Liquid droplet ejection device

Abstract

To easily reduce the variations in the discharge characteristic of droplets between a plurality of nozzles.SOLUTION: A plurality of first pattern portions 72A-72I which are arrayed in the scan direction are recorded by discharging ink droplets from at least a nozzle 10a on the most upstream side in the conveyance direction of a nozzle array 9. A plurality of second pattern portions 82A-82I which are arrayed in the scan direction are recorded by discharging ink droplets from at least a nozzle 10b on the most downstream side in the conveyance direction of the nozzle array 9. The portions recorded by the nozzle 10a of the first pattern portions 72A-72I and the portions recorded by the nozzle 10b of the second pattern portions 82A-82I are arrayed adjacently in the conveyance direction. The first pattern portions 72F-72I have a density smaller than that of the first pattern portions 72A-72E and the density becomes smaller toward the right end. The second pattern portions 82A-82D have a density smaller than that of the second pattern portions 82E-82I and the density becomes smaller toward the left end.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a droplet ejection device that ejects droplets from a nozzle. [Background technology]

[0002] As an example of a droplet ejection device that ejects droplets from nozzles, Patent Document 1 describes an image recording device that performs recording by ejecting ink from nozzles. In the image recording device described in Patent Document 1, an inkjet head mounted on a carriage has multiple nozzles aligned in the transport direction. Then, while moving the carriage in the scanning direction, a recording pass in which ink is ejected from the multiple nozzles of the inkjet head to form dots on paper, and a transport operation in which the paper is transported in the transport direction are repeatedly performed to record on the paper. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-177556 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the image recording device described in Patent Document 1, the ink ejection amount may vary among the nozzles in the inkjet head due to manufacturing variations. In this case, when recording is performed by repeating the recording pass and the transport operation as described above, there is a risk of uneven density occurring in the recorded image along the transport direction. Also, even in an image recording device having a so-called line head in which multiple nozzles are arranged along the entire length of the recording paper in a direction perpendicular to the transport direction of the recording paper and are arranged in the transport direction of the recording paper, if there is unevenness in the ink ejection amount among the nozzles arranged in the transport direction, there is a risk of uneven density occurring as described above.

[0005] An object of the present invention is to provide a droplet ejection device that can easily correct variations in droplet ejection characteristics among a plurality of nozzles. [Means for solving the problem]

[0006] A droplet discharge device according to the present invention includes a droplet discharge head having a nozzle row made up of a plurality of nozzles arranged in a first direction, relative movement means for relatively moving the droplet discharge head and a discharge receiving medium in the first direction, and a control unit, and the control unit controls the droplet discharge head and the relative movement means to record an unevenness correction pattern on the discharge receiving medium for correcting variations in the amount of droplet discharged between the plurality of nozzles, and when recording the unevenness correction pattern, causes the droplet discharge head to discharge droplets from at least a first nozzle at one of the outermost ends of the nozzle row in the first direction, thereby recording a first pattern group which is part of the unevenness correction pattern and is made up of a plurality of first pattern portions lined up in a second direction intersecting with the first direction, and then causes the relative movement means to relatively move the droplet discharge head and the discharge receiving medium a predetermined distance in the first direction, and then causes the droplet discharge head to discharge droplets from at least a second nozzle at the other outermost end of the nozzle row in the first direction, thereby a second pattern group is recorded, the second pattern group being a part of the unevenness correction pattern, the second pattern group being arranged in the second direction, and the second pattern group being composed of a plurality of second pattern portions arranged in such a way that a portion recorded by the first nozzle of the plurality of first pattern portions in the first direction is adjacent to a portion recorded by the second nozzle, the first pattern group including a reference first pattern portion located between one outermost first pattern portion and the other outermost first pattern portion in the second direction, the second pattern group including a reference second pattern portion located between one outermost second pattern portion and the other outermost second pattern portion in the second direction and adjacent to the reference first pattern portion in the first direction, when the first pattern group is recorded, a density of the one outermost first pattern portion in the second direction is made lighter than a density of the reference first pattern portion, and when the second pattern group is recorded, a density of the other outermost second pattern portion in the second direction is made lighter than a density of the reference second pattern portion.

[0007] Further, a droplet discharge device of the present invention includes a droplet discharge head having a nozzle row composed of a plurality of nozzles arranged in a first direction, relative movement means for relatively moving the droplet discharge head and a discharge receiving medium in the first direction, and a control unit, wherein the control unit controls the droplet discharge head and the relative movement means to record an unevenness correction pattern on the discharge receiving medium for correcting variations in the amount of droplet discharged between the plurality of nozzles, and when recording the unevenness correction pattern, causes the droplet discharge head to discharge droplets from at least a first nozzle at one of the outermost ends of the nozzle row in the first direction, thereby recording a first pattern group which is part of the unevenness correction pattern and is composed of a plurality of first pattern portions lined up in a second direction intersecting with the first direction, and then causes the relative movement means to relatively move the droplet discharge head and the discharge receiving medium a predetermined distance in the first direction, and then causes the droplet discharge head to discharge droplets from at least a second nozzle at the other outermost end of the nozzle row in the first direction, thereby a second pattern group is recorded, the second pattern group being a part of the unevenness correction pattern, the second pattern group being aligned in the second direction, and the second pattern group being composed of a plurality of second pattern portions, each of which has a portion recorded by the first nozzle of the plurality of first pattern portions aligned in the first direction and a portion recorded by the second nozzle being adjacent to the portion recorded by the first nozzle of the plurality of first pattern portions, the first pattern group including a reference first pattern portion located between one of the outermost first pattern portions in the second direction and the other of the outermost first pattern portions, and the second pattern group including a reference second pattern portion located between one of the outermost second pattern portions in the second direction and the other of the outermost second pattern portions and adjacent to the reference first pattern portion in the first direction, and when the first pattern group is recorded, a density of the one of the outermost first pattern portions in the second direction is made darker than a density of the reference first pattern portion, and when the second pattern group is recorded, a density of the other of the outermost second pattern portions in the second direction is made darker than a density of the reference second pattern portion.

[0008] Further, a droplet discharge device of the present invention includes a droplet discharge head having a plurality of nozzles arranged in a first direction, relative movement means for relatively moving the droplet discharge head and a discharge receiving medium in the first direction, and a control unit, wherein the control unit controls the droplet discharge head and the relative movement means to cause an unevenness correction pattern for correcting unevenness in the amount of droplet discharged between the plurality of nozzles in the droplet discharge head to be recorded on the discharge receiving medium, and is configured to be able to receive a characteristic signal indicating whether the droplet discharge head has a first characteristic or a second characteristic different from the first characteristic as a characteristic relating to unevenness in the amount of droplet discharged between the plurality of nozzles, and when the unevenness correction pattern is recorded on the discharge receiving medium, the control unit is configured to receive a characteristic signal indicating whether the droplet discharge head has a first characteristic or a second characteristic different from the first characteristic, When the characteristic signal indicates that the droplet ejection head has the first characteristic, the droplet ejection head and the relative movement means are controlled to record, as the unevenness correction pattern, a first unevenness correction pattern on the recording medium, for correcting the variation in the droplet ejection amount between the multiple nozzles in the droplet ejection head having the first characteristic, and when the received characteristic signal indicates that the droplet ejection head has the second characteristic, the droplet ejection head and the relative movement means are controlled to record, as the unevenness correction pattern, a second unevenness correction pattern, different from the first unevenness correction pattern, on the recording medium, for correcting the variation in the droplet ejection amount between the multiple nozzles in the droplet ejection head having the second characteristic. Effect of the Invention

[0009] In the present invention, it is possible to reduce the variation in droplet ejection amount between nozzles based on the results of printing the unevenness correction pattern. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of a printer according to an embodiment of the present invention; [Diagram 2] 2 is a diagram showing the positional relationship between a carriage, a subtank, an inkjet head, a platen, and a transport roller as viewed from the direction of an arrow II in FIG. 1. [Diagram 3]FIG. 2 is a block diagram showing the electrical configuration of the printer. [Figure 4] FIG. 4A is a diagram illustrating an example of the characteristics of an inkjet head, and FIG. 4B is a diagram illustrating another example of the characteristics of an inkjet head. [Diagram 5] 11 is a flowchart showing a flow of processing performed at the time of initial startup. [Figure 6] FIG. 1A is a diagram for explaining the recording of a first pattern group, FIG. 1B is a diagram for explaining the recording of a second pattern group, and FIG. 1C is a diagram for explaining the recording of selection symbols. [Figure 7] (a) is a diagram for explaining the thinning rate of the mask data used to print each first pattern portion, (b) is a diagram for explaining the thinning rate of the mask data used to print each second pattern portion, and (c) is a diagram for explaining the relationship between the selection signal and the correction amount of the ejection amount. [Figure 8] 13 is a flowchart showing a flow of processing performed at the first startup when an unevenness correction pattern is printed again based on the result of printing the unevenness correction pattern. [Figure 9] FIG. 1A is a diagram for explaining the thinning rate of mask data used to print each first pattern portion again, FIG. 1B is a diagram for explaining the thinning rate of mask data used to print each second pattern portion again, and FIG. 1C is a diagram for explaining the relationship between the selection signal and the correction amount based on two unevenness correction patterns. [Figure 10] FIG. 1A is a diagram for explaining the relationship between the selection signal and the correction amount of the discharge amount when a correction is made to increase the discharge amount, and FIG. 1B is a diagram for explaining the relationship between the selection signal and the correction amount of the discharge amount when both a correction is made to decrease the discharge amount and a correction is made to increase the discharge amount. [Figure 11] FIG. 1A is a diagram for explaining the printing of a first pattern group using a first nozzle group, and FIG. 1B is a diagram for explaining the printing of a second pattern group and selection symbols using a second nozzle group. [Figure 12]FIG. 1A is a diagram for explaining the ratio of small balls when recording each first pattern portion when the density is changed by changing the ratio of small balls, and FIG. 1B is a diagram for explaining the ratio of small balls when recording each second pattern portion when the density is changed by changing the ratio of small balls. [Figure 13] (a) is a diagram for explaining the recording of a first pattern group when the density relationship between first pattern portions is reversed, (b) is a diagram for explaining the recording of a second pattern group when the density relationship between second pattern portions is reversed, and (c) is a diagram for explaining the recording of a selection symbol when the density relationship between first pattern portions is reversed. [Figure 14] (a) is a diagram for explaining the thinning rate of mask data used to print each first pattern portion when the density relationship between the first pattern portions is reversed, (b) is a diagram for explaining the thinning rate of mask data used to print each second pattern portion when the density relationship between the first pattern portions is reversed, and (c) is a diagram for explaining the relationship between the selection signal and the correction amount of the ejection amount when the density relationship between the first pattern portions is reversed. [Figure 15] 13A and 13B are diagrams for explaining unevenness correction patterns when a density difference is generated within a pattern portion. [Figure 16] (a) is a diagram for explaining an example of the second characteristic, (b) is a diagram for explaining another example of the second characteristic, (c) is a diagram for explaining another example of the second characteristic, and (d) is a diagram for explaining another example of the second characteristic. [Figure 17] 10 is a flowchart showing a flow of processing performed at the first startup when printing an unevenness correction pattern according to the characteristics of the inkjet head. [Figure 18] 18 is a flowchart showing the flow of a second process in FIG. 17. [Figure 19] FIG. 11 is a diagram for explaining a first unevenness correction pattern. [Figure 20](a) is a figure for explaining the recording of a first pattern group of a second unevenness correction pattern, (b) is a figure for explaining the recording of a second pattern group of a second unevenness correction pattern, and (c) is a figure for explaining the recording of selection symbols of the second unevenness correction pattern. [Figure 21] 13 is a flowchart showing the flow of a second process when a vertex detection pattern and a correction amount determination pattern are printed. [Figure 22] FIG. 1A is a diagram for explaining a pattern for detecting an apex, and FIG. 1B is a diagram for explaining a pattern for determining a correction amount. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Preferred embodiments of the present invention will now be described.

