Image forming method and image forming apparatus

Abstract

To provide an image forming method which can suppress missing of a thin line or a character while suppressing protrusion of a white base from an upper layer.SOLUTION: An image forming method is provided that includes discharging, from a liquid discharged head, white ink and color ink onto a recording medium to form a first layer by the white ink and form a second layer by the color ink on the first layer. When the width of the second layer is equal to or smaller than a prescribed value, the width of the first layer is equal to the width of the second layer, and when the width of the second layer is larger than the prescribed value, the width of the first layer is smaller than the width of the second layer.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to an image forming method and an image forming apparatus. [Background technology]

[0002] Conventionally, there has been known an apparatus for forming an image by depositing a liquid such as ink onto a recording medium such as a cloth, etc. In such an apparatus, in order to allow the color ink to develop appropriately on the cloth, the cloth may be coated with white ink before the color ink is deposited.

[0003] However, when white ink is used as a base for color inks, the ejection positions of the white and color inks may become misaligned. Furthermore, if the ink bleeds, it may spill over into unintended areas, reducing image reproducibility. Furthermore, to ensure sufficient whiteness, white ink may be deposited in multiple inkjet heads, which increases the amount of ink ejected and makes it more susceptible to bleeding. Therefore, there is a need to control the spillover of white ink to improve image quality.

[0004] A conventional technique for preventing overflow is to narrow the area where the white ink that forms the base is ejected. For example, Patent Document 1 discloses that the printing area of ​​the base color is narrower than that of the upper layer in order to prevent overflow of the base color, and also discloses a configuration in which the area is not narrowed if the base does not function as a base. Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide an image forming method that can prevent thin lines and characters from being missing while preventing the white base from spilling out of the upper layer. [Means for solving the problem]

[0006] In order to solve the above problem, the image forming method of the present invention is an image forming method having an ejection step of ejecting white ink and color ink onto a recording medium using a liquid ejection head to form a first layer of the white ink and a second layer of the color ink on the first layer, wherein when the width of the second layer is equal to or less than a predetermined value, the width of the first layer is made the same as the width of the second layer, and when the width of the second layer is greater than the predetermined value, the width of the first layer is made smaller than the width of the second layer. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an image forming method that can prevent the white base from spilling out of the upper layer and prevent thin lines and characters from being missing. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a flowchart illustrating an example of an image forming method according to the present invention. [Figure 2A] FIG. 10 is a schematic diagram for explaining an example of a determination process. [Figure 2B] FIG. 10 is a schematic diagram for explaining another example of the determination process. [Figure 2C] FIG. 10 is a schematic diagram for explaining another example of the determination process. [Figure 3] 10A and 10B are diagrams illustrating an example of a method for calculating the minimum width of white. [Figure 4] 1A and 1B are diagrams illustrating an example of a character. [Figure 5] 4A and 4B are diagrams for explaining an example of a character, and are diagrams for explaining the details of FIG. 4B. [Figure 6] 10A and 10B are diagrams illustrating other examples of characters. [Figure 7] FIG. 7 is a diagram for explaining another example of characters, and is a diagram for explaining the details of FIG. 6(B). [Figure 8] 1 is a perspective view of an example of the configuration of an image assignment system according to an embodiment; [Figure 9] 1 is a perspective view of an example of the configuration of an image forming apparatus according to an embodiment; [Figure 10] 10 is a perspective view of the configuration example of the device as seen from a direction different from that of FIG. 9. FIG. [Figure 11] FIG. 2 is a diagram illustrating an example of the configuration of a carriage of an image forming apparatus according to an embodiment. [Figure 12] FIG. 2 is a block diagram illustrating an example of the hardware configuration of a control unit of the device. DETAILED DESCRIPTION OF THE INVENTION

[0009] The image forming method and image forming apparatus according to the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the following embodiments, and other modifications, additions, corrections, deletions, and other changes can be made within the scope of what a person skilled in the art can conceive. Any embodiment that achieves the functions and effects of the present invention is within the scope of the present invention.

[0010] The image forming method of the present invention is an image forming method having an ejection step of ejecting white ink and color ink onto a recording medium using a liquid ejection head to form a first layer of the white ink and a second layer of the color ink on the first layer, characterized in that when the width of the second layer is equal to or less than a predetermined value, the width of the first layer is made the same as the width of the second layer, and when the width of the second layer is greater than the predetermined value, the width of the first layer is made smaller than the width of the second layer.

[0011] Furthermore, one embodiment of the image forming method of the present invention includes a to-be-formed area calculation step of determining an area of ​​the second layer to be formed from image information and an area of ​​the first layer corresponding to the area of ​​the second layer to be formed, thereby determining a white width (1) to be discharged, a correction value acquisition step of acquiring a correction value for reducing the white width (1) to be discharged, and a determination step of determining a white discharge width to be discharged in the discharge step using the white width (1) to be discharged, the white lower limit width, and the correction value, where the predetermined value is a white lower limit width. In this case, the white lower limit width and the white width (1) to be discharged are lengths in the same direction, and the determination step determines the white discharge width by determining whether the white width (1) to be discharged is larger than the white lower limit width, and the discharge step discharges the white ink based on the white discharge width determined in the determination step.

[0012] The image forming apparatus of the present invention is an image forming apparatus that forms a first layer of white ink and a second layer of color ink on a recording medium, and is characterized in that when the width of the second layer is less than a predetermined value, the width of the first layer is made the same as the width of the second layer, and when the width of the second layer is greater than the predetermined value, the width of the first layer is made smaller than the width of the second layer.

[0013] One embodiment of the image forming apparatus of the present invention is an image forming apparatus that performs one embodiment of the image forming method of the present invention, and is characterized by comprising the liquid ejection head and a control unit that performs the planned formation area calculation process, the correction value acquisition process, and the determination process.

[0014] In conventional technology, when printing thin lines or small characters, the white background area is narrowed, resulting in the disappearance of the white background and missing lines or characters. In other words, the white background may be formed with a width smaller than the minimum required white width, resulting in a deterioration of image quality. Furthermore, the optimal background area is thought to vary depending on the color of the recording medium and the color of the lines and characters printed on the background, but conventional technology was unable to address this issue.

