Printing device, printing medium determination method and block selection method

Abstract

The present disclosure relates to a printing device, a print medium determination method, and a patch selection method, seeking improvements to control costs and appropriately determine the print medium. The printing device includes a printing unit that applies colorant to a print medium to perform printing, a color measurement unit that performs color measurement, a storage unit that stores patch data specifying the colors of a plurality of color patches, and a control unit. The control unit uses the patch data for one of the plurality of color patches stored in the storage unit to cause the printing unit to print the color patch on the print medium. The control unit then determines whether the type of the print medium on which the color patch is printed by the printing unit is a predetermined type based on a color measurement value obtained by the color measurement unit from the color measurement unit.

Description

Technical Field

[0001] The present invention relates to a printing device, a printing medium determination method and a block selection method. Background Art

[0002] An image forming apparatus is disclosed that detects the paper type of conveyed paper based on the detection result of a media sensor pre-installed on a paper conveyance path and a pre-installed paper type detection table (see Patent Document 1).

[0003] Furthermore, a configuration is disclosed in which a color measuring device is provided in a printer at a position downstream of a carriage holding a recording head in the conveying direction. The color measuring device measures a color measurement pattern recorded on a roll of paper to obtain a correction value for color calibration (see Patent Document 2).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-190707

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2009-220290 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] According to the above-mentioned document 1, in order to detect the paper type of the paper, a dedicated media sensor needs to be provided in the device, which increases the cost of the device. Therefore, there is a need for an improvement to appropriately determine the printing medium while minimizing the cost.

[0010] Solutions for solving problems

[0011] The printing device includes: a printing unit that prints by attaching colorant to a printing medium; a color measuring unit that performs color measurement; a storage unit that stores patch data for a plurality of color patches, the patch data specifying the colors of the color patches; and a control unit; the control unit uses the patch data of one of the plurality of color patches stored in the storage unit to cause the printing unit to print the color patch on the printing medium, and determines whether the type of the printing medium on which the color patch is printed by the printing unit is a predetermined type based on a color measurement value obtained by the color measuring unit when the color measuring unit measures the color patch printed by the printing unit.

[0012] A method for determining printing media includes: a block acquisition step of acquiring block data of a color block from a storage unit, the storage unit storing block data of the colors of a plurality of color blocks; a printing step of causing a printer to print the color block on the printing medium, the printer attaching color material to the printing medium using the block data of the color block to perform printing; and a determination step of determining whether the type of the printing medium on which the color block is printed by the printing unit is a predetermined type based on a color measurement value obtained by a color measurement unit when the color measurement unit measures the color of the color block printed by the printing unit.

[0013] The block selection method includes: an acquisition step of acquiring a reference value representing the color of a color block within a specified color space, and colorant data, the colorant data specifying a colorant usage amount for reproducing the reference value on a reference type of printing medium; a difference calculation step of calculating a difference between each color measurement value obtained when printing on each printing medium of a comparison type different from the reference type using the colorant data and the reference value; and a selection step of repeatedly executing the acquisition step and the difference calculation step while changing a combination of the color block and the reference type, and after repeatedly executing the acquisition step and the difference calculation step, selecting, for each type of printing medium serving as the reference type, a color block for determining the comparison type of printing medium based on the calculated difference. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a block diagram schematically showing the configuration of the device.

[0015] Figure 2 This is a diagram showing a specific example of the configuration mainly corresponding to the printing section.

[0016] Figure 3 is a flowchart illustrating a print color measurement process.

[0017] Figure 4 : is a flowchart showing the spot color DB registration process.

[0018] Figure 5A is a diagram showing an example of a spot color DB. Figure 5B 1 is a diagram showing an example of a spot color DB in which selection results of spot color patches for each media type are registered.

[0019] Figure 6 This is a diagram for explaining the processing of steps S200 to S230 using a specific example.

[0020] Figure 7 This is a diagram showing an example of difference table data.

[0021] Figure 8 It is shown in another form Figure 7 A plot of the difference table data.

[0022] Figure 9 This is a diagram for explaining the process of step S130 using a specific example.

[0023] Figure 10A 、 Figure 10B Each of them is a diagram showing an example of the image data generated in step S130.

[0024] Figure 11 : is a flowchart showing the color material data adjustment process.

[0025] Figure 12 This is a diagram showing an example of a spot color DB in which partial information is updated.

[0026] Figure 13 : is a flowchart showing the difference table data update process.

[0027] Description of Reference Numerals

[0028] 10 Printing device, 11 Control unit, 11a CPU, 11b ROM, 11c RAM, 12 Program, 12a Block selection processing unit, 12b Printing control unit, 12c Color measurement control unit, 12d Medium determination unit, 16 Transport unit, 17 Carriage, 18 Print head, 19 Color measurement unit, 20 Storage unit, 21 Printing unit, 30 Printing medium, 40 Spot color DB, 50 α, 50 β, 50 γ ICC profiles, 60 Difference table data, 73, 75 Spot color patches, 77 Evaluation patch. DETAILED DESCRIPTION

[0029] The following describes embodiments of the present invention with reference to the accompanying drawings. It should be noted that the drawings are merely illustrations of the present embodiments. Because the drawings are illustrations, their proportions and shapes may not always be accurate, may not be consistent with one another, or may contain portions omitted.

[0030] 1. Device composition:

[0031] Figure 1 Schematically shows the configuration of the printing apparatus 10 according to this embodiment.

[0032] The printing device 10 includes a control unit 11, a display unit 13, an operation reception unit 14, a communication interface 15, a transport unit 16, a carriage 17, a print head 18, a color measurement unit 19, a storage unit 20, and the like. "IF" stands for interface. The control unit 11 is composed of one or more integrated circuits (ICs) including a CPU 11a as a processor, ROM 11b, and RAM 11c, as well as other nonvolatile memory.

[0033] In the control unit 11, a processor, or CPU 11a, executes computations according to one or more programs 12 stored in a ROM 11b or other memory, using a RAM 11c or similar device as a workspace. This performs various functions, such as a block selection processing unit 12a, a print control unit 12b, a color measurement control unit 12c, and a media determination unit 12d. It should be noted that the processor is not limited to a single CPU; processing can be performed by multiple CPUs, hardware circuits such as ASICs, or a CPU and hardware circuits can collaborate to perform processing.

[0034] The display unit 13 is a device for displaying visual information and may be comprised of, for example, a liquid crystal display (LCD) or an organic EL display. The display unit 13 may also include a display and a driver circuit for driving the display. The operation reception unit 14 is a device for receiving user operations and may be implemented, for example, through physical buttons, a touch panel, a mouse, a keyboard, or the like. Of course, a touch panel may also be implemented as a function of the display unit 13.

[0035] The display unit 13 and the operation reception unit 14 may be integral components of the printing device 10 or may be peripheral devices externally connected to the printing device 10. The communication interface 15 is a general term for one or more interfaces used to connect the printing device 10 to the outside world via wired or wireless communication using a predetermined communication protocol, including known communication standards.

[0036] The transport unit 16 is a device for transporting the print medium and includes rollers, a motor for rotating the rollers, and the like. The print head 18 ejects ink onto the print medium using an inkjet method to perform printing. The color measurement unit 19 is a device for measuring the color of an object. The format of the color measurement value generated and output by the color measurement unit 19 as a color measurement result is, for example, the L format specified by the CIE (International Commission on Illumination). * a * b * L of color space * a * b * The value, or the combination of red (R), green (G), and blue (B) grayscale values ​​is the RGB value.

