JP2020157586A - Image processor, and computer program - Google Patents

Abstract

To suppress color unevenness in an image printed by bidirectional printing.SOLUTION: An image processor stores one profile for a first direction corresponding to the first direction along a main scanning direction, and plural profiles for a second direction corresponding to the second direction opposite to the first direction. The image processor selects the profile for the second direction to be used from the plural profiles for the second direction, and generates plural partial print data, which include first partial print data for partial printing performed in the first direction and second partial print data for partial printing performed in the second direction, by use of object image data. The image processor executes first generation processing including first color conversion processing executed by use of the profile for the first direction to generate first partial print data, and executes second generation processing including second color conversion processing executed by use of the profile for the second direction selected from the plural profiles for the second direction to generate second partial print data.SELECTED DRAWING: Figure 7

Description

The present specification relates to image processing for a print execution unit that prints by executing partial printing and sub-scanning that form dots while performing main scanning a plurality of times.

There is known a printing system that performs bidirectional printing by combining outbound printing performed in the outbound route of the main scan and inbound print performed in the inbound route of the main scan. In Patent Document 1, when color unevenness is likely to occur in bidirectional printing, the first conversion table is used when creating print data to be used in outbound printing, and print data to be used in inbound printing. A technique for using a second conversion table is disclosed in creating the above. These techniques are used to improve the image quality of images printed by bidirectional printing.

Japanese Unexamined Patent Publication No. 2005-342962

However, in the above technique, the print data is only generated by using the pair of the first conversion table and the second conversion table. For this reason, when the degree of color unevenness fluctuates due to printing conditions, etc., in the image printed by bidirectional printing, between the part printed by outbound printing and the part printed by inbound printing. There was a possibility that color unevenness would be noticeable.

The present specification discloses a technique capable of suppressing color unevenness of an image printed by bidirectional printing.

The techniques disclosed herein can be realized as the following application examples.

[Application Example 1] A first-class nozzle that ejects first-class ink and a second-class nozzle that ejects second-class ink have different positions in the main scanning direction from the first-class nozzle. A print head having the above, a main scanning unit that executes a main scan for moving the print head along the main scanning direction with respect to the print medium, and a sub-scan that intersects the main scanning direction with respect to the print head. A printing execution unit including a sub-scanning unit that executes a sub-scanning that moves the printing medium in a direction, and partial printing that forms dots on the printing medium by the printing head while performing the main scanning, and the above-mentioned An image processing device for the print execution unit that prints by executing sub-scanning a plurality of times, and is a first-class color value, the first-class ink, and the second-class ink. A storage unit for storing a plurality of profiles that define a correspondence relationship between a second type color value including a component value corresponding to a plurality of types of inks including, and the plurality of profiles are the main scan. The storage unit including one first-direction profile corresponding to a first direction along a direction and a plurality of second-direction profiles corresponding to a second direction opposite to the first direction. A profile selection unit that selects the second-direction profile to be used from the plurality of second-direction profiles based on the specific information, and a plurality of the firsts corresponding to the plurality of pixels. An image acquisition unit that acquires target image data including one type of color value, a first partial print data for the partial print performed in the first direction using the target image data, and the second A print data generation unit that executes a generation process for generating a plurality of partial print data including the second partial print data for the partial print performed in the direction, and the generation process is the target image. Using the print data generation unit and the plurality of partial print data including a color conversion process for converting each of the plurality of first-class color values included in the data into the second-class color values. A print control unit that causes the print execution unit to print a print image based on the target image data by causing the print execution unit to perform the partial printing a plurality of times, and for the plurality of second directions. Each of the profiles is printed by the first partial printing based on the second type color value obtained by converting a specific first type color value using the first direction profile. Obtained by converting an image and the specific first-class color value using the second-direction profile. It is adjusted so as to reduce the color difference between the image printed by the second partial printing and the image printed by the second partial printing based on the color value of the second kind, and the plurality of profiles for the second direction are adjusted. The degree of the expected color difference is different from each other, and the print data generation unit executes the first generation process including the first color conversion process executed by using the first direction profile. Then, the second generation process including the second color conversion process executed by generating the first partial print data and using the profile for the second direction selected by the profile selection unit is performed. An image processing apparatus that executes and generates the second partial print data.

The degree of color difference that can occur between an image printed by partial printing performed in the first direction and an image printed by partial printing performed in the second direction is, for example, the printing conditions and observation of the printed image. It may vary depending on the conditions. According to the above configuration, when the first partial print data for partial printing performed in the first direction is generated, the color conversion process is executed using the profile for the first direction. Then, when generating the second partial print data for the partial print performed in the second direction, the profiles for the plurality of second directions having different expected color differences from each other based on the specific information. The color conversion process is performed using the profile for the second direction selected from the inside. As a result, when generating the second partial print data, an appropriate second direction profile according to the degree of color difference described above can be referred to. Therefore, it is possible to suppress color unevenness of an image printed by bidirectional printing.

The techniques disclosed in the present specification can be realized in various forms, for example, a printing device, a control method of a print execution unit, a printing method, and a computer program for realizing the functions of these devices and methods. , A recording medium on which the computer program is recorded, and the like can be realized.

It is a block diagram which shows the structure of the printing system 1000 of an Example. It is a figure which shows the schematic structure of the printing mechanism 100. It is explanatory drawing of the operation of the printing mechanism 100. It is a figure which conceptually shows the color gamut that can be expressed by the outbound printing and the inbound printing. It is a flowchart of making a plurality of profiles of 1st Example. It is a figure which shows an example of a UI screen. It is a flowchart of image processing. It is a flowchart of a high-speed printing process. It is explanatory drawing of the observation angle θ. It is a flowchart of creation of a plurality of profiles of 2nd Example. It is a figure which shows an example of the detailed setting screen of the 2nd Example. It is a figure which shows an example of the detailed setting screen of a modification.

A. First Example:
A-1: Configuration of Printing System 1000 Next, an embodiment will be described based on an embodiment. FIG. 1 is a block diagram showing a configuration of the printing system 1000 of the embodiment.

The printing system 1000 includes a printer 200 and a terminal device 300 as an image processing device of this embodiment. The printer 200 and the terminal device 300 are communicably connected to each other via a wired or wireless network NW.

The terminal device 300 is a computer used by the user of the printer 200, and is, for example, a personal computer or a smartphone. The terminal device 300 includes a CPU 310 as a controller of the terminal device 300, a non-volatile storage device 320 such as a hard disk drive, a volatile storage device 330 such as a RAM, an operation unit 360 such as a mouse and a keyboard, and a liquid crystal display. It includes a display unit 370 and a communication unit 380. The communication unit 380 includes a wired or wireless interface for connecting to the network NW.

The volatile storage device 330 provides a buffer area 331 that temporarily stores various intermediate data generated when the CPU 310 performs processing. The non-volatile storage device 320 stores the computer program PG1 and a plurality of profile FPs, RP1 to RP4. The computer program PG1 and the plurality of profile FPs, RP1 to RP4, are provided by the manufacturer of the printer 200, for example, in a form downloaded from a server or stored in a DVD-ROM or the like. The CPU 310 functions as a printer driver that controls the printer 200 by executing the computer program PG1. The CPU 310 as a printer driver, for example, executes image processing described later to cause the printer 200 to print an image.

Each of the plurality of profiles FP, RP1 to RP4 is a profile that defines the correspondence between the color value (RGB value) of the RGB color system and the color value (CMYK value) of the CMYK color system. The plurality of profile FPs, RP1 to RP4, are used for color conversion processing for converting RGB values into CMYK values in image processing described later. The RGB value is a color value including three component values of red (R), green (G), and blue (B). The CMYK values include a plurality of component values corresponding to a plurality of types of inks used for printing, and in this embodiment, component values of cyan (C), magenta (M), yellow (Y), and black (K). It is a color value. The RGB value and the CMYK value are, for example, 256 gradation values. The plurality of profiles FP, RP1 to RP4 are, for example, look-up tables. The plurality of profile FPs, RP1 to RP4, will be described later.

The printer 200 includes, for example, a printing mechanism 100, a CPU 210 as a controller of the printer 200, a non-volatile storage device 220 such as a hard disk drive, a volatile storage device 230 such as a RAM, and a button for acquiring an operation by a user. It is provided with an operation unit 260 such as a touch panel, a display unit 270 such as a liquid crystal display, and a communication unit 280. The communication unit 280 includes a wired or wireless interface for connecting to the network NW. The printer 200 is communicably connected to an external device, for example, a terminal device 300, via the communication unit 280.

