JP2011131429A - Control device and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique in which an image of a high image quality can be formed using processed image data compensated for the variability of discharging amounts. <P>SOLUTION: In order to compensate for the variability of the discharging amounts of liquid droplets discharged from a plurality of nozzles, a control unit of a PC carries out a specific process (S33) to a target pixel in image data of an object using correction data for a target nozzle which forms a dot at a position on a print medium corresponding to the target pixel. The correction data is data obtained using characteristic data corresponding to the target nozzle and detection results of temperatures of a printing head. The characteristic data is data related to the discharging amount of liquid droplets discharged from the target nozzle. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present specification discloses a technique for causing a print execution unit including a print head formed with a plurality of nozzles for discharging droplets to execute printing.

  Many ink jet printers perform binary (no dots, with dots) or ternary by performing image processing (for example, halftone processing) on CMYK image data including a plurality of pixels described in the CMYK format. Processed image data including a plurality of pixels described above (no dots, small dots, medium dots, large dots, etc.) is generated. The ink jet printer forms dots for each of a plurality of pixels in the processed image data at positions on the print medium corresponding to the pixels according to the values of the pixels. As a result, an image represented by the processed image data is formed on the print medium.

  The ink jet printer of Patent Document 1 stores, for each of a plurality of nozzles formed on a print head, characteristic data related to the ejection amount of ink droplets ejected from the nozzles. Specifically, the characteristic data is data indicating what percentage of increase / decrease with respect to a predetermined target discharge amount. This ink jet printer corrects the CMYK image data using the characteristic data of each nozzle before executing image processing. For example, when the K value of a specific pixel in the CMYK image data is K and the characteristic data of the nozzle that forms a dot at a position on the print medium corresponding to the specific pixel is X%, K The K value of the specific pixel is corrected by a calculation formula of × (100% −X%). The above correction is executed for each pixel in the CMYK image data. The ink jet printer performs image processing on the corrected CMYK image data. As a result, processed image data is generated in which variations in the ejection amount of ink droplets ejected from a plurality of nozzles (hereinafter sometimes simply referred to as “variations in ejection amount”) are compensated.

JP 2000-25212 A JP-A-11-58704 JP 2001-38892 A JP 2005-225199 A

  There is a need to improve the image quality of images printed on print media. The present specification provides a technique capable of printing a high-quality image.

  The technology disclosed in this specification is a control device for causing a print execution unit including a print head formed with a plurality of nozzles for discharging droplets to execute printing. The control device includes an image processing unit and a supply unit. The image processing unit generates processed image data by performing image processing on specific image data. The supply unit supplies the processed image data to the print execution unit. In order to compensate for variations in the discharge amount of the liquid droplets ejected from the plurality of nozzles, the image processing unit performs a position on the print medium corresponding to the target pixel with respect to the target pixel in the target image data. A specific process is executed using the correction data for the nozzle of interest that forms dots. The correction data is data obtained by using the target characteristic data corresponding to the target nozzle among the plurality of characteristic data corresponding to the plurality of nozzles and the print head temperature detection result. The characteristic data is data related to the ejection amount of droplets ejected from the corresponding nozzle.

  The discharge amount of the liquid droplets discharged from the nozzles changes according to the temperature of the print head. The control device executes compensation processing (the specific processing described above) for compensating for variations in the ejection amount, using correction data that takes into account changes in the ejection amount due to temperature changes of the print head. . For this reason, it is possible to generate processed image data in which the variation in the ejection amount is more appropriately compensated as compared with the method of executing the compensation process without considering the temperature of the print head. Since the processed image data is supplied to the print execution unit, the print execution unit can print a high-quality image on the print medium using the processed image data.

  The image processing unit may include a detection result acquisition unit, a data acquisition unit, and a correction data calculation unit. The detection result acquisition unit may acquire a detection result of the temperature of the print head. The data acquisition unit may acquire attention characteristic data corresponding to the attention nozzle from a table in which the plurality of characteristic data is registered. The correction data calculation unit may calculate correction data for the target nozzle using the target characteristic data corresponding to the target nozzle and the temperature detection result of the print head.

  Each of the plurality of characteristic data corresponding to the plurality of nozzles is the first type of data related to the ejection amount of the droplets ejected from the corresponding nozzle when the print head is at the first temperature. And when the print head is at the second temperature, the second type of data relating to the ejection amount of the droplet ejected from the corresponding nozzle may be included. The correction data calculation unit detects the first type of data included in the target characteristic data corresponding to the target nozzle, the second type of data included in the target characteristic data corresponding to the target nozzle, and the temperature detection result of the print head. And the correction data for the nozzle of interest may be calculated. As described above, by using the first type data and the second type data included in the characteristic data, it is possible to calculate correction data suitable for the temperature of the print head.

  Alternatively, each of the plurality of characteristic data corresponding to the plurality of nozzles is a first type related to a discharge amount of droplets discharged from the corresponding nozzle when the print head is at the first temperature. And the second type data related to the ejection amount of the droplets ejected from the corresponding nozzle when the print head is at the second temperature using the first type data And a correction value. The correction data calculation unit uses the first type data included in the target characteristic data corresponding to the target nozzle, the correction value, the print head temperature detection result, and the change rate, and uses the target nozzle. Correction data for the above may be calculated. As described above, correction data suitable for the temperature of the print head can be calculated using the first type data and the correction value included in the characteristic data.

  The print execution unit may be operable in the first print mode and the second print mode. In the first print mode, the print head may perform the first number of main scans to print the image represented by the specific image data on the print medium at the first print resolution. In the second print mode, the print head performs a second number of main scans that is greater than the first number of times, whereby an image represented by the specific image data is printed at a second print resolution. You may print on. The second print resolution may be higher than the first print resolution or the same print resolution as the first print resolution. The image processing unit corrects the target nozzle obtained using the target characteristic data corresponding to the target nozzle and the temperature detection result of the print head when the print execution unit operates in the first print mode. A specific process may be executed using the business data. When the print execution unit operates in the second print mode, the image processing unit performs other processing for the target nozzle obtained using the target characteristic data corresponding to the target nozzle without using the temperature detection result of the print head. The above-described specific processing may be executed using the correction data. In the case of the second printing mode, density unevenness due to variations in the discharge amount of the nozzles is usually less noticeable than in the case of the first printing mode. In view of such knowledge, the control device described above does not execute the compensation process in which the detection result of the print head temperature is used in the second print mode. According to this configuration, it is possible to reduce the processing load of the control device as compared with a technique of executing compensation processing in which the detection result of the print head temperature is used in the second print mode.

  The image processing unit may include a color conversion processing unit and a halftone processing unit. The color conversion processing unit performs color conversion processing on each pixel in the specific image data expressed in the first type color space, thereby expressing the second color space. The target image data may be generated. The halftone processing unit may generate processed image data by performing halftone processing on the target image data. The halftone processing unit may include a correction unit, a determination unit, and an error value calculation unit. The correction unit generates a corrected value by correcting the value of the target pixel in the target image data using a plurality of error values corresponding to a plurality of neighboring pixels in the vicinity of the target pixel. May be. The determination unit may determine whether to form a dot at a position on the print medium corresponding to the target pixel based on the corrected value and the threshold corresponding to the target pixel. The error value calculation unit may calculate an error value corresponding to the target pixel according to the determination regarding whether or not to form a dot for the target pixel. The error value calculation unit calculates the error value corresponding to the target pixel using the corrected value and the correction data when it is determined to form a dot for the target pixel. Processing may be executed.

  The target image data may be the specific image data. The image processing unit may include a color conversion processing unit and a halftone processing unit. The color conversion processing unit performs the specific processing including the color conversion processing and the correction processing on each pixel in the target image data expressed in the first type color space, Color-converted image data expressed in the second type color space may be generated. The halftone processing unit may generate processed image data by performing halftone processing on the color-converted image data. The color conversion processing unit generates a color-converted pixel expressed in the second type color space by performing color conversion processing on the target pixel in the target image data. A corrected pixel may be generated by executing a correction process on the color-converted pixel using the correction data in a kind of color space.

  A control method and a computer program for realizing the above printer are also new and useful.

The structure of a network system is shown. The top view of the nozzle surface of a print head is shown. A characteristic data table is shown. The relationship between the ink droplet ejection amount and the print head temperature is shown for each K nozzle. The raster group formed in the first printing mode is shown. A mode that a printing medium is conveyed in the 2nd printing mode is shown. The raster group formed in the second printing mode is shown. The flowchart of the binary data generation process which PC performs is shown. Each pixel in the converted RGB image data is shown. Each pixel in CMYK image data is shown. The error value of each pixel in CMYK image data is shown. An equation for calculating an error value of each pixel in CMYK image data is shown. The flowchart of the binary data generation process which PC of 2nd Example performs is shown. Each pixel in the corrected image data produced | generated in 2nd Example is shown. The raster group formed in the 3rd printing mode of 3rd Example is shown. The change rate data table of 4th Example is shown.

(First embodiment)
(System configuration)
A first embodiment will be described with reference to the drawings. FIG. 1 shows a schematic diagram of a network system 2 of the present embodiment. The network system 2 includes a LAN 4, a PC 10, and a printer 50. The PC 10 and the printer 50 are connected to the LAN 4. The PC 10 and the printer 50 can communicate with each other via the LAN 4.

(Configuration of PC10)
The PC 10 includes an operation unit 12, a display unit 14, a network interface 16, a storage unit 20, and a control unit 30. The operation unit 12 includes a mouse and a keyboard. The user can input various instructions to the PC 10 by operating the operation unit 12. The display unit 14 is a display for displaying various information. The network interface 16 is connected to the LAN 4.

  The storage unit 20 includes a work area 22. For example, the work area 22 stores data to be printed. The data to be printed may be, for example, data generated by an application in the PC 10 or data acquired from an external device. Examples of applications in the PC 10 include word processing software and spreadsheet software. Examples of the external device include a server on the Internet, a device connected to the LAN 4, and a portable storage medium. The storage unit 20 further stores a printer driver 24 for the printer 50. The printer driver 24 is software for transmitting various instructions (for example, print instructions) to the printer 50. For example, the printer driver 24 may be installed in the PC 10 from a computer-readable medium storing the printer driver 24, or may be installed in the PC 10 from a server on the Internet.

  The control unit 30 executes various processes according to a program (for example, the printer driver 24) stored in the storage unit 20. When the control unit 30 executes processing according to the printer driver 24, the functions of the image processing unit 32 and the supply unit 48 are realized. The image processing unit 32 includes a color conversion processing unit 34, a data acquisition unit 36, a correction data calculation unit 38, a halftone processing unit 40, and a detection result acquisition unit 47. The halftone processing unit 40 includes a correction unit 42, a determination unit 44, and an error value calculation unit 46.

