing precision 1800 dpi is divided by the number of vertical scans 3, which is equal to 600 dpi. Thus, the single - pass printing precision of each Pass is: 360 dpi×600 dpi. The halftoning process is performed on the image to be printed according to this single - pass printing precision to obtain 3 pieces of printing data. Each piece of printing data corresponds to one Pass of printing. The 3 pieces of printing data are sent to the corresponding nozzles for direct inkjet printing, thereby obtaining the printed image. In another example, the vertical printing precision of at least one of the Passes is different. For example, the vertical printing precision of the first Pass is 900 dpi, the vertical printing precision of the second Pass is 300 dpi, and the vertical printing precision of the third Pass is 300 dpi. Thus, the single - pass printing precisions of the first Pass, the second Pass, and the third Pass are 360 dpi×900 dpi, 360 dpi×300 dpi, and 360 dpi×300 dpi respectively. The halftoning process is performed on the image to be printed according to these three single - pass printing precisions to obtain 3 pieces of printing data. The printing data with a printing precision of 360 dpi×900 dpi corresponds to the first Pass of printing, the printing data with a printing precision of 360 dpi×300 dpi corresponds to the second Pass of printing, and the printing data with a printing precision of 360 dpi×300 dpi corresponds to the third Pass of printing. The 3 pieces of printing data are sent to the corresponding nozzles for direct inkjet printing, thereby obtaining the printed image.

[0085] In some embodiments, the single - pass horizontal printing precision is set to be different from the original horizontal printing precision, and the single - pass vertical printing precision is set to be different from the original vertical printing precision. Then, obtaining the printing precision for each scan according to the original printing precision and the number of scans includes:

[0086] Obtaining the horizontal scan number and the vertical scan number according to the number of scans;

[0087] Dividing the original horizontal printing precision into several single - pass horizontal printing precisions according to the horizontal scan number, and the sum of the single - pass horizontal printing precisions is equal to the original horizontal printing precision.

[0088] Dividing the original vertical printing precision into several single - pass vertical printing precisions according to the vertical scan number, and the sum of the single - pass vertical printing precisions is equal to the original vertical printing precision.

[0089] Specifically, according to the original printing precision, nozzle precision, ignition frequency, etc. of the image to be printed, the number of scans required to achieve the original printing precision can be obtained. This number of scans is further divided into a horizontal scan number and a vertical scan number. Exemplarily, the original printing precision is 720dpi×1800dpi, and it is completed by 6 - pass printing. The horizontal scan number is 2, and the vertical scan number is 3. The single - pass printing precision for each pass is: 360dpi×600dpi.

[0090] In this embodiment, the image to be printed is also completed by 6 - Pass printing, but the horizontal printing precision and vertical printing precision for each Pass can be divided into different or the same printing precisions according to the actual situation. In one example, the single - pass horizontal printing precision for each Pass is the same, and the single - pass vertical printing precision for each Pass is the same. That is, dividing the original horizontal printing precision of 720dpi by the horizontal scan number 2 equals 360dpi, and dividing the original vertical printing precision of 1800dpi by the vertical scan number 3 equals 600dpi. Thus, the single - pass printing precision for each Pass is: 360dpi×600dpi. Screening the image to be printed according to this single - pass printing precision to obtain 6 pieces of printing data. Each piece of printing data corresponds to one - Pass printing. Sending the 6 pieces of printing data to the corresponding nozzles for direct ink - jet printing, thereby obtaining the printed image.

[0091] In another example, the original horizontal printing precision of 720 dpi can be divided into a first scan horizontal printing precision of 540 dpi and a second scan horizontal printing precision of 180 dpi. For example, the single-pass printing precision from the first Pass to the sixth Pass is 540 dpi×600 dpi, 180 dpi×600 dpi, 540 dpi×600 dpi, 180 dpi×600 dpi, 540 dpi×600 dpi, 180 dpi×600 dpi respectively. The halftoning process is performed on the image to be printed according to these 6 single-pass printing precisions respectively to obtain 6 sets of printing data. The printing data with a precision of 540 dpi×600 dpi corresponds to the first Pass printing, and the printing data with a precision of 180 dpi×600 dpi corresponds to the second Pass printing, and so on. The 6 sets of printing data are sent to the corresponding nozzles for direct inkjet printing, thereby obtaining the printed image.

