Double-sided inkjet printing method, device and equipment based on ink amount optimization

Abstract

The application discloses a double-sided inkjet printing method, device and equipment based on ink volume optimization, and relates to the technical field of inkjet printing. The method is based on a driving mechanism to drive a first printing trolley and a second printing trolley to move synchronously towards or reversely at the same printing height, so that the front and back surfaces of a printing medium are printed simultaneously. Compared with the existing double-sided inkjet printing technology, the method does not need to wait for ink drying or perform additional turning operation, can significantly shorten the printing time, improve the printing efficiency, and when the front and back surfaces are printed synchronously, the time and position of ink penetration into the front and back surfaces of the printing medium are close, thereby reducing the tension difference between the front and back surfaces caused by ink penetration in sequence, reducing the influence of the tension difference on the printing effect, and being beneficial to improving the printing quality. In addition, the data processing mode during printing in the method is simple and efficient, and the printing ink volume is optimized, so that the demand of double-sided inkjet printing can be better met, the printing quality and efficiency are improved, and the user satisfaction is improved.

Description

[0001] This application is a divisional application of the invention patent application filed on April 25, 2024, entitled "Double-sided inkjet printing method, apparatus and equipment" with application number 202410502363.9. Technical Field

[0002] This invention relates to the field of inkjet printing technology, and in particular to a method, apparatus and equipment for double-sided inkjet printing based on ink volume optimization. Background Technology

[0003] In digital inkjet printing applications, duplex inkjet printing is a technology that uses inkjet printing on both sides of a printing medium, such as paper, textiles, glass, and acrylic, to form an image. Traditional inkjet printers typically only spray ink on one side of the printing medium, requiring the ink to dry on the other side before printing, which is time-consuming. Furthermore, please refer to the duplex printing method disclosed in patent application publication number "CN109334254A" entitled "Double-sided Printing Method and Double-sided Printing Machine." Existing duplex printing requires a complex fabric winding structure and two scanning mechanisms on the front and back sides. First, the front scanning mechanism (the first printing carriage) is controlled to inkjet print on the front side, and then, with the assistance of the fabric winding roller, the back scanning mechanism (the second printing carriage) can inkjet print on the back side, thus achieving duplex printing. This printing method has the following drawbacks: If one side is printed first and the ink seeps in first, the side that has absorbed the ink will show significant changes in tension and quality, resulting in tension differences between the two sides of the printing medium. This will affect the accuracy of the transmission system or the feeding and unloading system in the front and back sides. Furthermore, since two scanning mechanisms are used, two positioning mechanisms (such as grating rulers) are required to position the printhead for ignition. It is difficult to guarantee the mechanical rigidity and consistency of error between the two positioning mechanisms, which will also lead to errors in double-sided image printing and affect print quality. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a method, apparatus and equipment for double-sided inkjet printing based on ink volume optimization, in order to solve the problems of low efficiency and poor print quality in double-sided inkjet printing in the prior art.

[0005] In a first aspect, embodiments of the present invention provide a duplex inkjet printing method based on ink volume optimization. The method is applied to a duplex inkjet printing device, wherein the duplex inkjet printing device includes a first printing carriage and a second printing carriage, a printing medium is vertically disposed between the first printing carriage and the second printing carriage, and the first printing carriage and the second printing carriage can reciprocate along the main scanning direction under the drive of the same driving mechanism. The first printing carriage is used to eject ink onto the front side of the printing medium to form an image, and the second printing carriage is used to eject ink onto the back side of the printing medium to form an image. The method includes:

[0006] Obtain the image to be printed, and perform rasterization processing on the image to be printed to obtain the first printing data;

[0007] The first printed data is expanded to obtain the second printed data;

[0008] Extract the third and fourth print data from the second print data respectively;

[0009] The fourth printed data is processed to obtain the fifth printed data;

[0010] The third and fifth printing data are sent to the first and second printing carriages respectively, and the first and second printing carriages are driven to move synchronously towards or in opposite directions at the same printing height and spray ink onto the front and back sides of the printing medium to form an image.

[0011] The first printed data consists of dot data. Before expanding the first printed data to obtain the second printed data, the method further includes: obtaining the total ink volume corresponding to the first printed data; determining the preferred values ​​of the ink volume carried by the front and back sides of the printing medium, respectively denoted as the first preferred ink volume and the second preferred ink volume; and adjusting the ink volume value corresponding to the dot data according to the total ink volume and the first preferred ink volume and the second preferred ink volume.

[0012] Preferably, the dot data includes large ink dot data, medium ink dot data, and small ink dot data, and their corresponding ink amounts are respectively denoted as the first ink amount, the second ink amount, and the third ink amount, wherein the first ink amount > the second ink amount > the third ink amount. The adjustment of the ink amount value corresponding to the dot data based on the total ink amount and the first preferred ink amount and the second preferred ink amount includes:

[0013] Determine whether the first difference between the total ink volume and the first preferred ink volume is greater than or equal to a preset threshold and / or whether the second difference between the total ink volume and the second preferred ink volume is greater than or equal to the preset threshold;

[0014] If so, obtain the ink volume adjustment value based on the first difference and / or the second difference;

[0015] Adjust one or more of the first ink volume, the second ink volume, and the third ink volume according to the ink volume adjustment value.

[0016] Preferably, when the materials on both sides of the printing medium are the same, the first preferred ink amount and the second preferred ink amount are the same; when the materials on both sides of the printing medium are different, the first preferred ink amount and the second preferred ink amount are different.

[0017] Preferably, the first print data includes first black channel data, first cyan channel data, first magenta channel data, and first yellow channel data, each with N rows, and the step of expanding the first print data to obtain the second print data includes:

[0018] Copy the first black channel data, first cyan channel data, first magenta channel data, and first yellow channel data of the i-th row of the first printed data respectively to obtain the second black channel data, second cyan channel data, second magenta channel data, and second yellow channel data of the i-th row;

[0019] Insert the second black channel data, second cyan channel data, second magenta channel data, and second yellow channel data of the i-th row between the first black channel data, first cyan channel data, first magenta channel data, and first yellow channel data of the i-th and i+1-th rows to obtain the second print data;

[0020] Where i = 0, 1, 2, ..., N-1, and N is a natural number greater than or equal to 1.

[0021] Preferably, the step of extracting the third and fourth print data from the second print data includes:

[0022] The first black channel data, the first cyan channel data, the first magenta channel data, and the first yellow channel data are extracted sequentially from the second print data according to the row number and used as the third print data;

[0023] The second black channel data, second cyan channel data, second magenta channel data, and second yellow channel data, which correspond one-to-one with the number of rows of the first black channel data, first cyan channel data, first magenta channel data, and first yellow channel data in the third print data, are extracted from the second print data as the fourth print data.

[0024] Preferably, the step of processing the fourth print data to obtain the fifth print data includes:

[0025] The fourth printed data is mirrored to obtain mirrored printed data;

[0026] Determine whether the end of each line of data in the mirrored printed data contains blank data;

[0027] If so, the blank data is placed at the beginning of each line of data to obtain the fifth printed data;

[0028] If not, the mirror print data is the fifth print data.

