JP2011046003A - Two-dimensional code generation system, two-dimensional code generation program and inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To generate a two-dimensional code in stable quality even when bleeding occurs, without the need of complicate ejection control and without changing the whole size of the two-dimensional code. <P>SOLUTION: When creating the two-dimensional code prior to printing on a printing medium, the two-dimensional code comprised of black cells and white cells by a recording head with nozzle arrays, a side 62 on the downstream side in a conveyance direction of each black cell is thinned at least by a one-dot width. The number of dots in a width x of the side 62 is determined according to at least one of a type of the printing medium used, a head temperature, an environmental temperature, a conveyance speed and the size of the two-dimensional code. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an inkjet recording apparatus, and a two-dimensional code generation system and a two-dimensional code generation program using the same.

  In general, a barcode generation system using an ink jet recording head has an advantage that an image can be formed in a non-contact manner on various printing media (media), but due to a phenomenon that ink droplets spread on the paper surface, The black bar of the bar code tends to be thick and the white bar adjacent to it tends to be thin. Originally, a black bar and a white bar (white space) need to have the same width, so the thickness of the bar greatly affects the barcode reading accuracy, and sometimes the barcode becomes unreadable. There was a problem that.

  The same applies to the two-dimensional code barcode. A two-dimensional code is a combination of small square elements of black and white. This minimum square element (hereinafter referred to as a cell) must be the same size for both black and white. However, in an inkjet recording apparatus, particularly an inkjet recording apparatus that forms an image in one pass, bleeding occurs in the paper conveyance direction, and cells that should be formed in a shape that should be originally formed (for example, a square) are inherent. There was a problem of losing shape.

  As a means for solving this problem, a method has been proposed in which ink having a different discharge amount is applied to the edge portion of the barcode to prevent excessive bleeding (see Patent Document 1).

  In addition, in the problem that the white bar becomes small due to the occurrence of blur and the barcode reader cannot detect the white bar, the white size can be read even if blur occurs by increasing the image size itself including the barcode. A method of taking a sufficient space in the part has also been proposed (see Patent Document 2).

  As a means of solving the problem that the desired bar code rank cannot be obtained due to the difference in black bar and white space width due to blurring, 1 dot measured in advance so that the black and white bar widths are the same. A method of calculating the number of dots so that the widths of the black bar and the white bar are the same from information such as the line width and the resolution of the printing apparatus has been proposed (see Patent Document 3).

  In addition, since the degree of ink bleeding largely depends on the paper material, there is a problem that the barcode cannot be read if the paper type is changed. As a means for solving this problem, a method has been proposed in which the number of dots of black bars and white bars is prepared in advance as a table for each paper type to cover excessive bleeding due to the difference in paper type (Patent Document 4). reference).

JP 2000-103042 A JP 2007-268773 A JP 2003-001804 A JP 2005-047169 A

  However, the barcode generation system disclosed in Patent Document 1 is a method for preventing the enlargement of the bar width of a one-dimensional barcode by discharging small dots uniformly on one side in the width direction of a black bar. It does not adjust the cell size. Further, since it is necessary to have a plurality of types of ink droplet sizes by changing the head driving method, the ejection control becomes complicated.

  The nozzle calculation method described in Patent Document 2 is also a one-dimensional barcode width adjustment method, and in order to apply to a two-dimensional code, it is necessary to perform vertical and horizontal bar width data and calculation for the recording head, respectively. When the bar width in any one direction is used to correct the two-dimensional code, particularly in an ink jet recording apparatus that performs printing in one pass, the width may vary greatly depending on the bar forming direction with respect to the recording head. Since there are many, there is a problem that a deviation occurs between the calculation and the verification result.

  In the printing apparatus described in Patent Document 3, since the image itself is enlarged, it is considered that there is no actual harm if the space between the objects has a margin, but the balance of the layout is slightly different from the intended one. There is a problem that becomes a thing. Furthermore, there is a possibility that the bar code approaches an adjacent image and a quiet zone necessary for reading cannot be sufficiently secured.

  The inkjet recording apparatus described in Patent Document 4 is also a one-dimensional barcode correction method, similar to the cited document. Since the black bar width and white space width of the barcode are changed depending on the type of paper, the overall size of the barcode may change depending on the selected paper. In addition, it is necessary to prepare a plurality of correction value tables corresponding to the respective paper types. Furthermore, for the two-dimensional code, correction values in the vertical and horizontal directions with respect to the recording head must be prepared. Therefore, in this case, there is a problem that the code correction table becomes complicated.