[0015] The minimum required white width also varies depending on the relationship between the color of the recording medium and the color of the layer formed with color ink. If this relationship is not taken into consideration, the white background may be formed with a width smaller than the minimum white width. However, prior art has not considered this point, and has not been able to solve the problem of image quality degradation.

[0016] On the other hand, in this embodiment, when the width of the second layer is equal to or less than a predetermined value, the width of the first layer is set to the same width as the second layer, thereby ensuring a minimum white width and preventing thin lines and characters from being missing. Also, when the width of the second layer is greater than the predetermined value, the width of the first layer is set to be smaller than the width of the second layer, thereby preventing the white base from spilling over the upper layer.

[0017] Furthermore, in this embodiment, when forming a white background (also referred to as a lower layer or a first layer), the minimum required white width (also referred to as a lower limit white width or a minimum white width) is ensured, thereby preventing thin lines and small characters formed with color inks from being missing. Furthermore, the lower limit white width (minimum white width) is calculated using the relationship between the color of the recording medium and the color of the layer (also referred to as an upper layer or a second layer) formed with color inks, preventing the lower layer from being formed with a width smaller than the lower limit white width. Therefore, according to this embodiment, the white background is reduced so as not to fall below the lower limit white width, preventing the white background from extending beyond the upper layer and preventing thin lines and characters from being missing.

[0018] Hereinafter, the lower limit width of white will be referred to as the minimum width of white. In addition, taking into consideration the following explanation, the white lower limit width means the minimum value when reducing (reducing, cutting) the white background. Also, since the white lower limit width also means the minimum width required when forming the white background, it is referred to as the white minimum width in the following explanation. Furthermore, in this embodiment, the predetermined value compared with the width of the second layer corresponds to the white lower limit width (minimum white width).

[0019] FIG. 1 shows a flowchart for explaining the image forming method of this embodiment. In S101, color information of the recording medium is acquired. S101 is a step corresponding to a first color information acquisition step, and in the first color information acquisition step, color information of the recording medium is acquired as first color information.

[0020] The method for acquiring the first color information can be selected as appropriate. For example, color information designated by a user may be used as the first color information. Here, "designated" may refer to, for example, inputting information using an input unit provided in the image forming apparatus, or transmitting information from another device to the image forming apparatus.

[0021] In addition to the above, the method of acquiring the first color information may also be to use a reading means such as a sensor provided in the image forming device, or to read the recording medium using the reading means and use the read color information as the first color information.

[0022] In S102, color information of lines, characters, etc. is acquired. S102 is a step corresponding to a second color information acquisition step, and in the second color information acquisition step, color information of a second layer is acquired as second color information from image information (also referred to as image data, etc.).

[0023] The content of the first color information and the content of the second color information can be selected appropriately, and examples thereof include brightness, saturation, and the like.

[0024] In S103, the minimum width of white is calculated. S103 is a step corresponding to the minimum width calculation step, in which the minimum width of white is calculated using the first color information and the second color information. As will be described in detail later, the minimum width of white can be calculated, for example, by finding the difference between the first color information and the second color information (also referred to as the color difference) and using the found color difference. Examples of the color difference include the difference in brightness and the difference in saturation.

[0025] The minimum width of the white portion can be selected as appropriate. For example, when the scanning direction of a liquid ejection head (also referred to as an inkjet head or ink ejection head) is defined as the main scanning direction and the direction perpendicular to the main scanning direction is defined as the sub-scanning direction, the minimum width of the white portion can be the length in the main scanning direction or the sub-scanning direction.

[0026] The lower limit white width (minimum white width) is the minimum width of the white background required to ensure that lines, characters, etc. formed on the white background are not missing. Since the minimum white width differs depending on the relationship between the color information of the recording medium and the color information of the lines, characters, etc., it is preferable to take into account the relationship between the color information of the recording medium and the color information of the lines, characters, etc., as in the minimum width calculation process described above.

[0027] If the relationship between the color information of the recording medium and the color information of lines, characters, etc. is not taken into consideration, when performing the process of reducing the white background area, the white background area may be reduced too much, resulting in problems such as missing lines, characters, etc.

[0028] S101 to S103, i.e., the first color information acquisition process, the second color information acquisition process, and the minimum width calculation process, are optional processes and may not be performed. For example, these processes can be omitted if the minimum white width is preset in advance. For example, if monochrome printing is assumed to be performed on a black T-shirt, the minimum white width can be determined by using a preset value without acquiring color information. Therefore, the specified white lower limit width (minimum white width) may be a preset value, or may be a value determined in the minimum width calculation process.

[0029] In S104, the amount of scraping is acquired. S104 is a step corresponding to the correction value acquisition step, and the correction value acquisition step acquires a correction value (amount of scraping) for reducing the width (1) of white to be ejected. The step of obtaining the width (1) of white to be ejected will be described later.

[0030] In this embodiment, when forming a layer of white ink as a base, a process is performed to reduce the width (1) of white ink to be ejected in order to prevent the white of the base from being visible due to misalignment of the color ink ejection positions. Since the process of reducing the width of white ink to be ejected also means reducing (reducing) the width of white ink to be ejected and the area formed by white ink, the correction value for reducing the width (1) of white ink to be ejected is also referred to as the reduction amount. Hereinafter, such a correction value will mainly be referred to as the reduction amount.

[0031] The amount of shaving can be changed as needed, but can be specified by the user, for example. The smaller the amount of shaving, the easier it is to prevent the color ink ejection position from shifting and the white background from showing through, but if a minimum area is not secured, lines and characters may be missing. Note that the term "user" does not necessarily refer to the user of the image forming apparatus, but can also include managers, designers, etc.

[0032] The process for acquiring the amount of cutting can be selected as appropriate, and for example, when a value input by a user is stored in an arbitrary memory unit (which may also be called a storage unit, a saving unit, etc.), the value may be extracted. Note that the above "input" may also be called designation, transmission, etc., and may be via another device.

