Method of optimizing print speed of a CIJ printer when printing 2D or graphic codes

Abstract

A method of optimizing the printing speed of a CIJ printer when printing 2D or graphic codes is disclosed, relating to a method of printing a graphic code on a surface, the graphic code having H rows and W columns and comprising a pattern of H x W cells, each cell being located at the intersection of a column and a row, each cell or dot being formed by means of a drop of ink generated by a print head of a continuous inkjet printer, two consecutive dots of the same column being separated by at least one non-printed cell, the method comprising, when printing each column: retrieving or selecting, from at least one set of data or database DB of the charge of the drops of ink for each of a plurality of configurations of drops of ink to be printed in a column, the charge to be applied to each drop of ink to print the dots of the column, the number being less than or equal to 2 if H is even (H / 2)+1 , or less than or equal to 2 ((H+1) / 2)+1 if H is odd; charging the drops of ink of the dots of the column to be printed and printing the column according to the charge retrieved or selected from the at least one set of data or database DB.

Description

Technical Field

[0001] This invention relates to a method and printer for printing ink droplets, particularly at high speed. Background Technology

[0002] Continuous inkjet (“CIJ”) printers are specifically designed for printing characters (letters and / or numbers and / or symbols) or encoded information (barcodes, QR codes, dot codes, etc.) on surfaces, especially on uneven surfaces such as cables, bottles, or cans.

[0003] like Figure 1A and Figure 1B As shown, CIJ printers typically use dot matrix printing mode to print characters such as... Figure 2 The characters shown. Figure 1A The image shows a string of ink droplets generated by the printer's generator, used for printing. Figure 1B The column of dots (or print droplets), this column is Figure 2 The first or last column of characters shown: the ink droplets fly toward the holder where the characters must be printed; Figure 2 The illustration shows printed characters composed of continuous printed segments or lines, each segment or line comprising multiple printed ink droplets, each droplet located at a specific pixel. In dot matrix mode, each column is processed independently of the others, and the corresponding droplet string comprises as many droplets as possible from the dots in a column. Some of these droplets are used for printing, while others may not be printed, and the droplet string also includes guard droplets. These columns are printed one after another.

[0004] Multiple protective droplets are inserted between charged droplets to reduce or minimize electrostatic interactions between them. These protective droplets are uncharged or have a low charge and collect in a reservoir, where the corresponding ink is recycled within the printer. In fact, charged droplets repel each other due to electrostatic interactions. The electrostatic force is inversely proportional to the square of the distance between the droplets; adding one or more protective droplets between two printed droplets increases the distance between the last few droplets, thus reducing the repulsive force.

[0005] Therefore, the number of ink droplets used to print an entire column is equal to the sum of the maximum number of ink droplets to print (the number of pixels in that column) and the number of guard droplets that separate the continuous charged ink droplets.

[0006] Reducing the number of protective ink droplets would allow for faster printing speeds, but would also reduce print quality. Therefore, due to strong electrostatic interactions, it is almost impossible to reduce the number of protective ink droplets.

[0007] One problem is finding a printing method to optimize printing speed without reducing the printing quality of printed characters (letters, numbers, etc.) or printed codes.

[0008] In particular, encoding information involving objects or surfaces, such as printing QR codes, or printing graphic codes such as data matrix codes or dot code symbols, requires faster printing speeds.

[0009] In some applications, flexibility is also required to adapt the size of the information to the surface that can be printed. Summary of the Invention

[0010] The present invention provides a first method for printing QR codes, symbols, or characters on a substrate surface, or printing graphic codes, symbols, characters, patterns, or graphics, such as data matrix codes or dot code symbols.

[0011] The code, symbol, character, pattern, or graphic is printed on the surface and has a height H (with H rows) and a width W (a series of W columns i (i = 1, ..., W)). It includes a square or rectangular cell pattern, with each printed cell or dot formed by ink droplets generated by the printhead of a continuous inkjet printer.

[0012] The method according to the invention for printing such graphic codes, symbols, characters, patterns, or graphics includes, when printing each column:

[0013] *From at least one set of data or database (DB) of droplet charges for each of multiple configurations of the droplets to be printed, retrieve or select the charge to be applied to each droplet for printing the column, wherein the number is less than or equal to 2 if H is even. (H / 2)+1 Or, if H is odd, then the quantity is less than or equal to 2. ((H+1) / 2)+1 ;

[0014] *The ink droplets used to print the column are charged according to the charge retrieved or selected from the at least one set of data or database (DB), and the column is printed.

[0015] In the specific case where any two consecutive points in each column of a graphic code (or symbol, character, pattern, or graphic) are separated by at least one unprinted cell:

[0016] -If H is even, then:

[0017] *A single set of data or a database (DB) of charges can be created, wherein the number of ink droplets to be printed in the set of data or database (DB) is equal to 2. (H / 2)+1 *Alternatively, two sets of data or databases (DBs) for the charge can be implemented (one set of data or databases (DBs) for even-numbered columns and another set of data or databases (DBs) for odd-numbered columns), wherein the number of ink droplets to be printed in each set of data or database (DB) is equal to 2.(H / 2) ;

[0018] -If H is odd, then:

[0019] *A single set of data or a database (DB) of charges can be created, wherein the number of ink droplets to be printed in the set of data or database (DB) is equal to 2. (H+1) / 2)+1 ;

[0020] * Alternatively, two sets of data or databases (DBs) of charge can be implemented, one set of data or databases (DBs) for multiple configurations of the ink droplets to be printed, and multiple configurations equal 2. ((H+1) / 2) Another set of data or database (DB) is used for multiple configurations of the ink droplets to be printed, where multiple configurations equal 2. (H-1 / 2) .

[0021] In each column of the code (or symbol, character, pattern, or graphic), not every position can be printed, but only every other position. For example, even positions can be printed in odd columns, and odd positions can be printed in even columns. In each column, two printed points are separated by at least one non-printed position. The printed symbols include even and odd columns, and each column i includes h. i One print point:

[0022] -If H is even, then h i ≤H / 2;

[0023] -If H is odd, then h i ≤(H+1) / 2.

[0024] Specifically, for each even column i and odd column i+1, a charge to be applied to each ink droplet is retrieved or selected from the at least one set of data or database (DB), the ink droplets are charged, and the even column i and odd column i+1 are printed respectively according to the charge retrieved or selected from the at least one set of data or database (DB), and the columns are printed.

[0025] In a specific embodiment, two sets of data or databases (DB1, DB2) are implemented. If H is even, each set of data or database provides ink droplet charges for multiple configurations of print points in a column, for use with the print points. If H is even, the multiple configurations are less than or equal to 2. (H / 2)+1 Or, if H is odd, then multiple configurations are less than or equal to 2. ((H+1) / 2)+1 One of the data sets or databases may provide the ink droplet charge for printing odd-numbered columns, and the other data set or database may provide the ink droplet charge for printing even-numbered columns.

