JP2013067093A - Ink jet recording apparatus, and recording control method in the ink jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording apparatus that records a bar code which prevents degradation in reading accuracy.SOLUTION: In the ink jet recording apparatus in which the bar of a bar code is recorded in the form of a plurality of lines of recorded dots, recording is controlled so that recorded dots are thinned out in each of the lines of recorded dots. In this case, recording is controlled so that the thinning-out rate of a line of recorded dots adjacent to a line of recorded dots located at an outer edge among the plurality of lines of recorded dots is the highest among the plurality of lines of recorded dots.

Description

  The present invention relates to an inkjet recording apparatus that records a barcode on a recording medium, and a recording control method in the inkjet recording apparatus.

  Conventionally, various methods such as a wire dot method, a thermal method, a thermal transfer method, and an ink jet recording method are known as a recording method of a recording apparatus that records on a recording medium. Among them, the ink jet recording method is widely used because of its advantages such as non-contact recording on a recording medium, low running cost, easy colorization, non-impact method and high quietness.

  Such an ink jet recording apparatus is often used not only for printing ordinary documents but also for printing shelf display labels, bar codes, tags, and the like. Bar codes printed with an ink jet recording apparatus must be read accurately, and therefore must meet certain standards and accuracy. For example, the ratio between the bar width and the space width constituting the barcode must be within a certain standard range.

  The ink droplets ejected from the nozzles of the ink jet recording apparatus form circular recording dots when landing on the recording medium. The diameter of the recording dots formed on the recording medium is slightly larger than the nozzle pitch of the recording head and the pixel pitch of the image so that the adjacent recording dots overlap sufficiently even if there is a slight landing deviation or variation in the discharge amount. Larger is desirable.

  However, when recording dots are formed in this way, the bar width of the bar code is large and the space width is narrow, resulting in unevenness. As a result, even if the ratio between the bar width and the space width deviates from the standard value or falls within the standard value, the reading accuracy is lowered.

  In Patent Document 1, recording dots other than the outer periphery are controlled by controlling a drive pulse applied to a heating element for a part or all of the recording dots constituting the outer periphery of the cell among the recording dots constituting the cell of the two-dimensional code. It describes that the recording is controlled so as to be smaller than a dot.

JP 2003-237059 A

  However, in Patent Document 1, there is a possibility that the behavior of ink ejection becomes unstable when the drive pulse is controlled. As a result, it is conceivable that the landing position of the ink droplet becomes unstable, and the code reading accuracy is rather lowered.

  An object of the present invention is to solve such conventional problems. In view of the above points, an object of the present invention is to provide an ink jet recording apparatus that records a barcode that prevents a decrease in reading accuracy, and a recording control method in the ink jet recording apparatus.

  In order to solve the above problems, an ink jet recording apparatus according to the present invention includes a recording unit that records each bar included in a barcode with a plurality of recording dot rows, and thins out recording dots in each of the plurality of recording dot rows. Recording control means for controlling the recording means, the recording control means, for each bar, the recording dot row adjacent to the recording dot row located on the outer edge of the plurality of recording dot rows, The recording means is controlled so that the thinning rate is highest among a plurality of recording dot rows.

  According to the present invention, it is possible to record a barcode that prevents a decrease in reading accuracy.

It is a figure which shows the structure of an inkjet recording device. 2 is a diagram illustrating a configuration of a control system of the inkjet recording apparatus 10. FIG. It is a figure which shows an example of the structure of recording data. It is a figure which shows an example of the barcode recorded on the recording medium. It is a figure for demonstrating bar width and space width based on a nozzle pitch. It is a figure explaining the blur of a recording dot. It is a figure for demonstrating dividing a bar part into three. It is a figure for demonstrating a density control process. It is a figure which shows the effect by a density control process. It is a flowchart which shows the procedure of a density control process. It is a flowchart which shows the procedure from reception of recording data to printing.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the following embodiments do not limit the present invention according to the claims, and all combinations of features described in the present embodiments are not necessarily essential to the solution means of the present invention. . The same constituent elements are denoted by the same reference numerals, and the description thereof is omitted.