  The present invention has been made in such a background, and the object thereof is to eliminate the need for complicated discharge control and to change the size of the entire two-dimensional code even if bleeding occurs. An object of the present invention is to provide an ink jet recording apparatus capable of generating a quality two-dimensional code.

  In the two-dimensional code generation system according to the present invention, a two-dimensional code composed of black cells and white cells is conveyed relative to the recording head by a recording head having a nozzle row composed of a plurality of nozzles each ejecting ink. In the two-dimensional code generation system generated for printing on a printing medium, the side on the downstream side in the transport direction of each black cell is thinned out by at least one dot width. This prevents the deterioration of the quality of the two-dimensional code due to the influence of so-called satellites.

  In this configuration, regardless of whether a plurality of black cells are adjacent to each other to form a larger black cell region, thinning is performed uniformly on the downstream side in the transport direction for each black cell unit. Becomes easy.

  For example, by using a thinning pattern table that stores a thinning pattern that thins out the downstream side in the transport direction of each cell of the image area constituting the two-dimensional code with a width of at least one dot, the thinning pattern is converted into an image of the two-dimensional code. By applying, thinning processing can be performed.

  Alternatively, there may be provided means for detecting the cell size and thinning means for thinning out a predetermined number of dots at regular intervals corresponding to the cell size in the transport direction in the image area of the two-dimensional code.

  The number of dots in the width of the downstream side can be determined according to at least one of the type of print medium to be used, the head temperature, the environmental temperature, the conveyance speed, and the size of the two-dimensional code.

  Further, along with the downstream side of each black cell in the transport direction, a side perpendicular to the side may be thinned out with a width of at least one dot. Thereby, not only the influence of the satellite but also the deterioration of the quality of the two-dimensional code due to the influence of the ink bleeding is effectively prevented.

  A two-dimensional code generation program according to the present invention is configured to convey a two-dimensional code composed of black cells and white cells relative to the recording head by a recording head having a nozzle row composed of a plurality of nozzles each ejecting ink. A two-dimensional code generation program that is generated for printing on a print medium that causes a computer to execute a step of thinning out at least one dot width on the downstream side in the transport direction of each black cell. is there.

  Further, the ink jet recording apparatus according to the present invention transports a two-dimensional code composed of black cells and white cells relative to the recording head by a recording head having a nozzle row composed of a plurality of nozzles each ejecting ink. In the recording apparatus for printing on the print medium, the side on the downstream side in the transport direction of each black cell is thinned out by at least one dot width.

  According to the present invention, in the two-dimensional code generation in an ink jet recording apparatus in which ink bleeding or satellite occurs, it is possible to generate a two-dimensional code that matches the user's individual use environment conditions such as the installation environment of the recording apparatus and the type of printing medium. A two-dimensional code generation system can be provided.

  Further, in the two-dimensional code generation system of the present invention, correction is simply performed at regular intervals for each black cell without performing complex correction such as detecting only the end of the black area of the two-dimensional code. As a result, it is possible to obtain the same correction effect as when performing complex correction.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view schematically showing a schematic configuration of a recording apparatus that is an example of a barcode printing apparatus of an ink jet recording system according to a first embodiment of the present invention. FIG. 2 is a diagram illustrating an electrical system (hardware configuration) of the recording apparatus illustrated in FIG. 1. It is an enlarged view of a pattern when a pattern of a two-dimensional code is printed for explaining a conventional problem. FIG. 3 is a schematic diagram illustrating a state until a satellite is landed on a sheet in an inkjet recording apparatus. It is the figure which exaggerated and showed the mode of the two-dimensional code when a satellite generate | occur | produced, and a satellite. It is the figure which showed the example of the correction method of the two-dimensional code in embodiment of this invention. It is the figure which expanded and showed the recording result of the one part cell of the after-thinning image data in embodiment of this invention. It is the figure which showed the example of the thinning-out about the black cell area | region of the two-dimensional code influenced by a satellite. It is a flowchart showing the process until the two-dimensional code generation of the two-dimensional code generation system in embodiment of this invention. It is a figure for demonstrating the modification of embodiment of this invention. It is a figure for demonstrating the specific example of the two-dimensional code in embodiment of this invention. It is a figure for demonstrating the pattern of the concrete two-dimensional code of the modification of embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the component described in the following embodiment is an illustration to the last, and is not a thing of the meaning which limits the scope of the present invention only to them.

  FIG. 1 schematically shows a schematic configuration of an inkjet recording apparatus 10 which is an example of a barcode printing apparatus of the inkjet recording system in the first embodiment. The ink jet recording method is assumed to employ an ink discharge method using thermal energy. However, other ink ejection methods may be used. The recording apparatus 10 assumes a so-called one-pass type in which an image is formed by passing a print medium once under the print head relative to the recording head when a two-dimensional code is printed. Yes.

