JP2013107207A - Liquid ejecting apparatus and liquid ejection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid ejecting apparatus or the like performing a flushing operation on an ejection receiving medium and capable of causing a flushing region of the ejection receiving medium to be inconspicuous so that the quality of another region is not deteriorated.SOLUTION: A liquid ejecting apparatus includes a head part ejecting liquid of multiple colors from nozzles to form dots on an ejection receiving medium and a control part controlling the head part. The control part controls the head part so that a flushing image formed on the ejection receiving medium by the dots has inconspicuous color when executing a flushing operation of the nozzles by ejecting the liquid to the ejection receiving medium.

Description

  The present invention relates to a liquid ejection apparatus that performs a flushing operation on a medium to be ejected, and in particular, a liquid ejection apparatus that makes a flushing area of a medium to be ejected inconspicuous and does not impair the quality of other areas. Etc.

  Conventionally, a liquid ejection apparatus such as an ink jet printer has been used. In the liquid ejection apparatus, normally, a liquid is ejected (ejected) from a nozzle onto a medium to be ejected, and a predetermined process is executed. In the case of an ink jet printer, printing is executed by discharging ink of each color, which is a color material, from a plurality of nozzles provided in the head onto a printing medium such as paper.

  In such a liquid ejecting apparatus, if the nozzle is not used and the state in which the liquid is not ejected continues, the liquid in the vicinity of the nozzle thickens or adheres due to drying, and the ejection of the liquid becomes unstable or instable. May be possible.

  For this reason, normally, in an inkjet printer or the like, a flushing operation for periodically ejecting ink from each nozzle is performed as one of the cleaning operations for ensuring good ink ejection from the nozzles.

  In the flushing operation, when the head including the nozzle can be easily retracted from the normal processing position, the head is moved to the flushing operation position so as to absorb or collect the ink ejected by the flushing. Done. However, in the case of a so-called line head type that is long and does not have a moving mechanism, a flushing operation is performed at a normal processing position. In other words, in the case of a printer, ink is ejected by a flushing operation on a medium to be ejected. Further, in the case of continuous printing, a flushing operation must be performed in the process, and a flushing operation to the paper is performed.

  In the following Patent Document 1, an invention for suppressing printing defects in a printer that performs such a flushing operation is described, and in a flushing image formed by the flushing operation, ink ejected from nozzles does not overlap each other. Etc. are shown.

JP 2003-159785 A

  However, as described in Patent Document 1, in the conventional flushing operation on the medium to be ejected, a flushing pattern formed so as not to overlap a plurality of dots for each color for the purpose of determining the quality of the nozzles ( The flashing area was clearly colored.

As described above, if a flushing image that is colored and has a characteristic pattern is formed between the print areas, the quality of the printed matter is impaired, and it is difficult to distinguish the print area from the print area. Therefore, it is desired to make the flushing image as inconspicuous as possible.

  Accordingly, an object of the present invention is a liquid ejection apparatus that performs a flushing operation on a medium to be ejected, and can make the flushing area of the medium to be ejected inconspicuous so as not to impair the quality of other areas. It is to provide a liquid ejection device and the like.

  In order to achieve the above object, according to one aspect of the present invention, a liquid ejecting apparatus ejects a plurality of colors of liquid from a nozzle to form dots on a medium to be ejected, and controls the head unit. A flushing image formed on the ejection target medium by the dots when performing the flushing operation of the nozzle by ejecting the liquid onto the ejection target medium. Is to control the head section so that the image is less noticeable in color.

  Further, in the above invention, a preferred aspect is characterized in that the control unit controls the head unit so that the flushing image is an image having a uniform number of dots of a plurality of colors per unit area. .

  Further, in the above invention, one aspect is that the control unit controls the head unit so that the same number of consecutive dots as the number of colors of the plurality of colors includes the dots of the plurality of colors in the flushing image. It is characterized by.

  Further, in the above invention, another aspect is characterized in that the control unit controls the head unit so that the flushing image is an image in which dots of a plurality of colors are randomly arranged. .

