Method and system for aligning an ink drop observer

Abstract

The present invention relates to a method for aligning an ink droplet observer, comprising the steps of: identifying an inkjet printhead to be detected, controlling the inkjet printhead to eject a first ink droplet from a starting nozzle, adjusting the relative position of the inkjet printhead and the ink droplet observer so that the first ink droplet appears in the field of view of the ink droplet observer, controlling the inkjet printhead to eject a second ink droplet from a terminal nozzle, moving the ink droplet observer and the inkjet printhead in the x and y directions so that the second ink droplet is clearly visible in the field of view of the ink droplet observer, accurately recording the x-direction movement distance Δx and the y-direction movement distance Δy of the ink droplet observer or the inkjet printhead, calculating the adjustment angle value of the ink droplet observer from Δx and Δy, and rotating the ink droplet observer clockwise or counterclockwise according to the angle value of the ink droplet observer, so that the single row of nozzle connection lines is perpendicular to the lens optical axis of the ink droplet observer. Compared with the prior art, the present invention has the advantages of simple calculation and high accuracy.

Description

[Technical field]

[0001] The present invention relates to precision ink jet printing applications, and more particularly to a method and system for aligning an ink drop spotter. [Background technology]

[0002] In precision applications of inkjet printing, it is necessary to know the volume of ink droplets ejected from each nozzle with a certain driving voltage waveform in order to facilitate optimization of the inkjet printing pattern, so it is necessary to detect the ink ejection status of each nozzle using an ink droplet observer before printing.

[0003] The physical size of the head is very large, and the size of each nozzle and the viewing range of the ink droplet observer are very large, so when detecting the state of a row of nozzles, the head or the ink droplet observer needs to be moved. If the position connecting line of each row of nozzles is not completely perpendicular to the ink droplet observer, the ink droplets ejected from the subsequent nozzles will exceed the depth of field range of the ink droplet observer when the head or the ink droplet observer is moved over a wide area. In addition, the orientation of the ink droplet observer is usually performed by observing an object of known length with the ink droplet observer, and then proportionally converting the actual length of the object using the corresponding relationship between the pixel distance in the viewing range of the ink droplet observer. However, if the position connecting line of each row of nozzles and the ink droplet observer are not completely perpendicular, there will be a certain error in the corresponding relationship, which will cause variations in the parameter values ​​such as the volume and velocity of the measured ink droplets.

[0004] Therefore, in order to ensure the accuracy of the measurement data of the ink droplet observer, it is necessary to calibrate the relative positions of the ink droplet observer and the head. Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE PRESENT EMBODIMENT In order to overcome the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a method for aligning an ink drop observer which is simple in calculation and has high calculation accuracy. [Means for solving the problem]

[0006] The object of the present invention can be achieved by the following technical solutions:

[0007] The method for aligning the ink drop spotter includes the following steps. Identifying the inkjet printhead to be detected; Controlling the ink jet print head to eject a first ink droplet from a starting nozzle; adjusting a relative position of the inkjet print head and the ink drop observer so that the first ink drop appears within a viewing range of the ink drop observer; controlling the ejection of a second ink droplet from a terminal nozzle of the inkjet print head; moving the ink drop observer and the ink jet print head in the x-direction and the y-direction so that the second ink drop is clearly visible within the observation field of the ink drop observer, and accurately recording the movement distance Δx in the x-direction and the movement distance Δy in the y-direction of the ink drop observer or the ink jet print head; Calculate the adjustment angle value of the ink drop observation device from Δx and Δy. According to the angle value of the ink droplet observer, the ink droplet observer is rotated clockwise or counterclockwise so that the single row of nozzle connection lines is perpendicular to the lens optical axis of the ink droplet observer.

[0008] The numerical range of Δx and Δy is a positive number, a negative number, or zero.

[0009] The calculation formula for the adjustment angle value of the ink droplet observer is:

number

[0010] When the adjustment angle value of the ink droplet observer is greater than 0, the ink droplet observer is rotated clockwise, and when the adjustment angle value of the ink droplet observer is less than 0, the ink droplet observer is rotated counterclockwise.

[0011] Moving the ink drop detector and the inkjet printhead can be one of two, or both at the same time, and only one of the two can be moved in the same direction.

