Printing system, printing device and printing method

Abstract

To provide a printing system that can suppress a color of a medium from changing hue of an image, while suppressing white ink from being used.SOLUTION: A printing system comprises a discharge part that discharges color ink and white ink to a medium, and a control part that controls the discharge part. The printing system obtains image data, information on colors of the medium and information on a density of white ink. The control part calculates a masking ratio of the medium on the basis of the information on colors of the medium and the density of the while ink, calculates adhesion amounts of white ink that are necessary for masking the medium on the basis of the calculated masking ratio, reads out an image parameter describe below in the image data, performs threshold determination of the read image parameter, and adjusts the adhesion amounts of white ink on the basis of the determined result. One or more image parameters are selected from adhesion amounts of color ink and color data that can be measured with a measurement instrument.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a printing system, a printing device, and a printing method. [Background technology]

[0002] A known example of a printing device is a DTF (Direct To Film) printer. DTF printers form an image to be transferred by applying color ink to a transfer substrate such as film. For example, adhesive powder is applied to the image to be transferred, and the color ink on the film is transferred to a transfer material such as clothing.

[0003] In such DTF printers and printers using other methods, a base is formed using white ink to ensure wash fastness and conceal the transfer material.

[0004] Patent Document 1 discloses a printing method that uses an appropriate amount of white ink according to the color of the image while maintaining good washing fastness, in order to reduce costs when forming an image on a medium. Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional techniques that reduce the amount of ink applied have the problem of image color variations depending on the color of the medium or transfer material. On the other hand, increasing the amount of white ink, etc., to prevent image color variations depending on the color of the medium or transfer material increases costs and can lead to problems such as insufficient drying. Insufficient drying can lead to ink bleeding and poor quality.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a printing system that can suppress changes in the color of an image depending on the color of the medium while reducing the amount of white ink used. [Means for solving the problem]

[0007] In order to solve the above problems, the printing system of the present invention comprises: A printing system having an ejection unit that ejects color inks and white ink onto a medium, and a control unit that controls the ejection unit, The printing system obtains image data, information about the color of the medium, and information about the density of the white ink; The control unit calculates a concealment rate of the medium based on information about the color of the medium and the density of the white ink, calculates the amount of white ink to be applied that is necessary to conceal the medium based on the calculated concealment rate, reads the following image parameters from the image data, performs threshold determination on the read image parameters, and adjusts the amount of white ink to be applied based on the determination result: It is characterized by: [Image parameters] The image parameters are one or more selected from the color ink deposition amount and color data measurable by a colorimeter. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a printing system that can suppress changes in the color of an image depending on the color of the medium while reducing the amount of white ink used. [Brief explanation of the drawings]

[0009] [Figure 1] 1A and 1B are diagrams illustrating an example of a printing system according to the present invention. [Figure 2] 10A and 10B are diagrams illustrating an example of control of the amount of white ink applied. [Figure 3A] 1 is a flow chart illustrating an example of processing performed by the printing system of the present invention, in which a threshold determination is made on the amount of color ink applied. [Figure 3B] 1 is a flow chart illustrating an example of processing performed by the printing system of the present invention, in which threshold value determination is performed on color data. [Figure 4]10A and 10B are diagrams for explaining another example of control of the amount of white ink adhesion. [Figure 5] 10 is a flow chart illustrating another example of the processing of the printing system of the present invention, in which a determination is made between the amount of color ink applied and a threshold value of color data. [Figure 6] 1A and 1B are diagrams illustrating ink flow. [Figure 7] FIG. 10 is a diagram illustrating an example of gradation processing. [Figure 8] 10 is a flowchart illustrating another example of the processing of the printing system of the present invention. [Figure 9] 10 is a flowchart illustrating another example of the processing of the printing system of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] The printing system, printing device, and printing method 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 aspect that achieves the functions and effects of the present invention is within the scope of the present invention.

[0011] (First embodiment) An embodiment of the present invention will be described below. In this embodiment, ink is ejected onto a medium.

[0012] The printing system of this embodiment is a printing system having an ejection unit that ejects color inks and white ink onto a medium, and a control unit that controls the ejection unit, wherein the printing system obtains image data, information about the color of the medium, and information about the density of the white ink, and the control unit calculates a concealment rate of the medium based on the information about the color of the medium and the density of the white ink, calculates the amount of white ink to be applied to conceal the medium based on the calculated concealment rate, and reads the following image parameters from the image data, performs threshold judgment on the read image parameters, and adjusts the amount of white ink to be applied based on the judgment result: [Image parameters] The image parameters are one or more selected from the color ink deposition amount and color data measurable by a colorimeter.

[0013] The printing device of this embodiment is a printing device having an ejection unit that ejects color inks and white ink onto a medium, and a control unit that controls the ejection unit, and the printing device obtains image data, information about the color of the medium, and information about the density of the white ink, and the control unit calculates the concealment rate of the medium based on the information about the color of the medium and the density of the white ink, calculates the amount of white ink to be applied to conceal the medium based on the calculated concealment rate, and reads the following image parameters from the image data, performs threshold judgment on the read image parameters, and adjusts the amount of white ink to be applied based on the judgment result: [Image parameters] The image parameters are one or more selected from the color ink deposition amount and color data measurable by a colorimeter.

[0014] The printing method of this embodiment is a printing method including an ejection step of ejecting color inks and white ink onto a medium using a printing device, and a control step of controlling the ejection of the color inks and white ink, wherein the printing method obtains image data, information about the color of the medium, and information about the density of the white ink, and the control step calculates a concealment rate of the medium based on the information about the color of the medium and the density of the white ink, calculates the amount of white ink applied that is necessary to conceal the medium based on the calculated concealment rate, reads the following image parameters from the image data, performs threshold judgment on the read image parameters, and adjusts the amount of white ink applied based on the judgment result: [Image parameters] The image parameters are one or more selected from the color ink deposition amount and color data measurable by a colorimeter.

[0015] In the following description, the terms medium, transfer medium, and transfer material have the same meaning.

[0016] In this embodiment, the concealment rate of the medium is calculated using information on the color of the medium and the density of the white ink, and the calculated concealment rate is used to calculate the amount of white ink to be applied to conceal the medium. Furthermore, image parameters are read from the image data, and it is determined whether the read image parameters are equal to or less than a predetermined threshold. Based on this determination result, control is performed to adjust the amount of white ink to be applied.

[0017] When calculating the concealment rate of a medium using information about the color of the medium and the density of the white ink, the concealment rate of the medium may be calculated by the following method. The formula for determining whiteness using lightness L* is as follows: (L*_white ink attached area) - (L*_image receiving medium) / (L*_white ink attached area)

[0018] When whiteness is specified by K density*, the formula for calculating the media hiding rate is as follows: (K density * white ink attached area) - (K density * transfer media) / (K density * white ink attached area) K density indicates the K density (visual density) of the spectral density. Visual density is expressed as the common logarithm of the reciprocal of the reflectance weighted by the wavelength response characteristics of the human eye.

[0019] The hiding ratio may also be set as a white difference ΔE as hiding power. ΔE_{(target white), (white ink attached area)} In this embodiment, the term "concealment rate" is used, but it is not important that it is a rate, and it is sufficient if the threshold value of the concealment rate can be specified as a numerical value.

[0020] For example, when the image parameter is equal to or less than a predetermined threshold, the printing device ejects white ink using the calculated amount of white ink applied. This allows the printing device to apply the required amount of white ink to areas that would be affected by the color of the medium. This allows the color of the transferred image to be consistent regardless of the medium while reducing the amount of white ink used.

[0021] Printing may also be referred to as image formation, recording, printing, copying, modeling, etc., and all of these are synonymous terms. When an inkjet printing device is used, the printing system may be referred to as an inkjet system, etc.

[0022] The medium can be selected appropriately, and can be any material to which a liquid can be attached, even temporarily, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, building materials such as wallpaper and flooring, textiles for clothing, signage, etc.

[0023] The printing system of this embodiment includes a discharge unit that discharges color inks and white ink onto a medium, and a control unit that controls the discharge unit. Within the printing system, the discharge unit and the control unit may be separate, or the discharge unit and the control unit may be provided in the same device.

[0024] The system configuration can be selected as appropriate. For example, the system may have a printing device having a discharge unit and a control unit. Alternatively, the printing system may have a printing device having a discharge unit and another device having a control unit that controls the printing device.

[0025] The printing system of this embodiment may or may not include an information processing device (for example, a personal computer, a tablet, a smartphone, etc.) used by the user.