  Still further, in the above invention, another aspect is characterized in that the control unit controls the head unit so that the flushing image becomes an image in which dots of a plurality of colors overlap each other at a predetermined position. .

  Furthermore, in the above invention, a preferred aspect is characterized in that the control unit controls the head unit so that dots smaller than other regions are formed in an end region of the flushing image. .

  Furthermore, in the above invention, another aspect is characterized in that the control unit controls the head unit so that the concentration of the liquid is lower in the end region of the flushing image than in other regions. And

  In order to achieve the above object, another aspect of the present invention provides a liquid ejection method in a liquid ejection apparatus including a head unit that ejects liquids of a plurality of colors from nozzles to form dots on a medium to be ejected. When performing the flushing operation of the nozzle by ejecting the liquid onto the ejection target medium, the number of dots of a plurality of colors per unit area is uniform in the flushing image formed on the ejection target medium by the dots. It is to make the image of.

  Further objects and features of the present invention will become apparent from the embodiments of the invention described below.

1 is a configuration diagram according to an embodiment of a liquid ejection apparatus to which the present invention is applied. 3 is a diagram illustrating a schematic arrangement of a head unit 23 of the printer 2. FIG. It is the figure which showed an example of the flushing image by a 1st method. It is the figure which showed another example of the flushing image by a 1st method. It is the figure which showed an example of the flushing image by a 2nd method. It is the figure which illustrated the flushing image containing the characteristic in an edge area. It is the figure which illustrated the flushing image containing the characteristic in an edge area.

  Embodiments of the present invention will be described below with reference to the drawings. However, such an embodiment does not limit the technical scope of the present invention. In the drawings, the same or similar elements are denoted by the same reference numerals or reference symbols.

  FIG. 1 is a configuration diagram according to an embodiment of a liquid ejection apparatus to which the present invention is applied. The printer 2 shown in FIG. 1 is a liquid ejection apparatus according to the present embodiment. When the flushing operation is performed on the paper 26, which is a medium to be ejected, control is performed so that the formed flushing area is achromatic. In order to prevent the quality of the print area from being impaired. An achromatic color means a color with zero saturation expressed by a mixed color of white and black. Here, the achromatic color is expressed by black with black ink or composite black with a plurality of inks, and does not include transparency.

  A host computer 1 shown in FIG. 1 is a host device of the printer 2 that gives a print instruction to the printer 2, and is composed of, for example, a personal computer. Therefore, although not shown, the host computer 1 includes a CPU, RAM, ROM, HDD, display, operation device, and the like.

  The application 11 is a print request source, and there may be applications having various functions such as a text creation application and a graphic creation application. The application 11 includes a program that instructs processing contents, the CPU that executes processing according to the programs, the RAM, and the like, and outputs image data representing the printing contents when a print request is made.

  The driver 12 is a driver for the printer 2, performs image processing on the image data output from the application 11 to obtain image data (print data) for the printer 2, sends the print data to the printer 2, and This is a part that issues a print instruction for printing requested by the application 11. The print data to be transmitted to the printer 2 is expressed by a command for the printer 2, and here, as an example, data after so-called screen processing expressing ON / OFF of each dot (for example, large, medium, and small dots) It has become.

  Further, the driver 12 transmits flushing data for the flushing operation to the printer 2 at a predetermined timing such as during a printing process in order to cause the printer 2 to perform a flushing operation for maintaining good ink ejection from the nozzles in the printer 2. can do. Note that the flushing data used at this time may be generated in advance or may be generated at a necessary timing. Further, when the function of the flushing operation is provided on the printer 2 side, the driver 12 does not need to have the function.

  The flushing data is basically in the same format as the image data at the time of normal printing. When the flushing operation is instructed, the print data including the flushing data is transmitted to the printer 2.

The driver 12 includes a driver program stored in the HDD and the like, flushing data for the flushing operation, the CPU that executes processing according to the driver program, the RAM, and the like. . The driver program and the flushing data for the flushing operation are copied from a storage medium such as a CD to the host computer 1 or downloaded to the host computer 1 via a network such as the Internet. Can be stored in one HDD.

