EP2381426A1 - Method for high-resolution printing of a post mark - Google Patents

Abstract

A method of printing two-dimensional bar codes formed of a plurality of elementary modules, black or white, each of the black elementary modules having n lines of ink dots with a first line and a last line and m columns of dots ink with a first column and a last column, in which process at least one of the first and last lines and the first and last columns of each of the black elementary modules is printed adjacent to a white elementary module with a second number of ink dots less than a first number of ink dots with which the other lines or columns are printed.

Description

Field of the invention

The present invention relates exclusively to the field of mail processing and more particularly relates to a method for printing high quality postal impressions on mail items moving at high speed.

Prior art

Conventionally, a postal imprint being a monetary value, the quality of its printing on mail items is paramount in order to avoid any fraud or financial loss for the user in case of rejection of the postage by the postal administration.

With the development of digital postage using secure postal imprints, also called "intelligent" that is to say integrating information coded from the postal data, is posed quite critically this problem of the quality of printing, especially when printing the two-dimensional bar codes that such postal impressions necessarily include.

Therefore, today, postal administrations tend to impose a high resolution printing, typically 600dpi, to allow by increasing the contrast a satisfactory reading of these codes and thus improved control and decryption.

However, it has emerged that this increase in printing resolution is not without causing serious problems, given the high rates of processing of these articles. Indeed, the increase in the quantity of ink necessary for printing, as a consequence of this higher resolution, creates burrs because of the absorption of the paper during the impact of the drops of ink on the envelope. . In addition, beyond at a processing rate of about 4000 envelopes / hour, there is a cloud effect weakening the contrast and then prohibiting any re-reading of the bar code by the postal administration.

There is therefore today a real need not satisfied for a high-speed printing process to ensure a high print resolution and whose implementation is however simple.

Object and definition of the invention

Also, the present invention provides a method of printing two-dimensional bar codes formed of a plurality of elementary modules, black or white, each of the black elementary modules having n lines of ink dots with a first line and a last line and m columns of ink dots with a first column and a last column, in which process at least one of the first and last lines and the first and last columns of each of the black elementary modules is printed adjacent to a module white element with a second number of ink dots less than a first number of ink dots with which the other lines or columns are printed.

Thus, with this high-resolution printing according to two different number of points, the smallest number being reserved for certain particular zones of each black elementary module, it becomes possible to print a perfectly readable two-dimensional bar code whose control by the postal administration is then easy.

According to a preferred embodiment, the first and last lines and the last column of each of the black elementary modules which are adjacent to a white elementary module with said second number of ink dots are printed.

Preferably, said second number of ink spots may be half of said first number of ink dots.

According to the embodiment chosen, it is possible to print the first column of each of the black elementary modules which is adjacent to a white elementary module with said second number of ink dots or with a third number of ink dots less than said second number of ink spots where still it is possible not to print the first column of each of the black elementary modules which is adjacent to a white elementary module.

Advantageously, said elementary modules are squares of n rows and m columns, n being equal to m or even rectangles of n rows and m columns, n being different from m.

Preferably, said second number of ink spots is determined according to the following parameters: elementary module size, moving speed and printing resolution.

The invention also relates to postal impressions of franking machines having two-dimensional bar codes printed according to the aforementioned printing method.

Brief description of the drawings

• les figures 1A, 1B et 1C montrent, pour trois modes de réalisations différents, un détail d'un code à barres bidimensionnel d'une empreinte postale selon l'invention,
• la figure 2 illustre de façon schématique le système permettant l'impression de l'empreinte postale de la figure 1,
• la figure 3 illustre une empreinte postale de l'art antérieur, et
• les figures 4A et 4B sont des détails d'un code à barres bidimensionnel idéal et réel d'une empreinte postale de l'art antérieur.

The features and advantages of the present invention will emerge more clearly from the following description, given by way of non-limiting indication, with reference to the appended drawings in which:

• the Figures 1A, 1B and 1 C show, for three different embodiments, a detail of a two-dimensional bar code of a postal pattern according to the invention,
• the figure 2 schematically illustrates the system for printing the postal imprint of the figure 1 ,
• the figure 3 illustrates a mailprint of the prior art, and
• the Figures 4A and 4B are details of an ideal and real two-dimensional bar code of a postage stamp of the prior art.