[0092] In another example, the maximum horizontal scanning of the printhead of the printing device can achieve 1800 dpi at one time. If the original printing precision is 1800 dpi×400 dpi and it is printed in 3 Passes, then it can be set that the printing precision of each Pass is 600 dpi×400 dpi, or the printing precision of the first Pass is 900 dpi×400 dpi, the printing precision of the second Pass is 300 dpi×400 dpi, and the printing precision of the third Pass is 600 dpi×400 dpi. The halftoning process is performed on the image to be printed according to the printing precision of each Pass to obtain 3 sets of printing data. The 3 sets of printing data are sent to the corresponding nozzles for direct inkjet printing, thereby obtaining the printed image.

[0093] In some other embodiments, before sending N sets of printing data to the printhead for inkjet printing, these N sets of printing data can also be merged into a new set of printing data, and then this new set of printing data is sent to the printhead for inkjet printing. The merged new printing data can be split by the print control board and then sent to the corresponding nozzles for printing respectively. Since the N sets of printing data are processed using different dot algorithms, the ink dot uniformity is relatively good. Merging the N sets of printing data into a new set of printing data will also result in better ink dot uniformity compared to the printing data obtained by performing halftoning according to the original printing precision, thereby improving the final image precision and the printing quality will also be better.

[0094] In summary, in the inkjet printing method according to the embodiment of the present invention, screening processing is performed on the to-be-printed image according to the number of scans of the to-be-printed image and the original printing accuracy and / or the single-channel accuracy to obtain a plurality of pieces of printing data; since the plurality of pieces of printing data are obtained by performing screening processing independently, compared with each Pass printing data split after obtaining the original printing data by performing overall screening processing on the to-be-printed image, the ink dot uniformity is better, and inkjet printing according to the plurality of pieces of printing data can improve the accuracy of the printed image, thereby improving the printing effect and quality of the image.

[0095] Embodiment 2

[0096] Based on the above Embodiment 1, an inkjet printing method based on the concentration relationship curve of image components is provided in an embodiment of the present invention. This method is applicable to a reciprocating scanning inkjet printer, and the printer includes at least one print head, and the print head includes at least one column of nozzles for ink jet printing.

[0097] Please refer to Figure 5 , and the method specifically includes the following steps:

[0098] S1: Obtain the number of scans N required to complete the printing of a unit area of the to-be-printed image, where N is a natural number greater than or equal to 2;

[0099] S2: Obtain N image components of the to-be-printed image according to the number of scans N;

[0100] S3: Obtain the corresponding concentration relationship curve for each of the image components, where the concentration relationship curve is a curve of the relationship between the concentration of the image component and the concentration of the to-be-printed image;

[0101] S4: Perform screening processing on the N image components respectively according to the corresponding concentration relationship curves to obtain N pieces of printing data;

[0102] S5: Inkjet print the to-be-printed image according to the N pieces of printing data.

[0103] When the image precision of the image to be printed is higher than the precision of the print head, multi-PASS printing is required to achieve the image precision of the image to be printed. In the prior art, before printing, the image to be printed needs to be screened or halftoned. Here, the image to be printed is a continuous-tone image. After screening, the print data recognizable by the printer is obtained. The image precision of the image to be printed is called the original print precision. After screening the image to be printed according to the original print precision, the print data of the image to be printed is obtained. The printer divides the print data of the image to be printed into several PASS print data according to the print head precision and the firing frequency, and distributes each PASS print data to the corresponding print head for each PASS printing. In order to improve the uniformity of the image, in the embodiment, instead of obtaining one print data by screening according to the original print precision, the image to be printed is first split into N pieces of image data (N image components) according to the number of scans N, and then the image components are screened according to the print precision at each scan to obtain N pieces of print data. The print precision at each scan is also recorded as the single-pass print precision, and the single-pass print precision is the actual print precision per PASS calculated according to the original print precision and the number of print PASSes. The N pieces of print data are processed using the same or different screening algorithms, and the ink dot uniformity is relatively good. Inkjet printing based on the N pieces of print data can improve the uniformity of the printed image. However, if there are light-concentration areas in the image to be printed, when printing according to the print data of each component after the above processing (each image component starts to print ink dots gradually from the point where the concentration is 0), white spots are likely to appear in the light-concentration areas, affecting the image printing quality. Therefore, in the embodiment of the present invention, after obtaining the N image components, different screening is performed on each image component according to different concentration relationship curves, and ink dots are printed from different starting concentrations for different image components, so that while the ink dot distribution is more uniform when printing the image to be printed, the problem of white spots in the light-concentration areas is solved.

