Rapid printing method for ink-jet printer, and rapid printing device

Abstract

The present invention relates to inkjet printing technology. It provides a rapid printing method and a device. The method comprises the steps of: S1: moving the paper to be printed on at an even speed along its length direction, wherein M rows of nozzles are arranged along the length direction, and the interval between adjacent two rows of nozzles is M×N dot pitches, the dot pitch is the distance between two pixels of the printed product, M is a natural number no less than 2 and N is a natural number no less than 1; S2: firing the M rows of nozzles simultaneously at intervals of a first specified time, wherein each nozzle drops at most one ink droplet for each firing, each ink droplet corresponding to one pixel, the distance between ink droplets dropped in two successive firings is M dot pitches, and the total number of firings is N; S3: pausing the firings for a second specified time, and the ratio of the second specified time to the first specified time is (M-1):M; S4: alternately executing S2 and S3 until printing completed. This solution can effectively increase the printing speed and prevent the appearance of white lines that affect the printing effect.

Description

TECHNICAL FIELD

[0001] The present invention relates to the technical field of inkjet printing, and particularly to a rapid printing method and a device using inkjet printers.BACKGROUND ART

[0002] With the continuous development of printing technology, inkjet-based digital printing systems have become widely popular and gained extensive social recognition. Various types of digital printing equipment undertake different printing tasks, and their differences lie in the use of different printheads, which also result in different performance parameters and quality indicators.

[0003] In Single Pass Printing (also known as One Pass Printing), printheads are set in a row and kept stationary while the paper moves rapidly beneath them. Each nozzle of the printheads ejects ink droplets at a fixed frequency, creating a line on the paper. Numerous nozzles in the line create numerous parallel lines on the paper, and these dense lines form a square. As shown in Figure 1, some areas in the square have ink while others do not, thus creating the printed pattern. It is obvious that if a line of ink is to maintain a consistent density, the higher the frequency at which the printheads eject ink, the faster the paper must move. The printing speed is determined by the firing frequency, at which the printheads eject ink. The higher the firing frequency is, the faster the printing goes. However, printheads with high firing frequencies are often expensive and difficult to maintain.

[0004] In a current technical solution, nozzles are arranged in a row, with each nozzle independently controlling the firing time to print a complete pattern, as shown in Figure 2. The printing speed is entirely dependent on the firing frequency, which can hardly be increased. Moreover, if a nozzle becomes clogged, it will result in a white line, as shown in Figure 3, which can degrade the printing effect. Additionally, the probability of nozzle clogging is quite high.

[0005] Therefore, there is a need to provide a method and / or device based on inkjet printers that can effectively increase the printing speed and prevent the occurrence of a white line that affects the printing effect.

[0006] The information disclosed above is only for promoting the understanding of the background of this application and may contain some information that does not constitute the prior art known to those skilled in the art.SUMMARY OF INVENTION

[0007] The primary purpose of the present invention is to overcome the problem of low printing efficiency of inkjet printers and to provide a rapid printing method and rapid printing device for inkjet printers, which can effectively increase the printing speed and prevent a white line from affecting the printing effect.

[0008] To achieve the above purpose, the first aspect of the present invention provides a rapid printing method for inkjet printers, including the following steps: S1: Moving the paper to be printed on at an even speed along its length direction, wherein, M rows of nozzles are arranged along the length direction, and the interval between two adjacent rows of nozzles is M×N dot pitches, herein the dot pitch is the distance between two pixels of the printed product, M is a natural number no less than 2 and N is a natural number no less than 1. S2: Firing the M rows of nozzles simultaneously at intervals of a first specified time, wherein, for each firing, each nozzle drops at most one ink droplet, corresponding to one pixel, the distance between ink droplets dropped in two successive firings is M dot pitches, and the total number of firings is N. S3: Pausing the firings for a second specified time, and the ratio of the second specified time to the first specified time is (M-1):M. S4: Alternately executing S2 and S3 until printing completed.

[0009] In an example embodiment of the present invention, in step S1, the ink colors of the M rows of nozzles are the same.

[0010] In an example embodiment of the present invention, N is an integer multiple of 2, and the resolution in the length direction of the paper is N×12.5 dpi.