[0033] In S105, the width (1) of the white to be discharged is calculated. S105 is a step corresponding to the planned formation area calculation step, in which the area of ​​the second layer to be formed is calculated from the image information (image data), and the area of ​​the first layer corresponding to the area of ​​the second layer to be formed is calculated to calculate the width (1) of the white to be discharged.

[0034] The area of ​​the second layer to be formed may include, for example, lines, letters, symbols, and figures.

[0035] The second layer to be formed is a layer formed with color ink, and may be one color or multiple colors. The width (1) of the white to be ejected may be the same or different depending on the position of the second layer.

[0036] When the scanning direction of the liquid ejection head is the main scanning direction and the direction perpendicular to the main scanning direction is the sub-scanning direction, for example, the minimum width of the white is the length in the main scanning direction or the sub-scanning direction, and the width (1) of the white to be ejected is the length in the same direction as the minimum width of the white.

[0037] In this example, the width (1) of the white to be ejected, the amount of scraping, and the direction of the minimum white width are all the same. For example, all lengths are set along the main scanning direction, or along the sub-scanning direction. By setting them in the same direction, these can be compared, and it is possible to determine whether to reduce the background area.

[0038] 1, the steps are described in the order of S101 to S105, but the order in which these steps are performed is not limited to the above example and can be changed as appropriate, except that S103 is performed after S101 and S102.

[0039] Next, an example of the determination process will be described. The determination process is a process for determining the ejection width of white to be ejected in the ejection process using the white width (1) to be ejected, the minimum white width, and a correction value (amount of scraping). In this embodiment, the determination process determines the ejection width of white by determining whether the white width (1) to be ejected is larger than the minimum white width.

[0040] In S106, it is determined whether the width (1) of white to be ejected is greater than the minimum width of white. The reason for this determination is to determine whether it is possible to perform processing to reduce the white area that serves as the background relative to the width (1) of white to be ejected. As described above, the width (1) of the white to be ejected is determined from the area of ​​the first layer corresponding to the area of ​​the second layer to be formed. Therefore, the determination in S106 is equivalent to comparing the width of the second layer with the minimum white width and determining whether the width of the second layer is greater than the minimum white width.

[0041] First, the process when the determination result in S106 is No, that is, when the white width (1) to be ejected is equal to or smaller than the minimum white width, will be described. If the white width (1) to be ejected is equal to or smaller than the minimum white width, the white width (1) to be ejected is set as the white ejection width, as shown in S107. S107 is a process for determining the ejection width of the white ink to be ejected in the ejection process. The white ejection width is the ejection width of the white ink determined in the determination process, and is also referred to as the white ejection width (after determination).

[0042] The process of S107 corresponds to the case where the width of the first layer to be ejected is equal to or less than a predetermined value. In this case, it can be said that the width of the first layer is made the same as the width of the second layer. Making the width of the first layer the same as the width of the second layer means that the width (1) of the white to be ejected is not cut (reduced). The width of the second layer is determined based on the area of ​​the second layer to be formed.

[0043] After the white ink ejection width is determined in the determination step, the ejection step is performed. In the ejection step, the inkjet head ejects white ink based on the white ink ejection width (S112), and ejects color inks onto the white background (S113). The first layer may be made of white ink and may consist of multiple layers, and the second layer may be made of color ink and may consist of multiple layers.

[0044] Next, the process when the result of the determination in S106 is Yes, that is, when the width (1) of the white to be ejected is greater than the minimum white width, will be described. When the result of the determination in S106 is Yes, the width (1) of the white to be ejected minus the amount of cutting is calculated as shown in S108. The value obtained by subtracting the width (1) of the white to be ejected by the amount of cutting is also referred to as the width (2) of the white to be ejected.

[0045] If the result of the determination in S106 is Yes, this corresponds to a case where the width of the first layer to be ejected is greater than the predetermined value, and the width of the first layer is made smaller than the width of the second layer. Therefore, the value of the white width (1) to be ejected is reduced and set as the white ejection width (after determination). This makes it possible to prevent the white background from spilling out of the upper layer. However, in this embodiment, it is preferable to obtain the white width (2) to be ejected and further compare it with the minimum white width. This makes it possible to prevent the white background area from being reduced too much, and further prevents lines, characters, etc. from being missing.

[0046] Next, as shown in S109, it is determined whether the width (2) of white to be ejected is equal to or less than the minimum width of white. The reason for this determination is to determine whether the width of white is smaller than the minimum necessary width when the white background is reduced by the amount of scraping.

[0047] First, the process when the determination result in S109 is Yes, that is, when the white width (2) to be ejected is equal to or less than the minimum white width, will be described. If the white width (2) to be ejected is equal to or less than the minimum white width, the minimum white width is set as the white ejection width (after determination), as shown in S110. This ensures the minimum necessary white width even if an attempt is made to reduce the white background beyond the minimum necessary, thereby preventing defects such as missing lines or characters.

[0048] Next, we will explain the processing when the judgment result of S109 is No, that is, when the white width (2) to be discharged is larger than the minimum white width. If the white width (2) to be discharged is larger than the minimum white width, as shown in S111, the white width (2) to be discharged is set as the white discharge width (after determination). This makes it possible to reduce the white background by, for example, the amount of scraping specified by the user.

[0049] After S110 and S111, i.e., after the white ejection width is determined in the determination step, the ejection step is performed. In the ejection step, the inkjet head ejects white ink based on the white ejection width (S112), and ejects color inks onto the white background (S113).

[0050] In this embodiment, whether or not to use an equal sign (=) when making the determinations in S106 and S109 can be changed as appropriate. For example, in the determination in S106, it may be determined whether the width (1) of the white to be ejected is equal to or greater than the minimum white width. Also, in the determination in S109, it may be determined whether the width (2) of the white to be ejected is smaller than the minimum white width.

[0051] As described above, the determination step determines the white discharge width by determining whether the white width (1) to be discharged is greater than the minimum white width. For example, as in S107, if the white width (1) to be discharged is equal to or less than the minimum white width, the determination step determines the white discharge width to be the white width (1).