[Configuration of Inkjet Recording Apparatus]
FIG. 1 is a diagram illustrating a configuration of an ink jet recording apparatus according to the present embodiment. The ink jet recording apparatus 10 is communicably connected to the host computer 12 via a network. The ink jet recording apparatus 10 records on the recording medium P by ejecting ink from the recording head 22K, the recording head 22C, the recording head 22M, and the recording head 22Y based on the recording data transmitted from the host computer 12. Although four recording heads are shown in FIG. 1, recording heads corresponding to other inks such as special color inks may be further mounted.

  The four recording heads 22K, the recording head 22C, the recording head 22M, and the recording head 22Y are arranged along the conveyance direction of the recording medium P (the direction of arrow A in the figure). Each recording head is arranged in the order of the recording head 22K, the recording head 22C, the recording head 22M, and the recording head 22Y from the upstream in the transport direction. Each recording head is a line type recording head, and is arranged in parallel over the entire recording width with respect to the recording medium conveyance direction. The ink jet recording apparatus 10 performs recording by conveying the recording medium P without moving each recording head. Further, the ink jet recording apparatus 10 performs recording by driving a heater on the recording head and discharging ink from the nozzles onto the recording medium.

  When recording is performed, foreign matters such as dust and ink droplets may adhere to the nozzle surface 22Ks, nozzle surface 22Cs, nozzle surface 22Ms, and nozzle surface 22Ys of each recording head. In this case, the ink ejection state may change and affect recording. A recovery device 40 is configured in the ink jet recording apparatus 10 so that ink can be stably ejected from each recording head. Since the recovery device 40 periodically cleans the nozzle surfaces, the ink ejection state from the nozzles of each recording head can be maintained satisfactorily. The recovery device 40 is provided with a cap 50 that is opposed to the nozzle surface of each recording head and removes ink remaining on each nozzle surface. The cap 50 is provided independently of each recording head, and includes a blade (not shown), an ink removing member, a blade holding member, a cap, and the like.

  The recording medium P, which is roll paper, is supplied from the roll paper supply unit 24 and is transported in the direction of arrow A by the transport mechanism 26. The transport mechanism 26 includes a transport belt 26a for placing and transporting the recording medium P, a transport motor 26b for rotating the transport belt 26a, and a roller 26c for applying tension to the transport belt 26a. . When the recording medium P being conveyed at the time of recording reaches the lower portion of the recording head 22K, black ink is ejected from the recording head 22K onto the recording medium P based on the recording data transmitted from the host computer 12. Subsequently, color recording is performed by ejecting each color ink onto the recording medium P in the order of the recording head 22C, the recording head 22M, and the recording head 22Y.

  The ink jet recording apparatus 10 includes an ink tank 28K, an ink tank 28C, an ink tank 28M, an ink tank 28Y for storing ink to be supplied to each recording head, a pump for replenishing each recording head with ink, and a cleaning operation. It includes a pump and so on.

  FIG. 2 is a diagram illustrating a configuration of a control system of the inkjet recording apparatus 10. When recording data having a structure as shown in FIG. 3 is transmitted from the host computer 12 to the inkjet recording apparatus 10, the recording data is stored in the image memory 203K for black ink, the image memory 203C for cyan ink, and magenta. Drawing is developed on each of 203M for ink and 203Y for yellow ink. Here, for example, the recording data is recording data representing a document image.

  When the barcode data is present in the recording data transmitted from the host computer 12 (for example, when the barcode is included in the document image), the recording data representing the barcode is bitmapped in the image memory 203K for black ink. Draw and expand as data. At this stage, the ratio between the bar width and the space width of the barcode is set by the user so as to be within the standard range. In this embodiment, the bar portion of the bar code is divided into a plurality of sections, and the ink ejection is controlled so that the recording dot thinning rate (density) is different for each section. This control will be described later.

  When drawing development for four inks is completed for the entire recording data transmitted from the host computer 12, the main controller 201 drives a motor 26 b as a driving source for transporting the recording medium P by the motor driver 206. . The memory controller 204 sequentially reads the recording data drawn and developed from the image memories 203K, 203C, 203M, and 203Y in synchronization with the conveyance of the recording medium P, and reads the read recording data via the recording head drive circuit 205. Transfer to recording heads 22K, 22C, 22M and 22Y. The recording heads 22K, 22C, 22M, and 22Y supply a drive signal to the heater based on the transferred recording data, and perform recording by ejecting ink from the nozzles.