Detailed description of a preferred embodiment

A postal stamp as defined by the German postal administration is illustrated in the figure 3 . Of course, similar postal impressions exist with other postal administrations.

This postal imprint consists mainly of three distinct zones. The first zone 10 corresponds to the stamp itself, the second zone 12 corresponds to the identification code of the postal stamp prepared from the postal data and unique for each printed mail article and the third optional zone 14 corresponds to the advertising flame left to the imagination of the shipper user, as the illustrated example suggests.

By postal data, the data appearing on the postal fingerprint are conventionally understood as the postage amount 100, the filing date 102, the postal number of the franking machine 104, the object category 106, the reference to the Postal Administration 108 and any graphic data such as the fixed part of the postal stamp (for example the hunting horn 110 of the "von Thurn und Taxis" coat of arms of the German postal administration), and on the other hand other data such as the different values of the franking counters (ascending and descending counters), the customer identification number, and possibly the sending time. The destination address of the mail may also constitute additional postal data used in the calculation of the authentication code responsible for ensuring the integrity of all the postal data constituting the print.

The identification code is a high-capacity coding code for numeric or alphanumeric data and error corrections, preferably a two-dimensional bar code chosen from among the best known of which: the Aztec code, the Codablock, the Code one, Code 16K, Code 49, data matrix, PDF 417, QR Code or Supercode. The high coding capacity of this type of code thus enables the latter to include not only this unique identification number ensuring that two mail items can not carry the same number but also other information relating to the mail article, such as a reference to the format when it is an envelope with a specific format or those provided by the EPC standard (Electronic Product Code) developed by the standardization organization of the same name and including the country of origin of the code, the manufacturer's number, etc. In this case, the unique identification number is advantageously a sequential number taken from a number range allocated by this organization. But, one can of course also consider a series of number issued by the server of the postal administration or a random number not removable.

In this case, the identification code is formed of a datamatrix code disposed in four contiguous zones, the set encoding the above information. The Figure 4A shows, in an ideal configuration (when printing a single mail piece or a low-speed printing), a detail of such a code with a very high magnification. We can then observe that it is formed of elementary modules 20 - 58, black or white, square (but a rectangular shape is also possible depending on the nature of the code) with a number of pixels (printed ink dots) predetermined. In the illustrated example, each elemental module, black or white, has 49 pixels (7 lines x 7 columns) and is printed at a first resolution of 600 dpi (600 dots per inch), ie one ink dot every 0.042 mm. for a black elementary module (a white module obviously corresponding to an absence of ink).

The Figure 4B illustrates in the same pixel configuration, a real print done at high speed. Once removed from the storage bin, it can then be observed that the ink of the pixels of the black squares 20, 22, 24, 30, 32 has overflowed on the pixels of the white squares they 34, 38, 44, 50, 52 in practice making replay of the impossible code.

According to a first embodiment of the invention and as shown by the detail of the Figure 1A , it is proposed that the pixels of the last column (the right column) of each of the elementary modules forming the black squares and adjacent to a white square (ie having a white square to their right) be printed with a number of ink dots lower, preferably half less, than the one with which the other columns are printed. So, for example, the right column of square 22 will have 3 pixels instead of the 7 pixels of a standard square, which corresponds to the impression of every other pixel, as if the print resolution was divided in pairs, while in practice it remains of course unchanged at 600 dpi. It should be noted that squares 26 and 28 whose right columns are not adjacent to white squares (no white squares to their right) will not benefit from this reduction in the number of ink dots printed at their column. right.

In addition, the inventors have found that in practice due to the particular position of the print head, the effect of paper absorption causes an ink overflow both upward and downward. elementary modules forming the black squares surrounded by white squares and therefore they proposed to also reduce the number of ink spots of the first line (high line) and the last line (low line) of each of these black elementary modules, as shown in the Figure 1B . Thus, if we are still interested in the square 22 at the top right, we can see that both its high line and its low line has 3 pixels instead of the 7 pixels of a standard square, which corresponds well to the impression of a pixel on two. It will be noted that the superimposed black squares 24 and 28 do not benefit from this reduction in the number of ink spots for their two adjacent lines, namely the low line of the square 24 and the high line of the square 28.

