CN116373459A - Nozzle printing deviation calibration method of ink-jet printer - Google Patents

Abstract

The invention relates to a nozzle printing deviation calibration method of an ink-jet printer, which comprises the following steps: printing out a printing page for calibration by using an ink-jet printer; scanning and preprocessing a printing page for calibration to obtain a printing page image; calculating to obtain an included angle in the horizontal direction and an offset angle in the longitudinal direction of the image; calculating the deviation amounts of all groups of lines in each line, mapping the deviation angle in the longitudinal direction into the deviation amount corresponding to the lines arranged longitudinally, and mapping the included angle in the horizontal direction of the image into the deviation amount corresponding to the lines arranged transversely to obtain the final deviation amount of each group of lines; and finally, carrying out optimal solution calculation on the final deviation amount of each line, namely taking the optimal solution as the error deviation amount in each printing mode, and compensating the error deviation amount in each printing mode into the printing of the ink-jet printer. The method ensures that the printing of the printer in different directions and speeds realizes the consistency in control, and improves the printing quality of the image.

Description

A method for calibrating nozzle printing deviation of an inkjet printer

technical field

The invention relates to the technical field of inkjet printing, in particular to a method for calibrating printing deviation of a nozzle of an inkjet printer.

Background technique

Inkjet printing technology is a technology that sprays ink droplets onto a printing medium through a nozzle to obtain images or text. The number of nozzle holes of a single nozzle is fixed, so the height and width of the image printed by each nozzle scan are limited, and if you want to obtain an image with a larger height efficiently and quickly, you need to splice the nozzles in the vertical direction, and the printing process Make the printing medium move forward or the inkjet car move forward to feed the paper. However, due to the inaccuracy of the installation due to the difference in the size of the nozzle itself, there is an alignment error between the splicing nozzles. When there is an alignment error in the nozzle, it will seriously affect the quality of the printed product; and at different speeds and directions, due to the tolerance of the printer mechanism It leads to the problem that the printed portraits cannot be aligned under different printings.

Therefore, need further improvement to prior art.

Contents of the invention

The technical problem to be solved by the present invention is to provide a printing offset calibration method of an inkjet printer capable of improving printing quality in view of the above prior art.

The technical scheme adopted by the present invention to solve the above-mentioned technical problems is: a method for calibrating print head printing deviation of an inkjet printer, which is characterized in that it includes the following steps:

Step 1. Use an inkjet printer to print out the printed page for calibration;

The data printed on the above calibration printout includes:

Line data, including lines set at intervals of m rows and n columns; both m and n are positive integers, and the row direction is horizontal, and the column direction is vertical; at least one row of lines is horizontally set, and at least one line is vertically set line;

Auxiliary positioning data, including auxiliary positioning lines arranged horizontally along the printed page and second positioning blocks arranged vertically along the printed page;

Step 2, scanning the printed page used for calibration in step 1, and preprocessing the scanned image to obtain the printed page image;

Step 3, arbitrarily select a plurality of points on the auxiliary positioning line of the printed page image, and calculate the deviation of the ordinate mode coordinate difference of each point on the auxiliary positioning line relative to the abscissa coordinate, and obtain the included angle in the horizontal direction of the image;

Step 4, according to the edge point coordinates of the second positioning block on the printed page image, calculate the offset angle on the image longitudinal direction; The offset angle above is mapped to the offset corresponding to the vertically set lines to obtain the final offset of the vertically set lines; in addition, the included angle in the horizontal direction of the image is mapped to the offset corresponding to the horizontally set lines to obtain The final deviation of the lines set horizontally;

Step 6. Finding the optimal solution for the final deviation of n groups of lines in each row of lines to obtain the optimal solution of the deviation in each row of lines;

Step 7. Taking the optimal solution of the deviation in each line as the error deviation in the printing mode corresponding to each line, and compensating the error deviation in each printing mode to the printing of the inkjet printer.

In order to realize the calibration of different printing modes, the line data in the step 1 at least corresponds to printing when the inkjet printer is in one or more of the following printing modes;

The printing modes of inkjet printers are: same direction and same speed, same direction and different speed, different direction and different speed, and different direction and different speed For the same color and different colors.

Preferably, the method for calculating the deviation corresponding to the longitudinal line data printed in the same direction in the step 5 is: taking the deviation on the same side as the deviation of each group of lines.

Preferably, the calculation method of the deviation corresponding to the longitudinal line data printed in the opposite direction in the step 5 is: taking the deviation of the center line as the deviation of each group of lines.

Preferably, the method for calculating the deviation corresponding to the horizontal line data in step 5 is: taking the deviation of the center line as the deviation of each group of lines.