[Structure of recorded data]
FIG. 3 is a diagram illustrating an example of a structure of recording data transmitted from the host computer 12. As shown in FIG. 3, the recording data is largely composed of a start command 31, a content 35, and an end command 34. The start command 31 represents the print setting contents for the entire print area (for example, the entire document). In this example, the start command 31 includes, for example, an identification code for identifying the recording apparatus, a print reference position on the recording medium, an effective printing range in the recording medium, and the number of printed sheets. The content 35 includes, for example, an attribute unit 32 for setting the type and position of each field such as an image or a character included in the document, and a data unit 33 for storing actual data representing recorded contents. When the field type is a character (character), an identification code, font type, character size, character color, character decoration information, character spacing, and character rotation information are set in the attribute unit 32. When the field type is an image (image), an identification code, a vertical and horizontal size, an image type, and a drawing color are set in the attribute unit 32. When the field type is a barcode, an identification code, a barcode type, a magnification, a barcode height, and barcode rotation information are set in the attribute unit 32. The inkjet recording apparatus 10 can recognize that the barcode information exists by referring to the attribute portion 32 of the recording data transmitted from the host computer 12. The data portion 33 includes a data length and data representing contents. The end command 34 is composed of only an identification code and indicates the end of the recording data.

[Barcode configuration]
FIG. 4 is a diagram illustrating an example of a bar code recorded on a recording medium by the ink jet recording apparatus 10. FIG. 2A shows an example of a barcode recorded on a recording medium. FIG. 2B schematically shows the recording state of the recording dots constituting the bar of the barcode. In FIG. 2B, black circles indicate recording dots formed by the landing of ink droplets. In addition, for the sake of explanation, the white circle virtually positions the recording dot, but no ink droplet is actually ejected. As shown in FIG. 3, the nozzle pitch of the recording head is strongly reflected in the bar width and space width of the barcode recorded by the inkjet recording apparatus 10.

  FIG. 5 is a diagram for explaining the bar width and space width of a bar code based on the nozzle pitch. As shown in FIG. 5, the bar width Lb and the space width Ls between two bars having the bar width Lb are calculated by the following equations (1) and (2).

Lb = (Nozzle pitch) × (number of dots−1) + dot diameter (1)
Ls = (nozzle pitch) × (number of dots + 1) −dot diameter (2)
In general, a bar code needs to satisfy certain standards and accuracy in order to be read accurately. That is, it is necessary that the ratio between the bar width and the space width constituting the barcode is within a certain standard range. In particular, when printing a small barcode, the above ratio appears more prominently. Therefore, the bar width and space width are adjusted by the user on the host computer 12 for a bar having a large difference between the bar width and the space width, and the ratio is within the standard range. Controlled to fit.

  Here, a problem that occurs when printing a barcode in the inkjet recording apparatus 10 will be described. Ink droplets land on the recording medium to form recording dots. However, when a plurality of recording dots are adjacent to each other, as shown in FIG. 6, adjacent recording dots are connected and ink is present. The phenomenon of bleeding in the direction not to occur occurs. In other words, even if the control for adjusting the bar width is performed, the bar width may increase unexpectedly due to ink bleeding, and the ratio may be out of the standard range. Therefore, in this embodiment, the bar part of the bar code is divided into three parts, and the thinning rate of the recording dots in each part is made different. This prevents the bar width from becoming unexpectedly large even if the ink is smeared.

  FIG. 7 is a diagram for explaining the division of the bar portion into three portions. As shown in FIG. 7, in this embodiment, the end corresponding to the recording dot row located on the outer edge of each bar, the end adjacent portion adjacent to the end, and the bar sandwiched between the end adjacent portions Divide the bar into three parts with the inside. In the present embodiment, the density of the recording dots is made different in each of the end portion, the end adjacent portion, and the three portions inside the bar. Hereinafter, this control is also referred to as density control.

[Density control processing]
The density control in this embodiment will be described with reference to FIG.