[0026] 1 is a diagram illustrating an example of a printing system 10 according to the present embodiment. The printing system 10 may include an image forming device 2 having a discharge unit and a control unit, as shown in (A). In this case, the image forming device 2 may exchange data with the information processing device 1. The printing system 10 may include an image forming device 2 having a discharge unit and a control device 3 having a control unit, as shown in (B). In this case, the printing system 10 may exchange data with the information processing device 1, or the control device 3 may exchange data with the information processing device 1.

[0027] The information processing device 1, the image forming device 2, and the control device 3 each include, for example, a CPU, a RAM, a ROM, a HDD, an I / F, and the like, as appropriate.

[0028] The ejection unit has a liquid ejection head such as an inkjet head. The number of liquid ejection heads may be one or more. The ejection unit may be of a serial type or a line type.

[0029] The image forming apparatus 2 may have a transport unit that transports the medium. The image forming apparatus 2 may also have a heating unit that heats (may also be referred to as drying) the medium. An example of the heating unit is a heater. The image forming apparatus 2 is an example of a printing apparatus of this embodiment.

[0030] The printing system of this embodiment acquires image data, medium color information, and white ink density information. The term "acquire" may also be referred to as "receive," "collect," or "accept." This data and information may be acquired by the image forming device 2, the control device 3, or another device. For example, this data and information may be acquired from the information processing device 1. This may or may not be via the Internet.

[0031] The printing system of this embodiment may obtain the above data and information from a device other than the information processing device 1. For example, information on the color of the medium may be obtained as a measurement result from a measurement device that measures the color of the medium. Also, for example, information on the density of the white ink may be obtained as a measurement result from a measurement device that measures the density of the white ink.

[0032] The image data may be included in the print command, for example. The medium color information and white ink density information may be included in the print command and transmitted each time, or may be obtained by the system in advance before the print command is transmitted. In this case, the information may be stored in any storage device.

[0033] The control unit calculates the concealment rate of the medium based on the medium color information and the density of the white ink, and also calculates (or may be referred to as determining) the amount of white ink required to conceal the medium. For example, when printing on red polyester fabric, the control unit calculates the concealment rate of the medium using the red color information and the density of the white ink. From the concealment rate of the medium calculated in this manner, the control unit calculates the amount of white ink required to conceal the medium. The amount of white ink that needs to be applied to conceal a medium is sometimes referred to as the minimum amount of white ink that needs to be applied.

[0034] The control unit reads predetermined image parameters from the image data. The control unit performs a threshold determination on the read image parameters. The control unit adjusts the amount of white ink applied based on the determination result. In this way, the necessary amount of white ink can be applied to areas that would be affected by the color of the medium. This makes it possible to reduce the amount of white ink used while also preventing the color of the image from changing depending on the color of the medium.

[0035] In this embodiment, the image parameter is any one selected from the amount of color ink applied and color data measurable by a colorimeter. When these are used as the image parameter, it is easy to read from the image data, it is easy to set a threshold, and it is easy to control the amount of white ink applied. When the image parameter is any one selected from these, it is easy to set a threshold and make threshold judgments, and it is easy to control the amount of white ink applied. In addition, it is possible to prevent the threshold judgment process from becoming complicated. There are no particular restrictions on which image parameter to use, and the optimal image parameter is selected depending on the application.

[0036] The ink deposition amount can also be said to be the amount of ink to be ejected obtained by analyzing input image data. When it is said that the amount of white ink deposition is adjusted, it can also be said that the amount of white ink to be ejected is adjusted. The ink deposition amount can be determined, for example, as follows: By creating a profile at a stage prior to ejection, the relationship between color and color ink deposition amount is calculated. Based on this, the ink deposition amount is determined from the image data.

[0037] The ink deposition amount is expressed in units of %, for example, and in this case, falls within the range of 0 to 100%. An ink deposition amount of 0% is a numerical representation of a state in which not a single droplet of the color ink is ejected from the ejection unit, for example, the nozzles of an inkjet head. An ink deposition amount of 100% is a numerical representation of a state in which the color ink is ejected from all nozzles of an inkjet head at the maximum ejection volume per droplet. The numerical value of the ink deposition amount is determined, for example, by processing image data with a RIP (Raster Image Processor). The deposition amounts of white ink and color inks can be quantified in the same way.

[0038] The color data is data obtained by a general colorimeter. Examples include spectral reflectance, spectral transmittance, and various color values ​​(X, Y, Z, L*, a*, b*, Δa*, Δb*, ΔL*, ΔEab*, YI, etc.). Examples of color data include spectral reflectance, spectral transmittance, lightness, saturation, and density, and it is preferable to select any one of these. These are data obtained by a general colorimeter, which makes it easy to set a threshold value.

[0039] When lightness, saturation, and density are selected as image parameters, they are quantified, for example, as follows. For example, when the image parameter is brightness, the brightest is 0, the darkest is 100, and the range from 0 to 100 is divided into several stages for numerical expression. For example, when the image parameter is saturation, the lowest saturation is set to 0, the highest saturation is set to 100, and the range from 0 to 100 is divided into several stages for numerical expression. For example, when the image parameter is density, the lowest density is set to 0, the highest density is set to 100, and the range from 0 to 100 is divided into several stages for numerical expression.

[0040] As described above, by converting the values ​​into numerical values ​​between 0 and 100, it is possible to reduce the complexity of threshold determination when multiple image parameters are selected. The image parameters may be selected so that an optimal item is selected depending on the application, and each item may have its own numerical range rather than being converted into numerical values ​​between 0 and 100. Furthermore, each item may have its own unique threshold when making threshold determination.

[0041] The method of threshold determination for image parameters read from image data and the control according to the determination results can be selected as appropriate. Examples will be described below. For example, if the image parameter is the amount of color ink adhered, the control unit determines whether the amount of color ink adhered is equal to or greater than a first threshold. If the amount of color ink adhered is equal to or greater than the first threshold, control is performed to eject white ink at a predetermined lower limit of the amount of white ink adhered. An example of the predetermined lower limit of the amount of white ink adhered is the minimum amount of white ink adhered necessary to ensure quality. This can prevent poor drying.

[0042] For example, if the image parameter is color data, the control unit determines whether the color data is equal to or less than a second threshold. If the color data is equal to or less than the second threshold, the control unit controls the ejection of white ink at the calculated amount of applied white ink. The calculated amount of applied white ink is calculated by calculating the concealment rate of the medium based on the color information of the medium and the density of the white ink, as described above, and then calculating the amount of applied white ink required to conceal the medium. In this case, it is possible to prevent the medium from becoming incapable of being concealed.

[0043] In this way, by considering the amount of color ink applied separately from the above-mentioned color data, it is possible to reliably conceal the medium and prevent insufficient ink drying. In this case, it is also possible to prevent excessive ink application, thereby preventing poor drying. Since excessive ink application can cause poor drying, reducing the amount of white ink applied as much as possible can prevent poor drying. The lower limit of the amount of white ink applied varies depending on the type of white ink, the type of transfer substrate, the type of transfer material, the drying means, etc., so it is best to print a chart under different conditions in advance and examine the results.

[0044] The numerical value of the color data is appropriately selected so that the color of the medium is more visible when the color data value is small, and less visible when the color data value is large. This makes it easier to set thresholds for the color data and to make threshold judgments.

[0045] The area in which the image parameters are read and the amount of white ink applied is controlled may be the entire image, but it is preferable to perform this for each predetermined area. That is, it is preferable that the control unit reads the image parameters for each predetermined area, performs threshold determination, and controls the deposition amount of the ejected white ink. By performing this process for each predetermined area, the effects of the present invention can be improved. A larger amount of white ink can be applied to areas where it is necessary to apply a larger amount of white ink to conceal the transfer material. Also, the amount of white ink used can be reduced in areas where it is not necessary to apply a larger amount of white ink. The range of the predetermined region is not particularly limited and can be selected appropriately.

[0046] The white ink is used as a base after an image is formed on a medium, for example. The control unit preferably determines image parameters for the amount of white ink applied to form the base and controls the amount of applied ink. By determining image parameters and controlling the amount of applied white ink, which serves as the base, the influence of the color of the medium can be further reduced.

[0047] The position of the base after an image is formed on the medium is selected appropriately depending on the application of the printed matter, and the white ink layer may be a layer below the color inks or may be a layer above the color inks. The position of the base differs depending on which side of the medium the printed matter is viewed from. For example, if the side from which the ink is ejected is considered the front, when the printed matter is viewed from the front, the order is the medium, the white ink layer, and the color ink layer. When the printed matter is viewed from the back, the order is the medium, the color ink layer, and the white ink layer.