  The printer 2 (liquid ejection device) is, for example, a line head type ink jet printer that executes a printing process in accordance with a printing instruction from the host computer 1. The printer 2 is a type of printer that performs printing on the roll paper 25.

  As shown in FIG. 1, the printer 2 includes a controller unit 21 and a print execution unit 22. The controller unit 21 (the control unit of the liquid ejection apparatus) is a part that receives print data according to the print instruction and causes the print execution unit 22 to execute print processing according to the print data. Specifically, control of the head unit 23 of the print execution unit 22, that is, control related to ink ejection, and control of the conveyance system of the print execution unit 22, that is, control related to conveyance of the paper 26 are performed.

  In addition, the controller unit 21 controls the head unit 23 so as to execute a flushing operation for maintaining good ink ejection from the nozzles in the head unit 23. As described above, when print data for a flushing operation instruction is transmitted from the driver 12 of the host computer 1, the flushing operation is executed according to the print data. On the other hand, when the controller unit 21 determines and executes the flushing operation, the flushing operation stored in the controller unit 21 is used to cause the head unit 23 to execute the flushing operation at a predetermined timing. In this case, the flushing data may be generated in advance, or may be generated by the controller unit 21 at a necessary timing.

  As described above, the flushing data is in the same format as the print data at the time of the normal printing. However, the data and the flushing image formed by the data have the characteristics of the apparatus, and the specific details thereof are as follows. Details will be described later.

  Specifically, the controller unit 21 includes a program describing processing contents, a CPU that executes processing according to the program, a RAM, a ROM that stores the program, an ASIC that is a logic circuit, and the like.

  Next, as described above, the print execution unit 22 includes an ink ejection system and a paper conveyance system (conveyance unit). In the paper transport system, a paper feed roller 27 that supplies the paper 26 held as the roll paper 25 to the transport path, a transport roller 28 that transports the supplied paper 26 to the printing position, and the paper 26 after printing to the outside of the apparatus. A paper discharge roller 29 and the like are provided, and the paper 26 is conveyed at a constant speed during the printing process. Although not shown, the paper transport system is provided with a driving device for each roller, a position detection device, and the like in addition to these.

  The ink ejection system includes a platen 24 and a head portion 23 positioned thereon. The head unit 23 is a so-called line head that includes a plurality of nozzles that discharge ink (liquid) that is a color material to the paper 26 (a medium to be discharged). Here, as an example, CMYK (cyan, magenta, yellow, black) four-color ink is used. The line head is divided into a plurality of head units (231a-c), and these are arranged in a staggered manner. The head unit performs printing processing by ejecting ink onto the paper 26 conveyed at a fixed speed by the paper conveyance system at a fixed position.

FIG. 2 is a diagram illustrating a schematic arrangement of the head unit 23 of the printer 2. Here, the head part 23 is divided into three head units 231a, 231b, 231c,
As shown in FIG. 2, they are arranged in a staggered manner with respect to the transport direction (arrow a in the figure) of the paper 26 that is the printing medium.

  Each head unit includes four nozzle rows 232, and each nozzle row 232 includes a plurality of (here, 360) nozzles. The nozzle rows 232 are configured to eject KCMY inks in order from the left in each nozzle unit. That is, the leftmost nozzle row 232 ejects K-color ink from the nozzles, the right-hand nozzle row 232 ejects C-color ink from the nozzles, and the right-next nozzle row 232 ejects M-color inks from the nozzles. In the rightmost nozzle row 232, Y-color ink is ejected from the nozzles.

  Therefore, for each color, 1080 nozzles are provided in this example. Then, as shown in FIG. 2, the adjacent head units are arranged so as to partially overlap in the width direction of the paper 26, and in the overlap portion indicated by b in FIG. Two nozzles are arranged at the same position (can eject ink with two nozzles).