  Attention is paid to one of a plurality of bars included in the barcode. In the present embodiment, the recording dot rows are processed in order from the left to the right in the figure with respect to the bar. First, as shown in FIG. 8A, at the end of the bar (in this case, the left end of the bar), every other recording dot is thinned out in order to maintain the linearity of the edge. That is, recording dots are not formed in every other row, but recording dots are formed every other row. Next, as shown in FIG. 8B, in the adjacent portion of the end of the bar, all the recording dots in one row are thinned out. That is, no recording dot is formed in the edge adjacent portion.

  Next, as shown in (c) of FIG. 8, the recording dots are randomly thinned out inside the bars of the third to ninth columns from the left. However, inside the bar, control is performed so that three or more dots are not continuously thinned out in the row direction. Next, as shown in (d) of FIG. 8, at the end portion adjacent portion in the tenth column from the left, as in (b) of FIG. Finally, as shown in FIG. 8E, every other recording dot is thinned out in the 11th column from the left, that is, at the right end of the bar, as in FIG. 8A.

  Such density control is based on the concept that the bar adjacent to the end of the bar serves as a so-called groove to prevent the ink from flowing out of the bar from flowing into the bar code space. FIG. 9 is a diagram conceptually showing the effect of the density control process in the present embodiment. FIG. 9A shows a case where density control is not performed, and FIG. 9B shows a case where density control is performed. Moreover, both FIG. 9 (a) and (b) has shown about two bars. In FIG. 9A, the ink from the inside of the bar oozes out into the space, and as a result, the space width is narrowed. The barcode shown in FIG. 9A may not be read normally. On the other hand, in FIG. 9B, since the ink ooze out from the inside of the bar is accumulated in the adjacent portion of the end portion, it does not ooze out to the space. That is, the accuracy of barcode reading can be maintained.

  FIG. 10 is a flowchart showing a procedure of density control processing (recording control method) executed in the inkjet recording apparatus 10. The process shown in FIG. 10 is executed by the memory controller 204, for example. Prior to the processing shown in FIG. 10, as described above, the host computer 12 adjusts the bar width and the space width, and sends the recording data describing the position of the barcode on the document to the inkjet recording apparatus 10. Is done. As described with reference to FIG. 2, the inkjet recording apparatus 10 draws and develops, as bitmap data, the portion representing the barcode in the recording data transmitted from the host computer 12 in the image memory 203 </ b> K for black ink. Thereafter, the process shown in FIG. 10 is performed.

  First, in S1001, the memory controller 204 pays attention to one bar in the barcode, and reads the recording dot row one row at a time from one direction for the bar. In S1002, the memory controller 204 determines whether or not the target line is the first line from the end of the bar. If it is determined that the current line is the first line, the process proceeds to S1003, where the edge density control process is performed, and the target line is shifted by one line after the process. The edge density control process in S1003 is the process described in FIG. On the other hand, if it is determined that it is not the first line, the process proceeds to S1004.

  In S1004, the memory controller 204 determines whether or not the target line is the second line from the end of the bar. If it is determined that the current line is the second line, the process advances to step S1005 to perform an edge adjacent portion density control process, and after the process, the target line is shifted by one line. The edge adjacent portion density control process in S1005 is the process described in FIG. On the other hand, if it is determined that it is not the second line, the process proceeds to S1006.

  In S1006, the memory controller 204 performs an internal density control process, and after the process, shifts the target line by one line. The internal density control process in S1006 is the process described in FIG. In S1007, the memory controller 204 determines whether or not the current target line is the Ni line. The Ni line corresponds to the ninth line in FIG. If it is determined that the line is Ni, the process proceeds to S1008. On the other hand, if it is determined that the line is not Ni, the process returns to S1006. That is, in S1006, the internal density control process is performed in the third line to the Ni line.

  In S1008, the memory controller 204 performs an edge adjacent portion density control process on the Ni + 1 line, and shifts the target line by one line after the process. The edge adjacent portion density control process in S1008 is the process described in FIG. In step S1009, the memory controller 204 performs an edge density control process on the Ni + 2nd line. The edge density control process in S1009 is the process described in FIG.