The volatile storage device 230 provides a buffer area 231 that temporarily stores various intermediate data generated when the CPU 210 performs processing. The computer program PG2 is stored in the non-volatile storage device 220. In this embodiment, the computer program PG2 is a control program for controlling the printer 200, and may be stored and provided in the non-volatile storage device 220 at the time of shipment of the printer 200. Instead of this, the computer program PG2 may be provided in a form downloaded from a server, or may be provided in a form stored in a DVD-ROM or the like. By executing the computer program PG2, the CPU 210 controls the printing mechanism 100 according to, for example, partial print data and direction information (described later) transmitted from the terminal device 300 by image processing described later, and print media (for example, paper). Print the image on top.

The printing mechanism 100 ejects inks (droplets) of C, M, Y, and K to perform printing. The printing mechanism 100 includes a printing head 110, a head driving unit 120, a main scanning unit 130, and a conveying unit 140.

FIG. 2 is a diagram showing a schematic configuration of the printing mechanism 100. As shown in FIG. 2A, the main scanning unit 130 slides to reciprocally hold the carriage 133 on which the print head 110 is mounted and the carriage 133 in the main scanning direction (X direction in FIG. 2). It includes a shaft 134 and. The main scanning unit 130 reciprocates the carriage 133 along the sliding shaft 134 by using the power of a main scanning motor (not shown). As a result, the main scanning in which the print head 110 is reciprocated along the main scanning direction (X direction) with respect to the paper M is realized.

While holding the paper M, the transport unit 140 transports the paper M in the transport direction (+ Y direction in FIG. 2) intersecting the main scanning direction. As shown in FIG. 2, a paper base 145, an upstream roller pair 142, and a downstream roller pair 141 are provided. Hereinafter, the upstream side (-Y side) in the transport direction is also simply referred to as an upstream side, and the downstream side (+ Y side) in the transport direction is also simply referred to as a downstream side.

The upstream roller pair 142 holds the paper M on the upstream side (−Y side) of the print head 110, and the downstream roller pair 141 holds the paper M on the downstream side (+ Y side) of the print head 110. The paper base 145 is arranged at a position between the upstream roller pair 142 and the downstream roller pair 141 and at a position facing the nozzle forming surface 111 of the print head 110. The paper M is conveyed by driving the downstream roller pair 141 and the upstream roller pair 142 by a transfer motor (not shown).

The head drive unit 120 (FIG. 1) supplies a drive signal to the print head 110 to drive the print head 110 while the main scanning unit 130 is performing the main scan of the print head 110. The print head 110 ejects ink onto the paper conveyed by the conveying unit 140 to form dots according to the drive signal.

FIG. 2B shows the configuration of the print head 110 as viewed from the −Z side (lower side in FIG. 2). As shown in FIG. 2 (B), on the nozzle forming surface 111 of the print head 110, a plurality of nozzle rows composed of a plurality of nozzles, that is, nozzle rows for ejecting the above-mentioned C, M, Y, and K inks. NC, NM, NY, and NK are formed. Each nozzle row contains a plurality of nozzles NZ. The positions of the plurality of nozzles NZ in the transport direction (+ Y direction) are different from each other, and the plurality of nozzles NZ are arranged at a predetermined nozzle interval NT along the transport direction. The nozzle spacing NT is the length in the transport direction between two nozzles NZ adjacent to each other in the transport direction among the plurality of nozzles NZ. Among the nozzles constituting these nozzle rows, the nozzle NZ located on the most upstream side (-Y side) is also referred to as the most upstream nozzle NZu. Further, among these nozzles, the nozzle NZ located on the most downstream side (+ Y side) is referred to as the most downstream nozzle NZd. The length obtained by adding the nozzle interval NT to the length in the transport direction from the most upstream nozzle NZu to the most downstream nozzle NZd is also referred to as a nozzle length D.

The positions of the nozzle rows NC, NM, NY, and NK in the main scanning direction are different from each other, and the positions in the sub scanning direction overlap each other. For example, in the example of FIG. 3, the nozzle row NM is arranged in the + X direction of the nozzle row NY that ejects Y ink.

A-2. Outline of Printing The printing mechanism 100 alternately performs partial printing in which dots are formed on the paper M by the print head 110 while performing main scanning by the main scanning unit 130, and sub-scanning (conveying the paper M) by the transport unit 140. By executing this a plurality of times, the print image OI is printed on the paper M.

FIG. 3 is an explanatory diagram of the operation of the printing mechanism 100. 3 (A) and 3 (B) show the printed image OI printed on the paper M. The printed image OI includes a plurality of partial image PIs. In the example of FIG. 3, the printed image OI includes partial images PI1 to PI5. Each partial image PI is an image printed by one partial printing. The printing direction of partial printing is either the outward direction or the return direction. That is, in the partial printing, the outbound printing that forms dots while performing the main scan in the outward direction (+ X direction in FIG. 3) and the return route that forms dots while performing the main scan in the inbound direction (−X direction in FIG. 3). Either printing or. In FIG. 3, a solid arrow in the + X direction or the −X direction is attached in the partial image. The partial image (for example, PI1, PI3, PI5 in FIG. 3A) with a solid arrow in the + X direction is an outward partial image printed by outbound printing. The partial image (for example, PI2 and PI4 in FIG. 3A) with a solid arrow in the −X direction is a return partial image printed by the return print.

In FIG. 3, the arrow in the −Y direction from one partial image PI (for example, partial image PI1) toward another partial image PI (for example, partial image PI2) adjacent in the −Y direction indicates the transport of the paper M. It corresponds to (secondary scanning). That is, the arrow in the −Y direction in FIG. 3 indicates that the print head 110 moves in the −Y direction with respect to the paper M shown in FIG. 3 when the paper M is conveyed in the conveying direction (+ Y direction). Is shown. As shown in FIG. 3, the printing of this embodiment is so-called one-pass printing, and the length of each partial image in the transport direction and the transport amount of the paper M at one time are the nozzle length D.

As an example of printing, bidirectional printing is shown in FIG. 3 (A), and unidirectional printing is shown in FIG. 3 (B). Bidirectional printing is printing performed by combining outbound printing and inbound printing. As shown in FIG. 3A, in bidirectional printing, for example, outbound printing and inbound printing are alternately executed. As shown in FIG. 3B, the one-way printing is printing performed only by the outbound printing. Alternatively, the one-way printing may be printing performed only by the return printing.

When unidirectional printing is performed, the main scan is performed between two consecutive partial prints without forming dots. The dashed arrow in FIG. 3B indicates the main scan performed without forming dots. In bidirectional printing, the printing speed of bidirectional printing is faster than that of unidirectional printing because the main scan is not performed without forming dots.

Here, as shown in FIG. 2B, as shown in the print head 110, the positions of the CMYK nozzle rows NC, NM, NY, and NK are different from each other in the main scanning direction. Therefore, when the CMYK dots are formed at the same position on the paper M, the dot formation order is different between the outbound printing and the inbound printing. For example, in the example of FIG. 2B, dots are formed in the order of K, C, M, Y in the outbound printing, and conversely, dots are formed in the order of Y, M, C, K in the inbound printing. Will be done. As a result, in the region where dots of a plurality of colors overlap, the order in which the dots overlap differs between the outward path partial image and the return path partial image. Therefore, even if the outbound partial image and the inbound partial image are printed using the same dot data, the printed colors may be different from each other. In this way, there is a color difference (also referred to as a color difference between round trips) printed between the outward partial image and the return partial image.

Due to such a color difference between round trips, for example, the color gamut that can be expressed by outbound printing and the color gamut that can be expressed by inbound printing are different. FIG. 4 is a diagram conceptually showing a color gamut that can be expressed by outbound printing and inbound printing. In FIG. 4, the color gamut is shown in the CIELAB color space, which is a color space that does not depend on the device such as the print execution unit. The outward color gamut OG shown by the solid line is a color gamut that can be expressed by the outward printing, and the return color gamut RG shown by the broken line is a color gamut that can be expressed by the return printing. In order to suppress color unevenness caused by such a color difference between round trips, in this embodiment, the plurality of profiles include one outbound profile FP and a plurality of inbound profiles RP1 to RP4. ..