[0037] The carriage 17 is a mechanism that is driven by a carriage motor (not shown) and can reciprocate along a first direction. The first direction is also called the main scanning direction. Figure 2As shown, the print head 18 is mounted on the carriage 17. The structure including the conveying unit 16, the carriage 17, and the print head 18 is collectively referred to as the printing unit 21. The printing unit 21 can be any device that can attach a colorant to a printing medium to perform printing. The colorant is ink or toner. The printing unit 21 can adopt an inkjet method, and for example, an electrophotographic method or a thermal method can also be used to achieve printing. In addition, in this embodiment, the print head 18 is described as a serial print head that moves with the movement of the carriage 17, but a line print head that does not move during inkjet can also be used. The storage unit 20 can be implemented by a non-volatile memory, an HDD, or other storage devices. The storage unit 20 can be understood as a part of the control unit 11, for example, the RAM11c can be understood as a part of the storage unit 20.

[0038] Figure 1 The configuration of the printing device 10 shown may be realized by a single printer or by a plurality of devices connected in a communicable manner.

[0039] In other words, the printing device 10 may actually be a printing system 10. The printing system 10 includes, for example, an information processing device functioning as a control unit 11, a storage unit 20, and a printer including a printing unit 21 and a color measurement unit 19. This printing device 10 or printing system 10 implements the print medium determination method and block selection method of this embodiment.

[0040] Figure 2 2 is a specific example of a printing unit 21 as a part of the printing device 10. Figure 2 The above specific example is shown in the upper part of the drawing from a perspective perpendicular to the conveying direction Df of the print medium 30. Figure 2 The lower part inside shows a portion of the above-mentioned specific example from an upper perspective.

[0041] The conveying unit 16 includes a feed shaft 22 on the upstream side and a take-up shaft 25 on the downstream side. The upstream and downstream sides are simply referred to as upstream and downstream. A long print medium 30, wound in a roll around the feed shaft 22 and the take-up shaft 25, is stretched along a conveying direction Df. The print medium 30 is conveyed along the conveying direction Df. The print medium 30 may be paper or a material other than paper.

[0042] Figure 2In the upper example, the feed shaft 22 rotates clockwise, feeding the print medium 30 wound around it downstream. A front drive roller 23 is located downstream of the feed shaft 22, and a rear drive roller 24 is located upstream of the take-up shaft 25. The front drive roller 23 rotates clockwise, conveying the print medium 30 fed from the feed section 22 downstream. A nip roller 23n is provided for the front drive roller 23. The nip roller 23n abuts against the print medium 30, thereby sandwiching the print medium 30 between the nip roller 23n and the front drive roller 23.

[0043] The rear drive roller 24 rotates clockwise to convey the print medium 30, which has been conveyed downstream by the front drive roller 23, further downstream. A pinch roller 24n is provided on the rear drive roller 24. The pinch roller 24n abuts against the print medium 30, thereby sandwiching the print medium 30 between the pinch roller 24n and the rear drive roller 24.

[0044] The print head 18 is disposed between the front drive roller 23 and the rear drive roller 24 to eject ink from above toward the print medium 30. Figure 2 As can be seen, the print head 18 is mounted on the carriage 17. The print head 18 can eject multiple colors of ink, such as cyan (C), magenta (M), yellow (Y), and black (K). Although not shown, the print head 18 has nozzle rows corresponding to each CMYK ink. Each nozzle row corresponding to a color of ink is composed of multiple nozzles that eject that color of ink, that is, multiple nozzles with a fixed distance between nozzles (nozzle pitch) in the second direction D2.

[0045] The nozzles included in the printhead 18 are located on the surface of the printhead 18 facing the print medium 30. The printhead 18 determines whether to eject ink from the nozzles based on print data. Ink ejected from the nozzles is also called ink droplets or ink dots. The printhead 18 is also known as a printing head, inkjet head, or liquid ejection head.

[0046] The take-up shaft 25 rotates clockwise, and the printed print medium 30 conveyed by the rear driving roller 24 is wound around the take-up shaft 25 .

[0047] The motor (not shown) for appropriately rotating the feed shaft 22, the take-up shaft 25, and the rollers is a specific example of the conveying unit 16 for conveying the print medium 30. The number and arrangement of the rollers provided in the conveying path for conveying the print medium 30 are not limited to Figure 2 In addition, the ink color ejected by the print head 18 is not limited to the above-mentioned color. Of course, between the front drive roller 23 and the rear drive roller 24, a flat base plate or the like that supports the print medium 30 that receives the ink ejected by the print head 18 from below may also be provided.

[0048] The mark D1 represents the first direction. Figure 2In the example of FIG, between the front driving roller 23 and the rear driving roller 24, the conveying direction Df is parallel to the first direction D1. Figure 2 As shown in the lower part of the , the second direction D2 intersects the first direction D1. As described above, when the first direction D1 is referred to as the main scanning direction, the second direction D2 is referred to as the sub-scanning direction. The first direction D1 and the second direction D2 can be understood to be orthogonal. Figure 2 In the example shown in FIG, a long guide rail 26 is provided along the first direction D1 between the front drive roller 23 and the rear drive roller 24 and above the print medium 30. The carriage 17 can move along the guide rail 26. Of course, in order to stabilize the posture of the carriage 17, the member supporting the carriage 17 is not limited to the guide rail 26.

[0049] Furthermore, the carriage 17 is movable in the second direction D2. For example, a mechanism such as another guide rail is provided to reciprocate the carriage 17 and the guide rail 26 in the second direction D2. This movement of the carriage 17 in the first direction D1 or the second direction D2 is controlled by the control unit 11. In other words, the carriage 17, carrying the print head 18, is movable two-dimensionally relative to the surface of the print medium 30.

[0050] Movement of the carriage 17 in the second direction D2 corresponds to relative movement between the carriage 17 and the print medium 30 in the second direction D2. The action of the print head 18 ejecting ink as the carriage 17 moves in the first direction D1 is called a "main scan." A main scan is also called a "pass." Furthermore, relative movement between the carriage 17 and the print medium 30 in the second direction D2 is called a "sub-scan."

[0051] Figure 2 In the example shown, the color measurement unit 19 is provided downstream of the carriage 17. The color measurement unit 19 measures the color of the print medium 30 after printing by the print head 18. However, the color measurement unit 19 may be mounted on the carriage 17, for example, as long as it can measure the color of the print medium 30 after printing.

[0052] 2. Description of Spot Color DB

[0053] Figure 3 The print color measurement process involved in this embodiment is illustrated by a flowchart. This process includes a print medium determination method. This process can be implemented by the control unit 11 executing processing according to the program 12. In this embodiment, determining the print medium refers to determining whether the type of print medium 30 printed by the printing unit 21 is the type of print medium specified by the user. There are many different types of print media, such as plain paper, glossy paper, and other types of paper. The type of print medium specified by the user is referred to as the "specified type." The specified type is also called the predetermined type.