(Configuration of printer 50)
The printer 50 includes a network interface 52, a display unit 54, a storage unit 56, and a print execution unit 70. The network interface 52 is connected to the LAN 4. The display unit 54 is a display for displaying various information. The print execution unit 70 prints an image represented by binary data supplied from the PC 10 on a print medium according to the program 64 stored in the storage unit 56. The print execution unit 70 includes a temperature detection unit 72 and a print head 80. The temperature detector 72 detects the temperature of the print head 80. In this embodiment, the temperature detection unit 72 is a temperature sensor directly attached to the print head 80. In addition to the above, the print execution unit 70 includes a drive mechanism for the print head 80, a print medium transport mechanism, and the like (these are not shown).

  The drive mechanism of the print head 80 includes a carriage and a motor that moves the carriage. The print head 80 is detachably mounted on the carriage. The carriage reciprocates in a predetermined direction within the housing of the printer 50. When the carriage moves, the print head 80 also moves. The reciprocating direction of the carriage, that is, the reciprocating direction of the print head 80 is referred to as “main scanning direction”. In this embodiment, the printing head 80 reciprocating once is referred to as “one main scanning”. The drive mechanism of the print head 80 further includes a circuit that supplies a drive signal to the print head 80. When a drive signal is supplied to the print head 80, ink droplets are ejected from the nozzle group 84k and the like (see FIG. 2) formed on the print head 80. In the present embodiment, a drive signal is supplied to the print head 80 so that ink droplets are ejected from the nozzle group 84k or the like during one outward main scanning path. Note that ink droplets are not ejected from the nozzle group 84k or the like during a single main scanning return pass. The print medium transport mechanism transports the print medium in a direction perpendicular to the main scanning direction. The direction in which the print medium is conveyed is referred to as “sub-scanning direction”. In another embodiment, a drive signal is supplied to the print head 80 such that ink droplets are ejected from the nozzle group 84k or the like during both the forward and backward passes of the print head 80 once. May be. In this case, out of one reciprocation of the print head 80, each of the forward path and the return path can be referred to as “one main scan”. Further, the drive signal supplied to the print head 80 is changed according to the detection result of the temperature detection unit 72.

  As shown in FIG. 2, the print head 80 includes three sets of nozzle groups 84c, 84m, and 84y for ejecting ink droplets of three kinds of chromatic colors (cyan, magenta, and yellow), and black ink droplets. A nozzle surface 82 on which a set of nozzle groups 84k for discharging is formed is provided. The K nozzle group 84k includes n (n is an integer of 2 or more) K nozzles. The K nozzle group 84k forms six nozzle rows Lk1 to Lk6 extending in the sub-scanning direction. The n K nozzles in the K nozzle group 84k belong to one of the six nozzle rows Lk1 and the like. For example, the K nozzles Nk1, Nk7, etc. belong to the nozzle row Lk1, the K nozzle Nk4, etc. belong to the nozzle row Lk2, and the K nozzle Nk2, etc. belong to the nozzle row Lk3. Between two adjacent K nozzles belonging to one nozzle row (for example, the K nozzle Nk1 and the K nozzle Nk7 belonging to the nozzle row Lk1), the other five nozzle rows are arranged in the sub-scanning direction. Five nozzles for K (for example, NK2 to NK6) are located. In the present specification, “Nk1” is used as the reference number of the K nozzle existing in the most downstream side (upper side in FIG. 2) in the sub-scanning direction in the K-nozzle group 84k. The reference number of the nozzle for K increases (for example, Nk2, Nk3,...) Toward the upstream side (lower side in FIG. 2).

  The nozzle groups 84c and the like corresponding to other colors have the same configuration as the K nozzle group 84k. Accordingly, a total of 4n nozzles are formed on the nozzle surface 82. Hereinafter, all the nozzles that eject ink droplets of four colors of CMYK are referred to as “4n nozzles”. Reference numbers are set for the nozzle groups 84c and the like of the other colors as in the case of the K nozzle group 84k. Since the four nozzle groups 84k and the like have the same configuration, the four nozzles corresponding to the four colors CMYK are arranged at the same position in the sub-scanning direction. For example, in the sub scanning direction, four nozzles Nk1, Nc1, Nm1, and Ny1 are arranged at the same position, and four nozzles Nk2, Nc2, Nm2, and Ny2 are arranged at the same position.

  The storage unit 56 stores a characteristic data table 60 and a program 64. The program 64 includes a program for printing executed by the print execution unit 70. As shown in FIG. 3, the characteristic data table 60 includes 4n characteristic data corresponding to 4n nozzles formed in the print head 80. Each of the 4n pieces of characteristic data includes three types of temperature characteristic data (for example, Nk1) related to the nozzle number (for example, Nk1) of the nozzle corresponding to the characteristic data and the ejection amount of the ink droplet ejected from the nozzle. Includes “6”, “4”, and “2”). The three types of temperature characteristic data include temperature characteristic data related to the ejection amount when the temperature of the print head 80 is 10 ° C. (for example, “6” of Nk1) and the temperature when the temperature of the print head 80 is 25 ° C. Temperature characteristic data related to the discharge amount (for example, “4” of Nk1) and temperature characteristic data related to the discharge amount when the temperature of the print head 80 is 40 ° C. (for example, “2” of Nk1). . In the characteristic data table 60 of FIG. 3, the reference number of the nozzle (Nk1 in FIG. 2, etc.) is adopted as the nozzle number of the nozzle. For example, the characteristic data “6, 4, 2” corresponding to the nozzle number Nk1 indicates the characteristic data of the K nozzle Nk1 (see FIG. 2) for ejecting black ink droplets. Each characteristic data registered in the characteristic data table 60 is examined in advance by the vendor of the printer 50. Specifically, it is investigated by the following method.

  Although not shown, the print head 80 includes an actuator unit for ejecting ink droplets from 4n nozzles. The actuator unit includes 4n individual electrodes corresponding to 4n nozzles. When the drive signal is supplied to the individual electrode, one ink droplet is ejected from the nozzle corresponding to the individual electrode. The vendor of the printer 50 first corresponds to n K nozzles belonging to the K nozzle group 84k in the first environment in which the temperature detection unit 72 for detecting the temperature of the print head 80 detects 10 ° C. One drive signal is supplied to each of the n individual electrodes. Note that the n drive signals supplied here are the same signal. When the n drive signals are supplied, n black ink droplets are ejected from the n K nozzles toward the first medium. As a result, n black dots corresponding to the n K nozzles are formed on the first medium.

  In the first environment, the vendor determines the density of a specific black dot having the lowest density in the K nozzle group 84k to be “255” which is the maximum value of 256 gradations. Next, the vendor specifies the density of dots formed by other K nozzles based on the density of a specific black dot having the lowest density. For this reason, the density of dots formed by other K nozzles is specified by a value of 255 or more. Subsequently, the vendor determines the temperature corresponding to 10 ° C. of the K nozzle based on the difference between the density of the dot formed by each K nozzle and the density of the specific dot having the lowest density (ie, 255). Determine characteristic data. For this reason, in this embodiment, the temperature characteristic data corresponding to 10 ° C. of the K nozzle that forms the specific dot having the lowest density is determined to be zero. The temperature characteristic data corresponding to 10 ° C. of the other K nozzles is determined to be a value of zero or more. For example, in the characteristic data corresponding to the nozzle number Nk1 shown in FIG. 3, the temperature characteristic data at 10 ° C. is “6”. This means that the difference between the density (261) of the dots formed by the K nozzle Nk1 in the first environment and the density (255) of the specific black dot is “6”. .

  Similarly, the vendor determines the detection result of the temperature detection unit 72 in each of the second environment in which the temperature detection unit 72 detects 25 ° C. and the third environment in which the temperature detection unit 72 detects 40 ° C. The corresponding drive signal is supplied. As a result, in the second environment, a second medium in which n black dots corresponding to n K nozzles are formed is obtained, and in the third environment, n K nozzles are supported. A third medium in which n black dots are formed is obtained. Similarly, the vendor determines temperature characteristic data corresponding to the temperature of each of the second and third environments. That is, in each of the second and third environments, a specific black dot having the lowest density among the n black dots formed in the environment is specified, and the above-mentioned specific black dot is selected. The temperature characteristic data corresponding to the temperature of the environment of the K nozzle to be formed is determined to be zero. Next, for each of the other n−1 black dots, the vendor selects a temperature corresponding to the temperature of the environment based on the difference between the density of the dot and the density of the specific black dot. Determine characteristic data.

  FIG. 4 shows the measurement results obtained by measuring the density of the 3n black dots formed in the first to third environments (for example, the density of black per unit area). The horizontal axis corresponds to the nozzle number of each K nozzle included in the K nozzle group 84k. The vertical axis corresponds to the dot density, that is, the ink droplet ejection amount. The graph with the symbol Ga shows the measurement result in the first environment (10 ° C.), the graph with the symbol Gb shows the measurement result in the second environment (25 ° C.), and the graph with the symbol Gc shows the measurement result. The measurement result in the 3rd environment (40 degreeC) of is shown. As is apparent from FIG. 4, as a general tendency, the lower the temperature of the print head 80, the larger the difference between the maximum discharge amount and the minimum discharge amount (difference between the maximum value and the minimum value on the graph). Turned out to be.

  The vendor determines the characteristic data of each nozzle for each of cyan, magenta, and yellow, as in the case of black. For example, the vendor causes cyan ink droplets to be ejected from the C nozzle group 84c in each of the first to third environments. Thereby, 3n dots are formed. For each of the first to third environments, the vendor specifies a specific dot having the lowest density among n dots formed in the environment, and sets the specific dot in the environment in which the specific dot is formed. The corresponding temperature characteristic data is determined to be zero. Further, for each of the other n−1 dots, the vendor sets temperature characteristic data corresponding to the temperature of the environment based on the difference between the density of the dot and the density of the specific cyan dot. Decide. The vendor generates a characteristic data table 60 based on the investigation result, and stores the characteristic data table 60 in the storage unit 56. The printer 50 has already stored the characteristic data table 60 at the shipping stage.

