阅读说明：本技术 打印装置、打印介质判断方法及块选择方法 (Printing apparatus, print medium determining method, and block selecting method ) 是由 永原敦示 于 2021-03-23 设计创作，主要内容包括：本公开涉及打印装置、打印介质判断方法及块选择方法,寻求改进以控制成本并适当地进行打印介质的判断。打印装置包括：将色料附着至打印介质而进行打印的打印部、进行颜色测量的颜色测量部、针对多个色块存储规定色块的颜色的块数据的存储部、以及控制部,所述控制部使用所述存储部存储的所述多个色块中的一个色块的块数据,使所述打印部向所述打印介质打印色块,并基于所述颜色测量部对由所述打印部打印的色块进行颜色测量得到的颜色测量值,来判断由所述打印部打印了色块的所述打印介质的类型是否为预定类型。(The present disclosure relates to a printing apparatus, a print medium judgment method, and a block selection method, seeking improvement to control costs and appropriately perform judgment of a print medium. The printing apparatus includes: the control unit causes the printing unit to print color patches on the printing medium using the block data of one of the color patches stored in the storage unit, and determines whether the type of the printing medium on which the color patches are printed by the printing unit is a predetermined type based on a color measurement value obtained by the color measurement unit performing color measurement on the color patches printed by the printing unit.)

1. A printing apparatus, comprising:

a printing unit that prints by attaching a coloring material to a printing medium;

a color measurement unit that performs color measurement;

a storage unit that stores block data specifying colors of color patches for a plurality of color patches; and

a control part for controlling the operation of the display device,

the control section causes the printing section to print a patch to the printing medium using block data of one of the plurality of patches stored by the storage section,

the control section determines whether the type of the printing medium on which the color patch is printed by the printing section is a predetermined type based on a color measurement value obtained by the color measurement section performing color measurement on the color patch printed by the printing section.

2. The printing apparatus of claim 1,

the block data stored by the storage section includes: reference values of colors of the patches are expressed in a predetermined color space, and coloring material data of each print medium type, which specifies amounts of the coloring materials for reproducing the reference values on the print medium.

3. The printing apparatus of claim 2,

the control section causes the printing section to print a color patch using color material data corresponding to the predetermined type in the block data of the one color patch, and makes the determination based on a difference value between the color measurement value and the reference value in the block data of the one color patch.

4. The printing apparatus of claim 3,

the storage section stores difference table data representing, for each of the plurality of color patches, a difference between each color measurement value obtained when each of other types of printing media is printed with toner data for reproducing the reference value to the predetermined type of printing medium and the reference value,

the control section selects the one color patch from the plurality of color patches with reference to the difference table data.

5. The printing apparatus of claim 4,

the control section issues a predetermined warning to a user when a difference value between a color measurement value obtained when printing is performed on another type of printing medium using the coloring material data corresponding to the predetermined type in the block data of the one color patch and the reference value in the block data of the one color patch is within a predetermined difference.

6. Printing device according to any of claims 2 to 5,

the control unit selects color material data to be updated from among the color material data stored in the storage unit, causes the printing unit to print a color patch on a printing medium corresponding to the selected color material data using the selected color material data, adjusts the selected color material data based on a comparison between a color measurement value obtained by color-measuring the printed color patch by the color measurement unit and the reference value of the color patch corresponding to the selected color material data, and updates the selected color material data in the storage unit using the adjusted color material data.

7. A print medium judging method, comprising:

a block acquisition step of acquiring block data of one color block from a storage unit that stores block data for a plurality of color blocks, the block data specifying colors of the color blocks;

a printing step of causing a printing unit, which performs printing by attaching a coloring material to a printing medium, to perform printing of a color patch on the printing medium, using block data of the one color patch; and

a determination step of determining whether or not the type of the printing medium on which the color patch is printed by the printing section is a predetermined type, based on a color measurement value obtained by color-measuring the color patch printed by the printing section by a color measurement section.

8. A block selection method, comprising:

an acquisition step of acquiring a reference value representing a color of a patch in a predetermined color space, and coloring material data specifying an amount of coloring material for reproducing the reference value on a reference type of printing medium; and

a difference value calculating step of calculating a difference value between each color measurement value obtained when each printing medium of a contrast type different from the reference type is printed using the toner data and the reference value,

changing a combination of the patch and the reference type, repeatedly performing the acquiring process and the difference value calculating process,

the block selection method further includes: a selecting step of selecting a color patch for discriminating from the printing medium of the comparison type, for each type of the printing medium as the reference type, based on the calculated difference, after the acquiring step and the difference calculating step are repeatedly executed.

Technical Field

The invention relates to a printing apparatus, a printing medium judging method and a block selecting method.

Background

There is disclosed an image forming apparatus that detects a paper type of a sheet to be conveyed based on a detection result of a media sensor provided in advance in a paper conveyance path and a paper type detection table provided in advance (see patent document 1).

Further, there is also disclosed a configuration in which, in a printer, a color measuring device that measures a pattern for color measurement recorded on roll paper to obtain a correction value for color calibration is provided at a position further downstream in a conveying direction than a carriage that holds a recording head (refer to patent document 2).

Documents of the prior art

Patent document

Patent document 1: JP 2016 laid-open No. 190707

Patent document 2: JP 2009-220290 publication

Disclosure of Invention

Problems to be solved by the invention

According to the above document 1, in order to detect the paper type of the paper, a dedicated media sensor needs to be provided in the apparatus, and therefore the apparatus cost increases. Therefore, improvement is required to appropriately judge the print medium while controlling the cost as much as possible.

Means for solving the problems

The printing apparatus includes: a printing section that performs printing by attaching a coloring material to a printing medium; a color measuring section for performing color measurement; a storage section that stores block data for a plurality of color patches, the block data specifying colors of the color patches; and a control section; the control portion prints a color patch to the print medium by the printing portion using block data of one of the plurality of color patches stored in the storage portion, and determines whether the type of the print medium on which the color patch is printed by the printing portion is a predetermined type, based on a color measurement value obtained by the color measurement portion performing color measurement of the color patch printed by the printing portion.

The print medium judging method includes: a block acquisition step of acquiring block data of one color block from a storage unit that stores block data of a color of a prescribed color block for a plurality of color blocks; a printing step of causing a printer to perform printing of color patches on the printing medium, the printer attaching a coloring material to the printing medium by block data of the one color patch to perform printing; and a determination step of determining whether or not the type of the printing medium on which the color patch is printed by the printing section is a predetermined type, based on a color measurement value obtained by color-measuring the color patch printed by the printing section by a color measurement section.