[0012] The ink drop spotter alignment system includes: a host computer that executes the steps of: sending print data to a print controller; controlling and adjusting the relative positions of the inkjet print head and the ink droplet observer so that the first ink droplet appears in the field of view of the ink droplet observer; controlling the ink droplet observer and the inkjet print head to move in the x and y directions so that the second ink droplet appears clearly in the field of view of the ink droplet observer; accurately recording the moving distance Δx of the ink droplet observer or the inkjet print head in the x direction and the moving distance Δy of the ink droplet observer in the y direction; calculating an adjustment angle value of the ink droplet observer from Δx and Δy; and controlling the ink droplet observer to rotate clockwise or counterclockwise according to the adjustment angle value of the ink droplet observer so that the single row of nozzle connection line is perpendicular to the lens optical axis of the ink droplet observer; a print controller that drives the ink jet print head to eject ink and transmits a print drive signal to the ink drop observer; an inkjet printhead that controls a leading nozzle to eject a first ink droplet and a trailing nozzle to eject a second ink droplet in accordance with a print controller; and an ink droplet observer that synchronously captures the ink droplets being ejected in accordance with the print drive signal.

[0013] The numerical range of Δx and Δy is a positive number, a negative number, or zero.

[0014] The calculation formula for the adjustment angle value of the ink droplet observer is:

number

[0015] When the adjustment angle value of the ink droplet observer is greater than 0, the host computer controls the ink droplet observer to rotate clockwise, and when the adjustment angle value of the ink droplet observer is less than 0, the host computer controls the ink droplet observer to rotate counterclockwise.

[0016] The host computer controls the ink drop detector, the inkjet printhead to move in the x and y directions, either moving one of the two, or moving both simultaneously, and only moving one of the two in the same direction. Effect of the Invention

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) In the present invention, the angle adjustment value of the corresponding ink drop observer can be obtained by simply performing a trigonometric calculation, and the calculation method is simple and the amount of calculation is small.

[0019] (2) In the present invention, since only one of the ink droplet observer and the inkjet print head is adjusted in one direction, not only is the adjustment method simple, but the calculation can also be simplified.

[0020] (3) After aligning the ink droplet observer using the method of the present invention, there is no need to move the ink droplet observer or the inkjet print head to adjust the focus when automatically detecting a single row of nozzles. This enables rapid automatic detection of ink droplets being ejected from a single row of nozzles, improving detection efficiency. [Brief description of the drawings]

[0021] [Figure 1] 1 is a flow chart of a method of the present invention. [Diagram 2] FIG. 1 is a schematic diagram of an ink drop observation system. [Diagram 3] FIG. 13 is a schematic diagram of a detection process for a single row nozzle hole. [Figure 4] 11 is a schematic diagram showing a misalignment between a nozzle position connection line and a lens optical axis of an ink droplet observation device. FIG. [Diagram 5] 1A and 1B are schematic diagrams of a method for adjusting the position of an ink droplet observer, in which (a) is a schematic diagram of adjusting the position of an ink droplet ejected from a start nozzle, and (b) is a schematic diagram of adjusting the position of an ink droplet ejected from a terminal nozzle. [Figure 6] FIG. 1 is a schematic diagram of angle calculation of the alignment method of the ink drop observer of the first embodiment. [Figure 7] FIG. 11 is a schematic diagram of angle calculation of the alignment method of the ink drop observer of the second embodiment. [Figure 8] FIG. 13 is a schematic diagram of angle calculation of the alignment method of the ink drop observer of the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The present invention will be described in detail below with reference to the drawings and specific examples. The examples are implemented based on the technical solutions of the present invention, and provide detailed embodiments and specific operation procedures, but the protection scope of the present invention is not limited to the following examples.

[0023] The present invention relates to an ink drop monitor for automatically detecting nozzle status in ink jet printing. vessel As shown in FIG. 2, a typical ink drop observation system includes a host computer 110 and Print The host computer 110 includes a controller 120, an inkjet printhead 130, and an ink drop observer 140. Print The host computer 110 controls the ink droplet observer 140 to measure and analyze the characteristics of the image information of the ejected ink droplets 150. At the same time, the print controller 120 sends a print driving signal to the ink droplet observer 140, which then synchronously captures the ejected ink droplets 150 based on the print driving signal.