(About print mode)
Next, the print mode in which the print execution unit 70 of the printer 50 can operate will be described. The image processing unit 32 (see FIG. 1) of the PC 10 generates binary data by executing binary data generation processing (see FIG. 8) described later. The image processing unit 32 generates binary data corresponding to the first print resolution when the first print resolution (for example, 300 dpi) is designated by the user. On the other hand, the image processing unit 32 of the PC 10 generates binary data corresponding to the second print resolution when a second print resolution (for example, 600 dpi) higher than the first print resolution is designated by the user. To do. The supply unit 48 (see FIG. 1) of the PC 10 transmits the binary data generated by the image processing unit 32 to the printer 50. The print execution unit 70 of the printer 50 operates in the first print mode when binary data corresponding to the first print resolution is supplied from the PC 10. On the other hand, the print execution unit 70 operates in the second print mode when binary data corresponding to the second print resolution is supplied from the PC 10.

(First print mode)
Pk1, Pk2, etc. shown in FIG. 5 project the K nozzles Nk1, Nk2, etc. constituting the K nozzle group 84k in the main scanning direction when the projection line PL extending along the sub-scanning direction is set. The projection point obtained by this is shown. The print execution unit 70 ejects ink droplets from the K nozzles Nk1 and the like based on the binary data during one main scan of the print head 80. As a result, for example, a plurality of black dots arranged along the main scanning direction are formed on the print medium by the plurality of black ink droplets ejected from the K nozzle Nk1. Similarly, a plurality of black dots arranged in the main scanning direction are formed on the print medium by the plurality of black ink droplets ejected from the K nozzle Nk2. In the case of monochrome printing, the arrangement of a plurality of black dots formed by one K nozzle in one main scan of the print head 80 is referred to as “one raster”. . Therefore, each raster extends along the main scanning direction. In the case of monochrome printing, in one main scan of the print head 80, for example, seven K nozzles Nk1 to Nk7 form seven rasters R1 to R7.

  As described above, for example, the nozzle Nk1, the nozzle Nc1, the nozzle Nm1, and the nozzle Ny1 are arranged at the same position in the sub-scanning direction (see FIG. 2). Therefore, in the case of color printing, in one main scan of the print head 80, the four nozzles Nk1, Nc1, Nm1, and Ny1 form dots at the same position in the sub-scanning direction. Therefore, in the case of color printing, in one main scan of the print head 80, the arrangement of a plurality of CMYK dots formed by the four nozzles Nk1, Nc1, Nm1, and Ny1 is referred to as “one line”. This is called “raster”.

  In the first printing mode, n rasters arranged in the sub-scanning direction are formed in the first main scanning of the print head 80. When the first main scan of the print head 80 is completed, the print execution unit 70 executes conveyance of the print medium. In the first printing mode, the first distance is adopted as the transport distance here. The first distance is a distance corresponding to n nozzle pitches. One nozzle pitch is a distance between two adjacent nozzles (for example, Nk1 and Nk2) in the sub-scanning direction. That is, one nozzle pitch is a distance between two adjacent projection points (for example, Pk1 and Pk2). Next, the print execution unit 70 executes the second main scan of the print head 80. As a result, n rasters are newly formed. The print execution unit 70 repeatedly executes a combination of conveyance of the first distance of the print medium and main scanning of the print head 80. As a result, the image represented by the binary data is printed on the print medium.

  As is clear from the above description, in the first printing mode, the distance between two adjacent rasters is approximately one nozzle pitch. The first print resolution means a print resolution in the sub-scanning direction. That is, the first print resolution can be rephrased as “print resolution in which the distance between two adjacent rasters is approximately one nozzle pitch”.

(Second print mode)
The second print mode will be described by taking the case of monochrome printing as an example. As shown in FIG. 6, in the second print mode, the print execution unit 70 first performs the first main scan of the print head 80 so that printing is executed on the portion 152 of the print medium 150. Execute. The portion 152 is a portion of the print medium 150 that is located on the most downstream side in the sub-scanning direction. For example, when n is an odd number, in the first main scanning, among the n K nozzles Nk1 and the like, they exist on the upstream side in the sub-scanning direction (the lower side in FIG. 6) (n + 1) / 2. The K nozzles Nkm to Nkn form (n + 1) / 2 rasters on the portion 152. The “m” is (n + 1) / 2. In FIG. 7, eight K nozzles Nkm to Nkm + 7 out of (n + 1) / 2 K nozzles Nkm to Nkn by the first main scanning (projection points Pkm to Pkm + 7 are shown in FIG. 7). , 8 rasters Rm to Rm + 7 are formed.

  Next, the print execution unit 70 carries the print medium 150. In the second printing mode, the second distance is adopted as the transport distance here. For example, when n is an odd number, the second distance is a distance corresponding to n / 2 nozzle pitch. When this conveyance is executed, as shown in FIG. 7, each of the n / 2 K nozzles Nk1 to Nkm-1 existing on the downstream side (upper side in FIG. 6) in the sub-scanning direction is the first time. Are located between two adjacent rasters (for example, Rkm and Rkm + 1) formed by the main scanning. In this state, the print execution unit 70 executes the second main scan of the print head 80. Thus, each of the (n−1) / 2 K nozzles Nk1 to Nkm−1 is between two adjacent rasters formed in the portion 152 of the print medium 150 by the first main scanning. One raster is formed. FIG. 7 shows seven K nozzles Nk1 to Nk7 out of (n-1) / 2 K nozzles Nk1 to Nkm-1 in the second main scan (projection points Pk1 to Pk7 in FIG. 7). Shows the formation of seven rasters R1 to R7. In the second main scanning, the (n + 1) / 2 K nozzles Nkm to Nkn existing on the upstream side (lower side in FIG. 6) in the sub-scanning direction further include the portion 154 (in FIG. 6) of the print medium 150. (N + 1) / 2 rasters are formed on the top (see the middle figure). The part 154 is a part adjacent to the part 152 and is a part located on the upstream side of the part 152 in the sub-scanning direction.

  The print execution unit 70 repeatedly executes a combination of conveyance of the print medium 150 for the second distance and main scanning of the print head 80. Thus, for example, in the third main scan, each of the (n−1) / 2 K nozzles Nk1 to Nkm−1 is adjacent to the portion 154 of the print medium 150 formed by the second main scan. One raster is formed between the two rasters. In the third main scanning, (n + 1) / 2 K nozzles Nkm to Nkn are further provided on the portion 156 (see the rightmost drawing in FIG. 6) of the printing medium 150 (n + 1) / 2 rasters. Form. The part 156 is a part adjacent to the part 154 and is a part located on the upstream side of the part 154 in the sub-scanning direction. The print execution unit 70 repeatedly executes a combination of conveyance of the print medium at the second distance and main scanning of the print head 80. As a result, the image represented by the binary data is printed on the print medium. The second printing mode in the case of color printing is the same as that in the case of black and white printing except that the nozzle group 84c of other colors is used.

  As is clear from the above description, in the second print mode, the distance between two adjacent rasters is approximately ½ nozzle pitch. The second print resolution is a print resolution twice as high as the first print resolution in the sub-scanning direction. The second print resolution can be rephrased as “print resolution in which the distance between two adjacent rasters is approximately 1/2 nozzle pitch”. Hereinafter, printing corresponding to the second printing mode may be referred to as “interlaced printing”.

(Binary data generation processing of PC10)
Next, processing executed by the control unit 30 of the PC 10 will be described. The user can select desired data and apply an operation for printing an image represented by the data to the operation unit 12. The above operation includes an operation in which the user selects one print resolution from the first print resolution and the second print resolution. In the present embodiment, processing contents will be described on the assumption that image data in RGB bitmap format (hereinafter referred to as “RGB image data”) is selected by the user. When data in another format (for example, text data, image data in a bitmap format other than RGB, composite data of text and bitmap, etc.) is selected, the control unit 30 selects the data selected by the user. Is converted into RGB image data using a known method. When the above operation is executed, the control unit 30 executes the binary data generation process of FIG. 8 according to the printer driver 24.

  The image processing unit 32 acquires RGB image data and stores the RGB image data in the work area 22 (S10). Next, the control unit 30 transmits a predetermined command for acquiring the characteristic data table 60 stored in the printer 50 to the printer 50. The printer 50 transmits the characteristic data table 60 stored in the storage unit 56 to the PC 10 in accordance with the predetermined command. As a result, the control unit 30 acquires the characteristic data table 60 (S12). The control unit 30 stores the characteristic data table 60 in the work area 22.

  Next, the image processing unit 32 generates converted RGB image data by executing resolution conversion processing on the RGB image data using a known method (S14). In S14, the image processing unit 32 converts the RGB image data into a resolution corresponding to the print resolution selected by the user. That is, when the user selects the first print resolution, converted RGB image data corresponding to the first print resolution is generated, and when the user selects the second print resolution, The converted RGB image data corresponding to the print resolution of 2 is generated. The converted RGB image data 200 shown in FIG. 9 is obtained by the resolution conversion process. Each pixel 201, 202, 206, 207, etc. in the converted RGB image data 200 has an R value (for example, R (i, j)), a G value (for example, G (i, j)), and a B value (for example, B (i, j)). The R value, G value, and B value are multi-value data of 256 gradations (0 to 255), respectively. The x coordinate of the coordinates shown in each pixel indicates the column number of each pixel, and the y coordinate indicates the row number of each pixel.

  Next, the color conversion processing unit 34 (see FIG. 1) executes color conversion processing using a known method (S16). In S16, the color conversion processing unit 34 converts the converted RGB image data 200 into CMYK bitmap image data (hereinafter referred to as “CMYK image data”). The CMYK image data 210 shown in FIG. 10 is obtained by the color conversion process. One pixel (for example, the pixel 211) described in the CMYK format is obtained from one pixel (for example, the pixel 201) in the converted RGB image data 200. Therefore, the number of pixels of the CMYK image data 210 is equal to the number of pixels of the converted RGB image data 200. Each pixel 211, 212, 216, 217, etc. in the CMYK image data 210 has a C value (eg C (i, j)), an M value (eg M (i, j)), and a Y value (eg Y ( i, j)) and a K value (for example, K (i, j)). The C value, M value, Y value, and K value are multi-value data of 256 gradations (0 to 255), respectively. Moreover, the x coordinate of the coordinates shown in each pixel indicates the column number of each pixel, and the y coordinate indicates the row number of each pixel.

  Subsequently, the halftone processing unit 40 and the like (see FIG. 1) execute halftone processing using the CMYK image data 210. The halftone process includes the processes of S18 to S40. First, the correction unit 42 (see FIG. 1) specifies one pixel in the CMYK image data 210 (S18). The specific order of the pixels in S18 is determined in advance. Specifically, in the first processing of S18, the correction unit 42 includes one pixel belonging to the leftmost column among the plurality of pixels belonging to the uppermost row in FIG. Identify the pixels. In the process of S18 after the second time, the correction unit 42 is one pixel belonging to the same row as the pixel specified last time (hereinafter referred to as “previous specific pixel”), and is adjacent to the right of the previous specific pixel. One pixel belonging to this column is specified. When the previous specific pixel belongs to the rightmost column, the correction unit 42 selects one pixel belonging to the leftmost column among a plurality of pixels belonging to the row immediately below the row to which the previous specific pixel belongs. Identify the pixels.