The block selection method comprises the following steps: an acquisition step of acquiring a reference value indicating a color of a patch in a prescribed color space, and coloring material data specifying a coloring material usage amount for reproducing the reference value on a reference type of printing medium; a difference value calculating step of calculating a difference value between each color measurement value obtained when printing on each printing medium of a contrast type different from the reference type using the toner data and the reference value; and a selecting step of changing a combination of the color patch and the reference type, repeatedly executing the acquiring step and the difference value calculating step, and selecting a color patch for judging the comparison type of the printing medium for each type of the printing medium as the reference type based on the calculated difference value after repeatedly executing the acquiring step and the difference value calculating step.

Drawings

Fig. 1 is a block diagram schematically showing the configuration of the apparatus.

Fig. 2 is a diagram showing a specific example of a configuration mainly corresponding to the printing section.

Fig. 3 is a flowchart showing the print color measurement processing.

Fig. 4 is a flowchart showing the spot color DB registration process.

Fig. 5A is a diagram showing an example of the spot color DB, and fig. 5B is a diagram showing an example of the spot color DB in which the selection result of the spot color block of each media type is registered.

Fig. 6 is a diagram illustrating the processing of steps S200 to S230 by a specific example.

Fig. 7 is a diagram showing an example of difference table data.

Fig. 8 is a diagram showing the difference table data of fig. 7 in another expression.

Fig. 9 is a diagram illustrating the processing of step S130 by a specific example.

Fig. 10A and 10B are diagrams each showing an example of the image data generated in step S130.

FIG. 11 is a flowchart showing color material data adjustment processing.

Fig. 12 is a diagram showing an example of the spot color DB in which partial information is updated.

Fig. 13 is a flowchart showing the difference table data update processing.

Description of the reference numerals

10 printing apparatus, 11 control section, 11a CPU, 11b ROM, 11c RAM, 12 program, 12a block selection processing section, 12b print control section, 12c color measurement control section, 12d medium determination section, 16 conveyance section, 17 carriage, 18 print head, 19 color measurement section, 20 storage section, 21 printing section, 30 printing medium, 40 spot color DB, 50 α, 50 β, 50 γ ICC profile, 60 difference table data, 73, 75 spot color block, 77 evaluation block.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings. The drawings are merely examples for illustrating the present embodiment. Since the drawings are illustrations, the proportion, the shape, or some of them may not be accurate, may not coincide with each other, or may be omitted.

1. The device comprises:

fig. 1 schematically shows the configuration of a printing apparatus 10 according to the present embodiment.

The printing apparatus 10 includes a control unit 11, a display unit 13, an operation receiving unit 14, a communication IF15, a conveying unit 16, a carriage 17, a print head 18, a color measuring unit 19, a storage unit 20, and the like. IF is an abbreviation for interface. The control section 11 is configured including one or more ICs having a CPU11a as a processor, a ROM11b, a RAM11c, and the like, and other nonvolatile memories and the like.

In the control unit 11, the CPU11a serving as a processor executes arithmetic processing using the RAM11c or the like as a work area in accordance with one or more programs 12 stored in the ROM11b or other memory or the like, thereby realizing various functions such as the block selection processing unit 12a, the print control unit 12b, the color measurement control unit 12c, the medium determination unit 12d, and the like. The processor is not limited to one CPU, and may be configured to execute processing by a plurality of hardware circuits such as CPUs and ASICs, or may be configured to execute processing in cooperation with a hardware circuit.

The display unit 13 is a device for displaying visual information, and is configured by, for example, a liquid crystal display, an organic EL display, or the like. The display unit 13 may include a display and a driving circuit for driving the display. The operation receiving unit 14 is a device for receiving a user operation, and is implemented by, for example, a physical button, a touch panel, a mouse, a keyboard, or the like. Of course, the touch panel may be implemented as one function of the display unit 13.

The display unit 13 and the operation receiving unit 14 may be a part of the configuration of the printing apparatus 10, or may be peripheral devices externally connected to the printing apparatus 10. The communication IF15 is a generic term of one or more IFs for connecting the printing apparatus 10 to the outside by wire or wirelessly in accordance with a predetermined communication protocol including a known communication standard.

The conveying unit 16 is a device for conveying a printing medium, and includes a roller, a motor for rotating the roller, and the like. The print head 18 ejects ink onto a print medium by an ink-jet method to perform printing. The color measuring unit 19 is a device for measuring the color of the object. The format of the color measurement value generated and output as the color measurement result by the color measurement unit 19 is, for example, L specified by CIE (international commission on illumination)^*a^*b^*L of color space^*a^*b^*The value, or the RGB value, which is a combination of the respective gradation values of red (R), green (G), and blue (B).

The carriage 17 is a mechanism driven by a carriage motor, not shown, and is movable back and forth in a first direction. The first direction is also referred to as a main scanning direction. As shown in fig. 2, the print head 18 is mounted on the carriage 17. The components including the conveyance unit 16, the carriage 17, and the print head 18 are collectively referred to as a printing unit 21. The printing section 21 may be any device capable of attaching a coloring material to a printing medium to perform printing. The colorant is ink or toner. The printing section 21 may be an ink jet system, or may be an electrophotographic system or a thermal system, for example, to perform printing. Further, in the present embodiment, the print head 18 is described as a serial print head that moves with the movement of the carriage 17, but a line type print head in which the print head does not move during ink ejection may also be used. The storage unit 20 may be implemented by a nonvolatile memory, an HDD, or other storage device. The storage unit 20 may be understood as a part of the control unit 11, and for example, the RAM11c may be understood as a part of the storage unit 20.

The configuration of the printing apparatus 10 shown in fig. 1 may be realized by one printer or may be realized by a plurality of apparatuses communicably connected.

That is, the printing apparatus 10 may actually be the printing system 10. The printing system 10 includes, for example, an information processing device functioning as the control unit 11, a storage unit 20, and a printer including a printing unit 21 and a color measurement unit 19. The printing apparatus 10 or the printing system 10 as described above realizes the print medium determination method and the block selection method according to the present embodiment.

Fig. 2 shows a specific example of a main printing section 21 as a part of the printing apparatus 10. In the upper part in fig. 2, the above-described specific example is shown from a perspective orthogonal to the conveying direction Df of the printing medium 30. Further, in the lower part in fig. 2, a part of the above specific example is shown from an upper perspective.

The conveying unit 16 includes a feed shaft 22 on the upstream side of conveyance and a take-up shaft 25 on the downstream side of conveyance. The conveyance upstream and conveyance downstream are simply expressed as upstream and downstream. The long-sized printing medium 30 wound around the feed shaft 22 and the take-up shaft 25 is stretched in the conveyance direction Df. The printing medium 30 is conveyed in the conveying direction Df. The print medium 30 may be paper, or may be a medium made of a material other than paper.

In the upper example of fig. 2, the feed shaft 22 rotates clockwise, feeding the printing medium 30 wound around the feed shaft 22 downstream. A front drive roller 23 is provided downstream of the feed shaft 22, and a rear drive roller 24 is provided upstream of the take-up shaft 25. The front drive roller 23 rotates clockwise, and conveys the printing medium 30 fed from the feeding portion 22 downstream. The front drive roller 23 is provided with a nip roller 23 n. The nip roller 23n abuts against the printing medium 30, thereby nipping the printing medium 30 between the nip roller 23n and the front drive roller 23.