[0029] Preferably, after processing the fourth print data to obtain the fifth print data, the method further includes:

[0030] The first printing carriage and the second printing carriage are controlled to print the first test image and the second test image on the front and back of the printing medium respectively according to the third printing data and the fifth printing data;

[0031] Obtain the vertical alignment deviation between the first test image and the second test image;

[0032] Based on the vertical alignment deviation, insert or delete several blank data at the beginning of each line of data in the third and / or fifth printed data;

[0033] And / or:

[0034] Obtain the horizontal alignment deviation between the first test image and the second test image;

[0035] Based on the horizontal alignment deviation, insert or delete several lines of blank data in the third and / or fifth printed data.

[0036] Preferably, before sending the third and fifth print data to the first and second print carriages respectively, and driving the first and second print carriages to move synchronously towards each other from both ends of the print medium at the same print height and eject ink onto both sides of the print medium to form an image, the method further includes:

[0037] Obtain the maximum scanning width of the first printing carriage in the main scanning direction, and denote it as the first width;

[0038] Obtain the width of the image to be printed in the main scanning direction, and denote it as the second width;

[0039] The starting printing positions of the first printing carriage and the second printing carriage are obtained based on the first width and the second width.

[0040] Secondly, embodiments of the present invention provide a duplex inkjet printing apparatus based on ink volume optimization. The apparatus is applied to a duplex inkjet printing device, wherein the duplex inkjet printing device includes a first printing carriage and a second printing carriage. A printing medium is vertically disposed between the first printing carriage and the second printing carriage. The first printing carriage and the second printing carriage can reciprocate along the main scanning direction under the drive of the same driving mechanism. The first printing carriage is used to eject ink onto the front side of the printing medium to form an image, and the second printing carriage is used to eject ink onto the back side of the printing medium to form an image. The apparatus includes:

[0041] The data acquisition module is used to acquire the image to be printed and to perform rasterization processing on the image to be printed to obtain the first printing data.

[0042] The data expansion module is used to expand the first printed data to obtain the second printed data;

[0043] The data extraction module is used to extract the third and fourth print data from the second print data, respectively.

[0044] The data processing module is used to process the fourth printed data to obtain the fifth printed data;

[0045] The printing module is used to send the third printing data and the fifth printing data to the first printing carriage and the second printing carriage respectively, drive the first printing carriage and the second printing carriage to move synchronously towards or in opposite directions at the same printing height and spray ink onto the front and back sides of the printing medium to form an image;

[0046] The total ink acquisition module is used to acquire the total ink volume corresponding to the first print data, wherein the first print data is composed of dot data;

[0047] The ink volume is selected to determine the preferred values ​​of the ink volume carried on the front and back sides of the printing medium, respectively, and is denoted as the first preferred ink volume and the second preferred ink volume.

[0048] The adjustment module is used to adjust the ink volume value corresponding to the point data according to the total ink volume, the first preferred ink volume, and the second preferred ink volume.

[0049] Thirdly, embodiments of the present invention provide a duplex inkjet printing device based on ink volume optimization, wherein the duplex inkjet printing device includes a first printing carriage and a second printing carriage, a printing medium is vertically disposed between the first printing carriage and the second printing carriage, the first printing carriage and the second printing carriage can reciprocate along the main scanning direction under the drive of the same driving mechanism, the first printing carriage is used to spray ink onto the front side of the printing medium to form an image, and the second printing carriage is used to spray ink onto the back side of the printing medium to form an image; the duplex inkjet printing device further includes: at least one processor, at least one memory, and computer program instructions stored in the memory, which, when executed by the processor, implement the method of the first aspect of the above embodiments.

[0050] Fourthly, embodiments of the present invention provide a storage medium storing computer program instructions, which, when executed by a processor, implement the method of the first aspect described above.

[0051] In summary, the beneficial effects of the present invention are as follows:

[0052] The present invention provides a duplex inkjet printing method, apparatus, and device based on ink volume optimization. A single drive mechanism drives a first printing carriage and a second printing carriage to move synchronously in opposite directions at the same printing height, enabling simultaneous printing on both sides of the printing medium. Compared to existing duplex inkjet printing technologies, this eliminates the need to wait for ink to dry or perform additional flipping operations, significantly shortening printing time and improving printing efficiency. Furthermore, the timing and location of ink penetration into both sides of the printing medium during simultaneous printing mitigate the tension differences caused by sequential ink penetration, reducing the impact of tension differences on printing quality. In addition, the data processing method during printing is simple and efficient, and the optimized ink volume better meets the needs of duplex inkjet printing, improving printing quality and efficiency, and enhancing user satisfaction. Attached Figure Description

[0053] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, and these are all within the protection scope of the present invention.

[0054] Figure 1 This is a schematic diagram of the structure of the double-sided inkjet printing device in an embodiment of the present invention.

[0055] Figure 2 This is a schematic diagram of the placement of the printing medium in an embodiment of the present invention.

[0056] Figure 3 This is a flowchart illustrating the double-sided inkjet printing method in an embodiment of the present invention.

[0057] Figure 4 This is a schematic diagram of the first printed data in an embodiment of the present invention.

[0058] Figure 5 This is a schematic diagram of the second printed data in an embodiment of the present invention.

[0059] Figure 6 This is a schematic diagram of misaligned front and back images in an embodiment of the present invention.

[0060] Figure 7 This is a schematic diagram of data processing in an embodiment of the present invention.

[0061] Figure 8a This is a schematic diagram of the alignment of the front and back images in an embodiment of the present invention.

[0062] Figure 8b This is a schematic diagram of the alignment deviation in an embodiment of the present invention.

[0063] Figure 9 This is a schematic diagram of centered printing in an embodiment of the present invention.

[0064] Figure 10 This is a schematic diagram of the structure of a double-sided inkjet printing device according to an embodiment of the present invention.

[0065] Figure 11 This is a schematic diagram of the control system of a duplex inkjet printing device according to an embodiment of the present invention. Detailed Implementation

[0066] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to 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 practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the invention.

[0067] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0068] Example 1

[0069] This invention provides a double-sided inkjet printing device, such as... Figure 1 As shown, the duplex inkjet printing device includes a first printing carriage 5, a second printing carriage 6, and a crossbeam 4. The crossbeam 4 is equipped with a synchronous belt 3, a drive wheel 1, and a driven wheel 2. A drive mechanism (not shown) drives the drive wheel 1 to rotate while simultaneously driving the driven wheel 2 to rotate via the synchronous belt 3. Both the first printing carriage 5 and the second printing carriage 6 are mounted on the synchronous belt 3 of the crossbeam 4 and are respectively positioned on opposite sides of the crossbeam 4. For example, the first printing carriage 5 is mounted on the front side 41, and the second printing carriage 6 is mounted on the rear side 42. The synchronous belt 3 can drive the first printing carriage 5 to reciprocate along the main scanning direction X (also known as the printing direction) on the front side 41 and the second printing carriage 6 on the rear side 42. The duplex inkjet printing system provided by this embodiment of the invention eliminates the need for a double crossbeam, a double control system, and a double drive structure, effectively reducing costs and enabling high-quality duplex inkjet printing results even with a low-cost machine structure and control system.