[0011] In an example embodiment of the present invention, the number of nozzles in each row is no less than 800, and the distance between each row of nozzles in the width direction of the paper is one dot pitch.

[0012] In an example embodiment of the present invention, each row of nozzles includes two staggered columns of nozzles, and the number of nozzles in each column is no less than 400.

[0013] In an example embodiment of the present invention, the distance between two adjacent nozzles in each column is 2 dot pitches.

[0014] Preferably, M is 4, N is 48, and the dot pitch is 1 / 600 inches.

[0015] In an example embodiment of the present invention, in step S2, no ink droplets are dropped for pixels that do not need to be printed.

[0016] In an example embodiment of the present invention, in step S2, the first row of nozzles does not drop ink droplets during the Nth firing.

[0017] As the second aspect of the present invention, a rapid printing device is provided, which can implement the rapid printing method.

[0018] In an example embodiment of the present invention, the rapid printing device includes an ink tank, a printhead, and a control unit, wherein the ink tank is connected to the printhead used to provide with ink, the printhead includes M rows of nozzles, and the control unit is communicatively connected to the printhead, controlling the printhead's firing and dropping ink droplets onto the paper.

[0019] The advantageous effect of the present invention is that by setting M rows of nozzles and adjusting the firing interval time every N firings, a high-frequency effect is achieved with a low-frequency firing frequency, reducing the cost of the printhead, reducing the defects caused by nozzle clogging, and increasing the printing speed by M-1 times.BRIEF DESCRIPTION OF DRAWINGS

[0020] The above and other objectives, features and advantages of the present application will become more apparent through a detailed description of its example embodiments with reference to the accompanying drawings. The accompanying drawings described below are merely used in examples of the present application. For those skilled in the art, other drawings can be obtained without creative labor based on these drawings. Figure 1 schematically shows an effect picture of single pass printing. Figure 2 schematically shows the printing effect picture of a row of nozzles in parallel. Figure 3 schematically shows the printing effect picture of a row of nozzles in parallel with clogged nozzles. Figure 4 schematically shows the schematic picture of M rows of nozzles of the printhead. Figure 5 schematically shows the structure picture of the printhead (excluding the ink channel). Figure 6 schematically shows the structure picture of the printhead (including the ink channel). Figure 7 is a step diagram using the rapid printing method according to the present invention. Figure 8 is a schematic effect picture of printing with a multi-color printhead. Figure 9 gives a schematic diagram of the rapid printing method of the inkjet printer. Figure 10 illustrates an effect comparison of inkjet printing. DESCRIPTION OF EMBODIMENTS

[0021] Now, some example embodiments will be given with reference to the attached drawings. However, these embodiments can be implemented in various forms and should not be construed as being limited to the embodiments described herein; rather, these embodiments are provided to make the application complete and to fully convey the concept of the example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar parts, and thus their repetitive description will be omitted.

[0022] In addition, the features, structures, or characteristics described herein may be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to give a thorough understanding of the embodiments of the application. However, those skilled in the art will recognize that the application can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other cases, well-known methods, components, materials, or operations are not described in detail to avoid obscuring the aspects of the application.

[0023] The block diagrams shown in the drawings are merely functional entities and do not necessarily correspond to physically separate entities. That is, these functional entities can be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0024] The flow diagram shown in the drawings are merely illustrative and do not necessarily include all the contents and operations / steps, nor do they necessarily have to be executed in the described order. For example, some operations / steps can be decomposed, while others can be combined or partially combined. Therefore, the actual execution order may be changed according to the actual situation.

[0025] It should be understood that although the terms "first", "second", "third", etc. may be used herein to describe various components, these components should not be limited by these terms. These terms are used to distinguish one component from another. Therefore, the first component described herein can be referred to as the second component without departing from the teachings of the application. As used herein, the term "and / or" includes any one of the associated listed items and all combinations thereof.

[0026] Those skilled in the art can understand that the drawings are merely schematic diagrams of the example embodiments, and the modules or processes in the drawings are not necessarily essential for implementing the application, and thus cannot be used to limit the protection scope of the application.