[0054] In step S120 of the print color measurement process, the control unit 11 retrieves a spot color patch corresponding to the specified type from the spot color database. "DB" stands for "database." The spot color database stores the spot color patches to be retrieved in step S120 for each print medium type. The spot color patches corresponding to the specified type are printed on the print medium 30 for color measurement in order to perform print medium determination (step S170).

[0055] Here, it is explained Figure 3 Before processing print color measurement, the spot color DB will be explained.

[0056] Figure 4 The spot color DB registration process executed by the control unit 11 according to the program 12 is shown by a flowchart. The spot color DB registration process includes a block selection method.

[0057] In step S200 , the block selection processing unit 12 a acquires one spot color from the spot color DB 40 . The spot color DB 40 is stored in the storage unit 20 in advance.

[0058] Figure 5A An example of a spot color DB 40 is shown. In the spot color DB 40, for each of the multiple spot color patches P1, P2, P3, P4, and P5, a mapping is defined between the color of the spot color patch, i.e., the spot color, and the CMYK values ​​for each type of print media. These CMYK values ​​are used to reproduce the spot color on the print media. The spot color patches P1, P2, P3, P4, and P5 each have a different spot color.

[0059] In the spot color DB 40, the spot color is defined by a predetermined color space. Specifically, by L * a * b * L of color space * a * b * The spot color is defined by the Lab value. The description of "*" is omitted as appropriate below. For example, the spot color block P1 is (L, a, b) = (56, 66, 36), which is red or a color close to red. In addition, the spot color block P2 is (L, a, b) = (47, -2, -43), which is blue or a color close to blue. Such Lab values ​​can become the "reference value" of the color of the spot color block. However, the color space defining the reference value can also be L * C * h * color space or other color spaces such as XYZ color space.

[0060] In the spot color DB 40, CMYK values ​​for reproducing spot colors on print media are specified for each of the multiple media types α, β, and γ. A CMYK value is a combination of grayscale values ​​representing the amount of ink for each CMYK color. Grayscale values ​​are represented, for example, by a 256-grayscale range from 0 to 255. CMYK values ​​correspond to "color material data." For example, the CMYK values ​​required to reproduce the Lab values ​​of the spot color patch P1 using print media of media type α are (C, M, Y, K) = (1, 84, 71, 0). Furthermore, the CMYK values ​​required to reproduce the Lab values ​​of the spot color patch P2 using print media of media type β are (C, M, Y, K) = (95, 61, 6, 0).

[0061] The CMYK values ​​specified in the spot color DB 40 can be calculated using a so-called ICC profile. Specifically, an ICC profile 50α is prepared in advance for media type α, which specifies the conversion relationship between CMYK values ​​and the color measurement values ​​(Lab values) of a patch reproduced using the CMYK values ​​on the print medium of media type α. Similarly, an ICC profile 50β for media type β and an ICC profile 50γ for media type γ are prepared in advance. The ICC profile 50β for media type β specifies the conversion relationship between CMYK values ​​and the color measurement values ​​(Lab values) of a patch reproduced using the CMYK values ​​on the print medium of media type β, while the ICC profile 50γ for media type γ specifies the conversion relationship between CMYK values ​​and the color measurement values ​​(Lab values) reproduced using the CMYK values ​​on the print medium of media type γ. The CMYK values ​​specified for each spot color patch and each media type in the spot color DB 40 are data calculated using the Lab values ​​of the spot color patch and these ICC profiles. The spot color DB 40 having the Lab value and the CMYK value as reference values ​​for each spot color patch can be said to define patch data for each color patch, and the patch data defines the color of the color patch.

[0062] In step S200 , the patch selection processing unit 12 a acquires the Lab value of one spot color, for example, the spot color patch P1 , from the spot color DB 40 .

[0063] In step S210, the patch selection processing unit 12a acquires CMYK values ​​corresponding to the spot color acquired in step S200 and one media type from the spot color DB 40. For example, the CMYK values ​​corresponding to the spot color patch P1 and the media type α are acquired.

[0064] The medium type corresponding to the CMYK values ​​obtained in step S210 is referred to as a “reference type” for convenience.

[0065] Such steps S200 and S210 correspond to an acquisition process, which acquires reference values ​​representing the colors of color patches using a predetermined color space and color material data for reproducing the reference values ​​on a reference type of printing medium.

[0066] In step S220 , the block selection processing unit 12 a calculates the Lab value for each medium type using the CMYK values ​​acquired in step S210 and the ICC profile for each medium type.

[0067] In step S230 , the block selection processing unit 12 a compares the Lab value of each medium type calculated in step S220 with the spot color acquired in step S200 , thereby calculating the color difference of each medium type.

[0068] Such steps S220 and S230 include a difference calculation process of calculating the difference between each color measurement value obtained when printing on each printing medium of a comparison type different from the reference type using the color material data obtained in the acquisition process and the reference value obtained in the acquisition process.

[0069] Figure 6 This is a diagram for explaining the processing of steps S200 to S230 using a specific example. Figure 6 In the example of , the spot color of the spot color block P1 is obtained in step S200, and the CMYK values ​​for reproducing the spot color block P1 on the printing medium of medium type α are obtained in step S210, where (C, M, Y, K) = (1, 84, 71, 0). That is, Figure 6 In the example, medium type α is the reference type. In step S220, the block selection processing unit 12a inputs (C, M, Y, K) = (1, 84, 71, 0) to the ICC profile 50α, ICC profile 50β, and ICC profile 50γ, respectively, and calculates the conversion results, i.e., Lab values, for each of the ICC profiles 50α, 50β, and 50γ. The ICC profiles 50α, 50β, and 50γ are stored in the storage unit 20.

[0070] Figure 6 In the example shown in FIG. 2 , the block selection processing unit 12a calculates (L, a, b) = (56, 66, 36) as the conversion result for the ICC profile 50α, (L, a, b) = (61, 55, 34) as the conversion result for the ICC profile 50β, and (L, a, b) = (52, 57, 37) as the conversion result for the ICC profile 50γ in step S220. The block selection processing unit 12a compares these Lab values, which are the conversion results, with the spot color of the spot color patch P1 in step S230 to calculate the color difference.

[0071] It should be noted that the Lab value obtained by converting the CMYK value used to reproduce the spot color patch P1 on the printing medium of the medium type α through the ICC profile 50α is the spot color of the spot color patch P1, so the relevant color difference is as follows: Figure 6 0 is shown.

[0072] according to Figure 6 In the example shown in Figure 5, the color difference between the Lab value obtained by converting the CMYK values ​​used to reproduce spot color patch P1 on print media of media type α using ICC profile 50β and the spot color of spot color patch P1 is 3.3. This means that if the CMYK values ​​used to reproduce spot color patch P1 on print media of media type α are used and the spot color is mistakenly printed on print media of media type β, the printed patch will have a color difference of 3.3 between it and the original color of spot color patch P1.

[0073] according to Figure 6 In the example shown in FIG5 , the color difference between the Lab value obtained by converting the CMYK values ​​used to reproduce spot color patch P1 on print medium of media type α using ICC profile 50γ and the spot color of spot color patch P1 is 3.4. This means that if the CMYK values ​​used to reproduce spot color patch P1 on print medium of media type α are used and the spot color is mistakenly printed on print medium of media type γ, the printed patch will have a color difference of 3.4 between it and the original color of spot color patch P1.

