Printing system and method for controlling printer

Abstract

To provide processing corresponding to color information of image data in an ink saving mode.SOLUTION: A printing system 1 includes a printer 2, and an information processing device 10. The printer 2 discharges inks of a plurality of colors including K to a medium M to print an image. The information processing device 10 controls operation of the printer 2. The information processing device 10 executes either one or both of an ink replacement process for increasing a discharge amount of the ink of K and reducing discharge amounts of the inks other than K, and a fading process for fading an image to be printed on a medium M in the case of designating an ink saving mode for reducing discharge amounts of the inks in the printer 2 to perform printing.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Inkjet type printing devices print images by ejecting ink of multiple colors onto a medium. The control device that controls the printing device performs color conversion processing on the color information of the image data using a device profile that corresponds to a color space that depends on the printing device, and creates print data. The print data includes dot data for controlling the amount of ink of each color ejected for each dot that constitutes the image. Printing devices have been proposed that are equipped with an ink-saving mode that reduces ink consumption by, for example, changing the algorithm of the color conversion process (see, for example, Patent Document 1 and Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4471021 [Patent Document 2] JP 2010-74325 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, depending on the color information of the image data, it may not be possible to sufficiently reduce the amount of ink consumption. Therefore, in the ink save mode, it is necessary to provide processing according to the color information of the image data, thereby effectively reducing the amount of ink consumption. In addition to such requirements, another objective of the present invention is to achieve actions and effects derived from the configurations disclosed in the "Form for implementing the invention" described below, which actions and effects cannot be obtained with conventional technologies. [Means for solving the problem]

[0005] One aspect of the present invention is (1) A printing device that prints an image by ejecting ink of a plurality of colors, including black, onto a medium; A printing system including a control device that controls an operation of the printing device, When an ink save mode is specified in which printing is performed by reducing the amount of ink ejected in the printing device, the control device executes either or both of an ink replacement process that increases the amount of black ink ejected and reduces the amount of ink ejected of colors other than black, and a lightening process that lightens the image to be printed on the media.

[0006] (2) In the printing system according to (1), The control device includes: a color conversion unit that converts color information of image data into device values ​​for controlling the ejection amounts of the inks of the plurality of colors by using a device profile corresponding to the printing device; a correction unit that creates an ink replacement profile in which a tertiary color other than black in the device profile is replaced with black when performing the ink replacement process, The color conversion unit performs the color conversion process by using the ink replacement profile instead of the device profile in the ink replacement process.

[0007] (3) In the printing system according to (1) or (2), the device profile includes a first table for converting Lab values ​​independent of the printing device into the device values, and a second table for converting the device values ​​into the Lab values; The correction unit uses the second table to create a list showing the correspondence between the device values ​​and the Lab values, creates a correction list by deleting from the list items that include tertiary or higher colors other than black, extracts from the correction list a plurality of items that have a small color difference with the Lab values ​​of the first table, performs an interpolation calculation using an inverse distance weighting method on the device values ​​of the plurality of items, and creates the ink replacement profile by replacing the results of the interpolation calculation with the device values ​​of the first table.

[0008] (4) In any one of the printing systems (1) to (3), When the lightening process is combined with the ink replacement process, The correction unit is As the lightening process, a color gamut that can be reproduced by the printing device set in the device profile is compressed; As the ink replacement process, a plurality of items having small color differences from Lab values ​​in the color gamut after compression are extracted from the correction list, and the interpolation calculation is performed on device values ​​of the plurality of items.

[0009] (5) In any one of the printing systems (1) to (4), The ink saving mode can specify a level of the ink replacement process, When the level is low, the correction unit processes only device values ​​in the first table that include black, and when the level is high, the correction unit also processes device values ​​in the first table that do not include black.

[0010] (6) In any one of the printing systems (1) to (5), the ink saving mode is capable of specifying a level of the lightening process; The controller causes the image to become more light-toned at the higher levels.

[0011] (7) In any one of the printing systems (1) to (6), As the lightening process, the control device executes either or both of a data process that converts data used to control the operation of the printing device and a physical process that adjusts the volume of ink ejected from the printing device.

[0012] One aspect of the present invention is (8) A method for controlling a printing device that prints an image by ejecting ink of a plurality of colors, including black, onto a medium, comprising the steps of: When an ink save mode is designated in which printing is performed by reducing the amount of ink ejected in the printing device, Either or both of an ink replacement process for increasing the amount of black ink ejected and reducing the amount of ink ejected of colors other than black, and a lightening process for lightening the image to be printed on the medium are executed. Effect of the Invention

[0013] According to the present invention, by providing processing according to color information of image data in the ink save mode, it is possible to effectively reduce the amount of ink consumed. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram illustrating a configuration of a printing system according to an embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing a configuration of a head. [Diagram 3] FIG. 2 is a block diagram showing a functional configuration of the information processing device. [Figure 4] 13A is a diagram illustrating the flow of color conversion processing by the second color conversion unit in normal mode, and FIG. 13B is a diagram illustrating the flow of color conversion processing by the second color conversion unit in ink save mode. [Diagram 5] 11A and 11B are diagrams illustrating examples of settings of an ink saving mode. [Figure 6] FIG. 13 is a diagram showing an example of a CMYK-Lab list. [Figure 7] FIG. 13 is a diagram illustrating an example of an interpolation calculation. [Figure 8]FIG. 13 is a diagram illustrating an example of an interpolation calculation. [Figure 9] 11A and 11B are diagrams illustrating an example of a process in which a lightening process and an ink replacement process are combined. [Figure 10] 4 is a flowchart showing a process of the information processing device. [Figure 11] 11 is a flowchart showing details of the process in step S05 of FIG. 10. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described. FIG. 1 is a schematic diagram showing the configuration of a printing system 1 according to an embodiment. As shown in FIG. 1, the printing system 1 includes a printing device 2 that prints an image by ejecting ink onto a medium M, and an information processing device 10 (control device) that controls the operation of the printing device 2. In the following explanation, the direction from the front side (left side in Fig. 1) to the rear side (right side in Fig. 1) of the printing device 2 is referred to as the "X direction." The direction perpendicular to the X direction, which is the left-right direction of the printing device 2 (the direction from the front side to the back side of the paper in Fig. 1), is referred to as the "Y direction." The direction perpendicular to the X direction, which is the vertical line direction (up-down direction) when the printing device 2 is placed on a horizontal surface, and which is perpendicular to the X and Y directions, is referred to as the "Z direction."