[0052] Also, in the determination process, for example, in S106 and S108 to S110, if the white width (1) to be ejected is larger than the minimum white width (lower limit white width), the area of ​​the first layer to be formed is subtracted by the amount of scraping to determine the white width (2) to be ejected, and if the white width (2) to be ejected is equal to or smaller than the minimum white width, the minimum white width is set as the white ejection width.

[0053] Also, in the determination process, for example, in S106, S108, S109, and S111, if the white width (1) to be ejected is larger than the minimum white width (lower limit white width), the area of ​​the first layer to be formed is subtracted by the scraping amount to obtain the white width (2) to be ejected, and if the white width (2) to be ejected is larger than the minimum white width, the white width (2) to be ejected is set as the white ejection width.

[0054] Next, a specific example of printing lines with color inks on a base formed by ejecting white ink will be described with reference to Table 1 and FIG.

[0055] Table 1 below shows three examples: an example of printing a line with a width of 0.5 mm (Example 1), an example of printing a line with a width of 3.0 mm (Example 2), and an example of printing a line with a width of 5.0 mm (Example 3). These values ​​are listed in the "Line Width" column in the table.

[0056] [Table 1]

[0057] The table includes a column for "Width of white ink to be ejected (1)." The value in this column is the same as the value for the line width, meaning that the white area that will serve as the base and the area of ​​the color ink layer formed on top of the base will be ejected so as to be the same size.

[0058] In this example, when forming the white base (first layer), a process is performed to reduce the width (1) of the white to be ejected. As mentioned above, this is to prevent the ejection position of the color ink from shifting and the white of the base from becoming visible. In this example, the numerical value by which the width of the white base is reduced is listed in the table as "Width by which the white area is reduced (amount of reduction)."

[0059] The white width after the process of reducing the white width (1) to be ejected is set as "white width (2) to be ejected" as shown in the table. The white width (2) to be ejected is Planned white width (2) = Planned white width (1) - scraping amount In addition, since the width of the line and the width of the white to be ejected (1) are the same value, Width of white to be ejected (2) = Line width - Scraping amount It may also be possible to use the following.

[0060] As will be described later, in Example 1, the line width is smaller than the minimum white width, so the width of the white to be ejected cannot be reduced using the scraping amount. For this reason, in Example 1, there is no need to calculate the white width (2) to be ejected, and this is indicated by "-" in Table 1. However, the white width (2) to be ejected may also be calculated without using "-".

[0061] The minimum white width of the background is listed in the table as a numerical value. The minimum white width is determined using color information of the recording medium and color information of the layer formed by the color ink. An example of how to determine the minimum white width will be described later.

[0062] In this example, the line width is calculated from the image information (image data), and the corresponding background is set as the white width (1) (before conversion).Then, the white width (2) to be discharged is calculated using the scraping amount obtained in advance, and the white discharge width is determined using the separately calculated minimum white width.

[0063] Examples 1 to 3 in Table 1 will be explained below with reference to Fig. 2. The explanation will also refer to the flowchart in Fig. 1.

[0064] FIG. 2A is a schematic diagram for explaining Example 1. The left side of FIG. 2A shows the lines formed by the white background and color inks to be ejected before the determination process, and the right side of FIG. 2A shows the lines formed by the white background and color inks after the determination process. In the figure, the lines formed by the color inks are based on image information (image data), and the lines formed by the color inks do not change before or after the determination process. Note that the period before the determination process will also be simply referred to as "before determination," and the period after the determination process will also be simply referred to as "after determination."

[0065] The left side of the figure (before determination) shows a schematic representation of the white area to be ejected, and the width of the white background to be ejected corresponds to the white width (1) to be ejected. As described above, the white width (1) to be ejected is the same width as the line formed by the color ink (hereinafter sometimes simply referred to as the line). The target of the determination process is the white background, and determination is made so that the white width to be ejected is small. However, as will be explained below, in Example 1 the white width to be ejected is not changed (the width is not reduced), so the left and right sides (before and after determination) are the same size.

[0066] As shown in the table, in Example 1, the width of the line formed by the color ink is 0.5 mm, and the minimum white width is 1.5 mm. When the planned white width (1) is compared with the minimum white width, the planned white width (1) is less than or equal to the minimum white width, so white ink is ejected at the planned white width (1). In other words, the planned white width (1) is set as the white ejection width (after determination).

[0067] The above determination corresponds to the determination in S106 in the flowchart of Figure 1, and since the determination is No in Example 1, as shown in S107, the width (1) of white to be ejected is set as the ejection width of white. Note that, as mentioned above, the width (1) of white to be ejected is set to the same width as the line formed by color ink, so the width of the line and the minimum width of white may be compared in size. In this case, the same result is obtained.

[0068] Next, the inkjet head ejects white ink based on the determined white ejection width (S112), and ejects color ink onto the white background (S113). In Example 1, the inkjet head ejects white ink with a width of 0.5 mm, and then ejects color ink with a width of 0.5 mm onto the background of the ejected white ink.

[0069] In this way, in Example 1, because the line width is thin, that is, because the area formed by white ink is smaller than the minimum white width, the width of the white background is not reduced. This prevents the width of the white background from becoming smaller than the minimum required width in the case of thin lines, and prevents problems such as missing lines.

[0070] Figure 2B is a schematic diagram for explaining Example 2, and similarly to Figure 2A, shows on the left side the lines formed by the white background and color inks to be ejected before the decision, and on the right side the lines formed by the white background and color inks after the decision.

[0071] In Example 2, the line width is 3.0 mm, so the white width (1) to be ejected is 3.0 mm (Table 1, left side of Figure 2B). The minimum white width is 1.5 mm, just like in Example 1. Therefore, when comparing the white width (1) to be ejected and the minimum white width, the white width (1) to be ejected is greater than the minimum white width. Therefore, in Example 2, the determination in S106 is Yes, and the white width (1) to be ejected can be reduced, so the white width (1) to be ejected minus the amount of scraping, i.e., the white width (2) to be ejected, is calculated (S108). In Example 2, the white width (2) to be ejected is calculated as 1.0 mm (3.0 mm - 2.0 mm).