  Hereinafter, one pixel specified in S18 is referred to as a “target pixel”. The correction unit 42 identifies one value (for example, K value) from the four CMYK values that constitute the pixel of interest (S20). Hereinafter, one value specified in S20 is referred to as “PV (Pixel Value)”. Subsequently, the correcting unit 42 corrects the PV specified in S20 (S22). More specifically, the correcting unit 42 calculates a plurality of neighboring pixels calculated in the vicinity of the target pixel from among the processed pixel group in which the processes of S20 to S36 have been completed before the target pixel. The PV of the target pixel is corrected using the individual error values. For example, when the target pixel is the pixel 216 in FIG. 11, the processing of S20 to S36 for the pixels 211 to 215 is completed. Therefore, for each of the pixels 211 to 215, four error values corresponding to CMYK have been calculated in S34 described later. For example, for the pixel 211, an error value corresponding to C, an error value corresponding to M, an error value corresponding to Y, and an error value corresponding to K have been calculated. In FIG. 11, for convenience of illustration, four error values corresponding to the four colors of CMYK are expressed as “ΔE” without being distinguished. Hereinafter, for example, an error value corresponding to K may be expressed as “ΔEk”. In the present embodiment, the four pixels 211, 212, 213, and 215 positioned on the upper left, upper, upper right, and left of the target pixel 216 are employed as the neighboring pixels of the target pixel 216. In another embodiment, as the neighboring pixel of the target pixel 216, the pixel on the left of the pixel 211, the pixel on the pixel 212, the pixel 214 on the left of the pixel 215, and the like may be employed.

  The correction unit 42 calculates four error values ΔE (i−1, j−1) that have been calculated for one neighboring pixel 211 out of the four neighboring pixels 211, 212, 213, and 215 of the target pixel 216. One error value (for example, an error value ΔEk (i−1, j−1) corresponding to K) corresponding to the current PV color (for example, K) is specified from the inside. For each of the other three neighboring pixels 212, 213, and 215, one error corresponding to the current PV color to be corrected is selected from the four error values calculated for the neighboring pixels. As a result, four error values corresponding to the current PV color to be corrected are specified, and then the correction unit 42 uses the specified four error values as shown in FIG. The PV of the pixel of interest 216 is compensated according to the mathematical formula shown in By correcting, the corrected value PV ′ is calculated, where s1, s2, s3, and s4 in the formula are determined in advance according to the positional relationship between the target pixel 216 and each neighboring pixel. For example, when PV (i, j) of the pixel of interest 216 is a K value (K (i, j)), the correction unit 42 has four neighboring pixels 211, 212, 213, For each of 215, an error value ΔEk of the neighboring pixel (for example, ΔEk (i−1, j−1) of the neighboring pixel 211), a coefficient corresponding to the neighboring pixel (for example, s1 corresponding to the neighboring pixel 211), Then, the correcting unit 42 multiplies the K value (i, j) (ie, PV (i, j)) of the pixel of interest 216 and the four neighboring pixels 211, 212, 4 multiplication values calculated for 213 and 215 And the corrected value K ′ (i, j) (that is, PV ′ (i, j)) is calculated.

  Subsequently, the determination unit 44 (see FIG. 1) determines that the corrected value PV ′ (for example, K ′ (i, j)) obtained in S22 is larger than a predetermined threshold Th (for example, 128). It is determined whether or not (S24). In the case of YES here, the determination unit 44 determines to form a dot of a color corresponding to the corrected value PV ′ to be determined on the print medium. Next, the determination unit 44 stores the value of the new pixel at the same position in the work area 22 (S26). The value stored here is the dot output value “1” of the color corresponding to the corrected value PV ′. For example, when the corrected value PV ′ of the target pixel 216 is K ′ (i, j), in S26, the determination unit 44 sets “K = 1” as the value of the new pixel at the same position as the target pixel. Is stored in the work area 22. When binary data including such information is supplied to the printer 50, black ink droplets are ejected toward the position on the print medium corresponding to the target pixel 216. That is, black dots are formed at positions on the print medium corresponding to the target pixel 216. When S26 ends, the process proceeds to S30.

  On the other hand, in the case of NO in S24, the determination unit 44 determines not to form a dot of a color corresponding to the corrected value PV ′ to be determined on the print medium. Next, the determination unit 44 stores the value of the new pixel at the same position as the target pixel in the work area 22 (S28). The value stored here is the dot output value “0” of the target color corresponding to the corrected value PV ′. For example, when the corrected value PV ′ of the target pixel 216 is K ′ (i, j), in S28, the determination unit 44 sets “K = 0 as the value of the new pixel at the same position as the target pixel. Is stored in the work area 22. When binary data including such information is supplied to the printer 50, black ink droplets are not ejected toward the position on the print medium corresponding to the target pixel 216. That is, no black dot is formed at a position on the print medium corresponding to the target pixel 216. When S28 ends, S30 to S33 are skipped and the process proceeds to S34.

  For example, when the C value is specified as PV in S20, “C = 1” is stored as a new pixel value at the same position as the target pixel in S26, and in S28, the same position as the target pixel is stored. “C = 0” is stored as the value of the new pixel. In the former case, cyan dots are formed at positions on the print medium corresponding to the target pixel, and in the latter case, cyan dots are not formed at positions on the print medium corresponding to the target pixel. When the M value or the Y value is specified in S20, the process is executed in the same manner as when the K value or the C value is specified in S20.

  In S30, the halftone processing unit 40 forms a nozzle (for example, “target nozzle” in the following) that forms a dot (for example, K) corresponding to PV ′ at a position on the print medium corresponding to the target pixel (for example, the pixel 216). Nozzle number (hereinafter referred to as “target nozzle number”). For example, when the color corresponding to PV ′ is K, the nozzle for K is specified as the target nozzle. Hereinafter, when a K nozzle is to be specified as the target nozzle, it is referred to as a “target K nozzle”. Next, a method for specifying the attention K nozzle number will be described in detail.

  First, when the first print mode corresponding to the first print resolution is selected by the user (that is, when the CMYK image data 210 of the first print resolution is generated in S16), the halftone processing unit 40 is used. The processing executed by will be described. As described above, the first print mode corresponding to the first print resolution is executed as shown in FIG. That is, in the first main scan, the K nozzles Nk1 to Nkn form rasters corresponding to the 1st to nth rows of the CMYK image data 210 of the first print resolution. Further, the transport distance (the first distance) in the first printing mode is a distance corresponding to n nozzle pitches. Based on these contents, it is possible to identify the noticeable K nozzle that forms a raster corresponding to the Lth row of the CMYK image data 210 of the first print resolution. In the printer driver 24 (see FIG. 1), a first K nozzle number table for specifying a noticeable K nozzle number from the row number of each pixel of the CMYK image data 210 of the first print resolution is registered in advance. Has been. When the first print resolution is selected by the user, the halftone processing unit 40 is based on the row number of the pixel of interest in the CMYK image data 210 and the first K nozzle number table. Thus, the notice K nozzle number is specified.

  Subsequently, when the second print mode corresponding to the second print resolution is selected by the user (that is, when the CMYK image data 210 of the second print resolution is generated in S16), the halftone processing unit The processing executed by 40 will be described. As described above, the second print mode corresponding to the second print resolution is executed as shown in FIG. 7, that is, for example, when n is an odd number, in the first main scan, The K nozzles Nkm to Nkn form rasters corresponding to the odd-numbered rows of the 1st to n-th rows of the CMYK image data 210 of the first print resolution. Furthermore, the transport distance (the second distance) in the second printing mode is, for example, a distance corresponding to n / 2 nozzle pitches when n is an odd number. Based on these contents, it is possible to identify the target K nozzle that forms a raster corresponding to the Lth row of the CMYK image data 210 of the second print resolution. In the printer driver 24 (see FIG. 1), a second K nozzle number table for specifying the target K nozzle number from each row number of the CMYK image data 210 corresponding to the second print resolution is registered in advance. ing. The control unit 30 specifies the target K nozzle number based on the row number of the target pixel in the CMYK image data 210 and the second K nozzle number table.

  In the printer driver 24, first and second nozzle number tables similar to the first and second K nozzle number tables are registered in advance for each of the three chromatic colors CMY. When the color corresponding to the PV specified in S20 is any one of the three chromatic colors CMY, the halftone processing unit 40 specifies the target nozzle number as in the case of K described above. For example, when the color corresponding to PV specified in S20 is C, the halftone processing unit 40 specifies the target C nozzle number using the first or second C nozzle number table. .

  When S30 ends, the halftone processing unit 40 determines whether or not the first print resolution has been selected by the user (S31). That is, the halftone processing unit 40 determines whether or not the current CMYK image data 210 to be subjected to the halftone process has the first print resolution. If YES in S31, the process proceeds to S32. On the other hand, if the CMYK image data 210 has the second print resolution, NO is determined in S31. In this case, S32 is skipped and the process proceeds to S33. In S <b> 32, the detection result acquisition unit 47 (see FIG. 1) transmits a specific command for acquiring the detection result of the current temperature of the print head 80 to the printer 50. The temperature detection unit 72 of the printer 50 detects the temperature of the print head 80 in accordance with the specific command and transmits the detection result to the PC 10. As a result, the detection result acquisition unit 47 acquires the detection result detected by the temperature detection unit 72. The detection result acquisition unit 47 stores the detection result in the work area 22.

  In S33, the correction data calculation unit 38 calculates correction data. The process of S33 changes according to the determination result of S31.