[0016] The printing device 2 according to this embodiment is an inkjet printing device 2 that prints an image by ejecting ink droplets onto a medium M. The medium M is not limited to a specific one, but may be, for example, paper, cloth (woven fabric, nonwoven fabric), or a resin sheet such as polyvinyl chloride or polyester. The image printed on the medium M may include, for example, characters, figures, patterns, colors, and combinations thereof. The ink used in the printing device 2 is not limited to a particular type either, and for example, ultraviolet curable ink, heat curable ink, solvent ink, resin ink, etc. can be used.

[0017] 1, the printing device 2 includes a printing unit 3 and a platen 4. The printing device 2 includes a controller 8 that controls the operation of each unit of the printing device 2.

[0018] The printing unit 3 includes a carriage 32 and a guide rail 33. A head 34 that ejects ink is mounted on the carriage 32. When ultraviolet-curable ink is used in the printing device 2, the carriage 32 may be equipped with an ultraviolet irradiation unit. The guide rail 33 is disposed along the Y direction. The carriage 32 is driven by a driving mechanism (not shown) and is movable in the Y direction along the guide rail 33. As the carriage 32 moves, the head 34 mounted on the carriage 32 also moves in the Y direction. The controller 8 can be mounted, for example, in a housing (not shown) that houses the printing unit 3. The controller 8 can include an operation panel that displays information related to printing to the user and accepts operation inputs from the user.

[0019] The head 34 is provided with a gap between it and the upper surface of the platen 4. Although not shown in Fig. 1, a plurality of nozzles which are ink ejection ports are arranged on the surface of the head 34 facing the platen 4.

[0020] 1, the medium M is supported on the upper surface of the platen 4. When using thermosetting ink, solvent ink, resin ink, or the like in the printing device 2, a heater may be disposed inside the platen 4 to heat or dry the ink ejected onto the medium M. An image is printed on the medium M by ejecting ink from the head 34 while moving the head 34 relatively to the medium M supported by the platen 4.

[0021] The printing device 2 can be, for example, a flatbed machine. In this case, the printing device 2 prints on a sheet-like or board-like medium M placed on a table-like platen 4. Although not shown, the printing device 2 includes a movement mechanism that moves a guide rail 33 in the X direction. The printing device 2 ejects ink at a specified position on the printing surface of the medium M while moving a head 34 mounted on a carriage 32 in the Y direction. The printing device 2 moves the carriage 32 by a distance of one pass using the movement mechanism each time the head 34 makes one reciprocating movement (one pass) in the Y direction.

[0022] The printing device 2 may be, for example, a model that supports a long roll-shaped media M (also called a "vertical machine"). In this case, a sending mechanism (not shown) that transports the media M in the X direction is provided on the rear side of the head 34 of the platen 4. The printing device 2 also includes a pay-out section (not shown) on which the roll-shaped media M is placed on the rear side in the X direction, and a winding section (not shown) that winds up the printed media M in a roll on the front side in the X direction. By driving the sending mechanism, the media M is paid out from the pay-out section and supplied between the platen 4 and the printing section 3. The printing device 2 ejects ink at a specified position on the printing surface of the media M while moving the head 34 mounted on the carriage 32 in the Y direction. The printing device 2, which is a vertical machine, uses the sending mechanism to feed the media M a predetermined distance downstream in the transport direction along the X direction every time the head 34 makes one reciprocating movement (one pass) in the Y direction. This causes an image to be printed on the media M. After printing, the medium M is taken up by the take-up section.

[0023] Fig. 2 is a schematic diagram showing the configuration of the head 34. Fig. 2 shows the head 34 as viewed from below. 2, the head 34 includes a plurality of nozzle portions 341 to 344 aligned in the Y direction. The nozzle portions 341 to 344 are provided on the lower surface of the head 34 (the surface facing the medium M).

[0024] As shown in the enlarged area of ​​Figure 2, each nozzle section is made up of multiple nozzle rows Nq. Each nozzle row Nq is made up of multiple nozzles N arranged at regular intervals in the X direction. These multiple nozzle rows Nq are arranged at intervals in the Y direction to form one nozzle section. Although not shown in the drawing, the head 34 is provided with a piezoelectric element corresponding to each nozzle of the nozzle portions 341 to 344. When the piezoelectric element of each nozzle is driven, ink is ejected from the nozzle.

[0025] The nozzle portions 341 to 344 are each supplied with ink from an ink supply mechanism (not shown). The ink supply mechanism can supply different types of ink to the nozzle portions 341-344 according to the settings of the printing device 2. The inks can be, for example, C (cyan), M (magenta), Y (yellow), and K (black) process color inks (hereinafter referred to as "color inks"). The ink may alternatively be a special ink such as LC (light cyan), LM (light magenta), Gy (gray), W (white), CL (clear), Pr (primer), O (orange), violet, metallic colors (gold, silver), fluorescent colors, etc. In the printing device 2, a variety of colors can be reproduced by discharging and mixing inks of these multiple colors at each dot that constitutes an image.

[0026] In the example of FIG. 2, M (magenta) ink is supplied to nozzle portion 341 of head 34, C (cyan) ink to nozzle portion 342, Y (yellow) ink to nozzle portion 343, and K (black) ink to nozzle portion 344. Note that FIG. 2 is merely an example, and settings such as the number and arrangement of heads, the nozzle portion of each head, the nozzle rows, the number and arrangement of nozzles, and the allocation of ink colors to each nozzle portion can be changed as appropriate. For example, head 34 may include five or more nozzle units. The additional nozzle units may, for example, eject a special color ink, or may eject an ink of a color that is consumed in large quantities among color inks (e.g., black). Alternatively, a head separate from head 34 may be provided. In the additional head as well, the type of ink ejected from each nozzle unit can be set as appropriate.