[0026] The charge to be applied to the ink droplet to print dots in each odd column can be selected from the first set of data or database (DB1), and the charge to be applied to the ink droplet to print dots in each even column can be selected from the second set of data or database (DB2).

[0027] In a specific embodiment:

[0028] -The sum of H and W, H+W, is an odd number;

[0029] - and / or, even-numbered cells are printed only in odd-numbered columns, and odd-numbered cells are printed only in even-numbered columns;

[0030] - and / or, the plurality of ink droplets are charged and printed according to a dot matrix pattern.

[0031] The present invention also relates to a method for printing graphic codes (or symbols, characters, patterns, or graphics) on a surface, the method comprising:

[0032] - For each of multiple configurations of dots to be printed in a column, select at least one set of data or databases (DBs) of droplet charge, the number of which is less than or equal to 2. (H / 2)+1 H is an even number; or the quantity is less than or equal to 2. ((H+1) / 2)+1 H is an odd number;

[0033] - Define the height H and width W of the printed graphic code based on the at least one set of data or database (DB);

[0034] - A graphic code is printed using the first method described above according to the present invention. The graphic code has H rows and W columns i (i = 1, ... W) and includes a pattern consisting of H × W units, each unit being located at the intersection of a column and a row, and two consecutive points in the same column being separated by at least one unprinted unit.

[0035] The selection of at least one set of data or database (DB) may include:

[0036] - For multiple configurations of printable dots, select the first set of data or database (DB1) of droplet charge; if H is even, multiple configurations are less than or equal to 2. (H / 2) Or, if H is odd, then multiple configurations are less than or equal to 2. ((H+1) / 2) One configuration,

[0037] - For multiple configurations of printable dots, select the second set of data or database (DB2) of droplet charge; if H is even, multiple configurations are less than or equal to 2. (H / 2) Or, if H is odd, then multiple configurations are less than or equal to or less than 2. ((H+1) / 2) One configuration.

[0038] A specific embodiment of the first method according to the present invention further includes:

[0039] - Setting a reduced number of rows H', where if H is even, then H' < H / 2, and if H is odd, then H' < (H + 1) / 2;

[0040] - For each column n (1 ≤ n < W) of the symbol, in the nth column, in the first row to the H'th row or fewer rows, generating H' ink droplets and printing H' dots or fewer dots,

[0041] - If the nth column of the symbol has more than H' dots, or has multiple dots in the rows between row H' and row H, generating more ink droplets and printing the required number of dots in the column.

[0042] The relative speed of the print head of the continuous inkjet printer and the surface can be changed.

[0043] The present invention also provides a continuous inkjet printer for printing two-dimensional codes or symbols or characters, or printing graphic codes or symbols or characters or graphics.

[0044] The two-dimensional code or symbol or character, or graphic code or symbol or character or graphic (on the printing surface) has a height H and a width W, forming H rows and W columns i (i = 1,..., W), and includes a pattern composed of H × W cells, each cell can be located at the intersection of a column and a row, and the printer includes:

[0045] - Means for forming a plurality of ink droplets, for example, at least one ink droplet generator;

[0046] - A memory device storing at least a set of data or a database (DB) of ink droplet charges for each of a plurality of configurations of ink droplets to be printed in a column. If H is even, the number of configurations is less than or equal to 2 (H / 2)+1 , or if H is odd, the number of configurations is less than or equal to 2 ((H+1) / 2)+1 ;

[0047] - A controller programmed to retrieve or select, for each column, the charge to be applied to each ink droplet for printing the column from the at least one set of data or the database (DB);

[0048] - Means for charging the ink droplets for printing the column according to the charge, for example, at least one electrode;

[0049] - Means for deflecting the charged ink droplets (towards the printing surface), for example, at least one electrode.

[0050] In the continuous inkjet printer according to the present invention, the memory device can store:

[0051] *The first set of data or database provides a charge that is applied to the ink droplets for printing each of multiple configurations of ink droplets to be printed in an odd-numbered column, where the number is less than or equal to 2 if H is even. (H / 2) And if H is odd, the quantity is less than or equal to 2. ((H+1) / 2) ,

[0052] *The second set of data or database provides the charge, the charge to be applied, or each of the multiple configurations of ink droplets to be printed in the even-numbered columns, where the number is less than or equal to 2 if H is even. (H / 2) And if H is odd, then the quantity is less than or equal to 2. ((H+1) / 2) .

[0053] In a particular embodiment, the memory device may store:

[0054] - If H is even, then store:

[0055] *A separate set of data or a database (DB) of charges, wherein the number of ink droplets to be printed in the set of data or database (DB) is equal to 2. (H / 2)+1 ;

[0056] *Alternatively, two sets of data or databases (DBs) for the charge, for example, one set of data or databases (DBs) for even-numbered columns and another set of data or databases (DBs) for odd-numbered columns, wherein the number of ink droplets to be printed in each set of data or database (DB) is equal to 2. (H / 2) ;

[0057] - If H is odd, then store:

[0058] *A separate set of data or a database (DB) of charges, wherein the number of ink droplets to be printed in the set of data or database (DB) is equal to 2. (H+1) / 2)+1 ;

[0059] * Alternatively, two sets of data or databases (DBs) of charge, one set of data or databases (DBs) for multiple configurations of the ink droplets to be printed, the multiple configurations equaling 2. ((H+1) / 2) Another set of data or database (DB) is used for multiple configurations of the ink droplets to be printed, where multiple configurations equal 2. (H-1 / 2) .

[0060] The continuous inkjet printer according to the present invention may further include means for setting and / or storing a reduced number of rows H', where if H is even, H' < H / 2, and if H is odd, H' < (H + 1) / 2, and controlling the printer such that:

[0061] - For each column n (1 ≤ n < W) of the symbol, print H' ink droplets or fewer ink droplets in the column n.

[0062] - If the nth column of a symbol having more than H' dots or multiple dots in the rows between row H' and row H must be printed, print the required number of dots in the column.

[0063] The controller of the printer according to the present invention includes means for receiving a message or a graphic or a code or a symbol or a character to be printed and accordingly selecting appropriate charge data from one or more databases.

[0064] The present invention also provides a second method for printing a two-dimensional code or a symbol or a character, or a graphic code or a symbol or a character or a pattern or a graphic having a height of H and a width of W on a surface, the graphic code or the symbol or the character or the pattern or the graphic having H rows and W columns i (i = 1,..., W) and including a pattern composed of H × W cells, each cell being located at the intersection of a column and a row, and each printing unit or dot being formed by an ink droplet generated by a print head of a continuous inkjet printer, the method including:

[0065] - For example, set or select a reduced number of rows H' < H from a memory.