  The recording apparatus 10 is connected to a host computer (PC) 12 (see FIG. 2), and receives image information and a print instruction from the host computer 12. The host computer 12 includes means for generating a two-dimensional code. As a configuration according to the present invention, the type, size, data, etc. of any two-dimensional code to be printed by the user, the type of paper to be printed, the conveyance speed, etc. Condition input means for inputting printing conditions is provided.

  The user inputs these settings on the application in the PC, and the input data is reflected in the two-dimensional code generation. The recording apparatus 10 includes six (six) recording heads 22K1, 22K2, 22K3, 22K4, 22K5, and 22K6 as a plurality of line heads arranged in parallel. Each recording head is a so-called line head in which a nozzle row composed of a plurality of nozzles is arranged in the width direction of a print medium (roll paper in this case) P. Each line head extends in a direction orthogonal to the paper surface of FIG. 1 (that is, a direction orthogonal to the arrow C direction), and the plurality of line heads are arranged side by side in the conveyance direction (arrow C direction) of the print medium P. Yes. Each color ink is ejected from the six recording heads. The length of the nozzle row of each line head is slightly longer than the maximum width (the length in the direction perpendicular to the paper surface of FIG. 1) of the print medium that can be printed by the recording apparatus 10. Further, these recording heads 22K1, 22K2, 22K3, 22K4, 22K5, and 22K6 are fixed and do not move during image formation (is in an immobile state).

  A recovery unit 40 is incorporated in the recording apparatus 10 so that ink can be stably ejected from the six recording heads 22K1, 22K2, 22K3, 22K4, 22K5, and 22K6. By this recovery unit 40, the ink discharge state from each recording head is restored to the initial good ink discharge state. The recovery unit 40 is provided with a capping mechanism 50 that removes ink from the respective ink discharge port forming surfaces (face surfaces) 22Ks of the six recording heads during the recovery operation. The capping mechanism 50 is provided independently for each recording head. The capping mechanism 50 includes a known wiper blade, a blade holding member, a cap, and the like.

  The roll paper P is supplied from the roll paper supply unit 24 and is transported in the direction of arrow C by the transport mechanism 26 incorporated in the recording apparatus 10. The transport mechanism 26 includes a transport belt 26a that loads and transports the roll paper P, a transport motor 26b that rotates the transport belt 26a, a roller 26c that applies tension to the transport belt 26a, and the like.

  When forming an image on the roll paper P, after the recording start position of the roll paper P being conveyed reaches below the recording head 22K1, ink is selectively selected from the recording head 22K1 based on the recording data (image information). To discharge. Similarly, each ink is ejected in the order of the recording head 22K2, the recording head 22K3, the recording head 22K4, the recording head 22K5, and the recording head 22K6 to form an image on the roll paper P. In addition to the above components and members, the recording apparatus 10 includes a main tank 28K that stores ink supplied to the recording heads 22K1, 22K2, 22K3, 22K4, 22K5, and 22K6, and recording heads 22K1, 22K2, 22K3, Various pumps (not shown) for supplying ink to 22K4, 22K5, and 22K6 and performing a recovery operation are provided.

  Next, an electrical system (hardware configuration) of the recording apparatus 10 will be described with reference to FIG.

  Recording data and commands transmitted from the host computer 12 are received by the CPU 100 via the interface controller 102. The CPU 100 is an arithmetic processing unit that constitutes a control unit that performs overall control such as reception of recording data of the recording apparatus 10, recording operation, handling of the roll paper P, and the like. After analyzing the received command, the CPU 100 renders the image data of each color component of the recording data by developing a bitmap on the image memory 106. As an operation process before recording, a capping motor 122 and a head up / down motor (head motor) 118 are driven via an input / output port (I / O) 114 and a motor driving unit 116, and each recording head 22K1, 22K2, 22K3 is driven. , 22K4, 22K5, and 22K6 are moved away from the capping mechanism 50 (FIG. 1) to the recording position (image forming position).

  Subsequently, the roll paper is driven by driving the input / output (I / O) port 114, the roll motor 124 that feeds the roll paper P through the motor driving unit 116, the transport motor 120 that transports the roll paper P at a low speed, and the like. P is conveyed to the recording position. The front end position of the roll paper P is detected by a front end detection sensor 111 for determining the timing (recording timing) at which ink starts to be ejected onto the roll paper P conveyed at a constant speed. This detection output is given to the CPU 100 via the input / output port 113.