[0104] Specifically, before printing, the image to be printed is first divided into N image components according to the number of scans N. Exemplarily, the image to be printed shown in Fig. 1a is completed by 4PASS printing. The image to be printed is printed in an interpolation printing mode, that is, the pixel positions of the first PASS inkjet printing are all ①, the pixel positions of the second PASS inkjet printing are all ②, the pixel positions of the third PASS inkjet printing are all ③, and the pixel positions of the fourth PASS inkjet printing are all ④. When the image to be printed is split according to the number of scans 4, the image data of the first PASS (the first image component) are all the pixels corresponding to the pixel position ①, the image data of the second PASS (the second image component) are all the pixels corresponding to the pixel position ②, the image data of the third PASS (the third image component) are all the pixels corresponding to the pixel position ③, and the image data of the fourth PASS (the fourth image component) are all the pixels corresponding to the pixel position ④. The 4 obtained image components are as Figure 6 shown.

[0105] In some other embodiments, different printing modes are used for printing, and the 4 obtained image component data are not the same as those Figure 4 shown. Exemplarily, the inkjet printing of the image to be printed is performed in a fusion mode. At the beginning of printing, the first PASS inkjet prints the pixel position ①, the second PASS inkjet prints the pixel positions ① and ②, the third PASS inkjet prints the pixel positions ①, ②, and ③, and the third PASS inkjet prints the pixel positions ①, ②, ③, and ④. In each subsequent PASS inkjet printing, they are all the pixel positions ①, ②, ③, and ④ (the regions where the pixel positions ①, ②, ③, and ④ are located in each PASS are different). Therefore, when the image to be printed is split according to the number of scans, the 4 obtained image components are the pixels corresponding to the pixel positions ①, ②, ③, and ④ in different regions. Therefore, the image components obtained by splitting the image to be printed as described above depend on the actual printing mode. The above examples are only for illustration and are not used to limit the scope of the present invention.

[0106] After obtaining N image components, the corresponding concentration relationship curves of the N image components are respectively obtained. Here, the concentration relationship curve is the relationship curve between the image component concentration and the image concentration to be printed. Here, the image component concentration refers to the printing concentration corresponding to the image component; the image concentration to be printed refers to the printing concentration corresponding to the image to be printed.

[0107] In one embodiment, the obtaining the corresponding concentration relationship curve of each of the image components includes:

[0108] Establish a two-dimensional coordinate system with the image concentration to be printed as the horizontal axis and the image component concentration as the vertical axis;

[0109] Obtain the preset starting point and the preset reference point of the concentration relationship curve of each of the image components;

[0110] Obtain the concentration relationship curve of each of the image components based on the preset starting point and the preset reference point.

[0111] Specifically, obtain the concentration relationship curve between the image component concentration and the image to be printed concentration according to the corresponding relationship between the concentration of each image component and the concentration of the image to be printed. Take the concentration of the image to be printed as the horizontal axis and the concentration of the image component as the vertical axis to establish a two-dimensional coordinate system. Among them, the value ranges of the concentration of the image to be printed and the concentration of the image component are both between 0 and 100%. After establishing the coordinate system, set a preset starting point for the concentration relationship curve corresponding to each image component, denoted as the first preset starting point, the second preset starting point, ……, the Nth preset starting point respectively; set a preset reference point for the concentration relationship curve corresponding to each image component, denoted as the first preset reference point, the second preset reference point, ……, the Nth preset reference point respectively. Obtain N concentration relationship curves according to the above N preset starting points and N preset reference points, denoted as the first concentration relationship curve, the second concentration relationship curve, ……, the Nth concentration relationship curve respectively.