[0024] In a high-definition inkjet printing application scene, it is necessary to obtain characteristic information such as the volume, speed, and ejection angle of ink droplets ejected from each nozzle in order to further optimize and control the inkjet printing process. To improve detection efficiency, automatic detection is usually performed for each nozzle row of the head. As shown in FIG. 3, the ink droplet observer 140 first measures an ink droplet 1501 ejected from a nozzle 1601 at the start end of the inkjet print head 130. The inkjet print head 130 (or the ink droplet observer 140) is moved in the x direction, an ink droplet 1502 ejected from a nozzle 1602 is measured, and the inkjet print head 130 (or the ink droplet observer 140) is continued to be moved in the x direction, and ink droplets ejected from each nozzle are sequentially detected until an ink droplet 1520 ejected from the nozzle 1620 at the end is detected.

[0025] Due to an installation error between the inkjet print head and the ink droplet observation device, or due to the uneven distribution of the nozzles themselves in the inkjet print head, the single row of nozzle connection lines 260 and the lens optical axis 240 of the ink droplet observation device are not perpendicular to each other, as shown in FIG. 4. In order to adjust the relative positions of the inkjet print head 130 and the ink droplet observation device 140 and first detect the ink droplets ejected from the nozzle No. 1601 at the nozzle start end of the 160th row, and then detect other nozzles in the 160th row, for example, nozzle 1620, it is necessary to move the inkjet print head 130 or the ink droplet observation device 140 in the x direction. If the nozzle connection lines 260 and the lens optical axis 240 of the ink droplet observation device are not perpendicular to each other, the image of the ink droplets ejected from the other nozzles in the 160th row will exceed the detection depth of field of the ink droplet observation device 140 due to the movement in the x direction, and therefore it is necessary to adjust the focus of the inkjet print head 130 or the ink droplet observation device 140 in the y direction. Therefore, if the nozzle connection line 260 and the lens optical axis 240 of the ink droplet observation device are not perpendicular to each other, in order to observe the ink droplets ejected from different nozzles, it is necessary to continuously adjust the position of the inkjet print head 130 or the ink droplet observation device 140, which increases the number of detection operations and reduces the detection efficiency.

[0026] Example 1

[0027] In one embodiment, the inkjet printhead moves in the x-direction and the inkdrop spotter moves in the y-direction, and the automatic detection of the nozzles in a single row is realized by a host computer controlling the movement of the inkjet printhead and the inkdrop spotter. Figure 5 is a schematic diagram of the alignment method of the inkdrop spotter. This embodiment includes the following steps: Identifying an inkjet printhead 130 to be detected; A first ink droplet 1501 is ejected from a starting nozzle 1601 of the inkjet print head 130. The relative positions of the inkjet print head 130 and the ink droplet observer 140 are adjusted so that the ink droplet 1501 ejected from the inkjet print head starting nozzle 1601 appears within the visual field range of the ink droplet observer, and the coordinates (xh, yh) of the inkjet print head 130 and the coordinates (xw, yw) of the ink droplet observer 140 at that time are recorded. controlling the ejection of a second ink droplet 1520 from a terminal nozzle 1620 of the inkjet printhead; The inkjet print head 130 is moved in the x direction so that the ink droplets 1520 ejected from the nozzles 1620 at the ends of the inkjet print head 130 are positioned within the visual field of the ink droplet observer 140, and the position of the ink droplet observer is adjusted in the y direction so that the ink droplets 1520 are clearly visible within the visual field of observation. The coordinates (xh', yh) of the inkjet print head and the coordinates (xw, yw') of the ink droplet observer at that time are recorded. A triangle is created with the three vertices (xh, yh), (xh', yh), and (xh', yw'). As shown in FIG. 6, the lengths Δx and Δy of the right angles of the triangle are the x-direction movement distance of the inkjet print head 130 and the y-direction movement distance of the ink droplet observer 140. The angle θ to be adjusted by the ink droplet observer 140 can be calculated from the values ​​of Δx and Δy. The ink droplet observer is rotated according to the angle value θ, and when the angle value is greater than 0, the ink droplet observer is rotated clockwise, and when the angle value is less than 0, the ink droplet observer is rotated counterclockwise. This makes the single row of nozzle connection lines perpendicular to the lens optical axis of the ink droplet observer, so that there is no need to move the ink droplet observer or the inkjet print head to adjust the focus when automatically detecting the single row of nozzles, and it is possible to realize rapid automatic detection of ink droplets ejected from the single row of nozzles.