[0027] According to the first aspect of the present invention, a rapid printing device is provided, including an ink tank, a printhead and a control unit, wherein the ink tank is connected to the printhead used to provide with ink, the printhead includes M rows of nozzles and M ink channels, and the control unit is communicatively connected to the printhead, controlling the printhead's firing and dropping ink droplets onto the paper

[0028] As shown in Figures 4, 5, and 6, the M rows of nozzles are arranged at the bottom of the printhead to spray ink onto the paper below the printhead. Every two adjacent rows of nozzles are spaced at a specified distance, which is N×M dot pitches. A dot pitch is the distance between two pixel points of the printed product. The number of nozzles in each row is no less than 800, and the distance of each row of nozzles in the width direction of the paper is one dot pitch. Each row of nozzles includes two columns in which nozzles are disposed staggerly, and the number of nozzles in each column is no less than 400. The distance between two adjacent nozzles in each column is two dot pitches. Staggering the nozzles of the two columns, each row having no less than 400 nozzles, achieves the same printing effect as setting nozzles in a row with one dot pitch's distance between adjacent nozzles, equivalent to each row having no less than 800 nozzles.

[0029] In an example shown in Fig.4, M is 4, an interval of 8.128mm (i.e., 192 pixel points, or 192 / 600 inches) is for the adjacent rows, and 1.016mm (i.e., 24 pixel points) for the two columns in one row, 0.085mm (i.e., 2 pixel points) for the adjacent nozzles in one column. Each column has 400 nozzles, and an interval of 0.042mm (i.e., 1 pixel point) is set for the two nozzles with same sequence numbers in the two adjacent columns in the width direction of the paper. There are a total of 8 columns of nozzles in Figure 4. They are orderly, from right to left, column A, column B, column C, column D, column E, column F, column G and column H as shown in Figure 5. The staggered arrangement of adjacent columns can improve the resolution of inkjet printing. As shown in Figure 6, there are four ink channels. From right to left, the first one is connected to B column and G column, the second one connected to A column and H column, the third one connected to C column and F column, and the fourth one connected to D column and E column. The colors of the four ink channels are the same, ensuring that the ink colors of the M rows of nozzles are consistent. The ink channels are connected to non-adjacent columns to eliminate the influence of static electricity.

[0030] The control unit instructs the printhead to fire all M rows of nozzles simultaneously at the first specified time interval. During each firing, each nozzle ejects at most one ink droplet, and each ink droplet corresponds to one pixel point. The interval between two rows of ink droplets is (M-1) pixel points, that is, the interval between ink droplets ejected in two firings is M dot pitches. Firing occurs N times, and N firings form a group. There is a pause of the second specified time interval between each group of firings. Multiple groups of firings are repeated until printing is completed. The ratio of the second specified time interval to the first specified time interval is (M-1):M.

[0031] As a second aspect, the present invention provides a method for rapid printing using the device of the first aspect above described. As shown in Figure 7, it includes the following steps: S1: Moving the paper at an even speed along its length direction.

[0032] The paper moves on the digital printing machine, and there is an encoder on the printing machine that changes along with the position of the paper. The control board determines the current position of the paper and whether firing is needed based on the scale on the encoder. In this method, the speed of paper movement can be increased by (M-1) times. To be specific, assuming the inkjet resolution along the length direction of the paper is 600dpi, the firing frequency is 21KHz, and there are four ink channels, then in the traditional point-by-point inkjet method, the maximum speed of paper movement is 21000 / 600×25.4 = 889mm / s, or 53.3 meters per minute. However, according to the method herein, the speed can be increased to three times, that is, 160 meters per minute.

[0033] M rows of nozzles are set along the length direction of the paper, and the interval between two adjacent rows of nozzles is M×N dot pitches, wherein the dot pitch is the interval between two pixel points of the printed product. M is a natural number no less than 2, and N is a natural number no less than 1.

[0034] The interval between the two adjacent rows of nozzles is a specified distance, which is N×M dot pitches. Each row of nozzles includes two staggerly disposed columns of nozzles, and the number of nozzles in each column is no less than 400.

[0035] The ink colors of the M rows of nozzles are the same.

[0036] Preferably, M is 4, N is 48, and the dot pitch is 1 / 600 inches.