  First, the process of S33 when YES is determined in S31 (when S32 is executed) will be described. The data acquisition unit 36 (see FIG. 1) is based on the detection result acquired in S32 from the characteristic data table 60 stored in the work area 22 in S12 and the target nozzle number specified in S30. Acquire type or two types of temperature characteristic data. For example, when the detection result is 10 ° C., 25 ° C., or 40 ° C., the data acquisition unit 36 selects the detection result (temperature) from among the three types of temperature characteristic data corresponding to the nozzle number of interest. One type of corresponding temperature characteristic data is acquired. When only one type of temperature characteristic data is acquired, the one type of temperature characteristic data is referred to as “attention temperature characteristic data”. On the other hand, when the detection result is not 10 ° C., 25 ° C., or 40 ° C., the data acquisition unit 36 detects the above-described detection among the three types of temperature characteristic data corresponding to the target nozzle number. Two types of temperature characteristic data corresponding to temperatures close to the result are acquired. For example, when the detection result is less than 10 ° C., the data acquisition unit 36 includes 10 ° C. temperature characteristic data corresponding to the target nozzle number, 25 ° C. temperature characteristic data corresponding to the target nozzle number, To get. For example, when the detection result is a temperature between 25 ° C. and 40 ° C., the data acquisition unit 36 corresponds to the temperature characteristic data of 25 ° C. corresponding to the target nozzle number and the target nozzle number. Temperature characteristic data of 40 ° C. is acquired.

  Then, the correction data calculation unit 38 (see FIG. 1) calculates attention correction data. Specifically, when only one type of temperature characteristic data (that is, attention temperature characteristic data) is acquired by the data acquisition unit 36, the correction data calculation unit 38 adds 255 to the attention temperature characteristic data. To calculate attention correction data. On the other hand, when two types of temperature characteristic data are acquired by the data acquisition unit 36, the correction data calculation unit 38 assumes that the temperature characteristic data changes linearly with respect to the temperature of the print head 80. Using the two types of temperature characteristic data and the detection result, new temperature characteristic data corresponding to the detection result is calculated. When the temperature characteristic data Tt1 of t1 (° C.) and the temperature characteristic data Tt2 of t2 (° C.) are acquired and the detection result is t (° C.), the correction data calculation unit 38 calculates Tt2 + {( New temperature characteristic data is calculated by calculating Tt1-Tt2) / (t2-t1)} * (t2-t). When two types of temperature characteristic data are acquired, the new temperature characteristic data calculated by the correction data calculation unit 38 is referred to as “attention temperature characteristic data”. For example, when the target nozzle number is the nozzle number Nk1 and the detection result is 20 ° C., the data acquisition unit 36 acquires characteristic data “6” and “4” of 10 ° C. and 25 ° C. In this case, the correction data calculation unit 38 calculates the attention temperature characteristic data by calculating 4 + {(6-4) / (25-10)} × (25-20). Subsequently, the correction data calculation unit 38 calculates first attention correction data by adding 255 to the calculated attention temperature characteristic data.

  Subsequently, the process of S33 when it is determined NO in S31 (when S32 is not executed) will be described. From the characteristic data table 60 stored in the work area 22, the data acquisition unit 36 selects one type of temperature characteristic corresponding to 25 ° C. among the three types of temperature characteristic data corresponding to the target nozzle number identified in S 30. Get data only. One type of temperature characteristic data acquired here is also referred to as “attention temperature characteristic data”. In the process of S33 when NO is determined in S31, the correction data calculation unit 38 adds 255 to the temperature characteristic data corresponding to the target nozzle number of 25 ° C. (that is, the target temperature specifying data). The data for attention correction 2 is calculated. In another embodiment, the data acquisition unit 36 may acquire only one type of temperature characteristic data corresponding to 10 ° C. or 40 ° C. instead of the temperature characteristic data corresponding to 25 ° C.

  When S33 ends, the process proceeds to S34. Further, when S28 is executed, S30 to S33 are skipped and the process proceeds to S34. In S34, the error value calculation unit 46 (see FIG. 1) calculates an error value. The process of S34 changes according to the determination result of S24.

  First, the process of S34 when YES is determined in S24 (when S26 is executed) will be described. The error value calculation unit 46 subtracts the first or second attention correction data (hereinafter, simply referred to as “attention correction data”) obtained in S33 from the corrected value PV ′ obtained in S22. As a result, an error value ΔE is calculated. Equations for calculating the error value in this way are shown in the pixel 216 of FIG. That is, when the target pixel is the pixel 216 in FIG. 12 and PV ′ (i, j) obtained in S22 is larger than the threshold Th (in the case of YES in S24), the error value calculation unit 46 calculates PV ′ ( The error value ΔE (i, j) corresponding to the pixel 216 is calculated by subtracting the attention correction data from i, j). For example, when the color corresponding to PV specified in S20 is K, an error value corresponding to K of the pixel 216 is calculated. Similarly, when the color corresponding to PV specified in S20 is another color, an error value corresponding to the other color of the pixels 216 is calculated.

  Next, the process of S34 when NO is determined in S24 (when S28 is executed) will be described. In the case of NO in S24, the error value calculation unit 46 specifies the corrected value PV ′ obtained in S22 as an error value. An equation for calculating the error value in this way is shown in the pixel 217 of FIG. That is, when the pixel of interest is the pixel 217 in FIG. 12 and PV ′ (i + 1, j) obtained in S22 is smaller than the threshold Th (in the case of NO in S24), the error value calculation unit 46 displays the error value calculation unit 46 in FIG. An error value ΔE (i + 1, j) corresponding to the pixel 217 is specified using an expression in the pixel 217. That is, the error value calculation unit 46 calculates the error value using the corrected pixel value PV ′ without using the attention correction data.

  When S34 ends, the error value calculation unit 46 stores the error value (eg, ΔE (i, j)) specified in S34 in the work area 22 as the error value corresponding to the target pixel (S36). The error value stored here is used in the process of S22 to be executed later. For example, when the error value ΔE (i, j) corresponding to K of the pixel 216 is stored in S36, the error value ΔE (i, j) is K ′ corresponding to the K value of the pixel 217 in S22. Used when (i, j) is calculated.

  In S <b> 34 when the dot output value = 1, the error value ΔE is calculated by using the target temperature characteristic data corresponding to the target nozzle number, using the equation: ΔE = PV′−target correction data (255 + target temperature characteristic data). To do. Here, the characteristic data (hereinafter referred to as “minimum characteristic data”) corresponding to the nozzle having the smallest discharge amount is “0”. This means that the density of dots formed by the nozzle with the smallest discharge amount is assumed to be “255”. That is, the use of “255+ attention temperature characteristic data” as attention correction data means that the density of dots formed by the attention nozzle is assumed to be “255+ attention temperature characteristic data”. In S34, the difference between the target pixel value PV 'to be actually expressed and the assumed dot density "255+ attention temperature characteristic data" is calculated as the error value ΔE. This difference is diffused to neighboring pixels in the process of S22. Similarly, in S <b> 34 when the dot output value = 0, the error value ΔE is calculated by the equation ΔE = PV ′. That is, the difference between the value PV ′ of the target pixel to be actually expressed and the density “0” when no dot is formed is calculated as the error value ΔE. This difference is diffused to neighboring pixels in the process of S22.

  In S38, the halftone processing unit 40 determines whether or not the processing of S20 to S36 has been executed for all four CMYK pixel values (C value, M value, Y value, K value) constituting the target pixel. Judging. In the case of NO in S38, the halftone processing unit 40 returns to S20 and specifies a value for which the processing of S20 to S36 is not executed from the four values of CMYK constituting the target pixel. In the case of YES in S38, the halftone processing unit 40 determines whether or not the processing of S18 to S36 has been completed for all pixels constituting the CMYK image data 210 (S40). In the case of NO in S40, the halftone processing unit 40 returns to S18, and specifies the pixel next to the current pixel of interest (basically the pixel on the right) as a new pixel of interest. If YES in S40, the binary data generation process ends.

  As is clear from the above description, in the binary data generation process, C = 0 or 1, M = 0 or 1, Y = 0 or 1, from one pixel constituting the CMYK image data 210, A new pixel composed of K = 0 or 1 is generated. Accordingly, the number of pixels of the binary data is equal to the number of pixels of the CMYK image data 210. The supply unit 48 (see FIG. 1) transmits binary data and mode information indicating which of the first print mode and the second print mode is selected to the printer 50. As a result, the print execution unit 70 of the printer 50 executes print processing according to the binary data. That is, the print execution unit 70 corresponds to the K nozzle that forms the dot so that the black dot is formed at the position on the print medium corresponding to the pixel indicating K = 1 included in the binary data. Drive signals are supplied to the individual electrodes. Similarly, the print execution unit 70 supplies a drive signal so that dots of other colors are formed according to the binary data. As a result, an image represented by the RGB image data acquired in S10 of FIG. 8 (that is, an image represented by the converted RGB image data 200 obtained in S14, an image represented by the CMYK image data 210 obtained in S16, two An image represented by the value data) is formed on the print medium.

  This example has been described in detail. In this embodiment, when the user selects a relatively low first print resolution (that is, when the print execution unit 70 operates in the first print mode), the image processing unit 32 causes the print head 80 to The first attention correction data is calculated using the temperature characteristic data corresponding to the temperature (S33 in FIG. 8). As a result, the image processing unit 32 performs compensation processing for compensating for variations in the ejection amount, using the attention correction data that takes into account changes in the ejection amount of the ink droplets due to the temperature change of the print head 80. can do. As a result, binary data is generated in consideration of the change in the ink droplet ejection amount due to the temperature change of the print head 80. For this reason, the print execution unit 70 of the printer 50 has a higher image quality than when printing using binary data in which the change in the ink droplet ejection amount due to the temperature change of the print head 80 is not considered. Images can be printed on a print medium.

  On the other hand, when a relatively high second print resolution is selected by the user (that is, when the print execution unit 70 operates in the second print mode), the image processing unit 32 corresponds to the temperature of the print head 80. The attention correction data is calculated using the temperature characteristic data of the specific temperature (25 ° C.) without using the temperature characteristic data to be performed (S33 in FIG. 8). That is, a compensation process in which the temperature of the print head 80 is not taken into consideration is executed. In an image printed at a second printing resolution higher than the first printing resolution, the change in the ink droplet ejection amount due to the temperature change of the print head 80 is not noticeable. For this reason, when printing is performed at the second print resolution, an image obtained by executing compensation processing in consideration of the temperature of the print head 80 and compensation processing in which the temperature of the print head 80 is not taken into consideration. It is difficult to recognize a difference in image quality from an image obtained by executing the above. Therefore, in the present embodiment, when the second print resolution is selected, the image processing unit 32 performs a compensation process in which the temperature of the print head 80 is not taken into consideration. In this case, S32 in FIG. 8 is skipped, and new temperature characteristic data corresponding to the temperature of the print head 80 is not calculated in S33. For this reason, the processing load of the image processing unit 32 is reduced compared to the processing executed when the first print resolution is selected. As a result, the image processing unit 32 can generate binary data at high speed. In particular, when the print execution unit 70 operates in the second print mode, the number of times of main scanning is larger than when the print execution unit 70 operates in the first print mode. It takes. In this embodiment, when the print execution unit 70 operates in the second print mode, binary data is generated at a high speed, so that it is possible to suppress an increase in the time until printing is completed. .