  At the time of printing, ink of each color is ejected from each nozzle of such an arrangement provided in the fixed head unit with respect to the paper 26 moving in the transport direction.

  2 is a printing area on the paper 26, and an area d in FIG. 2 is a flushing area on the paper 26. The print area is a portion where a normal printing process is executed, and the flushing area is a portion where a flushing image is formed by a flushing operation. When the paper 26 is a continuous paper with no separation, the printing area can be made variable according to the contents of the printing process, the flushing area can be formed at an arbitrary position, and the size thereof can be arbitrarily selected. . On the other hand, when the paper 26 is for a die-cut label, the flushing operation is preferably performed on a non-labeled mount, and therefore the size and position of the print area and the flushing area are predetermined. Such print area (c) and flushing area (d) exist continuously on the paper 26.

  In the host computer 1 and printer 2 having the configuration described above, the printing process is executed as follows. First, when the application 11 issues a print request in the host computer 1, the image data is received by the driver 12. Thereafter, the driver 12 performs various types of image processing on the received image data. Specifically, first, rasterization processing is performed on image data expressed in units of objects, and the received image data is converted into bitmap data having a density gradation value of each color for each pixel. Next, color conversion processing for converting the color representation of the bitmap data into the color representation of the color material used in the printer 2 is executed. Specifically, for example, data expressed in RGB (red, green, blue) is converted into data expressed in CMYK. Next, after correction processing depending on the apparatus of the printer 2 is performed on the bitmap data, image data indicating ON / OFF of dots (for example, large, medium, and small dots) is obtained by screen processing.

  After the image processing is performed in this way, the driver 12 generates print data for a print instruction including the processed image data. The print data is expressed by a command for the printer 2 and includes various information related to printing such as the type of paper to be used.

  The print data is transmitted from the driver 12 to the printer 2 and received by the controller unit 21. The controller unit 21 interprets the received print data, and sequentially instructs the print execution unit 22 to execute print processing according to the result.

  In accordance with the instruction, the paper conveyance system of the print execution unit 22 moves the paper 26 to a predetermined position and then conveys the paper 26 at the constant speed described above until the printing process is completed. The head unit 23 of the print execution unit 22 discharges ink from each nozzle in the nozzle row 232 of each nozzle unit 231 in accordance with the above instruction. Specifically, based on the data indicating ON / OFF of the dot, whether or not ink is discharged from the nozzle at the position where the dot is formed is determined, and the ink discharge is executed.

  Thereafter, when the instructed print processing is completed, the printed portion 22 is cut and discharged from the printer 2 by the print execution unit 22 according to an instruction from the controller unit 21.

  Next, processing when executing the flushing operation will be described. Here, a case where the above-described flushing data for flushing is held on the driver 12 side and the driver 12 instructs the flushing operation will be described.

  First, the driver 12 determines execution of the flushing operation according to a predetermined timing. Then, in order to execute the flushing operation between normal print processes, the above-described print data for the flushing operation is generated and transmitted to the printer 2 between normal print data transmissions.

  The printer 2 receives the transmitted print data for the flushing operation, and executes print processing according to the print data as in the case of the normal printing described above. That is, the paper conveyance system and the head unit 23 of the print execution unit 22 operate according to instructions from the controller unit 21, ink is ejected from each nozzle according to the flushing data for the flushing, and a flushing image is displayed in the flushing area of the paper 26. It is formed. That is, ink is ejected from all the nozzles to improve ink ejection.

  When the flushing data is held or generated on the printer 2 side, the controller unit 21 reads or generates the flushing data at a predetermined timing based on an instruction from the driver 12 or a determination by the controller 21, and The flushing operation using the flushing data is performed by causing the head unit 23 to execute the flushing operation in the same manner as described above.

  Next, the above-described flushing data for flushing and the flushing image formed by the flushing data will be described.

  The flushing image formed by the printer 2 is an image in which colors are not conspicuous, and is particularly characterized by being formed in an achromatic color. Therefore, the flushing area of the paper 26 described above is not colored.