[0012] <Overall printer configuration> As shown in FIG. 1, a printer 1 according to this embodiment (the "droplet ejection device" of the present invention) includes a carriage 2, a subtank 3, an inkjet head 4 (the "droplet ejection head" of the present invention), a platen 5, transport rollers 6 and 7 (the "relative movement means" of the present invention), and a maintenance unit 8 (the "purging means" of the present invention).

[0013] The carriage 2 is supported by two guide rails 11, 12 extending in the scanning direction (the "second direction" of the present invention). The carriage 2 is connected to a carriage motor 56 (see FIG. 3) via a belt (not shown) or the like, and when the carriage motor 56 is driven, the carriage 2 moves in the scanning direction along the guide rails 11, 12. In the following description, the right and left sides of the scanning direction are defined as shown in FIG. 1.

[0014] The subtank 3 is mounted on the carriage 2. Here, the printer 1 is provided with a cartridge holder 13, in which four ink cartridges 14 ("liquid tanks" of the present invention) are removably mounted. The four ink cartridges 14 are lined up in the scanning direction, and store black, yellow, cyan, and magenta inks, starting from the one arranged on the right side in the scanning direction. The subtank 3 is connected to the four ink cartridges 14 mounted on the cartridge holder 13 via four tubes 15. In this way, the four colors of ink are supplied to the subtank 3 from the four ink cartridges 14. Note that instead of the ink cartridges 14, ink tanks fixed to the housing of the printer 1 may be provided.

[0015] The inkjet head 4 is mounted on the carriage 2 and connected to the lower end of the subtank 3. The inkjet head 4 is supplied with the four colors of ink from the subtank 3. The inkjet head 4 ejects ink droplets ("droplets" of the present invention) from a plurality of nozzles 10 formed on the lower surface, that is, the nozzle face 4a. More specifically, the nozzles 10 are arranged over a length L in a transport direction ("first direction" of the present invention) perpendicular to the scanning direction to form a nozzle row 9, and on the nozzle face 4a, four nozzle rows 9 are aligned in the scanning direction. The nozzles 10 eject black, yellow, cyan, and magenta ink droplets in that order from the nozzles constituting the nozzle row 9 on the right side of the scanning direction.

[0016] The platen 5 is disposed below the inkjet head 4 and faces the multiple nozzles 10. The platen 5 extends across the entire length of the recording paper P (the "ejection receiving medium" of the present invention) in the scanning direction, and supports the recording paper P from below.

[0017] The transport roller 6 (the "first transport roller" of the present invention) is disposed upstream in the transport direction from the inkjet head 4 and the platen 5. The transport roller 7 (the "second transport roller" of the present invention) is disposed downstream in the transport direction from the inkjet head 4 and the platen 5. In other words, the transport roller 6 and the transport roller 7 are disposed apart from each other in the transport direction, and the inkjet head 4 is located between the transport roller 6 and the transport roller 7 in the transport direction.

[0018] As shown in FIG. 2, the conveying rollers 6 are composed of a driving roller 6a and a driven roller 6b, which sandwich the recording paper P from above and below. The conveying rollers 7 are composed of a driving roller 7a and a driven roller 7b, which sandwich the recording paper P from above and below. The driving rollers 6a and 7a are connected to a conveying motor 57 (see FIG. 3) via gears (not shown). When the conveying motor 57 is driven, the driving rollers 6a and 7a rotate, and the driven rollers 6b and 7b rotate accordingly. As a result, the recording paper P sandwiched between the driving roller 6a and the driven roller 6b, and between the driving roller 7a and the driven roller 7b, is conveyed in the conveying direction.

[0019] The maintenance unit 8 includes a cap 41, a suction pump 42, and a waste liquid tank 43. The cap 41 is disposed to the right of the platen 5 in the scanning direction. When the carriage 2 is positioned at a maintenance position to the right of the platen 5 in the scanning direction, the multiple nozzles 10 face the cap 41.

[0020] The cap 41 can be raised and lowered by a cap lifting mechanism 58 (see FIG. 3). When the carriage 2 is positioned at the maintenance position so that the plurality of nozzles 10 and the cap 41 face each other, the cap 41 is raised by the cap lifting mechanism 58, and the upper end of the cap 41 comes into close contact with the nozzle surface 4a, and the plurality of nozzles 10 are covered by the cap 41. Note that the cap 41 is not limited to covering the plurality of nozzles 10 by coming into close contact with the nozzle surface 4a. The cap 41 may cover the plurality of nozzles 10 by coming into close contact with a frame (not shown) or the like that is arranged around the nozzle surface 4a of the inkjet head 4, for example.

[0021] The suction pump 42 is a tube pump or the like, and is connected to the cap 41 and the waste liquid tank 43. In the maintenance unit 8, when the suction pump 42 is driven with the plurality of nozzles 10 covered by the cap 41 as described above, so-called suction purging can be performed, in which ink is discharged from inside the inkjet head 4 through the plurality of nozzles 10. The ink discharged by the suction purging is stored in the waste liquid tank 43.

[0022] For convenience, the cap 41 covers all the nozzles 10 together, and ink in the inkjet head 4 is discharged from all the nozzles 10 during suction purge. However, the present invention is not limited to this. For example, the cap 41 may have a portion covering the nozzles 10 constituting the rightmost nozzle row 9 that ejects black ink and a portion covering the nozzles 10 constituting the three leftmost nozzle rows 9 that eject color inks (yellow, cyan, and magenta inks), and either the black ink or the color ink in the inkjet head 4 may be selectively discharged during suction purge. Alternatively, for example, the cap 41 may be provided for each nozzle row 9, and ink may be discharged from the nozzles 10 for each nozzle row 9 individually during suction purge.

[0023] <Printer electrical configuration> Next, a description will be given of the electrical configuration of the printer 1. As shown in Fig. 3, the printer 1 includes a control unit 50. The control unit 50 includes a central processing unit (CPU) 51, a read only memory (ROM) 52, a random access memory (RAM) 53, a flash memory 54, and an application specific integrated circuit (ASIC) 55. The control unit 50 controls the operations of a carriage motor 56, an inkjet head 4, a transport motor 57, a cap lifting mechanism 58, a suction pump 42, etc.

[0024] In addition to the components described above, the printer 1 also includes a display unit 60 and an operation unit 61 (the "input unit" of the present invention). The display unit 60 is, for example, a liquid crystal display provided on the housing of the printer 1. The control unit 50 controls the display unit 60 to display information necessary for the operation of the printer 1. The operation unit 61 is, for example, a button provided on the housing of the printer 1 or a touch panel provided on the display unit 60. A user can input signals by operating the operation unit 61, and the control unit 50 receives the input signals.

[0025] The control unit 50 may be one in which only the CPU 51 performs various processes, one in which only the ASIC 55 performs various processes, or one in which the CPU 51 and the ASIC 55 work together to perform various processes. The control unit 50 may be one in which one CPU 51 performs processes independently, or one in which multiple CPUs 51 share the processes. The control unit 50 may be one in which one ASIC 55 performs processes independently, or one in which multiple ASICs 55 share the processes.

[0026] <Processing at first launch> Next, a description will be given of the processing of the control unit 50 when the printer 1 is started for the first time. Here, when the printer 1 is manufactured, a storage liquid is filled in place of ink in the inkjet head 4. The storage liquid is, for example, a liquid obtained by removing the coloring material from the ink.

[0027] Furthermore, in the inkjet head 4, variations in the amount of ink droplets ejected may occur among the multiple nozzles 10 constituting the nozzle row 9 due to the influence of manufacturing errors, etc. The variation in the amount of ink droplets ejected refers to differences in the amount of ink droplets ejected when the inkjet head 4 is driven by the same signal to eject ink droplets from the nozzles 10.

[0028] For example, as shown in FIG. 4(a), the inkjet head 4 may have a characteristic that, when the inkjet head 4 is driven with the same signal to eject ink droplets from each of the multiple nozzles 10 constituting a nozzle row 9, the amount of ink droplets ejected gradually increases from the most upstream nozzle 10a in the transport direction (the "first nozzle at the outermost end in one of the first directions" of the present invention) toward the most downstream nozzle 10b (the "second nozzle at the outermost end in the other direction of the first direction" of the present invention).

[0029] Alternatively, as shown in FIG. 4(b), when the inkjet head 4 is driven with the same signal to eject ink droplets from each of the multiple nozzles 10 that make up the nozzle row 9, the amount of ink droplets ejected may gradually decrease from nozzle 10a to nozzle 10b in the transport direction.

[0030] Therefore, in this embodiment, when the printer 1 is used for the first time, the control unit 50 performs processing in accordance with the flow of FIG. 5 to discharge the storage liquid in the inkjet head 4 and introduce ink into the inkjet head 4 (initial introduction), and also corrects the amount of ink droplets ejected from the nozzle 10.

[0031] 5, the control unit 50 first executes an initial introduction process (S101). In the initial introduction process, the control unit 50 controls the suction pump 42 and the like to perform suction purging, thereby discharging the preservative in the inkjet head 4 and introducing ink from the ink cartridge 14 into the inkjet head 4, thereby performing initial introduction.

[0032] Next, the control unit 50 executes a paper feed process (S102). In the paper feed process, the control unit 50 controls a paper feed mechanism (not shown) to feed the recording paper P, and controls the conveying motor 57 to convey the recording paper P to the conveying rollers 6 and 7 to a position where the recording paper P is sandwiched between the conveying rollers 6 and 7 as shown in FIGS. 1 and 2.

[0033] Next, the control unit 50 executes a first pattern group recording process (S103). In the first pattern group recording process, the control unit 50 controls the carriage motor 56 to move the carriage 2 in the scanning direction, while controlling the inkjet head 4 to perform a recording pass in which ink droplets are ejected from the multiple nozzles 10, thereby recording a first pattern group 71 as shown in FIG. 6(a) on the recording paper P. At this time, the first pattern group 71 is recorded for each of the black, yellow, cyan, and magenta inks. However, since the first pattern group 71 for each color is the same except for the color of the ink, only the first pattern group 71 for one color is illustrated and described in FIG. 6(a). The same applies to other pattern groups, unevenness correction patterns, etc. in the following description.

[0034] First pattern group 71 is composed of a plurality of first pattern portions 72A-72I arranged adjacent to each other in the scanning direction. First pattern portions 72A-72I are rectangular fill patterns. In this embodiment, among first pattern portions 72A-72I, first pattern portion 72E located at the center in the scanning direction corresponds to the "reference first pattern portion" of the present invention. Also, first pattern portion 72I at the right end corresponds to the "first pattern portion at the outermost end on one side in the second direction" of the present invention. Also, first pattern portion 72A at the left end corresponds to the "first pattern portion at the outermost end on the other side in the second direction" of the present invention.

[0035] Furthermore, in the first pattern group recording process, the control unit 50 causes all of the nozzles 10 constituting the nozzle row 9 to eject ink droplets in a recording pass, thereby recording the first pattern portions 72A to 72I on the recording paper P.

[0036] Furthermore, in the first pattern group recording process, the control unit 50 records the first pattern portions 72A-72E so that the first pattern portion 72E and the first pattern portions 72A-72D to the left of the first pattern portion 72E (further from the first pattern portion 72I) have the same density. The control unit 50 also records the first pattern portions 72F-72I so that the first pattern portions 72F-72I to the right of the first pattern portion 72E (further from the first pattern portion 72A) have a lower density than the first pattern portion 72E, and so that the density of the first pattern portions closer to the right end becomes lighter.

[0037] Returning to FIG. 5, the control unit 50 then executes a conveying process (S104). In the conveying process of S104, the control unit 50 controls the conveying motor 57 to make the conveying rollers 6 and 7 convey the recording paper P in the conveying direction of the length L of the nozzle row 9. Here, in this embodiment, in S102, the conveying rollers 6 and 7 convey the recording paper P so that the recording paper P is in a position where it is sandwiched between both of the conveying rollers 6 and 7 even after the conveying process of S104.