Further, in the step 6, the specific steps for obtaining the optimal solution for the final deviation of n groups of lines in any row of lines are:

Step 6-1, counting the deviation mode of the n groups of lines in the current row of lines, and obtaining the deviation with the largest number of occurrences, which is recorded as the first optimal solution;

Step 6-2, find the group with the smallest deviation in the current line, and record the value with the smallest deviation as the second optimal solution;

Step 6-3. Comparing the first optimal solution with the second optimal solution to obtain the optimal solution of the deviation in the current line:

The specific comparison process is:

If the first optimal solution and the second optimal solution are the same, the first optimal solution or the second optimal solution is the optimal solution for the deviation in the current line;

If the number of line groups corresponding to the first optimal solution is within 1 group of the number of line groups corresponding to the second optimal solution, then the first optimal solution is taken as the optimal deviation in the current line untie;

If the number of line groups corresponding to the first optimal solution has lines that differ from the number of line groups corresponding to the second optimal solution within 2 groups, then the average of the first optimal solution and the second optimal solution is taken as The optimal solution for the deviation in the current line;

If the number of line groups corresponding to the first optimal solution does not have a line that differs from the number of line groups corresponding to the second optimal solution within 2 groups, then the second optimal solution is taken as the current line with the largest deviation Excellent solution.

In order to further improve the accuracy of deviation calibration, the step 6 also includes correcting the optimal solution of the deviation amount corresponding to the multi-row lines in the same direction and different speed printing mode. The specific correction steps are: judging Whether the optimal solution of the deviation of the multi-line lines has the same linear relationship as the speed, if yes, no correction is needed; correct.

In order to prevent the impact of other similar wrong line portraits on line calculation and to speed up the calculation time of data calculation, the auxiliary positioning data also includes m first positioning blocks arranged vertically along the printed page and arranged at intervals in sequence, each first positioning block Corresponding to a line in the line, used to position each line.

Compared with the prior art, the present invention has the advantages of: using the inkjet printer to print out the printed page for calibration, and by scanning the printed page, and calculating the deviation of each group of lines, the tolerances of each speed and direction are transmitted It can be connected to the printer control terminal to realize the calibration of the direction and speed of the printer nozzle, so that the printing of the printer in different directions and speeds can achieve control consistency, improve the quality of image printing, and achieve the purpose of nozzle calibration.

Description of drawings

1 is a schematic diagram of a printed page for calibration in an embodiment of the present invention;

Fig. 2 is a schematic diagram of a group of lines printed in the same direction in the embodiment of the present invention;

Fig. 3 is a schematic diagram of a group of lines printed in the opposite direction in the embodiment of the present invention;

Fig. 4 is a schematic diagram of a group of lines printed horizontally in the embodiment of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

The nozzle printing offset calibration method of the inkjet printer in this embodiment includes the following steps:

Step 1. Use an inkjet printer to print out the printed page for calibration;

As shown in Figure 1, the data printed on the printed page for the above calibration includes:

Line data, including lines set at intervals of m rows and n columns; both m and n are positive integers, and the row direction is horizontal, and the column direction is vertical;

Auxiliary positioning data, including m first positioning blocks arranged at intervals along the vertical direction of the printed page, auxiliary positioning lines set along the horizontal direction of the printed page, and second positioning blocks set along the vertical direction of the printed page, each first positioning block corresponds to Be in a line of lines; wherein at least one line is a horizontal line, and at least one line is a vertical line; as shown in Figure 1, there are two second positioning blocks, which are respectively arranged at the top of the printed page at intervals. The second positioning block also plays a role in judging the paper direction of the image;

The line data in step 1 in this embodiment at least corresponds to printing when the inkjet printer is in one or more of the following printing modes;

The printing modes of inkjet printers are: same direction and same speed, same direction and different speed, different direction and different speed, and different direction and different speed There are two kinds of same color and different color;

Step 2, scanning the printed page used for calibration in step 1, and preprocessing the scanned image to obtain the printed page image;

Step 3, arbitrarily select a plurality of points on the auxiliary positioning line of the printed page image, and calculate the deviation of the ordinate mode coordinate difference of each point on the auxiliary positioning line relative to the abscissa coordinate, and obtain the included angle in the horizontal direction of the image;

In this embodiment, the included angle in the horizontal direction of the image is obtained in a linear manner;

Step 4, according to the edge point coordinates of the second positioning block on the printed page image, calculate the offset angle in the longitudinal direction of the image;

The calculation method of the offset angle in this embodiment can be obtained by using the regression line equation generated by the edge point coordinates of the second positioning block;

Step 5, respectively calculating the deviation of n groups of lines in each row of lines, and mapping the deviation angle in the longitudinal direction of the image to the deviation corresponding to the vertically set lines to obtain the final deviation of the vertically set lines; In addition, the included angle in the horizontal direction of the image is mapped to the deviation corresponding to the horizontally set lines to obtain the final deviation of the horizontally set lines;