[0027] The controller 8 can be configured, for example, from a microcomputer equipped with a processor and a memory. The controller 8 is communicatively connected to the information processing device 10 via a LAN cable or the like. The controller 8 receives print data for controlling the operation of the printing device 2 from the information processing device 10. The controller 8 controls operations such as the movement of the carriage 32 by the drive mechanism and the ejection of ink from the head 34 based on the print data.

[0028] FIG. 3 is a block diagram showing the functional configuration of the information processing device 10. As shown in FIG. The information processing device 10 may be a general-purpose information processing device 10 such as a personal computer, a mobile phone, or a tablet terminal. Although not shown in the figure, the information processing device 10 includes a processor such as a CPU (Central Processing Unit) and memories such as an HDD (Hard Disk Drive), an SSD (Solid State Drive), and a RAM (Random Access Memory). Various software required for the operation of the information processing device 10 is installed in the memory. As an example, software (image creation software) for creating and editing data (image data) of an image to be printed by a printer and software (software RIP: Raster Image Processor) for creating print data based on the image data are installed in the memory. That is, the information processing device 10 functions as an image processing device that creates image data to be printed on the medium M. The information processing device 10 also functions as a control device that controls the operation of the printing device 2 by transmitting the created print data to the printing device 2. The memory of the information processing device 10 also stores various data required for creating image data and print data.

[0029] The information processing device 10 also includes a display device such as a liquid crystal display, and an input device such as a mouse, a keyboard, a touch panel, etc. The information processing device 10 displays an operation screen for creating image data and print data on the display device, and accepts operation input from the user via the input device.

[0030] As shown in FIG. 3, the information processing device 10 includes an image data creating section 11, a job management section 12, and a print data creating section 13 as functional components. The image data creation unit 11 creates image data to be printed by a printer on a medium M in response to an operational input by a user. The created image data is stored in the memory of the information processing device 10. The image data expresses color information of an image in any color system that is independent of the printing device 2, such as the RGB color system or the CMYK color system.

[0031] The user uploads image data to be printed on the medium M via an operation screen provided by the software of the information processing device 10. Note that the image data to be uploaded is not limited to that created by the image data creation unit 11, and may be that created by another information processing device 10. The job management unit 12 creates print jobs based on image data uploaded by the user and registers them in a job list. The job management unit 12 manages the progress of each print job registered in the job list, and reflects the progress of printing in the job list. When a user selects a print job to be executed from the job list and inputs an instruction to start printing, the job management unit 12 outputs image data of the specified print job to the print data creation unit 13, causing it to create print data for controlling the operation of the printing device 2. The job management unit 12 sends the created print data to the controller 8 of the printing device 2, causing it to start printing. When the job management unit 12 receives a notification from the controller 8 that printing is complete, it updates the job list and deletes the completed print job.

[0032] A user can specify various printing conditions via an operation screen when uploading image data or inputting a command to start printing. The job management unit 12 outputs the specified printing conditions together with the image data to the print data creation unit 13. The print data creation unit 13 creates print data according to the printing conditions. In this embodiment, an ink-save mode is set as one of the printing conditions that can be specified by the user. The ink-save mode is a printing mode in which printing is performed with less ink consumption than normal printing.

[0033] The print data created by the print data creation unit 13 includes dot data for controlling the amount of ink of each color ejected for each dot that constitutes an image. As described above, in the image data, the color information of the image is expressed in the RGB color system or the CMYK color system, etc., which are independent of the printing device 2. In order to create dot data, the print data creation unit 13 performs a color conversion process that converts the color information of the image data into device values, which are color information that are dependent on the printing device 2.

[0034] As shown in FIG. 3, the print data creation unit 13 includes a first color conversion unit 14, a second color conversion unit 15, a dot data creation unit 16, and a correction unit 17. The first color conversion unit 14 performs color conversion processing (first color conversion processing) on ​​the color information of the image data expressed in the RGB color system or the CMYK color system, etc., using an input profile (hereinafter referred to as "input PF") corresponding to the L*a*b* color space. Hereinafter, "L*a*b*" will simply be referred to as "Lab." Through the color conversion processing of the first color conversion unit 14, the color information of the image data is converted into device-independent Lab values.

[0035] FIG. 4(a) is a diagram illustrating the flow of color conversion processing by second color conversion unit 15 in the normal mode. As shown in FIG. 4(a), second color conversion unit 15 performs color conversion processing (second color conversion processing) on ​​the Lab values ​​converted by first color conversion unit 14, using a device profile (device PF). The device PF associates Lab values, which indicate a color space independent of a device, with device values, which indicate a color space dependent on a device (printing device 2). As described above, in this embodiment, an example is described in which the printing device 2 ejects CMYK inks. Therefore, in the following description, device values ​​will be referred to as "CMYK values." The device PF includes a lookup table (hereinafter referred to as "LUT1") for converting Lab values ​​into CMYK values, and an LUT2 for converting CMYK values ​​into Lab values. The LUT1 is a table that records the CMYK values ​​required to reproduce a given Lab value on the printing device 2. LUT2 is a table that records what colors (Lab values) will be reproduced when printing is performed with the printing device 2 using predetermined CMYK values. The second color conversion unit 15 performs color conversion processing (second color conversion processing) by referring to LUT1 of the device PF and acquiring CMYK values ​​corresponding to the Lab values ​​converted by the first color conversion unit 14. Note that, if the printing device 2 ejects special color inks, such as light colors and orange colors, in addition to CMYK, the device PF may use one that corresponds to a color space that includes these colors in addition to CMYK.

[0036] The dot data creation unit 16 (see FIG. 3) creates dot data by performing halftone processing, rasterization processing, etc. on the CMYK values ​​acquired in the color conversion processing of the second color conversion unit 15. The dot data creation unit 16 further adds various commands according to the printing conditions to the created dot data, and outputs it to the job management unit 12 as the final print data.