[0070] like Figure 2As shown, when double-sided printing is required, the printing medium 8 is vertically (perpendicular to the horizontal plane) positioned between the first printing carriage 5 and the second printing carriage 6, passing through the crossbeam 4 and the synchronous belt 3. Preferably, the printing origins (i.e., printing start points) of the first and second printing carriages 5 and 6 are respectively located at both ends of the crossbeam 4. For example, the printing origin of the first printing carriage 5 is located at the right end 43 of the crossbeam 4, and the printing origin of the second printing carriage is located at the left end 44 of the crossbeam 4. When the drive structure drives the drive wheel 1 to rotate and drives the first printing carriage 5 to move from left to right through the synchronous belt 3, it simultaneously drives the second printing carriage 6 to move synchronously from left to right. Since the first and second printing carriages 5 and 6 are located on the same crossbeam, their printing heights relative to the printing medium are the same. Thus, inkjet printing on both sides is performed at the same height position on the printing medium at the same time. The time and position of ink penetration into the front and back sides of the printing medium are close, thereby reducing the tension difference between the front and back sides caused by the ink penetrating sequentially and reducing the impact of tension difference on the printing effect. Furthermore, the data transmission method of this duplex inkjet printer is similar to that of the single-sided inkjet printer. Only special data processing is required for the printing data on the reverse side, which greatly reduces development costs and trial and error costs. It can help users quickly switch from single-sided printing to duplex printing, minimize development cycle and trial and error costs, and bring users faster economic benefits from rapid iteration.

[0071] Based on the above-mentioned duplex inkjet printing equipment, please refer to Figure 3 This invention also provides a double-sided inkjet printing method, which specifically includes:

[0072] S1: Obtain the image to be printed, and perform rasterization processing on the image to be printed to obtain the first printing data;

[0073] S2: Expand the first printed data to obtain the second printed data;

[0074] S3: Extract the third and fourth print data from the second print data respectively;

[0075] S4: Process the fourth printed data to obtain the fifth printed data;

[0076] S5: Send the third printing data and the fifth printing data to the first printing carriage and the second printing carriage respectively, drive the first printing carriage and the second printing carriage to move synchronously towards or in opposite directions at the same printing height and spray ink onto the front and back sides of the printing medium to form an image.

[0077] In this embodiment of the invention, the printing of identical and mirror-image double-sided images on a printing medium is used as an example to illustrate how to control the double-sided inkjet printing device to perform double-sided printing. Specifically, firstly, the image to be printed is acquired, which can be a bitmap or a vector image. The image to be printed is input into the image rasterization processor (such as RIP software) of the host computer (such as a PC) of the double-sided inkjet printing device for rasterization processing to obtain PRN format printing data that the double-sided inkjet printing device can recognize, which is denoted as the first printing data. Since double-sided printing is required, the first printing data is only sufficient for printing on one side. Therefore, the first printing data needs to be expanded to obtain sufficient printing data for double-sided printing. After expanding the first print data, second print data for double-sided printing is obtained. During printing, the second print data needs to be split while printing. The third print data for printing the front side is extracted and distributed to the first printing carriage, and the fourth print data for printing the back side is extracted and distributed to the second printing carriage. Since the back image is a mirror image of the front image, the fourth print data is processed before being sent to the second printing carriage to obtain the fifth print data, ensuring that the image is correctly printed on the back of the printing medium. Furthermore, to reduce the impact of tension differences on the printing effect, in this embodiment of the invention, the first and second printing carriages are respectively positioned at both ends of the printing medium before printing, such as... Figure 2As shown, the first printing carriage is positioned at the left end of the printing medium, and the second printing carriage is positioned at the right end of the printing medium. The printing (position) height of the first and second printing carriages is the same. After receiving the third printing data, the first printing carriage starts inkjet printing from the printing start point on the front side of the right end of the printing medium. Similarly, after receiving the fifth printing data, the second printing carriage starts inkjet printing from the printing start point on the back side of the left end of the printing medium. Since the first and second printing carriages are both mounted on the same synchronous belt, when the first printing carriage is driven to move from right to left (scan) on the front side of the crossbeam to print a pass on the front side of the printing medium, it will simultaneously drive the second printing carriage to move from left to right (scan) on the rear side of the crossbeam to print a pass on the back side of the printing medium. After completing one pass print, the printing medium is controlled to move a certain distance relative to the crossbeam along the sub-scanning direction Y (or stepping direction). Then, the first printing carriage is controlled to move from left to right in front of the crossbeam to print the next pass on the front side of the medium. Similarly, the second printing carriage moves from right to left behind the crossbeam to print the next pass on the back side of the medium... The first and second printing carriages are controlled to move back and forth in this scanning motion until the images on both sides are printed. In each pass print, the printing area on both sides is at the same height, and the ink penetrates into the printing medium at similar times and positions. This reduces the tension difference between the front and back sides caused by the ink penetrating sequentially, thus reducing the impact of tension difference on the printing effect and improving print quality.

[0078] In one embodiment, the image to be printed is a color image. Color images are typically printed using C (cyan) M (magenta) Y (yellow) K (black) inks. The first print data obtained after rasterizing the image to be printed includes first black channel data, first cyan channel data, first magenta channel data, and first yellow channel data, such as... Figure 4 The image shown is an example of the data format for the first print data: a file header followed by rows of data for each color channel. Each row of color channel data corresponds to the ink dot data for each pixel row in the printed image. For example, the first black channel data in row 0 corresponds to the black ink dot data for the pixels in row 0 of the front view image; the first cyan channel data in row 0 corresponds to the cyan ink dot data for the pixels in row 0 of the front view image, and so on. The black, cyan, magenta, and yellow ink dots, viewed macroscopically, form a color image.

[0079] In this invention, the printed images on both sides are identical and mirror images. Preferably, the step of expanding the first printed data to obtain the second printed data includes:

[0080] Copy the first black channel data, first cyan channel data, first magenta channel data, and first yellow channel data of the i-th row of the first printed data respectively to obtain the second black channel data, second cyan channel data, second magenta channel data, and second yellow channel data of the i-th row;

[0081] Insert the second black channel data, second cyan channel data, second magenta channel data, and second yellow channel data of the i-th row between the first black channel data, first cyan channel data, first magenta channel data, and first yellow channel data of the i-th and i+1-th rows to obtain the second print data;

[0082] Where i = 0, 1, 2, ..., N-1, and N is a natural number greater than or equal to 1.

[0083] Specifically, such as Figure 5 As shown, the first black channel data, first cyan channel data, first magenta channel data, and first yellow channel data of rows 0, 1, ..., N-1 are copied to obtain the second black channel data, second cyan channel data, second magenta channel data, and second yellow channel data of the corresponding rows. The second black channel data, second cyan channel data, second magenta channel data, and second yellow channel data of row i are then inserted between the first black channel data, first cyan channel data, first magenta channel data, and first yellow channel data of rows i and i+1, resulting in the final expanded second print data.