  Thereafter, in synchronism with the conveyance of the roll paper P, the CPU 100 sequentially reads out the corresponding color recording data from the image memory 106, and the read data is recorded via the recording head control circuit 112. Transfer to the heads 22K1, 22K2, 22K3, 22K4, 22K5, 22K6. The recording heads 22K1 to 6 are provided with temperature sensors 168, respectively. The recording head control circuit 112 controls the ejection of each head based on the temperature detected by the temperature sensor 168.

  The operation of the CPU 100 is executed based on a processing program stored in the program ROM 104. The program ROM 104 stores processing programs and tables corresponding to the control flow. A work RAM 108 is used as a working memory. The EEPROM 115 is a rewritable nonvolatile memory that stores various data (setting data, registration data, adjustment values, etc.) that need to be stored in a nonvolatile manner. During the cleaning and recovery operations of the recording heads 22K1, 22K2, 22K3, 22K4, 22K5, and 22K6, the CPU 100 drives a pump motor (not shown) via the input / output port 114 and the motor driving unit 116 to add ink. Control pressure, suction, etc.

  FIG. 3A shows an enlarged view of a pattern when a pattern composed of black cells and white cells, such as a two-dimensional code, is printed by the recording head. In the present specification and claims, a “black cell” means a cell filled with ejected ink, and the color of the ink is not necessarily black. The “white cell” means a cell formed by the background color of the paper without ejecting ink. Therefore, the background color of the paper is not necessarily white.

  The size of the dots formed by the ink jet recording method is based on the characteristic of forming an image by discharging a liquid called ink, and the amount of ink discharged depending on conditions such as the use environment, individual differences in the recording head, and the type of ink, Also, it varies depending on the bleeding rate depending on the material of the paper. Even if a black cell and a white cell are formed in the same size on the image data (FIG. 3B), the size of the black cell and the white cell differs as shown in FIG. W (a) <W and B (a)> B).

  When the discharge amount is larger than the design center value or the sheet bleeding rate is large, the black cells are further larger and the white cells are smaller as shown in FIG.

  Conversely, when the ejection amount is small or the sheet bleeding rate is small, as shown in FIG. 3D, the black cells are smaller and the white cells are larger than those in FIG. 3C (W (c)). <W (d), B (c)> B (d)).

  Such a difference in the size of the black cell / white cell greatly affects the reading accuracy of the two-dimensional code, and the reading rank is lowered as compared with the case where the two-dimensional code is formed with an ideal dot size. In the worst case, it may become unreadable.

  The problems that occur when printing a two-dimensional code with an inkjet recording apparatus are not only the problem of size due to the size of the white cells being blurred, but also the reflectance of the white regions. There is also a decrease in the modulation value (hereinafter referred to as MOD value) that occurs when the value is not sufficient.

  As described above, since the ink jet recording apparatus forms an image by oozing ink, even if black cells and white cells are formed with the same number of dots as shown in FIG. The cells are not the same size. For this reason, in order to improve the quality of the two-dimensional code, it is necessary to perform some kind of ejection control and image processing control.

  Further, in order to generate a two-dimensional code in an ink jet recording apparatus, it is necessary to consider not only this bleeding but also the influence of satellites.

  FIG. 4 is a schematic diagram showing how the satellite in the ink jet recording apparatus lands on the paper. When the ink is ejected from the head 22K1, after the main droplet 401 of the ink forming the image has landed on the paper P (FIGS. 4A to 4C), the remaining of the main ink droplet is delayed from the main ink droplet 401. (Sub-droplet) 402 lands on the paper (FIG. 4D). Such a secondary droplet is called a satellite.

  FIG. 5A shows a state of the two-dimensional code when the satellite 402 is generated. FIG. 5B is an exaggerated view of the satellite 402.

  Since the satellite 402 is always formed on the rear side in the paper conveyance direction with respect to the landing of the main droplet 401, the satellite 402 is black in the direction along the conveyance direction (perpendicular to the nozzle row) as shown in FIG. There is a possibility that the cell width B becomes extremely larger than the width of the white cell W (B> W). Further, as shown in FIG. 5B, when a square cell is to be formed, the length is a satellite with a black cell length B (H) along the transport direction and a vertical length B (V) thereof. It differs depending on the influence of 402, and B (H)> B (V). Similarly, in the white cell, the white cell length W (H) and the vertical length W (V) along the conveyance direction satisfy W (H) <W (V). Thus, neither black cells nor white cells are square. However, the original cell may not be square. The problem is that the original cell shape changes from the desired shape due to the influence of the satellite.