[0066] - For each column i (1 ≤ i < W), in the nth column, for example, in the first row to the H' -th row, generate H' ink droplets and print H' dots or fewer dots.

[0067] - If the ith column has more than H' printing dots, or has multiple printing dots in the rows between row H' and row H, generate more ink droplets and print the required number of dots in the column.

[0068] The setting or selection of the reduced number of rows H' < H can be performed:

[0069] - Before printing the first column of the graphic code or character, H' is constant for all columns of the graphic code or character.

[0070] - Alternatively, before printing any column of the graphic code or character, H' is different for at least two columns of the graphic code or character.

[0071] The symbol or character is a data matrix code, or a dot code symbol or letter, or a number, or a picture or any graphic symbol.

[0072] The present invention also relates to a continuous inkjet printer for printing two-dimensional codes or symbols or characters, or printing graphic codes or symbols or characters or patterns or graphics, the height of the two-dimensional code or symbol or character, or the graphic code or symbol or character or pattern or graphic (on the printing surface) being H and the width being W, the code or symbol or character or pattern having H rows and W columns i (i = 1,..., W), and including a pattern composed of H×W cells, each cell being located at the intersection of a column and a row, the printer comprising:

[0073] - means for generating ink droplets, for example, at least one ink droplet generator;

[0074] - means for selecting or setting a reduced height H'<H, for example, a controller;

[0075] - means for charging the ink droplets generated by the means for generating ink droplets, for example, at least one electrode;

[0076] - control means, for example, the above-mentioned controller, for:

[0077] * printing H' dots or fewer dots in at least one column of a character or graphic code, and then printing the next column using ink droplets starting from ink droplet H'+1 or ink droplet H'+2;

[0078] * if the column contains more than H' dots, printing the required number of dots in the column.

[0079] The means for setting or selecting a reduced number of rows H'<H can be programmed to:

[0080] - before printing the first column of a graphic code or character, H' being constant for all columns of the graphic code or character;

[0081] - or, before printing any column of the graphic code or character, H' being different for at least two columns of the graphic code or character.

[0082] The controller of the printer according to the present invention includes means for receiving a message or graphic or code or symbol or character to be printed and accordingly selecting a suitable number of charges from one or more databases.

[0083] In the continuous inkjet printer according to the present invention:

[0084] - the sum H+W of H and W is odd;

[0085] - and / or, the controller can be programmed such that the printer prints even cells only in odd columns and the printer prints odd cells only in even columns;

[0086] - and / or, the controller can be programmed to cause the plurality of ink droplets to print according to a dot matrix pattern.

[0087] - and / or, the number of ink droplets N1 generated <H。 Attached Figure Description

[0088] Figure 1A and Figure 1B This refers to the ink droplets generated by the CIJ printer for printing characters in a dot matrix pattern.

[0089] Figure 2 Indicates characters printed in dot matrix mode;

[0090] Figure 3A and Figure 3B Dot code symbol;

[0091] Figure 4A and Figure 4B This refers to a string of ink droplets for printing dot code symbols according to known methods and the present invention;

[0092] Figures 5A to 5D It is based on known methods ( Figure 5A ) and embodiments according to the present invention ( Figure 5B to Figure 5D Examples of printed characters;

[0093] Figure 6A This is a schematic diagram of the printhead of an offset continuous jet printer to which the present invention can be applied;

[0094] Figure 6B This represents the main unit of an inkjet printer to which the present invention can be applied;

[0095] Figure 7 This describes the structure of an inkjet printer to which the present invention can be applied. Detailed Implementation

[0096] According to embodiments of the present invention, a method for printing QR codes or graphic codes (e.g., data matrix codes) is disclosed. However, the present invention is also applicable to methods for printing two-dimensional symbols or characters, graphic codes or symbols or characters or patterns on a substrate surface.

[0097] A QR code or graphic code consists of black and white units arranged in a square or rectangular pattern of H×W units, with H rows and W columns. Each unit is located at the intersection of a column and a row, and each printed unit or dot is formed by generating ink droplets.

[0098] like Figure 3A and Figure 3B As shown, rows 1 to H can be drawn from one of the first sides of the pattern (e.g., Figure 3A or Figure 3B From the left side to the opposite side (e.g., the left-hand side) to the opposite side. Figure 3A or Figure 3B Counting can be done from the right-hand side of the pattern; columns 1 to W can be counted from a second side of the pattern perpendicular to the first side (e.g., the right-hand side); columns 1 to W can be counted from a second side of the pattern perpendicular to the first side (e.g., the right-hand side of the pattern). Figure 3A or Figure 3B From the lower side to the opposite side (e.g., Figure 3A or Figure 3B To count (for example, on the upper side) Figure 3A Above, the column numbers are 1-6);

[0099] In a specific instance of this invention, instead of printing every single position in each column of the code, it can only be printed every other position; for example:

[0100] - Print even positions only in odd columns

[0101] - Print odd columns only in even columns.

[0102] The code that is particularly useful in this application is called dot code, as disclosed in the IAM International Symbol Specification, Version 4.0 Dot Code, document number TSC1907001, approved by the committee on 19 July 2019.

[0103] An example of a specific printable QR code or graphic code according to the present invention is... Figure 3A and Figure 3B The dot code symbol shown. The dot code symbol has the following properties in particular:

[0104] - It has a rectangular shape and a height H( Figure 3A H1 and Figure 3B H2) and width W (W1 and W1 in Figure 3A) Figure 3B W2), H+W is an odd number, H is the number of rows, and W is the number of columns; the spacing between two consecutive rows is equal to Y, and the column spacing between two consecutive columns is equal to X;

[0105] - In each column, you can't print every single position; you can only print every other position. Typically, even-numbered positions are printed in odd-numbered columns, and odd-numbered positions are printed in even-numbered columns. This is in... Figure 3A As shown in the figure, even-numbered positions are printed in columns 1, 3, 5, etc., and odd-numbered positions are printed in columns 2, 4, 6, etc.

[0106] The symbol can only have two corner positions on a single edge, and these two corner positions are point positions (therefore, they can be printed), while the corners of opposite edges are not point positions and therefore will never be printed (e.g., in...). Figure 3A Above, the top corner is the location of a point, the bottom corner is not the location of a point; in Figure 3BAmong them, the left - hand corner is the dot position, and the right - hand corner is not the dot position).

[0107] Since the dot - code symbol is rectangular rather than square, the dot - code symbol has a unique property: the height (or number of rows) H and width (or number of columns) of the dot - code symbol can adapt to the surface available for the same information. For example, the same information is encoded using Figure 3A and Figure 3B dot - code symbols, although Figure 3A and Figure 3B dot - code symbols look completely different, especially having different heights H1 and H2 < H1. Other two - dimensional barcodes (e.g., data matrix codes or QR codes) do not provide this flexibility.