The rear driving roller 24 rotates clockwise, and conveys the printing medium 30 conveyed downstream by the front driving roller 23 further downstream. A nip roller 24n is provided for the rear driving roller 24. The nip roller 24n abuts against the printing medium 30, thereby nipping the printing medium 30 between the nip roller 24n and the rear driving roller 24.

The print head 18 is disposed between the front driving roller 23 and the rear driving roller 24, and ejects ink from above onto the print medium 30. As can be seen from fig. 2, the print head 18 is mounted on the carriage 17. The print head 18 may eject a plurality of colors of ink, such as cyan (C), magenta (M), yellow (Y), black (K), and the like. Although illustration is omitted, the print head 18 has nozzle lines for each CMYK ink. The nozzle row corresponding to the ink of one color is constituted by a plurality of nozzles that eject the ink of one color, that is, a plurality of nozzles whose inter-nozzle distances (nozzle pitches) in the second direction D2 are fixed.

The print head 18 includes nozzles that open on a surface of the print head 18 facing the print medium 30, and the print head 18 determines whether to eject ink from the nozzles or not based on print data. The ink ejected by the nozzles is also referred to as ink drops or dots. The print head 18 is also referred to as a print head, an inkjet head, a liquid ejection head, or the like.

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

A 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 that conveys the printing medium 30. The number and arrangement of rollers provided in the middle of the conveyance pass for conveying the printing medium 30 are not limited to the form shown in fig. 2. The color of the ink discharged from the print head 18 is not limited to the above color. Of course, a flat base plate or the like that supports the printing medium 30 receiving the ink discharged from the print head 18 from below may be provided between the front driving roller 23 and the rear driving roller 24.

The label D1 indicates a first direction. In the example of fig. 2, the conveying direction Df is parallel to the first direction D1 between the front driving roller 23 and the rear driving roller 24. As shown in the lower part of fig. 2, the second direction D2 crosses the first direction D1. When the first direction D1 is referred to as the main scanning direction as described above, the second direction D2 is referred to as the sub-scanning direction. The first direction D1 and the second direction D2 may be understood as being orthogonal. In the example of fig. 2, an elongated guide rail 26 is provided above the printing medium 30 between the front driving roller 23 and the rear driving roller 24 in the first direction D1, and the carriage 17 is movable 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.

Further, the carriage 17 is movable in the second direction D2. For example, another mechanism such as a guide rail is provided for reciprocating the unit including 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 section 11. That is, the carriage 17 on which the print head 18 is mounted is movable two-dimensionally with respect to the surface of the print medium 30.

The movement of the carriage 17 in the second direction D2 corresponds to the relative movement of the carriage 17 and the printing medium 30 in the second direction D2. As the carriage 17 moves in the first direction D1, the action of the print head 18 ejecting ink is referred to as "main scanning". The main scan is also referred to as "pass". Further, the relative movement of the carriage 17 and the print medium 30 in the second direction D2 is referred to as "sub scanning".

In the example of fig. 2, the color measurement section 19 is provided at a downstream position of the carriage 17. The color measurement section 19 performs color measurement on the print medium 30 printed 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 perform color measurement on the printed printing medium 30.

2. Description of Spot color DB

Fig. 3 shows a print color measurement process according to the present embodiment by a flowchart. The print color measurement processing includes a print medium determination method. The print color measurement processing can be realized by the control section 11 executing processing according to the program 12. The judgment of the print medium in the present embodiment is processing for judging whether or not the type of the print medium 30 printed by the printing unit 21 is the type of the print medium designated by the user. The types of printing media are various, such as plain paper, glossy paper, other types than paper, and the like. The type of the printing medium designated by the user is referred to as "designated type". The specified type is also referred to as a predetermined type.

In step S120 of the print color measurement processing, the control section 11 acquires a spot color patch corresponding to the specified type from the spot color DB. DB is an abbreviation for database. The spot color block to be acquired in step S120 is registered in the spot color DB for each print medium type. The special color blocks corresponding to the specified types are blocks printed on the printing medium 30 for color measurement for the purpose of printing medium judgment (step S170).

Before describing the print color measurement processing of fig. 3, the spot color DB will be described.

Fig. 4 shows a flow chart of the spot color DB registration process executed by the control section 11 according to the program 12. The spot color DB registration process includes a block selection method.

In step S200, the block selection processing unit 12a acquires one of the spot colors from the spot color DB 40. The spot color DB40 is stored in the storage unit 20 in advance.

Fig. 5A shows an example of the spot color DB 40. In the spot color DB40, the correspondence relationship between the spot colors, which are the colors of the spot color patches, and the CMYK values for each print medium type, which are used for reproducing the spot colors on the print medium, is defined for the plurality of spot color patches P1, P2, P3, P4, and P5. Spot color patches P1, P2, P3, P4, P5 are patches different in spot color from each other.

In the spot color DB40, a spot color is defined by a predetermined color space. Specifically, by L^*a^*b^*L of color space^*a^*b^*The values define the spot color. The description of "") is appropriately omitted below. For example, the spot color patch P1 is (L, a, b) ═ 56, 66, 36), red or a color close to red. Further, the spot color patch P2 is (L, a, b) ═ (47, -2, -43), blue or a color close to blue. Such Lab values can become "reference values" for the colors of the spot color blocks. However, the color space defining the reference value may also be L^*C^*h^*Color space or XYZ color space.

In the spot color DB40, CMYK values for reproducing a spot color on a print medium are defined for each of a plurality of media types α, β, and γ of the print medium. The CMYK values are a combination of gradation values representing the ink amounts of each CMYK. The gradation value is represented by, for example, a 256 gradation range of 0 to 255. The CMYK values correspond to "color material data". For example, the CMYK value required to reproduce the Lab value of the private color patch P1 through the printing medium of the media type α is (C, M, Y, K) ═ (1, 84, 71, 0). Further, the CMYK value required to reproduce the Lab value of the private color patch P2 through the print medium of the media type β is (C, M, Y, K) ═ (95, 61, 6, 0).

The CMYK values specified in the spot color DB40 can be calculated using a so-called ICC profile. That is, an ICC profile 50 α for the media type α, which specifies a conversion relationship of CMYK values and Lab values, which are color measurement values of patches reproduced by the print medium of the media type α by the CMYK values, is prepared in advance. Similarly, an ICC profile 50 β for media type β and an ICC profile 50 γ for media type γ are prepared in advance, the ICC profile 50 β for media type β specifies a conversion relationship of CMYK values with color measurement values (Lab values) of blocks reproduced by a print medium of media type β by CMYK values, and the ICC profile 50 γ for media type γ specifies a conversion relationship of CMYK values with color measurement values (Lab values) reproduced by a print medium of media type γ by CMYK values. The CMYK values specified in the spot color DB40 for each spot color patch and each media type are data calculated using the Lab values of the spot color patches and such an ICC profile. The spot color DB40 having Lab values and CMYK values as reference values for each spot color patch as described above specifies block data for each patch, the block data specifying the color of the patch.