[0074] In step S240, the block selection processing unit 12a determines whether the CMYK values ​​for each media type corresponding to the spot color acquired in step S200 have been completely acquired from the spot color DB 40 in step S210. If any CMYK values ​​have not been acquired, the process returns to step S210 from the "No" determination in step S240, acquires CMYK values ​​corresponding to another media type, and executes steps S220 and S230. On the other hand, if the CMYK values ​​for each media type corresponding to the spot color acquired in step S200 have been completely acquired from the spot color DB 40 in step S210, the process returns to step S250 from the "Yes" determination in step S240.

[0075] In step S250, the block selection processing unit 12a determines whether all the spot colors of the spot color block have been acquired from the spot color DB 40 in step S200. If any spot colors have not been acquired, the process returns to step S200 from the "No" determination in step S250, acquires another spot color, and executes step S210 and subsequent steps. On the other hand, if all the spot colors of the spot color block have been acquired from the spot color DB 40 in step S200, the process returns to step S260 from the "Yes" determination in step S250.

[0076] As a result of the determination in steps S240 and S250 , the combination of the color block and the reference type is changed, and the acquisition process (steps S200 and S210 ) and the difference calculation process (steps S220 and S230 ) are repeated.

[0077] When the determination in step S250 is “YES”, the block selection processing unit 12 a calculates the color difference for each medium type for all CMYK values ​​specified in the spot color DB 40 .

[0078] In step S260 , the block selection processing unit 12 a generates difference table data 60 that represents the color difference for each medium type calculated in step S230 in a table format, and stores the difference table data 60 in the storage unit 20 .

[0079] Figure 7 An example of the difference table data 60 is shown. Figure 7 As shown, the difference table data 60 is composed of difference tables 60P1, 60P2, 60P3, 60P4, and 60P5 that summarize the color differences for each of the spot color patches P1, P2, P3, P4, and P5. Figure 7 The difference table represents the color difference between the Lab value when the corresponding spot color block is printed on the reference type and the Lab value when it is printed on the contrast type. For example, the difference table 60P1 corresponding to the spot color block P1 represents the color difference between the Lab value when the spot color block P1 is printed on the reference type and the Lab value when it is printed on the contrast type. It should be noted that the "Lab value when printing" refers to the color measurement value that can be obtained by performing color measurement after printing. In step S220, the ICC profile is used to calculate such color measurement value. The contrast type refers to the medium type corresponding to each Lab value calculated in step S220. It can be understood that the reference type is included in the contrast type, or it can be understood that the reference type is not included in the contrast type. For example, the difference table 60P1 stipulates a color difference of 3.3 for the relationship between reference type = medium type α and contrast type = medium type β, and stipulates a color difference of 3.4 for the relationship between reference type = medium type α and contrast type = medium type γ. These color differences are Figure 6 Color difference shown.

[0080] Figure 8 The difference table data 60 is shown in other representation forms. Figure 8 In FIG. 6 , the difference table data 60 is composed of difference tables 60α, 60β, and 60γ that summarize the color differences for each reference type (medium types α, β, and γ). Figure 7 The difference table data 60 shown is Figure 8The difference table data 60 shown is only different in the form of expression, and the content is the same. For example, the difference table 60α is a table formed by extracting the color difference corresponding to the reference type = medium type α from the difference tables 60P1, 60P2, 60P3, 60P4, and 60P5. In this embodiment, Figure 7 、 Figure 8 The difference table data 60 in the two forms shown are not necessarily required, as long as one of them is present. Figure 7 、 Figure 8 The difference table data 60 is shown in both figures.

[0081] In step S270, the block selection processing unit 12a selects a spot color block for each media type α, β, and γ with reference to the difference table data 60, and registers the selected result in the spot color DB 40. Step S270 is equivalent to a selection process, and based on the difference calculated by steps S200 to S250, for each type of printing medium as a reference type, a color block for distinguishing from the printing medium of the comparison type is selected. The block selection processing unit 12a selects, for example, a block with a larger average color difference. The so-called average color difference here refers to the average value of the color difference of each comparison type relative to the reference type. For example, with respect to the spot color block P1 of the difference table 60α, the color difference between the reference type α and the comparison type β is 3.3, and the color difference between the reference type α and the comparison type γ is 3.4, and the average value is 3.35. According to Figure 8 According to the difference table 60α, the spot color patch P1 has the largest average color difference from the contrast type. Specifically, based on the CMYK values ​​used to print spot color patch P1 on media type α, the Lab values ​​obtained when mistakenly printing on media type β or media type γ differ significantly from the spot color of spot color patch P1. Therefore, the patch selection processing unit 12a selects spot color patch P1 from the spot color patches P1, P2, P3, P4, and P5 for media type α.

[0082] Furthermore, according to difference table 60β, the spot color patch P5 has the largest average color difference from the contrast type. That is, based on the CMYK values ​​used to print spot color patch P5 on media type β, there is a significant color difference between the Lab values ​​obtained when mistakenly printing on media type α or media type γ and the spot color of spot color patch P5. Therefore, the patch selection processing unit 12a selects spot color patch P5 for media type β. Similarly, based on difference table 60γ, the spot color patch P1 has the largest average color difference from the contrast type. That is, based on the CMYK values ​​used to print spot color patch P1 on media type γ, there is a significant color difference between the Lab values ​​obtained when mistakenly printing on media type α or media type β and the spot color of spot color patch P1. Therefore, the patch selection processing unit 12a selects spot color patch P1 for media type γ.

[0083] Figure 5BThe spot color DB 40 in which the selection results of the blocks for each media type are registered is described in FIG. Figure 5B , in the spot color DB 40, the spot color patch P1 is selected for the corresponding medium type α. Figure 5B , it is registered that the spot color patch P5 is selected for the media type β, and the spot color patch P1 is selected for the media type γ.

[0084] As above, Figure 4 The spot color DB registration process ends.

[0085] 3. Print color measurement processing:

[0086] Next, we will explain the following, assuming that the spot color DB registration process has been executed. Figure 3 Print color measurement processing.

[0087] In step S100, the print control unit 12b acquires an image to be printed. Specifically, the print control unit 12b inputs image data representing the image, which is specified by the user through an operation of the operation reception unit 14, from a predetermined storage source. The image data acquired in step S100 is, for example, bitmap data representing the color of each pixel using RGB values.

[0088] In step S110, the print control unit 12b obtains the printing conditions for the image. These printing conditions are also obtained as information specified by the user through an operation of the operation reception unit 14. Alternatively, the printing conditions may be information pre-set in association with the image data obtained in step S100. The printing conditions include information such as the print medium type, the print medium size associated with a single print, the number of passes, and the subscan amount. The print medium type in the printing conditions is a specified type. The print medium size is expressed as the media width x the media length. Figure 2 In the example of FIG, the medium length is the length in the first direction D1, and the medium width is the length in the second direction D2. In this embodiment, one printing is also referred to as one frame printing, and the printing medium size is also referred to as the frame size.

[0089] The number of passes is the number of passes required to print one frame, and the sub-scanning distance is the distance of sub-scanning performed between the passes required to print one frame.

[0090] It should be noted that the order of steps S100 and S110 may also be different. Figure 3 As shown, steps S100 and S110 may be performed substantially simultaneously, or may be performed in accordance with Figure 3 The processing is performed in the reverse order of the shown order.