[0112] In some embodiments, the coordinates of the first preset starting point A1, the second preset starting point A2, ……, the Nth preset starting point AN are respectively (T 1 , 0), (T 2 , 0), …… (T N , 0), where the abscissa values T 1 , T 2 , ……, T N are obtained through multiple repeated test prints, and T 1 , T 2 , ……, T N are real numbers. The coordinates of the N preset reference points are all (100%, 100%). In some other embodiments, the coordinates of the N preset reference points may also be partially the same or completely different. The N preset reference points are also obtained through multiple repeated test prints or set by the user according to the actual application situation, and are not limited here.

[0113] Exemplarily, as Figure 7a shown, the coordinates of the first preset starting point A1, the second preset starting point A2, ……, the Nth preset starting point AN are respectively (T 1 , 0), (T 2 , 0), …… (T N , 0), and the coordinates of the first preset reference point B1, the second preset reference point B2, ……, the Nth preset reference point BN can be set to be different according to the actual situation. In this example, the coordinates of the first preset reference point B1, the second preset reference point B2, ……, the Nth preset reference point BN are respectively: (100%, 100%), (100%, S2 ), ……, (100%, S N ), where S 2 , ……, S N is a real number. In other embodiments, the preset reference point can be a point at any position outside the preset starting point in the coordinate system. For example, the coordinates of the first preset reference point are (50%, 50%). Connect the first preset starting point and the first preset reference point, the second preset starting point and the second preset reference point, ……, the Nth preset starting point and the Nth preset reference point with straight lines to obtain N concentration relationship curves C1, C2, ……, CN.

[0114] In one example, as Figure 7b shown, the coordinates of the first preset starting point, the second preset starting point, ……, the Nth preset starting point are respectively (T 1 , 0), (T 2 , 0), ……, (T N , 0), and the first preset reference point, the second preset reference point, ……, the Nth preset reference point are set to the same coordinates (100%, 100%). Fit (such as cubic spline fitting) according to the first preset starting point and the first preset reference point to obtain the first concentration relationship curve Q1, fit according to the second preset starting point and the second preset reference point to obtain the second concentration relationship curve Q2, ……, fit according to the Nth preset starting point and the Nth preset reference point to obtain the Nth concentration relationship curve QN.

[0115] In another example, as Figure 7c shown, after obtaining N concentration relationship curves C1, C2, ……, CN as shown in Figure 7a , it is also possible to perform smoothing processing on some specified concentration relationship curves, such as the part of the curve near the starting point or within a preset range (such as within the range where the horizontal axis value in the second concentration relationship curve C2 is T2 + 5%) of the second concentration relationship curve C2 to obtain the smoothed curve C2', so that the starting ink position of the image component transitions smoothly and the image printing quality is improved.

[0116] In some embodiments, the concentration relationship curve can also be obtained by intercepting the monotonically increasing part of the corresponding curves of parabolic functions, trigonometric functions (such as sine functions, tangent functions), etc. Exemplarily, it can be known that the function of the parabola is expressed as: y = ax 2 + bx + c. As Figure 8 shown, intercept the curve of the monotonically rising (increasing) part of the parabola P. Define the numerical value of the x-axis as the concentration of the image to be printed, and the numerical value of the y-axis as the concentration of the image component, and the x value range is [0, 100%]. In this example, let a = 1, b = c = 0, so that when x = 100%, y = 100%. The function representation of the obtained first concentration relationship curve P1 is: y = x2 , and \(x\in[0,100\%]\). It should be noted that the values of \(a\), \(b\), and \(c\) can be set according to the actual situation or obtained through multiple repeated tests and printings to get better values. The values in the above examples are only for illustration and are not used to limit the present invention. Similarly, a second concentration relationship curve \(P2: y = d(x - T 2 ) 2 +e(x - T 2 )+f\) is obtained using a parabola function, where \(d\), \(e\), and \(f\) can be set according to the actual situation or obtained through multiple repeated tests and printings to get better values, so that the printing result obtained after screening according to this second concentration relationship curve meets the user's requirements; similarly, an \(N\)th concentration relationship curve \(PN: y = g(x - T N ) 2 +h(x - T N )+k\) is obtained using a parabola, where \(g\), \(h\), and \(k\) can be set according to the actual situation or obtained through multiple repeated tests and printings to get better values, so that the printing result obtained after screening according to this \(N\)th concentration relationship curve meets the user's requirements.