[0072] Next, the white width (2) to be ejected is compared with the minimum white width (S109). In Example 2, the white width (2) to be ejected is equal to or less than the minimum white width, so if the white background is formed with the white width (2) to be ejected, it will be smaller than the minimum white width. Therefore, if an attempt is made to eject the white at a width smaller than the minimum white width, the line will be missing, so the minimum white width is set as the white ejection width (after determination) (S110).

[0073] Thus, in Example 2, as shown on the right side of Figure 2B, the white ejection width (after determination) is 1.5 mm (minimum white width). As for the subsequent processing, similar to Example 1, the inkjet head ejects white ink based on the white ejection width (after determination) (S112), and ejects color inks onto the white background (S113). In this way, in Example 2, when reducing the white background area, it is possible to ensure the minimum white width to prevent missing lines.

[0074] Figure 2C is a schematic diagram for explaining Example 3, and similarly to Figure 2A, the left side shows the white background and the lines formed by the color inks to be ejected before the decision, and the right side shows the lines formed by the white background and the color inks after the decision.

[0075] In Example 3, the line width is 5.0 mm, so the white width (1) to be ejected is 5.0 mm (Table 1, left side of Figure 2C). The minimum white width is 1.5 mm, just like in Example 1. Therefore, when comparing the line width and the minimum white width, the white width (1) to be ejected is greater than the minimum white width, just like in Example 2. Therefore, in Example 3, just like in Example 2, the determination in S106 is Yes, and the white width to be ejected can be reduced, so the white width (1) to be ejected minus the amount of scraping, i.e., the white width (2) to be ejected, is calculated (S108). In Example 2, the white width (2) to be ejected is calculated to be 3.0 mm (5.0 mm - 2.0 mm).

[0076] Next, the white width (2) to be ejected is compared with the minimum white width (S109). In Example 3, the white width (2) to be ejected is greater than the minimum white width, so the minimum white width is secured even if the white background is set as the white width (2) to be ejected. Therefore, the white width (2) to be ejected is set as the white ejection width (after determination) (S111).

[0077] Thus, in Example 3, as shown on the right side of FIG. 2C, the white ejection width (after determination) is 3.0 mm (the white width (2) to be ejected). As in Example 1, the subsequent process involves the inkjet head ejecting white ink based on the white ejection width (after determination) (S112), and ejecting color ink onto the white background (S113). In this way, in Example 3, when reducing the white background area, the white background area can be reduced by the specified amount of scraping while ensuring the minimum white width.

[0078] Next, an example of determining the minimum white width from the color information of the recording medium and the color information of the upper layer (second layer) will be described. In this embodiment, when determining the minimum white width using the color information of the recording medium and the color information of the upper layer, it is preferable to determine the minimum white width using the difference between the color information of the recording medium and the color information of the upper layer.

[0079] FIG. 3 is a diagram for explaining an example of how to obtain the minimum white width. In the example shown in the figure, the vertical axis represents the minimum white width [mm], and the horizontal axis represents the brightness difference between the recording medium and the upper layer. As shown in the figure, in this example, the greater the brightness difference, the greater the minimum white width.

[0080] In the above example, the minimum width of white is determined from the difference in brightness between the recording medium and the upper layer, but this is not limited to this in the present embodiment, and the minimum width of white may be determined from the difference in saturation, for example. The difference in saturation between the recording medium and the upper layer can also be in a proportional relationship, just like the difference in brightness.

[0081] As described above, the minimum width of white can be easily determined by using the difference in brightness and saturation.

[0082] In this embodiment, the recording medium can be selected as appropriate, but among them, cloth is particularly suitable.

[0083] Next, a specific example of printing characters will be described with reference to FIGS. FIG. 4(A) is a diagram showing a schematic diagram of image information (image data) when forming characters 20 on a recording medium 10. The image information is scanned to detect line and character areas, and the area of ​​the characters (second layer) to be formed with color ink is identified. In the example shown here, a shirt is assumed as the recording medium 10. The recording medium 10 is shown with a dashed line to illustrate that scanning is performed on the data.

[0084] In Figure 4(A), the main scanning direction represents the scanning direction of the inkjet head, and the sub-scanning direction is the direction perpendicular to the main scanning direction. This example shows scanning in the direction along the main scanning direction, and the scanning direction is indicated by the black arrow in the figure. As shown in the figure, scanning is performed from the left side of the paper to the right side of the paper. The scanning order is in the direction along the sub-scanning direction, as indicated by the white arrow in the figure. The upper side of the paper is the upstream side of the scanning order, and the lower side of the paper is the downstream side of the scanning order. By scanning the image information in this way, the area of ​​character 20 is detected.

[0085] Although the scanning order is used in this example for the sake of explanation, this embodiment is not limited to a sequential scanning method. The area of ​​the character 20 may be detected in one scan. Furthermore, the term "detection" may also be referred to as "recognition," "understanding," or "detection."

[0086] Figure 4(B) is a schematic diagram of an enlarged version of character 20 in Figure 4(A), showing several scans as examples. Here, three scans a to c are shown as scan examples, but they are shown for illustrative purposes only. It is assumed that there are other scans between scan a and scan b, and between scan b and scan c, and that the scans are performed without any gaps.

[0087] Figure 5(A) is a diagram for explaining the areas recognized as character areas in the example scan of Figure 4(B). In scan a, a-1 is recognized as a character area, in scan b, b-1 to b-4 are recognized as character areas, and in scan c, c-1 to c-3 are recognized as character areas. These a-1 to c-3 are areas of the second layer to be formed, and their widths (lengths) in the main scanning direction correspond to the widths of lines such as Table 1, and correspond to the width (1) of the white to be ejected.

[0088] In the illustrated example, a-1 to c-3 are shown as areas that are angled with respect to the sub-scanning direction, but this is for the sake of explanation. If the scanning width (width in the sub-scanning direction) is made small, characters can be considered as a collection of lines.