[0048] 2A and 2B are diagrams illustrating examples of adjusting the amount of white ink applied. Fig. 2A shows an example of adjusting the amount of white ink applied based on the amount of color ink applied. Fig. 2B shows an example of adjusting the amount of white ink applied based on color data (denoted as parameter A in the figure).

[0049] In Figure 2, the horizontal axis represents gradation. Although not limited to this, in the illustrated example, the unit of gradation is %. A gradation of 0% means that the density of the corresponding color is 0, and a gradation of 100% means that the corresponding color is at its maximum density. However, the maximum density of the corresponding color depends on the system. The range of gradation from 0 to 100% is divided into stages, and this is used as the horizontal axis in this example. The unit of gradation need not be %, but may be a dimensionless value from 0 to 100. The gradation (horizontal axis) in this example can also be thought of as the amount of color ink applied. Generally, there is a correlation between the amount of applied ink and gradation.

[0050] In FIG. 2, the vertical axis represents the amount of ink adhesion and parameter A. The unit of ink adhesion is %, and the unit of parameter A is dimensionless. In this example, parameter A is treated as a single item. In the example shown in FIG. 2, the vertical axis is written as "adhesion amount, A". Adhesion amount refers to the amount of ink adhesion. As in this example, the ink adhesion amount and color data (parameter A) may be on the same scale. In this example, this scale ranges from 0 to 100. However, this embodiment is not limited to this, and the ink adhesion amount and color data (parameter A) may be on different scales. In this example, there is no point where the ink adhesion amount, parameter A, or gradation exceeds 100 (for example, 100%), but for convenience, the figure shows values ​​up to 120.

[0051] In FIG. 2(A), plot a plots the color ink deposition amount [%]. In this example, the color ink deposition amount [%] is directly proportional to the gradation (e.g., %). Gradation is known to be a number that indicates the number of levels of color density, brightness, etc. that can be expressed. As the gradation increases, the ink deposition amount increases (becomes larger) to express the color density, brightness, etc. Therefore, in the illustrated example, the color ink deposition amount and gradation are in a proportional relationship. Therefore, in this example, the gradation on the horizontal axis can also be considered to be equivalent to the color ink deposition amount [%]. In this example, the color ink deposition amount may also be simply referred to as the ink deposition amount.

[0052] In FIG. 2A, plot b represents the amount of white ink applied [%] adjusted based on the amount of color ink applied. As described above, in this embodiment, for example, it is determined whether the amount of color ink applied is equal to or greater than a first threshold, and if it is equal to or greater than the first threshold, white ink is ejected at a predetermined lower limit of the amount of white ink applied. In the example shown in FIG. 2A, 80% is selected as the first threshold, and threshold determination is performed. In areas where the amount of color ink applied is 80% or more, the minimum amount of white ink applied necessary to ensure quality is applied. Note that in this example, the area where the amount of color ink applied is 80% or more corresponds to an area where the gradation is 80% or more, and is shown by a dashed dotted line.

[0053] In this example, 30% is exemplified as the minimum amount of white ink adhesion necessary to ensure quality. By setting the amount of white ink adhesion to 30% in a region where the amount of color ink adhesion is 80% or more, it is possible to prevent the ink adhesion amount from becoming excessively small, and to prevent, for example, difficulty in adhering adhesive powder. This makes it possible to suppress a decrease in washing fastness and the occurrence of uneven image color, thereby ensuring quality.

[0054] In the region where the amount of applied color ink is less than the first threshold, the amount of applied white ink can be adjusted as appropriate. For example, as shown in plot b, the amount of applied white ink can be controlled to decrease as the amount of applied color ink increases.

[0055] In FIG. 2(B), plot c corresponds to color data. In this example, color data is also referred to as parameter A. Plot c represents the change in parameter A relative to the gradation (horizontal axis). Using density as an example of color data, in this example, a smaller value of color data indicates a lighter color, and a larger value indicates a darker color. Therefore, when the density value as color data is small, the color of the medium is more likely to affect the image. For this reason, in areas where the color data value is small in this example, it is necessary to increase the amount of white ink applied to conceal the color of the medium.

[0056] In FIG. 2(B), plot d represents the amount of white ink applied [%] adjusted based on the color data. As described above, in this embodiment, for example, it is determined whether the color data is equal to or less than the second threshold, and if it is equal to or less than the second threshold, white ink is ejected at an amount of white ink applied calculated based on the color information of the medium and the density of the white ink. In the example shown in FIG. 2(B), 30 is selected as the second threshold and threshold determination is performed. In areas where the color data is equal to or less than 30, the calculated amount of white ink applied is applied. Note that in this example, the area where the color data is equal to or less than 30 corresponds to an area where the gradation is approximately 56% or less, and is shown by the normal dashed line.

[0057] In this example, the calculated amount of white ink applied is 70%. By setting the amount of white ink applied to 70% in areas where the color data is 30 or less, the medium can be reliably concealed.

[0058] In areas where the color data is greater than the second threshold, the amount of applied white ink can be adjusted appropriately. For example, as shown in plot d, the amount of applied white ink is adjusted to be smaller where the color data value is large.

[0059] Figures 3A and 3B are flowcharts for explaining an example of this embodiment. Figure 3A is an example of a flowchart corresponding to the example shown in Figure 2(A), and Figure 3B is an example of a flowchart corresponding to the example shown in Figure 2(B).

[0060] First, FIG. 3A will be described. In S10, the color of the medium is read. In S11, ink information is read in. The ink information includes the density of white ink and other information as necessary. Either S10 or S11 can be performed first.

[0061] The medium color information and ink information are included in, for example, a print instruction from a user, and the system can read the medium color information and ink information by receiving the print instruction. Alternatively, for example, the medium color information and ink information may be stored in advance in any storage means, and read from the storage means when a print instruction is received. The medium color information and ink information may be input by the user or may be determined by measurement.

[0062] In S12, the concealment rate is calculated using the information on the color of the medium and the density of the white ink, and the calculated concealment rate is used to calculate the minimum required amount of white ink to be applied.

[0063] In S13, the image data is read. The image data may be included in a print instruction from a user, for example. The image data may be stored in any storage means and read from the storage means. When image data is read, image parameters in the image data are read.

[0064] In S14, the sRGB values ​​of the image data are converted into CMYK values, which makes it easier to eject color inks of CMYK, for example.

[0065] In S15, it is determined whether the amount of color ink attached is equal to or greater than a set threshold. This threshold is the first threshold mentioned above. If the determination result is YES, S16 is performed. If the determination result is NO, S16 is not performed and the process proceeds to S17.

[0066] In S16, the amount of white ink applied is adjusted. If the amount of color ink applied is equal to or greater than a set threshold, a preset amount of white ink applied that can guarantee quality is set. Note that if the determination in S16 is YES, this corresponds to the area in FIG. 2(A) where the amount of color ink applied is 80 or greater (for example, an area where the gradation is greater than around 80).

[0067] In S17, printing is performed on the medium.

[0068] Next, Fig. 3B will be described. Explanation of parts that can be shared with Fig. 3A will be omitted. Here, the determination process after S14 will be described.

[0069] In S18, it is determined whether the color data is equal to or less than a set threshold value. This threshold value is the second threshold value described above. If the determination result is YES, S19 is performed. If the determination result is NO, S19 is not performed and the process proceeds to S17.

[0070] In S19, the amount of white ink applied is adjusted. If the color data is equal to or less than the set threshold, the amount of white ink applied is set to the amount calculated in S12. If the determination in S18 is YES, this corresponds to the area where A in FIG. 2(B) is 30 or less (for example, an area where the gradation is about 56% or less).

[0071] In S17, printing is performed on the medium.

[0072] According to the printing system, printing device, and printing method of this embodiment, it is possible to reduce the amount of white ink used while preventing the color of the medium from showing through, and to prevent the color of the image from changing depending on the color of the medium.

[0073] Next, we will provide additional information about an example of adjusting the amount of white ink applied, shown in plots b and d. Plots b and d represent the amount of white ink applied [%] adjusted based on the amount of color ink applied and color data. In this example, the following conditions (1) to (4) are used to adjust the amount of white ink applied. (1) Minimum amount of white ink required to ensure quality: 30% (2) Color ink adhesion amount at which ink drying is insufficient: 80% or more (3) Required amount of white ink calculated from the media's concealment rate: 70% (4) Conditions for color data (parameter A) that allows the color of the medium to show through: A must be 30 or greater.