  Specifically, several methods can be used. In the first method, the color of the dots per unit area in which the color of the dots in the flashing image to be formed cannot be visually distinguished can be used. Flushing data that makes the number of dots uniform is used.

  One specific example is that in the flushing image, dots of all ink colors are included in the same number of dots arranged in the transport direction of the paper 26 or in the direction orthogonal thereto.

FIG. 3 is a diagram illustrating an example of a flushing image according to the first technique. FIG. 3A shows the flushing region d1 in the case of the above-described specific example, and the portion painted black indicates the flushing image. In the drawing, e1a, e1b, and e1c are formed by the nozzles of the head units 231a, 231b, and 231c, respectively. Here, 100 dots are formed for each nozzle row 232 (100 times of ink ejection). Since the dots are not overlapped, the width of the flushing region d1 (the length in the horizontal direction in the figure) is 800 dots.

  FIG. 3B is an enlarged view of a part of the flushing image, and each circle (such as f1) indicates a dot. Each dot display pattern indicates a color, and expresses CMYK.

  The example shown here is a flushing image in which dots of each color are arranged in a certain order in the conveyance direction of the paper 26, and as in the area indicated by g1 in the figure, the number of dots is the same as the number of inks arranged in the conveyance direction. They are arranged so as to include dots of all ink colors (four colors). With such an arrangement, the number of dots of each color per unit area can be made uniform. Note that the image shown in FIG. 3 is merely an example, and four colors of dots can be included in four dots by other arrangements.

  Another specific example of the first method is to randomly arrange dots of each color in the flushing image. FIG. 4 is a diagram showing another example of the flushing image by the first method. The expression format of the flushing image in FIG. 4 is the same as that in FIG. 3, and the sizes of the flushing images e2a, e2b, e2c and the flushing region d2 formed by each head unit 231 are the same as in FIG.

  In this specific example, as shown in FIG. 4B, dots of each color (such as f2) are randomly arranged, and the number of dots of each color per unit area is substantially uniform. A random number can be used when generating the flushing data for the flushing image.

  Next, the second method is to use a flushing data in which a plurality of dots (a plurality of ink ejections) are overlapped at the same position so that the dots themselves in the flushing image become achromatic. One specific example of this technique is to eject four colors of ink at the same position once.

  FIG. 5 is a diagram illustrating an example of a flushing image according to the second technique. The expression format of the flushing image in FIG. 5 is the same as that in FIG. 3, but here, since a plurality of dots are overlapped, the flushing image e3 and the flushing region d3 are smaller than those in FIGS. In the example shown in FIG. 5, as in the case of FIGS. 3 and 4, dots of 100 columns of each color are formed. Become.

  As shown in FIG. 5B, in this example, since the four colors of ink are ejected once at the same position as described above, each dot (such as f3) becomes achromatic by mixing CMYK. . Thereby, it is realized that the dots of the flushing image themselves are achromatic. Further, since the dots are overlapped, the flushing area can be reduced, and the flushing image can be made inconspicuous even in terms of size.

  Also in the second method, the above-described flushing image is an example, and other images in which the dots themselves are achromatic may be used.

Next, a technique that can be performed at the end of the flushing image (end in the transport direction of the paper 26) will be described. This method can be used in the first method and the second method described above. One specific example is to arrange dots of achromatic ink (for example, black (K) ink) in the end region of the flushing image. Another specific example is that the size of the dots in the end region is smaller than the other regions of the flushing image.

  FIG. 6 is a diagram illustrating a flushing image including features in these end regions. The expression format of the flushing image in FIG. 6 is the same as that in FIG. 3, but FIG. 6B shows an enlarged display of the portion including the end region of the flushing image e4. The example shown in FIG. 6 uses the arrangement of the achromatic color ink and the small dots at the end described above, and is arranged in the end region (g4) as shown in FIG. 6B. The dots are K ink and are smaller than the dots (f4 etc.) in other areas. In the figure, h4 indicates the end position of the flushing image e4.