[0038] Next, the control unit 50 executes a second pattern group recording process (S105). In the second pattern group recording process, the control unit 50 performs a recording pass to record a second pattern group 81 as shown in FIG. 6(b) on the recording paper P.

[0039] The second pattern group 81 is composed of a plurality of second pattern portions 82A-82I arranged adjacent to each other in the scanning direction. The second pattern portions 82A-82I are rectangular fill-in patterns. The second pattern portions 82A-82I are arranged adjacent to each other on the upstream side in the transport direction of the first pattern portions 72A-72I, respectively. As a result, the portions of the first pattern portions 72A-72I recorded by nozzle 10a and the portions of the second pattern portions 82A-82I recorded by nozzle 10b are adjacent to each other in the transport direction.

[0040] In this embodiment, among second pattern portions 82A-82I, second pattern portion 82E located in the center in the scanning direction corresponds to the "reference second pattern portion" of the present invention. Second pattern portion 82I at the right end corresponds to the "second pattern portion at the outermost end on one side in the second direction" of the present invention. Second pattern portion 82A at the left end corresponds to the "second pattern portion at the outermost end on the other side in the second direction" of the present invention.

[0041] Moreover, in the second pattern group recording process, the control unit 50 causes the second pattern portions 82A to 82I to be recorded on the recording paper P by ejecting ink droplets from all of the nozzles 10 constituting the nozzle row 9 in a recording pass.

[0042] In the second pattern group recording process, the control unit 50 records the second pattern portions 82E-82I so that the second pattern portion 82E and the second pattern portions 82F-82I to the right of the second pattern portion 82E (further from the second pattern portion 82A) have the same density. In addition, the control unit 50 records the second pattern portions 82E-82I so that the density of the second pattern portions 82E-82I is the same as the density of the first pattern portions 72A-72E, assuming that there is no variation in the amount of ink droplets discharged between the multiple nozzles 10 constituting the nozzle row 9. In addition, the control unit 50 records the second pattern portions 82A-82D so that the second pattern portions 82A-82D to the left of the second pattern portion 82E (further from the second pattern portion 82I) have a lower density than the second pattern portion 82E, and the density of the second pattern portions closer to the left end becomes lower.

[0043] In this embodiment, the unevenness correction pattern 70 having the first pattern group 71 and the second pattern group 81 is printed in the above manner.

[0044] Here, a method for recording the first pattern portions 72A-72I and the second pattern portions 82A-82I so as to have the above-mentioned densities will be described. In this embodiment, when ink droplets are ejected from the multiple nozzles 10 in a recording pass, the control unit 50 generates ejection data indicating the timing of ejection of ink droplets from each nozzle 10 in the recording pass, based on image data of an image to be recorded. In addition, the control unit 50 ejects ink droplets from the multiple nozzles 10 while thinning out some of the ink droplets ejected according to the ejection data, based on mask data, thereby reducing the amount of ink droplets ejected per unit area in the first pattern portion, thereby reducing the density.

[0045] At this time, the control unit 50 can selectively use one of a plurality of types of mask data with different thinning rates to thin out a portion of the ejection of ink droplets indicated by the ejection data. The thinning rate is the ratio of the ejection of ink droplets to be thinned out of the ejection of ink droplets indicated by the ejection data. The plurality of types of mask data are generated by the control unit 50 itself, or are stored in advance in the flash memory 54.

[0046] 7(a) and (b), when printing first pattern portions 72A-72E and second pattern portions 82E-82I, mask data with a thinning rate of 0 is used. In other words, first pattern portions 72A-72E and second pattern portions 82E-82I are printed without thinning out the ink droplets ejected from the multiple nozzles 10.

[0047] 7(a), when first pattern portions 72F, 72G, 72H, and 72I are printed, mask data with thinning rates of M, (2×M), (3×M), and (4×M) are used, respectively. That is, among first pattern portions 72F to 72I, the closer to the right end the first pattern portion is, the higher the thinning rate is used for the printed first pattern portion.

[0048] 7(b), when recording second pattern portions 82A, 82B, 82C, and 82D, mask data with thinning rates of (4×M), (3×M), (2×M), and M are used, respectively. That is, of the second pattern portions 82A to 82D, the second pattern portions closer to the left end are recorded using mask data with a higher thinning rate.

[0049] Next, the control unit 50 executes a conveying process (S106). In the conveying process of S106, the control unit 50 controls the conveying motor 57 to make the conveying rollers 6 and 7 convey the recording paper P. The conveying amount of the recording paper P at this time may be the same as the length L of the nozzle row 9, or may be different from the length L.

[0050] Next, the control unit 50 executes a selection symbol recording process (S107). In the selection symbol recording process, the control unit 50 executes a recording pass to record a plurality of selection symbols 73 for allowing a user to select a pattern set 74, which is a set of a first pattern portion and a second pattern portion aligned in the transport direction, as shown in FIG. 6(c).

[0051] Next, the control unit 50 executes the paper discharge process (S108). In the paper discharge process, the control unit 50 controls the conveyance motor 57 to convey the recording paper P to the conveyance rollers 6 and 7, thereby discharging the recording paper P.

[0052] Next, the control unit 50 causes the display unit 60 to display a selection screen for prompting the user to select the pattern set 74 having the smallest density difference at the boundary between the first pattern portion and the second pattern portion (S109). Then, the user operates the operation unit 61 to input a selection signal for selecting the pattern set 74, and the control unit 50 waits until it receives this selection signal (S110: NO). In this embodiment, the information on the position of the pattern set 74 in the scanning direction indicated by the selection signal corresponds to the "information on the density optimum position" of the present invention.

[0053] Then, when the control unit 50 receives the selection signal (S110: YES), it executes a correction process (S111). In the correction process, the control unit 50 corrects the amount of ink droplets ejected from the nozzles 10 based on the selection signal. The correction of the amount of ink droplets ejected from the nozzles 10 is performed, for example, by correcting the waveform of the drive signal that drives the inkjet head 4.

[0054] To explain the correction of the amount of ink droplets ejected in more detail, as shown in FIG. 7(c), when the selection signal indicates a pattern set 74 of the first pattern portion 72E and the second pattern portion 82E ("E" is selected), the amount of ink droplets ejected from the nozzle 10 is not corrected (the correction amount is set to ±0).

[0055] Furthermore, when the selection signal indicates a pattern set 74 on the left side of the pattern sets 74 of the first pattern portion 72E and the second pattern portion 82E (one of "A" to "D" is selected), a correction is made to reduce the amount of ink droplets ejected from nozzle 10b or a predetermined number of nozzles 10 arranged in succession including nozzle 10b (hereinafter, these may be collectively referred to as "downstream nozzles"). At this time, a correction is made to reduce the amount of ink droplets ejected from downstream nozzles, the closer the pattern set 74 indicated by the selection signal is to the left end. Note that "-" in FIG. 6(c) means that the amount of ejection is reduced.

[0056] In addition, the amount of ink droplets ejected from the downstream nozzles after the correction amounts "A" to "D" shown in Figure 6(c) are the same as the amount of ink droplets ejected from the downstream nozzles when recording the second pattern portions 82A to 82D, respectively.

[0057] Furthermore, when the selection signal indicates a pattern set 74 to the right of the pattern sets 74 of the first pattern portion 72E and the second pattern portion 82E (any of "F" to "I" is selected), a correction is made to reduce the amount of ink droplets ejected from the nozzle 10a or a predetermined number of nozzles 10 arranged in succession including the nozzle 10a (hereinafter, these may be collectively referred to as "upstream nozzles"). At this time, a correction is made to reduce the amount of ink droplets ejected from the upstream nozzles, the closer the pattern set 74 indicated by the selection signal is to the right end.

[0058] Furthermore, the ink droplet ejection amounts from the upstream nozzles after the correction amounts "F" to "I" shown in Figure 6(c) are the same as the ink droplet ejection amounts from the upstream nozzles when recording the first pattern portions 72F to 72I, respectively.

[0059] <Effects> In this embodiment, the first pattern portions 72A-72E have the same density, the first pattern portions 72F-72I have a lower density than the first pattern portions 72A-72E, and the first pattern portions closer to the right end have a lower density. The second pattern portions 82E-82I have the same density, the second pattern portions 82A-82D have a lower density than the second pattern portions 82E-82I, and the second pattern portions closer to the left end have a lower density.

[0060] Therefore, if there is no difference in the discharge amount between the nozzle 10a and the nozzle 10b, the density difference at the boundary between the first pattern portion and the second pattern portion in the pattern set 74 of the first pattern portion 72E and the second pattern portion 82E is the smallest. On the other hand, if the amount of ink droplets discharged from the nozzle 10b is greater than the amount of ink droplets discharged from the nozzle 10a, the density difference at the boundary between the first pattern portion and the second pattern portion in the pattern set 74 on the left side of the pattern set 74 of the first pattern portion 72E and the second pattern portion 82E is the smallest. Also, if the amount of ink droplets discharged from the nozzle 10b is less than the amount of ink droplets discharged from the nozzle 10a, the density difference at the boundary between the first pattern portion and the second pattern portion in the pattern set 74 on the right side of the pattern set 74 of the first pattern portion 72E and the second pattern portion 82E is the smallest.

[0061] Therefore, by setting the amount of ink droplets ejected from the upstream nozzle or the downstream nozzle to the amount of ink droplets ejected when printing the pattern set 74 having the smallest density difference at the boundary between the first pattern portion and the second pattern portion, it is possible to reduce variation in the amount of ink droplets ejected between the nozzles 10.

[0062] Furthermore, in this embodiment, by simply having the user select the pattern set 74 with the smallest density difference at the boundary between the first pattern portion and the second pattern portion, the amount of ink droplets ejected from the nozzles 10 can be corrected according to the selection result, thereby reducing the variation in the amount of ink droplets ejected between the nozzles 10. Therefore, in this embodiment, there is no need for a scanner or the like for reading the unevenness correction pattern and acquiring density information, and the variation in the amount of ink droplets ejected from the nozzles 10 can be easily reduced.

[0063] In this embodiment, the first pattern group 71 has a plurality of first pattern portions 72A-72D and a plurality of first pattern portions 72F-72I on the left and right sides, respectively, of the first pattern portion 72E. That is, the first pattern group 71 has the first pattern portions 72B-72D between the first pattern portion 72A and the first pattern portion 72E, and has the first pattern portions 72F-72H between the first pattern portion 72E and the first pattern portion 72I.

[0064] Similarly, the second pattern group 81 has a plurality of second pattern portions 82A-82D and a plurality of second pattern portions 82F-82I on the left and right sides, respectively, of the second pattern portion 82E. That is, the second pattern group 81 has the second pattern portions 82B-82D between the second pattern portion 82A and the second pattern portion 82E, and has the second pattern portions 82F-82H between the second pattern portion 82E and the second pattern portion 82I.

[0065] For these reasons, in this embodiment, the first pattern group 71 has a plurality of first pattern portions 72F-72I in which the density is changed in multiple stages with respect to the first pattern portion 72E, and the second pattern group 81 has a plurality of second pattern portions 82A-72D in which the density is changed in multiple stages with respect to the second pattern portion 82E, and the amount of ink droplets ejected from the upstream nozzles or downstream nozzles can be corrected in multiple stages. This makes it possible to accurately reduce the variation in the amount of ink droplets ejected between the nozzles 10.

[0066] In this embodiment, the amount of ink droplets ejected per unit area when recording first pattern portions 72A-72E is the same, and the amount of ink droplets ejected per unit area when recording first pattern portions 72F-72I is made smaller than that when recording first pattern portions 72A-72E, and the amount of ink droplets ejected per unit area is made smaller when recording first pattern portions closer to the right end. This makes the density of first pattern portions 72F-72I lighter than that of first pattern portions 72A-72E, and the density of first pattern portions closer to the right end can be made lighter.