  The control unit 30 of the PC 10 is an example of a “control device”. The characteristic data table 60 is an example of a “table”. Three types of temperature characteristic data are examples of “characteristic data”, for example, temperature characteristic data at 10 ° C. is “first type data”, and for example, temperature characteristic data at 25 ° C. is “second type data”. It is an example. The converted RGB image data 200, the CMYK image data 210, and the binary data generated in FIG. 8 are examples of “specific image data”, “target image data”, and “processed image data”, respectively. Further, the color conversion process and the halftone process are examples of “image processing”, and the error value calculation process executed when dot output = 1 in S34 of FIG. 8 is an example of “specific process”. Further, the first attention correction data calculated in S33 of FIG. 8 is an example of “correction data”, and the second attention correction data calculated in S33 of FIG. 8 is “other correction data”. Is an example.

(Second embodiment)
In the present embodiment, the contents of the binary data generation process executed by the control unit 30 of the PC 10 are different from those in the first embodiment. The contents of the binary data generation process of this embodiment will be described with reference to FIG. S10 to S16 are the same as in the first embodiment. When S16 ends, the color conversion processing unit 34 performs a correction process for generating corrected image data 250 (see FIG. 14) from the CMYK image data 210 (see FIG. 10). The correction process includes the processes of S50 to S62.

  The color conversion processing unit 34 identifies one pixel (hereinafter referred to as “target pixel”) from the CMYK image data 210 (S50). Hereinafter, the description will be continued by taking the case where the pixel 216 is the target pixel as an example. Next, the color conversion processing unit 34 specifies one value PV (i, j) from the four CMYK values that form the target pixel 216. Next, the color conversion processing unit 34 executes the process of S54 for specifying the nozzle number of interest using the same method as in S30 of FIG. When S54 ends, the process proceeds to S55. S55 and S56 are the same as S31 and S32 of FIG.

  In S57, the correction data calculation unit 38 specifies the temperature characteristic data of interest as in the process of S33 in FIG. The correction data calculation unit 38 calculates the target correction data CD (i, j) by calculating (255 + minimum temperature characteristic data) / (255 + target temperature characteristic data). In the present embodiment, in each of CMYK, the attention correction data for each pixel of interest in the j-th row has the same value. The “minimum temperature characteristic data” is temperature characteristic data indicating the minimum discharge amount among 3n temperature characteristic data corresponding to the n nozzles of the color corresponding to the PV specified in S52. As described above, in this embodiment, the “minimum temperature characteristic data” is zero. When S57 ends, the process proceeds to S58. In S <b> 58, the color conversion processing unit 34 calculates the corrected value PV ″ (i, j) by multiplying PV (i, j) by the target correction data CD (i, j). S60 and S62 are the same as S38 and S40 of FIG.

  The color conversion processing unit 34 calculates a corrected value PV ″ (i, j) for each of the four values CMYK constituting the target pixel 216. As a result, based on the target pixel 216, corrected pixels having four corrected values corresponding to the four colors of CMYK are generated. Similarly, the color conversion processing unit 34 generates corrected pixels for each pixel other than the pixel 216. Thereby, the corrected image data 250 shown in FIG. 14 is obtained. As described above, the color conversion processing unit 34 generates the corrected image data 250 from the CMYK image data 210 by executing the above correction processing in the CMYK color space.

  The halftone processing unit 40 performs halftone processing on the corrected image data 250 (S64). The halftone process of this embodiment is different from the halftone process (S18 to S40) of FIG. 8 in the following points. In S18, the target pixel in the corrected image data 250 is specified, and in S20, one value PV ″ (the corrected value) is specified from among the four values constituting the target pixel. The In S22, PV ′ is calculated by adding an error value (ie, Σs · ΔE) to PV ″ specified in S20. The processing of S30 to 33 shown in FIG. 8 is not executed. Further, in S34, when dot output = 1, the error value ΔE is calculated by subtracting 255 from PV ′. Other processes are the same as those in the first embodiment.

  The second embodiment has been described in detail. In the second embodiment, the same effects as in the first embodiment can be obtained. Note that the converted RGB image data 200 generated in S14 of FIG. 13 is an example of “specific image data” and “target image data”. The corrected image data 250 is an example of “color converted image data”. Further, the color conversion process, the correction process, and the halftone process are examples of “image processing”, and the color conversion process and the correction process are examples of “specific processing”. The first attention correction data calculated in S57 of FIG. 13 is an example of “correction data”, and the second attention correction data calculated in S57 is an example of “other correction data”. .

(Third embodiment)
In this embodiment, the print execution unit 70 of the printer 50 can execute the third print mode in addition to the first and second print modes. Hereinafter, the printing executed in the third printing mode may be referred to as “singling”. Note that single ring can also be referred to as an “overlap method”.

  With reference to FIG. 15, the monochrome printing single ring of the present embodiment will be described. In the case of color printing, in addition to the K nozzle group 84k, other color nozzle groups 84c and the like are also used to perform shingling as in the case of monochrome printing. In both the first printing mode and the second printing mode of the first embodiment, one K nozzle forms one raster by one main scan of the print head 80. On the other hand, in the single ring, two K nozzles form one raster by two main scans of the print head 80. For example, as shown in FIG. 15, in the first main scan of the print head 80, the K nozzle Nkm + 3 forms a dot group Dkm + 3. Next, in the second main scan of the print head 80, the K nozzle Nk4 forms a dot group Dk4. The dot group Dkm + 3 and the dot group Dk4 constitute one raster R4. As is apparent from the above description, in the first main scan, the dot group Dkm + 3 is formed according to the first pixel group corresponding to half of the plurality of pixels constituting a specific row of binary data. In the second main scanning, the dot group Dk4 is formed according to the remaining second pixel group constituting the specific row. The first pixel group and the second pixel group have a relationship of being alternately located in the specific row of the binary data. That is, each of the first pixel groups is, for example, a pixel belonging to an even number column, and each of the second pixel group is, for example, a pixel belonging to an odd number column.

  For example, when n is an odd number, one K nozzle Nkn arranged at the most upstream side in the sub-scanning direction is not used in shingling. In the first main scanning, each of (n−1) / 2 K nozzles Nkm to Nkn−1 forms a first dot group (see dot Dkm + 3 in FIG. 15). Next, the print execution unit 70 carries the print medium 150. In the single ring, the third distance is adopted as the transport distance here. The third distance is a distance corresponding to (n−1) / 2 nozzle pitch. When this conveyance is performed, as shown in FIG. 15, each of the (n−1) / 2 K nozzles Nk1 to Nkm−1 arranged on the downstream side is Arranged at the same position as the first dot group. For example, the K nozzle Nk4 is arranged at the same position as the dot Dkm + 3. In this state, the print execution unit 70 executes the second main scan of the print head 80. Thereby, each of the (n-1) / 2 K nozzles Nk1 to Nkm-1 arranged on the downstream side forms the second dot group (see the dot Dk4 in FIG. 15). The first dot group and the second dot group constitute (n−1) / 2 rasters R1 and the like. In the second main scanning, the (n-1) / 2 K nozzles Nkm to Nkn-1 arranged on the upstream side also form a dot group. The print execution unit 70 repeatedly executes a combination of conveyance of the third distance of the print medium 150 and main scanning of the print head 80. As a result, the image represented by the binary data is printed on the print medium.

  As is clear from the above description, the printing resolution in the sub-scanning direction of the single ring is the same as the first printing resolution in the first printing mode. However, the printing result of the shingling has a higher image quality than the printing result of the first printing mode. For example, in the first printing mode, since one nozzle forms one raster, the difference in the ejection amount of each nozzle appears as a density difference between the rasters. On the other hand, in the single ring, since two nozzles form one raster, the difference in the discharge amount of each nozzle hardly appears as the density difference between the rasters.

  In this embodiment, when the user performs an operation for printing desired image data on the operation unit 12 of the PC 10, one print mode is selected from the first, second, and third print modes. Can be selected. As described above, in the first embodiment, the first and second nozzle number tables are registered in the printer driver 24. In the present embodiment, in addition to these tables, four third nozzle number tables corresponding to four colors of CMYK are registered in the printer driver 24. The third nozzle number table is a table for specifying the target nozzle number from the row number and column number of the target pixel in the case of shingling. For example, in the third K nozzle number table, for example, when any pixel group in the CMYK image data 210 corresponding to the dot group Dkm + 3 in FIG. 15 is the target pixel, the target K nozzle number Nkm + 3 is set. Information that can be identified is registered. In S30 of FIG. 8, for example, the halftone processing unit 40 identifies the target K nozzle number using the third K nozzle number table. Other processing is the same as the binary data generation processing (processing in the case of NO in S31 of FIG. 8) executed when the second printing mode is selected. In the present embodiment, in each of CMYK, the attention correction data for the target pixel belonging to the same row differs depending on the target nozzle. For example, when any of the pixel groups in the CMYK image data 210 corresponding to the dot group Dkm + 3 in FIG. 15 is the target pixel, the target temperature correction data using the target temperature characteristic data corresponding to the target K nozzle number Nkm + 3 is used. Data is calculated. On the other hand, for example, when any of the pixel groups in the CMYK image data 210 corresponding to the dot group Dk4 in FIG. 15 is the target pixel, the target temperature characteristic data corresponding to the target K nozzle number Nk4 is used. Attention correction data is calculated.

  As described above, the printing result of the single ring has a higher image quality than the printing result of the first printing mode. Accordingly, in the image obtained in the case of shingling, the change in the ejection amount of the ink droplets due to the temperature change of the print head 80 is hardly noticeable. For this reason, in this embodiment, when the third printing mode is selected, the image processing unit 32 performs compensation processing in which the temperature of the print head 80 is not taken into consideration (processing in the case of NO in S31 of FIG. 8). ) To reduce the processing load. As a result, the image processing unit 32 can generate binary data at high speed. When the print execution unit 70 operates in the third print mode, it takes time to print because the number of times of main scanning is larger than when the print execution unit 70 operates in the first print mode. . In this embodiment, when the print execution unit 70 operates in the third print mode, binary data is generated at a high speed, so that it is possible to suppress an increase in the time until printing is completed. . As is apparent from the above description, the third print mode of this embodiment is an example of the “second print mode” when the first print resolution and the second print resolution are the same.