[0108] The first method according to the present invention is based on a limited number of ink droplets for printing each column of a two - dimensional barcode or a graphic code, the graphic code having a height H and a width W; in some cases, H + W is odd.

[0109] Figure 4A and Figure 4B show a column for printing the code according to the prior art and according to the present invention, especially a string of ink droplets for printing a dot - code symbol.

[0110] According to the prior art ( Figure 4A ), a number N0 of ink droplets are generated at the rate of a piezoelectric ink - droplet generator, where some of the ink droplets (shown in black in Figure 4A ) are used for printing on the substrate 800 (the number of these ink droplets for printing is less than or equal to H), and some ink droplets are protective ink droplets G. Thus, N0 is equal to H plus the number of protective ink droplets.

[0111] According to the present invention ( Figure 4B ), N1 ink droplets 24 (N1 < N0) (e.g., N1 / N0 = 0.5 or N1 / N0 # 0.5) are generated at the rate of a piezoelectric ink - droplet generator, where some of the ink droplets (shown in black in Figure 4B ) are used for printing on the substrate 800 (if H is even, the number of these ink droplets for printing is less than or equal to H / 2, or if H is odd, the number of these ink droplets for printing is less than or equal to (H + 1) / 2), and two consecutive ink droplets can be separated by a protective ink droplet. N1 < N0 because ink droplets are not used in non - printable positions. In addition, in order to print every other dot (or fewer dots) in each column of the symbol, the ink droplets are charged, the electrostatic interaction between consecutive charged ink droplets is less, and the need for including protective ink droplets is reduced. Thus, N1 is equal to H / 2 plus the number of protective ink droplets.

[0112] In one embodiment: H / 2 ≤ N1 < H.

[0113] Therefore, the printing speed of the method according to the present invention is higher than that of the method according to the prior art.

[0114] According to one aspect of the invention, at least a first set of data or a database can be created for the ink droplet charges of printing odd-numbered columns of dots, for example, for the ink droplet charges to be printed at even-numbered positions in the odd-numbered columns. The at least first set of data or a database includes N print points in any odd-numbered column. odd A list of configurations, and the required droplet charge for each of the stated configurations for the printed dots. For example, in Figure 3A The system identifies three configurations for odd-numbered sequences 1, 3, and 5. The number of configurations is N. even Less than or equal to:

[0115] - If H is even, then less than or equal to 2 (H / 2) One configuration;

[0116] - If H is odd, then less than or equal to 2 ((H+1) / 2) One configuration.

[0117] To create the first set of data or database, ink droplets 24 ( Figure 4B The position and / or charge of the ink droplets are changed to determine how best to protect the droplets from electrostatic interactions for printing columns 1, 3, 5, etc. of the graphic code. Therefore, the charge applied to the ink droplets 24 can be identified or measured to achieve high-quality printing. This can be done for each odd-numbered column of the graphic code (especially in the case of dotted code symbols), with each column having at most H / 2 (H is even) or (H+1) / 2 (H is odd) print dots. Protective ink droplets can be included in the generated droplet string. The number of protective ink droplets is less than... Figure 4A The method protects the number of ink droplets, based on Figure 4A In this method, H ink droplets are generated for each column (at the same printing speed, one ink droplet is used for every possible point in that column), so the ink droplets are closer to each other and have more electrostatic interaction.

[0118] At least a second set of data or a database can be created for the ink droplet charges to print dots in even-numbered columns. For example, at least a second set of data or a database can be created for the ink droplet charges to be printed at odd positions in the even-numbered columns. The at least second set of data or a database includes N print dots in any even-numbered column. even A list of configurations, and the required droplet charge for each of the stated configurations for the printed dots. For example, in Figure 3A The system identifies three configurations for even-numbered sequences 2, 4, and 6. The number of configurations is N. even Less than or equal to:

[0119] - If H is even, then less than or equal to 2 (H / 2) One configuration;

[0120] - If H is odd, then less than or equal to 2 ((H+1) / 2) One configuration.

[0121] To create a second set of data or a database, ink droplets 24 ( Figure 4B For columns 2, 4, 6, etc., used for printing graphic codes, the position and / or charge of the ink droplets can be varied to determine how best to protect the droplets from electrostatic interactions. Therefore, the charge applied to ink droplet 24 can be identified or measured to achieve high-quality printing. This can be done for each even-numbered column of the graphic code (especially in the case of dotted code symbols), with each column having at most H / 2 (H is even) or (H+1) / 2 (H is odd) dots. Protective ink droplets can be included in the generated droplet string. The number of protective ink droplets is less than... Figure 4A The method protects the number of ink droplets, based on Figure 4A In this method, H ink droplets are generated for each column, so the ink droplets are closer to each other and have more electrostatic interactions.

[0122] The first column is printed by retrieving or selecting the ink droplet charge required to print the first column from the first set of data or database; the second column is printed by retrieving or selecting the ink droplet charge required to print the second column from the second set of data or database; the third column is printed by retrieving or selecting the ink droplet charge required to print the third column from the first set of data or database, and so on.

[0123] Therefore, when alternating between printing columns of QR codes or graphic codes, the CIJ printer switches from one of the databases to the other.

[0124] According to the combination Figures 1A to 2 The dot matrix pattern is interpreted to perform printing.

[0125] In one variation, a separate set of data or database is created, comprising a list of N configurations of print points in any column of a two-dimensional or graphic code, and the ink droplet charge for printing any of the N configurations is given. N is:

[0126] - If H is even, then less than or equal to 2 (H / 2)+1 (=2×2 (H / 2) );

[0127] - If H is odd, then less than or equal to 2 (H+1 / 2)+1 (=2×2 (H+1 / 2) ).

[0128] For both odd and even columns, all configurations are contained within the separate set of data or database.

[0129] The size of each of the aforementioned data groups or databases (based on the number of configurations identified in the data group or database) is less than, for example: Figure 4A The figure shows the size of the data set or database that gives the charge for each column of higher number of ink droplets generated.

[0130] According to the database of the present invention, the charge to be applied to the maximum number of ink droplets ((H / 2)+1) or ((H+1) / 2)+1 is much smaller than H, and therefore more than H ink droplets (similar to) Figure 4A A database of charges for continuous ink droplets is easier to generate and implement: if H is even, the database includes up to 2 H / 2 One configuration or 2 (H / 2)+1 The database contains a maximum of 2 configured charge data; if H is odd, the database includes a maximum of 2 (H+1) / 2 One configuration or 2 ((H+1) / 2)+1 The database contains configurable charge data. It can be compared to data used for 2... H A configured database (which contains) Figure 4A The data from all ink droplets in a continuous stream can be searched more quickly. Furthermore, a smaller database contributes to better print quality (the database for a larger number of configurations includes data from a smaller database used to calculate interpolation).