[0117] In some embodiments, a preset concentration threshold \(X\) is set such that \(T 1 , \(T 2 , \(\cdots\), \(T N \) are all less than or equal to \(X\). Preferably, \(X = 20\%\).

[0118] In some embodiments, the values of \(T 1 , \(T 2 , \(\cdots\), \(T N \) are different from each other and satisfy: \(T 1 = 0\) and \(T 1 \lt T 2 \lt \cdots \lt T N \leq X\). Exemplarily, \(N = 4\); \(X = 20\%\), \(T 2 = 8\%\), \(T 3 = 10\%\), \(T 4 = 12\%\). Exemplarily, \(N = 4\); \(X = 20\%\), \(T 2 = 15\%\), \(T 3 = 17\%\), \(T 4 = 18\%\).

[0119] In some embodiments, the values of \(T 1 , \(T 2 , \(\cdots\), \(T N \) are partially the same and satisfy: \(T 1 = 0\) and \(T 1 \lt T 2 = T 3 = \cdots = T N \leq X\). Exemplarily, \(N = 4\); \(X = 20\%\), \(T 2= 10%, T 3 = 10%, T 4 = 10%.

[0120] In some embodiments, T 1 , T 2 , ……, T N has the same value and satisfies: T 1 = T 2 = …… = T N-1 = 0 and T N-1 < T N ≤ X. Exemplarily, N = 4; X = 20%, T 1 = 0, T 2 = 0, T 3 = 0, T 4 = 10%.

[0121] In some embodiments, T 1 , T 2 , ……, T N has different values and satisfies: T 1 < T 2 < …… < T N ≤ X and T i – T i-1 = T i-1 - T i-2 , i = 2, ……, N. At this time, each starting printing concentration increases uniformly. Exemplarily, N = 4; X = 20%, T 1 = 0, T 2 = 4%, T 3 = 8%, T 4 = 12%.

[0122] In some embodiments, T 1 , T 2 , ……, T N has different values and satisfies T 1 < T 2 < …… < T N ≤ X. Exemplarily, N = 4; X = 20%, T 1 = 1%, T 2 = 6%, T 3 = 10%, T 4 = 12%.

[0123] In some embodiments, T 1 , T 2 , ……, T N not only satisfies T 1 < T 2 < …… < T N≤X outside, some values increase uniformly. Exemplarily, N = 4; X = 20%, T 1 = 0%, T 2 = 4%, T 3 = 8%, T 4 = 20%.

[0124] It should be noted that X, T 1 , T 2 , T 3 ...T N are not necessarily set according to the rules shown in the above embodiments, but are specifically set according to the actual application situation. The above examples are only for illustration, and reasonable setting methods are all included in the scope of the present invention. Then, according to the first concentration relationship curve, the second concentration relationship curve,..., the Nth concentration relationship curve, screening processing is performed on the first image component, the second image component,..., the Nth image component to be processed to obtain N pieces of printing data. The screening processing methods here include using frequency modulation screening, amplitude modulation screening, 1Bit screening, 2bit screening, three-segment screening, hybrid screening, etc. Among them, 1bit screening means that the printing data obtained after screening the image to be printed only includes "1" or "0", where "1" represents ink output and "0" represents no ink output; 2bit screening means that the printing data obtained after screening the image to be printed includes "00", "01", "10" and "11", where "00" represents no ink output, "01" represents small dots output, "10" represents medium dots output, and "11" represents large dots output. Three-segment screening means that when the concentration n of the image ≤ X1, the printing data is all expressed by blank dots and small dots, and the concentration of small dots changes gradually from 0 to 100%, when X1 < n ≤ X2, it is all expressed by small dots and medium dots, and the concentration of medium dots changes gradually from 0 to 100%, when n > X2, it is all expressed by medium dots and large dots, and the concentration of large dots changes from 0 to 100%. Hybrid screening means that when the concentration n of the image reaches X1, it is only expressed by blank dots and small dots, and after reaching X1, medium dots are gradually added and expressed by blank dots, small dots and medium dots, and when the concentration n reaches X2, large dots are gradually added and expressed by blank dots, small dots, medium dots and large dots. The values of X1 and X2 can be set according to the actual situation.