(Fourth embodiment)
In each of the above embodiments, the characteristic data table 60 (see FIG. 3) is stored in the storage unit 56 of the printer 50. In the present embodiment, the storage unit 56 of the printer 50 stores a specific characteristic data table different from the characteristic data table 60 and a correction coefficient table 400 shown in FIG. Of the three types of temperature characteristic data (10 ° C., 25 ° C., 40 ° C.) registered in the characteristic data table 60 of FIG. 3, only the temperature characteristic data of 25 ° C. is registered in the specific characteristic data table. Has been.

  In the correction coefficient table 400, correction coefficients of temperature characteristic data are registered for each of the four colors CMYK. For example, for K, a K correction coefficient (1.35) at 10 ° C. and a K correction coefficient (0.75) at 40 ° C. are registered. The vendor of the printer 50 specifies these two K correction coefficients as follows. First, the vendor generates the characteristic data table 60 of FIG. 3 using the method of the first embodiment. Next, the vendor calculates the first average value of the n 10 ° C. temperature characteristic data and the n 25 ° C. temperature characteristic data based on the 3n temperature characteristic data corresponding to the K nozzle group 84k. A second average value and a third average value of n pieces of temperature characteristic data of 40 ° C. are calculated. The vendor calculates the K correction coefficient (1.35) at 10 ° C. by dividing the first average value by the second average value. Further, the vendor calculates the K correction coefficient (0.75) at 40 ° C. by dividing the third average value by the second average value. Thereby, two correction factors for K corresponding to 10 ° C. and 40 ° C. are specified. The vendor specifies two correction factors corresponding to 10 ° C. and 40 ° C. for each of CMY, using the same method as in the case of the change rate for K.

  In this embodiment, the control unit 30 of the PC 10 acquires not only the specific characteristic data table but also the correction coefficient table 400 from the printer 50 in S12 of FIG. In addition, when the first attention correction data is calculated in S33 of FIG. 8 (that is, when YES is determined in S31 of FIG. 8), the data acquisition unit 36 determines from the specific characteristic data table described above. Temperature characteristic data at 25 ° C. corresponding to the target nozzle number is acquired. Further, when the detection result acquired in S32 is higher than 25 ° C., the data acquisition unit 36 acquires a correction coefficient of 40 ° C. for the color corresponding to the PV specified in S20 from the correction coefficient table 400. In addition, when the detection result acquired in S <b> 32 is lower than 25 ° C., the data acquisition unit 36 acquires a correction coefficient of 10 ° C. for the color corresponding to the PV specified in S <b> 20 from the correction coefficient table 400. The data acquisition unit 36 sets the correction coefficient to 1 without acquiring the correction coefficient when the detection result acquired in S32 is 25 ° C.

  Next, when the correction coefficient is acquired, the correction data calculation unit 38 uses the correction coefficient, the acquired temperature characteristic data of 25 ° C., and the acquired detection result to detect the detection result. New temperature characteristic data corresponding to (i.e., attention temperature characteristic data) is calculated. The correction data calculation unit 38 calculates the target temperature characteristic data on the assumption that the temperature characteristic data changes linearly with respect to the temperature of the print head 80. When the temperature characteristic data Tt1 of 25 ° C. and the correction coefficient h2 of t2 (° C.) are acquired and the detection result is t (° C.), the correction data calculation unit 38 calculates Tt1 × h2. Thus, temperature characteristic data Tt2 at t2 ° C. is calculated. Next, as in the first embodiment, the temperature characteristic data of interest is calculated by calculating Tt2 + (Tt1−Tt2) × ((t2−t) / (t2−25 (° C.)). When the detection result acquired in S32 is 25 ° C., the acquired temperature characteristic data of 25 ° C. is the attention temperature characteristic data. For example, when the nozzle number of interest is the nozzle number Nk1 and the detection result acquired in S32 is 20 ° C., the data acquisition unit 36 associates the nozzle number Nk1 with the characteristic data “ 4 ”and“ 1.35 ”registered in the correction coefficient table 400 in association with 10 ° C. are acquired. In this case, the correction data calculation unit 38 calculates (4 × 1.35), and then (4 × 1.35) + (4−4 × 1.35) × {(10−20) / ( 10-25)} to calculate the temperature characteristic data of interest. Next, the correction data calculation unit 38 calculates the first attention correction data by adding 255 to the attention temperature characteristic data. When the second attention correction data is calculated in S33 of FIG. 8 (that is, when NO is determined in S31 of FIG. 8), the data acquisition unit 36 associates with the noticeable nozzle number in the characteristic data table 300. Is acquired, and the correction coefficient registered in the correction coefficient table 400 is not acquired. The correction data calculation unit 38 calculates second attention correction data using the acquired characteristic data. Other processes are the same as those in the first embodiment. In this embodiment, the number of data to be registered in the tables 300 and 400 is smaller than that in the first embodiment. The correspondence between each element of the present embodiment and each element of the present invention will be described. The characteristic data table 300 and the correction coefficient table 400 are examples of “tables”. The temperature characteristic data of 25 ° C. and the correction coefficient are examples of “characteristic data”, the temperature characteristic data of 25 ° C. is an example of “first type data”, and the correction coefficient is an example of “correction value”. is there.

Modifications of the above embodiments are listed below.
(1) In the above-described embodiment, the control unit 30 of the PC 10 includes the image processing unit 32 and the supply unit 48. Instead, the printer 50 includes the image processing unit 32 and the supply unit 48. May be. In this case, the printer is an example of a “control device”.

(2) In the embodiment described above, the PC 10 acquires the characteristic data table 60 from the printer 50 after receiving a print instruction from the user. However, the PC 10 may acquire the characteristic data table 60 from the printer 50 at the timing when the printer driver 24 is installed in the PC 10 and hold the characteristic data table 60. Further, the PC 10 may acquire necessary characteristic data from the printer 50 each time the process of S33 or S34 in FIG.

(3) In the embodiment described above, the second print resolution corresponding to the second print mode is twice the first print resolution corresponding to the first print mode. However, the second print resolution may be three times or more the first print resolution. For example, when the second print resolution is three times the first print resolution, one adjacent line is formed by the second main scan between two adjacent rasters formed by the first main scan. A raster is formed, and one raster is formed by the third main scanning between the two adjacent rasters.

(4) In the above-described embodiment, the halftone processing unit 40 generates binary data indicating dot output = 1 and dot output = 0. However, the halftone processing unit 40 may generate ternary or higher data. For example, the halftone processing unit 40 has a value “3” corresponding to a large dot, a value “2” corresponding to a medium dot, a value “1” corresponding to a small dot, and “0” corresponding to no dot. Further, quaternary data indicating the above may be generated. In this case, the halftone processing unit 40 uses a threshold value Th1 (for example, 191) for distinguishing large dots and medium dots as a threshold value used in S24 of FIG. 8, and for distinguishing medium dots and large dots. You may utilize threshold value Th2 (for example, 127) and threshold value Th3 (for example, 63) for classifying a small dot and no dot. In this example, the halftone processing unit 40 may change the attention correction data calculated in S33 or S34 of FIG. 8 according to the dot size to be formed. For example, when medium dots are formed, the halftone processing unit 40 (255+ attention temperature characteristic data) × (density to be expressed by medium dots) / (density to be expressed by large dots (for example, 255). )) Is specified as the data for attention correction, and when small dots are formed, (255+ attention temperature characteristic data) × (density to be expressed by small dots) / (density to be expressed by large dots ( For example, 255)) may be specified as the attention correction data.

(5) In the above-described embodiment, the error value calculated in S34 is stored in the work area 22 as the error value corresponding to the target pixel in S36 of FIG. In S <b> 22 of FIG. 8, the correction unit 42 calculates PV ′ by collecting the error values (error values corresponding to pixels near the target pixel) stored in S <b> 36. Instead of this configuration, the correction unit 42 may assign the error value calculated in S34 to each unprocessed pixel near the target pixel in S36. For example, when the error value ΔEk (i, j) corresponding to K of the pixel 216 in FIG. ) And a value obtained by multiplying the error value ΔEk and the coefficient s, the new K value of the pixel 217 may be calculated. When this configuration is adopted, the PV specified in S20 of FIG. 8 is equal to PV ′, and the process of S22 of FIG. 8 is not executed.

(6) In the second embodiment described above, the halftone processing unit 40 performs the halftone process using the error diffusion method. Instead, the halftone process is performed using the dither method. May be executed.

(7) In the third embodiment, the shingling forms one raster by two nozzles by two main scans. Instead, one nozzle by two main scans. May form one raster. One raster may be formed by three or more nozzles by three or more main scans.

(8) In the characteristic data table 60 of FIG. 3, the temperature characteristic data corresponding to the nozzle with the minimum discharge amount is set to zero for each color of CMYK. However, for example, temperature characteristic data corresponding to a nozzle having a predetermined reference discharge amount may be set to zero. In this case, in the characteristic data table 60 of FIG. 3, temperature characteristic data having a negative value may exist.

(9) In the first embodiment, the numerical value “255” is adopted to calculate the attention correction data (255+ attention temperature characteristic data) in S33 of FIG. This means that “255 (the maximum value that can be taken by the pixels in the CMYK image data 210)” is adopted as the density value of the dots formed by the nozzle with the smallest discharge amount. Instead of this configuration, a numerical value other than “255” may be used as a numerical value for calculating the attention correction data. Also in the second embodiment, (255 + minimum temperature characteristic data) / (255+ attention temperature characteristic data) is employed when calculating the attention correction data. This also means that “255” is adopted as the density value of the dots formed by the nozzle with the smallest discharge amount. Instead of this configuration, a numerical value other than “255” may be used as a numerical value for calculating the attention correction data.