[0131] Each of the databases can be stored in the memory of the CIJ printer's controller, which can retrieve or select charge data from each configured data set or database of the print point to be printed based on the message or message to be printed on the substrate.

[0132] The flexibility of dot notation provides some further advantages related to this invention, allowing the same information to be printed at variable heights (see [link]). Figure 3A and 3B ):

[0133] - If one or more databases with a row number equal to H' are available, the dot code symbol with row H' can be printed;

[0134] -If the number of rows is H k If k databases (k = 1, ..., n) are available, then one or two ("even" / "odd") databases with a specific number of rows H can also be selected. k0 Specific databases, H k0 This will be the number of rows of the printed graphic code. In other words, the number of rows of printed symbols can be adapted to the available database;

[0135] - If a specific height H of a given graphic code is given (e.g., because the surface to be printed is limited), one or two databases can be selected from multiple available databases or database pairs for different numbers of lines (if H is odd, the number of lines is (H + 1) / 2; if H is even, the number of lines is H / 2, H' (> (H + 1) / 2 or H / 2), H" (> (H + 1) / 2 or H / 2), etc.). Different numbers of lines mean different configurations.

[0136] Therefore, the printer's controller can select a suitable database each time a new graphic code is printed; if two databases ("even" / "odd") are selected, then whenever a new column (even or odd) of the two-dimensional or graphic code is to be printed, the printer's controller switches from one of the two databases to the other database.

[0137] Even when the relative speed between the print head of a continuous inkjet printer and the print surface 800 changes, especially if the speed varies within a certain speed range around the nominal speed V n e.g., within a range of 3 / 4V n and 4 / 3V n it is still possible to print graphic codes, such as dot code symbols, using the same database. Thus, the database according to the present invention provides additional flexibility.

[0138] Another method according to the present invention relates to two-dimensional codes or graphic codes, such as dot code symbols, but also to any other kind of characters (letters, in any known alphabet), numbers, pictures, or any other symbols (e.g.: &, %, etc.) or patterns or graphics or messages that have to be printed; examples of alphabetic characters are given below, but this other method is also applicable to any of the numbers, pictures, or symbols or patterns or graphics or messages mentioned above.

[0139] This other method is based on the consideration that rarely is a whole column of a pattern composed of multiple cells printed. For example, to print the letter "L", a whole column is printed, but all other columns have only one dot. Thus, many generated ink droplets are not used or printed.

[0140] According to this other method, just before printing a column or before printing, for example, a character (to print all columns of the character), a reduced number of lines H', H' < H, can be defined by the printer designer or selected by the operator. H' can be stored in the printer's memory and used by the controller when implementing another method according to the present invention.

[0141] By using a series or sequence of H' ink droplets (which may or may not participate in printing) to print any column n of a character or symbol of height H, the time required to print most columns of that character or symbol is greatly reduced. The printing of the next column n+1 begins with an ink droplet H'+1, H'+2, or H'+G (where G is the number of guard droplets between two columns) following the ink droplet H': therefore, a maximum of H' ink droplets are used to print column n.

[0142] If a particular column requires H1 ink droplets (for example, because the column has more than H1 dots), H>H1>H', then H1 ink droplets are used for that column, so the printing process is slightly slower, but still much faster than printing with H ink droplets per column.

[0143] In other words, the number of ink droplets (including printing droplets and non-printing droplets) used to print any column is limited to a number H', which is less than the maximum number H of dots in that column, unless printing a specific column requires more ink droplets (in which case more ink droplets are used).

[0144] For example, before printing the first column of the character, the controller can select the value of H', which is constant for all columns of the character.

[0145] Alternatively, the controller may select a value for H' before printing each column of the characters, and H' may be different between at least two columns of the characters.

[0146] An example of this method is in Figures 5B to 5D As given in, Figures 5B to 5D The previous example was based on a known method. Figure 5A The two letters "L" and "M" are printed in 7 rows and 6 columns respectively (including blank columns at the end of each letter), so the 6 columns have a maximum of 7 dots (H=7).

[0147] Figure 5A This is an example based on a known method. Figures 5B to 5D This is an example of another method according to the present invention.

[0148] In the first example ( Figure 5A The maximum number of ink drops is H' = H. All columns are printed using 7 ink drops, meaning each letter requires 7 × 6 = 42 ink drops.

[0149] - Printing an "L" using 42 ink droplets: 7 dots are printed in the first column, so that column requires 7 ink droplets, but each of the other columns only includes one dot, yet uses 7 ink droplets (of which 6 ink droplets do not participate in printing);

[0150] - Similarly, the letter “M” is printed using 42 ink droplets: 7 dots are printed in the first and last columns, so these columns require 7 ink droplets, but each of the other columns only includes one or two dots, yet uses 7 ink droplets (of which 6 or 5 ink droplets do not participate in the printing).

[0151] In a second example of implementing another method according to the invention ( Figure 5B In the middle: the reduced height H' = 6:

[0152] - Print "L" using 7 + 6 × 5 = 37 ink droplets: Print 7 ink droplets in column 1; in each of columns 2-5, print only one dot, but use H' = 6 ink droplets, of which 5 ink droplets do not participate in the printing;

[0153] - Print "M" using 2×7+6×4=38 ink droplets: Print 7 dots in columns 1 and 5; Print only one or two dots in each of columns 2-4, but use H'=6 ink droplets, of which 5 or 4 ink droplets do not participate in the printing.

[0154] For these two letters, less than 42 ink droplets were used, which saved some ink droplets; therefore, the printing speed was faster than expected. Figure 5A It prints faster.

[0155] In the third example ( Figure 5C In the middle: the reduced height H' = 5:

[0156] - Print "L" using 7 + 5 × 5 = 32 ink droplets: Print 7 dots in column 1; Print only one dot in each of columns 2-5, but use H' = 5 ink droplets, of which 4 ink droplets do not participate in the printing;

[0157] - Print “M” using 2×7+6×2+5×2=36 ink droplets: print 7 dots in columns 1 and 5; print only one or two dots in each of columns 2-4, but use H'=5 ink droplets, of which 4 or 3 ink droplets do not participate in the printing.

[0158] 32 ink droplets and 36 ink droplets are respectively smaller than Figure 5B The 37 and 38 ink droplets save more ink droplets; therefore, printing is faster than... Figure 5B It prints faster.

[0159] In the fourth example ( Figure 5D In the middle: the reduced height H' = 4:

[0160] - Printing an "L" using 7 + 5 × 4 = 27 ink drops: Print 7 dots in the first column; in each of the second to fifth columns, print only one dot, but use H' = 4 ink drops, where 3 or 2 ink drops do not participate in printing.