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

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

The media type corresponding to the CMYK values acquired in step S210 is referred to as a "reference type" for convenience.

Such steps S200, S210 correspond to an acquisition process of acquiring reference values representing colors of patches by a predetermined color space, and coloring material data for reproducing the reference values to a reference type of printing medium.

In step S220, the block selection processing section 12a calculates Lab values for each media type using the CMYK values acquired in step S210 and the ICC profile for each media type.

In step S230, the block selection processing unit 12a compares the Lab value of each media type calculated in step S220 with the spot color acquired in step S200, and calculates the color difference of each media type.

Such steps S220 and S230 include a difference value calculation step of calculating a difference value between each color measurement value obtained when printing on each printing medium of a contrast type different from the reference type using the coloring material data acquired in the acquisition step and the reference value acquired in the acquisition step.

Fig. 6 is a diagram illustrating the processing of steps S200 to S230 by a specific example. In the example of fig. 6, the spot color of the spot color patch P1 is acquired by step S200, and the CMYK values for reproducing the spot color patch P1 to the print medium of the media type α are acquired by step S210, where (C, M, Y, K) ═ 1, 84, 71, 0. That is, in the example of fig. 6, the media type α is a reference type. In step S220, the block selection processing unit 12a inputs the values (C, M, Y, K) — (1, 84, 71, 0) to the ICC profile 50 α, the ICC profile 50 β, and the ICC profile 50 γ, and calculates Lab values, which are conversion results of the ICC profiles 50 α, 50 β, and 50 γ. ICC profiles 50 α, 50 β, 50 γ are stored in the storage section 20.

In the example of fig. 6, the block selection processing section 12a calculates (L, a, b) ═ 56, 66, 36 as the conversion result of the ICC profile 50 α, calculates (L, a, b) ═ 61, 55, 34 as the conversion result of the ICC profile 50 β, and calculates (L, a, b) ═ 52, 57, 37 as the conversion result of the ICC profile 50 γ in step S220. In step S230, the patch selection processing unit 12a compares the Lab value as the conversion result with the spot color of the spot color patch P1 to calculate a color difference.

Note that the Lab value obtained by converting the CMYK values for reproducing the spot color patch P1 on the print medium of the media type α by the ICC profile 50 α is the spot color of the spot color patch P1, and thus the associated color difference is 0 as shown in fig. 6.

According to the example of fig. 6, the color difference of the Lab value obtained by converting the CMYK values for reproducing the spot color patch P1 to the print medium of the media type α by the ICC profile 50 β from the spot color of the spot color patch P1 is 3.3. This indicates that, when a print medium of the medium type β is erroneously printed by CMYK values for reproducing the spot color patch P1 on the print medium of the medium type α, the printed patch has a color difference of 3.3 from the original color of the spot color patch P1.

According to the example of fig. 6, the color difference of the Lab value obtained by converting the CMYK values for reproducing the spot color patch P1 to the print medium of the media type α by the ICC profile 50 γ from the spot color of the spot color patch P1 is 3.4. This indicates that, when a print medium of the medium type γ is erroneously printed by CMYK values for reproducing the spot color patch P1 in the print medium of the medium type α, the printed patch has a color difference of 3.4 from the original color of the spot color patch P1.

In step S240, the block selection processing section 12a determines whether the CMYK values of each media type corresponding to the spot color acquired in step S200 have been completely acquired from the spot color DB40 in step S210. Then, if there are CMYK values not acquired, the determination from no in step S240 returns to step S210, CMYK values corresponding to another media type are acquired, and steps S220 and S230 are executed. On the other hand, when the CMYK values of each media type corresponding to the spot color acquired in step S200 have been completely acquired from the spot color DB40 through step S210, the yes judgment from step S240 proceeds to step S250.

In step S250, the block selection processing unit 12a determines whether or not the spot color of the spot color block has been completely acquired from the spot color DB40 in step S200. If there is a spot color that is not acquired, the determination of no in step S250 returns to step S200, another spot color is acquired, and steps S210 and beyond are executed. On the other hand, when the spot color of the spot color patch has been completely acquired from the spot color DB40 in step S200, the yes judgment in step S250 proceeds to step S260.

As a result of the determination in each of steps S240 and S250, the combination of the patch and the reference type is changed, and the acquiring step (steps S200 and S210) and the difference value calculating step (steps S220 and S230) are repeatedly executed.

When the determination in step S250 is yes, the block selection processing unit 12a calculates the color difference for each media type for all the CMYK values defined in the spot color DB 40.

In step S260, the block selection processing portion 12a generates difference table data 60 representing the color differences of the respective media types calculated in step S230 in a table format, and stores the difference table data 60 in the storage portion 20.

Fig. 7 shows an example of the difference table data 60. As shown in fig. 7, the difference table data 60 is composed of difference tables 60P1, 60P2, 60P3, 60P4, and 60P5 in which color differences are summarized for each of the spot color patches P1, P2, P3, P4, and P5. The difference table of fig. 7 represents the difference in Lab value when the corresponding spot patch is printed to the reference type and the Lab value when printed to the comparison type. For example, the difference table 60P1 corresponding to the spot color patch P1 represents the color difference of the Lab value when the spot color patch P1 is printed to the reference type and the Lab value when printed to the contrast type. The "Lab value at the time of printing" is a color measurement value obtained by performing color measurement after printing, and such a color measurement value is calculated using the ICC profile in step S220. The comparison type is the type of the medium corresponding to each Lab value calculated in step S220. The reference type can be understood to be included in the comparison type, and the reference type can also be understood not to be included in the comparison type. In the difference table 60P1, for example, a color difference of 3.3 is defined for the relationship between the reference type α and the comparison type β, and a color difference of 3.4 is defined for the relationship between the reference type α and the comparison type γ, which are color differences shown in fig. 6.

Fig. 8 shows the difference table data 60 in other expressions. In fig. 8, the difference table data 60 is composed of difference tables 60 α, 60 β, 60 γ in which the color difference is summarized for each reference type (media types α, β, γ). The difference table data 60 shown in fig. 7 is different from the difference table data 60 shown in fig. 8 only in the form of representation, and the contents thereof are the same. For example, the difference table 60 α is a table in which the color difference corresponding to the reference type, that is, the media type α, is extracted from each of the difference tables 60P1, 60P2, 60P3, 60P4, and 60P 5. In the present embodiment, the difference table data 60 of the two expressions shown in fig. 7 and 8 is not necessarily required, and only one of them is required. For ease of understanding, the difference table data 60 is shown in both fig. 7 and 8.