[0089] In the figure, the minimum white width is also shown, and in this example, the minimum white width is the length in the main scanning direction. The lower limit white width and the white width (1) to be ejected are lengths in the same direction, and the main scanning direction lengths of these a-1 to c-3 are compared with the minimum white width.

[0090] FIG. 5B is a schematic diagram illustrating the comparison of the white width (1) to be ejected and the minimum white width. Here, a-1 and b-2 are shown as examples. Comparing the length of a-1 in the main scanning direction (the white width (1) to be ejected) and the minimum white width reveals that the length of a-1 in the main scanning direction is greater. Therefore, the white width (2) to be ejected is calculated, and the white ejection width is then calculated (S106: Yes). On the other hand, comparing the length of b-2 in the main scanning direction and the minimum white width reveals that the length of b-2 in the main scanning direction is smaller than the minimum white width. Therefore, the white width (1) to be ejected cannot be reduced. Therefore, white ink is ejected to the length of b-2 in the main scanning direction (the white width (1) to be ejected) (S106: No). Similar comparisons are also performed on areas other than a-1 and b-2 to calculate the white ejection width.

[0091] In the above example, the areas of the first layer (base) corresponding to the second layer (characters) to be formed are detected as a-1 to c-3. Because these areas are areas onto which color inks are to be ejected, these areas may also be referred to as "areas sandwiched between areas onto which color inks are not to be ejected." The recognized line or character areas may also be referred to as areas sandwiched between areas onto which color inks are not to be ejected. In this way, the width (1) of the white to be ejected in the process of calculating the area to be formed is the length of the area sandwiched between areas onto which the second layer is not to be formed in the main scanning direction or the sub-scanning direction.

[0092] FIG. 6A is a diagram similar to FIG. 4A, illustrating another example different from the above example. While FIG. 4A illustrates an example of scanning along the main scanning direction, this example illustrates an example of scanning along the sub-scanning direction. That is, as illustrated, scanning is performed from the top of the page to the bottom of the page. The scanning order is in the main scanning direction, with the left side of the page being the upstream side of the scanning order and the right side of the page being the downstream side of the scanning order. In this example, the area of ​​character 20 is also detected by scanning image information in this manner.

[0093] Fig. 6(B) is a diagram similar to Fig. 4(B), and is a schematic diagram of an enlarged version of the character 20 in Fig. 6(A). In the diagram, several scans are shown as examples, and three scans p to r are shown here as examples of scans.

[0094] Figure 7 is a diagram similar to Figure 5(A) and explains the areas recognized as character areas in the example scan of Figure 6(B). In scan p, p-1 to p-3 are recognized as character areas, in scan q, q-1 to q-3 are recognized as character areas, and in scan r, c-1 is recognized as a character area. These p-1 to r-1 are areas of the second layer to be formed, and their widths (lengths) in the main scanning direction correspond to the widths of lines such as Table 1, and correspond to the width (1) of the white to be ejected.

[0095] In the figure, the minimum white width is also shown, and in this example, the minimum white width is the length in the sub-scanning direction. The lengths of p-1 to r-1 in the sub-scanning direction are compared with the minimum white width. Since this is the same as the example shown in Figure 5, it is not shown here. For example, in p-1, the white width (1) to be ejected is smaller than the minimum white width, so the process of S106 No is performed. On the other hand, for example, in r-1, the white width (1) to be ejected is larger than the minimum white width, so the process of S106 Yes is performed.

[0096] As explained above, the direction of the white width (1) to be ejected and the minimum white width can be, for example, the main scanning direction or the sub-scanning direction, and can be selected as appropriate. It is also possible to use both the main scanning direction and the sub-scanning direction. For example, at the top of the character "a" (the area indicated by the dashed line in Figure 7), the white of the background may protrude into the sub-scanning direction because the white is scraped in the main scanning direction but not in the sub-scanning direction. In this case, using both the main scanning direction and the sub-scanning direction can further prevent the white of the background from protruding. While not particularly limited, the direction of the white width (1) to be ejected and the minimum white width can be selected as appropriate depending on the character, the shape of the line, the type of fabric, etc.

[0097] (Image forming device) Next, an embodiment of the image forming apparatus of the present invention will be described. FIG. 8 is a perspective view illustrating an example of the configuration of an image applying system 1000 having the image forming apparatus 1 of this embodiment. The image application system 1000 includes a cassette 200, an image forming device 1, and a heating device 500. The cassette 200 is a member for holding the portion of the fabric 400 on which an image is to be formed in a flat state, and is shared by both the image forming device 1 and the heating device 500.

[0098] The image forming device 1 has a detachable cassette 200 as an example of a holding unit, and forms an image on fabric 400 held in the cassette 200. The heating device 500 also has a detachable cassette 200, and heats the fabric 400 on which the image has been formed together with the cassette 200, thereby fixing the image to the fabric 400.

[0099] Although the image forming apparatus 1 is shown placed on the heating apparatus 500, the image forming apparatus 1 and the heating apparatus 500 are separate entities and can be placed side by side or spaced apart. The heating apparatus 500 may be provided as needed.

[0100] When applying an image to fabric 400 using this image application system 1000, as shown in FIG. 8, a cassette 200 holding fabric 400 is attached to a stage 111 of an image forming apparatus 1, and an image is formed by the image forming apparatus 1.

[0101] After the image formation is completed, the front door 502 of the heating device 500 is opened, the cassette 200 still holding the fabric 400 is removed from the image forming apparatus 1, and the cassette 200 is then loaded directly into the heating device 500. By heating the fabric 400 together with the cassette 200 by the heating device 500, the image formed on the fabric 400 is easily fixed to the fabric 400.

[0102] It should be noted that various information can be received from the user through the operation panel shown in Fig. 8. For example, a correction value (amount of scraping) or color information of the recording medium can be received from the user.

[0103] Next, the configuration of the image forming apparatus 1 will be described with reference to FIGS. Figure 9 is an oblique view illustrating an example of the configuration of the image forming apparatus 1, Figure 10 is an oblique view illustrating an example of the configuration of the image forming apparatus 1 seen from a direction different from that of Figure 9, and Figure 11 is a diagram illustrating an example of the configuration of a carriage 121 provided in the image forming apparatus 1.