The outbound profile FP is used when generating partial print data for outbound printing. When the outbound profile FP is used, the color gamut expressed in the outbound printing is substantially equal to the outbound color gamut OG that can be expressed in the outbound printing.

The plurality of return profile profiles RP1 to RP4 are used when generating partial print data for return print. These return profile RP1 to RP4 are adjusted (color matching) with respect to the outward profile FP so as to reduce the color difference between the round trips described above. Specifically, these return profile RP1 to RP4 have the color of the outward partial image printed based on the CMYK value obtained by converting a specific RGB value using the outward profile FP, and the specific RGB. The values are adjusted so as to be close to the color of the return route partial image printed based on the CMYK values obtained by converting the values using the return route profiles RP1 to RP4.

Here, the reason why a plurality of return profile profiles RP1 to RP4 are prepared will be described. The degree of color difference between reciprocations described above varies depending on the type of paper used for printing. The cause is not always clear, but for example, since the amount of ink Ik permeated and the speed of permeation of ink Ik on paper differ depending on the type of paper, the degree of color difference due to the difference in how the ink Ik overlaps described above is Presumed to be different. In particular, plain paper, which is often used for bidirectional printing, has various types depending on the country, region, manufacturer, etc., and the characteristics (for example, thickness, texture, material) differ greatly. For this reason, the degree of color difference between round trips differs depending on the type of plain paper. For example, experiments have confirmed that the maximum value of the color difference between round trips, which is indicated by the distance in the CIELAB color space, varies in the range of about 4 to 10 depending on the type of plain paper.

The degree of color difference assumed as the reciprocating color difference differs between the plurality of profiles RP1 to RP4. Therefore, the adjustment amount for reducing the color difference between reciprocations is different between the plurality of profiles RP1 to RP4. For example, among a plurality of profiles RP1 to RP4, the larger the number (1 to 4) at the end of the code, the greater the degree of expected color difference, and the larger the amount of adjustment for reducing the reciprocating color difference. ..

A-3. Creating a Profile FIG. 5 is a flowchart for creating a plurality of profiles FP, RP1 to RP4 of the first embodiment. The profile is created, for example, by the manufacturer of the printer 200 during the development of the printer 200.

In S10, the creator creates the outbound profile FP. The outbound profile FP is created, for example, as follows. The creator sets a target color value TC to be expressed for each of a plurality of representative values GV (grid values) of RGB values. The plurality of representative values GV are 9 specific values (0, 32, 64, 96, 128) in which each value of R, G, and B is set substantially evenly between 0 and 255 in the RGB color space. , 160, 192, 224, 255), and 729 (9 to the third power) RGB values obtained by setting.

The target color value TC is represented by, for example, a color value (also referred to as a Lab value) in the CIELAB color space, which is a device-independent color space. Further, the creator prints a plurality of patches based on the plurality of CMYK values by outbound printing using the printer 200. The creator measures each of the plurality of patches with a colorimeter to obtain a Lab value indicating the color of each patch. The creator determines the correspondence between the CMYK value and the Lab value based on the Lab value of each patch. The creator determines a CMYK value corresponding to a target color value TC (Lab value) of a representative value GV of RGB values based on the correspondence relationship. The creator creates a lookup table showing the correspondence between the plurality of representative value GVs of RGB values and the CMYK values corresponding to each of the plurality of representative value GVs as the outbound profile FP.

In S20, the outbound profile FP is used to generate test image print data for printing the test image. The test image includes, for example, a plurality of patches corresponding to the plurality of representative values GV of the RGB values described above. Each patch is a solid image with the color indicated by the corresponding representative value GV. The creator prepares, for example, RGB image data showing a test image. The RGB image data is image data that includes a plurality of RGB values corresponding to a plurality of pixels and indicates the color of each pixel by the RGB values. The creator uses a computer such as a personal computer to execute a color conversion process using the outbound profile FP on the RGB image data to convert the RGB image data into CMYK image data. The CMYK image data is image data indicating the color of each pixel with the above-mentioned CMYK value. The creator uses a computer to execute halftone processing on the CMYK image data to generate test image print data. For the halftone processing, for example, a known error diffusion method or dither method is used. The test image print data is so-called dot data that represents the dot formation state for each pixel and each ink color. The dot formation state is, for example, one of four states of "large dot", "medium dot", "small dot", and "no dot". Instead of this, the dot formation state may be one of two states, "with dots" and "without dots".

In S30, the creator selects one paper from the four types of plain paper used for creating the profile. As described above, the four types of plain paper have different maximum values of the color difference between round trips indicated by the distance in the CIELAB color space. That is, the four types of plain paper have different degrees of color difference between reciprocations that are expected when used for printing.

In S40, the creator uses the test image print data generated in S20 to cause the printer 200 to print the test image by one-way printing in the outward direction.

In S50, the creator uses the test image print data generated in S20 to cause the printer 200 to print the test image by one-way printing in the return direction.

In S60, the color difference between the test image printed in the outward direction in S40 and the test image printed in the inbound direction in S50 is measured, and the color difference between round trips is measured for each patch (that is, the representative value GV of the RGB value). Specify (for each). The color difference between the round trips is indicated by, for example, the Euclidean distance in the CIELAB color space. For example, the creator measures the color of each patch of both test images using a spectrophotometer to obtain a color value (Lab value) of the CIELAB color space indicating the color of each patch. The creator calculates the color difference between the test images for each patch as the round-trip color difference using the Lab value indicating the patch color of both test images.

In S70, the creator creates a return profile corresponding to the paper selected in S30 based on the round-trip color difference for each specified patch. For example, the creator sets a target color value TCr to be expressed for each of a plurality of representative values GV (grid values) of RGB values. Here, each target color value TCr for the return route profile is set to a value obtained by modifying each target color value TC used when creating the outward route profile FP in S10 based on the round-trip color difference of the corresponding patch. Will be done. For example, it is shown that the color difference between the round trips of the patch corresponding to a specific representative value GV is reduced by ΔL when printed by the return print, as compared with the case where the patch is printed by the outward print. To do. In this case, for example, the target color value TCr of the specific representative value GV is set to a color value whose brightness is higher by ΔL than the target color value TC of the specific representative value GV for the outbound profile FP. ..

The creator selects a CMYK value representing the target color value TCr of each representative value GV as a CMYK value associated with the representative value GV. As a result, a lookup table showing the correspondence relationship between the plurality of representative value GVs of RGB values and the CMYK values corresponding to each of the plurality of representative value GVs is created as a return profile. The selection of the CMYK value representing the target color value TCr is performed based on the correspondence between the CMYK value and the Lab value determined for creating the outbound profile FP in S10. As a result, the return profile corresponding to the paper selected in S30 is created.

In S80, the creator determines whether or not a return profile has been created for all papers, that is, the four types of plain papers prepared. If the return profile corresponding to some plain papers has not been created (S80: NO), the creator returns to S30 and selects the next plain paper. When all the return trip profiles corresponding to the four types of plain paper are created (S80: YES), the creator ends the profile creation. The return profiles corresponding to the four types of plain paper are the return profiles RP1 to PR4 in FIG.

As can be seen from the above description, in the first return profile RP1 of this embodiment, the color of the image printed by the return print on the first type plain paper using the test image print data is the test image print data. It is a profile adjusted so as to approach the color of an image printed by outbound printing on a first-class plain paper. Then, in the second return route profile RP2, the color of the image printed by the return route printing on the second type plain paper using the test image print data is transferred to the second type plain paper using the test image print data. It is a profile adjusted so as to approach the color of the image printed by printing. As a result, by properly using these return profile RP1 to PR4 in the image processing described later, it is possible to reduce different color unevenness depending on the type of plain paper in the printed image OI printed by bidirectional printing.

A-4. UI screen Next, in the image processing described later, a user interface (UI) screen displayed on the display unit 370 when the CPU 310 of the terminal device 300 receives a user's instruction will be described. FIG. 6 is a diagram showing an example of a UI screen.

The main screen WD1 of FIG. 6A is a UI screen for making general settings related to printing. The detailed setting screen WD2 of FIG. 6B is a UI screen for making detailed settings related to plain paper.

The main screen WD1 is displayed when the printer driver (computer program PG1) is started, for example, via an application program such as document creation software or image creation software. The main screen WD1 has a preview area PV on which a printed image is displayed, a plurality of input elements (UI parts) for the user to input various settings related to printing, for example, pull-down menus PM1 to PM3, and an input field F1. And, including.