[0084] The second print data allows for printing images on both sides. During printing, the second print data needs to be split as it is being printed. The third print data, used for printing the front side, is extracted and distributed to the first printing carriage, while the fourth print data, used for printing the back side, is extracted and distributed to the second printing carriage. Preferably, the extraction of the third and fourth print data from the second print data includes:

[0085] The first black channel data, the first cyan channel data, the first magenta channel data, and the first yellow channel data are extracted sequentially from the second print data according to the row number and used as the third print data;

[0086] The second black channel data, second cyan channel data, second magenta channel data, and second yellow channel data corresponding to the number of rows of the first black channel data, first cyan channel data, first magenta channel data, and first yellow channel data in the third print data are extracted from the second print data as the fourth print data.

[0087] Specifically, during printing, the control software of the duplex inkjet printer extracts the corresponding number of rows of data from the second print data based on the amount of data printed per pass and sends them to the printing carriage. For example, if a pass of print data includes one row of data for each color channel, then the first row of data for the first black channel, first cyan channel, first magenta channel, and first yellow channel (referred to as the third print data) will be extracted from the second print data and sent to the first printing carriage. Similarly, the corresponding number of rows of data for the second black channel, second cyan channel, second magenta channel, and second yellow channel (referred to as the fourth print data) will be extracted and sent to the second printing carriage. When the next pass is printed, the first row of data for the first black channel, first cyan channel, first magenta channel, and first yellow channel (the third print data) will be extracted and sent to the first printing carriage. Similarly, the corresponding number of rows of data for the second black channel, second cyan channel, second magenta channel, and second yellow channel (the fourth print data) will be extracted and sent to the second printing carriage.

[0088] Since the reverse image is a mirror image of the front image, the fourth print data is processed to obtain the fifth print data before being sent to the second printing carriage. Preferably, the data processing of the fourth print data to obtain the fifth print data includes:

[0089] The fourth printed data is mirrored to obtain mirrored printed data;

[0090] Determine whether the end of each line of data in the mirrored printed data contains blank data;

[0091] If so, the blank data is placed at the beginning of each line of data to obtain the fifth printed data;

[0092] If not, the mirror print data is the fifth print data.

[0093] Specifically, before data processing, the fourth print data and the third print data are identical. Because mirror printing of double-sided images is required, the fourth print data needs to be mirrored. This data processing is typically performed in the print control software of the duplex inkjet printer's host computer. At the end of each line of color channel data in the third and fourth print data, there may be blank data. Blank data does not drive the printhead to eject ink. When the print control software mirrors the fourth print data, it does not mirror the blank data; instead, it mirrors each line of non-blank data and then sets the blank data at the end of the non-blank data. This process will result in the image printout as follows: Figure 6As shown, assuming the printing start point is the edge of the printing medium, after printing according to the third printing data, the starting printing position 9 of the front image 11 is on the right edge of the printing medium. Due to the blank data at the end, there are some blank pixels 13 (blank images) on the left edge. After mirroring the fourth printing data, the blank data is still set at the end of each line of data. When printing the reverse image, the starting printing position 10 of the reverse image 12 is on the left edge of the printing medium, and there will be some blank pixels 14 (blank images) on the right edge of the reverse image, causing the front and back images to be misaligned. If the printing medium is a transparent material, this misalignment will greatly affect the double-sided printing effect. For example, assuming the image width after rasterization is 6434 pixels, and the number of bytes corresponding to each line of color channel data is 1612 bytes, using variable dot printing (2-bit halftone, which can use large, medium and small ink dots for printing), then 1 pixel requires 2 bits to represent, so 1 byte (8 bits) can represent 4 pixels. The bytes corresponding to each line of color channel data can store 1612*4=6448 pixels, that is, there are 6448-6434=14 blank pixels. Since 1 pixel occupies 2 bits, there are 14*2=28 bits of data that are blank data. If the printing precision is 360dpi, 14 / 360*25.4=0.988 mm, that is, it causes an alignment error of nearly 1 mm on both sides of the image.

[0094] To ensure image printing quality, preferably, it is determined whether each line of data in the fourth printed data after mirroring contains blank data at the end. If so, the blank data needs to be moved to the beginning of each line of data. This data processing yields the fifth printed data. For example, the fourth printed data is as follows: Figure 7 As shown, there is a blank data 0 in the last byte, byte K. In reality, the blank data in the mirrored printed data after mirroring is still at the end, i.e., byte K. Therefore, it is necessary to move the blank data to the beginning of the line to obtain the final fifth printed data. After data processing, the front and back images are obtained as follows. Figure 8a As shown, the blank pixels 13 of the front image 12 and the blank pixels 14 of the back image 12 are both on the left edge of the printing medium, and the front and back images are aligned.

[0095] However, it is worth noting that mechanical errors (such as printing carriage installation errors, stepping errors, etc.) are unavoidable in actual production, which may result in slight alignment deviations between the front and back images. Figure 9As shown, alignment deviations such as E1 in the X direction (hereinafter referred to as vertical alignment deviation), or E2 in the Y direction (hereinafter referred to as horizontal alignment deviation), or both may occur. In some applications with high precision requirements, even minute alignment deviations can affect product quality and lead to reduced customer satisfaction.

[0096] After processing the fourth print data to obtain the fifth print data, to ensure accurate alignment of the front and back images during actual printing, the first and second printing carriages are first controlled to print test images based on the third and fifth print data. The alignment of the front and back is determined based on the test images, and the third and fifth print data are further adjusted according to the alignment. In one embodiment, after obtaining the fifth print data, the process further includes:

[0097] The first printing carriage and the second printing carriage are controlled to print the first test image and the second test image on the front and back of the printing medium respectively according to the third printing data and the fifth printing data;

[0098] Obtain the vertical alignment deviation between the first test image and the second test image;

[0099] Based on the vertical alignment deviation, insert or delete several blank data at the beginning of each line of data in the third and / or fifth printed data.

[0100] Specifically, the third and fifth print data here can be one or more PASS data from the overall print data. A test image is printed using the third and fifth print data to determine if there is a vertical alignment deviation and its magnitude. Based on the vertical alignment deviation, blank data is inserted or deleted from the third or fifth print data during the actual printing process to correct it. For example, in duplex printing, each side is printed in 2-PASS mode with a printing resolution of 360dpi*360dpi. At the start of duplex printing, the first test image 91 and the second test image 92 are obtained from the 2-PASS data duplex printing. Figure 9 As shown, assuming the distance between the first test image 91 on the front side and the left edge of the printing medium (or the starting position of the left end printing) is 1.2mm, and the distance between the second test image 92 on the back side and the left edge of the printing medium (or the starting position of the left end printing) is 1mm, then the vertical alignment deviation is obtained based on the first and second test images as follows: Figure 9As shown in E1, the distance is 0.2mm. Based on the printing accuracy and alignment deviation, the number of blank data that need to be inserted or deleted is 3. During the actual printing process, 3 blank data can be deleted from the beginning of each line of data in the third print data to correct the alignment deviation, or 3 blank data can be deleted from the beginning of each line of data in the fifth print data, or 1 blank data can be deleted from the beginning of each line of data in the third print data, and 2 blank data can be deleted from the beginning of each line of data in the fifth print data. If there are no blank data at the beginning of the third and fifth print data, the alignment deviation can be corrected by inserting blank data. For example, assuming the distance between the first test image 91 on the front side and the left edge of the printing medium (or the starting position of the left end of the print) is 0mm, and the distance between the second test image 92 on the back side and the left edge of the printing medium (or the starting position of the left end of the print) is 0.2mm, the alignment deviation can be corrected by inserting 3 blank data at the beginning of the third print data or by inserting 3 blank data at the beginning of the fifth print data.