[0037] As described above, in this embodiment, the ink-save mode can be set as a printing condition. When the ink-save mode is specified as a printing condition, the print data creation unit 13 performs processing to reduce ink consumption compared to the normal mode when creating print data. In the ink-save mode, the print data creation unit 13 can perform two types of processing, ink replacement processing and color lightening processing, either alone or in combination. FIG. 5 is a diagram showing an example of the setting of the ink save mode. 5, in the ink save mode, the print data creation unit 13 performs two types of processing: ink replacement processing and color lightening processing. The ink replacement processing is processing for increasing the amount of K (black) ink ejected in the printing device 2, and reducing the amount of ink ejected of colors other than K. The color lightening processing is processing for lightening the color of the image to be printed on the medium M. Furthermore, the ink saving mode can be set to a number of levels (for example, levels 1 to 5). The higher the level, the greater the reduction in ink consumption. The user can set an appropriate level, taking into consideration the priority between image print quality and reducing ink consumption. <Ink replacement process> FIG. 4B is a diagram illustrating the flow of color conversion processing by the second color converter 15 in the ink replacement processing. 4(b), in the ink replacement process, the second color conversion unit 15 performs color conversion processing using an ink replacement profile (hereinafter, referred to as "ink replacement PF") instead of the device PF described above. In the ink replacement PF, the CMYK values ​​in the LUT1 of the device PF are replaced with C'M'Y'K' values ​​that can reduce ink consumption. 4(a) and 4(b), the C'M'Y'K' values ​​replace CMY in the CMYK values ​​acquired in normal mode with K. As a result, the printing device 2 operates based on dot data created using the C'M'Y'K' values, and while the ink ejection amount of K (black) increases, the ink ejection amount of colors other than K (for example, CMY) decreases, resulting in a reduction in the overall ink consumption.

[0038] The ink replacement PF is created by the correction unit 17 (see FIG. 3) of the print data creation unit 13. To create the ink replacement PF, the correction unit 17 creates a CMYK-Lab list, which is a correction list, using LUT2 of the device PF. The correction unit 17 further performs an interpolation calculation using the CMYK-Lab list to calculate C'M'Y'K' values, which are correction values ​​of the CMYK values ​​of LUT1 of the device PF. The correction unit 17 creates the ink replacement PF by rewriting each CMYK value of LUT1 to a C'M'Y'K' value.

[0039] FIG. 6 is a diagram showing an example of the CMYK-Lab list. As shown in FIG. 6, the CMYK-Lab list is obtained by removing items including tertiary or higher colors other than K from a list showing the correspondence between Lab values ​​and CMYK values. The correction unit 17 first creates a list of combinations for each predetermined increment of the CMYK values. In Fig. 6, the increment is set to 10, but the increment is not limited to a specific number and can be changed as appropriate. The correction unit 17 then performs color conversion processing to convert the CMYK values ​​of each item in the list into Lab values ​​using LUT2 of the device PF, and records the obtained Lab values ​​in each item of the CMYK list. The correction unit 17 deletes items including tertiary colors (CMY) other than K from the list, and stores the list in memory as a CMYK-Lab list.

[0040] The correction unit 17 uses the created CMYK-Lab list to perform an interpolation calculation by the inverse distance weighting method to calculate C'M'Y'K' values ​​by correcting each CMYK value described in LUT1 of the device PF. 7 and 8 are diagrams for explaining an example of the interpolation calculation. (a) of Figure 7 shows an example of the CMYK values ​​to be corrected (hereinafter referred to as "target CMYK values") and the Lab values ​​corresponding to the target CMYK values ​​(hereinafter referred to as "target Lab values") written in LUT1. The correction unit 17 refers to the CMYK-Lab list and extracts a plurality of items that describe Lab values ​​(hereinafter, referred to as "approximate Lab values") that have small color differences from the target Lab values. In (b) of Fig. 7, the extracted items are shown in order of the smallest color difference (ΔE) between the approximate Lab value and the target Lab value. Note that, although (b) of Fig. 7 shows 10 items (No. 1 to 10), the number of items to be extracted is not limited to 10 and can be set appropriately.

[0041] The correction unit 17 calculates the inverse distance between each of the extracted approximate Lab values ​​and the target Lab value by using the following formula (1). Inverse Distance=(1 / ΔE) 2 (1)

[0042] The correction unit 17 calculates the weight to be assigned to each point by dividing the inverse distance of each approximate Lab value by the sum of the inverse distances of the 10 points, as shown in the following formula (2). Weight = Inverse Distance / SUM(Inverse Distance) (2)

[0043] The correction unit 17 calculates the result of the interpolation calculation (interpolation result) by multiplying the CMYK value of each point by a weight. FIG. 8 shows the interpolation results for each of the 10 points and the total value of the interpolation results for the 10 points. The correction unit 17 uses the calculated total C'M'Y'K' value of the interpolation results for each point as a correction value for the target CMYK value. As shown in the example of Figure 8, the C'M'Y'K' values ​​(96.44, 3.10, 7.90, 25.07) obtained by the interpolation calculation have K increasing but CMY decreasing compared to the target CMYK values ​​(C: 93.67, M: 34.12, Y: 22.13, K: 2.94). On the other hand, the total C'M'Y'K' values ​​T (132.51) is smaller (T) than the total target CMYK values ​​T0 (152.86, see Figure 7(a)). <T0)。 Therefore, when the dot data creation unit 16 creates dot data to control the printing device 2 using C'M'Y'K' values, compared to the target CMYK values, the amount of K ink ejected is increased but the amount of CMY ink ejected is reduced, and the overall ink consumption is reduced.

[0044] The correction unit 17 replaces each target CMYK value written in LUT1 of the device PF with the C'M'Y'K' value resulting from the interpolation. The correction unit 17 stores the device PF in which LUT1 has been rewritten in memory as an ink replacement PF. In addition, if the total T of the C'M'Y'K' values ​​is greater than or equal to the total T0 of the target CMYK values, the overall ink consumption will not be reduced, so the correction unit 17 may maintain the original target CMYK values ​​without performing replacement.