[0104] The image forming device 1 includes, within the device body 100, a stage 111 that removably holds a cassette 200 that holds fabric 400 and moves back and forth, and an image forming section 112 that forms an image on the fabric 400 held in the cassette 200.

[0105] Here, examples of fabric 400 (recording medium) include items formed from a single piece of fabric such as a handkerchief or towel, items processed into clothing such as a T-shirt or sweatshirt, and items that are part of a product such as a tote bag.

[0106] The fabric is not particularly limited and includes fabrics of different weaves and materials. Fabrics are not limited to woven fabrics, but also include knitted fabrics, lace (knitted fabrics), felt, and nonwoven fabrics. Both natural and synthetic materials can be used, including silk, linen, kudzu, and cotton.

[0107] Furthermore, the recording medium is not limited to fabric, and other recording media can also be used for printing with white ink and color ink. For example, plastic films such as vinyl chloride resin film, polyethylene terephthalate (PET) film, polypropylene, polyethylene, and polycarbonate film can be used. Furthermore, by adjusting the configuration of the path for transporting the recording medium, ceramics, glass, metal, and the like can also be used.

[0108] The stage 111 is provided on a transport structure 113 that is held so as to be reciprocable in the direction of arrow Y (sub-scanning direction) relative to the apparatus main body 100. Specifically, the stage 111 is connected to the transport structure 113, and a slider portion 116 of the transport structure 113 is held so as to be movable by a transport guide member 115 that is arranged along the direction of arrow Y on a bottom housing portion 114 of the apparatus main body 100. The stage 111 (transport structure 113) is reciprocated in the direction of arrow Y by a sub-scanning motor M2.

[0109] The image forming unit 112 includes a carriage 121 that moves in the direction of the arrow X (main scanning direction) relative to the stage 111. The carriage 121, which is an example of a movable unit, is movably held by a guide member 123 arranged along the direction of the arrow X, and is reciprocated in the direction of the arrow X by a main scanning motor M1 via a scanning mechanism unit such as a timing belt 125. The carriage 121 is also equipped with an ink ejection head 122 that serves as a liquid ejection head that ejects ink onto the surface of the fabric to form an image.

[0110] 11, a plurality of ink ejection heads 122 (122c, 122m, 122y, 122k, 122w1, 122w2) are mounted on the carriage 121. Each of the ink ejection heads 122 has a large number of nozzles (ejection ports) for ejecting ink, and is arranged in the direction of arrow X relative to the stage 111.

[0111] The ink ejection head 122c ejects cyan ink, and the ink ejection head 122m ejects magenta ink. The ink ejection head 122y ejects yellow ink, and the ink ejection head 122k ejects black ink. The ink ejection head 122w1 and the ink ejection head 122w2 both eject white ink. When there is no need to distinguish between the ink ejection head 122w1 and the ink ejection head 122w2, they are collectively referred to as the ink ejection head 122w.

[0112] Ink of each color is supplied to each ink ejection head 122 from a tank mounted for each color on the carriage 121. Note that the color and number of inks may be arbitrary and can be changed as necessary.

[0113] 9 and 10, in the image forming apparatus 1, the fabric 400 is set on the platen member 300 of the cassette 200, and the cassette 200 is then attached to and held on the stage 111 inside the apparatus main body 100. Then, the stage 111 is repeatedly moved in the direction of arrow Y and the ink ejection head 122 is repeatedly moved back and forth in the direction of arrow X to form a desired image on the fabric 400. Here, the platen member 300 is an example of a mounting member.

[0114] In this case, the stage 111 can be raised and lowered in the direction of arrow Z by a stage lifting motor M3, and the gap between the fabric 400 and the ink ejection head 122 can be adjusted to a predetermined gap by raising and lowering the stage 111 according to the thickness of the fabric 400. Note that the image forming unit 112 including the carriage 121 may also be configured to be able to be raised and lowered.

[0115] Next, the hardware configuration of the control unit 700 of the image forming apparatus 1 will be described with reference to Fig. 12. Fig. 12 is a block diagram illustrating an example of the hardware configuration of the control unit 700.

[0116] The control unit 700 controls the width of the first layer to be ejected to be the same as the width of the second layer when the width of the first layer to be ejected is equal to or smaller than a predetermined value, and controls the width of the first layer to be smaller than the width of the second layer when the width of the first layer to be ejected is larger than the predetermined value.

[0117] Furthermore, the control unit 700 performs, for example, a process of calculating a planned formation area, a process of acquiring a correction value, and a process of determining, and may also perform a process of acquiring first color information, a process of acquiring second color information, and a process of calculating a minimum width, and further performs various other controls as necessary.Whether the control unit 700 performs the first color information acquisition process can be selected as appropriate, and if the control unit 700 does not perform the first color information acquisition process, it is preferable that the device includes a reading means that performs the first color information acquisition process.

[0118] As shown in FIG. 12, the control unit 700 includes a CPU (Central Processing Unit) 701, a ROM (Read Only Memory) 702, a RAM (Random Access Memory) 703, an NVRAM (Non-Volatile RAM) 704, and an ASIC (Application Specific Integrated Circuit) 705.

[0119] The CPU 701 comprehensively controls the entire image forming apparatus 1. The ROM 702 is a memory that stores programs executed by the CPU 701 and other fixed data. The RAM 703 is a memory that temporarily stores image data, print data, etc. Here, the CPU 701, ROM 702, and RAM 703 correspond to a main control unit 700A (computer) of the image forming apparatus 1.

[0120] The NVRAM 704 is a non-volatile memory that can retain data even when power is cut off to the image forming apparatus 1. The ASIC 705 processes various types of signal processing, image processing such as sorting, and other input / output signals for controlling the entire image forming apparatus 1.

[0121] The control unit 700 also includes a host I / F (Interface) 706, an I / O (Input / Output) 707, a head drive control unit 708, a main scanning motor drive unit 709, a sub-scanning motor drive unit 710, and an elevation motor drive unit 711.