[0161] - Printing an "M" using 2 × 7 + 6 × 2 + 5 + 4 = 35 ink drops: Print 7 ink drops in the first column and 7 ink drops in the fifth column; in each of the second to fourth columns, print only one or two dots, but use H' = 4 ink drops, where 3 or 2 ink drops do not participate in printing.

[0162] The 27 ink drops and 35 ink drops are respectively less than Figure 5C the 32 ink drops and 36 ink drops of Figure 5C , which saves more ink drops; thus the printing is faster than

[0163] According to the present invention, another method for achieving a reduced height H' < H can be applied to printing two-dimensional codes or graphic codes according to the present invention, such as a method of dot code symbols, to implement one or more sets of data or databases.

[0164] Figure 6A and Figure 6B show a printer for implementing the above invention.

[0165] In a multi-deflection continuous jet printer, each ink drop of a single jet (or spaced apart from several jets) can be deflected on different trajectories corresponding to different commands. Thus, a series of ink drops experiencing different commands can scan the area to be printed along the deflection direction, and the other scanning direction of the area to be printed is generated by the relative movement of the print head and the support 800 to be printed (see Figure 6A ). Generally, the components are arranged such that these two directions are substantially perpendicular.

[0166] The deflected continuous inkjet print head has different operating sub-components. Figure 6A Specifically shows the print head of a multi-deflection CIJ printer. The printer includes:

[0167] - Devices 21, 23 for generating an ink drop jet, which are called ink drop generators or stimulants;

[0168] - Device 64 for charging the ink drops (usually one or more electrodes);

[0169] - Device 62 (or "tank") for recovering the ink not used for printing;

[0170] - Device 65 (usually one or more electrodes) for deflecting the charged ink drops for printing;

[0171] - A device that may be used to monitor and control the droplet deflection process (droplet formation and deflection commands are synchronized).

[0172] In the droplet generator 21, conductive ink is supplied to the cavity. This ink, which is held under pressure by the ink circuit 27 that is normally outside the printhead, escapes from the cavity through at least one metering nozzle 6, thereby forming at least one inkjet 11.

[0173] A periodic stimulation device 23 is associated with a cavity upstream of the nozzle 6 that contacts the ink; the stimulation device 23 delivers periodic modulation (pressure) to the ink, thus causing modulation of the jet radius and velocity from the nozzle. When the element is appropriately sized, this modulation is amplified in the jet under the influence of surface tension, which leads to capillary instability in the jet until it breaks down. This breakup is periodic and occurs at a precise distance from the nozzle, at the so-called breakpoint 13 of the jet, the distance of which depends on the stimulation energy.

[0174] In the case where the stimulation device, referred to as the actuator, comprises a piezoelectric ceramic in contact with ink in a cavity upstream of the nozzle, the stimulation energy is directly related to the amplitude of the electrical signal used to drive the ceramic. Other jet stimulation devices (thermal, electro-hydraulic, acoustic, etc.) can also be implemented within the framework of this invention. Due to its efficiency and relative operability, the use of piezoelectric ceramics for stimulation remains a preferred embodiment.

[0175] At its breakpoint 13, the continuous jet from the nozzle transforms into a series of identical and uniformly spaced ink droplets 11. These droplets form at the same time frequency as the stimulus signal; for a given stimulus energy, all other parameters (especially ink viscosity) are stable, and a precise (constant) phase relationship exists between the periodic stimulus signal and the breakpoint, which itself is periodic and has the same frequency as the stimulus signal. In other words, the precise moment of the stimulus signal period corresponds to the precise moment of the dynamic separation of the jet droplets.

[0176] Without further action (where the ink droplets are not used for printing), the droplet string travels along trajectory 7, which is collinear with the ink droplet ejection axis (the nominal trajectory of the jet). This trajectory is connected to the recovery tank 62 via the geometry of the printhead. The tank 62 is used to recover non-printing ink droplets, absorbing unused ink, which is returned to the ink circuit 27 for recycling.

[0177] For printing, the ink droplets are deflected and deviate from the nominal trajectory 7 of the jet. Therefore, the droplets follow an inclined trajectory 9, which encounters the print head 800 at different desired impact points. All these trajectories lie in the same plane. For example, placing the droplets on a droplet impact matrix to be printed on the print head 800 is achieved by combining the individual deflection of the droplets in the printhead deflection plane with the relative motion between the printhead and the print head (typically perpendicular to the deflection plane). In deflection-type continuous jet printing, deflection is achieved by charging the droplets and subjecting them to an electric field. In practice, the device for deflecting the droplets includes at least one charging electrode 64 for each jet, located near the breakpoint 13 of the jet. Each droplet formed with a predetermined charge value is selectively charged, which typically varies from droplet to droplet. For this purpose, the ink is maintained at a fixed potential in the droplet generator 21, and a voltage slot with a defined value, driven by a control signal, is applied to the charging electrode 64, which is different in each droplet cycle.

[0178] In the control signals for the charging electrodes, the voltage is applied shortly before jet segmentation to utilize the electrical continuity of the jet and attract a given amount of charge at the jet tip, which is a function of the voltage value. The variable charging voltage providing deflection is typically between 0 and 300 volts. The voltage is then maintained during segmentation to stabilize the charge until the separated ink droplets are electrically insulated. The voltage is maintained for a certain period after droplet separation to account for momentary breakage.

[0179] A droplet deflection device typically includes a set of two deflection plates 65 located on either side of the droplet trajectory upstream of the charging electrode. These plates are placed at a high, fixed relative potential to generate an electric field Ed substantially perpendicular to the droplet trajectory, thereby enabling the deflection of charged droplets bonded between the plates. The deflection amplitude is a function of the droplets' charge, mass, and velocity.

[0180] The CIJ printhead may also include multiple inkjet cavities for generating multiple inkjets, each cavity having its own nozzle and actuation mechanism, or the same cavity may include multiple nozzles to generate multiple inkjets. As described above, charging electrodes and offset electrodes may be associated with each jet.

[0181] Instructions are sent via control devices (also referred to as "controllers") to activate inkjet-generating devices 21, 23, and / or to activate pumping devices such as tanks, and / or to open and close valves in different fluid (ink, solvent, gas) paths. These instructions also cause ink to circulate under pressure along the directions of devices 21, 23, and then generate a jet according to the pattern to be printed on the holder 800. These control devices or controllers are implemented, for example, as processors or microprocessors, or as circuits or electronic circuits, programmed to implement the method according to the invention, or implement software designed to implement the method according to the invention. The control devices also ensure data storage, for example, storing measurement data of ink levels in one or more storage devices and their potential processing.