[0101] In one embodiment, when the number of blank data to be inserted or deleted, obtained based on the horizontal alignment deviation, is less than 1, the alignment deviation can be corrected by adjusting the ink volume values ​​corresponding to the first and last non-empty data in each row. For example, suppose... Figure 9 The vertical alignment deviation E1 obtained is 0.05. Based on the printing accuracy and the vertical alignment deviation, the number of blank data that need to be inserted or deleted is 0.7. At this time, the ink volume of the non-blank data at the beginning and end of each line of data in the third print data can be adjusted, such as increasing the ink volume of the first non-blank data in each line of data and decreasing the ink volume of the last non-blank data, in order to reduce the vertical alignment deviation.

[0102] In one embodiment, if a horizontal alignment deviation is also detected through the first test image and the second test image, after controlling the first printing carriage and the second printing carriage to print the first test image and the second test image on the front and back of the printing medium respectively according to the third printing data and the fifth printing data, the method further includes:

[0103] Obtain the horizontal alignment deviation between the first test image and the second test image;

[0104] Insert or delete several lines of blank data in the third and / or fifth printed data based on the horizontal alignment deviation. For example, such as... Figure 9As shown, assuming the horizontal alignment deviation E2 of the first test image 91 and the second test image 92 is 0.2mm, the number of blank data lines that need to be inserted or deleted is 3, based on the printing accuracy and the horizontal alignment deviation. In the subsequent actual printing process, 3 blank data lines can be inserted before the 0th data line in the third printing data (equivalent to moving the front image up by 0.2mm in the Y direction). Alternatively, if the preceding data in the fifth printing data (with the 0th data line as the preceding data line) includes multiple blank data lines, then 3 blank data lines can be deleted. Or, correction can be made by inserting 2 blank data lines before the third printing data and deleting 1 blank data line in the fifth printing data line.

[0105] In one embodiment, when the number of rows of blank data to be inserted or deleted, obtained based on the horizontal alignment deviation, is less than 1, it can be modified by adjusting the ink volume value corresponding to the data. For example, when... Figure 9 The horizontal alignment deviation E2 shown is 0.05mm. The number of blank data rows that need to be adjusted is 0.7. At this time, the ink volume corresponding to the 0th row of the third print data (corresponding to the bottom of the image) can be reduced, while the ink volume corresponding to the last row of the third print data (corresponding to the top of the image) can be increased to reduce the horizontal alignment deviation of the front and back images.

[0106] In one embodiment, the printed image is centered on both sides of the printing medium. In this case, it is necessary to calculate the starting printing position of the printed image; that is, the starting printing positions of the first printing carriage and the second printing carriage need to be obtained before printing. Preferably, obtaining the starting printing positions of the first printing carriage and the second printing carriage includes:

[0107] Obtain the maximum scanning width of the first printing carriage in the main scanning direction, and denote it as the first width;

[0108] Obtain the width of the image to be printed in the main scanning direction, and denote it as the second width;

[0109] The starting printing positions of the first printing carriage and the second printing carriage are obtained based on the first width and the second width.

[0110] Specifically, the maximum scanning width of the first printing carriage in the main scanning direction X refers to the maximum width of the image that the first printing carriage can print when moving along the main scanning direction (also known in the industry as machine width), denoted as the first width. The width of the image to be printed on the printing medium, i.e., the width of the image to be printed in the main scanning direction, is denoted as the second width. The starting printing positions of the first and second printing carriages can be calculated based on the first and second widths. For example, the first width is 2000mm, the second width is 1000mm, and (2000-1000) / 2 = 500mm. During printing, the first printing carriage starts from the printing origin at the right end of the crossbeam and moves 500mm from right to left along the main scanning direction before starting inkjet printing. Similarly, the second printing carriage starts from the printing origin at the right end of the crossbeam and moves 500mm from left to right along the main scanning direction before starting inkjet printing. Preferably, the mainboard control system of the lower-level inkjet printer performs automatic centering processing for image printing according to the above calculation method. After inputting the first width and the second width, the control system automatically calculates the starting printing position of the first printing carriage and the second printing carriage based on the above data, and controls the first printing carriage and the second printing carriage to start ejecting ink at the starting printing position to print the image. Figure 9 The diagram shown is an example of automatic centering printing in an embodiment of the present invention. The control system automatically calculates the starting printing position 17 of the front image 15 and the starting printing position 18 of the back image 16 based on the first width and the second width, so that the front and back images are printed in the center.

[0111] In practical applications, due to the different materials of the printing media, their ink absorption or carrying capacity varies. Since printing requires printing on both sides of the media, if the ink volume ejected by the printing carriage is too large, the ink from both sides will seep into the image on the opposite side, severely affecting the imaging effect and the final print quality. In one embodiment, to mitigate the impact of ink seepage between the two sides and improve the printing effect on both sides, the ink volume of the print data is adjusted by determining the optimal values ​​for ink carrying or absorption capacity of the printing media on both sides. Preferably, the first print data consists of dot data, and the step of expanding the first print data to obtain the second print data further includes:

[0112] Obtain the total ink volume corresponding to the first printed data;

[0113] The preferred values ​​for the amount of ink carried on the front and back sides of the printing medium are determined respectively, and are denoted as the first preferred ink amount and the second preferred ink amount;

[0114] The ink volume value corresponding to the point data is adjusted based on the total ink volume, the first preferred ink volume, and the second preferred ink volume.

[0115] Specifically, the preferred ink volumes on the front and back sides of the printing medium, namely the first and second preferred ink volumes, can be determined as follows: Through repeated inkjet tests, the ink volume at which ink is ejected onto the front side of the printing medium to form an image that meets preset requirements (e.g., the image density and color saturation of the front image meet requirements, but no ink seeps into the back side) is recorded as the first preferred ink volume. The second preferred ink volume is obtained using the same method. If the materials on both sides of the printing medium are the same, generally the first and second preferred ink volumes are the same.