[0028] Example 2

[0029] In another embodiment, the inkjet print head moves in the x and y directions, the ink drop spotter does not move, and automatic detection of a single row of nozzles is achieved by a host computer controlling the movement of the inkjet print head. This embodiment includes the following steps: Identifying an inkjet printhead 130 to be detected; A first ink droplet 1501 is ejected from a starting nozzle 1601 of the inkjet print head 130. The relative position of the inkjet print head 130 and the ink drop observer 140 is adjusted so that the ink drop 1501 ejected from the inkjet print head starting nozzle 1601 appears within the visual field of the ink drop observer, and the coordinates (xh, yh) of the inkjet print head 130 at that time are recorded. controlling the ejection of a second ink droplet 1520 from a terminal nozzle 1620 of the inkjet printhead; The inkjet print head 130 is moved in the x direction so that the ink droplet 1520 ejected from the nozzle 1620 at the end of the inkjet print head 130 is positioned within the field of view of the ink droplet observer 140, and the coordinates (xh', yh) of the inkjet print head at that time are recorded. The position of the inkjet print head 130 is adjusted and moved in the y direction to focus so that the ink droplet 1520 is clearly visible within the observation field of view, and the coordinates (xh', yh') of the inkjet print head at that time are recorded. A triangle is created with the three points (xh, yh), (xh', yh), and (xh', yh') as vertices. As shown in FIG. 7, the lengths Δx and Δy of the right angles of the triangle are the movement distances of the inkjet print head 130 in the x and y directions, respectively. From the values ​​of Δx and Δy, the angle θ to be adjusted by the ink droplet observer 140 can be calculated. The ink droplet observer is rotated according to the angle value θ, and if the angle value is greater than 0, the ink droplet observer is rotated clockwise, and if the angle value is less than 0, the ink droplet observer is rotated counterclockwise so that the single row of nozzle connection lines is perpendicular to the lens optical axis of the ink droplet observer.

[0030] Example 3

[0031] In another embodiment, the ink drop spotter performs x-direction motion and y-direction motion, the ink jet print head does not move, and automatic detection of a single row of nozzles is achieved by a host computer controlling the ink drop spotter motion. This embodiment includes the following steps: Identifying an inkjet printhead 130 to be detected; A first ink droplet 1501 is ejected from a starting nozzle 1601 of the inkjet print head 130. The relative position of the inkjet print head 130 and the ink droplet observer 140 is adjusted so that the ink droplet 1501 ejected from the inkjet print head starting nozzle 1601 appears within the visual field range of the ink droplet observer, and the coordinates (xw, yw) of the ink droplet observer 140 at that time are recorded. controlling the ejection of a second ink droplet 1520 from a terminal nozzle 1620 of the inkjet printhead; The ink droplet observer 140 is moved in the x direction so that the ink droplet 1520 ejected from the nozzle 1620 at the end of the inkjet print head 130 is positioned within the field of view of the ink droplet observer 140, and the coordinates (xw', yw) of the ink droplet observer at that time are recorded. The position of the ink droplet observer 140 is adjusted in the y direction to focus so that the ink droplet 1520 is clearly visible within the observation field of view, and the coordinates (xw', yw') of the ink droplet observer at that time are recorded. A triangle is created with the three points (xw, yw), (xw', yw), and (xw', yw') as vertices. As shown in FIG. 8, the lengths Δx and Δy of the right angles of the triangle are the moving distances of the ink droplet observer 140 in the x and y directions, respectively. The angle θ to be adjusted by the ink droplet observer 140 can be calculated from the values ​​of Δx and Δy. The ink droplet observer is rotated according to the angle value θ, and if the angle value is greater than 0, the ink droplet observer is rotated clockwise, and if the angle value is less than 0, the ink droplet observer is rotated counterclockwise so that the single row of nozzle connection lines is perpendicular to the lens optical axis of the ink droplet observer.