  The landing position of the satellite 402 varies depending on the conveyance speed of the recording apparatus that forms the two-dimensional code. If the transport speed is high, the difference between the landing positions of the satellite 402 and the main droplet 401 becomes large. Further, depending on the spread of the paper P used for printing, there is a difference in how the satellites 402 come out. Furthermore, the satellite 402 is generated differently depending on the environmental temperature at which printing is performed and the temperature of the recording head 22K1. This is because the viscosity and surface tension of the ink change depending on the temperature of the ink, and there is a difference in the discharge amount that the nozzle discharges the ink. In general, as the temperature rises, it becomes easier to eject ink and the ejection amount increases, and at the same time, the satellite amount also increases.

  In the present embodiment, the recording apparatus in the case where the recording head 22K1 is fixed and the image is formed by moving the paper P has been described. However, the recording is of a type in which the image is formed by fixing the paper and moving the recording head. Satellites are generated in the same way. Therefore, the present invention can be applied to a two-dimensional code generation system that generates a two-dimensional code on a print medium that is conveyed relative to the recording head.

  FIG. 6 shows an example of a two-dimensional code correction method in the present embodiment.

  Uniformly for each black cell in the cycle of the minimum cell size of the two-dimensional code (L dots in the figure) x dot width x L dot length (x < The recording dots in the portion L) are thinned out (that is, removed). Here, thinning out the recording dots means that the ON pixels constituting the image of the two-dimensional code are changed to OFF pixels, thereby suppressing ink ejection to be performed on the pixels.

  Therefore, in this embodiment, a thinning pattern 60 as shown in FIG. 6B is prepared. The thinning pattern has a size corresponding to the image area constituting the two-dimensional code (that is, the printing area of the two-dimensional code), and thins out the downstream side of each cell of the two-dimensional code with a width of at least one dot. This is a pattern that determines whether or not to perform thinning out in units of pixels. This thinning pattern 60 shows an example in which the downstream side in the transport direction of each cell is thinned by the x dot width in the cycle of the minimum cell size L. In this example, for each L dot in the transport direction, a linear portion 61 (white stripe portion in the figure) extending in a direction perpendicular to the transport direction corresponds to an OFF pixel to be thinned. In the present embodiment, all the recording dots of the linear portion 61 are removed, but it is also possible to thin out so as to leave a part of the recording dots of the linear portion 61. For example, one or more recording dots may be left every other dot or every plural dots in the longitudinal direction of the thinning target side.

  By applying this thinning pattern 60 to the image data of the two-dimensional code as shown in FIG. 6A, the thinned image data as shown in FIG. 6C is generated. As can be seen from FIG. 6C, the side 62 on the downstream side in the transport direction of each black cell is removed from the thinned image data.

  However, the use of a thinning pattern is not essential. It is only necessary to perform processing for periodically changing the ON pixel at the rear end of the black cell to the OFF pixel for the image data of the two-dimensional code.

  FIG. 7 shows an enlarged recording result of some cells of the thinned image data. As shown in the figure, a satellite 402 is generated, and only the portion δS where the satellite 402 is eroded into the white cell portion is compared with the original data of the two-dimensional code (FIG. 6A) in the transport direction of the black cell. The downstream side is thinned out uniformly with x dot width. As a result, the portion δS where the satellite 402 is generated is included in the black cell and brought close to the minimum cell size L, whereby the size B of the black cell and the size W of the white cell become the same (L = B = W ), The quality of the two-dimensional code can be stabilized.

  As shown in FIG. 8, for the black cell region of the two-dimensional code affected by the satellite 402 (a region where a plurality of black cells are continuous in the transport direction), only the portion on the rear end side in the transport direction is thinned out. It's enough. (In other words, it is not necessary to thin out the trailing edge side for all black cells.) However, in order to select and thin out only the trailing edge portion of the black cell area, it is necessary to detect the black cell area, and the processing is complicated. become. Actually, a sufficient effect can be obtained by performing the thinning process uniformly on each black cell by the thinning pattern as shown in FIG. 6B for each black cell of the two-dimensional code. Such a complicated thinning-out process is not necessary.

  Table 1 shows a correction method in which thinning processing is uniformly performed on each black cell as shown in FIG. 6, and correction in which thinning processing is performed only on black cells downstream in the transport direction of the black cell region as shown in FIG. The two-dimensional code quality when performing the two correction methods is summarized.