[0091] In step S120, the print control unit 12b obtains a spot color patch corresponding to the designated type from the spot color DB 40 stored in the storage unit 20. Figure 5B In this example, if the designated type is media type α, the print control unit 12b acquires information about the spot color patch P1. Furthermore, if the designated type is media type β, the print control unit 12b acquires information about the spot color patch P5. If the designated type is media type γ, the print control unit 12b acquires information about the spot color patch P1. Step S120 corresponds to a patch acquisition step, in which patch data for one color patch is acquired from the storage unit 20.

[0092] In step S130, the print control unit 12b generates image data to which the spot color patches acquired in step S120 are added. Specifically, the print control unit 12b first arranges the image data according to the frame size. Specifically, the print control unit 12b arranges the image data acquired in step S100 according to the frame size under the printing conditions acquired in step S110, thereby generating image data for printing one frame. The print control unit 12b then composites the spot color patches at predetermined locations within the frame-sized image data.

[0093] Figure 9 This is a diagram for explaining the process of step S130 using a specific example. Figure 9 The mark 70 in the upper part of the image data represents the image data acquired in step S100. The image data 70 represents a star-shaped image 71 drawn in a certain color. The content of the image 71 is arbitrarily determined by the user. Figure 9 In the example of , the image data 70 is image data having a size of 13 inches in length and 9 inches in width. Figure 9 The corresponding relationship between the image data and the directions D1 and D2 is also shown in FIG.

[0094] The content of the printing conditions obtained in step S110 is various. Figure 9 , assuming that the frame size = medium width 13 inches × medium length 36 inches. At this time, in step S130, the printing control unit 12b copies the image data 70 and continuously arranges four corresponding to the first direction D1, thereby generating the following Figure 9 The middle portion shows image data 72 for printing one frame. In step S130, the print control unit 12b may also enlarge or reduce the image data 70 as needed.

[0095] Then, in step S130, the print control unit 12b synthesizes the spot color patch 73 at a predetermined position in the image data 72, thereby generating a Figure 9The image data 74 shown below. The "predetermined position" here refers to, for example, a predetermined position for the color measurement unit 19 to perform color measurement on the spot color patch, and is a position as far downstream as possible within the image data 72. Furthermore, the print control unit 12b synthesizes a spot color patch 73 at a position within the image data 72 that does not overlap with the image 71. Here, assuming that the designated type = media type α, the spot color patch 73 is the spot color patch P1. Specifically, the print control unit 12b retrieves the CMYK values ​​corresponding to the media type α of the spot color patch P1 from the spot color DB 40 and synthesizes the spot color patch 73, an image area formed by a collection of pixels having the retrieved CMYK values, within the image data 72.

[0096] In step S140, the print control unit 12b performs necessary image processing on the image data 74 generated in step S130, thereby generating print data for the printer 21 to print. For example, the print control unit 12b performs color conversion processing on the image data 74. Specifically, the RGB values ​​of each pixel constituting the image data 74 are converted into CMYK values ​​with reference to a pre-generated color conversion LUT. LUT stands for lookup table. A color conversion LUT is a table that specifies the correspondence between RGB values ​​and CMYK values. It should be noted that this color conversion processing is not required for the area of ​​the image data 74 corresponding to the spot color patch 73.

[0097] The print control unit 12b then performs halftoning on the image data 74. Through color conversion, the image data 74 is converted to a state where each pixel has CMYK values. Halftoning converts the image data 74 into print data that specifies whether ink should be ejected (dot-on) or not (dot-off) for each pixel and each CMYK color. Of course, the dot-on information in the print data may also specify which of various dot sizes should be ejected, such as large, medium, or small. Halftoning can be performed using, for example, a dithering method or an error diffusion method.

[0098] In step S150, the print control unit 12b causes the print unit 21 to print one frame based on the print data and print conditions. Specifically, the print control unit 12b controls the movement of the carriage 17 in the first direction D1 and the second direction D2 according to the number of passes and the amount of sub-scanning specified in the print conditions, while simultaneously causing the print head 18 to eject ink according to the print data. During each pass, the print head 18 ejects or does not eject each CMYK color ink from each nozzle based on the dot-on / dot-off information specified for each pixel in the print data. As a result, the image 71 represented by the image data 74 and the spot color patches 73 are printed within the size of one frame on the print medium 30. Step S150 corresponds to the printing process, causing the print unit 21 to print the color patches on the print medium 30. During the one-frame printing period in step S150, the transport unit 16 does not transport the print medium 30. That is, in step S150, the passes and sub-scanning are performed on the stationary print medium 30.

[0099] In step S160, the color measurement control unit 12c controls the color measurement unit 19 to perform color measurement on the spot color patch printed on the print medium 30. Figure 9 In the example shown in FIG. 1 , the color measurement unit 19 performs color measurement on the spot color patch 73 printed on the print medium 30 and outputs the color measurement value obtained by the color measurement to the control unit 11. Of course, after step S150 and before step S160, the transport unit 16 transports the print medium 30 a necessary distance to facilitate the color measurement unit 19 to perform color measurement on the spot color patch 73.

[0100] In step S170, the media determination unit 12d determines whether the type of print medium 30 on which the spot color patch was printed by the printing unit 21 is the designated type based on the color measurement values ​​obtained from the color measurement of the spot color patch in step S160. Steps S170 and S180 constitute the determination process. At this point, the media determination unit 12d calculates the color difference between the color measurement values ​​of the spot color patch and the spot color corresponding to the designated type. Assuming that the designated type = media type α, as described above, in step S120, the information on the spot color patch P1 is obtained from the spot color DB 40. Therefore, the media determination unit 12d can compare the Lab values ​​(56, 66, 36) representing the color of the spot color patch P1 with the color measurement values ​​of the spot color patch obtained in step S160 to calculate the color difference.

[0101] Then, the medium determination unit 12d compares the color difference calculated in this manner with a predetermined threshold value related to color difference to determine whether the color difference is less than the threshold value or the color difference is greater than or equal to the threshold value. Figure 8 , for example, a suitable threshold is about 2.0. This threshold can be set arbitrarily by the user.

[0102] In step S180, the media determination unit 12d branches the process according to the determination result of step S170. If the color difference is less than the threshold value, the media determination unit 12d determines that the type of the print medium 30 on which the spot color patch is printed by the printing unit 21 is the specified type, that is, the print medium 30 is appropriate (step S180: Yes), and ends the process. Figure 3 On the other hand, when the color difference ≥ the threshold value, the medium determination unit 12d determines that the type of the print medium 30 is not the designated type, that is, the print medium 30 is unsuitable (step S180: No), and proceeds to step S190.

[0103] Figure 3 Although not shown in the figure, after the control unit 11 determines that the print color measurement process is completed based on "Yes" in step S180, it can continue to control the printing unit 21 to print the next frame.

[0104] In step S190, the control unit 11 performs medium error processing and ends Figure 3 The medium error processing is a process of stopping printing related actions, for example. That is, since the type of printing medium 30 different from the type expected by the user is set in the current printing unit 21, the control unit 11 stops driving the printing unit 21 and ends the process. Figure 3 Flowchart. Thus, it is possible to prevent the printing medium 30 and ink from being wasted further. In addition, as one of the media error processing, the control unit 11 may also display a warning screen on the display unit 13 to inform the user that the printing medium 30 is not suitable.