In step S270, the block selection processing unit 12a selects a spot color block for each of the media types α, β, and γ with reference to the difference table data 60, and registers the result of the selection in the spot color DB 40. Step S270 corresponds to a selection process of selecting a patch for discrimination from a print medium of a comparison type with respect to the type of each print medium as a reference type based on the difference values calculated by steps S200 to S250. The block selection processing unit 12a selects a block having a larger average color difference, for example. The average color difference referred to herein means an average value of color differences of each comparison type with respect to the reference type. For example, regarding the spot color patch P1 of the difference table 60 α, the color difference between the reference type α and the contrast type β is 3.3, the color difference between the reference type α and the contrast type γ is 3.4, and the average value thereof is 3.35. According to the difference table 60 α of fig. 8, the largest average value of the color differences of the contrast type is the spot color patch P1. That is, with the CMYK values for printing the special patch P1 to the media type α, there is a significant color difference between the Lab value obtained when the media type β or the media type γ is erroneously printed and the spot color of the special patch P1. Therefore, the block selection processing section 12a selects the spot color block P1 from the spot color blocks P1, P2, P3, P4, and P5 for the media type α.

Further, according to the difference table 60 β, the spot color patch P5 is the largest in the average value of the color differences of the contrast type. That is, with the CMYK values for printing the special patch P5 to the media type β, there is a significant color difference between the Lab value obtained when the media type α or the media type γ is erroneously printed and the spot color of the special patch P5. Thus, the block selection processing section 12a selects the private block P5 for the media type β. Similarly, according to the difference table 60 γ, the largest average value of the color differences of the contrast type is the spot color patch P1. That is, with the CMYK values for printing the special patch P1 to the media type γ, there is a significant color difference between the Lab value obtained when the media type α or the media type β is erroneously printed and the spot color of the special patch P1. Thus, the block selection processing section 12a selects the private block P1 for the media type γ.

The spot color DB40 after registering such selection results of the blocks of each media type is depicted in fig. 5B. According to fig. 5B, in the spot color DB40, a spot color patch P1 is registered in correspondence with the media type α. Similarly, according to fig. 5B, a private patch P5 selected corresponding to the media type β and a private patch P1 selected corresponding to the media type γ are registered, respectively.

As above, the spot color DB registration process of fig. 4 ends.

3. Print color measurement processing:

next, the print color measurement processing of fig. 3 is explained on the premise that the spot color DB registration processing has been executed.

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

In step S110, the print control unit 12b acquires the print condition of the image. The print condition is also acquired as information designated by the user through the operation of the operation receiving unit 14. Alternatively, the print condition may be information or the like set in advance in association with the image data acquired in step S100. The printing conditions refer to information including the type of printing medium, the size of printing medium related to one printing, the number of passes, the amount of sub-scanning, and the like. The type of the printing medium in the printing condition is a specified type. The print medium size is expressed by the medium width x the medium length. In the example of FIG. 2, the media length is the length in the first direction D1 and the media width is the length in the second direction D2. In the present embodiment, one-time printing is also referred to as one-frame printing, and the print medium size is also referred to as a frame size.

The pass number is the number of passes required for one frame printing. The sub-scanning amount is a distance of sub-scanning performed between passes required for one-frame printing and passes.

The order of steps S100 and S110 may not be as shown in fig. 3, and steps S100 and S110 may be processes executed substantially simultaneously or in the reverse order to the order shown in fig. 3.

In step S120, the print control section 12b acquires a spot color patch corresponding to the designated type from the spot color DB40 stored in the storage section 20. According to the example of fig. 5B, if the specified type is the media type α, the print control section 12B acquires information of the private block P1. Further, if the specified type is the media type β, the print control section 12b acquires information of the private patch P5, and if the specified type is the media type γ, the print control section 12b acquires information of the private patch P1. Step S120 corresponds to a block acquisition step of acquiring block data of one color block from the storage unit 20.

In step S130, the print control unit 12b generates image data to which the spot color patch acquired in step S120 is added. Specifically, the print control section 12b first arranges the images in accordance with the frame size. That is, the image data acquired in step S100 is arranged in accordance with the frame size under the printing condition acquired in step S110, thereby generating image data for one-frame printing. Then, the print control unit 12b synthesizes the spot color block at a predetermined position in the frame-sized image data.

Fig. 9 is a diagram illustrating the processing of step S130 using a specific example. The upper mark 70 of fig. 9 indicates the image data acquired in step S100. The image data 70 represents a star image 71 drawn in a certain color. The content of the image 71 is arbitrarily determined by the user. In the example of fig. 9, the image data 70 is image data of 13 inches in length and 9 inches in width. Also shown in fig. 9 are the correspondence of image data to the directions D1, D2.

The contents of the print conditions acquired in step S110 are various, and here, in order to explain fig. 9, it is assumed that the frame size is 13 inches in media width × 36 inches in media length. At this time, in step S130, the print control section 12b copies the image data 70 and arranges four in succession corresponding to the first direction D1, thereby generating the image data 72 for one-frame printing as shown in the middle of fig. 9. In step S130, the print control section 12b may also enlarge or reduce the image data 70 as necessary.

Further, in step S130, the print control section 12b synthesizes the private patches 73 at predetermined positions in the image data 72, and generates the image data 74 as shown in the lower part of fig. 9. The predetermined position here is, 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 downstream as possible in the image data 72. Further, the print control section 12b synthesizes the private patch 73 at a position not overlapping the image 71 in the image data 72. Here, assuming that the specified type is the media type α, the spot color patch 73 is a spot color patch P1. That is, the print control section 12b acquires CMYK values corresponding to the media type α of the spot color patch P1 from the spot color DB40, and synthesizes the spot color patch 73, which is an image area formed by a set of pixels having the acquired CMYK values, in the image data 72.

In step S140, the print control unit 12b performs necessary image processing on the image data 74 generated in step S130 to generate print data for the printing unit 21 to perform printing. The print control unit 12b performs, for example, color conversion processing on the image data 74. That is, the RGB values of the respective pixels constituting the image data 74 are converted into CMYK values with reference to a color conversion LUT generated in advance. LUTs are abbreviations for look-up tables. The color conversion LUT is a table that specifies a correspondence relationship between RGB values and CMYK values. Note that the region corresponding to the spot color patch 73 in the image data 74 does not need to perform such color conversion processing.

The print control unit 12b further performs halftone processing on the image data 74. Through the color conversion process, the image data 74 becomes a state in which each pixel has CMYK values. The image data 74 is print data in which ink ejection (dot on) or ink non-ejection (dot off) is specified for each pixel and each CMYK by the halftone processing. Of course, the dot opening information in the print data may be information for specifying which of a plurality of sizes of dots such as a large dot, a medium dot, and a small dot is to be ejected. The halftone processing may be performed by, for example, a dither method or an error diffusion method.