[0045] As shown in the setting example of Fig. 5, the ink replacement process may be set to be performed from level 1 of the ink save mode. Furthermore, the content of the ink replacement process may be changed depending on the level. For example, at level 1, the correction unit 17 may perform an interpolation calculation on only the CMYK values ​​containing K in LUT1 as the target CMYK values ​​to be corrected. In other words, the interpolation calculation is not performed on the CMYK values ​​in LUT1 where K is 0, and the original CMYK values ​​are maintained in the ink replacement PF. For example, in levels 2 to 5, the correction unit 17 may also perform interpolation calculations on CMYK values ​​where K is 0 as target CMYK values ​​to be corrected. This allows the ink replacement process in levels 2 to 5 to significantly reduce ink consumption compared to level 1. Note that, for CMYK values ​​in LUT1 that contain only the primary or secondary colors of CMY, there is no room for replacement with K, so they are not subject to correction even in levels 2 to 5.

[0046] <Lightening process> In the lightening process, the information processing device 10 lightens the colors of the image to be printed on the medium M, thereby reducing the amount of ink consumed. As previously mentioned, the lightening process may be performed alone or in combination with the ink replacement process described above. 5, the lightening process can be set not to be performed at levels 1 and 2 of the ink saving mode, but to be performed in combination with the ink replacement process at levels 3 to 5. The lightening process can also be set so that the degree of lightening increases with each increase in level.

[0047] The color lightening process can be considered to be a process having two aspects, for example, in terms of "lightening the color expression" of the image printed by the printing device 2. One aspect is a process on data, and the other aspect is a physical process. Data processing means converting data to be used for printing, and the data to be converted is, for example, any data to be used for printing, such as image data or print data. Data processing can be performed, for example, by the image data creation unit 11 or the print data creation unit 13 (see FIG. 3) when creating the respective data. On the other hand, physical processing means directly adjusting the volume of ink ejected from the head 34 of the printing device 2. For example, the physical processing can be performed by the dot data creation unit 16 (see FIG. 3) creating print data and then processing the data as printing condition settings when printing is performed using the printing device 2. Note that the physical processing may also be performed by the correction unit 17.

[0048] Either the data processing or the physical processing may be performed in combination with the ink replacement processing described above in the ink save mode, or may be performed alone. Also, as the lightening processing, either the data processing or the physical processing may be performed alone, or a combination of both may be performed.

[0049] As a data processing, for example, the brightness and saturation of the image data can be adjusted in advance. The brightness and saturation of the image data can be adjusted, for example, automatically by the image data creation unit 11, or according to a user's operation input. The user can adjust the brightness and saturation while checking how much the color will be lightened from the original image data, for example, via an operation screen provided by the software of the information processing device 10. In this processing, the brightness and saturation of the original image are adjusted overall, so that the entire image can be lightened evenly.

[0050] Furthermore, as a data processing step, the dot data creation unit 16 (see FIG. 3) can apply a mask for thinning out the ink ejection after halftone processing, rasterization processing, or the like, or simultaneously with these processing, to the CMYK values ​​acquired in the color conversion processing of the second color conversion unit 15. Thinning out the ink ejection means that ink dots that would normally be ejected in the halftone processing or rasterization processing are ejected at a predetermined interval.

[0051] As a data processing step, it is also possible to reduce the range of colors that can be reproduced by the printing device 2 (see FIG. 1). Reducing the range of reproducible colors means compressing the color gamut set in the device PF. This processing can be performed by, for example, the correction unit 17. For example, the correction unit 17 can compress the color gamut by reducing the boundaries in the reproducible color range by a predetermined distance from the center of the color gamut. By compressing the range of colors (color gamut) that can be reproduced by the printing device 2, the correction unit 17 converts the Lab values ​​that make up the color gamut into L'a'b' values.

[0052] As a physical process, for example, the maximum amount of ink ejected from the head 34 can be limited (an ink limit can be set) on the software RIP. For example, if the maximum amount of ink ejected is set to 100%, the ink limit can be set by limiting the maximum amount of ink ejected to 80%. The ink limit can be set at any interval from the maximum amount of ink ejected of 100%. As a physical process, for example, the volume of an ink droplet per dot can be adjusted. Since the volume of an ink droplet can be adjusted by the drive waveform, a drive waveform for the lightening process is set so that the volume of an ink droplet is reduced at a predetermined ratio and ejected separately from the drive waveform for the normal mode. In addition, as a physical process, if variable dots using large (Large, L) dots, medium (M) dots, and small (S) dots are available, it is possible to set it so that L dots are converted to M dots and M dots are converted to S dots and then ejected.

[0053] As shown in Fig. 5, the lightening process can be combined with the ink replacement process and set so that the image becomes more lightened as the ink save mode level becomes higher. For example, each lightening process may be set so that the lightening progresses as the level becomes higher. For example, when the correction unit 17 compresses the color gamut as the lightening process, the compression rate may be set so that the compression rate increases as the level becomes higher. Alternatively, the higher the level, the more lightening processes may be combined. For example, at low levels, only data processing or physical processing may be performed, and at higher levels, both types of processing may be combined.

[0054] FIG. 9 is a diagram for explaining a processing example in which the lightening process and the ink replacement process are combined. As shown in (a) of Fig. 9, as a lightening process, for example, the image data creation unit 11 (see Fig. 3) can adjust the lightness or saturation of the image data. The first color conversion unit 14 (see Fig. 3) converts the color information of the image data that has been subjected to the lightening process into Lab values ​​using an input PF. When combined with the ink replacement process, the second color conversion unit 15 (see Fig. 3) performs a color conversion process using the ink replacement PF. This makes it possible to convert to C'M'Y'K' values ​​with further reduced ink usage.

[0055] As shown in Fig. 9(b), as the lightening process, for example, the dot data creation unit 16 (see Fig. 3) can perform the above-mentioned data processing or physical processing when creating print data. When combined with the ink replacement process, the dot data creation unit 16 creates dot data using the C'M'Y'K' values ​​converted by the second color conversion unit 15 (see Fig. 3) using the ink replacement PF, and also performs the lightening process.