[0125] After screening the N image components to be processed according to the corresponding concentration relationship curves, N pieces of printing data are obtained, and the N pieces of printing data are distributed to the corresponding PASS for printing. Using the concentration relationship curve to screen the N image components adjusts the starting ink output positions of different image components, and the dot pattern of the image to be printed obtained has evenly distributed dots even in the light-concentration area, as Figure 9 shown Figure 9The upper figure in the middle is the dot distribution diagram of the lighter concentration area obtained after screening using the concentration relationship curve, and the lower figure is Figure 1b the dot distribution diagram of the lighter concentration area shown in Figure 1b . By comparison, compared with the relatively disordered dot distribution in the lighter concentration area shown in

[0126] the dot distribution diagram of the lighter concentration area obtained after screening using the concentration relationship curve is more uniform. Correspondingly, when inkjet printing, the distribution of ink dots is more uniform, which can improve the image accuracy while solving the problem of white gaps, thereby improving the image printing quality.

[0127] Embodiment 3

[0128] Please refer to Figure 10 , an inkjet printing device 200 based on the concentration relationship curve of image components is provided in an embodiment of the present invention. The device 200 includes:

[0129] A scanning times acquisition module, configured to acquire the scanning times N required to complete printing of a unit area of the image to be printed, where N is a natural number greater than or equal to 2;

[0130] An image component acquisition module, configured to acquire N image components of the image to be printed according to the scanning times N;

[0131] A concentration relationship curve acquisition module, configured to acquire the corresponding concentration relationship curve for each of the image components, where the concentration relationship curve is a relationship curve between the concentration of the image component and the concentration of the image to be printed;

[0132] A screening module, configured to perform screening processing on the N image components respectively according to the corresponding concentration relationship curves to obtain N pieces of printing data;

[0133] A printing module, configured to inkjet print the image to be printed according to the N pieces of printing data.

[0134] Preferably, the concentration relationship curve acquisition module includes:

[0135] A coordinate setting unit for establishing a two-dimensional coordinate system with the concentration of the image to be printed as the horizontal axis and the concentration of the image component as the vertical axis;

[0136] A key point acquisition unit for acquiring a preset starting point and a preset reference point of the concentration relationship curve of each of the image components;

[0137] A curve acquisition unit for acquiring the concentration relationship curve of each of the image components according to the preset starting point and the preset reference point.

[0138] Preferably, the key point acquisition unit includes:

[0139] A starting point setting unit for respectively setting the preset starting points of the concentration relationship curves of the N image components as: (T 1 , 0), (T 2 , 0),..., (T N , 0), where the values of T1, T2,..., T N are one of the following:

[0140] T 1 = 0 and T 1 < T 2 <... < T N ≤ X;

[0141] T 1 = 0 and T 1 < T 2 = T 3 =... = T N ≤ X;

[0142] T 1 = T 2 =... = T N-1 = 0 and T N-1 < T N ≤ X;

[0143] T 1 < T 2 <... < T N ≤ X and T i – T i-1 = T i-1 - T i-2 , where i = 2,..., N;

[0144] where X is a preset concentration threshold.

[0145] Preferably, the concentration relationship curve acquisition module further includes:

[0146] A smoothing unit for smoothing the curve part within the preset range of the starting point of the concentration relationship curve.

[0147] Preferably, in the screening module, the screening process includes any one of frequency modulation screening, amplitude modulation screening, 1Bit screening, 2bit screening, three-stage screening, and hybrid screening.

[0148] Preferably, in the screening module, the screening methods of several copies of the print data are the same or different.

[0149] In summary, the inkjet printing device based on the image component concentration relationship curve provided by the embodiment of the present invention obtains the number of scans N required for printing a unit area of the to-be-printed image, obtains N image components of the to-be-printed image according to the number of scans N, and performs screening processing on the N image components respectively according to the corresponding concentration relationship curves to obtain N copies of print data. Finally, the to-be-printed image is inkjet printed according to the N copies of print data, making the ink dot distribution more uniform, improving the image accuracy while solving the problem of white showing in the areas with relatively light concentration, and improving the image printing quality.