In step S150, the print control unit 12b causes the printing unit 21 to perform one-frame printing based on the print data and the print conditions. That is, the print control unit 12b controls the movement of the carriage 17 in the first direction D1 and the second direction D2 based on the number of passes and the sub-scanning amount in the print condition, and causes the print head 18 to eject ink based on the print data. The print head 18 ejects or does not eject ink of each of CMYK colors from each nozzle in each pass based on dot on/dot off information defined for each pixel in print data. As a result, the image 71 represented by the image data 74 and the spot color patch 73 are printed within the range of one frame size of the printing medium 30. Step S150 corresponds to a printing process, and causes the printing section 21 to print patches on the print medium 30. In the one-frame printing period in step S150, the conveying unit 16 does not convey the printing medium 30. That is, in step S150, pass and sub-scan are performed on the printing medium 30 in the stationary state.

In step S160, the color measurement control section 12c controls the color measurement section 19 to perform color measurement on the spot patches printed on the print medium 30. According to the example of fig. 9, the color measurement section 19 performs color measurement on the dedicated patches 73 printed on the print medium 30, and outputs the color measurement value obtained by the color measurement to the control section 11. Of course, the conveying section 16 conveys the printing medium 30 by a necessary distance after step S150 and before step S160 so that the color measuring section 19 performs color measurement on the spot color patches 73.

In step S170, the medium judging section 12d judges whether the type of the printing medium 30 on which the special patches are printed by the printing section 21 is the designated type based on the color measurement value obtained by the color measurement of the special patches in step S160. Steps S170 and S180 correspond to a determination step. At this time, the medium judging section 12d calculates a color difference between the color measurement value of the spot color patch and the spot color corresponding to the specified type. Assuming that the designated type is the media type α as described above, in step S120, the information of the spot color patch P1 is acquired from the spot color DB40, so the media judgment section 12d can calculate the color difference by comparing the Lab value (56, 66, 36) indicating the color of the spot color patch P1 with the color measurement value of the spot color patch obtained in step S160.

Then, the medium judging section 12d compares the color difference calculated in this way with a predetermined threshold value relating to the color difference, and judges whether the color difference is less than the threshold value or not. Regarding the threshold value related to the color difference used for the judgment in step S170, referring to fig. 8, for example, a suitable threshold value is about 2.0. The threshold value may be arbitrarily set by the user.

In step S180, the medium determination unit 12d branches the process according to the determination result in step S170. When the color difference < the threshold value, the medium judging section 12d judges that the type of the printing medium 30 on which the private patch is printed by the printing section 21 is the designated type, that is, that the printing medium 30 is appropriate (step S180: YES), and ends the printing color measurement processing of FIG. 3. On the other hand, when the color difference is equal to or larger than the threshold value, the medium determining section 12d determines that the type of the printing medium 30 is not the designated type, that is, the printing medium 30 is not appropriate (step S180: NO), and the process proceeds to step S190.

Although not shown in fig. 3, the control unit 11 may continue to control the printing unit 21 to print the next frame after the print color measurement processing is finished in accordance with the yes determination in step S180.

In step S190, the control unit 11 executes the media error process and ends the flowchart of fig. 3. The media error process refers to, for example, a process of stopping a print-related action. That is, since the print medium 30 of the type different from the type desired by the user is currently set in the printing section 21, the control section 11 stops driving the printing section 21 and ends the flowchart of fig. 3. This prevents the printing medium 30 and ink from being wasted more. As one of the media error processes, the control unit 11 may display a warning screen on the display unit 13 to notify the user that the print medium 30 is not appropriate.

In the example of fig. 9, the image 71 in the image data 74 is represented in the same color as the spot color patch 73. That is, in the print color measurement processing of fig. 3, the image acquired in step S100 and the spot color patch added in step S130 may be printed in the same color. At this time, the print control section 12b may generate, in step S130, image data 74 including an image 71 expressing each pixel color with the same CMYK values as those of the spot color patch acquired from the spot color DB40 according to the specified genre in step S120, and the spot color patch 73. As described above, 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 by the color measurement in step S160, can determine not only the determinations in steps S170 and S180 but also whether the color of the image 71 in the print result is appropriate. The control section 11 determines whether the color of the image 71 in the print result is appropriate based on the color measurement value of the specific patch 73, so that the determination result can be notified to the user, or color calibration of the image 71 or the like can be performed as necessary.

4. Other examples of block printing:

fig. 10A shows an example of the image data 74 generated in step S130, which is different from the example shown in fig. 9. The image data 74 shown in fig. 10A includes a plurality of special blocks 73, 75. That is, the print control section 12b can print a plurality of special patches to the print medium 30 together with the image 71.

In explaining fig. 10A, it is assumed that the specified type is the media type β. Note that in the spot color DB40 described above, the spot color patches P1 to P4 are defined, and the spot color patch P5 is not defined. Therefore, in the difference table data 60 shown in fig. 8, information on the color difference corresponding to the spot patch P5 does not exist in the difference tables 60 α, 60 β, and 60 γ. At this time, in step S270 of the spot color DB registration process (fig. 4), the block selection processing section 12a selects and registers the spot color block P1 and the spot color block P4 for the media type β in the spot color DB 40. That is, according to the difference table 60 β, when the spot patch P5 is not present, a spot patch having a sufficiently large color difference from either of the media types α and γ is not present. The color difference is sufficiently large, which means that the color difference is equal to or larger than the threshold value used for the determination in step S170. Therefore, the block selection processing section 12a selects the spot color block P1 as a spot color block for the contrast media type β and the media type α, and selects the spot color block P4 as a spot color block for the contrast media type β and the media type γ.

In this situation, when the specified type is the media type β, the print control section 12b acquires the information of the spot color patch P1 and the spot color patch P4 from the spot color DB40 in step S120 of fig. 3. Then, in step S130, the print control section 12b generates the image data 74 in which the spot patch 73 having CMYK values of each pixel corresponding to the media type β of the spot patch P1 and the spot patch 75 having CMYK values of each pixel corresponding to the media type β of the spot patch P4 are added. As a result, the spot patches 73 and 75 are printed on the printing medium 30 together with the image 71, and the medium determination section 12d performs the determination in steps S170 and S180 using the color measurement values of the spot patches 73 and 75. At this time, the medium judging section 12d compares the color difference between the color measurement value of the spot patch 73 and the Lab value of the spot patch P1 defined in the spot color DB40 and the color difference between the color measurement value of the spot patch 75 and the Lab value of the spot patch P4 defined in the spot color DB40 with the threshold values, and judges no in step S180 if any of the color differences is greater than or equal to the threshold value.