[0067] In this embodiment, the amount of ink droplets ejected per unit area when recording second pattern portions 82E-82I is the same, and the amount of ink droplets ejected per unit area when recording second pattern portions 82A-82D is made smaller than the amount of ink droplets ejected per unit area when recording second pattern portions 82E-82I, and the amount of ink droplets ejected per unit area when recording second pattern portions closer to the left end is made smaller. This makes the density of second pattern portions 82A-82D lighter than the density of second pattern portions 82E-82I, and the density of second pattern portions closer to the left end is made lighter.

[0068] In this embodiment, the first pattern portions 72A-72E are printed using the same mask data, and when printing the first pattern portions 72F-72I, mask data with a higher thinning rate than that used when printing the first pattern portions 72A-72E is used, and the closer to the right end of the first pattern portion is printed, the higher the thinning rate of the mask data used. This makes it possible to print the first pattern portions 72F-72I with a smaller ejection amount per unit area than that used when printing the first pattern portions 72A-72E, and to print the first pattern portions closer to the right end with a smaller ejection amount per unit area.

[0069] In this embodiment, the second pattern portions 82E-82I are printed using the same mask data, and when printing the second pattern portions 82A-82D, mask data with a higher thinning rate than that used when printing the second pattern portions 82E-82I is used, and the closer to the left end of the second pattern portions, the closer to the left end of the second pattern portions, the smaller the ejection amount per unit area when printing the second pattern portions 82A-82D, compared to that used when printing the second pattern portions 82E-82I, and the closer to the left end of the second pattern portions, the smaller the ejection amount per unit area.

[0070] Furthermore, in this embodiment, the unevenness correction pattern 70 (the first pattern group 71 and the second pattern group 81) is recorded in a stable state in which the recording paper P is sandwiched between both the transport roller 6 and the transport roller 7. This makes it possible to prevent the positions of the first pattern portions 72A-72I and the second pattern portions 82A-82I on the recording paper P from shifting.

[0071] Furthermore, in this embodiment, the variation in the amount of ink droplets ejected from the nozzles 10 can be reduced by correcting the amount of ink droplets ejected from the nozzles 10 based on a selection signal input by the user operating the operation unit 61.

[0072] Furthermore, in this embodiment, the unevenness correction pattern 70 is printed immediately after the initial installation is completed. Therefore, by correcting the amount of ink droplets ejected from the nozzles 10 based on the printing result of the unevenness correction pattern 70, it is possible to reduce the variation in the amount of ink droplets ejected between the nozzles 10 from the first time the printer 1 is used.

[0073] <Modification> Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments, and various modifications are possible within the scope of the claims.

[0074] For example, in the first modification, when the printer 1 is started for the first time, the control unit 50 performs processing according to the flow of FIG. 8. More specifically, the control unit 50 performs an initial installation process similar to S101 similar to the above-mentioned embodiment (S201), and then sets the thinning interval to M (S202). Here, the thinning interval refers to the difference in the thinning rate of the mask data used between adjacent first pattern portions 72E-72I and between adjacent second pattern portions 82E-82I. Then, the control unit 50 performs the processes of S203 to S211 similar to S102 to S110 in the above-mentioned embodiment.

[0075] As a result, when the first pattern group 71 is printed in S204, the first pattern portions 72A-72I are printed using mask data with a thinning rate as shown in Fig. 7(a) as in the above-described embodiment. Also, when the second pattern group 81 is printed in S206, the second pattern portions 82A-82I are printed using mask data with a thinning rate as shown in Fig. 7(b) as in the above-described embodiment.

[0076] Then, when a selection signal is received (S211: YES), the control unit 50 sets the first and second pattern parts constituting the pattern set 74 indicated by the selection signal as the first and second pattern parts to be recorded in the center in the scanning direction in S215 and S217 described later (S212). That is, the first and second pattern parts are reset to the reference first and second pattern parts.

[0077] Next, the control unit 50 sets the thinning interval to [(1 / 4)×M], which is smaller than M set in S202 (S213), and then executes the processes of S214 to S222, which are similar to S102 to S110 in the above embodiment.

[0078] 9A, the thinning rate of the mask data used to record the first pattern portion constituting the pattern set 74 indicated by the selection signal received in S211 is set to M1, and when recording the first pattern portions 72A to 72E in S215, mask data with a thinning rate of M1 is used. Also, when recording the first pattern portions 72F, 72G, 27H, and 72I, mask data with thinning rates of [M1+(1 / 4)×M], [M1+(1 / 2)×M], [M1+(3 / 4)×M], and [M1+M] are used, respectively.

[0079] 9B, when the second pattern portions 82E to 82I are recorded in S217, mask data with a thinning rate of M2 is used. When the second pattern portions 82D, 82C, 82B, and 82A are recorded, mask data with thinning rates of [M2+(1 / 4)×M], [M2+(1 / 2)×M], [M2+(3 / 4)×M], and [M2+M] are used, respectively.

[0080] As a result, in the unevenness correction pattern 70 recorded by S214 to S217, the density of the first pattern portion 71E and the second pattern portion 82E constituting the pattern set 74 at the center in the scanning direction becomes the same as the density of the first pattern portion and the second pattern portion constituting the pattern set 74 corresponding to the selection signal received in S211 in the unevenness correction pattern 70 recorded by S203 to S206. Also, in the unevenness correction pattern 70 recorded by S214 to S217, the density differences among the first pattern portions 72A to 72E, 72F, 72G, 72H, and 72I and the density differences among the second pattern portions 82A, 82B, 82C, 82D, and 82E to 82I become smaller than in the unevenness correction pattern 70 recorded by S203 to S206.

[0081] Then, when the selection signal is received (S222: YES), the control unit 50 executes the correction process (S223). Here, in the first modification, as shown in FIG. 9(c), a table is stored in which the selection signal ("A" to "I") received in S211 and the selection signal ("A" to "I") received in S222 are associated with the correction amount of the ink droplet ejection amount. In the correction process of S223, the correction amount is determined based on the selection signals received in S211 and S222 and FIG. 9(c), and the ejection amount of ink droplets from the upstream nozzle or the downstream nozzle is corrected. The correction amount shown in FIG. 9(c) is the sum of the correction amount determined based on the selection signal received in S211 and the correction amount determined based on the selection signal received in S222.

[0082] In the first modification, the unevenness correction pattern 70 is recorded based on the recording result of the unevenness correction pattern 70, and in the re-recorded unevenness correction pattern 70, the density differences between the first pattern portions 72A-72E, 72F, 72G, 72H, and 72I and the density differences between the second pattern portions 82A, 82B, 82C, 82D, and 82E-82I are made smaller than those in the previously recorded unevenness correction pattern 70. This makes it possible to accurately correct the variation in the amount of ink droplets ejected between the nozzles 10 based on the recording result of the previously recorded unevenness correction pattern 70 and the recording result of the re-recorded unevenness correction pattern.

[0083] In the first modification, the thinning interval is set to "(1 / 4) × M" in S213, and the adjustment correction amount is set to be as shown in Figs. 9(c) to (e) accordingly. However, this is not limiting. The thinning interval may be set to another thinning interval smaller than M in S213, and the adjustment correction amount may be set accordingly.

[0084] In the above embodiment, when the selection signal indicates a pattern set 74 on the left side of the first pattern portion 72E and the second pattern portion 82E, the ejection amount is corrected to reduce the amount of ink droplets ejected from the downstream nozzle. When the selection signal indicates a pattern set 74 on the right side of the first pattern portion 72E and the second pattern portion 82E, the ejection amount is corrected to reduce the amount of ink droplets ejected from the upstream nozzle. However, this is not limited to the above.

[0085] In variant example 2, as shown in FIG. 10(a), when the selection signal indicates a pattern set to the left of the first pattern portion 72E and the second pattern portion 82E (one of "A" to "D" is selected), the amount of ink droplets ejected from the upstream nozzle is increased, and the ejection amount is corrected so that the amount of ink droplets ejected from the upstream nozzle increases as the pattern set 74 indicated by the selection signal is the pattern set 74 closer to the left end.

[0086] In addition, when the selection signal indicates a pattern set 74 to the right of the first pattern portion 72E and the second pattern portion 82E (either "F" to "I" is selected), the amount of ink droplets ejected from the downstream nozzle is increased, and the ejection amount is corrected so that the closer the pattern set 74 indicated by the selection signal is to the right end, the greater the amount of ink droplets ejected from the downstream nozzle.

[0087] 10(b), when the selection signal indicates a pattern set 74 on the left side of the first pattern portion 72E and the second pattern portion 82E (one of "A" to "D" is selected), the ejection amount is corrected so that the amount of ink droplets ejected from the upstream nozzles is increased and the amount of ink droplets ejected from the downstream nozzles is decreased. Furthermore, when the pattern set 74 indicated by the selection signal is a pattern set 74 closer to the left end, the ejection amount is corrected so that the amount of ink droplets ejected from the upstream nozzles is increased and the amount of ink droplets ejected from the downstream nozzles is decreased.

[0088] Furthermore, when the selection signal indicates a pattern set 74 to the right of the first pattern portion 72E and the second pattern portion 82E (one of "F" to "I" is selected), the ejection amount is corrected to reduce the amount of ink droplets ejected from the upstream nozzles and increase the amount of ink droplets ejected from the downstream nozzles. Furthermore, the closer the pattern set 74 indicated by the selection signal is to the right end, the smaller the amount of ink droplets ejected from the upstream nozzles and the larger the amount of ink droplets ejected from the downstream nozzles. However, in the third modification, the magnitude of the correction amount of the ejection amount for the upstream nozzles and the downstream nozzles is half that in the above-mentioned embodiment.

[0089] By correcting the amount of ink droplets ejected from the nozzle 10b or from both the nozzles 10a and 10b as in the second and third modified examples, the variation in the amount of ink droplets ejected between the nozzles 10 can also be reduced.

[0090] Furthermore, in the above embodiment, the first pattern group 71 and the second pattern group 81 are recorded by ejecting ink droplets from all of the nozzles 10 that configure the nozzle row 9, but the present invention is not limited to this.

[0091] In the fourth modification, as shown in FIGS. 11(a) and 11(b), the nozzle row 9 has a first nozzle group 100a, a second nozzle group 100b, and a third nozzle group 100c. The first nozzle group 100a is composed of a plurality of nozzles 10 including the nozzle 10a and arranged continuously in the transport direction. The second nozzle group 100b is composed of a plurality of nozzles 10 including the nozzle 10b and arranged continuously in the transport direction. The third nozzle group 100c is located between the first nozzle group 100a and the second nozzle group 100b in the transport direction and is composed of a plurality of nozzles 10 arranged continuously in the transport direction. Thus, in the fourth modification, the first nozzle group 100a is composed of some of the nozzles 10 in the nozzle row 9, including the nozzle 10a, arranged continuously on the upstream side of the nozzle 10 located at the center in the transport direction. Also, the second nozzle group 100b is composed of some of the nozzles 10 in the nozzle row 9, including the nozzle 10b, arranged continuously on the downstream side of the nozzle 10 located at the center in the transport direction.

[0092] In the fourth modification, as shown in FIG. 11(a), ink droplets are ejected from the nozzles 10 constituting the first nozzle group 100a to record the first pattern group 102. Also, as shown in FIG. 11(b), ink droplets are ejected from the nozzles 10 constituting the second nozzle group 100b to record the second pattern group 103. This allows the unevenness correction pattern 101 having the first pattern group 102 and the second pattern group 103 to be recorded. Also, in the recording pass for recording the second pattern group 103, ink droplets are ejected from the nozzles 10 constituting at least one of the first nozzle group 100a and the third nozzle group 100c to record the selection symbol 104. Note that the selection symbol 104 may be recorded in a recording pass other than the recording pass for recording the second pattern group 103, as in the above embodiment.

[0093] In the fourth modification, the first nozzle group 100a ejects ink droplets to print the first pattern group 102, and the second nozzle group 100b ejects ink droplets to print the second pattern group 103, so that the first pattern group 102 and the second pattern group 103 can each be printed in one printing pass and have a certain length in the transport direction. This makes it possible to make the unevenness correction pattern 101 easier to see.