The input field F1 is used by the user to input the number of copies to be printed. The pull-down menu PM1 includes a plurality of options indicating a plurality of pre-registered paper sizes. For example, the plurality of options indicate A4, A3, A5, postcards, and the like. The pull-down menu PM2 includes an option indicating color printing and an option indicating monochrome printing. The pull-down menu PM3 includes a plurality of options indicating a plurality of pre-registered paper types. For example, the plurality of options indicate plain paper, glossy paper, wood-free paper, and the like.

The user can operate the pull-down menus PM1 to PM3 to input a selection instruction for selecting one of the plurality of options. For example, the user can operate the pull-down menu PM3 to input a selection instruction for selecting the type of paper to be used for printing.

The main screen WD1 further includes a button BT1 for detailed setting, a button BT2 for instructing to end the display of the main screen WD1 without printing, and a button BT3 for instructing the execution of printing. Includes. For example, the user operates the pull-down menus PM1 to PM3 described above to select a desired option, inputs the number of copies to be printed in the input field F1, and then presses the button BT3. This allows the user to instruct printing with the desired settings.

When the button BT1 is pressed, a UI screen (not shown) for selecting various detailed setting items related to printing is displayed on the display unit 370. In this embodiment, when the option indicating "plain paper" is selected by the pull-down menu PM3, when the button BT1 is pressed, the detailed setting screen WD2 of FIG. 6B is displayed on the display unit 370. To.

The detailed setting screen WD2 of FIG. 6B includes a slide bar SB as an input element for selecting a color matching level (also referred to as intensity) when plain paper is used. The slide bar SB includes a bar BR and a slider SD that moves along the bar BR in response to a user operation. The slider SD can be moved to any of the four specific positions P1 to P4 along the bar BR. The user can specify one level from the four levels 1 to 4 by moving the slider SD to a position indicating a desired color matching level among the specific positions P1 to P4. .. In other words, the specific positions P1 to P4 are positions corresponding to the four options indicating the four levels 1 to 4, and the user can use one of the four options via the slider SD. You can enter selection instructions to select the options of.

The detailed setting screen WD2 further includes a button BT4 for instructing to cancel the display of the detailed setting screen WD2 and returning to the main screen WD1, and an apply button BT5. When the button BT1 is pressed, the specification of the color matching level corresponding to the position of the slider SD at that time becomes effective.

A-5. Image processing FIG. 7 is a flowchart of image processing. The CPU 310 (FIG. 1) of the terminal device 300 starts the image processing of FIG. 6 when the printer driver (computer program PG1) is started, for example, via an application program such as document creation software or image creation software. ..

In S100, the CPU 310 displays the UI screen including the main screen WD1 and the detailed setting screen WD2 described above on the display unit 370, and receives user instructions regarding various printing-related settings.

In step S105, the CPU 310 determines whether or not a print instruction has been input. Specifically, when the button BT3 of the main screen WD1 of FIG. 6A is pressed, it is determined that the print instruction has been input. When the print instruction is not input (S105: NO), the CPU 310 maintains the display of the UI screen and continues accepting the above-mentioned settings (S100).

When a print instruction is input (S105: YES), in S110, the CPU 310 acquires the print-related settings input via the UI screen. The settings acquired here include the selection instructions regarding the type of paper to be used for printing and the selection instructions of the color matching level described above.

In S115, the CPU 310 acquires the target image data to be used for printing. The target image data is acquired from, for example, an application program that starts the printer driver (computer program PG1). The target image data to be acquired is RGB image data. When the acquired target image data is not RGB image data, for example, conversion processing such as rasterization processing is executed on the target image data to convert it into RGB image data.

In S120, the CPU 310 determines whether or not the type of paper to be used for printing is plain paper, based on the settings acquired in S110. When the type of paper to be used for printing is plain paper (S120: YES), in S125, the CPU 310 is selected from four types of return profiles RP1 to RP4 according to the selected color matching level. Select one return profile to use. The selected color matching level is indicated by the selection instruction included in the setting acquired in S110. In this embodiment, the color matching levels 1, 2, 3, and 4 correspond to the return trip profiles FP1, RP2, RP3, and PR4, respectively, and the return trip profile corresponding to the selected level is selected. For example, when the selection instruction for selecting level 1 is acquired, the first return profile RP1 is selected, and when the selection instruction for selecting level 2 is acquired, the second return profile RP2 is selected. ..

In S130, the CPU 310 executes high-speed printing processing and ends the image processing. The high-speed printing process is a process of generating print data using the target image data and causing the printer 200 to print the image by bidirectional printing (FIG. 3A) using the print data. The outbound profile FP and one inbound profile selected in S125 are used to generate print data in the high-speed printing process. The high-speed printing process will be described later.

When the type of paper to be used for printing is plain paper (S120: YES), in S135, the CPU 310 executes high-quality printing processing and ends the image processing. The high-quality printing process is a process of generating print data using the target image data and causing the printer 200 to print the image using the print data. In the high-quality printing process, the printing speed is slower than that of the bidirectional printing executed in the high-speed printing process, but the image quality of the printed image is high. For example, in the high-quality printing process, the one-way printing of FIG. 3B is executed. When the one-way printing of FIG. 3B is performed, only the outbound profile FP is used when generating the print data. In the high-quality printing process, a printing method different from the one-way printing of FIG. 3B, for example, so-called multi-pass printing in which one partial image is printed by partial printing two or more times is adopted. You may.

As described above, in this embodiment, the printing to be performed is changed according to the type of paper to be used for printing. In general, plain paper is cheaper than glossy paper and high-quality paper, and color bleeding is more likely to occur than glossy paper and high-quality paper. For this reason, when plain paper is used, it is considered that the printing speed is more important than the image quality of the printed image. On the other hand, when paper different from plain paper, for example, glossy paper or high-quality paper, is used, higher image quality is required as compared with the case where plain paper is used, and it is considered that printing speed is not important. .. Therefore, in this embodiment, when plain paper is used, a high-speed printing process is executed, and when a paper different from plain paper is used, a high-quality printing process is executed. As a result, appropriate printing can be performed according to the type of paper.

A-6. High-speed printing process The high-speed printing process of S130 in FIG. 7 will be described. FIG. 8 is a flowchart of the high-speed printing process. In S305, the CPU 310 acquires the partial image data for one partial print out of the target image data as the attention partial image data. The partial image PI corresponding to the attention partial image data is also referred to as a attention partial image. Further, partial printing for printing a attention partial image is also referred to as attention partial printing.

In S310, the CPU 310 determines whether or not the partial image of interest is the partial image printed in the first partial print. For example, the partial image PI1 of FIG. 3A is a partial image printed in the first partial print. When the attention partial image is the partial image PI1 to be printed in the first partial print (S310: YES), in S330, the CPU 310 sets the print direction (also referred to as the attention print direction) of the attention partial print in the outward direction. decide.

When the attention partial image is not the partial image PI1 printed in the first partial print (S310: NO), in S320, S330, and S345, the CPU 310 sets the attention print direction to the print direction of the immediately preceding partial print (immediately before). Determined in the opposite direction (also called the printing direction). Specifically, in S320, the CPU 310 determines whether or not the immediately preceding print direction is the outbound direction. When the immediately preceding print direction is the outward direction (S320: YES), in S345, the CPU 310 determines the print direction of interest in the return direction. When the immediately preceding print direction is the return direction (S320: NO), in S330, the CPU 310 determines the print direction of interest in the outward direction.

When the print direction of interest is determined in the outbound direction, in S335 and S340, the CPU 310 executes an outbound generation process for generating outbound partial print data for outbound printing. Specifically, in S335, the CPU 310 executes a color conversion process on the attention portion image data using the outbound profile FP. As a result, the partial image data of interest is converted from the RGB image data to the CMYK image data. In S340, the CPU 310 executes halftone processing on the color-converted attention portion image data to generate outbound partial print data as partial print data for attention portion printing. The halftone process is performed using a known method, for example, an error collection method. The generated partial print data is data (also referred to as dot data) indicating a dot formation state for each color component and each pixel. The dot formation state is, for example, one of "with dots" and "without dots". Instead of this, the dot formation state may be any one of "large dot", "medium dot", "small dot", and "no dot".