[0122] The host I / F 706 transmits and receives data and signals to and from the host H. The head drive control unit 708 generates a drive waveform for controlling the drive of the ink ejection head 122.

[0123] A main scanning motor drive unit 709 drives a main scanning motor M1, which moves the carriage 121 in the X direction. A sub-scanning motor drive unit 710 drives a sub-scanning motor M2, which moves the stage 111 in the Y direction. A lift motor drive unit 711 drives a stage lift motor M3 and an image forming unit lift motor M4. The stage lift motor M3 moves the stage 111 up and down in the Z direction, and the image forming unit lift motor M4 moves the image forming unit 112 up and down in the Z direction.

[0124] The I / O 707 acquires information from a sensor 713 provided in the image forming apparatus 1 and extracts information necessary for controlling each part of the image forming apparatus 1. An operation panel 712 for inputting and displaying various pieces of information is also connected to the control unit 700. As the sensor 713, for example, a reading means for reading color information of a recording medium can be used.

[0125] The control unit 700 receives image data from a host H, such as an information processing device such as a PC (Personal Computer), an image reading device such as an image scanner, or an imaging device such as a digital camera, via a cable or a network through a host I / F 706. The CPU 701 and ASIC 705 analyze the image data received by the host I / F 706 and generate print data.

[0126] The present invention also provides a printed matter having a recording medium, a first layer of white ink, and a second layer of color ink on the first layer. The printed matter obtained by the present invention relates to a printed matter in which the width of the first layer is the same as the width of the second layer when the width of the second layer is equal to or less than a predetermined value, and the width of the first layer is narrower than the width of the second layer when the width of the second layer is greater than the predetermined value. [Explanation of symbols]

[0127] 1. Image forming device 100 Device body Stage 111 112 Image forming unit 121 Carriage 122 Ink ejection head 200 cassettes 300 Platen member 400 fabric 500 Heating device 700 control section [Prior art documents] [Patent documents]

[0128] [Patent Document 1] Japanese Patent Application Publication No. 2015-222323

Claims

1. 1. An image forming method comprising: a discharge step of discharging white ink and color inks onto a recording medium using a liquid discharge head to form a first layer of the white ink, and forming a second layer of the color inks on the first layer, An image forming method characterized in that, when the width of the second layer is equal to or less than a predetermined value, the width of the first layer is made the same as the width of the second layer, and, when the width of the second layer is greater than the predetermined value, the width of the first layer is made smaller than the width of the second layer.

2. a process of calculating a region to be formed of the second layer from image information, and a region of the first layer corresponding to the region to be formed of the second layer, thereby calculating a width (1) of white to be ejected; a correction value acquisition step of acquiring a correction value for reducing the width (1) of the white ink to be ejected; a determination step of determining a discharge width of white to be discharged in the discharge step using the white width (1) to be discharged, the white lower limit width, and the correction value, when the predetermined value is a white lower limit width; and The lower limit width of the white and the width (1) of the white to be ejected are lengths in the same direction, The determining step determines a discharge width of the white by determining whether the white width (1) to be discharged is larger than a lower limit width of the white; 2. The image forming method according to claim 1, wherein the ejection step ejects the white ink based on the ejection width of the white ink determined in the determination step.

3. the liquid ejection head scans the recording medium, the scanning direction of the liquid ejection head being a main scanning direction, and the direction perpendicular to the main scanning direction being a sub-scanning direction; 3. The image forming method according to claim 2, wherein the lower limit width of the white and the width (1) of the white to be ejected are lengths in the main scanning direction or the sub-scanning direction.

4. 4. The image forming method according to claim 3, wherein the width (1) of the white to be ejected in the process of calculating the area to be formed is the length of an area sandwiched between areas in which the second layer is not formed in the main scanning direction or the sub-scanning direction.

5. a first color information acquisition step of acquiring color information of the recording medium as first color information; a second color information acquisition step of acquiring color information of the second layer from the image information as second color information; 5. The image forming method according to claim 2, further comprising: a minimum width calculation step of calculating a lower limit width of white using the first color information and the second color information.

6. The image forming method according to claim 5, characterized in that the first color information acquisition process uses color information specified by a user as the first color information, or reads the recording medium using a reading means and uses the read color information as the first color information.

7. 7. The image forming method according to claim 5, wherein the minimum width calculation step uses a difference between the brightness in the first color information and the brightness in the second color information.

8. 7. The image forming method according to claim 5, wherein the minimum width calculation step calculates the minimum width using a difference between the saturation in the first color information and the saturation in the second color information.

9. The image forming method according to any one of claims 2 to 8, characterized in that, in the determination step, when the white width (1) to be ejected is equal to or smaller than the white lower limit width, the white width (1) to be ejected is set as the white ejection width.

10. The image forming method according to any one of claims 2 to 8, characterized in that in the determination step, when the white width (1) to be ejected is larger than the white lower limit width, the white width (2) to be ejected is determined by subtracting the white width (1) to be ejected by the correction value, and when the white width (2) to be ejected is equal to or smaller than the white lower limit width, the white lower limit width is set as the white ejection width.

11. The image forming method according to any one of claims 2 to 8, characterized in that in the determination step, if the white width (1) to be ejected is larger than the white lower limit width, the white width (2) to be ejected is determined by subtracting the white width (1) to be ejected by the correction value, and if the white width (2) to be ejected is larger than the white lower limit width, the white width (2) to be ejected is set as the white ejection width.

12. 12. The image forming method according to claim 1, wherein the recording medium is a cloth.

13. An image forming apparatus for carrying out the image forming method according to any one of claims 2 to 11, An image forming apparatus comprising: the liquid ejection head; and a control unit that performs the planned formation region calculation step, the correction value acquisition step, and the determination step.

14. An image forming apparatus that forms a first layer of white ink and a second layer of color ink on the first layer on a recording medium, An image forming apparatus characterized in that, when the width of the second layer is equal to or less than a predetermined value, the width of the first layer is made the same as the width of the second layer, and, when the width of the second layer is greater than the predetermined value, the width of the first layer is made smaller than the width of the second layer.

Images