[0105] Figure 9 In the example of , the image 71 in the image data 74 and the spot color block 73 are expressed in the same color. That is, Figure 3 In the print color measurement process, the image acquired in step S100 and the spot color patch added in step S130 can also be printed in the same color. In this case, the print control unit 12b can generate image data 74 in step S130, including the image 71, in which each pixel color is expressed using the same CMYK values ​​as the spot color patch acquired from the spot color DB 40 in step S120 according to the specified type, and the spot color patch 73. In this way, by printing the image 71 and the spot color patch 73 in the same color on the print medium 30, the control unit 11, which obtains the color measurement value of the patch 73 through the color measurement in step S160, can not only perform the determinations in steps S170 and S180 but also determine whether the color of the image 71 in the print result is appropriate. Based on the color measurement value of the spot color patch 73, the control unit 11 determines whether the color of the image 71 in the print result is appropriate and can notify the user of the determination result or, if necessary, perform color calibration of the image 71.

[0106] 4. Other examples of block printing:

[0107] Figure 10A An example of the image data 74 generated in step S130 is shown, which is different from Figure 9 Example shown. Figure 10A The image data 74 shown includes a plurality of spot color patches 73 and 75. That is, the print control unit 12b can print the plurality of spot color patches together with the image 71 on the print medium 30.

[0108] illustrate Figure 10A , it is assumed that the designated type = medium type β. In addition, it is assumed that in the spot color DB 40 described so far, spot color patches P1 to P4 are defined, and spot color patch P5 is not defined. Therefore, Figure 8 In the difference table data 60 shown, the color difference information corresponding to the spot color patch P5 is not present in the difference tables 60α, 60β, and 60γ. Figure 4 In step S270 of the process (see step S170), the patch selection processing unit 12a selects spot color patch P1 and spot color patch P4 for media type β and registers them in the spot color DB 40. Specifically, according to the difference table 60β, if spot color patch P5 does not exist, then there is also no spot color patch with a sufficiently large color difference from either media type α or γ. A sufficiently large color difference means that the difference is greater than or equal to the threshold used for the determination in step S170. Therefore, the patch selection processing unit 12a selects spot color patch P1 as the spot color patch for comparing media type β with media type α, and selects spot color patch P4 as the spot color patch for comparing media type β with media type γ.

[0109] In this case, when the specified type = medium type β, Figure 3 In step S120, the print control unit 12b retrieves information about the spot color patch P1 and the spot color patch P4 from the spot color DB 40. Then, in step S130, the print control unit 12b generates image data 74 by adding a spot color patch 73, in which each pixel has CMYK values ​​corresponding to the media type β of the spot color patch P1, and a spot color patch 75, in which each pixel has CMYK values ​​corresponding to the media type β of the spot color patch P4. As a result, the spot color patches 73 and 75 are printed on the print medium 30 along with the image 71. The media determination unit 12d uses the color measurement values ​​of the spot color patches 73 and 75 to make the determinations in steps S170 and S180. At this time, the medium determination unit 12 d compares the color difference between the color measurement value of the spot color patch 73 and the Lab value of the spot color patch P1 specified in the spot color DB 40, and the color difference between the color measurement value of the spot color patch 75 and the Lab value of the spot color patch P4 specified in the spot color DB 40 with the threshold value. If any color difference is greater than the threshold value, the judgment is "No" in step S180.

[0110] Figure 10B An example of the image data 74 generated in step S130 is shown, which is different from Figure 9 、 Figure 10AThe color of the image to be printed on the print medium 30 is of course different from the color of the spot color patch printed together with the image. Figure 10B In the example shown in FIG. 7 , image data 74 includes an image 76 and a spot color patch 73 of different colors. In this case, print control unit 12b may cause image data 74 to include both image 76 and spot color patch 73, along with an evaluation patch 77 of the same color as image 76. As a result, spot color patch 73 and evaluation patch 77 are printed onto print medium 30 along with image 76. The media determination unit 12d then uses the color measurement value of spot color patch 73 to perform the determinations in steps S170 and S180. Furthermore, control unit 11 can determine whether the color of image 76 in the printed result is appropriate based on the color measurement value of evaluation patch 77.

[0111] 5. Summary:

[0112] According to this embodiment, the printing device 10 includes a printing unit 21 that prints by attaching colorant to a print medium, a color measurement unit 19 that performs color measurement, a storage unit 20 that stores patch data specifying the colors of a plurality of color patches, and a control unit 11. The control unit 11 uses the patch data for one of the plurality of color patches stored in the storage unit 20 to cause the printing unit 21 to print the color patch on the print medium. The control unit 11 then determines whether the type of the print medium on which the color patch printed by the printing unit 21 is a predetermined type based on the color measurement value obtained by the color measurement unit 19 when measuring the color of the color patch printed by the printing unit 21.

[0113] With this configuration, a dedicated media sensor for detecting paper type is not required. Instead, the color measurement unit 19, which measures the color of images or patches, can be used to determine whether the print medium used by the printing unit 21 is the specified type. This allows for cost reduction and identification of the print medium. Furthermore, using the color measurement values ​​of the color patches measured by the color measurement unit 19, it is possible to not only identify the print medium but also evaluate and determine the color of the printed result.

[0114] Furthermore, according to the present embodiment, the patch data stored in the storage unit 20 includes reference values ​​representing patch colors in a predetermined color space, and colorant data for each print medium type, which specifies the amount of colorant used to reproduce the reference values ​​on the print medium.

[0115] According to the above configuration, the control unit 11 can use the color material data stored in the storage unit 20 for reproducing the reference value of the one color patch to enable the printing unit 21 to print the color patch on the printing medium, and determine whether it is the specified type based on the color measurement value and the reference value of the color patch.

[0116] Furthermore, according to this embodiment, the control unit 11 causes the printing unit 21 to print the color patch using the color material data corresponding to the predetermined type in the block data of the one color patch, and performs the determination based on the difference between the color measurement value and the reference value in the block data of the one color patch.

[0117] According to the above configuration, the printing unit 21 evaluates the difference between the color measurement value and the reference value, which should theoretically match when a specified type of printing medium is used, thereby accurately determining whether the printing medium is of the specified type.

[0118] Furthermore, according to this embodiment, the storage unit 20 stores the difference between each color measurement value and the reference value obtained when printing on each type of printing medium of another type using the color material data for reproducing the reference value on the predetermined type of printing medium, in the difference table data 60 representing each of the plurality of color patches. The control unit 11 then selects the one color patch from the plurality of color patches with reference to the difference table data 60.

[0119] According to the above configuration, the control unit 11 can select the color patch that is most suitable for determining whether it is of the specified type from among the plurality of color patches.

[0120] In addition to the printing device 10, this embodiment also discloses various inventions such as methods and programs. The print medium determination method includes: a patch acquisition step of acquiring patch data for a single color patch from a storage unit 20 storing patch data of a predetermined color patch color for a plurality of color patches; a printing step of causing a printing unit 21, which prints by attaching color material to the print medium, to print the color patch on the print medium using the patch data; and a determination step of determining whether the type of print medium on which the color patch has been printed by the printing unit 21 is a predetermined type based on a color measurement value obtained by a color measurement unit 19 measuring the color of the color patch printed by the printing unit 21.