When the print direction of interest is determined in the return direction, in S350 and S355, the CPU 310 executes a return generation process for generating return partial print data for return printing. Specifically, in S350, the CPU 310 executes color conversion processing on the partial image data of interest using one return profile selected in S125 among the plurality of return profiles RP1 to RP4. To do. In S355, the CPU 310 executes halftone processing on the color-converted attention portion image data to generate return route partial print data as partial print data for attention portion printing.

In S360, the CPU 310 transmits the generated partial print data and the direction information indicating the print direction of the partial print of interest to the printer 200. When the printer 200 receives the partial print data and the direction information, the CPU 210 of the printer 200 executes the partial print according to the partial print data and the direction information. For example, the CPU 210 executes outbound printing when the direction information indicates the outward direction and prints the attention portion image, and executes return printing when the direction information indicates the return direction to the attention portion. Print the image.

In S365, the CPU 310 determines whether or not all the partial image data of the printed image OI has been processed. If there is unprocessed partial image data (S365: NO), the CPU 310 returns the processing to S305. When all the partial image data has been processed (S365: YES), the CPU 310 ends the high-speed printing process.

In the present embodiment described above, the non-volatile storage device 320 that stores a plurality of profile FPs, RP1 to RP4, is an example of a storage unit. In S125 of FIG. 7, the CPU 310 that selects the return profile to be used from the plurality of return profiles RP1 to RP4 based on the user's selection instruction is an example of the profile selection unit. In S115 of FIG. 7, the CPU 310 that acquires the target image data (RGB image data) is an example of the image acquisition unit. In S330 to S355 of FIG. 8, the CPU 310 that executes the generation process of generating a plurality of partial print data including the outward route partial print data and the return route partial print data using the target image data prints. This is an example of the data generation unit. In S360 of FIG. 8, the CPU 310 that causes the printer 200 to execute a plurality of times of partial printing as a print execution unit by using a plurality of partial print data is an example of a print control unit. Each of the plurality of return profile profiles RP1 to RP4 is adjusted so as to reduce the color difference between round trips, and the expected degree of color difference between round trips differs from each other. The outbound generation process (S335, S340 in FIG. 8) for generating the outbound partial print data includes a color conversion process (S335 in FIG. 8) executed using the outbound profile FP. The return route generation process (S350, S355 in FIG. 8) for generating the return route partial print data is a color conversion process (S350 in FIG. 8) executed using one return path profile selected in S125 of FIG. 7. )including. As described above, the degree of color difference between reciprocations may vary depending on the printing conditions, for example, the type of paper used. According to this embodiment, when the outward route partial print data is generated, the color conversion process is executed using the outward route profile FP, and when the return route partial print data is generated, the expected round-trip color difference is achieved. The color conversion process is performed using a profile selected from a plurality of return profiles RP1 to RP4 that are different from each other. As a result, when generating the partial print data for the return route, an appropriate return route profile according to the degree of the color difference between the round trips can be referred to. Therefore, in the printed image OI printed by bidirectional printing, color unevenness due to the color difference between reciprocations can be suppressed.

Further, since there is only one outbound profile FP, for example, the memory capacity required for storing the profile (capacity of the non-volatile storage device 320 in this embodiment) is reduced as compared with the case where a plurality of outbound profiles are used. be able to.

Further, in the above embodiment, in S100 to S110, the user gives an instruction to select one option from the four options indicating levels 1 to 4 via the detailed setting screen WD2 (FIG. 6B). The CPU 310 acquired from is an example of an instruction acquisition unit. For example, the CPU 310 selects the first return profile RP1 when the selection instruction for selecting level 1 is acquired, and selects the second return profile RP2 when the selection instruction for selecting level 2 is acquired. Select (S125 in FIG. 7). As a result, the return profile to be used is selected based on the option selection instruction obtained from the user. Therefore, it is possible to provide the user with a means for suppressing color unevenness of the printed image OI by inputting a selection instruction.

In the above embodiment, the position indicating the level 1 to 4 on the slide bar SB of the detailed setting screen WD2 is an option indicating the level 1 to 4 in which the color of the image printed by the return printing is adjusted. For example, the option indicating level 1 is an option indicating that the level at which the color of the image printed by the return printing is adjusted is the first level, and the option indicating level 2 is an option indicating the image printed by the return printing. It can be said that it is an option indicating that the level at which the color of is adjusted is the second level higher than the first level. As a result, for example, when the color unevenness is conspicuous in the image printed by selecting level 1, the user can suppress the color unevenness of the image by selecting level 2 and printing the image. As a result, it is possible to provide the user with a more effective means for suppressing color unevenness of the printed image OI.

As can be seen from the above description, the outward route direction of this embodiment is an example of the first direction, and the return route direction is an example of the second direction. The outward profile FP is an example of a profile for the first direction, and the return profiles RP1 to RP4 are examples of a plurality of profiles for the second direction. The outbound generation process is an example of the first generation process, and the inbound generation process is an example of the second generation process.

B. Second Example In the first embodiment, focusing on the fact that the degree of color difference between reciprocations differs depending on the type of plain paper, a plurality of types of return profile RP1 to RP4 corresponding to a plurality of types of plain paper are created (FIG. 5). ), Stored in the non-volatile storage device 320. Instead of this, in the second embodiment, a plurality of observation angles are focused on that the degree of color difference between reciprocations differs depending on the angle at which the printed image OI is observed (also referred to as the observation angle θ). Multiple types of return profiles corresponding to θ are created.

B-1. Observation angle and color difference between reciprocations FIG. 9 is an explanatory diagram of the observation angle θ. As shown in FIG. 9A, in this embodiment, the paper M is irradiated with white light from the light source 20 in a predetermined irradiation direction LA. The irradiation direction LA is a direction forming an angle of 45 degrees with respect to the normal VL on the surface of the paper M.

The reference observation direction OA0 is a direction perpendicular to the irradiation direction LA on a plane (also referred to as an observation plane) including the normal VL and the light source 20. The reference direction OA (0) is set to the position of 0 degrees, and the observation angle θ is defined by the angle with respect to the reference direction OA0. For example, the angle of the direction OA (45) in FIG. 9A with respect to the reference observation direction OA0 is 45 degrees. Therefore, the direction OA (45) is the direction in which the observation angle θ is 45 degrees. Direction OA (45) is the direction along the normal VL. The reference direction OA (0) is a direction in which the observation angle θ is 0 degrees. It can be said that the observation angle θ is the angle of the line of sight with respect to the printed paper M assumed at the time of observation.

FIG. 9A schematically shows a cyan dot CD formed of cyan ink and a magenta dot MD formed of magenta ink. In FIG. 9A, a part of the magenta dot MD is superposed on the part of the cyan dot CD. In the example of FIG. 9 (A), when viewed from the direction OA (0) where the observation angle θ is 0 degrees, the observed light path, that is, the line indicating the irradiation direction LA in FIG. 9 (A). The route indicated by the line indicating the direction OA (0) is a route that passes through the magenta dot MD and the cyan dot CD once. On the other hand, in the example of FIG. 9A, when viewed from the direction OA (45) where the observation angle θ is 45 degrees, the observed light path, that is, the irradiation direction in FIG. 9A. The route indicated by the line indicating LA and the line indicating the direction OA (45) is a route that passes through the magenta dot MD and the cyan dot CD and then passes through the magenta dot MD again. Due to such a difference in the light path, the color observed when viewed from the direction OA (0) where the observation angle θ is 0 degrees and the color observed when viewed from the direction OA (45) where the observation angle θ is 45 degrees. It is different from the color observed when it is used.

Here, in the outbound printing and the inbound printing, the order in which the cyan dot CD and the magenta dot MD overlap is reversed as described above. As a result, the above-mentioned reciprocating color difference occurs between the image printed by the outbound printing and the image printed by the inbound printing even when viewed at the same observation angle θ. The degree of color difference between reciprocations also differs depending on the observation angle θ.

In FIG. 9B, the directions OA (-15), OA (0), in which the observation angles θ are −15 degrees, 0 degrees, 15 degrees, 25 degrees, 45 degrees, 75 degrees, and 110 degrees, respectively. OA (15), OA (25), OA (45), OA (75), OA (110) are shown. According to the experiment, it has been confirmed that the color difference between reciprocations tends to increase as the observation angle θ increases depending on the color. In the second embodiment, in view of this, in order to reduce the color unevenness caused by the color difference between reciprocations that differs depending on the observation angle θ, -15 degrees, 0 degrees, 15 degrees, 25 degrees, 45 degrees, 75 degrees, Seven return profiles are created corresponding to seven observation angles θ of 110 degrees. The number of outbound profiles is one as in the first embodiment.