[0094] Furthermore, in the fourth modification, the first nozzle group 100a ejects ink droplets to print the first pattern group 102, and the second nozzle group 100b ejects ink droplets to print the second pattern group 103, thereby preventing the nozzles 10 used to print the first pattern group 102 from overlapping with the nozzles 10 used to print the second pattern group 103. This makes it possible to reduce the amount of ink droplets consumed in printing the unevenness correction pattern 101.

[0095] Furthermore, in the fourth modification, the nozzle array 9 has a third nozzle group 100c, which is not used for recording either the first pattern group 102 or the second pattern group 103, between the first nozzle group 100a used for recording the first pattern group 102 and the second nozzle group 100b used for recording the second pattern group 103. This makes it possible to reduce the amount of ink consumed in recording the unevenness correction pattern 101, compared to a case in which the nozzle array 9 does not have nozzles 10 that are not used for recording either the first pattern group 102 or the second pattern group 103.

[0096] In addition, in the fourth modified example, the nozzle row 9 has the third nozzle group 100c between the first nozzle group 100a and the second nozzle group 100b, the third nozzle group 100c being composed of a plurality of nozzles 10 aligned continuously in the transport direction, but this is not limited thereto. The nozzle row 9 may have only one nozzle 10 between the first nozzle group 100a and the second nozzle group 100b.

[0097] Furthermore, the nozzle array 9 is not limited to having nozzles 10 that are not used for recording either the first pattern group 102 or the second pattern group 103. For example, the first nozzle group used for recording the first pattern group may be formed by the upstream half of the nozzle array 9 in the transport direction, and the second nozzle group used for recording the second pattern group may be formed by the downstream half of the nozzle array 9 in the transport direction.

[0098] Furthermore, when the first and second pattern groups are printed using nozzles 10 that form part of the nozzle row 9, the nozzles 10 used to print the first pattern group and the nozzles 10 used to print the second pattern group may partially overlap.

[0099] Furthermore, the first and second pattern groups may not necessarily be recorded by ejecting ink droplets from a plurality of nozzles 10 arranged in succession. For example, the first pattern group may be recorded using only nozzle 10a. Also, the second pattern group may be recorded using only nozzle 10b. In these cases, the first and second pattern groups having a certain length in the transport direction may be recorded by repeating a printing pass and a transport operation.

[0100] In the above embodiment, the thinning rate of the mask data is changed to change the amount of ink droplets ejected per unit area, thereby varying the density of the pattern portion, but the present invention is not limited to this.

[0101] In the fifth modification, the inkjet head 4 can selectively eject from each nozzle 10 one of two types of ink droplets having different volumes: a large droplet and a small droplet having a smaller volume than the large droplet.

[0102] In variant example 5, as shown in Figures 12(a) and (b), when recording the first pattern portions 72A-72E and the second pattern portions 82E-82I, the ratio of small droplets is set to 0, i.e., all ink droplets ejected from nozzles 10 are large droplets.

[0103] Also, as shown in Fig. 12(a), when recording the first pattern portions 72F to 72I, the ratios of the small dots are set as R1, R2, R3, and R4 respectively. Here, R1 to R4 are in the relationship of R1 < R2 < R3 < R4. That is, when recording the first pattern portions 72F to 72I, the ratio of the small dots is made higher than when recording the first pattern portions 72A to 72E, and the ratio of the small dots becomes higher as the first pattern portion closer to the right end is recorded.

[0104] Also, as shown in Fig. 12(b), when recording the second pattern portions 82A to 82D, the ratios of the small dots are set as R4, R3, R1, and R1 respectively. That is, when recording the second pattern portions 82A to 82D, the ratio of the small dots is made higher than when recording the second pattern portions 82E to 82I, and the ratio of the small dots becomes higher as the second pattern portion closer to the left end is recorded.

[0105] In Modification 5, by setting the ratio of the small dots when recording the first pattern portions 72A to 72I as described above, the discharge amount per unit area when recording the first pattern portions 72F to 72I can be made less than that when recording the first pattern portions 72A to 72E, and the discharge amount per unit area can be made less for the first pattern portion closer to the right end.

[0106] Also, in Modification 5, by setting the ratio of the small dots when recording the second pattern portions 82A to 82I as described above, the discharge amount per unit area when recording the second pattern portions 82A to 82D can be made smaller than that when recording the second pattern portions 82E to 82I, and the discharge amount per unit area can be made less for the second pattern portion closer to the left end.

[0107] Also, by methods other than changing the thinning rate of the mask data and changing the ratio of the small dots, the magnitude relationship of the densities of the first pattern portions 72A to 72I and the magnitude relationship of the densities of the second pattern portions 82A to 82I may be as described above.

[0108] For example, the above-mentioned relationship in density between first pattern portions 72A to 72I may be achieved by differentiating image data for printing the first pattern portions among first pattern portions 72A to 72E, 72F, 72G, 72H, and 72I. Similarly, the above-mentioned relationship in density between second pattern portions 82A to 82I may be achieved by differentiating image data for printing the second pattern portions among second pattern portions 82A, 82B, 82C, 82D, and 82E to 82I.

[0109] Furthermore, the magnitude relationship of the densities of the first pattern portions 72A-72I in the first pattern group 71 and the magnitude relationship of the densities of the second pattern portions 82A-82I in the second pattern group 81 are not limited to those in the above-described embodiment.

[0110] In the sixth modification, when the printer 1 is first started, the control unit 50 also performs the process according to the flow of Fig. 5. However, in the sixth modification, the processes of S103, S105, and S111 are different from those in the above-described embodiment.

[0111] In the sixth modification, in the first pattern group recording process of S103, the control unit 50 causes a recording pass to be performed, thereby recording a first pattern group 111 as shown in FIG. 13(a) on the recording paper P. In the sixth modification, as shown in FIG.

[0112] First pattern group 111 is composed of multiple first pattern portions 112A-112I arranged adjacent to each other in the scanning direction. First pattern portions 112A-112I are rectangular fill-in patterns. In Modification 6, first pattern portion 112E located in the center in the scanning direction corresponds to the "reference first pattern portion" of the present invention. Also, first pattern portion 112I corresponds to the "first pattern portion at the outermost end on one side in the second direction" of the present invention. Also, first pattern portion 112A corresponds to the "first pattern portion at the outermost end on the other side in the second direction" of the present invention.

[0113] Furthermore, in the first pattern group recording process, the control unit 50 records the first pattern portions 112A-112E so that the first pattern portion 112E and the first pattern portions 112A-112D located to the left of the first pattern portion 112E have the same density. The control unit 50 also records the first pattern portions 112F-112I so that the density of the first pattern portions 112F-112I located to the right of the first pattern portion 112E is darker than the density of the first pattern portion 112E, and the closer to the right end (the farther from the first pattern portion 112A) the darker the first pattern portion is.

[0114] 14(a), for example, mask data with a thinning rate of (4×M) is used when printing first pattern portions 112A to 112E, and mask data with thinning rates of (3×M), (2×M), M, and 0 are used when printing first pattern portions 112F, 112G, 112H, and 112I, respectively.

[0115] In the second pattern group recording process of S105, the control unit 50 performs a recording pass to record a second pattern group 121 as shown in FIG. 13(b).

[0116] The second pattern group 121 is composed of a plurality of second pattern portions 122A-122I arranged adjacent to each other in the scanning direction. The second pattern portions 122A-122I are rectangular fill-in patterns. The second pattern portions 122A-122I are arranged adjacent to each other on the upstream side in the transport direction of the first pattern portions 112A-112I, respectively. As a result, the portions of the first pattern portions 112A-112I recorded by the nozzle 10a and the portions of the second pattern portions 122A-122I recorded by the nozzle 10b are adjacent to each other in the transport direction.

[0117] In the second pattern group recording process, the control unit 50 records the second pattern portions 122E-122I so that the second pattern portion 122E and the second pattern portions 122F-122I located to the right of the second pattern portion 122E have the same density. In addition, the control unit 50 records the second pattern portions 122E-122I so that the density of the second pattern portions 122E-122I is the same as the density of the first pattern portions 112A-112E, assuming that there is no variation in the amount of ink droplets discharged between the multiple nozzles 10 constituting the nozzle row 9. In addition, the control unit 50 records the second pattern portions 122A-122D so that the density of the second pattern portions 122A-122D located to the left of the second pattern portion 122E is higher than the density of the second pattern portion 122E, and the closer to the left end (the further away from the second pattern portion 122I) the higher the density.

[0118] 14(b), for example, mask data with thinning rates of 0, M, (2×M), and (3×M) are used when recording second pattern portions 122A, 122B, 122C, and 122D, respectively, and mask data with a thinning rate of (4×M) is used when recording second pattern portions 122E to 122I.

[0119] Then, by recording the first pattern group 111 and the second pattern group 121 as described above, it is possible to record the unevenness correction pattern 110 having the first pattern group 111 and the second pattern group 121. Also in the sixth modification, in S107, as shown in Fig. 13(c), a selection symbol 113 is recorded for each pattern set 114 of the first pattern portion and the second pattern portion aligned in the transport direction.

[0120] In the correction process of S111, when the selection signal indicates a pattern set 114 of the first pattern portion 112E and the second pattern portion 122E ("E" is selected), as shown in FIG. 14(c), the control unit 50 does not correct the amount of ink droplets ejected from the nozzle 10.

[0121] Furthermore, when the selection signal indicates a set on the left side of pattern set 114 of first pattern portion 112E and second pattern portion 122E (one of "A" to "D" is selected), a correction is made to increase the amount of ink droplets ejected from the downstream nozzle. At this time, the closer to the left end the pattern set 114 indicated by the selection signal is, the greater the amount of ink droplets ejected from the downstream nozzle is.

[0122] Furthermore, when the selection signal indicates a pattern set 114 on the right side of the pattern sets 114 of the first pattern portion 112E and the second pattern portion 122E (one of "F" to "I" is selected), a correction is made to increase the amount of ink droplets ejected from the upstream nozzles. Also, at this time, the closer the pattern set 114 indicated by the selection signal is to the right end, the more the amount of ink droplets ejected from the upstream nozzles is increased.

[0123] In variant example 6, the variation in the amount of ink droplets ejected between nozzles 10 can also be reduced by correcting the amount of ink droplets ejected from upstream nozzles including nozzle 10a or downstream nozzles including nozzle 10b based on the position of pattern set 114 where the density difference at the boundary between the first pattern portion and the second pattern portion is the smallest.

[0124] Furthermore, in the correction process of variant example 6, instead of making a correction to increase the amount of ink droplets ejected from the downstream nozzles, a correction may be made to decrease the amount of ink droplets ejected from the upstream nozzles, or a correction may be made to increase the amount of ink droplets ejected from the downstream nozzles and decrease the amount of ink droplets ejected from the upstream nozzles.

[0125] Furthermore, in the correction process of variant example 6, instead of making a correction to increase the amount of ink droplets ejected from the upstream nozzles, a correction may be made to decrease the amount of ink droplets ejected from the downstream nozzles, or a correction may be made to increase the amount of ink droplets ejected from the upstream nozzles and decrease the amount of ink droplets ejected from the downstream nozzles.

[0126] In addition, in the above-described embodiment, when there is no variation in the amount of ink droplets ejected between the multiple nozzles 10, the first pattern portions 72A-72I and the second pattern portions 82A-82I are recorded so that the density of each portion within the pattern portion is constant for each of the first pattern portions 72A-72I and the second pattern portions 82A-82I, but this is not limited to the above.

[0127] In the seventh modification, when the printer 1 is started for the first time, the control unit 50 also performs processing according to the flow of Fig. 5. However, as shown in Fig. 15, in the seventh modification, the first pattern group 191 recorded in the first pattern group recording process of S103 is different from the first pattern group 71 in the above-mentioned embodiment. Also, the second pattern group 201 recorded in the second pattern group recording process of S105 is different from the second pattern group 81 in the above-mentioned embodiment.