[0121] Furthermore, according to this embodiment, the patch selection method includes: an acquisition step of acquiring reference values ​​representing the colors of the color patches in a predetermined color space and colorant data defining the amount of colorant required to reproduce the reference values ​​on a reference type of print medium; and a difference calculation step of calculating the difference between each color measurement value obtained when printing on each type of print medium of a comparative type different from the reference type using the colorant data and the reference value. The acquisition step and the difference calculation step are then repeated, with the combination of the color patches and the reference type being varied. The patch selection method further includes a selection step of selecting, based on the calculated differences after the acquisition and difference calculation steps are repeated, a color patch for distinguishing the reference type of print medium from the comparative type of print medium.

[0122] According to the block selection method, for each type of print medium, the color block that is most suitable for comparison with other types of print media can be selected. Therefore, by using the color blocks selected in this way, the print medium can be accurately judged.

[0123] 6. Modifications:

[0124] Modifications included in this embodiment will be further described.

[0125] First variant:

[0126] The control unit 11 may issue a predetermined warning to the user when a color measurement value obtained when printing on another type of printing medium using the color material data corresponding to the predetermined type in the block data of the one color patch differs from a reference value of the block data of the one color patch within a predetermined difference.

[0127] according to Figure 7 、 Figure 8 In the example of the difference table data 60 shown in FIG. 1 , for media types α, β, and γ, a spot color patch having an average color difference of more than 3.0 from the comparison type can be selected. Figure 4 The results of the spot color DB registration process up to step S260 do not necessarily indicate that a spot color patch with a sufficiently high color difference from the contrast type has been selected for media types α, β, and γ. For example, suppose that the average color difference of all spot color patches for media type β with respect to the contrast type media types α and γ is less than the specified difference of "2.0." In this case, the control unit 11 needs to select and register a spot color patch for media type β with the largest possible average color difference from the contrast type. In step S270, the control unit 11 selects a spot color patch P3 for media type β with an average color difference of, for example, "1.8" from the contrast type media types α and γ.

[0128] at this time, Figure 3 In the print color measurement process, assuming the designated type = media type β, the control unit 11 issues a predetermined warning to the user when acquiring information about the spot color patch P3 from the spot color DB 40 based on the designated type in step S120. This warning indicates that the accuracy of determining whether the designated type is the spot color patch P3 printed on the print medium 30 due to the designated type being media type β is low. Furthermore, simultaneously with this warning, the control unit 11 may also stop driving the print unit 21, similar to step S190. Upon recognizing the low accuracy of the spot color patch, the user can instruct the control unit 11 to continue or cancel the processing after step S130. This configuration protects the user from the adverse effects of continuing printing without realizing the low accuracy of the spot color patch.

[0129] Second variant:

[0130] Figure 5A 、 Figure 5B The CMYK values ​​corresponding to the spot color patches and media types in the spot color DB 40 are calculated based on the Lab values ​​of the spot color patches and the ICC profile for each media type. The control unit 11 can also adjust the CMYK values ​​in the spot color DB 40 based on actual printing and color measurement. Specifically, the control unit 11 selects color material data to be updated from the color material data stored in the storage unit 20, and uses the selected color material data to cause the printing unit 21 to print a color patch corresponding to the selected color material data on the print medium. The control unit 11 then adjusts the selected color material data based on a comparison of the color measurement values ​​obtained by the color measurement unit 19 on the printed color patch with the reference values ​​of the color patch corresponding to the selected color material data. The selected color material data is then updated in the storage unit 20 using the adjusted color material data.

[0131] Figure 11 The flowchart shows the color material data adjustment process for adjusting the CMYK values ​​of the spot color DB 40. The color material data adjustment process will be described by taking the case of adjusting the CMYK values ​​corresponding to the medium type α as an example.

[0132] In step S300, the control unit 11 obtains the CMYK values ​​of the spot color patches P1, P2, P3, P4, and P5 corresponding to a medium type, namely, medium type α, from the current spot color DB 40. Step S300 corresponds to the process of selecting the color material data to be updated. When the control unit 11 performs the color material data adjustment process for medium type α for the first time, it can obtain the CMYK values ​​as the default values ​​in step S300. The default values ​​of the CMYK values ​​are values ​​calculated based on the Lab values ​​of the spot color patches and the ICC profile of each medium type, which are Figure 5A 、 Figure 5B The CMYK values ​​of the spot color DB40 are shown.

[0133] In step S310, a color table is generated based on the CMYK values ​​of each spot color patch acquired in step S300. A color table is image data representing multiple color patches of varying colors. The control unit 11 generates a color patch containing the CMYK values ​​of the spot color patch acquired in step S300, and multiple color patches corresponding to multiple CMYK values ​​obtained by varying the grayscale values ​​of at least one CMYK ink color from this CMYK value. The control unit 11 repeatedly performs this process for each spot color patch, adding color patches with slightly different CMYK values ​​from the spot color patch, thereby generating a color table.

[0134] In step S320 , the control unit 11 performs necessary image processing on the color table generated in step S310 , and generates print data for printing the color table.

[0135] In step S330, the control unit 11 causes the printing unit 21 to print the color table onto a print medium of the corresponding media type based on the print data generated in step S320. In this case, the corresponding media type is, of course, media type α. When the user instructs the printing device 10 to perform color material data adjustment processing for media type α, the print medium 30 of media type α is placed in the printing unit 21.

[0136] In step S340 , the control unit 11 causes the color measurement unit 19 to perform color measurement on the color chart printed on the print medium 30 of the medium type α in step S330 , thereby acquiring color measurement values ​​of each color patch of the color chart.

[0137] In step S350, the control unit 11 compares the color measurement values ​​of each color patch obtained through the color measurement in step S340 with the Lab values ​​of each spot color patch specified in the spot color DB 40 to calculate new CMYK values ​​corresponding to the Lab values ​​of each spot color patch. Step S350 is a process for adjusting the CMYK values. Step S350 can employ various methods, including well-known ones. For example, the control unit 11 may map the color measurement values ​​of each color patch to Lab space and, based on the positional relationship between the Lab values ​​of each spot color patch and the Lab values ​​of each color patch, calculate CMYK values ​​corresponding to the Lab values ​​of the spot color patch with higher precision through interpolation or other means. The CMYK values ​​calculated in this manner are the new CMYK values ​​corresponding to the Lab values ​​of the spot color patch.

[0138] In step S360, the control unit 11 uses the new CMYK values ​​calculated for each spot color patch in step S350 to update the CMYK values ​​of each spot color patch currently specified for media type α in the spot color DB 40. As a result, the spot color DB 40 specifies CMYK values ​​that accurately reproduce each spot color on print media of media type α.

[0139] Above, the color material data adjustment process related to the medium type α is completed once. Figure 11 As shown by the dotted arrow, the control unit 11 may also repeatedly execute the color material data adjustment process related to the medium type α. By repeating this process, the spot color reproduction accuracy of the CMYK values ​​specified in the spot color DB 40 can be further improved.

[0140] Figure 12 The spot color DB 40 is shown with some information updated after the color material data adjustment process related to the medium type α. Figure 12 The spot color DB40 and Figure 5A 、 Figure 5BWhen the spot color DB 40 is compared with the spot color DB 40, the CMYK values ​​of the spot color patches P1, P2, P3, P4, and P5 corresponding to the medium type α, which are surrounded by the dotted frame, are updated. Of course, the control unit 11 can perform the color material data adjustment process for the medium type β and the color material data adjustment process for the medium type γ in the same manner as the color material data adjustment process for the medium type α.