Fig. 10B shows an example of the image data 74 generated in step S130, which is different from the examples shown in fig. 9, 10A. The color of the image that should be printed to the print medium 30 is of course different from the color of the spot color patch that is printed with the image. In the example of fig. 10B, the image 76 and the spot color patch 73 included in the image data 74 are different in color. At this time, the print control unit 12b may include the image 76 and the dedicated block 73 in the image data 74, and may further include an evaluation block 77 having the same color as the image 76. As a result, the spot color patch 73 and the evaluation patch 77 are printed together with the image 76 on the printing medium 30, and the medium determination section 12d performs the determination in steps S170 and S180 using the color measurement value of the spot color patch 73. Further, the control portion 11 may determine whether the color of the image 76 in the print result is appropriate based on the color measurement value of the block 77 for evaluation.

5. To summarize:

according to the present embodiment, the printing apparatus 10 includes a printing unit 21 that prints by attaching a coloring material to a printing medium, a color measurement unit 19 that performs color measurement, a storage unit 20 that stores block data of a predetermined color patch color for a plurality of color patches, and a control unit 11. The control section 11 causes the printing section 21 to print the patch to the printing medium using the block data of one patch among the plurality of patches stored by the storage section 20, and determines whether the type of the printing medium on which the patch is printed by the printing section 21 is a predetermined type based on a color measurement value obtained by the color measurement section 19 performing color measurement on the patch printed by the printing section 21.

According to the above configuration, it is possible to determine whether or not the type of the printing medium used by the printing unit 21 is the designated type by using the color measuring unit 19 that performs color measurement on the image and the patch without using a dedicated medium sensor for detecting the type of the paper. Thus, costs can be controlled and the print medium can be judged. Further, using the color measurement values of the patches measured by the color measurement section 19, not only the print medium but also the color of the print result can be evaluated and judged.

Further, according to the present embodiment, the block data stored by the storage section 20 includes reference values representing the colors of patches in a predetermined color space, and coloring material data for each type of printing medium, which specifies the amount of coloring material used for reproducing the reference values on the printing medium.

According to the above configuration, the control section 11 can cause the printing section 21 to print a patch to the printing medium using the coloring material data for reproducing the reference value of the one patch stored in the storage section 20, and determine whether or not it is the specified type based on the color measurement value and the reference value of the patch.

Further, according to the present embodiment, the control portion 11 causes the printing portion 21 to print a patch using the coloring material data corresponding to a predetermined type in the block data of the one patch, and makes the determination based on the difference between the color measurement value and the reference value in the block data of the one patch.

According to the above configuration, the printing section 21 evaluates the difference between the color measurement value and the reference value that should theoretically be matched if the specified type of printing medium is used, and thereby can accurately determine whether or not the specified type is used.

Further, according to the present embodiment, the storage section 20 stores the difference value between each color measurement value obtained when printing to each of the other types of printing media using the coloring material data for reproducing the reference value to the predetermined type of printing medium and the reference value, to the difference value table data 60 represented for each of the plurality of patches. Then, the control section 11 selects the one patch from the plurality of patches with reference to the difference value table data 60.

According to the above configuration, the control section 11 can select a patch that is most suitable for determining whether or not the designated type is selected from the plurality of patches.

In addition to the printing apparatus 10, the present embodiment discloses various inventions such as a method and a program. The print medium judging method includes: a block acquisition step of acquiring block data of one patch from a storage unit 20 that stores block data of a predetermined patch color for a plurality of patches; a printing step of causing a printing section 21, which performs printing by attaching a coloring material to a printing medium, to perform printing of color patches on the printing medium using block data of the one color patch; and a determination step of determining whether or not the type of the printing medium on which the color patches are printed by the printing section 21 is a predetermined type, based on a color measurement value obtained by the color measurement section 19 performing color measurement on the color patches printed by the printing section 21.

Further, according to the present embodiment, a block selection method includes: an acquisition step of acquiring reference values representing patch colors in a predetermined color space, and coloring material data specifying amounts of coloring materials for reproducing the reference values on a reference type of printing medium; and a difference value calculating step of calculating a difference value between each color measurement value obtained when the toner data is printed on each printing medium of a contrast type different from the reference type and the reference value. Then, the combination of the color patches and the reference types is changed, and the acquiring process and the difference value calculating process are repeatedly performed. The block selection method further includes a selection step of selecting a color block for discrimination from the printing medium of the comparison type for each type of the printing medium of the reference type based on the calculated difference after the acquisition step and the difference calculation step are repeatedly executed.

According to the block selection method, a color block most suitable for comparison with other types of printing media can be selected for each type of printing media. Therefore, by using the color patch selected in this way, the print medium can be accurately judged.

6. Modification example:

further, modifications included in the present embodiment will be described.

First modification example:

the control portion 11 may issue a predetermined warning to the user when a difference value between a color measurement value obtained when printing is performed on another type of printing medium using color material data corresponding to a predetermined type in the block data of the one color patch and a reference value of the block data of the one color patch is within a predetermined difference.

According to the example of the difference table data 60 shown in fig. 7, 8, spot color patches having an average color difference higher than 3.0 with respect to the contrast type can be selected for the media types α, β, γ. However, according to the results up to step S260 in the spot color DB registration process of fig. 4, it is not always possible to select spot colors having sufficiently high color differences with the contrast types for the media types α, β, and γ. For example, regarding the media type β, it is assumed that the average color difference from each media type α, γ as a comparison type is lower than a prescribed difference "2.0" in all the spot patches. At this time, the control unit 11 needs to select and register a patch having the largest average color difference with the contrast type for the media type β. In step S270, the control unit 11 selects a spot color patch P3 having an average color difference of, for example, "1.8" from each of the media types α and γ as the contrast type for the media type β.

At this time, in the print color measurement processing of fig. 3, assuming that the designated type is the media type β, the control section 11 issues a predetermined warning to the user when acquiring information of the spot color patch P3 from the spot color DB40 according to the designated type in step S120. The content of the warning referred to herein is: the determination accuracy of whether or not the specified type is determined by the spot color patch P3 printed to the print medium 30 because the specified type is the media type β is low. Further, at the same time as such warning, the control section 11 may also stop driving the printing section 21 similarly to step S190. The user can instruct the control section 11 to continue or cancel the processing after step S130, knowing that the judgment accuracy of the special patches is low. According to this configuration, the user can be prevented from being adversely affected by continuing printing without being aware of a low judgment accuracy of the spot color patch.

Second modification example:

the CMYK values corresponding to the spot color patches and the media types in the spot color DB40 of fig. 5A, 5B are values calculated based on the Lab values of the spot color patches and the ICC profile of each media type. The control section 11 may also adjust CMYK values in such a spot color DB40 based on actual printing and color measurement. That is, the control section 11 selects the color material data to be updated from among the color material data stored in the storage section 20, causes the printing section 21 to print a color patch on the printing medium corresponding to the selected color material data using the selected color material data, adjusts the selected color material data based on the comparison between the color measurement value obtained by color-measuring the printed color patch by the color measurement section 19 and the reference value of the color patch corresponding to the selected color material data, and updates the selected color material data in the storage section 20 using the adjusted color material data.