B-2. Creating a Profile FIG. 10 is a flowchart for creating a plurality of profiles according to the second embodiment. Similar to the first embodiment, the profile is created, for example, by the manufacturer of the printer 200 at the time of development of the printer 200.

The processing of S10, S20, S40, and S50 in FIG. 10 is the same as the processing of the same reference numerals in FIG. In S10, when creating the outbound profile, a plurality of patches are printed on, for example, standard plain paper, and the color measurement of each patch is the direction OA of 45 degrees, which is the standard observation angle θ. 45). At the end of S50, a test image printed by one-way printing in the outward direction and a test image printed by one-way printing in the return direction are prepared.

In S55B, the creator selects one observation angle θ from the above-mentioned seven types of observation angles θ. In S60B, the test image printed in the outward direction in S40 and the test image printed in the return direction in S50 are measured from the direction of the observation angle θ selected in S55B, and the color difference between reciprocations is measured. , Specified for each patch (that is, for each typical RGB value GV). In FIG. 9B, spectrophotometry arranged for color measurement from the directions of seven observation angles θ of -15 degrees, 0 degrees, 15 degrees, 25 degrees, 45 degrees, 75 degrees, and 110 degrees. Coloring devices 10a to 10g are shown. For example, when the selected observation angle θ is 25 degrees, the color measurement is performed using the spectrophotometer 10d. The creator measures the color of each patch of both test images from the direction of the selected observation angle θ using a spectrophotometer, and the color value (Lab value) of the CIELAB color space indicating the color of each patch. ) To get. The creator calculates the color difference between the test images for each patch as the round-trip color difference using the Lab value indicating the patch color of both test images.

In S70B, the creator creates a return profile corresponding to the observation angle θ selected in S55B based on the reciprocating color difference for each specified patch. The specific method for creating the return route profile is the same as the method for creating the return route profile in S70 of FIG. 5, for example.

In S80B, the creator determines whether or not the return profile corresponding to all seven observation angles θ has been created. If the return profile corresponding to some observation angles θ has not been created (S80B: NO), the creator returns to S55B and selects the next observation angle θ. When all the return paths corresponding to the seven observation angles θ have been created (S80B: YES), the creator ends the profile creation. The created seven types of return profiles and one outward profile are stored in the non-volatile storage device 320 of the printer 200.

As can be seen from the above description, one of the seven types of return profile of this embodiment is to use the test image print data to print an image printed on paper M by return print at a first angle (for example, observation). The color observed when observing at an angle θ = 45 degrees) is observed when observing the image printed on the paper M by outbound printing using the test image print data at the first angle. It is a profile adjusted to approach the color to be printed. Then, the other one of the seven types of return profiles corresponds to an image printed on paper M by return printing using the test image print data at a second angle (for example, an observation angle θ = 75 degrees). Adjust so that the color observed when observing at (angle) is close to the color observed when observing the image printed on paper M by outbound printing using the test image print data at the second angle. It is a profile that has been printed. As a result, in the image processing described later, by properly using these return profiles, it is possible to reduce color unevenness that differs depending on the observation angle θ in the image printed by bidirectional printing.

B-3. UI screen Next, in the image processing of the second embodiment, the UI screen displayed on the display unit 370 when the CPU 310 of the terminal device 300 receives the user's instruction will be described. FIG. 11 is a diagram showing an example of the detailed setting screen WD2b of the second embodiment.

In the second embodiment, the main screen WD1 of FIG. 6A is displayed on the display unit 370 as in the first embodiment. In the second embodiment, the detailed setting screen WD2b of FIG. 11 is displayed on the display unit 370 instead of the detailed setting screen WD2 of FIG. 6B of the first embodiment.

The detailed setting screen WD2b of FIG. 11 includes a slide bar SBb as an input element for selecting color matching when plain paper is used (that is, when bidirectional printing is performed in this embodiment). There is. The slide bar SBb includes a bar BRb and a slider SDb that moves along the bar BR in response to a user operation. The slider SDb can be moved to any of the seven positions along the bar BR that indicate the seven observation angles θ. By moving the slider SD to a position indicating the observation angle θ assumed when observing the printed image OI among the seven positions, the user can make one angle out of the seven observation angles θ. Can be specified. In other words, the 7 positions are 4 options indicating 7 kinds of observation angles θ, and the user selects 1 option from the 7 options via the slider SDb. You can enter selection instructions. The user selects one option (observation angle θ), for example, in consideration of the mode of use of the paper on which the printed image OI is printed. For example, when the paper is a poster, the observation angle θ is selected in consideration of the height at which the poster is posted and the positional relationship between the position where the poster is posted and the lighting.

B-4. Image processing The image processing of the second embodiment is the same as the image processing of FIG. 7 described in the first embodiment. However, in the second embodiment, the setting acquired in S110 of FIG. 7 includes a selection instruction of the observation angle θ input via the detailed setting screen WD2 instead of the selection instruction of the color matching level.

Further, in the second embodiment, in S125, the CPU 310 selects a return path profile corresponding to the selected observation angle θ indicated by the selection instruction from the above-mentioned seven types of return path profiles. For example, when the selection instruction to select 45 degrees as the observation angle θ is acquired, the return profile corresponding to 45 degrees is selected, and when the selection instruction to select 15 degrees is acquired, the selection instruction is set to 15 degrees. The corresponding return profile is selected. As a result, in the high-speed printing process of S130, the outbound route generation process including the color conversion process using one outbound profile (S335 in FIG. 8) and the color using the return profile selected according to the observation angle θ are used. The return route generation process including the conversion process (S350 in FIG. 8) is executed.

According to the second embodiment described above, the position indicating the seven types of observation angles θ on the slide bar SBb of the detailed setting screen WD2b is an option indicating the seven types of observation angles θ as described above. For example, the option indicating 45 degrees is an option indicating that the observation angle θ assumed at the time of observation is 45 degrees, and the option indicating 75 degrees is an option indicating that the observation angle θ assumed at the time of observation is 75 degrees. It is an option to show. As a result, the user can suppress the color unevenness of the image from being conspicuous during observation, for example, by selecting an option indicating the assumed observation angle θ. As a result, it is possible to provide the user with a more effective means for suppressing color unevenness of the image printed by bidirectional printing.

C. Modification example

(1) On the detailed setting screen WD2 (FIG. 6 (B)) of the first embodiment, the slide bar SB is used to select one option from the four options indicating the color matching levels 1 to 4. Instructions can be obtained from the user. The mode of acquiring the selection instruction from the user is not limited to this.

FIG. 12 is a diagram showing an example of the detailed setting screen WD2c of the modified example. The detailed setting screen WD2c of FIG. 12 includes a pull-down menu PMc instead of the slide bar SB as an input element (UI component) for inputting a selection instruction. The pull-down menu PMc includes a plurality of options indicating a plurality of types of plain paper registered in advance. In the example of FIG. 12, the plurality of options indicate the types of the plurality of types of plain paper by using the model number of the plain paper (such as "NP-001" in FIG. 12). The user can operate the pull-down menu PMc to input a selection instruction for selecting the model number of the plain paper to be used for printing.

Each model number included in the pull-down menu PMc is associated with one return path profile among the plurality of return path profiles RP1 to RP4 described above, which can reduce the color difference between the round trips of the plain paper of the model number. In S125 of FIG. 7, the CPU 310 selects one return profile associated with the selected model number indicated by the selection instruction as the return profile to be used. As a result, in the high-speed printing process of S130, the outbound route generation process including the color conversion process (S335 in FIG. 8) using one outbound route profile and the return route profile selected according to the model number of the plain paper were used. The return route generation process including the color conversion process (S350 in FIG. 8) is executed.

According to the modification described above, the plurality of options included in the pull-down menu PMc on the detailed setting screen WD2c are options indicating the model number of the plain paper as described above. For example, the option indicating the first model number (for example, "NP-001" in FIG. 12) is an option indicating that the plain paper used for printing is the first type plain paper having the first model number. , The option indicating the second model number (for example, “NP-002” in FIG. 12) is an option indicating that the plain paper used for printing is a second type plain paper having the second model number. As a result, the user can suppress color unevenness of the image printed by bidirectional printing by selecting an option indicating the type of plain paper used for printing. As a result, it is possible to provide the user with a more effective means for suppressing color unevenness of the image printed by bidirectional printing.