[0037] S2: all M rows of nozzles firing simultaneously at the first specified time interval. During each firing, each nozzle can eject at most one ink droplet, and each ink droplet corresponds to one pixel point. The interval between ink droplets ejected in two consequent firings is M dot pitches. Firing occurs N times.

[0038] Ink droplets are not ejected for pixels that do not need to be printed.

[0039] The number of firings is determined based on the dot pitch, the interval between two rows of nozzles, and the number of nozzle rows. N is an integer multiple of 2, and the resolution along the length direction of the paper is N×12.5dpi, and the dot pitch is 1 / (N×12.5) inches.

[0040] Preferably, since the ink droplets ejected by the first row of nozzles during the Nth firing overlap with those of the subsequent nozzles, to reduce redundant ink ejection, the first row of nozzles does not eject ink droplets during the Nth firing. S3: Pause the firing for a second specified time, the ratio of the second specified time to the first specified time being (M-1):M; S4: Alternately executing S2 and S3 until printing is completed.

[0041] Steps S2 and S3 are repeated M times.

[0042] The advantages of the rapid printing method of the inkjet printer are illustrated in detail through the following examples.

[0043] Figure 8 is a schematic diagram printed by a multi-color printhead. The multi-color printhead has multiple rows of nozzles arranged side by side. According to the traditional method, each row of nozzles is used to eject ink of a different color, typically CMYK four-color ink. In Figure 8, from right to left, they are the four colors of CMYK. As the paper moves, the four-color ink droplets are ejected at the same position, presenting various colors due to different combinations of ink, thereby achieving color printing.

[0044] According to the method of the present invention, the multi-color nozzles eject the same color and stagger the ink dots so that the ink does not print at the same position. The four rows of nozzles print different lines respectively, and they complement each other. Different nozzles do not print on the same pixel point, forming a complete image. As mentioned above, each row of nozzles contains two columns that are offset from each other (as shown in Figures 4 and 5), placed closely together to improve the horizontal resolution. For ease of description, it is still said that there are a total of four rows here.

[0045] As shown in Figure 9, for an Epson i3200 printhead, taking 600 dpi as an example, the ink droplet interval, that is, 1 / 600 inch, is used as the dot pitch. The printhead has a total of four rows, as shown in Figure 4, and the interval between adjacent rows of nozzles is 192 dot pitches. First, confirm that M is 4 and N is 48.

[0046] If each nozzle fires every three points, the resolution will become 150 dpi, and the paper movement speed can be increased to four times the original. Each row of nozzles is fired simultaneously. After completing 48 firings, at the 49th firing, the paper has moved 48 * 4 = 192 dot pitches, that is, the position of the paper corresponding to the second row of nozzles coincides with the position corresponding to the first row of nozzles during the first firing. Thus, ink is ejected multiple times at the same position, while adjacent positions remain blank. As shown in the upper two diagrams of Figure 9, the paper moves from right to left, and the four rows of nozzles fire simultaneously. After the first row of nozzles finishes firing, after a period of time, the second row of nozzles will fire at the same position, and the ink droplet positions will overlap, with a gap between the two ink droplets.

[0047] To avoid this phenomenon, the solution according to the present invention is: after 48 firings at an interval of 4 dot pitches, the next firing time is advanced by one quarter, that is, 3 dot pitches, thereby staggering the ink droplets that would other overlap by one dot pitch. Then, perform 48 firings at an interval of 4 dot pitches, followed by one firing at an interval of 3 dot pitches, and repeat this cycle. As shown in Figure 9, in the third diagram of Figure 9, if the second row of nozzles from the left fires again after 48 firings at an interval of 4 dot pitches, the ink droplets ejected by the second row of nozzles will overlap with those of the first row of nozzles. To avoid this overlap, there are three blank points between each pair of adjacent ink droplets. By shortening the interval time corresponding to one dot pitch to fire the nozzles, they will drop ink on a blank point, supplementing the inkjet image; after 48 firings, fire 48 times again at an interval of 3 dot pitches. As shown in the fourth diagram of Figure 9, the inkjet images are staggered and complement each other, thereby increasing the resolution from 150 dpi to 600 dpi. In other words, every first designated time, the 4 rows of nozzles are fired simultaneously. For each firing, the nozzle only drops one ink droplet, and each ink droplet corresponds to one pixel. Ink droplets are not dropped for pixels that do not need to be printed. There is a 3-pixel gap between each two rows of ink droplets. firing occurs N times, with N being 48 as a group. There is a pause of the second designated time after each group of firings. The ratio of the second designated time to the first designated time is (M-1):M.. Since the printing distance only triples during the firing switch between two groups (i.e., after the pause of the second designated time), the final speed is determined by the lowest speed in the entire process. Therefore, the paper movement speed triples compared to the original speed.