Fig. 11 illustrates color material data adjustment processing of adjusting CMYK values of the spot color DB40 by a flowchart. The color material data adjustment processing will be described with reference to a case where CMYK values corresponding to the media type α are adjusted.

In step S300, the control unit 11 acquires CMYK values of the respective spot color patches P1, P2, P3, P4, and P5 corresponding to one media type, that is, the media type α, from the current spot color DB 40. Step S300 corresponds to a process of selecting color material data to be updated. When the control section 11 first executes the color material data adjustment process for the medium type α, CMYK values may be acquired as default values in step S300. The default values of CMYK values are values calculated based on the Lab values of the spot color patches and the ICC profile of each media type, and are CMYK values shown in the spot color DB40 of fig. 5A and 5B.

In step S310, a color table is generated based on the CMYK values of the individual patches acquired in step S300. The color table is image data representing a plurality of color patches different in color from each other. The control section 11 generates color patches of CMYK values of one of the private color patches acquired in step S300 and a plurality of color patches corresponding to a plurality of CMYK values obtained by changing the gradation values of at least one of the ink colors CMYK from the CMYK values. The control section 11 repeatedly executes, for each spot patch in this manner, processing of adding patches of colors slightly different from the CMYK values of one spot patch, thereby generating a color table.

In step S320, the control unit 11 performs necessary image processing on the color chart generated in step S310 to generate print data for printing the color chart.

In step S330, the control unit 11 causes the printing unit 21 to print the color chart on the printing medium of the corresponding media type based on the print data generated in step S320. The corresponding media type is of course in this case the media type alpha. When the user causes the printing apparatus 10 to execute the toner data adjustment process for the medium type α, the printing medium 30 of the medium type α is set in the printing section 21.

In step S340, the control section 11 causes the color measurement section 19 to perform color measurement on the color chart printed on the printing medium 30 of the medium type α in step S330, thereby acquiring the color measurement value of each patch of the color chart.

In step S350, the control unit 11 calculates a new CMYK value corresponding to the Lab value of each spot color patch based on the comparison between the color measurement value of each spot color patch acquired by the color measurement in step S340 and the Lab value of each spot color patch defined in the spot color DB 40. Step S350 is a process for adjusting CMYK values. The step S350 may employ various methods including a well-known method. For example, the control section 11 may map the color measurement values of the respective patches into a Lab space, and calculate CMYK values corresponding to the Lab values of the respective patches with higher accuracy by interpolation or the like based on the positional relationship between the Lab values of the respective dedicated patches and the Lab values of the respective patches. The CMYK values calculated in this way are new CMYK values corresponding to the Lab values of the spot patches.

In step S360, the control unit 11 updates the CMYK values of the respective spot color patches defined in the current spot color DB40 in association with the media type α, using the new CMYK values calculated for the respective spot color patches in step S350. As a result, the CMYK values of each spot color to be reproduced more accurately on the print medium of the medium type α are specified in the spot color DB 40.

In the above, the toner data adjustment processing for the media type α is completed once. As shown by the broken line arrow in fig. 11, the control unit 11 may repeatedly execute the toner data adjustment process for the medium type α. By repeating this process, the spot color reproduction accuracy of the CMYK values specified by the spot color DB40 can be further improved.

Fig. 12 shows the spot color DB40 in which partial information is updated after the toner data adjustment processing for the media type α. When the spot color DB40 of fig. 12 is compared with the spot color DB40 of fig. 5A and 5B, the CMYK values of the respective spot color patches P1, P2, P3, P4, P5 corresponding to the media type α surrounded by the dotted line frame are updated. Of course, the control section 11 may execute the coloring material data adjustment processing for the media type β and the coloring material data adjustment processing for the media type γ in the same manner as the coloring material data adjustment processing for the media type α.

The control unit 11 may perform the spot color DB registration process shown in fig. 4 by referring to the spot color DB40 in which the CMYK values are updated in this manner. According to the spot color DB registration processing performed with reference to the spot color DB40 after update, the value of the color difference calculated in step S230 is different from that of the spot color DB registration processing performed with reference to the spot color DB40 before update. Therefore, the spot color patches selected for each media type in step S270 may also be different from the spot color patches selected by the spot color DB registration processing before, and as a result, the registration of the spot color patches for each media type in the spot color DB40 is also updated.

The third modification example:

in the print color measurement processing of fig. 3, when the determination in step S180 is "no", the control section 11 may execute the processing shown in fig. 13 as one of the media error processing (step S190). Fig. 13 shows the difference table data update processing by a flowchart.

In step S400, the control unit 11 displays an error notification that the printing medium 30 is inappropriate via the warning screen, and displays an input request for the usage type. The usage type refers to the type of printing medium currently set in the printing section 21 for the printing of step S150.

In step S410, the control unit 11 receives an input of a usage type from the user. The user who sees the warning screen of step S400 recognizes that the usage type should be input because the specified type is different from the usage type. The user confirms the printing unit 21, determines the use type, and operates the operation reception unit 14 to input the use type.

The control unit 11, which recognizes the use type from the user input, updates the difference table data 60 based on the use type and the color difference calculated in the determination 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 (step S420). For example, assuming that the designated type is the media type α, the control unit 11 prints the spot patch P1 corresponding to the media type α on the print medium 30 in step S150, determines the color difference calculated in step S170 to be "2.8", and determines no in step S180. The usage type received in step S410 is the media type γ. In this case, in step S420, the control unit 11 updates the color difference "3.4" defined in the difference table data 60 shown in fig. 7 and 8 with respect to the relationship among the spot color patch P1, the reference type α, and the contrast type γ to the color difference "2.8".

As such, the difference table data 60 is updated based on the color difference calculated in step S170 from the actual color measurement result of the special patch, and the information of the use type, and the accuracy of the difference table data 60 can be improved. The control unit 11 may execute step S270 of fig. 4 after updating the difference table data 60 in step S420. That is, the spot color patch selection and the registration of the spot color DB40 for each media type are newly performed with reference to the difference table data 60 whose accuracy is improved by the update. As a result, the spot color patches suitable for discrimination from other types of printing media can be selected more accurately for each media type.

Other examples are as follows:

the relative movement of the carriage 17 and the print medium 30 in the second direction D2, that is, the sub-scanning may be performed by conveying the print medium 30 instead of moving the carriage 17 in the second direction D2. That is, the conveying direction Df in which the conveying portion 16 conveys the printing medium 30 may be a direction parallel to the second direction D2, instead of a direction parallel to the first direction D1 as shown in fig. 2. At this time, the conveying portion 16 can convey the printing medium 30 by the sub-scanning amount between the passage and the passage.

The print medium 30 is not limited to a long medium such as roll paper, and may be cut in advance in page units.