[0150] Embodiment 4

[0151] In addition, the inkjet printing method based on the image component concentration relationship curve in the embodiment of the present invention can be implemented by an inkjet printing device based on the image component concentration relationship curve. Figure 11 The hardware structure diagram of the inkjet printing device based on the image component concentration relationship curve provided by the embodiment of the present invention is shown.

[0152] The inkjet printing device based on the image component concentration relationship curve may include a processor 301 and a memory 302 storing computer program instructions.

[0153] Specifically, the above-mentioned processor 301 may include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present invention.

[0154] The memory 302 may include a mass storage for data or instructions. By way of example and not limitation, the memory 302 may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive, or a combination of two or more of these. Where appropriate, the memory 302 may include removable or non-removable (or fixed) media. Where appropriate, the memory 302 may be internal or external to the data processing device. In a particular embodiment, the memory 302 is a non-volatile solid-state memory. In a particular embodiment, the memory 302 includes a read-only memory (ROM). Where appropriate, the ROM may be a mask-programmed ROM, a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), an electrically rewritable ROM (EAROM), or a flash memory, or a combination of two or more of these.

[0155] The processor 301 reads and executes the computer program instructions stored in the memory 302 to implement any one of the inkjet printing methods based on the image component concentration relationship curve in the above embodiments.

[0156] In one example, the inkjet printing device based on the image component concentration relationship curve may further include a communication interface 303 and a bus 310. Among them, as Figure 11 shown, the processor 301, the memory 302, and the communication interface 303 are connected through the bus 310 to complete communication with each other.

[0157] The communication interface 303 is mainly used to implement communication between the modules, devices, units, and / or devices in the embodiments of the present invention.

[0158] The bus 310 includes hardware, software, or both, and couples the components of the inkjet printing device based on the image component concentration relationship curve together. By way of example and not limitation, the bus 310 may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a HyperTransport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an InfiniBand interconnect, a Low Pin Count (LPC) bus, a memory bus, a MicroChannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or other suitable buses, or a combination of two or more of these. In suitable cases, the bus 310 may include one or more buses. Although the embodiments of the present invention describe and illustrate specific buses, the present invention contemplates any suitable bus or interconnect.

[0159] Embodiment Four

[0160] In addition, in combination with the inkjet printing method based on the image component concentration relationship curve in the above embodiments, the embodiments of the present invention can be implemented by providing a computer-readable storage medium. Computer program instructions are stored on the computer-readable storage medium; when the computer program instructions are executed by the processor 301, any one of the inkjet printing methods based on the image component concentration relationship curve in the above embodiments is implemented.

[0161] In summary, the inkjet printing method, apparatus, and device based on the image component concentration relationship curve provided by the embodiments of the present invention obtain the number of scans N required to complete the printing of a unit area of the image to be printed, obtain N image components of the image to be printed according to the number of scans N, perform screening processing on the N image components respectively according to the corresponding concentration relationship curves to obtain N pieces of print data, and finally inkjet print the image to be printed according to the N pieces of print data, making the ink dot distribution more uniform, improving the image accuracy while solving the problem of white showing in areas with relatively light concentration, and improving the image printing quality.

[0162] It should be clear that the present invention is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, the detailed description of known methods is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications, and additions, or change the order between steps after understanding the spirit of the present invention.

[0163] The functional blocks shown in the above-described structural block diagrams can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application-specific integrated circuit (ASIC), appropriate firmware, a plug-in, a functional card, and so on. When implemented in software, the elements of the present invention are programs or code segments for performing the required tasks. The program or code segment can be stored in a machine-readable medium or transmitted via a data signal carried in a carrier wave over a transmission medium or a communication link. A "machine-readable medium" can include any medium that can store or transmit information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio frequency (RF) links, and so on. The code segment can be downloaded via a computer network such as the Internet, an intranet, and so on.