  This is a two-dimensional code modulation (hereinafter referred to as MOD) verification result when x dots are thinned out to 0 dots (no correction), 1 dot, 2 dots,. “Modulation” indicates whether the reflectance of a bright module and a dark module is in accordance with the standard. A “module” is the smallest unit cell that constitutes a symbol of a two-dimensional code. This MOD value represents variation in unevenness of the two-dimensional code. The ratio of the reflectance of the actual two-dimensional code portion is verified and ranked with respect to the maximum reflectance of the white portion and the minimum reflectance of the black portion. When no correction is performed, the MOD rank is low (D rank). This is because, as described with reference to FIG. 5, the black area erodes in the white cell area due to the influence of the satellite, and the white reflectance is not sufficient because the size of the white cell is not sufficient. On the other hand, the MOD value increases from D rank to B rank and further to A rank by thinning out the dots of black cells or black cell areas with the width of 1 dot, 2 dots and 3 dots, respectively. . This indicates that the original data of the two-dimensional code is thinned by the amount of satellite generation, so that the size of the white cell is sufficiently increased and the reflectance of the white region is stabilized. As can be seen from Table 1, the same results were obtained in both FIGS. 6 and 8 with different correction methods. Therefore, it can be said that there is no problem in the quality of the two-dimensional code obtained even if the correction method by simple processing as shown in FIG. 6 is adopted.

  There is no difference between the verification results of the two-dimensional code in which the black area is uniformly thinned out as shown in FIG. 6 and the two-dimensional code in which only the end portion is thinned out as shown in FIG. by. Even if white streaks are generated at regular intervals due to thinning correction in the black cell area, white lines narrower than the specified width cannot be determined as complete white at the normal resolution of the verifier. Recognize the same black. Moreover, in practice, if the white stripe has a width of about 1 to 3 dots, the ink will bleed out, which is a level that is difficult to distinguish visually. For example, a white stripe of 0.1524 mm or less cannot be identified with a 6 mil verification machine. This 0.1524 mm is an interval of a little less than 5 dots in a 600 dpi recording apparatus, for example. Since the number of correction dots in the present invention is at most 2 to 3 dots, it is sufficiently smaller than the width that the verifier can discriminate. Therefore, even if a complicated correction method as shown in FIG. 8 is not performed, it can be said that the correction method that simply thins out the black area uniformly as shown in FIG. 6 is sufficiently effective.

  Table 2 is an example of a thinning table for determining the number of dots to be thinned out for one black cell.

  The width of the black cell thinning target (the number of thinning dots) is determined prior to the generation of the two-dimensional code. The actual number of thinned dots is determined by the paper type selected by the user, the head temperature, the conveyance speed, and the size of the two-dimensional code. Table 2 is an example of a thinning table based on the paper type. Paper that tends to bleed (paper A) has large thinned dots, and paper (paper C) that hardly bleeds has fewer thinned dots (or no correction is performed).

  Factors that determine the number of thinned dots are related to the type of print medium used, the head temperature, the environmental temperature, the conveyance speed, and the size of the two-dimensional code in addition to the paper type. Therefore, although not shown, a thinning table in which an appropriate number of thinning dots is determined according to a combination of these plural factors may be used.

  Alternatively, for each factor other than the paper type, the number of thinned dots for the paper type may be corrected for each paper type according to the determination result of the factor. For example, if the factor is the head temperature or the environmental temperature, the number of thinned dots is increased as the temperature increases. When the factor is the transport speed, the output is likely to be affected by the satellite when the transport speed is fast, so the number of thinned dots is increased, and when it is slow, the number of thinned dots is decreased. When the factor is the two-dimensional code size, the number of thinned dots is reduced or the correction is not performed for a two-dimensional code having a large size. This is because the two-dimensional code generally has a larger dimensional tolerance as the size of the code increases, and the quality becomes sufficient without correction. Therefore, when the two-dimensional code size does not need to be corrected, the processing load can be reduced by not performing the correction.

  The data of the two-dimensional code subjected to the thinning correction in this way is transferred to the recording device, and an image corrected by the recording device is output.

  FIG. 9 is a flowchart showing processing up to the two-dimensional code generation of the two-dimensional code generation system in the present embodiment. This process is assumed to be executed by a control unit (not shown) in the PC. However, it can also be executed on the recording device side.

  The user inputs conditions such as the type and size of the two-dimensional code, the data to be two-dimensionally encoded, the paper type, and the conveyance speed (S1). Based on this, a two-dimensional code is generated (S2). Next, the minimum cell size L of the two-dimensional code to be generated is detected (S3). Thereby, the thinning cycle L is determined. The thinning table is referred to based on the paper to be used (S4). Thereby, the number of thinning dots x dots is determined (S5). Data is created by uniformly thinning out the sides of black cells of x dot width at intervals of L dots in the direction perpendicular to the nozzle row direction (cycle L) (S6). Thereafter, the created data is transferred to the recording device (S7). The recording device performs a printing operation, and the transferred data is printed. The thinning cycle needs to be synchronized with each cell of the two-dimensional code. In other words, it is necessary that the start of a constant interval period for thinning out dots coincides with the front end of two-dimensional code printing.