In this embodiment, since the printing direction will affect the splashing of the ink droplet, the splashing of the ink droplet cannot be controlled by humans, and is affected by the printing speed, and it is randomly generated. Therefore, each set of line data often has good data on one side and poor data on the other side. As shown in Figure 2, it is a group of lines printed in the same direction (this group of lines corresponds to one of the 13 groups of lines in each line in Figure 1), and the upper and lower sides of the lines are not aligned. For such scenarios, In step 5, the calculation method for the deviation corresponding to the vertical line data printed in the same direction is as follows: take the deviation on the same side as the deviation of each group of lines; as shown in Figure 3, for the deviation corresponding to the vertical line data printed in different directions The calculation method of the amount is: take the deviation of the center line as the deviation of each group of lines; The deviation of the line is taken as the deviation of each group of lines;

For each row of lines, since the printing method is the same, use the same deviation calculation method to calculate the deviation of n groups of lines in each line, and then map the offset angle in the longitudinal direction of the image to the deviation corresponding to the vertically set lines In the amount, thereby reducing the error of the calculated deviation in the horizontal direction; and mapping the angle in the horizontal direction of the image to the deviation corresponding to the line set horizontally, thereby reducing the error of the calculated deviation in the vertical direction;

In theory, the optimal solution for the deviation of each group of lines in each line should be the same, but due to external factors (missing line portraits, severe ink splashes, etc.), the optimal solution often fluctuates, so it is necessary to Find the optimal solution for the deviation;

Step 6. Find the optimal solution for the final deviation of the n groups of lines in each line, and obtain the optimal solution of the deviation in each line; that is, eliminate the error between different printings in the current printing mode;

Specifically:

The specific steps for obtaining the optimal solution for the final deviation of n groups of lines in any line of lines are:

Step 6-1, counting the deviation mode of the n groups of lines in the current row of lines, and obtaining the deviation with the largest number of occurrences, which is recorded as the first optimal solution;

Step 6-2, find the group with the smallest deviation in the current line, and record the value with the smallest deviation as the second optimal solution;

Step 6-3. Comparing the first optimal solution with the second optimal solution to obtain the optimal solution of the deviation in the current line:

The specific comparison process is:

If the first optimal solution and the second optimal solution are the same, the first optimal solution or the second optimal solution is the optimal solution for the deviation in the current line;

If the number of line groups corresponding to the first optimal solution is within 1 group of the number of line groups corresponding to the second optimal solution, then the first optimal solution is taken as the optimal deviation in the current line untie;

If the number of line groups corresponding to the first optimal solution has lines that differ from the number of line groups corresponding to the second optimal solution within 2 groups, then the average of the first optimal solution and the second optimal solution is taken as The optimal solution for the deviation in the current line;

If the number of line groups corresponding to the first optimal solution does not have a line that differs from the number of line groups corresponding to the second optimal solution within 2 groups, then the second optimal solution is taken as the current line with the largest deviation Excellent solution;

This step also includes correcting the optimal solution of the deviation amount corresponding to the multi-row lines in the same-direction and different-speed printing mode. Whether the solution has the same linear relationship as the speed, if yes, no correction is required; if not, the optimal solution of the deviation of each line is corrected according to the linear relationship between the speeds of each line;

Step 7. Taking the optimal solution of the deviation in each line as the error deviation in the printing mode corresponding to each line, and compensating the error deviation in each printing mode to the printing of the inkjet printer.

When the inkjet printer prints in the corresponding mode, the deviation of each group is compensated in the printing, so as to improve the image printing quality and achieve the purpose of nozzle calibration.

For special cases, there is a non-optimal solution setting: that is, the target optimal solution does not have an offset of 0. Therefore, use the design form input from an external file to input the specified optimal solution offset to meet the non-optimal solution in the production process. When searching for the optimal solution, the specified offset of the optimal solution search can be modified in real time (the default offset is 0).

Compared with manual input calibration, the calibration in the present invention greatly reduces user operations, reduces the complexity of operations, and can increase various calibration data and calibration requirements as required; for other calibration methods on the market, this method is due to adding the most The multiple calculations of the optimal solution and the linear calculation method between each group make this method have lower requirements on the printing quality of the nozzle than other methods, and reduce the hardware requirements for printer printing while ensuring accuracy. And the calibration operation can also be completed in the scene where the portrait is missing to a certain extent.