[0056] As shown in (c) of Fig. 9, as the lightening process, for example, the correction unit 17 (see Fig. 3) can compress the color gamut set in the device PF and convert the Lab values ​​constituting the color gamut into L'a'b' values. When combined with the ink replacement process, the correction unit 17 performs an interpolation calculation using the L'a'b values ​​acquired in the lightening process to create the ink replacement PF. The correction unit 17 performs the above-mentioned interpolation calculation process using the compressed L'a'b' value as a target Lab value in the interpolation calculation. The correction unit 17 refers to the CMYK-Lab list and extracts an approximate Lab value having a small color difference ΔE with the L'a'b' value. The correction unit 17 calculates the inverse distance between the approximate Lab value and the L'a'b' value, calculates a weight from the inverse distance, and multiplies the CMYK value of each point by the weight to calculate the interpolation result. The correction unit 17 creates an ink replacement PF by replacing the CMYK value of LUT1 with the total value C'M'Y'K' of the interpolation result of each point. The second color conversion unit 15 (see FIG. 3) performs color conversion process using the ink replacement PF, thereby enabling conversion to a C'M'Y'K' value with a further reduced amount of ink used.

[0057] As described above, the ink replacement process reduces the overall ink consumption by replacing the CMY device values ​​with K. Therefore, the ink replacement process is particularly effective in reducing ink consumption when printing images with many dots that include tertiary or higher colors of CMY. On the other hand, in the case of pure CMYK colors and secondary colors, the amount of ink reduction may be small. In the lightening process, the entire image is lightened, so ink consumption can be effectively reduced even when printing an image with many dots of pure CMY colors or secondary colors. Furthermore, if an attempt is made to significantly reduce ink consumption by using only lightening processing, the entire image will end up being lighter in color. By combining lightening processing with ink replacement processing, it is possible to effectively reduce ink consumption while preventing the entire image from becoming lighter. In this manner, in this embodiment, by combining the ink replacement process and the color lightening process, it is possible to appropriately reduce the amount of ink consumption according to the colors contained in the image.

[0058] In this embodiment, the ink replacement process and the color lightening process may be performed separately depending on the level setting of the ink save mode. Also, the process contents of the ink replacement process and the color lightening process can be set so that the amount of ink consumed increases depending on the level. This makes it possible to provide the user with a variety of ink save mode variations according to the priority of print quality and ink consumption.

[0059] FIG. 10 is a flowchart showing the process of the information processing device 10. In addition, Fig. 10 describes the process from a state where a user inputs an instruction to start a print job registered in a job list. In addition, in Fig. 10, the process is described according to the example of setting the ink save mode in Fig. 5. As described above, the color lightening process includes various processing modes, but in Fig. 10, as an example, the case where the correction unit 17 compresses the color gamut is described.

[0060] The job management unit 12 inputs the image data and printing conditions of the print job to the print data creation unit 13 (step S01). The print data creation unit 13 refers to the input printing conditions, and if the ink save mode is not specified (step S02: No), the process proceeds to step S06.

[0061] If the ink saving mode is specified in the printing conditions (step S02: Yes) and the level of the ink saving mode is level 1 to 2 (step S03: Yes), the lightening process is not performed and only the ink replacement process is performed. The print data creation unit 13 proceeds to step S05. If the ink save mode is specified in the printing conditions (step S02: Yes) and the ink save mode level is level 3 to 5 (step S03: No), both the lightening process and the ink replacement process are performed. The print data creation unit 13 proceeds to step S04. In step S04, the correction unit 17 of the print data creation unit 13 compresses the color gamut of the device PF as an example of a lightening process to obtain L'a'b' values. At this time, the correction unit 17 can set a compression ratio according to the level of the ink saving mode. In step S05, the correction unit 17 of the print data creation unit 13 creates the ink replacement PF using the device PF. Note that if the process of step S04 has been performed, the correction unit 17 creates the ink replacement PF using the L'a'b' values.

[0062] FIG. 11 is a flowchart showing details of the process in step S05 of FIG. As shown in FIG. 11, the correction unit 17 uses LUT2 of the device PF to create a list showing the correspondence between CMYK values ​​and Lab values, and deletes items including tertiary colors (CMY) other than K from the list to create a CMYK-Lab list (step S51). In the case of level 1 of the ink save mode (step S52: Yes), the correction unit 17 sets the CMYK values ​​containing K in LUT1 as the target CMYK values ​​to be corrected (step S53). In the case of levels 2 to 5 of the ink save mode (step S52: No), the correction unit 17 sets not only the CMYK values ​​containing K in LUT1 but also the CMYK values ​​where K is 0 as the target CMYK values ​​to be corrected (step S54).

[0063] The correction unit 17 acquires the Lab values ​​(target Lab values) corresponding to the target CMYK values ​​from the LUT1 of the device PF (step S55). Here, when the compression process of the gamut GM is performed in step S04 of Fig. 10, the correction unit 17 uses the L'a'b' values ​​acquired in the compression process as the target Lab values. The correction unit 17 refers to the CMYK-Lab list and extracts a plurality of items including an approximate Lab value having a small color difference ΔE from the target Lab value (step S56). The correction unit 17 calculates the inverse distance between the target Lab value and the approximate Lab value of each point, and calculates the weight to be assigned to each point (step S57). The correction unit 17 multiplies the CMYK value of each point by the weight to calculate an interpolation result, and calculates a C'M'Y'K' value that is the sum of the interpolation results (step S58). The correction unit 17 creates an ink replacement PF by replacing the target CMYK value of LUT1 with the interpolation result C'M'Y'K' value (step S59).