[0164] It should also be noted that the exemplary embodiments mentioned in the present invention describe some methods or systems based on a series of steps or devices. However, the present invention is not limited to the order of the above steps, that is, the steps can be executed in the order mentioned in the embodiments, can be different from the order in the embodiments, or several steps can be executed simultaneously.

[0165] As described above, the above is only the specific implementation manner of the present invention. Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the above-described systems, modules, and units can refer to the corresponding processes in the foregoing method embodiments and will not be repeated herein. It should be understood that the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. An inkjet printing method based on the concentration relationship curve of image components, characterized in that, the method includes: obtaining the number of scans N required to complete the printing of a unit area of the image to be printed, where N is a natural number greater than or equal to 2; obtaining N image components of the image to be printed according to the number of scans N; obtaining the corresponding concentration relationship curve for each of the image components, where the concentration relationship curve is a curve representing the relationship between the image component concentration and the concentration of the image to be printed; performing screening processing on the N image components respectively according to the corresponding concentration relationship curves to obtain N pieces of printing data; inkjet printing the image to be printed according to the N pieces of printing data.

2. The inkjet printing method based on the concentration relationship curve of image components according to claim 1, characterized in that, the obtaining of the corresponding concentration relationship curve for each of the image components includes: establishing a two-dimensional coordinate system with the concentration of the image to be printed as the horizontal axis and the image component concentration as the vertical axis; obtaining the preset starting point and preset reference point of the concentration relationship curve for each of the image components; obtaining the concentration relationship curve for each of the image components according to the preset starting point and the preset reference point.

3. The inkjet printing method based on the concentration relationship curve of image components according to claim 2, characterized in that, The preset starting point coordinates of the concentration relationship curves of the N image components are respectively: (T 1 , 0), (T 2 , 0),..., (T N , 0), where the values of T1, T2,..., T N are one of the following: T 1 = 0 and T 1 < T 2 < … < T N ≤ X; T 1 = 0 and T 1 < T 2 = T 3 = …… = T N ≤ X; T 1 = T 2 = …… = T N-1 = 0 and T N-1 < T N ≤ X; T 1 <T 2 <……<T N ≤X and T i –T i-1 =T i-1 -T i-2 where i = 2, ……, N; where X is a preset concentration threshold.

4. The inkjet printing method based on the concentration relationship curve of image components according to claim 2, characterized in that, after obtaining the concentration relationship curve for each of the image components according to the preset starting point and the preset reference point, it further includes: performing smoothing processing on the curve part within the preset range of the starting point of the concentration relationship curve.

5. The inkjet printing method based on the concentration relationship curve of image components according to claim 3, characterized in that, N = 4, X = 20%, T 1 = 0, T 2 = 8%, T 3 = 10%, T 4 = 12%.

6. The inkjet printing method based on the concentration relationship curve of image components according to any one of claims 1-5, characterized in that, the screening processing includes any one of frequency modulation screening, amplitude modulation screening, 1Bit screening, 2bit screening, three-segment screening, and hybrid screening.

7. The inkjet printing method based on the concentration relationship curve of image components according to any one of claims 1-5, characterized in that, the screening methods of several pieces of the printing data are the same or different.

8. An inkjet printing device based on the concentration relationship curve of image components, characterized in that, the device includes: a scan number acquisition module for obtaining the number of scans N required to complete the printing of a unit area of the image to be printed, where N is a natural number greater than or equal to 2; an image component acquisition module for obtaining N image components of the image to be printed according to the number of scans N; a concentration relationship curve acquisition module for obtaining the corresponding concentration relationship curve for each of the image components, where the concentration relationship curve is a curve representing the relationship between the image component concentration and the concentration of the image to be printed; a screening module for performing screening processing on the N image components respectively according to the corresponding concentration relationship curves to obtain N pieces of printing data; a printing module for inkjet printing the image to be printed according to the N pieces of printing data.

9. An inkjet printing device based on an image component concentration relationship curve, characterized in that, comprising: at least one processor, at least one memory, and computer program instructions stored in the memory, which implement the method according to any one of claims 1-7 when the computer program instructions are executed by the processor.

10. A storage medium having computer program instructions stored thereon, characterized in that, the method according to any one of claims 1-7 is implemented when the computer program instructions are executed by a processor.

Images