Claims (8)

1. A method for calibrating printing deviation of a nozzle of an ink-jet printer is characterized by comprising the following steps:

step 1, printing out a printing page for calibration by using an ink-jet printer;

the data printed by the printing page for calibration comprises:

the line data comprises m lines and n columns which are arranged at intervals; m and n are positive integers, the row direction is transverse, and the column direction is longitudinal; at least one line of lines is a line which is transversely arranged, and at least one line of lines is a line which is longitudinally arranged;

auxiliary positioning data comprising auxiliary positioning lines transversely arranged along the printing page and second positioning blocks longitudinally arranged along the printing page;

step 2, scanning the printing page for calibration in the step 1, and preprocessing the scanned image to obtain a printing page image;

step 3, randomly selecting a plurality of points on the auxiliary positioning lines of the printed page image, and calculating the deviation amount of the mode coordinate difference of the ordinate of each point on the auxiliary positioning lines relative to the abscissa to obtain an included angle in the horizontal direction of the image;

step 4, calculating to obtain an offset angle in the longitudinal direction of the image according to the edge point coordinates of the second positioning block on the printed page image; step 5, respectively calculating the deviation amounts of n groups of lines in each line of lines, and mapping the deviation angle in the longitudinal direction of the image into the deviation amount corresponding to the lines longitudinally arranged to obtain the final deviation amount of the lines longitudinally arranged; in addition, the included angle of the horizontal direction of the image is mapped into the deviation amount corresponding to the transversely arranged lines, so that the final deviation amount of the transversely arranged lines is obtained;

step 6, carrying out optimal solution calculation on the final deviation values of n groups of lines in each line to obtain an optimal solution of the deviation values in each line;

and 7, taking the optimal deviation value in each line as the error deviation value of each line corresponding to the printing mode, and compensating the error deviation value of each printing mode into the printing of the ink-jet printer.

2. The inkjet printer head printing deviation calibration method according to claim 1, wherein: the line data in the step 1 are at least printed when the ink-jet printer is in one or more of the following printing modes;

the printing mode of the ink-jet printer is as follows: the same direction and speed, different direction and speed, and same direction and speed, different direction and speed, same speed and different speed, different direction and speed, different color, and different color.

3. The inkjet printer head printing deviation calibration method according to claim 2, wherein: the deviation amount calculating method corresponding to the longitudinal line data printed in the same direction in the step 5 is as follows: the deviation on the same side is taken as the deviation amount of each group of lines.

4. A head print deviation calibration method of an inkjet printer according to claim 3, wherein: the deviation amount calculating method corresponding to the longitudinal line data printed in the different directions in the step 5 is as follows: the deviation of the center line is taken as the deviation amount of each group of lines.

5. The inkjet printer head printing deviation calibration method according to claim 4, wherein: the deviation amount calculating method corresponding to the transverse line data in the step 5 is as follows: the deviation of the center line is taken as the deviation amount of each group of lines.

6. The inkjet printer head printing deviation calibration method according to claim 5, wherein: in the step 6, the specific step of performing optimal solution to the final deviation value of n groups of lines in any line is as follows:

step 6-1, counting the deviation values of n groups of lines in the current line to obtain the deviation value with the largest occurrence number, and marking the deviation value as a first optimal solution;

step 6-2, searching a group with the smallest deviation in the current line, and marking the value with the smallest deviation as a second optimal solution;

step 6-3, comparing the first optimal solution with the second optimal solution to obtain an optimal solution of the deviation amount in the current line:

the specific comparison process is as follows:

if the first optimal solution and the second optimal solution are the same, the first optimal solution or the second optimal solution is used as an offset optimal solution in the current line;

if the number of the line groups corresponding to the first optimal solution has lines with the difference of 1 group from the number of the line groups corresponding to the second optimal solution, taking the first optimal solution as an offset optimal solution in the current line;

if the number of the line groups corresponding to the first optimal solution has lines with the difference of 2 groups from the number of the line groups corresponding to the second optimal solution, taking the average value of the first optimal solution and the second optimal solution as the deviation amount optimal solution in the current line;

if the number of the line groups corresponding to the first optimal solution does not have the lines with the difference of 2 groups from the number of the line groups corresponding to the second optimal solution, the second optimal solution is taken as the deviation optimal solution in the current line.

7. The inkjet printer head printing deviation calibration method according to claim 6, wherein: the step 6 further includes correcting the deviation amount optimal solution corresponding to the lines of the plurality of lines in the same direction and different speed printing mode, and the specific correction steps are as follows: judging whether the optimal solution of the deviation amount of the multi-line in the same-direction different-speed printing mode has the same linear relation with the speed, if so, correcting is not needed; if not, correcting the deviation amount optimal solution of each line according to the linear relation of the speeds among the lines.

8. The inkjet printer head printing deviation calibration method according to any one of claims 1 to 7, wherein: the auxiliary positioning data also comprises m first positioning blocks which are longitudinally arranged along the printing page and are sequentially arranged at intervals, and each first positioning block corresponds to one line which is positioned on the line and is used for positioning each line.

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