[0064] As shown in FIG. 10, the first color conversion unit 14 uses the input PF to perform color conversion processing on the color information (RGB, etc.) of the image data input from the job management unit 12, and converts it into device-independent Lab values ​​(step S06). The second color conversion unit 15 performs color conversion processing on the Lab values ​​of each dot obtained by the first color conversion unit 14 (step S07), converting them into CMYK values. In the normal mode, the second color conversion unit 15 performs color conversion processing using a device PF to obtain the CMYK values. In the ink save mode, the second color conversion unit 15 performs color conversion processing using an ink replacement PF to obtain the C'M'Y'K' values.

[0065] The dot data creation unit 16 creates dot data using the CMYK values ​​or C'M'Y'K' values ​​of each dot constituting the image acquired by the second color conversion unit 15 (step S08), and adds other necessary commands to create print data (step S09). The job management unit 12 transmits the created print data to the printer 2 (step S10). It should be noted that the processes shown in the flowcharts of Figures 10 and 11 are merely examples. As described above, the lightening process can be carried out in various ways. For example, if the lightening process involves adjusting the brightness or saturation of the image data, the lightening process can be carried out in the image data creation unit 11 before uploading the image data to the job list. Also, for example, if the dot data creation unit 16 carries out the lightening process, the lightening process can be carried out when creating the print data in step S09.

[0066] As described above, the printing system 1 described in the embodiment has, for example, the following configuration. (1) The printing system 1 includes a printing device 2 and an information processing device 10 (control device). The printing device 2 ejects ink of a plurality of colors, including K (black), onto the medium M to print an image. The information processing device 10 controls the operation of the printing device 2 . When an ink save mode is specified in which printing is performed by reducing the amount of ink ejected in the printing device 2, the information processing device 10 executes either or both of an ink replacement process that increases the amount of K (black) ink ejected and instead reduces the amount of ink ejected of colors other than K, and a lightening process that lightens the image to be printed on the medium M.

[0067] In this embodiment, by providing processing according to the color information of the image data in the ink save mode, it is possible to effectively reduce the amount of ink consumed. In the ink saving mode, the printing system 1 of this embodiment can execute two types of processing: ink replacement processing and color lightening processing. The ink replacement process increases the amount of K (black) ink ejected, and instead reduces the amount of ink ejected of colors other than K, and is particularly effective in reducing ink consumption when the color information of the image data includes tertiary colors of CMY. On the other hand, the lightening process lightens the entire image printed on the medium M, so ink consumption can also be reduced for pure colors and secondary colors. Users can effectively reduce ink consumption by performing these processes alone or in combination, taking into consideration the color of the image to be printed on the medium M, the required print quality, and the priority of reducing ink consumption.

[0068] (2) The information processing device 10 a first color conversion unit 14 and a second color conversion unit 15 (color conversion units) that convert color information of image data into CMYK values ​​(device values) for controlling the ejection amounts of ink of multiple colors using a device PF (device profile) corresponding to the printing device 2; The printer includes a correction unit 17 that creates an ink replacement PF (ink replacement profile) in which tertiary colors of CMY (other than K) in the device PF are replaced with K when performing ink replacement processing. In the ink replacement process, the second color conversion unit 15 performs color conversion processing by using an ink replacement PF instead of a device PF.

[0069] In the ink-save mode, for example, it is possible to perform color conversion processing using a device PF different from that in the normal mode. In this case, however, it is necessary to separately create a device PF for the ink-save mode using a profiler and load it into the information processing device 10. This may result in cumbersome processing. In this embodiment, when performing ink replacement processing, the information processing device 10 can automatically create an ink replacement PF based on the device PF used in the normal mode. This eliminates the need to load a device PF for the ink-save mode into the information processing device 10, making it possible to simplify processing.

[0070] (3) The device PF includes an LUT1 (first table) for converting Lab values ​​that are independent of the printing device 2 into CMYK device values, and an LUT2 (second table) for converting device values ​​into Lab values. The correction unit 17 uses LUT2 to create a list that lists Lab values ​​corresponding to each color combination of CMYK values ​​(device values), and creates a CMYK-Lab list (list for correction) by deleting items that include tertiary or higher colors of CMYK (other than K) from the list. The correction unit 17 extracts multiple items from the CMYK-Lab list that have a small color difference ΔE from the target Lab value of LUT1, and performs an interpolation calculation using the inverse distance weighting method on the approximate CMYK values ​​(device values) of the multiple items. The correction unit 17 creates an ink replacement PF by replacing the C'M'Y'K' values, which are the results of the interpolation (result of the interpolation calculation), with the target CMYK values ​​(device values) of LUT1.

[0071] When multiple items including approximate Lab values ​​with small color difference ΔE from the target Lab value are extracted from the CMYK-Lab list, the CMYK values ​​(approximate CMYK values) listed in those items have in common that they do not include tertiary colors of CMY, but otherwise have different numerical variations. The correction unit 17 performs an interpolation calculation using these approximate CMYK values ​​by the inverse distance weighting method, thereby reducing CMY and calculating a color close to the target CMYK value.

[0072] (4) When the color lightening process is combined with the ink replacement process, the correction unit 17 compresses the color gamut reproducible by the printing device 2 set in the device profile, as an example of the color lightening process. As an ink replacement process, the correction unit 17 also extracts from the CMYK-Lab list multiple items having small color difference ΔE with the L'a'b' values ​​in the color gamut after compression, and performs an interpolation calculation on the CMYK values ​​of the multiple items.

[0073] In this way, as an example of a combination of ink replacement processing and color lightening processing, an ink replacement PF can be created using the L'a'b' values ​​acquired in the color lightening processing. The second color conversion unit 15 performs color conversion processing using the ink replacement PF created in this way, thereby acquiring C'M'Y'K' values ​​with further reduced ink consumption. In addition, since both the ink replacement processing and the color lightening processing can be performed in one ink replacement PF, the processing can be simplified.

[0074] (5) The ink saving mode allows the user to specify the level of ink replacement processing. When the level is low (for example, level 1 in FIG. 5), the correction unit 17 corrects (processes) only the CMYK values ​​in LUT1 that include K. When the level is high (for example, levels 2 to 5 in FIG. 5), the correction unit 17 also corrects the CMYK values ​​in LUT1 that do not include K.