  In the end area of the flushing image, there is a risk that the end area may be colored due to ink bleeding or landing (discharge direction) misalignment. However, the end area can be prevented from being colored.

  Another specific example is to lower the ink density in the end region of the flushing image. FIG. 7 is a diagram showing an example thereof. The expression format of the flushing image in FIG. 7 is the same as that in FIG. In the example shown here, as shown in FIG. 7B, printing is performed with a lower density than the other areas in the end region g5 of the flushing image e5 with h5 as the end. In other words, the dots in other areas (such as f5) are formed from a plurality of dots, whereas the dots in the end region g5 are formed from one dot.

  Also in such an example, the amount of ink in the end region can be reduced, so that ink bleeding can be reduced and coloring in the end region can be prevented.

  As described above, in the liquid ejecting apparatus according to the present embodiment, in the flushing operation performed on the ejection target medium (paper 26), the flushing image formed becomes achromatic, the flushing area becomes inconspicuous, and the printing area The quality of the product can be prevented from being lost as much as possible.

  Further, the achromatic color can be realized by making the number of dots of each color per unit area uniform in the flushing image. Further, as a specific method, by arranging dots of each color at random, coloring can be prevented even if there is a slight landing deviation.

  Further, the achromatic color can be more reliably realized by achromatic the dots of the flushing image.

  Further, by superimposing dots of each color in the flushing image, the flushing area can be made smaller for the same number of ink ejections, and the area can be made less noticeable.

  Furthermore, by adding the features in the end region of the flushing image described above, coloring in the end region can be prevented, and prevention of coloring of the flushing image can be more reliably performed.

  The present invention can be applied not only to a printer but also to a similar liquid ejection apparatus.

  The protection scope of the present invention is not limited to the above-described embodiment, but covers the invention described in the claims and equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 Host computer, 2 Printer, 11 Application, 12 Driver, 21 Controller part, 22 Print execution part, 23 Head part, 24 Platen, 25 Roll paper, 26 Paper, 27 Paper feed roller, 28 Transport roller, 29 Paper discharge roller, 231a-c head unit, 232 nozzle array

Claims (8)

A head unit that ejects liquids of a plurality of colors from the nozzles to form dots on the ejection target medium, and a control unit that controls the head unit,
When the controller performs the flushing operation of the nozzle by ejecting the liquid onto the ejection target medium, the flushing image formed on the ejection target medium by the dots becomes an image in which the color is not conspicuous. As described above, the liquid ejecting apparatus is characterized in that the head unit is controlled. In claim 1,
The liquid ejecting apparatus, wherein the control unit controls the head unit so that the flushing image is an image having a uniform number of dots of a plurality of colors per unit area. In claim 2,
The liquid ejecting apparatus, wherein the control unit controls the head unit so that the same number of consecutive dots as the number of colors of the plurality of colors includes the dots of the plurality of colors in the flushing image. In claim 2,
The liquid ejecting apparatus, wherein the control unit controls the head unit so that the flushing image is an image in which dots of a plurality of colors are randomly arranged. In claim 1,
The liquid ejecting apparatus, wherein the control unit controls the head unit so that the flushing image becomes an image in which dots of a plurality of colors overlap at a predetermined position. In any one of Claims 1 thru | or 5,
The liquid ejection apparatus, wherein the control unit controls the head unit so that dots smaller than other regions are formed in an end region of the flushing image. In any one of Claims 1 thru | or 6,
The liquid ejecting apparatus according to claim 1, wherein the control unit controls the head unit so that the concentration of the liquid is lower in an end region of the flushing image than in other regions. A liquid discharge method in a liquid discharge apparatus including a head unit that discharges a plurality of colors of liquid from a nozzle to form dots on a discharge target medium,
When performing the flushing operation of the nozzle by ejecting the liquid onto the ejection target medium, the flushing image formed on the ejection target medium by the dots has a number of dots of a plurality of colors per unit area. A liquid discharge method characterized by forming a uniform image.