[0128] First pattern group 191 is composed of a plurality of first pattern portions 192A-192I arranged adjacent to each other in the scanning direction. First pattern portions 192A-192I are rectangular fill-in patterns. In Modification 7, first pattern portion 192E located in the center in the scanning direction corresponds to the "reference first pattern portion" of the present invention. Also, first pattern portion 192I corresponds to the "first pattern portion at the outermost end on one side in the second direction" of the present invention. Also, first pattern portion 192A corresponds to the "first pattern portion at the outermost end on the other side in the second direction" of the present invention.

[0129] In addition, in variant example 7, in the first pattern group recording process, when there is no variation in the ink droplet ejection amount between the multiple nozzles 10 that constitute the nozzle row 9, the control unit 50 records the first pattern portion 192E so that the density is constant.

[0130] Furthermore, in the seventh modification, in the first pattern group recording process, when there is no variation in the amount of ink droplets discharged between the multiple nozzles 10 constituting the nozzle row 9, the control unit 50 records the first pattern portions 192A-192D to the left of the first pattern portion 192E so that the density becomes lighter from nozzle 10a to nozzle 10b in the transport direction. Furthermore, at this time, the control unit 50 records the first pattern portions 192A-192D so that the average density is lighter than the density of the first pattern portion 192E and the change in density along the transport direction becomes greater for the first pattern portion closer to the left end.

[0131] Furthermore, in the seventh modification, in the first pattern group recording process, when there is no variation in the amount of ink droplets discharged between the multiple nozzles 10 constituting the nozzle row 9, the control unit 50 records the first pattern portions 192F-192I to the right of the first pattern portion 192E so that the density becomes lighter in the transport direction from nozzle 10b to nozzle 10a. At this time, the control unit 50 records the first pattern portions 192F-192I so that the average density is lighter than the density of the first pattern portion 192E and the change in density along the transport direction becomes greater for the first pattern portion closer to the right end.

[0132] Second pattern group 201 is composed of multiple second pattern portions 202A-202I arranged adjacent to each other in the scanning direction. Second pattern portions 202A-202I are rectangular fill patterns. In Modification 7, first pattern portion 202E located in the center of the scanning direction corresponds to the "reference second pattern portion" of the present invention. Second pattern portion 202I corresponds to the "second pattern portion at the outermost end on one side in the second direction" of the present invention. Second pattern portion 202A corresponds to the "second pattern portion at the outermost end on the other side in the second direction" of the present invention.

[0133] In addition, in variant example 7, in the second pattern group recording process, when there is no variation in the ink droplet ejection amount between the multiple nozzles 10 that constitute the nozzle row 9, the control unit 50 records the second pattern portion 202E so that it has the same constant density as the first pattern portion 192E.

[0134] Furthermore, in the seventh modification, in the second pattern group recording process, when there is no variation in the amount of ink droplets discharged between the multiple nozzles 10 constituting the nozzle row 9, the control unit 50 causes the second pattern portions 202A-202D to the left of the second pattern portion 202E to be recorded so that the density becomes lighter in the transport direction from nozzle 10a to nozzle 10b. At this time, the control unit 50 also causes the second pattern portions 202A-202D to be recorded so that the average density is lighter than the density of the second pattern portion 202E and the change in density along the transport direction becomes greater for the second pattern portion closer to the left end.

[0135] Furthermore, in the seventh modification, in the second pattern group recording process, when there is no variation in the amount of ink droplets discharged between the multiple nozzles 10 constituting the nozzle row 9, the control unit 50 records the second pattern portions 202F-202I to the right of the second pattern portion 202E so that the density becomes lighter in the transport direction from nozzle 10b to nozzle 10a. At this time, the control unit 50 records the second pattern portions 202F-202I so that the average density is lighter than the density of the first pattern portion 202E and the change in density along the transport direction becomes greater for the second pattern portion closer to the right end.

[0136] In the seventh modification, the first pattern group 191 and the second pattern group 201 are printed as described above, so that the unevenness correction pattern 190 having the first pattern group 191 and the second pattern group 201 is printed.

[0137] In the seventh modification, the variation in the amount of ink droplets ejected from the multiple nozzles 10 can be reduced by correcting the amount of ink droplets ejected from the multiple nozzles 10 to the amount of ink droplets ejected when printing the pattern set 194 having the smallest density difference at the boundary between the first pattern group 191 and the second pattern group 201. In this case, it is possible to make density unevenness at the boundary between image portions printed in two consecutive printing passes less noticeable, and it is also possible to make density unevenness along the transport direction in the image portions printed in each printing pass less noticeable.

[0138] In the above embodiment, the first pattern group 71 has a plurality of first pattern portions 72A-72D to the left of the first pattern portion 72E, and a plurality of first pattern portions 72F-72I to the right of the first pattern portion 72E. Similarly, the second pattern group 81 has a plurality of second pattern portions 82A-82D to the left of the second pattern portion 82E, and a plurality of second pattern portions 82F-82I to the right of the second pattern portion 82E. However, this is not limited to this.

[0139] The number of first pattern portions to the left of the first pattern portion 72E in the first pattern group 71 may be only 1. In this case, the number of second pattern portions to the left of the second pattern portion 82E in the second pattern group 81 will also be only 1.

[0140] Furthermore, the number of first pattern portions to the right of first pattern portion 72E may be only one. In this case, the number of second pattern portions to the right of second pattern portion 82E in second pattern group 81 will also be only one.

[0141] In the above embodiment, the unevenness correction pattern is recorded in a state where the recording paper P is held between both the transport roller 6 and the transport roller 7, but this is not limited to the above. For example, at least one of the first pattern group and the second pattern group may be recorded in a state where the recording paper P is held between only one of the transport roller 6 and the transport roller 7.

[0142] In the above embodiment, the selection signal is input by having the user operate the operation unit 61 of the printer 1, but this is not limiting. For example, the selection signal may be input by having the user operate a PC or the like connected to the printer 1.

[0143] In the above embodiment, the initial introduction is performed by performing suction purging, but this is not limiting. For example, a pressure pump may be provided in the middle of the tube 15 connecting the subtank 3 and the ink cartridge 14. Alternatively, a pressure pump connected to the ink cartridge may be provided in the printer. Then, with the nozzles 10 covered with the caps 41, the pressure pump is driven to pressurize the ink in the inkjet head 4 and discharge the ink in the inkjet head 4 from the nozzles 10, so-called pressure purging, thereby performing the initial introduction. In this case, the pressure pump corresponds to the "purging means" of the present invention.

[0144] Furthermore, in purging, the initial introduction may be performed by both suction by the suction pump 42 and pressurization by the pressurization pump. In this case, the combination of the maintenance unit 8 and the pressurization pump corresponds to the "purging means" of the present invention.

[0145] In the above example, the unevenness correction pattern is recorded immediately after the initial introduction is completed, and the ejection amount of the nozzle 10 is corrected based on the recording result, but this is not limited to the above. For example, the unevenness correction pattern may be recorded at another timing, such as when the user operates the operation unit 61 to give an instruction, and the ejection amount of the nozzle 10 may be corrected based on the recording result.

[0146] In the above example, when ink droplets are ejected from multiple nozzles 10 constituting a nozzle row 9 using the same signal, the inkjet head 4 has the characteristic that the amount of ink droplets ejected increases or decreases from nozzle 10a to nozzle 10b in the transport direction. An unevenness correction pattern is recorded, and the amount of ink droplets ejected from the nozzles 10 is corrected based on the recording results, but this is not limited to the above.

[0147] In variant 8, when the inkjet head 4 is caused to eject ink droplets by driving the multiple nozzles 10 constituting the nozzle row 9 with the same signal due to the influence of manufacturing errors, etc., the inkjet head 4 has either a first characteristic as shown in Figures 4(a) and (b) or a second characteristic as shown in Figures 16(a) to (d).

[0148] The characteristic in FIG. 16(a) is that the amount of ink droplets ejected from the central nozzle 10 in the transport direction is the largest, and the amount of ink droplets ejected gradually decreases from the central nozzle 10 toward the nozzles 10a and 10b in the transport direction.

[0149] The characteristic in FIG. 16(b) is that the amount of ink droplets ejected from the central nozzle 10 in the transport direction is the smallest, and the amount of ink droplets ejected gradually increases from the central nozzle 10 toward the nozzles 10a and 10b in the transport direction.

[0150] The characteristic of Figure 16(c) is that the amount of ink droplets ejected from the nozzles 10 other than those at both ends of the nozzle row 9 in the transport direction is approximately the same, and the amount of ink droplets ejected from the nozzles 10 at both ends of the nozzle row 9 in the transport direction is less than the amount of ink droplets ejected from the nozzles 10 other than those at both ends in the transport direction.

[0151] The characteristic of Figure 16 (d) is that the amount of ink droplets ejected from nozzles 10 other than those at both ends of the nozzle row 9 in the transport direction is approximately the same, and the amount of ink droplets ejected from nozzles at both ends of the nozzle row 9 in the transport direction is greater than the amount of ink droplets ejected from nozzles 10 other than those at both ends of the nozzle row 9 in the transport direction.

[0152] In other words, the second characteristic shown in Figures 16(a) to (d) is a characteristic in which the amount of ink droplets ejected from the nozzle 10 positioned in the center of the nozzle row 9 in the transport direction is greater than the amount of ink droplets ejected from the nozzles 10 at both ends of the nozzle row 9 in the transport direction, including nozzles 10a and 10b, or is less than the amount of ink droplets ejected from the nozzles 10 at both ends of the nozzle row 9 in the transport direction, including nozzles 10a and 10b.

[0153] In the eighth modification, the control unit 50 is capable of receiving a characteristic signal indicating whether the inkjet head 4 has the first characteristic or the second characteristic. During the manufacture of the printer 1, for example, an operator inputs the characteristic signal by operating the operation unit 61 based on the results of testing the inkjet head 4. The control unit 50 receives the input characteristic signal, and stores information regarding whether the inkjet head 4 has the first characteristic or the second characteristic in the flash memory 54 based on the received characteristic signal.

[0154] In the eighth modification, when the printer 1 is started for the first time, the control unit 50 performs processing according to the flow of FIG.

[0155] More specifically, the control unit 50 executes an initial introduction process similar to S101 in the above-described embodiment (S301). Next, the control unit 50 determines whether the inkjet head 4 has the first characteristic based on the characteristic information stored in the flash memory 54 (S302).

[0156] If the inkjet head 4 has the first characteristic (S302: YES), a first process is executed (S303). The first process is similar to steps S102 to S111 in the above embodiment, and therefore a detailed description thereof will be omitted here.

[0157] If the inkjet head 4 does not have the first characteristic, that is, if the inkjet head 4 has the second characteristic (S302: NO), the second process is executed (S304).

[0158] In the second process, the control unit 50 performs the process according to the flow of FIG. 18. More specifically, the control unit 50 first executes the process of S401 to S409 similar to S102 to S110 of the above-mentioned embodiment. However, in the case of the modified example 8, as shown in FIG. 19, in the second pattern group recording process of S404, the second pattern group 81 is recorded, and a plurality of partition lines 131 that partition the second pattern portions 82A to 82I into a plurality of regions 133 in the transport direction and a plurality of selection symbols 132 that allow the user to select the region 133 partitioned by the partition lines 131 are recorded on the right side of the second pattern group 81. The unevenness correction pattern 70 shown in FIG. 19 is an example in the case where the inkjet head 4 has the characteristics shown in FIG. 16(a). In the modified example 8, the unevenness correction pattern 70 recorded by S401 to S404 of the first process or the second process corresponds to the "first unevenness correction pattern" of the present invention.