[0074] Condition (1) specifies the minimum amount of white ink applied necessary to ensure quality. If the amount of ink applied is small, for example, it becomes difficult to apply powder, which can lead to concerns about reduced washing fastness and uneven image color. For this reason, a lower limit is set for the amount of white ink applied, as in condition (1). Because quality, such as uneven color, varies depending on the combination of ink and medium, it is preferable to print charts with different ink application amounts for each ink and medium, and then consider the results before setting condition (1).

[0075] Condition (2) defines the amount of color ink adhesion that will cause insufficient ink drying. When the gradation (for example, the amount of color ink adhesion) is large, the amount of color ink on the medium increases, so sufficient drying is necessary. For this reason, in areas where the amount of color ink adhesion is large, the amount of white ink adhesion is reduced to prevent obscuring. Since the amount of ink adhesion that will cause insufficient ink drying varies depending on the drying method and type of ink, it is preferable to print a chart by changing the drying time and drying strength of the drying method and the amount of ink adhesion for each ink, and then examine the results to set condition (2).

[0076] Condition (3) specifies the required amount of white ink applied, calculated from the coverage ratio of the medium. Condition (3) is the condition set in S12 of Figures 3A and 3B, for example. The coverage ratio is calculated from information on the color of the medium and information on the density of the white ink, and this is used to calculate the required amount of white ink applied.

[0077] Condition (4) specifies the conditions for color data that allow the color of the medium to show through. For example, colors with low brightness (large color data values) are less likely to allow the color of the medium to show through, but colors with high brightness (small color data values) are more likely to allow the color of the medium to show through. Since the conditions for color show through vary depending on the type of color data, the color of the medium, the type of ink, etc., it is recommended to print and examine each chart before setting condition (4). In addition to brightness, for example, when the density is high (a large value in terms of color data), the color of the medium is less likely to show through, but when the density is low (a small value in terms of color data), the color of the medium is more likely to show through.

[0078] A specific example of digitizing the color data (parameter A) in Fig. 2(B) will be described below. In Fig. 2(B), the value of the color data, 0 to 100, is set by calculating, for example, the HSV value or RGB value contained in the image data.

[0079] As in S18 of Figures 2(B) and 3B described above, threshold judgment is performed to determine whether the color data satisfies condition (4). In other words, it is determined whether the color data is 30 or less. Where the gradation is approximately 56 or less (the area surrounded by the normal dashed line), the color data (plot c) is 30 or less, so it is expected that the color of the medium will show through. Therefore, where the gradation is approximately 56 or less, condition (3) is applied, i.e., the minimum required amount of white ink applied (70%) calculated from the hiding rate. Therefore, plot d (amount of white ink applied) is adjusted to 70% where the gradation is approximately 56 or less (the area surrounded by the normal dashed line). This prevents the color of the medium from showing through.

[0080] As shown in S15 of Figures 2(A) and 3A above, threshold determination is performed, and the area where the color ink adhesion amount is approximately 80% or more corresponds to condition (2), and since the ink adhesion amount is large, it is desirable to consider drying. Therefore, condition (1) is applied to the area where the color ink adhesion amount is approximately 80% or more. Therefore, plot b (white ink adhesion amount) is adjusted to 30% where the gradation is approximately 80 or more (area surrounded by the dashed dotted line).

[0081] Generally, when printing on a transfer substrate (e.g., film) in DTF, there is a demand for lowering the drying temperature of the drying means (also called heating means), such as a heater, applied to the printed area. Lower drying temperatures improve the wettability of the printed area, resulting in better color development and stable ejection performance from the liquid ejection head. However, lower drying temperatures can result in insufficient drying of color ink in areas with a high ink deposition volume. This can result in ink bleeding, repellency, bleeding, and other problems. Simply reducing the amount of ink deposition can result in the color of the transfer material showing through.

[0082] In this example, in areas where there is a large amount of color ink attached and there is a possibility that the color ink may not dry sufficiently, the amount of white ink attached is reduced while ensuring a minimum amount of white ink attached. This prevents the color of the medium from showing through, and by limiting the amount of white ink attached, it is possible to prevent the color from not drying sufficiently and prevent ink from running due to insufficient drying.

[0083] In this way, in this embodiment, by adjusting the amount of white ink applied, it is possible to prevent the color of the image from changing depending on the color of the medium without using an excessive amount of white ink. Furthermore, even when white ink is used to prevent the color of the medium from showing through, it is possible to improve the drying properties and ensure good quality.

[0084] As described above, in this embodiment, it is preferable to perform threshold determination of image parameters and adjustment of the amount of white ink applied for each predetermined region. By adjusting the amount of white ink applied for each region, it is possible to apply the minimum amount of white ink necessary to prevent the color of the medium from showing through in each region, and to optimize the amount of white ink used for each region. This makes it possible to reduce the amount of white ink used, achieving favorable results in terms of cost. Furthermore, adjusting the amount of white ink applied for each region makes it easier to address ink flow.

[0085] (Second embodiment) Next, other embodiments of the present invention will be described. In the examples described in the above embodiments, the threshold determination of the image parameters is mainly performed using either the amount of applied color ink or the color data. However, the present invention is not limited to this, and both the amount of applied color ink and the color data may be used as image parameters, or both the amount of applied color ink and the color data may be used to perform the threshold determination of the image parameters.

[0086] Fig. 4 is a diagram for explaining an example of adjusting the amount of white ink applied in this embodiment. Fig. 4 is a plot similar to Fig. 2, and the horizontal and vertical axes are the same as those in Fig. 2. Plots a and c in Fig. 4 are the same as plots a and c in Fig. 2. Plot a is the amount of color ink applied, and plot c is color data. Plot e is the amount of white ink applied.

[0087] 2(A), in this example, a determination is made as to whether the amount of color ink applied is equal to or greater than a first threshold (e.g., 80 or greater), and if it is equal to or greater than the first threshold, it is preferable to apply the minimum amount of white ink applied necessary to ensure quality (e.g., 30%). In areas where the amount of color ink applied is around 80% or greater (areas where the gradation is around 80% or greater, the area surrounded by the dashed-dotted line), the color data (plot c) exceeds 30, so it is expected that there will be no effect from the color of the transfer material even if condition (3) is not applied.

[0088] Also in this example, as in Figure 2(B), it is preferable to determine whether the color data is below a second threshold (for example, below 30), and if it is below the second threshold, to apply the calculated amount of white ink applied required for concealment (for example, 70%).

[0089] In this example, both a threshold determination of the color ink deposition amount and a threshold determination of the color data are performed. Therefore, as shown in plot e in Figure 4, a white ink deposition amount of 30% is applied in areas where the color ink deposition amount is equal to or greater than the first threshold (areas where the gradation is 80% or greater, areas indicated by the dashed line), and a white ink deposition amount of 70% is applied in areas where the color data is equal to or less than the second threshold (areas where the gradation is approximately 56% or less, areas indicated by the regular dashed line).

[0090] FIG. 5 is a flowchart for explaining an example of this embodiment. In FIG. 5, processes common to FIGS. 3A and 3B are assigned the same reference numerals, and a description of the process content will be omitted here. In the example shown in FIG. 5, a threshold determination of the color ink deposition amount (S15) and a threshold determination of the color data (S18) are performed within the same flow. As a result, the white ink deposition amount is adjusted as shown in plot e in FIG. 4.

[0091] In this way, the threshold value determination of the image parameters may be performed using both the amount of color ink applied and the color data.

[0092] A supplementary explanation will be given below regarding the flow shown in Figure 5. In the example flow described above, the determinations in S18 and S15 are performed, with the determination in S18 (color data determination) being performed first and the determination in S15 (color ink adhesion amount determination) being performed later. In the example shown in FIG. 4, it is assumed that one of S18 and S15 will result in a YES, but this embodiment is not limited to this. Both determination results may result in a YES. In this case, it is possible to determine which determination is given priority by determining whether the determination in S15 (color ink adhesion amount determination) is performed first or the determination in S18 (color data determination) is performed first.

[0093] 5, the determination of the amount of applied color ink (S15) is performed later, so priority is given to the process (S16) when the determination result of the amount of applied color ink is YES. For example, if the determination in S18 (color data determination) is YES and the amount of applied white ink is adjusted (S19), and the determination in S15 (color ink application amount determination) is YES and the amount of applied white ink is adjusted (S16), the adjustment in S16 is reflected. Which determination is performed first (later) can be selected as appropriate, taking into account the use of the printed matter, etc.