[0116] The first print data is the image dot matrix data after rasterization of the image to be printed. The image dot matrix data is two-dimensional or higher-dimensional tensor data, which is composed of dot data. Each dot data is used to characterize the ink output of the corresponding nozzle. Taking 2-bit halftone processing (or rasterization processing) as an example, the dot data includes dot data 00, dot data 01, dot data 10, and dot data 11. For ease of description, dot data 00 is referred to as empty dot data, dot data 01 as small ink dot data, dot data 10 as medium ink dot data, and dot data 11 as large ink dot data. During printing, the ink volume differs for large, medium, and small ink droplets. For example, let's define the ink volume for large ink droplets as 10 PL (first ink volume 10 PL), medium ink droplets as 7 PL (second ink volume 7 PL), and small ink droplets as 5 PL (third ink volume 5 PL). If a certain print data (dot data) in the first print data is 11, then its corresponding ink droplet is a large ink droplet, and the ink volume ejected during inkjet printing is 10 PL. If a certain print data (dot data) in the first print data is 10, then its corresponding ink droplet is a medium ink droplet, and so on. The first, second, and third ink volumes can be determined based on the actual printing situation; the 10 PL, 7 PL, and 5 PL mentioned above are just examples. The total ink volume corresponding to the first print data can be calculated based on the ink volume corresponding to each dot data. The first print data is the data of one side (front or back) of the printing medium. Based on the total ink volume and the first preferred ink volume and the second preferred ink volume, it can be determined whether the amount of ink to be ejected will be greater than the preferred value of the amount of ink carried or absorbed by the front or back of the printing medium. If so, the ink volume corresponding to each point in the first print data can be adjusted accordingly to ensure that the amount of ink ejected will not exceed the preferred value of the amount of ink carried by the front or back of the printing medium.

[0117] Preferably, adjusting the ink volume value corresponding to the dot data based on the total ink volume, the first preferred ink volume, and the second preferred ink volume includes:

[0118] Determine whether the first difference between the total ink volume and the first preferred ink volume is greater than or equal to a preset threshold and / or whether the second difference between the total ink volume and the second preferred ink volume is greater than or equal to the preset threshold;

[0119] If so, obtain the ink volume adjustment value based on the first difference and / or the second difference;

[0120] Adjust one or more of the first ink volume, the second ink volume, and the third ink volume according to the ink volume adjustment value.

[0121] Specifically, in one embodiment, if the materials on both sides of the printing medium are the same, and their first preferred ink volume and second preferred ink volume are the same, then it is only necessary to determine whether the first difference between the first preferred ink volume and the total ink volume, or the second difference between the second preferred ink volume and the total ink volume, is greater than a preset threshold. This preset threshold can be determined based on the actual application. If it exceeds this threshold, it may cause the ink on both sides to penetrate and affect each other. In this case, it is necessary to reduce the amount of ink sprayed onto it, and correspondingly, the first printing data needs to be adjusted. For example, after obtaining the first difference or the second difference, it is possible to determine the ink volume adjustment value that needs to be reduced for the ink volume corresponding to the first printing data. Based on the ink volume adjustment value, one or more of the following can be adjusted: the ink volume of large ink droplets (first ink volume), the ink volume of medium ink droplets (second ink volume), or the ink volume of small ink droplets (third ink volume). For example, if the calculated ink volume adjustment value is 100PL, and the first print data consists of 100 large ink droplets, 100 small ink droplets, and 200 small ink droplets, the ink volume of only the 100 large ink droplets can be adjusted, for example, from 10PL to 9PL. This will reduce the total ink volume of the first print data by 100PL. When the first print data is subsequently expanded to obtain the second print data, and the third and fourth print data are extracted from the second print data (and processed to obtain the fifth print data) for double-sided printing, the ink volume corresponding to the large ink droplets in the third and fifth print data will also be reduced accordingly. This effectively reduces the impact of ink penetration between the two sides when the ink volume is too large.

[0122] In another embodiment, if the materials corresponding to the front and back sides of the printing medium are different, their first preferred ink volume and second preferred ink volume are different. In this case, it is necessary to compare them with the total ink volume of the first printing data to obtain different first and second differences. Based on the first and second differences, different ink volume adjustment values ​​for the front and back sides are obtained, which are respectively called the first ink volume adjustment value and the second ink volume adjustment value. When printing the front image, that is, printing according to the third printing data, the ink volume of the large ink drop data (i.e., the first ink volume), the ink volume of the medium ink drop data (i.e., the second ink volume), and the ink volume of the small ink drop data (i.e., the third ink volume) are adjusted according to the first ink volume adjustment value. When printing the back image, that is, printing according to the fifth printing data, the ink volume of the large ink drop data (i.e., the first ink volume), the ink volume of the medium ink drop data (i.e., the second ink volume), and the ink volume of the small ink drop data (i.e., the third ink volume) are adjusted according to the second ink volume adjustment value, thereby effectively reducing the influence of ink penetration between the front and back sides when the ink volume is too large.

[0123] In summary, the duplex inkjet printing method provided by this invention uses a driving mechanism to drive a first printing carriage and a second printing carriage to move synchronously in opposite directions at the same printing height, enabling simultaneous printing on both sides of the printing medium. Compared to existing duplex inkjet printing technologies, it eliminates the need to wait for ink to dry or perform additional flipping operations, significantly shortening printing time and improving printing efficiency. Furthermore, the timing and location of ink penetration into both sides of the printing medium during synchronous printing mitigate the tension difference caused by sequential ink penetration, reducing the impact of tension differences on printing quality. The duplex inkjet printing data processing method provided in this invention is simple and efficient, better adapting to the needs of duplex printing, improving printing quality and efficiency, and enhancing user satisfaction.

[0124] Example 2

[0125] Based on the above embodiment one, please refer to Figure 10 This invention provides a double-sided inkjet printing device 200, the device 200 comprising:

[0126] Data acquisition module 201 is used to acquire the image to be printed and perform rasterization processing on the image to be printed to obtain first printing data;

[0127] Data expansion module 202 is used to expand the first print data to obtain second print data;

[0128] Data extraction module 203 is used to extract third and fourth print data from the second print data respectively;

[0129] Data processing module 204 is used to process the fourth print data to obtain the fifth print data;

[0130] The printing module 205 is used to send the third printing data and the fifth printing data to the first printing carriage and the second printing carriage respectively, drive the first printing carriage and the second printing carriage to move synchronously towards or in opposite directions at the same printing height and spray ink onto the front and back sides of the printing medium to form an image.

[0131] Preferably, the first print data includes first black channel data, first cyan channel data, first magenta channel data, and first yellow channel data, each with N rows, and the data expansion module 202 includes:

[0132] The copying unit is used to copy the first black channel data, the first cyan channel data, the first magenta channel data and the first yellow channel data of the i-th row of the first printed data respectively, and obtain the second black channel data, the second cyan channel data, the second magenta channel data and the second yellow channel data of the i-th row;

[0133] The insertion unit is used to insert the second black channel data, the second cyan channel data, the second magenta channel data, and the second yellow channel data of the i-th row between the first black channel data, the first cyan channel data, the first magenta channel data, and the first yellow channel data of the i-th and i+1-th rows, to obtain the second print data;

[0134] Where i = 0, 1, 2, ..., N-1.

[0135] Preferably, the data extraction unit includes:

[0136] The first extraction unit is used to extract the first black channel data, the first cyan channel data, the first magenta channel data and the first yellow channel data from the second print data in order of row number as the third print data;

[0137] The second extraction unit is used to extract the second black channel data, the second cyan channel data, the second magenta channel data, and the second yellow channel data from the second print data, which correspond to the number of rows of the first black channel data, the first cyan channel data, the first magenta channel data, and the first yellow channel data in the third print data, as the fourth print data.