(10) In the embodiment described above, the correction data calculation unit 38 calculates correction data using the temperature characteristic data of the nozzle of interest in S33 of FIG. However, the correction data calculation unit 38 may calculate the correction data using the temperature characteristic data of the nozzle of interest and the temperature characteristic data of the specific nozzle. The specific nozzle preferably includes a nozzle that forms a raster adjacent to a raster including dots formed by the nozzle of interest (hereinafter referred to as “target raster”). For example, in FIG. 5 (first printing mode), when the target K nozzle is the nozzle Nk4 (when the target raster is R4), the specific nozzles form the rasters R2, R3, R5 to R7. The nozzles Nk2, Nk3, Nk5 to Nk7 may be used. In this case, in S30 of FIG. 8, the halftone processing unit 40 may acquire the nozzle number of interest and the nozzle number of the specific nozzle (hereinafter referred to as “specific nozzle number”). In S33 of FIG. 8, when calculating the first attention correction data, the data acquisition unit 36 determines from the characteristic data table 60 not only one or two types of temperature characteristic data corresponding to the target nozzle number. For each of the plurality of specific nozzle numbers, one type or two types of temperature characteristic data corresponding to the specific nozzle number may be acquired. Next, the correction data calculation unit 38 may specify the target temperature characteristic data for each of the plurality of specific nozzles, similarly to the method of specifying the target temperature characteristic data in the above-described embodiment. Subsequently, the correction data calculation unit 38 adds 255 to the average value of the target temperature characteristic data corresponding to the target nozzle and the plurality of target temperature characteristic data corresponding to the plurality of specific nozzles. The attention correction data may be calculated. When calculating the second attention correction data in S33 of FIG. 8, the data acquisition unit 36 includes not only the temperature characteristic data of 25 ° C. corresponding to the attention nozzle number from the characteristic data table 60 but also a plurality of pieces of data. For each specific nozzle number, temperature characteristic data of 25 ° C. corresponding to the specific nozzle number may be acquired. Next, the correction data calculating unit 38 adds 255 to the average value of the temperature characteristic data corresponding to the target nozzle and the plurality of temperature characteristic data corresponding to the plurality of specific nozzles, thereby correcting the target. Data may be calculated.

(11) The technology disclosed in this specification can be used for a patterning apparatus for forming a pattern on a substrate in addition to a printer.

(12) In each of the above embodiments, the temperature detection unit 72 includes a temperature sensor directly attached to the print head 80, and the temperature sensor is preferably attached in the vicinity of the actuator unit, for example. However, the temperature detection unit 72 may include a temperature sensor mounted on a member (for example, a carriage) around the print head 80.

(13) In the first embodiment, the temperature characteristic data close to the detection result acquired in S32 of FIG. 8 may be used as the above noted temperature characteristic data without assuming that the temperature characteristic data changes linearly. For example, when the detection result is 12 ° C., in S33 of FIG. 8, the data acquisition unit 36 (see FIG. 1) determines that the detection result is 10 ° C. based on the detection result and the target nozzle number specified in S30. You may acquire temperature characteristic data (namely, attention temperature characteristic data).

(14) In the above embodiment, instead of assuming that the temperature characteristic data changes linearly, it may be assumed that the temperature characteristic data changes nonlinearly. In the above embodiment, the temperature characteristic data is a value corresponding to a specific temperature of the print head 80. However, the temperature characteristic data may be a function. For example, for each of 4n nozzles, the vendor uses a function of temperature and temperature characteristic data obtained by using the least square method from three types of temperature characteristic data corresponding to 10 ° C., 25 ° C., and 40 ° C. of the nozzle. May be specified. In this case, the nozzle number and the above function may be stored in the characteristic data table 60 in association with each other. That is, the characteristic data may include the nozzle number and the above function. In this case, the correction data calculation unit 38 may calculate the temperature characteristic data of interest using the function acquired by the data acquisition unit 36 and the detection result.

(15) In the fourth embodiment, the correction coefficient table 400 (see FIG. 16) is stored in the storage unit 56 of the printer 50. In the correction coefficient table 400, correction coefficients for calculating the temperature characteristic data of the temperature corresponding to the correction coefficient by multiplying the temperature characteristic data of 25 ° C. are registered. However, another table may be stored in the storage unit 56 of the printer 50. In another table, for example, correction amounts corresponding to 10 ° C. and 40 ° C. may be registered. The 10 ° C. correction amount is the difference between the 25 ° C. temperature characteristic data and the 10 ° C. temperature characteristic data, and the 40 ° C. correction amount is the difference between the 25 ° C. temperature characteristic data and the 40 ° C. temperature characteristic data. Also good. In this case, the temperature characteristic data of 25 ° C. and the correction amount are examples of “characteristic data”, and the correction amount is an example of “correction value”. Or the change rate corresponding to each of 10 degreeC and 40 degreeC may be registered into another table, for example. For example, the rate of change at 10 ° C. is a value obtained by dividing the change in temperature characteristic data at 10 ° C. and the change in temperature characteristic data at 25 ° C. by the change in temperature (ie, the temperature characteristic data is assumed to change linearly with respect to temperature. The slope of the straight line). In this case, the temperature characteristic data at 25 ° C. and the rate of change are examples of “characteristic data”, and the rate of change is an example of “correction value”.

(16) In the characteristic data table 60 of FIG. 3, the characteristic data corresponding to the nozzle having the smallest ejection amount may be set to 255. That is, the characteristic data may be a value obtained by adding 255 to the value shown in FIG. In this case, 255 may not be added to the temperature characteristic data of interest in S33 of FIG.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

2: network system, 12: operation unit, 14: display unit, 16: network interface, 20: storage unit, 22: work area, 24: printer driver, 30: control unit, 32: image processing unit, 34: color conversion Processing unit 36: Data acquisition unit 38: Correction data calculation unit 40: Halftone processing unit 42: Correction unit 44: Determination unit 46: Error value calculation unit 47: Detection result acquisition unit 48 Supply unit, 50: printer, 52: network interface, 54: display unit, 56: storage unit, 60: characteristic data table, 64: program, 70: print execution unit, 72: temperature detection unit, 80: print head, 84k , 84c, 84m, 84y: nozzle group, 200: converted RGB image data, 210: CMYK image data, 250: corrected image data, 3 0: correction data table

Claims (8)

A control device for causing a print execution unit including a print head formed with a plurality of nozzles for discharging droplets to execute printing,
An image processing unit that generates processed image data by performing image processing on specific image data;
A supply unit for supplying the processed image data to the print execution unit,
The image processing unit is arranged on a print medium corresponding to the target pixel with respect to the target pixel in target image data in order to compensate for variations in the discharge amount of droplets discharged from the plurality of nozzles. Using the correction data for the nozzle of interest that forms a dot at the position, execute a specific process,
The correction data is data obtained using attention characteristic data corresponding to the attention nozzle among a plurality of characteristic data corresponding to the plurality of nozzles and a detection result of the temperature of the print head. Yes,
The control device, wherein the characteristic data is data related to a discharge amount of a droplet discharged from a corresponding nozzle. The image processing unit
A detection result acquisition unit for acquiring the detection result of the temperature of the print head;
A data acquisition unit that acquires the target characteristic data corresponding to the target nozzle from a table in which the plurality of characteristic data are registered;
A correction data calculation unit that calculates the correction data for the target nozzle using the target characteristic data corresponding to the target nozzle and the detection result of the temperature of the print head;
The control device according to claim 1, comprising: Each of the plurality of characteristic data corresponding to the plurality of nozzles is:
When the print head is at the first temperature, the first type of data related to the discharge amount of the droplets discharged from the corresponding nozzle;
When the print head is at the second temperature, the second type of data relating to the ejection amount of the droplets ejected from the corresponding nozzle, and
The correction data calculation unit includes the first type of data included in the target characteristic data corresponding to the target nozzle, the second type of data included in the target characteristic data corresponding to the target nozzle, The control device according to claim 2, wherein the correction data for the nozzle of interest is calculated using the detection result of the temperature of the print head. Each of the plurality of characteristic data corresponding to the plurality of nozzles is:
When the print head is at the first temperature, the first type of data related to the discharge amount of the droplets discharged from the corresponding nozzle;
When the print head is at the second temperature, the correction value for generating the second type of data related to the ejection amount of the droplets ejected from the corresponding nozzle using the first type of data. And including
The correction data calculation unit uses the first type data included in the target characteristic data corresponding to the target nozzle, the correction value, and the detection result of the temperature of the print head. The control device according to claim 2, wherein the correction data for the nozzle of interest is calculated. The print execution unit
A first print mode in which the print head performs the first number of main scans to print an image represented by the specific image data on the print medium at a first print resolution;
The print head performs a second number of main scans greater than the first number of times to print the image represented by the specific image data on the print medium at a second print resolution. 2 print modes;
Can work with
The second print resolution is higher than the first print resolution or the same print resolution as the first print resolution;
The image processing unit
For the target nozzle obtained using the target characteristic data corresponding to the target nozzle and the temperature detection result of the print head when the print execution unit operates in the first print mode. Using the correction data, the specific process is executed,
When the print execution unit operates in the second print mode, the print execution unit for the target nozzle obtained using the target characteristic data corresponding to the target nozzle without using the temperature detection result of the print head. The control device according to claim 1, wherein the specific processing is executed using other correction data. The image processing unit
The target image data expressed in the second type color space is generated by performing color conversion processing on each pixel in the specific image data expressed in the first type color space. A color conversion processing unit;
A halftone processing unit that generates the processed image data by performing halftone processing on the target image data,
The halftone processing unit
A correction unit that generates a corrected value by correcting the value of the target pixel in the target image data using a plurality of error values corresponding to a plurality of neighboring pixels in the vicinity of the target pixel. When,
A determination unit that determines whether or not to form a dot at the position on the print medium corresponding to the target pixel based on the corrected value and a threshold corresponding to the target pixel;
An error value calculation unit that calculates an error value corresponding to the target pixel in accordance with the determination regarding whether or not to form a dot for the target pixel;
When it is determined that a dot is to be formed for the target pixel, the error value calculation unit calculates the error value corresponding to the target pixel using the corrected value and the correction data. The control apparatus according to claim 1, wherein the specific process to be calculated is executed. The target image data is the specific image data,
The image processing unit
Expressed in the second type color space by executing the specific processing including color conversion processing and correction processing for each pixel in the target image data expressed in the first type color space A color conversion processing unit that generates color-converted image data,
A halftone processing unit that generates the processed image data by performing a halftone process on the color-converted image data,
The color conversion processing unit
By executing the color conversion process on the target pixel in the target image data, a color-converted pixel expressed in the second type color space is generated,
6. The corrected pixel is generated by executing the correction process on the color-converted pixel in the second type color space using the correction data. 6. The control device according to any one of the above. A computer program,
A control device for causing a print execution unit including a print head formed with a plurality of nozzles for discharging droplets to execute printing has the following steps:
An image processing step for generating processed image data by performing image processing on specific image data; and
Supplying the processed image data to the print execution unit, and
In the image processing step, on the print medium corresponding to the target pixel with respect to the target pixel in the target image data in order to compensate for variations in the discharge amount of the droplets discharged from the plurality of nozzles. Using correction data for the nozzle of interest that forms a dot at a position, and performing a specific process,
The correction data is data obtained using attention characteristic data corresponding to the attention nozzle among a plurality of characteristic data corresponding to the plurality of nozzles and a detection result of the temperature of the print head. Yes,
The said characteristic data is a computer program which is data related to the discharge amount of the droplet discharged from a corresponding nozzle.

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