[0094] In the example shown in Figure 4, the amount of white ink applied (plot e) is continuously changed where the gradation is greater than approximately 56% and less than approximately 80%. That is, when the gradation is near 50%, the amount of white ink applied (plot e) is set to 70%, and as the gradation increases toward 80%, the amount of white ink applied approaches 30%. While it can be said that the influence of the color of the medium is small where the color data is greater than 30 and close to 30, the influence of the color of the medium can be more reliably prevented by ejecting white ink in an amount close to the required amount of white ink applied calculated from the concealment rate of the medium (70% of condition (3)).

[0095] To reiterate this, when the color data is greater than the second threshold (30, condition (4) in this example) and the amount of color ink deposition is less than the first threshold (80, condition (2) in this example), it is preferable to gradually reduce the amount of white ink deposition from the amount of white ink deposition when the color data is equal to or less than the second threshold (70%, condition (3) in this example) toward the amount of white ink deposition when the amount of color ink deposition is equal to or greater than the first threshold (30%, condition (1) in this example).

[0096] (Third embodiment) Next, another embodiment of the present invention will be described. When the amount of ink adhered to adjacent areas differs significantly, ink may flow into an area with a smaller amount of ink adhered to it. When this ink flow occurs, image quality deteriorates. In this embodiment, adjacent areas are compared, and the amount of ink adhered to the adjacent areas is adjusted so that the difference in the amount of ink adhered to the adjacent areas is reduced. This prevents ink flow.

[0097] Figure 6 is a diagram for explaining ink flow. (A) shows the state before ink flow occurs, and (B) shows the state after ink flow occurs. Ink flows from the area with a large amount of ink adhesion (100%) (left side of the figure) to the area with a small amount of ink adhesion (30%) (right side of the figure).

[0098] In this embodiment, the difference in the amount of ink adhered between adjacent regions is reduced, thereby suppressing ink flow. One way to reduce the difference in the amount of ink adhered between adjacent regions is to use a method of gradating the amount of ink adhered to the boundary between adjacent regions. Another method is to apply transparent ink. When applying the amount of transparent ink, it is preferable to adjust the amount of transparent ink adhered.

[0099] In this embodiment, the amount of white ink applied to the corresponding area is constant. Therefore, the above-mentioned ink application amount can be considered to be the amount of color ink applied. Note that adjacent area and adjacent area have the same meaning. For example, the amount of clear ink applied to an area with a small amount of ink application is increased.

[0100] 7 is a diagram for explaining an example of gradation processing. For example, in an area (right side in the figure) where the ink adhesion amount is 30%, the ink adhesion amount is gradually increased at the boundary with the adjacent area (left side in the figure) as it approaches the adjacent area. In this way, it is possible to reduce the difference in ink adhesion amount between adjacent areas. Alternatively, in an area where the ink deposition amount is 100% (left side in the drawing), the ink deposition amount may be gradually reduced at the boundary with the adjacent area (right side in the drawing) as it approaches the adjacent area.

[0101] Fig. 8 is a flowchart for explaining an example of this embodiment. Explanations of parts common to Figs. 3A, 3B, and 5 will be omitted. Note that the example shown in Fig. 8, like the example shown in Fig. 5, is an example in which the color ink adhesion amount threshold determination (S15) and the color data threshold determination (S18) are performed within the same flow. However, this embodiment is not limited to this, and, like Figs. 3A and 3B, it is also possible to perform either the color ink adhesion amount threshold determination (S15) or the color data threshold determination (S18).

[0102] In S20, it is determined whether the total ink adhesion amount in the adjacent areas is within a threshold value. In other words, in this example, after adjusting the amount of white ink adhesion, the total ink adhesion amount is calculated for each specified area, and the total ink adhesion amounts in the adjacent areas are compared. If the total ink adhesion amount in the adjacent areas is within the threshold value, printing (S17) is performed without performing S21. If the total ink adhesion amount in the adjacent areas is equal to or greater than the threshold value, S21 is performed for that location and the adjacent areas.

[0103] In S21, gradation processing is performed on the adjacent portions. In the gradation processing in this example, the amount of color ink applied is adjusted for one or both of the two adjacent areas.

[0104] In S17, printing is performed on the medium. Thus, according to the printing system of this embodiment, by adjusting the amount of ink adhered so that the difference in the amount of ink adhered does not become too large, in addition to the effects obtained in the above embodiment, it is possible to prevent a decrease in image quality due to ink flow.

[0105] The above flow has been explained using gradation processing as an example, but other methods, such as using transparent ink, may also be used for adjustment. By adjusting the amount of transparent ink applied so that the difference in ink application amount between adjacent areas is equal to or less than a predetermined threshold, ink bleeding can be prevented.

[0106] This embodiment will be described again. In this embodiment, the control unit calculates the total ink deposition amount, which is the sum of the ink deposition amounts of each ink, for each specified area, and if the difference in the total ink deposition amount between adjacent areas is equal to or greater than a specified threshold, performs gradation processing by adjusting the deposition amount of color ink so that the difference in the total ink deposition amount between adjacent areas is smaller than the specified threshold.

[0107] In this embodiment, in addition to the above, the following may also be done. In this embodiment, the ejection unit is capable of ejecting transparent ink, and the control unit calculates the total ink adhesion amount, which is the sum of the ink adhesion amounts of each ink, for each specified area, and if the difference in the total ink adhesion amount between adjacent areas is equal to or greater than a specified threshold, adjusts the adhesion amount of transparent ink so that the difference in the total ink adhesion amount between adjacent areas is smaller than the specified threshold.

[0108] (Fourth embodiment) Next, another embodiment of the present invention will be described. In this embodiment, ink is ejected onto a transfer substrate. Explanation of matters similar to those in the above embodiment will be omitted.

[0109] The printing system of this embodiment is a printing system having an ejection unit that ejects color ink and white ink onto a transfer substrate, and a control unit that controls the ejection unit, and the color ink and white ink ejected onto the transfer substrate are transferred to a transfer recipient material. The printing system obtains image data, color information of the transfer recipient material, and information on the density of the white ink. The control unit calculates a concealment rate of the transfer recipient material based on the color information of the transfer recipient material and the density of the white ink, calculates the amount of white ink adhesion necessary to conceal the transfer recipient material based on the calculated concealment rate, and reads the following image parameters in the image data, performs threshold judgment on the read image parameters, and adjusts the amount of white ink adhesion based on the judgment result. [Image parameters] The image parameters are one or more selected from the color ink deposition amount and color data measurable by a colorimeter.

[0110] The printing device of this embodiment is a printing device having an ejection unit that ejects color ink and white ink onto a transfer substrate and a control unit that controls the ejection unit, and the color ink and white ink ejected onto the transfer substrate are transferred to a transfer recipient material. The printing device obtains image data, color information of the transfer recipient material, and information on the density of the white ink. The control unit calculates the concealment rate of the transfer recipient material based on the color information of the transfer recipient material and the density of the white ink, calculates the amount of white ink adhesion necessary to conceal the transfer recipient material based on the calculated concealment rate, and reads the following image parameters in the image data, performs threshold judgment on the read image parameters, and adjusts the amount of white ink adhesion based on the judgment result. [Image parameters] The image parameters are one or more selected from the color ink deposition amount and color data measurable by a colorimeter.

[0111] The printing method of this embodiment includes a discharging step of discharging color inks and white ink onto a transfer substrate by a printing device, and a control step of controlling the discharge of the color inks and white ink, wherein the color inks and white ink discharged onto the transfer substrate are transferred to a transfer-receiving material, and the printing method obtains image data, color information of the transfer-receiving material, and information on the density of the white ink, and the control step calculates a concealment rate of the transfer-receiving material based on the color information of the transfer-receiving material and the density of the white ink, calculates an amount of the white ink applied that is necessary to conceal the transfer-receiving material based on the calculated concealment rate, reads the following image parameters from the image data, performs threshold judgment on the read image parameters, and adjusts the amount of white ink applied based on the judgment result: [Image parameters] The image parameters are one or more selected from the color ink deposition amount and color data measurable by a colorimeter.

[0112] In this embodiment, the concealment ratio of the transfer material is calculated using information on the color of the transfer material and the density of the white ink, and the calculated concealment ratio is used to calculate the amount of white ink to be applied to conceal the transfer material. Furthermore, image parameters are read from the image data, and it is determined whether the read image parameters are equal to or less than a predetermined threshold. Based on this determination result, control is performed to adjust the amount of white ink to be applied.