[0138] Preferably, the data processing module 204 includes:

[0139] The mirror processing unit is used to perform mirror processing on the fourth print data to obtain mirror print data;

[0140] The judgment unit is used to determine whether the end of each line of data in the mirrored printed data contains blank data;

[0141] The first acquisition unit is used to, if so, place the blank data at the beginning of each line of data to obtain the fifth print data;

[0142] The second acquisition unit is used to determine whether the mirror print data is the fifth print data.

[0143] Preferably, the device further includes:

[0144] The first width acquisition module is used to acquire the maximum scanning width of the first printing carriage in the main scanning direction, which is denoted as the first width.

[0145] The second width acquisition module is used to acquire the width of the image to be printed in the main scanning direction, denoted as the second width;

[0146] The starting print position acquisition module is used to acquire the starting print positions of the first print carriage and the second print carriage based on the first width and the second width.

[0147] Preferably, the device further includes:

[0148] The total ink acquisition module is used to acquire the total ink volume corresponding to the first printed data;

[0149] The ink volume is selected to determine the preferred values ​​of the ink volume carried on the front and back sides of the printing medium, respectively, and is denoted as the first preferred ink volume and the second preferred ink volume.

[0150] The adjustment module is used to adjust the ink volume value corresponding to the point data according to the total ink volume, the first preferred ink volume, and the second preferred ink volume.

[0151] Preferably, the dot data includes large ink dot data, medium ink dot data, and small ink dot data, and their corresponding ink amounts are respectively denoted as the first ink amount, the second ink amount, and the third ink amount, wherein the first ink amount > the second ink amount > the third ink amount. The adjustment module includes:

[0152] The comparison unit is used to determine whether the first difference between the total ink volume and the first preferred ink volume is greater than or equal to a preset threshold and / or whether the second difference between the total ink volume and the second preferred ink volume is greater than or equal to the preset threshold;

[0153] Ink volume adjustment value acquisition unit, used to acquire ink volume adjustment value based on the first difference and / or the second difference if the condition is met;

[0154] An adjustment unit is configured to adjust one or more of the first ink volume, the second ink volume, and the third ink volume according to the ink volume adjustment value.

[0155] In summary, the duplex inkjet printing apparatus provided in this invention uses a single drive mechanism to drive a first printing carriage and a second printing carriage to move synchronously towards or in opposite directions from both ends of the printing medium at the same printing height, enabling simultaneous printing on both sides of the medium. Compared to existing duplex inkjet printing technologies, this eliminates the need to wait for ink to dry or perform additional flipping operations, significantly shortening printing time and improving printing efficiency. Furthermore, the timing and location of ink penetration into both sides of the printing medium during synchronous printing mitigate the tension difference caused by sequential ink penetration, reducing the impact of tension differences on printing quality. In addition, the data processing method in this invention is simple and efficient, better adapting to the needs of duplex inkjet printing, improving printing quality and efficiency, and enhancing user satisfaction.

[0156] Example 3

[0157] Furthermore, the double-sided inkjet printing method of this invention can be implemented by a double-sided inkjet printing device. For example... Figure 1 Or such as Figure 2 As shown, the duplex inkjet printing device includes a first printing carriage and a second printing carriage. The printing medium is vertically positioned between the first and second printing carriages. The first and second printing carriages are driven by the same drive mechanism and can reciprocate along the main scanning direction. The first printing carriage ejects ink onto the front side of the printing medium to form an image, and the second printing carriage ejects ink onto the back side of the printing medium to form an image. Furthermore, the inkjet printing device also includes a host computer integrating a rasterization processor and printing control software. Figure 11 A schematic diagram of the hardware structure of the control system for a duplex inkjet printing device provided in an embodiment of the present invention is shown.

[0158] The control system of a duplex inkjet printer may include a processor 301 and a memory 302 storing computer program instructions.

[0159] Specifically, the processor 301 may include a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of the present invention.

[0160] Memory 302 may include mass storage for data or instructions. For example, and not limitingly, memory 302 may include a hard disk drive (HDD), floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, memory 302 may include removable or non-removable (or fixed) media. Where appropriate, memory 302 may be internal or external to a data processing device. In a particular embodiment, memory 302 is a non-volatile solid-state memory. In a particular embodiment, memory 302 includes 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 flash memory, or a combination of two or more of these.

[0161] The processor 301 reads and executes computer program instructions stored in the memory 302 to implement any of the duplex inkjet printing methods in the above embodiments.

[0162] In one example, the duplex inkjet printing equipment control system may also include a communication interface 303 and a bus 310. Wherein, as Figure 11 As shown, the processor 301, memory 302, and communication interface 303 are connected through bus 310 and complete communication with each other.

[0163] The communication interface 303 is mainly used to realize communication between various modules, devices, units and / or equipment in the embodiments of the present invention.

[0164] Bus 310 includes hardware, software, or both, that couples components of a duplex inkjet printer control system together. For example, and not limitingly, 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), HyperTransport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an Infinite Bandwidth 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 combinations of two or more of these. Where appropriate, bus 310 may include one or more buses. While specific buses are described and illustrated in embodiments of the invention, the invention contemplates any suitable bus or interconnect.

[0165] Example 4

[0166] Furthermore, in conjunction with the duplex inkjet printing method in the above embodiments, this invention can be implemented using a computer-readable storage medium. This computer-readable storage medium stores computer program instructions; when these computer program instructions are executed by the processor 301, they implement any of the duplex inkjet printing methods described in the above embodiments.

[0167] It should be clarified 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, detailed descriptions of known methods are 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. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of the present invention.

[0168] The functional blocks shown in the above-described structural diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this invention are programs or code segments used to perform the required tasks. The programs or code segments can be stored on a machine-readable medium or transmitted over a transmission medium or communication link via data signals carried in a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting 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, etc. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0169] It should also be noted that the exemplary embodiments mentioned in this invention describe methods or systems based on a series of steps or apparatus. However, this invention is not limited to the order of the steps described above; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0170] The above description is merely a specific embodiment of the present invention. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A duplex inkjet printing method based on ink volume optimization, characterized in that, The method is applied to a duplex inkjet printing device, wherein the duplex inkjet printing device includes a first printing carriage and a second printing carriage, the printing medium is vertically disposed between the first printing carriage and the second printing carriage, the first printing carriage and the second printing carriage can reciprocate along the main scanning direction under the drive of the same drive mechanism, the first printing carriage is used to eject ink to the front side of the printing medium to form an image, and the second printing carriage is used to eject ink to the back side of the printing medium to form an image, the method includes: Obtain the image to be printed, and perform rasterization processing on the image to be printed to obtain the first printing data; The first printed data is expanded to obtain the second printed data; Extract the third and fourth print data from the second print data respectively; The process of processing the fourth printed data to obtain the fifth printed data includes: performing mirror processing on the fourth printed data to obtain mirrored printed data, and then obtaining the fifth printed data. The third and fifth printing data are sent to the first and second printing carriages respectively, and the first and second printing carriages are driven to move synchronously towards or in opposite directions at the same printing height and spray ink onto the front and back sides of the printing medium to form an image. The first printed data is composed of dot data. Before expanding the first printed data to obtain the second printed data, the method further includes: obtaining the total ink volume corresponding to the first printed data; determining the preferred values ​​of the ink volume carried by the front and back sides of the printing medium, respectively denoted as the first preferred ink volume and the second preferred ink volume; and adjusting the ink volume value corresponding to the dot data according to the total ink volume and the first preferred ink volume and the second preferred ink volume. The process of processing the fourth printed data to obtain the fifth printed data further includes: The first printing carriage and the second printing carriage are controlled to print the first test image and the second test image on the front and back of the printing medium respectively according to the third printing data and the fifth printing data; Obtain the vertical alignment deviation between the first test image and the second test image; Based on the vertical alignment deviation, insert or delete several blank data at the beginning of each line of data in the third and / or fifth printed data; And / or: Obtain the horizontal alignment deviation between the first test image and the second test image; Based on the horizontal alignment deviation, insert or delete several lines of blank data in the third and / or fifth printed data.