Finally, figure 1C illustrates a last embodiment of the invention in which, to overcome the speed of movement of the mail items and the cloud effect resulting from the increase in the resolution, each of the black squares 20, 22, 24, 26, 32 preceded by a white square is amputated from its left column (its first column adjacent to this white square) so as to ensure a perfect separation of the isolated black squares 20, 22, 32 with the block of squares 24 - 30 for example. Of course, one could also consider an intermediate solution where this left column would not be amputated in its entirety but would however include the second number of points above or a third number of points greater than this second number of points. Thus, for example, such a column could have 2 pixels instead of the aforementioned 7 standard pixels (2 being less than 3).

The figure 2 shows schematically the printing system of the franking machine for printing the postal imprint including its two-dimensional bar code 12 on a mail piece. More particularly, this system comprises a print head 60 supplied with ink from an ink tank 62 under the control of a control module 64. This control module is adapted to control the ejection of the ink onto the printer. article of mail by the various inkjet nozzles 60A of the print head and in particular, according to the invention, to print the number of points of suitable ink, normal or reduced, at the level of the last column or first and last lines of the black elementary modules, according to the disposition of each of these black elementary modules in the barcode, the reduced number of ink points may also be different for the columns and lines.

Note that if the preceding figures refer to elementary modules of 49 pixels, it is understood that this number is given for illustrative purposes and a different number, especially higher is of course possible. In this case, a number of points less ink may be applied not only to the last column and the first and last lines but also to one or more columns or lines adjacent to them, without their respective number exceeding more than half of the other columns or printed lines normally. Thus, for a square of 81 pixels, it is conceivable to print with a smaller number of ink spots the last two columns and the first two and last lines instead of one.

It will also be appreciated that if the principle of halving the number of printed ink dots is the preferable embodiment, a ratio different from and smaller than 2 may be adopted.

More generally, the second number of points is determined according to the following parameters: dimension of the elementary modules, speed of displacement and resolution of printing. Thus, the second number of points can be increased in proportion to the increase in the size of the elementary module or the print resolution. It is the same with the speed of movement of the articles to be printed. However, the inventors have noted that for a speed of less than 4000 envelopes / hour, the amputation of the left column of the elementary modules is not necessary.

Claims (10)

A method of printing two-dimensional bar codes formed of a plurality of elementary modules, black or white, each of the black elementary modules having n lines of ink dots with a first line and a last line and m columns of dots ink with a first column and a last column, in which process at least one of the first and last lines and the first and last columns of each of the black elementary modules is printed adjacent to a white elementary module with a second number of ink dots less than a first number of ink dots with which the other lines or columns are printed. The method of claim 1, wherein the first and last lines and the last column of each of the black elementary modules which are adjacent to a white elementary module are printed with said second number of ink dots. The method of claim 1 or claim 2, wherein said second number of ink dots is one-half of said first number of ink dots. The method of claim 1 or claim 2, wherein in addition the first column of each of the black elementary modules which is adjacent to a white elementary module is printed with said second number of ink dots. A method according to claim 1 or claim 2, wherein in addition the first column of each of the black elementary modules which is adjacent to a white elementary module is printed with a third number of ink dots less than said second number of dots. 'ink. A method according to claim 1 or claim 2, wherein in addition the first column of each of the black elementary modules that is adjacent to a white elementary module. The method of any one of claims 1 to 6, wherein said elementary modules are squares of n rows and m columns, n being equal to m. The method of any one of claims 1 to 6, wherein said elementary modules are rectangles of n rows and m columns, n being different from m. The method of any one of claims 1 to 6, wherein said second number of ink spots is determined based on the following parameters: elementary module size, moving speed, and print resolution. Postage imprint comprising a two-dimensional bar code printed according to the printing method of claims 1 to 9.

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