[0182] The control device may also store one or more sets of data or databases (DB1, DB2) and / or one or more H' values ​​as described above. More specifically, the data sets or databases and / or H' values ​​may be stored in one or more memories, such as an FPGA, and the data may be read by the aforementioned processor, microprocessor, or electronic circuitry. The controller selects charge data from one or more sets of data or from one or more databases, and the controller controls the application of a corresponding voltage to electrode 64. The control device also controls the voltage applied off the electrode. The charge value may be selected by the controller from the storable H' values, and the controller controls the number of ink droplets required for each column (such that the number of ink droplets (including printing droplets and non-printing droplets) used to print any column is limited to a number H', which is less than the maximum number H of dots in that column, unless printing a particular column requires more ink droplets (in which case more ink droplets are used)).

[0183] Figure 6B This represents the main unit of an inkjet printer that can implement one or more embodiments of the present invention. The printer includes a control console 300, a compartment (or fluid circuit) 400 specifically containing a circuit for regulating ink and solvent, and a reservoir for ink and solvent (particularly, a reservoir to which ink recovered from the tank returns). Typically, the compartment 400 is located in the lower part of the control console. The upper part of the control console includes command and control electronics and a visualization device. The control console is hydraulically and electrically connected to the printhead 100 via an umbilical cord 203.

[0184] A stage (not shown) allows the printhead to be mounted facing the print holder 800, which moves in the direction indicated by the arrow. This direction is perpendicular to, for example, the alignment axis of the nozzle or the offset axis of the ink droplets (see...). Figure 6A (9) Deviation of the jet. The support moves continuously along the X direction. The position of the support relative to the printhead is detected by detector 401.

[0185] This printer can be integrated into packaging machines.

[0186] The printer according to the invention is an industrial printer, capable of printing on uneven surfaces such as cables, bottles, or cans. Another aspect of this printer is that the distance between the printhead and the substrate to be printed is greater than that of a conventional desktop printer. For example, this distance is at least 5 mm, and for instance, between 10 mm and 30 mm.

[0187] Another aspect of this printer is its speed: the maximum speed is between 15-20 m / s, and the nominal printing speed is usually between 1-5 m / s.

[0188] Another aspect of this printer is that it can print on very different surfaces, such as glass, metal, bubbles, or packaging materials.

[0189] Figure 7 An example of a fluid circuit 400 for a CIJ printer to which the present invention can be applied is shown. The fluid circuit 400 includes multiple devices 410, 500, 110, 220, and 310, each associated with a specific function. A printhead 1 and an umbilical cord 203 are also shown.

[0190] Removable ink cartridge 130 and solvent cartridge 140 are associated with the circuit 400, and ink cartridge 130 and solvent cartridge 140 are also removable.

[0191] Reference numeral 410 indicates the main storage unit, which is capable of receiving a mixture of solvent and ink.

[0192] Reference numeral 110 indicates a set of devices capable of extracting solvent from solvent cartridge 140, and possibly storing solvent, and supplying the extracted solvent to other parts of the printer, whether it involves supplying solvent to main storage 410 or cleaning or maintaining one or more other parts of the machine.

[0193] Reference numeral 310 indicates a set of devices capable of drawing ink from cartridge 130 and supplying the drawn ink to main storage 410. As can be seen from the figure, according to the embodiment presented herein, solvent is sent from device 110 to main storage 410 via these same devices 310.

[0194] At the outlet of reservoir 410, a set of devices, generally indicated by reference numeral 220, pressurizes the ink drawn from the main reservoir and sends it to printhead 1. According to the embodiment shown here by arrow 250, these devices 220 can also send ink to device 310 and then to reservoir 410, allowing the ink to be recycled within a loop. This loop 220 also empties the reservoir in cartridge 130 and cleans the connector of cartridge 130.

[0195] The CIJ system shown in the figure also includes devices 500 for recovering fluids (ink and / or solvents) that return from the printhead, more specifically, from the printhead slot 62 or the printhead flushing circuit. Therefore, these devices 500 are arranged downstream of the umbilical 203 (relative to the circulation direction of the fluid returning from the printhead).

[0196] from Figure 7 As can be seen, device 110 can also send solvent directly to these devices 500 without going through umbilical cord 203 or printhead 1 or recycling tank.

[0197] The device 110 may include at least three parallel solvent supply sources, one solvent supply source for the printhead 1, a second solvent supply source for the device 500, and a third solvent supply source for the device 310.

[0198] Each of the above devices is equipped with a valve, preferably a solenoid valve, which can direct the fluid involved to a selected destination. Therefore, solvent can be uniquely sent from device 110 to printhead 1, or uniquely sent to device 500, or uniquely sent to device 310.

[0199] Each of the aforementioned devices 500, 110, 210, and 310 may be equipped with a pump capable of handling the fluid involved (the first pump, the second pump, the third pump, and the fourth pump, respectively). These different pumps ensure different functions (the functions of their respective devices) and are therefore different from each other, even if these different pumps may be of the same or similar type (in other words, no single pump ensures two of these functions).

[0200] Specifically, the device 500 includes a pump (first pump) capable of pumping fluid recovered from the printhead as described above and delivering the fluid to the main reservoir 410. This pump is dedicated to recovering fluid from the printhead and is physically distinct from the fourth pumping device 310 dedicated to delivering ink or the third pumping device 210 dedicated to pressurizing ink at the outlet of the reservoir 410.

[0201] The device 110 includes a pump (second pump) capable of pumping solvent and delivering solvent to the device 500 and / or the device 310 and / or the printhead 1.

[0202] This loop 400 is controlled by the aforementioned control devices, which are typically contained within the control console 300 (Figure 6B).

[0203] This invention can be applied to printing on any surface, but is particularly relevant to surfaces such as cigarette packs or bottle stoppers where space is limited.

Claims

1. A method for printing a graphic code on a surface, the graphic code having H rows and W columns i, i = 1, … W, and the graphic code including a pattern composed of H×W cells, each cell being located at the intersection of a column and a row, each printing unit or dot being formed by ink droplets generated by a print head of a continuous inkjet printer, two consecutive dots in the same column being separated by at least one non - printed unit, the method including, when printing each column: Retrieve or select from at least one set of data or database DB of droplet charges for each of multiple configurations of ink droplets to be printed in a column, for applying a charge to each droplet for printing points in the column, wherein the number of the multiple configurations is less than or equal to 2 if H is even. （H / 2）+1 Alternatively, if H is odd, the number of the plurality of configurations is less than or equal to 2. （（H+1） / 2）+1 ;as well as Generating N1 ink droplets according to the charge retrieved or selected from the at least one set of data or database DB, charging a part of the ink droplets used for printing the dots of the column, and printing the column.