[0113] For example, if the image parameter is equal to or less than a predetermined threshold, the white ink is ejected using the calculated amount of white ink applied. This allows the necessary amount of white ink to be applied to areas that would be affected by the color of the transfer material. This allows the color of the transferred image to be consistent regardless of the transfer material while reducing the amount of white ink used.

[0114] The printing system of this embodiment is suitably applied to DTF (Direct To Film) printing.

[0115] The ink ejected onto the transfer substrate is transferred onto the transfer receiving material, or it may be said that the image formed on the transfer substrate is transferred onto the transfer receiving material. The transfer substrate can be appropriately selected, and for example, a film is preferably used. The transfer material can be appropriately selected, and examples thereof include cloth such as a T-shirt. Examples of cloth include polyester fabric. The transfer material may also be referred to as a printed material.

[0116] The method for transferring the image formed on the transfer substrate to the transfer receiving material is not particularly limited and can be selected appropriately. For example, the image formed on the transfer substrate is sprinkled with adhesive powder, the transfer substrate and the transfer receiving material are overlapped, and the image is transferred by applying heat or pressure as necessary.

[0117] The printing system of this embodiment includes a discharge unit that discharges color inks and white ink onto a transfer substrate, and a control unit that controls the discharge unit. Within the printing system, the discharge unit and the control unit may be separate, or the discharge unit and the control unit may be provided in the same device.

[0118] The system configuration can be the same as that of the first embodiment, so here we will mainly explain the differences from the first embodiment. In the first embodiment, ink was ejected onto a medium, but in this embodiment, ink is ejected onto a substrate for transfer. In addition, in this embodiment, information on the color of the transfer material is obtained and the hiding rate of the transfer material is calculated.

[0119] The printing system of this embodiment obtains image data, color information of the transfer material, and density information of the white ink. The printing system of this embodiment may also obtain the above data and information from a device other than the information processing device 1. For example, the printing system may obtain color information of the transfer material as a measurement result from a measuring device that measures the color of the transfer material.

[0120] The image data may be included in the print command, for example. The information on the color of the transfer material and the information on the density of the white ink may be included in the print command and transmitted each time, or may be obtained by the system in advance before the print command is transmitted.

[0121] The control unit calculates the concealment rate of the transfer material based on the color information of the transfer material and the density of the white ink, and also calculates the amount of white ink required to conceal the transfer material. For example, when transferring onto a red polyester fabric, the concealment rate of the transfer target material is calculated using the red color information and the density of the white ink. From the concealment rate of the transfer target material thus calculated, the amount of white ink required to conceal the transfer target material is calculated. The amount of white ink that is required to conceal the transfer material is sometimes referred to as the minimum amount of white ink that is required to conceal the transfer material.

[0122] The control unit reads predetermined image parameters from the image data. The control unit performs threshold determination on the read image parameters. The control unit adjusts the amount of white ink applied based on the determination result. In this way, the necessary amount of white ink can be applied to areas that would be affected by the color of the transfer material. This makes it possible to reduce the amount of white ink used while also preventing the color of the image from changing depending on the color of the transfer material.

[0123] The image parameters in this embodiment can be the same as those in the first embodiment, and therefore a description thereof will be omitted.

[0124] The method of performing threshold determination for image parameters read from image data can be the same as in the first embodiment. For example, the control unit determines whether the amount of adhered color ink is equal to or greater than a first threshold. If the amount of adhered color ink is equal to or greater than the first threshold, the control unit controls the ejection of white ink at a predetermined lower limit of the amount of adhered white ink. An example of the predetermined lower limit of the amount of adhered white ink is the minimum amount of adhered white ink necessary to ensure quality. This can prevent poor drying.

[0125] For example, the control unit determines whether the color data is equal to or less than a second threshold value. If the color data is equal to or less than the second threshold value, the control unit controls the ejection of white ink at the calculated amount of white ink deposition. As described above, the calculated amount of white ink deposition is calculated by calculating the concealment rate of the transferred material based on the color information of the transferred material and the density of the white ink, and then calculating the amount of white ink deposition required to conceal the transferred material. In this case, it is possible to prevent the transferred material from being unable to be concealed.

[0126] In this way, by separately considering the amount of color ink applied and the color data, it is possible to reliably conceal the transfer material and prevent the ink from drying insufficiently.

[0127] Fig. 9 is a flowchart for explaining an example of this embodiment. Explanations of parts common to Figs. 3A, 3B, and 5 will be omitted. Note that the example shown in Fig. 9, like the example shown in Fig. 5, is an example in which the color ink adhesion amount threshold determination (S15) and the color data threshold determination (S18) are performed within the same flow. However, this embodiment is not limited to this, and, like Figs. 3A and 3B, it is also possible to perform either the color ink adhesion amount threshold determination (S15) or the color data threshold determination (S18).

[0128] In S22, the color of the transfer material is read. The color information and ink information of the transfer material are, for example, included in a print instruction from the user, and the system can read the color information and ink information of the transfer material by receiving the print instruction. Alternatively, for example, the color information and ink information of the transfer material may be stored in advance in any storage means, and read from the storage means when a print instruction is received. The color information and ink information of the transfer material may be input by the user, or may be determined by measurement.

[0129] In S12, the concealment ratio is calculated using the color information of the transfer material and the density of the white ink, and the calculated concealment ratio is used to calculate the minimum required amount of white ink to be applied. Note that the term "calculation" here may also be referred to as "determination."

[0130] As in FIGS. 3A, 3B, and 5, threshold determination is performed in S15 and S18, and the amount of white ink applied is adjusted based on the determination results. In this way, the printing system of this embodiment can also prevent the color of the transfer material from showing through while minimizing the amount of white ink used, thereby preventing the color of the image from changing depending on the color of the transfer material. Using lightness as an image parameter, for example, when the lightness of a color is lower than a certain value, the color of the transfer material is less likely to show through, so the color of the transfer material can be prevented from showing through without increasing the amount of white ink applied. On the other hand, when the lightness of a color is higher than a certain value, the color of the transfer material is more likely to show through, so the calculated amount of white ink applied is adjusted so that it is ejected at the lower limit. This prevents the color of the transfer material from showing through, and prevents the color of the image from changing depending on the color of the transfer material. In addition to brightness, for example, when the density is higher than a certain value, the color of the transferred material is less likely to show through, and when the density is lower than a certain value, the color of the transferred material is more likely to show through.

[0131] In this embodiment, too, the amount of white ink applied can be adjusted, as shown in FIG. 2 above. In the description of the first embodiment above, the term "medium" is replaced with "transfer-receiving material" as appropriate. For example, condition (3) is replaced with the required amount of white ink applied calculated from the concealment rate of the transfer-receiving material. Furthermore, for example, condition (4) is replaced with the image parameter condition that allows the color of the transfer-receiving material to show through.

[0132] In the explanation of condition (1), it can be considered that the quality of color unevenness in this embodiment differs depending on the combination of ink and transfer material. Therefore, charts are printed with different ink deposition amounts for each ink and transfer material, and condition (1) is set based on the results.

[0133] Similar to the first embodiment, an example of adjusting the amount of white ink applied in this embodiment (plots b, d, and e) will be described with reference to FIGS.

[0134] For example, a threshold determination of the color data is performed as in S18 of FIG. 9. In this example, it is determined whether the color data satisfies condition (4). In other words, it is determined whether the color data is 30 or less. Where the gradation is around 56 or less (the area surrounded by the normal dashed line), the color data (plot c) is 30 or less, so it is expected that the color of the transferred material will show through. Therefore, where the gradation is around 56 or less, condition (3) is applied, i.e., the minimum required amount of white ink applied (70%) calculated from the hiding rate. Therefore, plot c (amount of white ink applied) is adjusted to 70% where the gradation is around 56 or less (the area surrounded by the normal dashed line). This prevents the color of the transferred material from showing through.

[0135] The area where the amount of color ink applied is around 80% or more can be said to be an area where the gradation is around 80% or more, and is the area surrounded by the dashed dotted line. When a threshold judgment is made on the color data in this area, the color data (plot c) exceeds 30, so it is assumed that there will be no influence from the color of the transferred material even if condition (3) is not applied.