The plurality of options included in the pull-down menu PMc are not limited to the options indicating the type of plain paper using the model number. The multiple choices included in the pull-down menu PMc are the choices that indicate the type of plain paper using the texture of the paper (eg, "rough", "smooth", "normal"), and the plain paper using the thickness of the paper. It may be an option indicating the type of (for example, "thick", "thin", "normal"). Alternatively, the plurality of options included in the pull-down menu PMc may be options indicated by using the name of the plain paper, the country of origin or production area, the country of sale or the sales area, and the type of plain paper.

(2) In the second embodiment, seven types of return profiles are stored in the non-volatile storage device 320. For example, 4 corresponding to observation angles θ of -15 degrees, 15 degrees, 45 degrees, and 110 degrees. Only the return profile of the species may be stored in the non-volatile storage device 320.

In this case, for example, when an observation angle θ that does not have a corresponding return path profile is selected, the CPU 310 uses two CPU 310s as return path profiles to be used in S125 of FIG. 7 that are close to the selected observation angle θ. Two return profiles corresponding to the observation angle θ of are selected. The two observation angles θ close to the selected observation angle θ are, for example, the closest observation angle θ and the observation smaller than the selected observation angle θ among the observation angles θ larger than the selected observation angle θ. Of the angles θ, it is the closest observation angle θ. Then, in S350 of FIG. 8, the CPU 310 executes the color conversion process in the return path generation process using the two return path profiles. For example, when an observation angle θ of 0 degrees between -15 degrees and 15 degrees is selected, for example, in S125, the observation angle θ of -15 degrees and 15 degrees is set as the return profile to be used. The two corresponding return profiles are selected. Then, in the color conversion process of S340, the CPU 310 sets the specific RGB value to the first CMYK value obtained by using the return path profile corresponding to the observation angle θ of -15 degrees and the specific RGB value to 15 degrees. Color conversion is performed by setting the average CMYK value of the second CMYK value corresponding to the observation angle θ as the CMYK value corresponding to the specific RGB value.

Alternatively, on the detailed setting screen WD2b (FIG. 11), only four observation angles θ of -15 degrees, 15 degrees, 45 degrees, and 110 degrees in which the corresponding return profile exists may be selectable.

Similarly, in the first embodiment, instead of the four types of return profile RP1 to RP4, two or three types of return profiles may be stored in the non-volatile storage device 320.

(3) In each of the above embodiments, the return profile to be used is selected from the plurality of return profiles based on the selection instruction acquired from the user via the detailed setting screens WD2, WD2b, WD2c (). S125 in FIG. 7). Instead of this, the return profile to be used may be selected from a plurality of return profiles based on information different from the information input by the user. For example, the CPU 310 of the terminal device 300 causes the printer 200 to print a sample image on plain paper by one-way printing in the outward direction, and print the sample image on plain paper by one-way printing in the return direction. The user causes a scanner to read each of the plain paper on which these two types of sample images are printed to generate scan data. The terminal device 300 acquires these scan data and analyzes the scan data to determine the degree of color difference between round trips, for example, in four stages. The CPU 310 selects a return profile to be used from a plurality of return profiles according to the degree of color difference between round trips.

(4) In each of the above embodiments, one outbound profile and a plurality of inbound profiles are stored in the non-volatile storage device 320. Instead of this, a plurality of outbound profiles and one inbound profile may be stored in the non-volatile storage device 320. In this case, in S125 of FIG. 7, the CPU 310 selects one outbound profile to be used from the plurality of outbound profiles in response to the selection instruction. In the high-speed printing process of S130 of FIG. 7, the outbound route generation process including the color conversion process using the outbound route profile selected according to the selection instruction and the inbound route generation including the color conversion process using one inbound route profile are generated. Processing and is executed.

(5) The configuration of the UI screens (FIGS. 6, 11, and 12) of each of the above embodiments is an example, and is not limited thereto. For example, the detailed setting screens WD2 and WD2b of FIGS. 6 (B) and 11 use other input elements such as a pull-down menu, a radio button, and a field in place of the slide bars SB and SBb to set the level of color matching. The screen may be a screen that receives an input of an option selection instruction indicating the observation angle θ. Further, the detailed setting screen WD2c of FIG. 12 may be a screen for receiving input of a selection instruction indicating a model number of plain paper by using other input elements such as radio buttons and fields instead of the pull-down menu PMc. .. Further, the selection instruction may be received by another method without receiving the input of the selection instruction of the option indicating the color matching level and the observation angle θ on the UI screen. For example, if there is a tendency for the type of print medium used in each country, a return profile corresponding to the type of print medium corresponding to the country of shipment of the printer 200 may be selected. When there is a correlation between the observation angle θ and the adjustment amount for reducing the reciprocating color difference, in the second embodiment, the detailed setting screen WD2 of the first embodiment is displayed instead of the detailed setting screen WD2b. The level of color matching may be selected as an option, and internally, the return profile of the observation angle θ corresponding to the selected level may be selected.

(6) In each of the above embodiments, when plain paper is used as the printing medium, bidirectional printing is performed and a plurality of return profiles are used properly. Instead of this, even when other printing media such as glossy paper, wood-free paper, and OHP sheet are used, a plurality of return profiles may be used properly when bidirectional printing is performed.

(7) The arrangement position of each nozzle row of the print head 110 does not have to be the order of the nozzle rows NY, NM, NC, NK from the upstream side in the X direction of FIG. 2 (B), and any other order. May be adopted. If the color difference occurs due to the different printing directions, the nozzle rows may be arranged so as to be symmetrical with respect to the printing direction.

(8) In the printing mechanism 100 of the above embodiment, the transport unit 140 transports the paper M to move the paper M relative to the print head 110 in the transport direction. Instead of this, the paper M may be moved relative to the print head 110 in the transport direction by moving the print head 110 in the direction opposite to the transport direction with respect to the fixed paper M.

(9) In each of the above embodiments, the device that executes the image processing of FIG. 7 is the terminal device 300. Instead of this, the CPU 210 of the printer 200 may execute the image processing of FIG. 7 as an image processing device. In this case, the CPU 210 that functions as an image processing device displays the UI screen of FIG. 6 and the like on its own display unit 270. Further, in S360 of FIG. 8, the CPU 210 outputs the partial print data and the direction information to, for example, a predetermined memory area of the non-volatile storage device 220 or the volatile storage device 230. The printing mechanism 100 of the printer 200 executes partial printing according to the partial printing data and direction information output to the memory area.

As can be seen from the above description, in each of the above embodiments, the terminal device 300 is an example of an image processing device, and the printer 200 is an example of a print execution unit. In this modification, the CPU 210 of the printer 200 is an example of an image processing device, and the printing mechanism 100 of the printer 200 is an example of a print execution unit.

Further, the device that executes the image processing of FIG. 7 may be, for example, a server that acquires image data from a printer or a terminal device and generates a print job using the image data. In this case, the printer or terminal device executes the acquisition of information indicating the display of the UI screens of S100 to S110 of FIG. 7 and the print settings (including, for example, the selection instruction of the color matching level), and the printer or terminal. The device sends information indicating the print setting to the server together with the image data. Such a server may be a plurality of computers capable of communicating with each other via a network. In this case, an entire plurality of computers capable of communicating with each other via a network is an example of an image processing device.

(10) In each of the above embodiments, a part of the configuration realized by the hardware may be replaced with software, and conversely, a part or all of the configuration realized by the software may be replaced with the hardware. You may do so. For example, when the image processing of FIG. 7 is executed in the printer 200, the color conversion processing and the halftone processing are realized by, for example, a dedicated hardware circuit (for example, ASIC) that operates according to the instruction of the CPU 210 of the printer 200. You may.

Although the present invention has been described above based on Examples and Modifications, the above-described embodiments of the invention are for facilitating the understanding of the present invention and do not limit the present invention. The present invention can be modified and improved without departing from the spirit and claims, and the present invention includes equivalents thereof.