[0048] From the above described, it can be seen that the firing frequency remains unchanged, but the paper movement speed increases to three times. The scheme in this example uses a lower frequency firing to print out an ink droplet density under a higher frequency. If there are more rows of nozzles, the paper movement speed will be even faster. The paper movement speed is (M-1) times that of row-by-row printing. Moreover, since the ink dots in the same column are alternately ejected by four rows of nozzles in this scheme, if one nozzle is blocked, it will not block the entire column of ink dots as shown in Figure 3, but only one quarter (1 / M) of the ink dots in the column. This significantly improves the situation of nozzle blockage. As shown in Figure 10, the inkjet effect comparison diagram, the top represents the complete inkjet pattern, and the bottom represents the inkjet situation after one nozzle is blocked, with only one quarter of the ink dots not being ejected.

[0049] The relationship between inkjet positions and firing is shown in Table 1. Table 1. Firing positions of nozzles in different rowsSequence Number of firing1 st< Row Nozzles2 nd< Row Nozzles3 rd< Row Nozzles4 th< Row Nozzles1327311415519623727831935103911431247135114551559166317671871197520792183228723912495259926103271072811129115301193112332127331313413535139361433714738151391554015941163421674317144175451794618347187481914919425019865120210522061453210185421422552182656222305722634582303859234426023846612425062246546325058642546265258666626270672667468270786927482702788671282907228694732909874294102752981067630211077306114783101187931412280318126813221308232613483330138843341428533814686342150873461548835015889354162903581669136217092366174933701789437418295378186963821909738519319838919759939320191003972051310140120917102405213211034092172510441322129105417225331064212293710742523341108429237451094332414911043724553111441249571124452536111344925765114453261691154572657311646126977117465273811184692778511947328189120477285931214812899712248529310112348929710512449330110912549730511312650130911712750531312112850931712512951332112913051732513313152132913713252533314113352933714513453334114913553734515313654134915713754535316113854935716513955336116914055736517314156136917714256537318114356937718514457338118914557638419201465803881964147584392200814858839620412149592400208161505964042122015160040821624152604412220281536084162243215461242022836155616424232401566204282364415762443224048158628436244521596324402485616063644425260161640448256641626444522606816364845626472164652460268761656564642728016666046827684167664472280881686684762849216967248028896170676484292100171680488296104172684492300108173688496304112174692500308116175696504312120176700508316124177704512320128178708516324132179712520328136180716524332140181720528336144182724532340148183728536344152184732540348156185736544352160186740548356164187744552360168188748556364172189752560368176190756564372180191760568376184192764572380188193767575383191194771579387195195775583391199196779587395203197783591399207198787595403211199791599407215200795603411219201799607415223202803611419227203807615423231204811619427235205815623431239

[0050] As can be seen from Table 1, the first group was fired or fired 48 times, with the first row of nozzles spraying from the position of the 3rd point to the 191st point at intervals of 4 dot pitches; the second group was fired 48 times, with the ink sprayed one dot pitch forward, the first row of nozzles spraying from the position of the 194th point to the 382nd point at intervals of 4 dot pitches, and the second row of nozzles spraying from the position of the 2nd point to the 190th point at intervals of 4 dot pitches; the third group was fired 48 times, with the ink sprayed one dot pitch forward again, the first row of nozzles spraying from the position of the 385th point to the 573rd point at intervals of 4 dot pitches, the second row of nozzles spraying from the position of the 193rd point to the 381st point at intervals of 4 dot pitches, and the third row of nozzles spraying from the position of the 1st point to the 189th point at intervals of 4 dot pitches; the fourth group was fired 48 times, with the ink sprayed one dot pitch forward again, the first row of nozzles spraying from the position of the 576th point to the 764th point at intervals of 4 dot pitches, the second row of nozzles spraying from the position of the 384th point to the 572nd point at intervals of 4 dot pitches, the third row of nozzles spraying from the position of the 192nd point to the 380th point at intervals of 4 dot pitches, and the fourth row of nozzles spraying from the position of the 0th point to the 188th point at intervals of 4 dot pitches, and so on. By supplementing the pixel positions in the front row with the nozzles in the rear row in this way, the paper speed can be increased to three times the original speed while maintaining the printing resolution unchanged.