[0136] On the other hand, the area where the amount of color ink applied is around 80% or more corresponds to condition (2), and since the amount of ink applied is large, it is desirable to consider drying. Therefore, for example, as in S15 in Figure 9, a threshold judgment is performed on the amount of color ink applied, and condition (1) is applied to the area where the amount of color ink applied is around 80% or more. Therefore, plots b and e (amount of white ink applied) are adjusted to 30% where the gradation is around 80 or more (area surrounded by the dashed line).

[0137] Generally, when printing on a transfer substrate (e.g., film) in DTF, there is a demand for lowering the drying temperature of the drying means (also called heating means), such as a heater, applied to the printed area. Lower drying temperatures improve the wettability of the printed area, resulting in better color development and stable ejection performance from the liquid ejection head. However, lower drying temperatures can result in insufficient drying of color ink in areas with a high ink deposition volume. This can result in ink bleeding, repellency, bleeding, and other problems. Simply reducing the amount of ink deposition can result in the color of the transfer material showing through.

[0138] In this example, in areas where there is a large amount of color ink attached and there is a possibility that the color ink may not dry sufficiently, the amount of white ink attached is reduced while ensuring a minimum amount of white ink attached. This prevents the color of the transfer material from showing through, and by limiting the amount of white ink attached, it is possible to prevent the color from not drying sufficiently and prevent ink from running due to insufficient drying.

[0139] By adjusting the amount of white ink applied in this way, it is possible to prevent the color of the image from changing depending on the color of the transfer material without using an excessive amount of white ink. Furthermore, even when white ink is used to prevent the color of the transfer material from showing through, it is possible to improve the drying properties and ensure good quality.

[0140] As with the first embodiment, in this embodiment, it is preferable to read image parameters for each predetermined region, perform threshold determination, and control the amount of white ink to be ejected. By adjusting the amount of white ink to be applied for each region, it is possible to apply the minimum amount of white ink necessary to prevent the color of the transfer material from showing through to each region, and to optimize the amount of white ink used for each region. This reduces the amount of white ink used, and also provides favorable results from a cost perspective. Furthermore, adjusting the amount of white ink to be applied for each region makes it easier to deal with ink flow.

[0141] (Fifth embodiment) Next, another embodiment of the present invention will be described. In this embodiment, adjacent regions are compared in the above-described fourth embodiment, and the amount of ink adhesion is adjusted so that the difference in the amount of ink adhesion between the adjacent regions is reduced. In other words, in this embodiment, the amount of ink adhesion is adjusted in the same manner as in the above-described second embodiment in the above-described fourth embodiment. According to this embodiment, ink flow can be prevented even in the case of the DTF method.

[0142] In this embodiment, the medium in the description of the third embodiment and the description of the fourth embodiment is appropriately read as the transfer material. Since this embodiment can be similar to the above embodiments, most of the description will be omitted and only a part will be described.

[0143] 7 to 9 can also be applied to this embodiment. In order to reduce the difference in the amount of ink adhered between adjacent regions, for example, there is a method of applying a gradation to the amount of ink adhered to the boundary between adjacent regions. Another method is to apply transparent ink. When applying the amount of transparent ink adhered, it is preferable to adjust the amount of transparent ink adhered.

[0144] This embodiment will be described again. In this embodiment, the control unit calculates the total ink deposition amount, which is the sum of the ink deposition amounts of each ink, for each specified area, and if the difference in the total ink deposition amount between adjacent areas is equal to or greater than a specified threshold, performs gradation processing by adjusting the deposition amount of color ink so that the difference in the total ink deposition amount between adjacent areas is smaller than the specified threshold.

[0145] In this embodiment, in addition to the above, the following may also be done. In this embodiment, the ejection unit is capable of ejecting transparent ink, and the control unit calculates the total ink adhesion amount, which is the sum of the ink adhesion amounts of each ink, for each specified area, and if the difference in the total ink adhesion amount between adjacent areas is equal to or greater than a specified threshold, adjusts the adhesion amount of transparent ink so that the difference in the total ink adhesion amount between adjacent areas is smaller than the specified threshold.

[0146] For example, aspects of the present invention are as follows. <1> A printing system having an ejection unit that ejects color inks and white ink onto a medium, and a control unit that controls the ejection unit, The printing system obtains image data, information about the color of the medium, and information about the density of the white ink; The control unit calculates a concealment rate of the medium based on information about the color of the medium and the density of the white ink, calculates the amount of white ink to be applied that is necessary to conceal the medium based on the calculated concealment rate, reads the following image parameters from the image data, performs threshold determination on the read image parameters, and adjusts the amount of white ink to be applied based on the determination result: A printing system characterized by: [Image parameters] The image parameters are one or more selected from the color ink deposition amount and color data measurable by a colorimeter. <2> A printing system having a discharge unit that discharges color inks and white ink onto a transfer substrate, and a control unit that controls the discharge unit, the color ink and the white ink ejected onto the transfer substrate are transferred onto a transfer receiving material, The printing system obtains image data, information on the color of the transfer material, and information on the density of the white ink, The control unit calculates the concealment rate of the transfer material based on information on the color of the transfer material and the density of the white ink, calculates the amount of white ink to be applied that is necessary to conceal the transfer material based on the calculated concealment rate, reads the following image parameters from the image data, performs threshold determination on the read image parameters, and adjusts the amount of white ink to be applied based on the determination result: A printing system characterized by: [Image parameters] The image parameters are one or more selected from the color ink deposition amount and color data measurable by a colorimeter. <3> The color data is spectral reflectance, spectral transmittance, brightness, saturation, or density. Characterized by <1> or <2> 2. A printing system according to claim 1 . <4> the image parameter is the amount of color ink applied, The control unit determines whether the amount of adhered color ink is equal to or greater than a first threshold, and if the amount of adhered color ink is equal to or greater than the first threshold, performs control to eject white ink at a predetermined lower limit value of the amount of adhered white ink. Characterized by <1> or <2> 2. A printing system according to claim 1 . <5> the image parameters are the color data, The control unit determines whether the color data is equal to or less than a second threshold value, and if the color data is equal to or less than the second threshold value, performs control to eject white ink in the calculated amount of applied white ink. Characterized by <1> or <2> 2. A printing system according to claim 1 . <6> The control unit reads the image parameters for each predetermined area, performs threshold determination, and controls the amount of white ink to be discharged. Characterized by <1> from <5> 10. The printing system according to claim 9, wherein: <7> The control unit calculates a total ink deposition amount, which is the sum of the ink deposition amounts of each ink, for each predetermined area, and when the difference in the total ink deposition amounts between adjacent areas is equal to or greater than a predetermined threshold, performs gradation processing by adjusting the deposition amounts of color inks so that the difference in the total ink deposition amounts between adjacent areas becomes smaller than the predetermined threshold. Characterized by <1> from <6> 10. The printing system according to claim 9, wherein: <8> the ejection unit is capable of ejecting transparent ink, The control unit calculates a total ink deposition amount, which is the sum of the ink deposition amounts of each ink, for each predetermined area, and if the difference in the total ink deposition amounts between adjacent areas is equal to or greater than a predetermined threshold, adjusts the deposition amount of transparent ink so that the difference in the total ink deposition amounts between adjacent areas becomes smaller than the predetermined threshold. Characterized by <1> from <6> 10. The printing system according to claim 9, wherein: <9> the white ink is used as a base after an image is formed on the medium, The control unit determines the image parameters for the amount of white ink applied as a base and controls the amount of applied white ink. Characterized by <1> 2. A printing system according to claim 1 . <10> the white ink is used as a base after the ink is transferred to the transfer material, The control unit determines the image parameters for the amount of white ink applied as a base and controls the amount of applied white ink. Characterized by <2> 2. A printing system according to claim 1 . <11> A printing device having a discharge unit that discharges color inks and white ink onto a medium, and a control unit that controls the discharge unit, The printing device obtains image data, information on the color of the medium, and information on the density of the white ink; The control unit calculates a concealment rate of the medium based on information about the color of the medium and the density of the white ink, calculates the amount of white ink to be applied that is necessary to conceal the medium based on the calculated concealment rate, reads the following image parameters from the image data, performs threshold determination on the read image parameters, and adjusts the amount of white ink to be applied based on the determination result: A printing device characterized by: [Image parameters] The image parameters are one or more selected from the color ink deposition amount and color data measurable by a colorimeter. <12> A printing device having a discharge unit that discharges color inks and white ink onto a transfer substrate, and a control unit that controls the discharge unit, the color ink and the white ink ejected onto the transfer substrate are transferred onto a transfer receiving material, The printing device obtains image data, information on the color of the transfer material, and information on the density of the white ink, The control unit calculates the concealment rate of the transfer material based on information on the color of the transfer material and the density of the white ink, calculates the amount of white ink to be applied that is necessary to conceal the transfer material based on the calculated concealment rate, reads the following image parameters from the image data, performs threshold determination on the read image parameters, and adjusts the amount of white ink to be applied based on the determination result: A printing device characterized by: [Image parameters] The image parameters are one or more selected from the color ink deposition amount and color data measurable by a colorimeter. <13> A printing method including a discharge step of discharging color inks and white ink onto a medium by a printing device, and a control step of controlling the discharge of the color inks and the white ink, The printing method includes obtaining image data, information on the color of the medium, and information on the density of the white ink; The control step calculates a concealment rate of the medium based on information about the color of the medium and the density of the white ink, calculates the amount of white ink to be applied that is necessary to conceal the medium based on the calculated concealment rate, reads the following image parameters from the image data, performs threshold determination on the read image parameters, and adjusts the amount of white ink to be applied based on the determination result: A printing method characterized by: [Image parameters] The image parameters are one or more selected from the color ink deposition amount and color data measurable by a colorimeter. <14> A printing method including a discharging step of discharging color inks and white ink onto a transfer substrate by a printing device, and a control step of controlling the discharge of the color inks and the white ink, the color ink and the white ink ejected onto the transfer substrate are transferred onto a transfer receiving material, The printing method includes obtaining image data, information on the color of the transfer material, and information on the density of the white ink; The control step calculates a concealment rate of the transfer material based on information on the color of the transfer material and the density of the white ink, calculates the amount of white ink to be applied that is necessary to conceal the transfer material based on the calculated concealment rate, reads the following image parameters from the image data, performs threshold determination on the read image parameters, and adjusts the amount of white ink to be applied based on the determination result: A printing method characterized by: [Image parameters] The image parameters are one or more selected from the color ink deposition amount and color data measurable by a colorimeter. [Explanation of symbols]