  As described above, the density control process is performed in the inkjet recording apparatus 10. Here, in the end adjacent portion, all the recording dots for one row are thinned out. However, if it is possible to obtain an effect that does not allow the ink inside the bar to bleed into the space, it is not necessary to thin out all the recording dots for one row. For example, the density control may be performed so that the relationship of the thinning rate of recording dots between the end portion, the end adjacent portion, and the inside of the bar satisfies the following expression (3).

Thinning rate of recording dots at end portion <Thinning rate of recording dots at adjacent end portion> Thinning rate of recording dots inside bar (3)
Further, in FIG. 8C, it has been described that the recording dots are controlled not to be thinned out continuously by 3 dots or more in the horizontal direction. If there is, for example, the continuous 5 dots may be set as the limit value.

  As described above, in this embodiment, it is possible to prevent the ink from bleeding into the space from the inside of the bar by making the thinning rate of the recording dots in the edge adjacent portion larger than the inside of the end and the bar. In this embodiment, the recording dots are thinned out even inside the bar. That is, if the recording dot thinning rate inside the bar is 0% (that is, no thinning), even if the thinning rate is 100% (that is, no recording dots are formed) at the edge adjacent portion, the ink bleeding from the inside of the bar The protruding amount cannot be absorbed in the adjacent portion of the end and overflows into the space. In the present embodiment, the absorption effect at the edge adjacent portion can be further improved by thinning out the recording dots even inside the bar.

  FIG. 11 is a flowchart illustrating a procedure of processing from when the inkjet recording apparatus 10 receives the recording data from the host computer 12 to printing described with reference to FIG. The process shown in FIG. 11 is executed by the main controller 201, for example. Further, S1106 is executed by the memory controller 204 according to an instruction to the main controller 201.

  First, in S1101, the main controller 201 receives and acquires recording data from the host computer 12, and in S1102, the recording data is analyzed. In step S1103, the main controller 201 determines whether there is barcode information in the recording data. If it is determined that there is barcode information, the process proceeds to S1105. If it is determined that there is no barcode information, the process proceeds to S1104.

In S1105 and S1104, the recording data is drawn and developed in the image memories 203K, 804C, 804M, and 804Y. However, after the process of S1105, the memory controller 204 performs the density control process as described with reference to FIG. 10 (S1106). After the processes in S1106 and S1104, the memory controller 204 reads the drawn and developed recording data from each image memory, and performs recording by ejecting ink from each recording head onto the recording medium.

DESCRIPTION OF SYMBOLS 10 Inkjet recording device 12 Host computer 22K, 22C, 22M, 22Y Recording head 22Ks, 22Cs, 22Ms, 22Ys Nozzle surface 26 Conveying mechanism 26a Conveying belt 26b Conveying motor 26c Roller 28K, 28C, 28M, 28Y Ink tank 40 Recovery device 50 Cap 201 Main controller 202 Memory 203Y, 203M, 203C, 203K Image memory 205 Recording head drive circuit 206 Motor driver

Claims (4)

Recording means for recording each bar included in the barcode with a plurality of recording dot rows,
A recording control means for controlling the recording means so as to thin out the recording dots in each of the plurality of recording dot rows;
The recording control unit is configured to increase the thinning rate of the recording dot row adjacent to the recording dot row located on the outer edge of the plurality of recording dot rows for each of the bars among the plurality of recording dot rows. And an ink jet recording apparatus for controlling the recording means.   2. The ink jet recording according to claim 1, wherein the recording control unit controls the recording unit so as to thin out all the recording dots included in the recording dot row adjacent to the recording dot row located on the outer edge. apparatus. Obtaining means for obtaining recorded data;
Determination means for determining whether or not the barcode is included in the image represented by the recording data acquired by the acquisition means;
The inkjet recording apparatus according to claim 1, further comprising: A recording control method executed in an inkjet recording apparatus including a recording unit that records a bar included in a barcode with a plurality of recording dot rows,
A recording control step of controlling the recording means so that the recording control means of the ink jet recording apparatus thins out the recording dots in each of the plurality of recording dot rows;
In the recording control step, the recording means is arranged so that a recording dot row adjacent to a recording dot row located at an outer edge among the plurality of recording dot rows is set to have the highest thinning rate among the plurality of recording dot rows. The recording control method characterized by controlling.

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