[0051] The firing times that are multiples of 48 are the position switching points. As long as the first row of nozzles does not spray during this firing, all positions will be sprayed once without any repeated ink spraying, thus enabling the complete printing of the entire image.

[0052] By the same token, if the distance between two adjacent rows of nozzles is set at 8.128mm, the number of ink dots between two adjacent rows of nozzles at 25dpi is 8.128 / 25.4*25=8. If the resolution is an integer multiple of 25, the number of ink droplets between two rows of nozzles will be an integer multiple of 8. Also, if M is set as 4 and N as 2, a new printing mode can be gained in this pattern. If the new resolution is a multiple of 25 dpi, for example, 600 dpi, which is 24 times 25 dpi, then N = 24 * 2 = 48. By the discipline of printing once for every M pixels, after every N times' printing, during which 4 * N rows of dots are printed, the printing position is switched once by adjusting the interval time, changing position 4 to position 3. Then, print 4 * N rows of dots again and change position 3 to position 2. Then, print 4 * N rows of dots again and change position 2 to position 1. After the position adjustment, the first pixel of the first row of nozzles is not printed, or the last pixel before the adjustment is not printed, thus the image can be perfectly printed without any omission or repetition of dots.

[0053] According to the embodiment of the present invention, by adjusting the time interval of firings between two successive firing groups based on the interval between two ink droplets, ink droplets are supplemented for staggered positions. The effect of increasing the paper movement speed to M-1 times without degrading printing resolution can be achieved only if ensuring the interval between two adjacent rows of nozzles to be M×N dot pitches and the interval between the two ink droplets formed by two successive firings to be M dot pitches.

[0054] The above description specifically shows and describes the example embodiments of the present invention. It should be understood that the present invention is not limited to the detailed structure, setting method or implementation method described here. On the contrary, the present invention intends to cover various modifications and equivalent settings within the spirit and scope of the appended claims.

Claims

1. A method for rapid printing by inkjet printers, <b>characterized by including the following steps: S1: Moving the paper to be printed on at an even speed along its length direction, wherein, M rows of nozzles are provided along the length direction, and the interval between the two adjacent rows of nozzles is M×N dot pitches, the dot pitch is the distance between two pixels of the printed product, M is a natural number no less than 2 and N is a natural number no less than 1; S2: Firing the M rows of nozzles simultaneously at intervals of a first specified time, wherein each nozzle drops at most one ink droplet for each firing, each ink droplet corresponding to one pixel, the distance between ink droplets dropped in two successive firings is M dot pitches, and the total number of firings is N; S3: Pausing the firings for a second specified time, and the ratio of the second specified time to the first specified time is (M-1):M; S4: Alternately executing S2 and S3 until printing completed.

2. The method according to claim 1, characterized in that the ink color of the M rows of nozzles in step S1 is the same.

3. The method according to claim 1, characterized in that N is an integer multiple of 2, and the resolution in the length direction of the paper is N×12.5 dpi.

4. The method according to claim 1, characterized in that in step S2, no ink droplet is dropped at the pixel points that do not need to be printed.

5. The method according to claim 1, characterized in that in step S2, the first row of nozzles does not drop an ink droplet at the Nth firing.

6. A device for rapid printing, characterized by using the method as claimed in any one of claims 1 to 5.

7. The device according to claim 6, characterized by including an ink tank, a printhead and a control unit, wherein the ink tank is connected to the printhead to provide ink, the printhead includes M rows of nozzles, and the control unit is communicatively connected to the printhead and used to control the printhead to fire and drop ink droplets onto the paper.

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