10a to 10g ... Spectral colorimeter, 20 ... Light source, 100 ... Printing mechanism, 110 ... Printing head, 111 ... Nozzle forming surface, 120 ... Head drive unit, 130 ... Main scanning unit, 133 ... Carriage, 134 ... Sliding shaft , 140 ... Conveyor, 141 ... Downstream roller pair, 142 ... Upstream roller pair, 145 ... Paper stand, 200 ... Printer, 210 ... CPU, 220 ... Non-volatile storage device, 230 ... Volatile storage device, 231 ... Buffer area, 260 ... Operation unit, 270 ... Display unit, 280 ... Communication unit, 300 ... Terminal device, 310 ... CPU, 320 ... Non-volatile storage device, 330 ... Volatile storage device, 331 ... Buffer area, 360 ... Operation unit, 370 ... Display unit, 380 ... communication unit, 1000 ... printing system, M ... paper, NM ... nozzle row, FP ... outbound profile, NW ... network, NY, NC, NM, NK ... nozzle row, NZ ... nozzle, Ik ... ink, WD1 ... Main screen, WD2, WD2b, WD2c ... Detailed setting screen, PG1, PG2 ... Computer program, PM1-PM3, PMc ... Pull-down menu, RP1-RP4 ... Return profile, SB, SBb ... Slide bar

Claims (8)

A printing head having a first-class nozzle that ejects first-class ink and a second-class nozzle that ejects second-class ink at a position different from that of the first-class nozzle in the main scanning direction. And the main scanning unit that executes the main scanning that moves the print head along the main scanning direction with respect to the printing medium, and the printing medium in the sub-scanning direction that intersects the main scanning direction with respect to the printing head. A print execution unit including a sub-scanning unit that executes a sub-scanning that moves a print head, and a partial printing that forms dots on the printing medium by the print head while performing the main scanning, and the sub-scanning. An image processing device for the print execution unit that prints by executing a plurality of times.
A plurality of colors defining a correspondence relationship between a first-class color value and a second-class color value including a component value corresponding to a plurality of types of inks including the first-class ink and the second-class ink. The plurality of profiles are a storage unit for storing one profile for the first direction corresponding to the first direction along the main scanning direction, and a second profile opposite to the first direction. The storage unit, which includes a plurality of profiles for the second direction corresponding to the directions.
A profile selection unit that selects the second direction profile to be used from the plurality of second direction profiles based on the specific information.
An image acquisition unit that acquires target image data including a plurality of the first type color values corresponding to the plurality of pixels, and an image acquisition unit.
Using the target image data, the first partial print data for the partial print performed in the first direction, the second partial print data for the partial print performed in the second direction, and A print data generation unit that executes a generation process for generating a plurality of partial print data including the above, and the generation process uses each of the plurality of first-class color values included in the target image data. The print data generation unit, which includes a color conversion process for converting to a second type of color value,
A print control unit that causes the print execution unit to print a print image based on the target image data by causing the print execution unit to execute the partial print a plurality of times using the plurality of partial print data.
With
Each of the plurality of second-direction profiles is based on the second-type color value obtained by converting a specific first-class color value using the first-direction profile. The second part is based on the image printed by the partial printing of the above and the color value of the second type obtained by converting the specific color value of the first type using the profile for the second direction. It has been adjusted to reduce the color difference between the printed image and the printed image.
The plurality of profiles for the second direction differ from each other in the degree of expected color difference.
The print data generation unit
The first partial print data is generated by executing the first generation process including the first color conversion process executed by using the first direction profile.
The second partial print data is generated by executing the second generation process including the second color conversion process executed by using the second direction profile selected by the profile selection unit. , Image processing equipment. The image processing apparatus according to claim 1.
The plurality of second-direction profiles include the first second-direction profile and the second second-direction profile.
The image processing device further
It is provided with an instruction acquisition unit that acquires a selection instruction of one option from a plurality of options including the first option and the second option as the specific information from the user.
The profile selection unit
When the selection instruction for selecting the first option is acquired, the profile for the first second direction is selected, and the profile is selected.
An image processing device that selects a profile for the second second direction when a selection instruction for selecting the second option is acquired. The image processing apparatus according to claim 2.
The first option is an option indicating that the level at which the color of the image printed by the second partial printing is adjusted is the first level.
The second option is an image processing apparatus that indicates that the level at which the color of the image printed by the second partial printing is adjusted is a second level higher than the first level. The image processing apparatus according to claim 2.
The first option is an option indicating that the print medium used for printing is a type 1 print medium.
The second option is an image processing apparatus that indicates that the print medium used for printing is a second type print medium different from the first type print medium. The image processing apparatus according to claim 2.
The first option is an option indicating that the observation angle, which is the angle of the line of sight with respect to the printed print medium assumed at the time of observation, is the first angle.
The second option is an image processing apparatus that indicates that the observation angle assumed at the time of observation is a second angle different from the first angle. The image processing apparatus according to any one of claims 1 to 4.
The plurality of second-direction profiles include the first second-direction profile and the second second-direction profile.
In the first profile for the second direction, the color of the image printed by the second partial printing on the printing medium of the first type using the test image data is the color of the image printed using the test image data. It is a profile adjusted so as to approach the color of the image printed by the first partial printing on one type of printing medium.
In the second second direction profile, the color of the image printed by the second partial printing on the second printing medium different from the first type printing medium using the test image data is An image processing apparatus, which is a profile adjusted by using the test image data so as to approach the color of an image printed on the second type printing medium by the first partial printing. The image processing apparatus according to any one of claims 1 to 5.
The plurality of second-direction profiles include the first second-direction profile and the second second-direction profile.
In the first profile for the second direction, the color observed when the image printed on the print medium by the second partial printing using the test image data is observed at the first angle is the color. It is a profile adjusted so as to approach the color observed when observing the image printed on the print medium by the first partial printing using the test image data at the first angle.
The second profile for the second direction observes an image printed on the print medium by the second partial printing using the test image data at a second angle different from the first angle. So that the color observed in the case approaches the color observed when the image printed on the print medium by the first partial printing using the test image data is observed at the second angle. Adjusted profile,
The image processing apparatus, wherein the first angle and the second angle are angles of line of sight with respect to the printed print medium. A printing head having a first-class nozzle that ejects first-class ink and a second-class nozzle that ejects second-class ink at a position different from that of the first-class nozzle in the main scanning direction. And the main scanning unit that executes the main scanning that moves the print head along the main scanning direction with respect to the printing medium, and the printing medium in the sub-scanning direction that intersects the main scanning direction with respect to the printing head. A print execution unit including a sub-scanning unit that executes a sub-scanning that moves a print head, and a partial printing that forms dots on the printing medium by the print head while performing the main scanning, and the sub-scanning. A computer program for a control device of the print execution unit that prints by executing it a plurality of times.
The control device has a correspondence relationship between a color value of the first type and a color value of the second type including a component value corresponding to the ink of the first type and a plurality of types of inks including the ink of the second type. A storage unit for storing a plurality of profiles, wherein the plurality of profiles include one profile for the first direction corresponding to the first direction along the main scanning direction, and the first direction. Includes said storage including a plurality of second direction profiles corresponding to opposite second directions.
The computer program
A profile selection function for selecting the second direction profile to be used from the plurality of second direction profiles based on specific information, and
An image acquisition function for acquiring target image data including a plurality of the first type color values corresponding to the plurality of pixels, and an image acquisition function.
Using the target image data, the first partial print data for the partial print performed in the first direction, the second partial print data for the partial print performed in the second direction, and It is a print data generation function that executes a generation process for generating a plurality of partial print data including the above, and the generation process sets each of the plurality of first type color values included in the target image data. The print data generation function including a color conversion process for converting to a second type of color value, and
A print control function for causing the print execution unit to print a print image based on the target image data by causing the print execution unit to execute the partial print a plurality of times using the plurality of partial print data.
Is realized in the computer mounted on the control device,
Each of the plurality of second-direction profiles is based on the second-type color value obtained by converting a specific first-class color value using the first-direction profile. The second part is based on the image printed by the partial printing of the above and the color value of the second type obtained by converting the specific color value of the first type using the profile for the second direction. It has been adjusted to reduce the color difference between the printed image and the printed image.
The plurality of profiles for the second direction differ from each other in the degree of expected color difference.
The print data generation function is
The first partial print data is generated by executing the first generation process including the first color conversion process executed by using the first direction profile.
The second partial print data is generated by executing the second generation process including the second color conversion process executed by using the second direction profile selected by the profile selection unit. , Computer program.

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