[0159] In S408, the control unit 50 causes the user to select the pattern set 74 (selection symbols 73 of "A" to "I") having the smallest density difference at the boundary between the first pattern portion and the second pattern portion, and also causes the display unit 60 to display a selection screen for selecting the region 133 (selection symbols 132 of "1" to "8") in which the density reaches the peak among the multiple regions 133 separated by the separation line 131 of the second pattern portion. The peak density means that the density is the highest or the lowest. Here, when the characteristics of the inkjet head 4 are as shown in Figs. 16(a) and 16(b), the control unit 50 causes the user to select one region 133. On the other hand, when the characteristics of the inkjet head 4 are as shown in Figs. 16(c) and 16(d), the control unit 50 causes the user to select multiple regions 133 arranged in succession. When the unevenness correction pattern 70 is as shown in Fig. 19, for example, the selection symbol 73 of "D" is selected, and the selection symbol 132 of "5" is selected.

[0160] When the user inputs a selection signal by selecting these selection symbols 73, 132, the control unit 50 receives the selection signal. In S409, it is determined whether or not the selection signal has been received.

[0161] When the selection signal is received (S409: YES), the control unit 50 executes a first correction process (S410). The first correction process is the same as the correction process of S111 in the above embodiment, so a detailed description thereof will be omitted here.

[0162] Next, the control unit 50 executes the same paper feed process as in S401 (S411), and then executes a third pattern group recording process (S412). In the third pattern group recording process, the control unit 50 executes a recording pass to record a third pattern group 141 as shown in FIG. 20(a) on the recording paper P.

[0163] The third pattern group 141 is composed of a plurality of third pattern portions 142A-142I arranged adjacent to each other in the scanning direction. The third pattern portions 142A-142I are rectangular fill-in patterns. In this embodiment, among the third pattern portions 142A-142I, the third pattern portion 142E located at the center in the scanning direction corresponds to the "reference third pattern portion" of the present invention. The third pattern portion 142I at the right end corresponds to the "third pattern portion at the outermost end on one side in the second direction" of the present invention. The third pattern portion 142A at the left end corresponds to the "third pattern portion at the outermost end on the other side in the second direction" of the present invention.

[0164] Furthermore, in the third pattern group recording process, the control unit 50 causes all of the nozzles 10 constituting the nozzle row 9 to eject ink droplets, thereby recording the third pattern portions 142A to 142I on the recording paper P.

[0165] Furthermore, in the third pattern group recording process, ink droplets are ejected from each nozzle 10 in a state in which the amount of ink droplets ejected from the upstream nozzles or the downstream nozzles has been corrected in the first correction process in S410.

[0166] In addition, in the third pattern group recording process, when the control unit 50 records the third pattern portions 142F-142I to the right of the third pattern portion 142E (farther from the third pattern portion 142A), the control unit 50 makes the density of the region 133 (vertex position) indicated by the selection signal received in S409 lighter than that of the third pattern portion 142E, and the closer to the right end the control unit 50 records the third pattern portion, the lighter the density of the above-mentioned region 133 (vertex position).

[0167] In addition, in the third pattern group recording process, when the control unit 50 records the third pattern portions 142A-142D to the left of the third pattern portion 142E (farther from the third pattern portion 142I), the control unit 50 makes the density of the region 133 (vertex position) indicated by the selection signal received in S409 darker than that of the third pattern portion 142E, and also makes the density of the region 133 (vertex position) darker as the control unit 50 records a third pattern portion closer to the left end.

[0168] Next, the control unit 50 executes the same transport process as in S405 (S413), and then executes a fourth pattern group recording process (S414).

[0169] In the fourth pattern group recording process, the control unit 50 performs a recording pass to record the fourth pattern group 151 as shown in Fig. 20(b) on the recording paper P. As a result, an unevenness correction pattern 140 (the "second unevenness correction pattern" of the present invention) having the third pattern group 141 and the fourth pattern group 151 is recorded on the recording paper P.

[0170] The fourth pattern group 151 is composed of a plurality of fourth pattern portions 152A-152I arranged adjacent to each other in the scanning direction. The fourth pattern portions 152A-152I are rectangular fill-in patterns. The fourth pattern portions 152A-152I are arranged adjacent to each other on the upstream side in the transport direction of the third pattern portions 142A-142I, respectively. As a result, the portions of the third pattern portions 142A-142I recorded by the nozzle 10a and the portions of the fourth pattern portions 152A-152I recorded by the nozzle 10b are adjacent to each other in the transport direction.

[0171] In the eighth modification, fourth pattern portion 152E corresponds to the "reference fourth pattern portion" of the present invention. Fourth pattern portion 152I at the right end corresponds to the "fourth pattern portion at the outermost end on one side in the second direction" of the present invention. Fourth pattern portion 152A at the left end corresponds to the "fourth pattern portion at the outermost end on the other side in the second direction" of the present invention.

[0172] Moreover, in the fourth pattern group recording process, the control unit 50 causes all of the nozzles 10 constituting the nozzle row 9 to eject ink droplets, thereby recording the fourth pattern portions 152A to 152I on the recording paper P.

[0173] Furthermore, in the fourth pattern group recording process, ink droplets are ejected from each nozzle 10 in a state in which the amount of ink droplets ejected from the upstream nozzles or the downstream nozzles has been corrected in the first correction process in S410.

[0174] Furthermore, in the fourth pattern group recording process, when the control unit 50 records the fourth pattern portions 152F-152I to the right of the fourth pattern portion 152E (farther from the fourth pattern portion 152A), the control unit 50 reduces the density of the region 133 (vertex position) indicated by the selection signal received in S409 compared to the fourth pattern portion 152E, and the closer to the right end the fourth pattern portion is recorded, the lighter the density of the above-mentioned region 133 (vertex position).

[0175] In addition, in the fourth pattern group recording process, when the control unit 50 records the fourth pattern portions 152A-152D to the left of the fourth pattern portion 152E (farther from the fourth pattern portion 152I), the control unit 50 increases the density of the region 133 (vertex position) indicated by the selection signal compared to the fourth pattern portion 152E, and also increases the density of the region 133 (vertex position) as the control unit 50 records a fourth pattern portion closer to the left end.

[0176] Next, the control unit 50 executes a conveying process similar to S106 in the above embodiment (S415), and then executes a selection symbol recording process similar to S107 in the above embodiment (S416), and records a plurality of selection symbols 143 for allowing the user to select a pattern set 144 of a third pattern portion and a fourth pattern portion aligned in the conveying direction, as shown in Fig. 20(c). Next, the control unit 50 executes a paper discharge process similar to S108 (S417).

[0177] Next, the control unit 50 causes the display unit 60 to display a selection screen for allowing the user to select the pattern set 144 having the most uniform density (S418). Then, the user operates the operation unit 61 to input a selection signal for selecting the pattern set 144, and the control unit 50 waits until it receives this selection signal (S419: NO).

[0178] Then, when the control unit 50 receives the selection signal (S419: YES), it executes the second correction process (S420). In the second correction process, when the selection signal indicates the pattern set 144 of the third pattern portion 142E and the fourth pattern portion 152E ("E" is selected), the control unit 50 does not perform further correction of the amount of ink droplets ejected from the nozzles 10.

[0179] Furthermore, in the second correction process, when the selection signal indicates a pattern set 144 to the left of the pattern sets 144 of the third pattern portion 142E and the fourth pattern portion 152E (one of "A" to "D" is selected), the control unit 50 performs a correction such that the amount of ink droplets ejected from the nozzles 10 used to record the vertex position is reduced when the pattern set 144 indicated by the selection signal is closer to the left end.

[0180] Furthermore, in the second correction process, when the selection signal indicates a pattern set 144 to the right of the pattern set 144 of the third pattern portion 142E and the fourth pattern portion 152E (one of "F" to "I" is selected), the control unit 50 performs a correction such that the amount of ink droplets ejected from the nozzle 10 used to record the vertex position is increased when the pattern set 144 indicated by the selection signal is the pattern set 114 closer to the right end.

[0181] In variant example 8, regardless of whether the inkjet head 4 has a first characteristic or a second characteristic as a characteristic related to the variation in the amount of ink droplets ejected among multiple nozzles 10 in a nozzle row 9, an unevenness correction pattern according to the characteristic is recorded, and the variation in the amount of ink droplets ejected among the nozzles 10 can be corrected based on the recording results.

[0182] Furthermore, the inkjet head 4 may have a characteristic that, as a characteristic of the variation in the amount of ink droplets ejected among the multiple nozzles 10, when the inkjet head 4 is driven by the same signal for the multiple nozzles 10, the amount of ink droplets ejected in the transport direction gradually decreases or increases from nozzle 10a to nozzle 10b. Therefore, in Modification 8, the above characteristic is defined as the first characteristic. When the inkjet head 4 has the first characteristic, the unevenness correction pattern 70 is recorded, and the amount of ink droplets ejected from the nozzles 10 is corrected based on the recording result.

[0183] Furthermore, the inkjet head 4 may have a characteristic that, as a characteristic of the variation in the amount of ink droplets discharged among the multiple nozzles 10, when the inkjet head 4 is driven by the same signal for the multiple nozzles 10, the amount of ink droplets discharged from the nozzle 10 located at the center of the multiple nozzles 10 in the transport direction is greater than the amount of droplets discharged from the nozzles 10a and 10b, or is less than the amount of droplets discharged from the nozzles 10a and 10b. Therefore, in the eighth modification, the above characteristic is defined as the second characteristic. When the inkjet head 4 has the second characteristic, the unevenness correction patterns 70 and 140 are recorded, and the amount of ink droplets discharged from the nozzles 10 is corrected based on the results of recording the unevenness correction patterns.

[0184] Moreover, the second process is not limited to that of Modification 8. In Modification 9, in the second process, the control unit 50 performs processing along the flow of FIG.

[0185] More specifically, in the second process of the ninth modified example, the control unit 50 first executes a paper feed process similar to S101 in the above-described embodiment (S501), and then executes a pattern recording process for apex detection (S502). In the pattern recording process for apex detection, the control unit 50 performs a recording pass to record a pattern 161 for apex detection and a plurality of selection symbols 162 as shown in FIG. 22(a) on the recording paper P.

[0186] The apex detection pattern 161 is a band-shaped pattern extending in the transport direction, and is recorded in a recording pass by driving the inkjet head 4 with the same drive signal to eject ink droplets for all nozzles 10 constituting the nozzle row 9. The multiple selection symbols 162 are intended to allow the user to select multiple areas 161a obtained by dividing the apex detection pattern 161 in the transport direction, and are recorded adjacent to each area 161a in the scanning direction.

[0187] Next, the control unit 50 executes the same paper discharge process as S109 in the above embodiment (S503). Next, the control unit 50 causes the display unit 60 to display a selection screen for allowing the user to select the region 161a (selection symbol 162 of "A" to "I") where the density reaches the peak (S504), and waits until the user operates the operation unit 61 to input a selection signal for selecting the region 161a (selection symbol 162), and the control unit 50 receives this selection signal (S505: NO).

[0188] Here, if the inkjet head 4 has characteristics as shown in Figures 16(a) and (b), the user is prompted to select one area 161a. On the other hand, if the inkjet head 4 has characteristics as shown in Figures 16(c) and (d), the user is prompted to select multiple areas 161a that are consecutively arranged.

[0189] It should be noted that the apex detection pattern 161 shown in Figure 22(a) is an example when the characteristics of the inkjet head 4 are as shown in Figure 16(a), and for example, an area 161a corresponding to the selection symbol 162 of "C" is selected.

[0190] When the control unit 50 receives the selection signal (S505: YES), the control unit 50 executes a paper feed process (S506), and then executes a correction amount determination pattern recording process (S507). In the correction amount determination pattern recording process, a correction amount determination pattern 170 and a plurality of selection symbols 175 as shown in Fig. 22(b) are recorded by repeating a recording pass and a transport operation. In the ninth modification, the apex detection pattern 161 and the correction amount determination pattern 170 correspond to the "second unevenness correction pattern" of the present invention.