[0032] The above is a detailed description of the preferred specific embodiments of the present invention. It should be understood that those skilled in the art can make many modifications and variations based on the idea of ​​the present invention without creative work. Therefore, the technical solutions that those skilled in the art can obtain based on the idea of ​​the present invention through logical analysis, reasoning, or limited experiments based on the prior art shall be within the scope of protection defined by the claims.

Claims

1. Identifying the inkjet printhead to be detected; Controlling the ejection of a first ink droplet from a starting nozzle of the inkjet print head; adjusting a relative position of the inkjet printhead and the ink drop observer so that the first ink drop appears within a viewing range of the ink drop observer; controlling the ejection of a second ink droplet from a distal nozzle of the inkjet printhead; moving the ink drop observer and the ink jet print head in the x-direction and the y-direction so that the second ink drop is clearly visible within the observation field of the ink drop observer, and accurately recording the movement distance Δx in the x-direction and the movement distance Δy in the y-direction of the ink drop observer or the ink jet print head; Calculate the adjustment angle value of the ink droplet observation device from Δx and Δy; A method for aligning an ink drop observer, comprising a step of rotating the ink drop observer clockwise or counterclockwise according to an angle value of the ink drop observer so that a single row of nozzle connection lines is perpendicular to a lens optical axis of the ink drop observer.

2. 2. The method of claim 1, wherein the numerical range of .DELTA.x and .DELTA.y is a positive number, a negative number, or zero.

3. The calculation formula for the adjustment angle value of the ink droplet observer is: [0010] and 2. The method for aligning an ink droplet observer according to claim 1, wherein .theta. is an adjustment angle value of the ink droplet observer.

4. The method for aligning an ink droplet observer according to claim 1, characterized in that, when the adjustment angle value of the ink droplet observer is greater than 0, the ink droplet observer is rotated clockwise, and when the adjustment angle value of the ink droplet observer is less than 0, the ink droplet observer is rotated counterclockwise.

5. 2. The method for aligning an ink droplet observer according to claim 1, wherein moving the ink droplet observer and the inkjet print head is moving one of the two or moving both simultaneously, and only one of the two is moving in the same direction.

6. A host computer executes the steps of: sending print data to a print controller; controlling and adjusting the relative positions of the inkjet print head and the ink droplet observer so that the first ink droplet appears in the visual field of the ink droplet observer; controlling the ink droplet observer and the inkjet print head to move in the x and y directions so that the second ink droplet appears clearly in the visual field of the ink droplet observer; accurately recording the x-direction movement distance Δx and the y-direction movement distance Δy of the ink droplet observer or the inkjet print head; calculating an adjustment angle value of the ink droplet observer from Δx and Δy; and controlling the ink droplet observer to rotate clockwise or counterclockwise based on the adjustment angle value of the ink droplet observer so that the single row of nozzle connection line is perpendicular to the lens optical axis of the ink droplet observer; a print controller that drives the ink jet print head to eject ink and transmits a print drive signal to the ink drop observer; an inkjet printhead that controls a leading nozzle to eject a first ink droplet and a trailing nozzle to eject a second ink droplet in accordance with a print controller; and an ink droplet observer that synchronously captures ink droplets ejected in accordance with a print drive signal.

7. 7. The ink drop observer alignment system of claim 6, wherein the numerical range of .DELTA.x and .DELTA.y is positive, negative, or zero.

8. The calculation formula for the adjustment angle value of the ink droplet observer is: [0025] and 7. The ink drop observer alignment system of claim 6, wherein .theta. is an angle adjustment value of the ink drop observer.

9. The ink droplet observer alignment system according to claim 6, characterized in that when the adjustment angle value of the ink droplet observer is greater than 0, the host computer controls the ink droplet observer to rotate clockwise, and when the adjustment angle value of the ink droplet observer is less than 0, the host computer controls the ink droplet observer to rotate counterclockwise.

10. 7. The ink drop observer alignment system of claim 6, wherein the host computer controls the ink drop observer and the ink jet print head to move in the x and y directions by moving one of the two, or by moving both simultaneously, and by moving only one of the two in the same direction.

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