2. The double-sided inkjet printing method based on ink volume optimization according to claim 1, characterized in that, The dot data includes large ink dot data, medium ink dot data, and small ink dot data, and their corresponding ink amounts are respectively denoted as the first ink amount, the second ink amount, and the third ink amount, wherein the first ink amount > the second ink amount > the third ink amount. The adjustment of the ink amount value corresponding to the dot data based on the total ink amount and the first preferred ink amount and the second preferred ink amount includes: Determine whether the first difference between the total ink volume and the first preferred ink volume is greater than or equal to a preset threshold and / or whether the second difference between the total ink volume and the second preferred ink volume is greater than or equal to the preset threshold; If so, obtain the ink volume adjustment value based on the first difference and / or the second difference; Adjust one or more of the first ink volume, the second ink volume, and the third ink volume according to the ink volume adjustment value.

3. The double-sided inkjet printing method based on ink volume optimization according to claim 1, characterized in that, When the materials on both sides of the printing medium are the same, the first preferred ink amount and the second preferred ink amount are the same; when the materials on both sides of the printing medium are different, the first preferred ink amount and the second preferred ink amount are different.

4. The double-sided inkjet printing method based on ink volume optimization according to claim 1, characterized in that, The first print data includes first black channel data, first cyan channel data, first magenta channel data, and first yellow channel data, each with N rows. Expanding the first print data to obtain the second print data includes: Copy the first black channel data, first cyan channel data, first magenta channel data, and first yellow channel data of the i-th row of the first printed data respectively to obtain the second black channel data, second cyan channel data, second magenta channel data, and second yellow channel data of the i-th row; Insert the second black channel data, second cyan channel data, second magenta channel data, and second yellow channel data of the i-th row between the first black channel data, first cyan channel data, first magenta channel data, and first yellow channel data of the i-th and i+1-th rows to obtain the second print data; Where i = 0, 1, 2, ..., N-1, and N is a natural number greater than or equal to 1.

5. The double-sided inkjet printing method based on ink volume optimization according to claim 4, characterized in that, The step of extracting the third and fourth print data from the second print data includes: The first black channel data, the first cyan channel data, the first magenta channel data, and the first yellow channel data are extracted sequentially from the second print data according to the row number and used as the third print data; The second black channel data, second cyan channel data, second magenta channel data, and second yellow channel data, which correspond one-to-one with the number of rows of the first black channel data, first cyan channel data, first magenta channel data, and first yellow channel data in the third print data, are extracted from the second print data as the fourth print data.

6. The double-sided inkjet printing method based on ink volume optimization according to claim 3, characterized in that, The process of mirroring the fourth printed data to obtain mirrored printed data to obtain the fifth printed data includes: Determine whether the end of each line of data in the mirrored printed data contains blank data; If so, the blank data is placed at the beginning of each line of data to obtain the fifth printed data; If not, the mirror print data is the fifth print data.

7. The double-sided inkjet printing method based on ink volume optimization according to claim 1, characterized in that, Before sending the third and fifth print data to the first and second print carriages respectively, and driving the first and second print carriages to move synchronously towards each other from both ends of the print medium at the same print height and spray ink onto both sides of the print medium to form an image, the process also includes: Obtain the maximum scanning width of the first printing carriage in the main scanning direction, and denote it as the first width; Obtain the width of the image to be printed in the main scanning direction, and denote it as the second width; The starting printing positions of the first printing carriage and the second printing carriage are obtained based on the first width and the second width.

8. A duplex inkjet printing device based on ink volume optimization, characterized in that, The device is applied to a duplex inkjet printing equipment, wherein the duplex inkjet printing equipment includes a first printing carriage and a second printing carriage, the printing medium is vertically disposed between the first printing carriage and the second printing carriage, the first printing carriage and the second printing carriage can reciprocate along the main scanning direction under the drive of the same drive mechanism, the first printing carriage is used to spray ink onto the front side of the printing medium to form an image, and the second printing carriage is used to spray ink onto the back side of the printing medium to form an image. The device includes: The data acquisition module is used to acquire the image to be printed and to perform rasterization processing on the image to be printed to obtain the first printing data. The data expansion module is used to expand the first printed data to obtain the second printed data; The data extraction module is used to extract the third and fourth print data from the second print data, respectively. The data processing module is used to process the fourth printed data to obtain the fifth printed data, including: performing mirror processing on the fourth printed data to obtain mirrored printed data to obtain the fifth printed data; wherein, after processing the fourth printed data to obtain the fifth printed data, the module further includes: controlling the first printing carriage and the second printing carriage to print a first test image and a second test image on the front and back sides of the printing medium respectively according to the third printed data and the fifth printed data; obtaining the vertical alignment deviation of the first test image and the second test image; inserting or deleting a number of blank data at the beginning of each line of data in the third printed data and / or the fifth printed data according to the vertical alignment deviation; And / or: Obtain the horizontal alignment deviation between the first test image and the second test image; insert or delete several rows of blank data in the third and / or fifth printed data according to the horizontal alignment deviation; The printing module is used to send the third printing data and the fifth printing data to the first printing carriage and the second printing carriage respectively, drive the first printing carriage and the second printing carriage to move synchronously towards or in opposite directions at the same printing height and spray ink onto the front and back sides of the printing medium to form an image; The total ink acquisition module is used to acquire the total ink volume corresponding to the first print data, wherein the first print data is composed of dot data; The ink volume is selected to determine the preferred values ​​of the ink volume carried on the front and back sides of the printing medium, respectively, and is denoted as the first preferred ink volume and the second preferred ink volume. The adjustment module is used to adjust the ink volume value corresponding to the point data according to the total ink volume, the first preferred ink volume, and the second preferred ink volume.

9. A duplex inkjet printing device based on ink volume optimization, characterized in that, The double-sided inkjet printing device includes a first printing carriage and a second printing carriage. The printing medium is vertically arranged between the first printing carriage and the second printing carriage. The first printing carriage and the second printing carriage can reciprocate along the main scanning direction under the drive of the same driving mechanism. The first printing carriage is used to spray ink onto the front side of the printing medium to form an image, and the second printing carriage is used to spray ink onto the back side of the printing medium to form an image. The duplex inkjet printing device further includes: at least one processor, at least one memory, and computer program instructions stored in the memory, which, when executed by the processor, implement the method as described in any one of claims 1-7.

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