[0141] Furthermore, the control unit 11 may refer to the spot color DB 40 whose CMYK values ​​have been updated in this manner to perform Figure 4 The spot color DB registration process performed with reference to the updated spot color DB 40 results in a different color difference value calculated in step S230 than in the spot color DB registration process performed with reference to the spot color DB 40 before the update. Therefore, the spot color patch selected for each media type in step S270 may differ from the spot color patch previously selected in the spot color DB registration process. As a result, the registration of the spot color patch for each media type in the spot color DB 40 is updated.

[0142] Third variant:

[0143] Figure 3 In the print color measurement process, if the judgment in step S180 is "No", the control unit 11 may also execute Figure 13 The process shown is one of the medium error processes (step S190). Figure 13 The difference table data update process is shown by a flowchart.

[0144] In step S400, the control unit 11 displays an error message indicating that the printing medium 30 is not suitable on a warning screen and requests an input of a usage type, which is the type of printing medium currently set in the printing unit 21 for printing in step S150.

[0145] In step S410, the control unit 11 accepts input of a usage type from the user. The user, upon seeing the warning screen in step S400, realizes that the specified type differs from the usage type and needs to enter the usage type. The user checks the print unit 21 to identify the usage type and operates the operation accepting unit 14 to enter the usage type.

[0146] The control unit 11, which has recognized the usage type based on the user input, updates the difference table data 60 (step S420) based on the usage type and the color difference calculated in the judgment of step S170, that is, the color difference between the spot color corresponding to the specified type and the color measurement value of the spot color patch obtained by the color measurement of step S160. For example, assuming that the specified type = medium type α, the control unit 11 prints the spot color patch P1 corresponding to medium type α on the print medium 30 in step S150, the color difference calculated in step S170 is "2.8", and the judgment in step S180 is "No". In addition, the usage type accepted in step S410 is set to medium type γ. In this case, in step S420, the control unit 11 Figure 7 、 Figure 8 The color difference “3.4” specified for the relationship of the spot color patch P1, the reference type=media type α, and the comparison type=media type γ in the difference table data 60 is updated to a color difference “2.8”.

[0147] In this way, the accuracy of the difference table data 60 can be improved by updating the difference table data 60 based on the color difference calculated in step S170 based on the actual color measurement result of the spot color patch and the information of the usage type. After the control unit 11 updates the difference table data 60 in step S420, it can execute Figure 4 That is, the spot color patch selection for each media type and the registration in the spot color DB 40 are re-performed with reference to the difference table data 60 whose accuracy has been improved due to the update. As a result, a spot color patch suitable for distinguishing from other types of printing media can be more accurately selected for each media type.

[0148] Other examples:

[0149] The relative movement of the carriage 17 and the print medium 30 in the second direction D2, i.e., the secondary scan, may also be achieved by conveying the print medium 30 instead of moving the carriage 17 along the second direction D2. That is, the conveying direction Df in which the conveying unit 16 conveys the print medium 30 may not be the same as Figure 2 The direction shown is not parallel to the first direction D1, but parallel to the second direction D2. At this time, between each pass, the conveying unit 16 can convey the printing medium 30 according to the sub-scanning amount.

[0150] The print medium 30 is not limited to a long medium such as roll paper, and may also be a sheet of paper that is cut in advance in units of pages.

Claims

1. A printing device, characterized in that: include: A printing unit that attaches colorant to a printing medium to perform printing; Color measurement department, which performs color measurement; a storage unit storing block data for a plurality of color blocks, wherein the block data specifies the color of the color blocks; as well as Control Department, The control unit uses the block data of one of the plurality of color blocks stored in the storage unit to cause the printing unit to print the color block on the printing medium. The control unit determines whether the type of the printing medium on which the color patch is printed by the printing unit is a predetermined type based on a color measurement value obtained by the color measurement unit when measuring the color of the color patch printed by the printing unit. The patch data stored in the storage unit includes a reference value representing the color of the color patch in a predetermined color space, and colorant data for each type of printing medium, the colorant data specifying the amount of the colorant used to reproduce the reference value on the printing medium. The control unit uses the color material data corresponding to the predetermined type in the block data of the one color block to cause the printing unit to print the color block, and performs the determination based on a difference between the color measurement value and the reference value in the block data of the one color block. The storage unit stores difference table data indicating, for each of the plurality of color patches, differences between each color measurement value obtained when printing on each of other types of printing media using color material data for reproducing the reference value on the predetermined type of printing medium and the reference value. The control unit selects the one color block from the plurality of color blocks with reference to the difference table data.

2. The printing device according to claim 1, wherein The control unit issues a predetermined warning to a user when a color measurement value obtained when printing on another type of printing medium using the color material data corresponding to the predetermined type in the block data of the one color patch differs from the reference value in the block data of the one color patch within a predetermined difference.

3. The printing device according to claim 1 or 2, characterized in that: The control unit selects colorant data as an update target from the colorant data stored in the storage unit, uses the selected colorant data, causes the printing unit to print a color block on a printing medium corresponding to the selected colorant data, adjusts the selected colorant data based on a comparison between a color measurement value obtained by the color measurement unit performing color measurement on the printed color block and the reference value of the color block corresponding to the selected colorant data, and uses the adjusted colorant data to update the selected colorant data in the storage unit.

4. A printing medium determination method, characterized in that: include: a block acquisition step of acquiring block data of one color block from a storage unit storing block data for a plurality of color blocks, the block data specifying the color of the color block; a printing step of causing a printing unit that prints by attaching a color material to a printing medium using the block data of the one color block to print the color block on the printing medium; as well as a judging step of judging whether the type of the printing medium on which the color patch is printed by the printing unit is a predetermined type based on a color measurement value obtained by a color measurement unit measuring the color of the color patch printed by the printing unit; The patch data stored in the storage unit includes a reference value representing the color of the color patch in a predetermined color space, and colorant data for each type of printing medium, the colorant data specifying the amount of the colorant used to reproduce the reference value on the printing medium. In the printing process, the printing unit prints the color patch using the color material data corresponding to the predetermined type in the block data of the one color patch, In the judging step, the judging is performed based on a difference between the color measurement value and the reference value in the block data of the one color block. In the judgment process, the one color block is selected from the multiple color blocks with reference to the difference table data, wherein the difference table data indicates, for each color block in the multiple color blocks, the difference between each color measurement value obtained when printing each other type of printing medium using the color material data for reproducing the reference value on the predetermined type of printing medium and the reference value.

5. A block selection method, characterized in that: include: an acquisition step of acquiring a reference value representing the color of a color patch in a predetermined color space and color material data defining an amount of color material for reproducing the reference value on a reference type of printing medium; as well as a difference calculation step of calculating the difference between each color measurement value obtained when printing on each printing medium of a comparative type different from the reference type using the color material data and the reference value; Changing the combination of the color block and the reference type, and repeating the acquisition process and the difference calculation process, The block selection method further includes a selection step of selecting, after the acquisition step and the difference calculation step are repeatedly performed, a color block for distinguishing the type of printing medium of the comparison type from the type of printing medium of the reference type based on the calculated difference.

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