[0147] 1. Information processing equipment 2. Image forming device 3. Control device 10 Printing System [Prior art documents] [Patent documents]

[0148] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-154516

Claims

1. A printing system having an ejection unit that ejects color inks and white ink onto a medium, and a control unit that controls the ejection unit, The printing system obtains image information and color information of the medium; The control unit adjusts the ejection amount of white ink based on the color information of the medium and the following image parameters in the image information: A printing system characterized by: [Image parameters] The image parameters are one or more selected from the ejection amount of color ink and color information measurable by a colorimeter.

2. A printing system having a discharge unit that discharges color inks and white ink onto a transfer substrate, and a control unit that controls the discharge unit, the color ink and the white ink ejected onto the transfer substrate are transferred onto a transfer receiving material, The printing system acquires image information and color information of the transfer material, The control unit adjusts the ejection amount of white ink based on the color information of the transfer material and the following image parameters in the image information: A printing system characterized by: [Image parameters] The image parameters are one or more selected from the ejection amount of color ink and color information measurable by a colorimeter.

3. A printing system having an ejection unit that ejects color inks and white ink onto a medium, and a control unit that controls the ejection unit, The printing system obtains image information, information about the color of the medium, and information about the density of the white ink; The control unit calculates a concealment rate of the medium based on information about the color of the medium and the density of the white ink, calculates the amount of white ink ejection required to conceal the medium based on the calculated concealment rate, reads the following image parameters from the image information, performs threshold determination on the read image parameters, and adjusts the amount of white ink ejection based on the determination result: A printing system characterized by: [Image parameters] The image parameters are one or more selected from the ejection amount of color ink and color information measurable by a colorimeter.

4. A printing system having a discharge unit that discharges color inks and white ink onto a transfer substrate, and a control unit that controls the discharge unit, the color ink and the white ink ejected onto the transfer substrate are transferred onto a transfer receiving material, The printing system obtains image information, color information of the transfer material, and density information of the white ink, The control unit calculates the concealment rate of the transfer material based on color information of the transfer material and the density of the white ink, calculates the ejection amount of the white ink necessary to conceal the transfer material based on the calculated concealment rate, reads the following image parameters from the image information, performs threshold judgment on the read image parameters, and adjusts the ejection amount of the white ink based on the judgment result: A printing system characterized by: [Image parameters] The image parameters are one or more selected from the ejection amount of color ink and color information measurable by a colorimeter.

5. The color information is spectral reflectance, spectral transmittance, brightness, saturation, or density.

5. The printing system according to claim 1, wherein the printing system is a printing system for printing a plurality of documents.

6. the image parameter is the ejection amount of the color ink; The control unit determines whether the ejection amount of the color ink is equal to or greater than a first threshold, and if the ejection amount of the color ink is equal to or greater than the first threshold, performs control to eject white ink at a predetermined lower limit of the ejection amount of white ink.

5. The printing system according to claim 1, wherein the printing system is a printing system for printing a plurality of documents.

7. the image parameter is the color information, The control unit determines whether the color information is equal to or less than a second threshold value, and if the color information is equal to or less than the second threshold value, performs control to eject white ink at the calculated ejection amount of the white ink.

5. The printing system according to claim 1, wherein the printing system is a printing system for printing a plurality of documents.

8. The control unit reads the image parameters for each predetermined area, performs threshold determination, and controls the amount of white ink to be ejected.

5. The printing system according to claim 1, wherein the printing system is a printing system for printing a plurality of documents.

9. The control unit calculates a total ink ejection amount, which is the sum of the ink ejection amounts of each ink, for each predetermined area, and when the difference in the total ink ejection amount between adjacent areas is equal to or greater than a predetermined threshold, performs gradation processing by adjusting the ejection amount of color ink so that the difference in the total ink ejection amount between adjacent areas becomes smaller than the predetermined threshold.

5. The printing system according to claim 1, wherein the printing system is a printing system for printing a plurality of documents.

10. the ejection unit is capable of ejecting transparent ink, The control unit calculates a total ink ejection amount, which is the sum of the ink ejection amounts of each ink, for each predetermined area, and if the difference in the total ink ejection amount between adjacent areas is equal to or greater than a predetermined threshold, adjusts the ejection amount of transparent ink so that the difference in the total ink ejection amount between adjacent areas becomes smaller than the predetermined threshold.

4. The printing system according to claim 1, wherein the printing system includes: a printer;

11. the white ink is used as a base after an image is formed on the medium, The control unit determines the image parameters and controls the discharge amount of white ink that forms the base.

4. The printing system according to claim 1, wherein the printing system includes: a printer;

12. the white ink is used as a base after the ink is transferred to the transfer material, The control unit determines the image parameters and controls the discharge amount of white ink that forms the base.

5. The printing system according to claim 2 or 4.

13. A printing device having a discharge unit that discharges color inks and white ink onto a medium, and a control unit that controls the discharge unit, The printing device obtains image information and color information of the medium; The control unit adjusts the ejection amount of white ink based on the color information of the medium and the following image parameters in the image information: A printing device characterized by: [Image parameters] The image parameters are one or more selected from the ejection amount of color ink and color information measurable by a colorimeter.

14. A printing device having a discharge unit that discharges color inks and white ink onto a transfer substrate, and a control unit that controls the discharge unit, the color ink and the white ink ejected onto the transfer substrate are transferred onto a transfer receiving material, The printing device acquires image information and color information of the transfer material, The control unit adjusts the ejection amount of white ink based on the color information of the transfer material and the following image parameters in the image information: A printing device characterized by: [Image parameters] The image parameters are one or more selected from the ejection amount of color ink and color information measurable by a colorimeter.

15. A printing method including a discharge step of discharging color inks and white ink onto a medium by a printing device, and a control step of controlling the discharge of the color inks and the white ink, The printing method includes obtaining image information and color information of the medium; The control step adjusts the ejection amount of white ink based on the color information of the medium and the following image parameters in the image information: A printing method characterized by: [Image parameters] The image parameters are one or more selected from the ejection amount of color ink and color information measurable by a colorimeter.

16. A printing method including a discharging step of discharging color inks and white ink onto a transfer substrate by a printing device, and a control step of controlling the discharge of the color inks and the white ink, the color ink and the white ink ejected onto the transfer substrate are transferred onto a transfer receiving material, The printing method includes obtaining image information and color information of the transfer material; The control step adjusts the discharge amount of white ink based on the color information of the transfer material and the following image parameters in the image information: A printing method characterized by: [Image parameters] The image parameters are one or more selected from the ejection amount of color ink and color information measurable by a colorimeter.

Images