  The area where the dots are thinned out is an area including a two-dimensional code. By providing a means for detecting the area where the two-dimensional code is printed and by suppressing the thinning processing in other areas, other images are thinned out. This may be prevented.

  In the processing of this embodiment, the width of the black cell side (the number of thinning dots) is determined according to the paper P to be used, but as described above, the thinning table depends on the head temperature, the conveyance speed, and the size of the two-dimensional code. And the number of correction dots may be determined.

  As described above, the correction in the two-dimensional code generation system according to the present embodiment is to thin out the side of each black cell on the downstream side in the transport direction with at least one dot width. For this purpose, a simple process of thinning the black region of the two-dimensional code to a minimum cell size and uniformly thinning at a constant interval with a width of one dot or several dots may be performed. This makes it possible to perform stable quality two-dimensional code printing without performing complicated processing such as correcting only the downstream side in the transport direction affected by the satellite in the black area of the two-dimensional code. .

  In the above description, the process of thinning out the sides of the black cells perpendicular to the transport direction (parallel to the nozzle row direction) is performed as correction for the occurrence of satellites. On the other hand, as shown in FIG. 10, it is also possible to thin out the sides of the black cells parallel to the transport direction. In particular, when paper or ink with large bleeding is used, the size of the black cell increases not only in the satellite generated on the rear end side of the black cell in the transport direction but also in the direction perpendicular to the transport direction. The black cell side (the lower end of the black cell in the figure) in the direction perpendicular to the transport direction may be thinned by the amount of bleeding. As shown in FIG. 10B, a thinning pattern that thins out the side (x dot width) on the downstream side of the black cell in the transport direction and the side (bottom side in the figure) portion (y dot width) perpendicular to the black cell. Is used. In general, x> y. By applying the thinning pattern as shown in FIG. 10B to the image data in FIG. 10A, the thinned image data in FIG. 10C is obtained. By thinning out with different dot widths as shown in FIG. 10B, the sizes of the black cells and the white cells can be made closer to each other.

  With reference to FIG. 11, a PDF 417 will be described as a specific example of the two-dimensional code.

  A quiet zone 1301 is a blank portion before and after a two-dimensional code necessary for reading a two-dimensional code, and is also called a margin. If another symbol or the like enters the quiet zone 1301, it cannot be recognized as a two-dimensional code. The start pattern 1302 represents the start of the symbol, and the stop pattern 1303 represents the end of the symbol. The left / low indicator 1304 and the right / low indicator 1305 are present on the left and right of each row, and indicate the row number, the number of digits of the symbol, the number of columns, and the contents of the security level.

  A data code word 1306 arranged between the left row indicator 1304 and the right row indicator 1305 is a basic unit of coded symbol characters, as shown in FIG. 11B, and has 17 modules (ie, cells). It starts with black cells from the left and is expressed by four combinations of black cells and white cells. 2 [byte] characters such as Chinese characters are converted into 2 code words, TEXT is converted into 1 code word with 2 characters, and numbers are converted into 1 code word with 3 digits.

As shown in FIG. 11B, the minimum value of each module of the black cell and the white cell is width: 191 [μm] (min.)
Height: 254 [μm] (min.)
It is. For example, if the recording resolution of the recording head is 600 [dpi], this dimension is a pitch between dots: 42.5 [μm].
Width: 5 dots Height: 6 dots is the standard minimum value. However, depending on the recording method of the recording head, there may be a large variation in the recording result. Therefore, in actual use, a dimension that is three times or more is recommended. Therefore, the recommended value is the calculation of width: 14 dots, height: 18 dots or more.

  Next, in FIG. 12, a case where recording is performed without thinning out two-dimensional codes for four rows of data code words and thinning out according to the present invention will be described. (Note that in this figure, the transport direction is the opposite of the previous figure.)

One element 141 corresponding to one module is assumed to be a standard-sized cell, and the recording resolution of the recording head is set to 600 [dpi]. As already described, the dot configuration of one element is as follows: width: 5 dots, height: 6 dots, and FIG. 12A shows the case without thinning. If the sheet has high penetrability inside, a two-dimensional code may be formed without thinning out in this way.

  Next, when the rear end side of the black cell region along the carrying direction (the right end in the example of FIG. 12) and the lower end side perpendicular to the black cell region are drawn for each one dot width, FIG. Thus, the thickness of the boundary between the black cell region and the white cell region can be corrected while maintaining continuity between adjacent elements in both the width direction and the height direction.