[0075] As a result, the higher the level of the ink saving mode, the greater the reduction in ink consumption. A user can set an appropriate level, taking into consideration the priority between image print quality and reduction in ink consumption.

[0076] (6) The ink saving mode allows the user to specify the level of lightening processing. The information processing device 10 performs processing so that the higher the level, the more the image becomes lighter in color.

[0077] As a result, the higher the level of the ink saving mode, the greater the reduction in ink consumption. The user can set an appropriate level, taking into consideration the priority between image print quality and reduction in ink consumption. As described above, the ink replacement process and the color lightening process can be performed alone or in combination, but by setting multiple levels for each process, even more diverse ink saving mode aspects can be provided, improving user convenience.

[0078] (7) As a lightening process, the information processing device 10 can execute either or both of the following: data processing to convert data (image data, print data, etc.) used to control the operation of the printing device 2, and physical processing to adjust the volume of ink ejected from the printing device 2.

[0079] As described above, a variety of processes can be performed as the lightening process, and by performing these processes alone or in combination, a variety of ink saving mode configurations can be provided, thereby improving user convenience.

[0080] The above-mentioned effects can also be applied to the control method of the printing device 2.

[0081] The present invention is not limited to the above-described embodiment and modified examples, and can be modified as appropriate within the scope of the technical concept of the present invention.

[0082] For example, the function of the print data creation unit 13 of the information processing device 10 may be realized in the controller 8 of the printing device 2. That is, the controller 8 of the printing device 2 can also function as a control device for the printing system 1.

[0083] For example, as described above, the printing device 2 may eject special color inks such as light colors (LM, LC, LK), orange (Or), and green (G) in addition to the process colors of CMYK. For example, when the printing device 2 ejects Or, the device PF used in the second color conversion unit 15 may be one that corresponds to a color space including CMYKOr. In this case, in the ink replacement process, not only the tertiary color of CMY is replaced with K, but also the secondary color of MY may be replaced with Or. Specifically, when the correction unit 17 creates a CMYK Or-Lab list (correction list) using LUT2 of the device PF, it deletes items including secondary colors of MY in addition to tertiary colors of CMY. In this way, by appropriately changing the settings for replacing tertiary colors and secondary colors in the ink replacement process depending on the hue of the ink used in the printing device 2, it is possible to reduce the overall amount of ink consumption. For example, if the hue of the printing device 2 includes green (G), then when creating the correction list, it is possible to delete items that include the secondary color of CY. For example, if the hue of the printing device 2 includes blue (B), then when creating the correction list, it is possible to delete items that include the secondary color of CM. For example, if the hue of the printing device 2 includes red (R), then when creating the correction list, it is possible to delete items that include the secondary color of MY. If it is not possible to create a device PF that supports a color space that includes spot color inks, conversion may be performed by setting the ratio of CMYK process colors and spot color inks for each color. In this case, since the color tone may vary depending on the printing device 2, the ratio may be determined by measuring the color of the image printed on the medium M. [Explanation of symbols]

[0084] 1 Printing System 2 Printing device 10 Information processing device (control device) 13 Print data creation section 14 First color conversion unit (color conversion unit) 15 Second color conversion unit (color conversion unit) 16 Dot Data Creation Section 17 Correction section

Claims

1. A printing device that prints an image by ejecting ink of a plurality of colors, including black, onto a medium; A printing system including a control device that controls an operation of the printing device, The control device, when an ink save mode is specified in which printing is performed by reducing the amount of ink ejected in the printing device, executes either or both of an ink replacement process that increases the amount of black ink ejected and reduces the amount of ink ejected of colors other than black, and a lightening process that lightens the image to be printed on the media.

2. In claim 1, The control device includes: a color conversion unit that converts color information of image data into device values ​​for controlling the ejection amounts of the inks of the plurality of colors by using a device profile corresponding to the printing device; a correction unit that creates an ink replacement profile in which a tertiary color other than black in the device profile is replaced with black when performing the ink replacement process, The color conversion unit performs color conversion processing by using the ink replacement profile instead of the device profile in the ink replacement processing.

3. In claim 2, the device profile includes a first table for converting Lab values ​​independent of the printing device into the device values, and a second table for converting the device values ​​into the Lab values; the correction unit uses the second table to create a list indicating the correspondence between the device values ​​and the Lab values, creates a correction list by deleting from the list items including tertiary or higher colors other than black, extracts from the correction list a plurality of items having small color differences with the Lab values ​​of the first table, performs an interpolation calculation using an inverse distance weighting method on the device values ​​of the plurality of items, and creates the ink replacement profile by replacing the device values ​​of the first table with the results of the interpolation calculation.

4. In claim 3, When the lightening process is combined with the ink replacement process, The correction unit is As the lightening process, a color gamut that can be reproduced by the printing device set in the device profile is compressed; The printing system includes extracting, as the ink replacement process, from the correction list, a plurality of items having small color differences from Lab values ​​in the color gamut after compression, and performing the interpolation calculation on device values ​​of the plurality of items.

5. In claim 3, The ink saving mode can specify a level of the ink replacement process, A printing system in which, when the level is low, the correction unit processes only device values ​​in the first table that include black, and, when the level is high, the correction unit also processes device values ​​in the first table that do not include black. Printing system.

6. In any one of claims 1 to 5, the ink saving mode is capable of specifying a level of the lightening process; The controller causes the image to become lighter the higher the level.

7. In any one of claims 1 to 5, A printing system in which the control device performs, as the lightening process, either or both of a data process that converts data used to control the operation of the printing device and a physical process that adjusts the volume of ink ejected from the printing device.

8. A method for controlling a printing device that prints an image by ejecting ink of a plurality of colors, including black, onto a medium, comprising the steps of: When an ink save mode is designated in which printing is performed by reducing the amount of ink ejected in the printing device, A control method for a printing device, which executes either or both of an ink replacement process that increases the amount of black ink ejected and reduces the amount of ink ejected of colors other than black, and a lightening process that lightens the image to be printed on the media.

Images