2. The method according to claim 1, wherein, N1 < H.

3. The method according to claim 1 or 2, wherein, Retrieving or selecting the charge: If H is even, then: Retrieve or select from a single set of data or a database DB containing the charge, wherein the number of ink droplets to be printed is equal to 2. （H / 2）+1 ; Alternatively, a search or selection can be made from two sets of data or databases of charge, where the number of ink droplets to be printed in each set of data or database is equal to 2. （H / 2） ; If H is odd, then: Retrieve or select from a single set of data or a database DB containing the charge, wherein the number of ink droplets to be printed is equal to 2. （H+1） / 2）+1 ; Alternatively, a search or selection can be made from two sets of data or databases (DB) of charge, where one set of data or database (DB) is used to configure the number of ink droplets to be printed to be equal to 2. （（H+1） / 2） Another set of data or database DB is used to configure the number of ink droplets to be printed, which is equal to 2. （H-1 / 2） .

4. The method according to claim 1 or 2, wherein: For each even-numbered column i, 1 ≤ i ≤ W, retrieve or select from a first set of data or database DB1 of multiple configurations of droplet charges for printable points in the even-numbered column, the charge to be applied to each droplet for printing the point in column i, if H is even, and the number of the multiple configurations is less than or equal to 2. （H / 2） Alternatively, if H is odd, the number of the plurality of configurations is less than or equal to 2. （（H+1） / 2） One configuration; For each odd column i+1, retrieve or select from a second set of data or database DB2 of droplet charges for multiple configurations of the dots to be printed in the odd column, to be applied to each droplet for printing the dots in column i+1, where if H is even, the number of the multiple configurations is less than or equal to 2. （H / 2） Alternatively, if H is odd, the number of the plurality of configurations is less than or equal to 2. （（H+1） / 2） .

5. The method according to claim 1 or 2, wherein, The sum H + W of H and W is odd.

6. The method according to claim 1 or 2, wherein, Even - numbered cells are printed only in odd - numbered columns, and odd - numbered cells are printed only in even - numbered columns.

7. The method according to claim 1 or 2, wherein, The ink droplets are charged and printed according to a dot matrix pattern.

8. A method for printing a graphic code on a surface, the method including: For each of multiple configurations of dots to be printed in a column, select at least one set of data or database DB of ink droplet charge, wherein the number of multiple configurations is less than or equal to 2. （H / 2）+1 H is an even number; or the number of the plurality of configurations is less than or equal to 2. （（H+1） / 2）+1 H is an odd number; Defining the height H and width W of the printed graphic code based on the at least one set of data or database DB; And Printing the graphic code using the method according to any one of claims 1 or 2, the graphic code having H rows and W columns i, i = 1, … W, and the graphic code including a pattern composed of H×W cells, each cell being located at the intersection of a column and a row, two consecutive dots in the same column being separated by at least one non - printed unit.

9. The method according to claim 8, wherein, The selection of the at least one set of data or database DB includes: For multiple configurations of printable dots, select the first set of data or database DB1 for droplet charge. If H is even, the number of the multiple configurations is less than or equal to 2. （H / 2） Alternatively, if H is odd, the number of the plurality of configurations is less than or equal to 2. （（H+1） / 2） ,as well as For multiple configurations of printable dots, select the second set of data or database DB2 for droplet charge. If H is even, the number of the multiple configurations is less than or equal to 2. （H / 2） Alternatively, if H is odd, the number of the plurality of configurations is less than or equal to 2. （（H+1） / 2） .

10. The method according to claim 1 or 2, wherein, The graphic code is a symbol, and the method further includes: Setting a reduced number of rows H', if H is even, then H' < H / 2, and if H is odd, then H' < (H + 1) / 2; For each column n, 1 ≤ n < W, of the symbol, generating H' ink droplets and printing H' dots or fewer dots in the first H' rows of the column n; If the nth column of the symbol has more than H' dots, or has multiple dots in the rows between row H' and row H, generating more ink droplets and printing the required number of dots in the column.

11. The method according to claim 1 or 2, wherein, The relative speed of the print head of the continuous inkjet printer and the surface (800) is changed.

12. A continuous inkjet printer for printing a graphic code having a height H and a width W on a printing surface, the graphic code having H rows and W columns i, i = 1, … W, and the graphic code including a pattern composed of H×W cells, each cell being located at the intersection of a column and a row, the continuous inkjet printer including: A device (21) for forming a plurality of ink droplets; At least one memory stores at least one set of data or a database DB for the droplet charge of each of a plurality of configurations of ink droplets to be printed in a column, wherein the number of the plurality of configurations is less than or equal to 2 if H is even. （H / 2）+1 Alternatively, if H is odd, the number of the plurality of configurations is less than or equal to 2. （（H+1） / 2）+1 ; A controller programmed to retrieve or select, for each column, a charge to be applied to each ink droplet for printing the column from the at least one set of data or database DB; A device (64) for charging the ink droplets used for printing the column according to the charge; And A device (65) for deflecting the charged ink droplets.

13. The continuous inkjet printer according to claim 12, wherein, The at least one memory stores: The first set of data or database DB1 provides a charge that is applied to the ink droplets for printing each of a plurality of configurations of ink droplets to be printed in an odd-numbered column, wherein the number is less than or equal to 2 if H is even. （H / 2） And if H is odd, the quantity is less than or equal to 2. （（H+1） / 2） ,as well as The second set of data or database DB2 provides charges to be applied to or printed in each of a plurality of configurations of ink droplets to be printed in an even-numbered column, where the number of such configurations is less than or equal to 2 if H is even. （H / 2） And if H is odd, the number of the plurality of configurations is less than or equal to 2. （（H+1） / 2） .

14. The continuous inkjet printer according to claim 12 or 13, wherein, The at least one memory stores: If H is even, then stores: A single set of data or a database DB containing the charge, wherein the number of ink droplets to be printed in the set of data or database DB is equal to 2. （H / 2）+1 ; Alternatively, two sets of data or databases (DB) for the charge, one set for even-numbered columns and the other for odd-numbered columns, wherein the number of ink droplets to be printed in each set of data or databases is equal to 2. （H / 2） ; If H is odd, then stores: A single set of data or a database DB containing the charge, wherein the number of ink droplets to be printed in the set of data or database DB is equal to 2. （H+1） / 2）+1 ; Alternatively, two sets of data or databases (DB) for the charge, one set of data or databases (DB) for configuring the number of ink droplets to be printed equals 2. （（H+1） / 2） Another set of data or database DB is used to configure the number of ink droplets to be printed, which is equal to 2. （H-1 / 2） .

15. The continuous inkjet printer according to claim 12 or 13, wherein, The graphic code is a symbol, and the continuous inkjet printer further includes a memory that stores a reduced number of rows H', where if H is even, H' < H / 2, and if H is odd, H' < (H + 1) / 2. The controller controls the continuous inkjet printer such that: For each column n of the symbol, where 1 ≤ n < W, H' or fewer ink droplets are printed in column n, If the nth column of the symbol that must be printed has more than H' dots or multiple dots in the rows between row H' and row H, the required number of dots is printed in that column.

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