  Subsequently, when the downstream side of all modules (that is, each cell) and the side perpendicular to the module (the side at the lower end in the figure) are drawn for each one dot width, as shown in FIG. A theoretical gap is formed between adjacent elements in the width direction and height direction of each module (black cell). However, although the gaps on these dot patterns depend on the paper to be recorded, it is assumed that the gaps are actually inconspicuous with the naked eye due to ink bleeding. Further, the thickness of the black cell due to bleeding can be corrected by thinning out at the boundary between the black cell and the white cell. This is nothing but correction of thinning of white cells.

  The preferred embodiments of the present invention have been described above, but various modifications and changes other than those mentioned above can be made.

  In addition to the computer program for realizing the functions described in the above embodiments by a computer, a recording medium storing this program in a computer-readable manner is also included in the present invention. Examples of the “recording medium” for supplying the program include a magnetic storage medium (flexible disk, hard disk, magnetic tape, etc.), an optical disk (magneto-optical disk such as MO and PD, CD, DVD, etc.), semiconductor storage, and paper tape. And so on.

DESCRIPTION OF SYMBOLS 10 ... Inkjet recording device 12 ... Host computer 22K1-22K6 ... Recording head 24 ... Roll paper supply unit 26 ... Conveyance mechanism 60 ... Thinning pattern 61 ... Linear part 62 ... Side 102 ... Interface controller 106 ... Image memory 111 ... Tip detection sensor 112: Printhead control circuit 401 ... Main ink droplet 402 ... Satellite (secondary droplet)

Claims (13)

  Generated to print a two-dimensional code consisting of black cells and white cells on a print medium conveyed relative to the recording head by a recording head having a nozzle array consisting of a plurality of nozzles each ejecting ink In the two-dimensional code generation system, the two-dimensional code generation system is characterized in that the downstream side of each black cell is thinned out with a width of at least one dot.   A thinning pattern table storing a thinning pattern for thinning at least one dot width on the downstream side in the transport direction of each cell of the image area constituting the two-dimensional code, and applying the thinning pattern to the image of the two-dimensional code; The two-dimensional code generation system according to claim 1, wherein thinning processing is performed. Means for detecting the size of the cell;
2. The two-dimensional code generation system according to claim 1, further comprising: thinning means for thinning out a predetermined number of dots at a constant interval corresponding to the size of the cell in the transport direction in the image area of the two-dimensional code.   The number of dots of the width of the downstream side is determined according to at least one of the type of print medium to be used, the head temperature, the environmental temperature, the conveyance speed, and the size of the two-dimensional code. The two-dimensional code generation system in any one of -3.   5. The two-dimensional code generation system according to claim 1, wherein a side perpendicular to the side of each black cell is thinned out with a width of at least one dot.   6. When printing the two-dimensional code, an image is formed by passing the print medium once under the print head relative to the recording head. The described two-dimensional code generation system.   The two-dimensional code generation system according to any one of claims 1 to 6, wherein one or a plurality of recording dots are left every other dot or every plural dots in the longitudinal direction of the thinning target side.   Generated to print a two-dimensional code consisting of black cells and white cells on a print medium conveyed relative to the recording head by a recording head having a nozzle array consisting of a plurality of nozzles each ejecting ink A two-dimensional code generation program for causing a computer to execute a step of thinning out the downstream side of each black cell in the transport direction by at least one dot width.   Using a thinning pattern table storing a thinning pattern that thins out the downstream side in the transport direction of each cell of the image area constituting the two-dimensional code with a width of at least one dot, and applies this thinning pattern to the image of the two-dimensional code The two-dimensional code generation program according to claim 8, which causes a computer to execute a step of performing a thinning process by using a computer. Detecting the size of the cell;
9. The two-dimensional code according to claim 8, wherein the computer executes a step of thinning out a predetermined number of dots at a constant interval corresponding to the size of the cell in the transport direction in the image area of the two-dimensional code. Generation program.   10. The two-dimensional code generation program according to claim 8 or 9, wherein one or a plurality of recording dots are left every other dot or every plural dots in the longitudinal direction of the thinning target side. In a recording apparatus for printing a two-dimensional code composed of black cells and white cells on a print medium conveyed relative to the recording head by a recording head having a nozzle row composed of a plurality of nozzles each ejecting ink ,
An ink jet recording apparatus characterized in that the downstream side of each black cell is thinned out with a width of at least one dot.   13. The ink jet recording apparatus according to claim 12, wherein one or a plurality of recording dots are left every other dot or every plural dots in the longitudinal direction of the thinning target side.