[0191] The correction amount determination pattern 170 has three pattern groups 171 to 173. The pattern group 171 has a plurality of pattern portions 181 aligned in the scanning direction. Each of the plurality of pattern portions 181 is recorded by the nozzle 10 used to record the region 161a (the region 161a corresponding to the selection symbol 162 of "A" in FIG. 22(a)) on the most upstream side in the transport direction of the apex detection pattern 161. The density of each of the plurality of pattern portions 181 is the same as the density of the region 161a on the most upstream side in the transport direction of the apex detection pattern 161.

[0192] The pattern group 172 is adjacent to the pattern group 171 on the upstream side in the transport direction. The pattern group 172 has a plurality of pattern portions 182 arranged in the scanning direction. The plurality of pattern portions 182 are recorded by the nozzles 10 used for recording the region 161a (the region 161a corresponding to the selection symbol 162 of "I" in FIG. 22(a)) on the most downstream side in the transport direction of the apex detection pattern 161. The density of the pattern portion 182 located at the center in the scanning direction among the plurality of pattern portions 182 is the same as the density of the region 161a on the most downstream side in the transport direction of the apex detection pattern 161. The pattern portion 182 closer to the right end than this pattern portion 182 has a higher density, and the pattern portion 182 closer to the left end than this pattern portion 182 has a lower density.

[0193] The pattern group 173 is adjacent to the pattern group 171 on the downstream side in the transport direction. The pattern group 173 has a plurality of pattern portions 183 arranged in the scanning direction. Each of the plurality of pattern portions 183 is recorded by the nozzle 10 used for recording the region 161a indicated by the selection signal received in S504. Furthermore, among the plurality of pattern portions 183, the density of the pattern portion 183 located at the center in the scanning direction is the same as the density of the region 161a indicated by the selection signal received in S504. Furthermore, the pattern portions 183 closer to the right end than this pattern portion 183 have a higher density, and the pattern portions 183 closer to the left end than this pattern portion 183 have a lower density.

[0194] The multiple selection symbols 175 are intended to allow the user to select a row 174 of pattern portions 181, 182, and 183 aligned in the transport direction, and are arranged adjacent to each row 174 in the transport direction.

[0195] Next, the control unit 50 executes the paper discharge process (S508). Next, the control unit 50 causes the display unit 60 to display a selection screen for allowing the user to select the column 174 having the smallest density difference between the pattern portion 181 and the pattern portion 182 and the column 174 having the smallest density difference between the pattern portion 181 and the pattern portion 183 (S509), and waits until the user operates the operation unit 61 to input a selection signal for selecting these columns 174 (selection symbols 175), and the control unit 50 receives this selection signal (S510: NO).

[0196] 22(b) is an example when the apex detection pattern 161 is as shown in Fig. 22(a), and in this case, for example, column 174 corresponding to selection symbol 175 of "G" is selected as column 174 in which the density difference between pattern portion 181 and pattern portion 182 is the smallest. Also, column 174 corresponding to selection symbol 175 of "C" is selected as column 174 in which the density difference between pattern portion 181 and pattern portion 183 is the smallest.

[0197] When the control unit 50 receives the selection signal (S510: YES), the control unit 50 executes a correction process to correct the amount of ink droplets discharged from the nozzle 10 (S511). Here, in the ninth modification, information on the position in the transport direction at which the amount of ink droplets discharged reaches the peak in the nozzle row 9 can be obtained based on the selection signal received in S505. Also, information on the difference in the amount of ink droplets discharged between the nozzle 10a and the nozzle 10b can be obtained based on the selection signal received in S510 indicating the row 174 at which the density difference between the pattern portion 181 and the pattern portion 182 is the smallest. Also, information on the difference in the amount of ink droplets discharged between the nozzle 10a and the nozzle 10 at which the amount of ink droplets discharged reaches the peak can be obtained based on the selection signal received in S510 indicating the row 174 at which the density difference between the pattern portion 181 and the pattern portion 183 is the smallest. Then, in S510, the amount of ink droplets discharged from the nozzle 10 is corrected based on these pieces of information.

[0198] In addition, the second characteristics are not limited to those shown in Figures 16(a) to (d). If the inkjet head 4 has second characteristics different from those shown in Figures 16(a) to (d), a second unevenness correction pattern corresponding to the second characteristics may be recorded by the second process, and the amount of ink droplets ejected from the nozzles 10 may be corrected based on the recording result.

[0199] Moreover, the first characteristic is not limited to the one described above. Regardless of the characteristics of the first characteristic and the second characteristic, when the inkjet head 4 has the first characteristic, a first unevenness correction pattern corresponding to the first characteristic may be recorded, and the amount of ink droplets ejected from the nozzle 10 may be corrected based on the recording result, and when the inkjet head 4 has the second characteristic, a second unevenness correction pattern corresponding to the second characteristic may be recorded, and the amount of ink droplets ejected from the nozzle 10 may be corrected based on the recording result.

[0200] Even in this case, regardless of whether the inkjet head 4 has the first characteristic or the second characteristic as a characteristic related to the variation in the amount of ink droplets ejected among the multiple nozzles 10 in the nozzle row 9, an unevenness correction pattern according to the characteristic can be recorded, and the variation in the amount of ink droplets ejected among the nozzles 10 can be corrected based on the recording results.

[0201] In the above example, the inkjet head 4 and the recording paper P move relatively in the transport direction as the recording paper P is transported in the transport direction by the transport rollers 6, 7, but this is not limited to the above. For example, a moving mechanism ("relative movement means" of the present invention) that moves the carriage 2 carrying the inkjet head 4 in the transport direction may be provided, and the inkjet head 4 and the recording paper P may move relatively in the transport direction as the carriage 2 moves in the transport direction. Alternatively, the inkjet head 4 and the recording paper P may both move in the transport direction, causing the inkjet head 4 and the recording paper P to move relatively in the transport direction. In this case, the carriage 2 and the moving mechanism correspond to the "relative movement means" of the present invention.

[0202] In the above, an example has been described in which the present invention is applied to a printer equipped with a so-called serial head that ejects ink from multiple nozzles while moving in the scanning direction together with the carriage, but the present invention is not limited to this. For example, the present invention can also be applied to a printer equipped with a so-called line head that extends across the entire length of the recording paper P in the scanning direction.

[0203] In a line head, in addition to the multiple nozzles being arranged in a direction perpendicular to the transport direction of the recording paper, multiple nozzles may also be arranged in the transport direction, for example, to increase the recording speed. Even in such a case, in the same manner as described above, a non-uniformity correction pattern is recorded, and the amount of ink droplets ejected from the nozzles 10 is corrected based on the recording result, thereby reducing the variation in the amount of ink droplets ejected between multiple nozzles arranged in the transport direction.

[0204] In the above, an example of applying the present invention to a printer that ejects ink from a nozzle to perform recording on recording paper P has been described, but the present invention is not limited to this. The present invention can also be applied to printers that record images on recording media other than recording paper, such as T-shirts, sheets for outdoor advertising, cases for mobile terminals such as smartphones, cardboard, and resin members. The present invention can also be applied to liquid droplet ejection devices that eject liquids other than ink, such as liquid resins and metals. [Explanation of symbols]

[0205] 1. Printer 4 Inkjet head 8 Maintenance Unit 10 Nozzles 50 Control section 70 Unevenness correction pattern 71 First Pattern Group 72A~72I First pattern part 81 Second Pattern Group 82A~82I Second pattern part 100a First nozzle group 100b Second nozzle group 101 Unevenness correction pattern 102 First Pattern Group 103 Second Pattern Group 110 Unevenness correction pattern 111 First Pattern Group 112A~112I First pattern part 121 Second Pattern Group 122A~122I Second pattern part 140 Unevenness correction pattern 141 Third Pattern Group 142A~142I 3rd pattern part 151 Fourth Pattern Group 152A~152I 4th ​​pattern part 161 Vertex detection pattern 170 Correction amount determination pattern

Claims

1. a droplet ejection head having a nozzle row composed of a plurality of nozzles arranged in a first direction; a relative movement unit that moves the droplet ejection head and the ejection receiving medium relatively in the first direction; A control unit, The control unit is controlling the droplet ejection head and the relative movement means to record an unevenness correction pattern on an ejection receiving medium for correcting variations in the amount of droplets ejected among the plurality of nozzles; When the unevenness correction pattern is recorded, causing the droplet ejection head to eject droplets from at least a first nozzle at one outermost end of the nozzle row in the first direction, thereby recording a first pattern group which is a part of the unevenness correction pattern and is composed of a plurality of first pattern portions arranged in a second direction intersecting the first direction; Then, the relative movement means moves the droplet ejection head and the ejection receiving medium relatively a predetermined distance in the first direction, and then the droplet ejection head ejects droplets from at least a second nozzle at the other outermost end of the nozzle row in the first direction, thereby recording a second pattern group that is part of the unevenness correction pattern, is aligned in the second direction, and is composed of a plurality of second pattern portions in which portions recorded by the second nozzles are aligned adjacent to portions recorded by the first nozzles of the plurality of first pattern portions in the first direction, the first pattern group includes a reference first pattern portion located between one outermost first pattern portion and the other outermost first pattern portion in the second direction, the second pattern group is located between one outermost second pattern portion in the second direction and the other outermost second pattern portion in the second direction, and includes a reference second pattern portion adjacent to the reference first pattern portion in the first direction, When the first pattern group is printed, a density of the first pattern portion at the outermost end in the second direction is made lower than a density of the reference first pattern portion; a second pattern portion having a density lower than a density of the reference second pattern portion when the second pattern group is recorded;

2. The control unit is When recording the first pattern group, the droplet ejection head ejects droplets from a first nozzle group including the first nozzle and constituted by a part of the nozzles of the nozzle row that are continuously arranged in the first direction, The droplet ejection device according to claim 1, characterized in that, when recording the second pattern group, the droplet ejection head is caused to eject droplets from a second nozzle group composed of a portion of the nozzle row that includes the second nozzle and is arranged continuously in the first direction.

3. The first nozzle group includes: The first nozzle; a nozzle located closer to the first nozzle than a nozzle located at a center of the nozzle row in the first direction, The second nozzle group is The second nozzle; 3. The droplet ejection device according to claim 2, wherein the nozzle row is configured with a nozzle located closer to the second nozzle than a nozzle located at a center in the first direction in the nozzle row.

4. 3. The droplet ejection device according to claim 2, wherein the nozzle row includes at least one nozzle located between the first nozzle group and the second nozzle group in the first direction.

5. the first pattern group includes a plurality of the first pattern portions that are farther away from the other outermost first pattern portion in the second direction than the reference first pattern portion, the second pattern group includes a plurality of second pattern portions that are farther from the one outermost second pattern portion in the second direction than the reference second pattern portion, The control unit is when recording a plurality of the first pattern portions which are farther away from the outermost first pattern portion of the other side than the reference first pattern portion in the second direction, a density of the first pattern portion which is farther away from the outermost first pattern portion of the other side is made lighter; A droplet ejection device as described in any one of claims 1 to 4, characterized in that when recording a plurality of second pattern portions that are farther away from the one outermost second pattern portion in the second direction than the reference second pattern portion, the concentration of the second pattern portion that is farther away from the one outermost second pattern portion is reduced.

6. The control unit is when recording the first pattern portion that is farther from the other outermost first pattern portion than the reference first pattern portion in the second direction, a density of the first pattern portion is made lighter from the second nozzle toward the first nozzle in the first direction; when recording the first pattern portion farther from the one outermost first pattern portion than the reference first pattern portion in the second direction, a density of the first pattern portion is decreased from the first nozzle toward the second nozzle in the first direction; when recording the second pattern portion farther from the other outermost second pattern portion than the reference second pattern portion in the second direction, a density of the second pattern portion is made lighter from the second nozzle toward the first nozzle in the first direction; A droplet ejection device as described in claim 5, characterized in that when recording the second pattern portion that is farther from the one outermost second pattern portion in the second direction than the reference second pattern portion, the density of the second pattern portion is made thinner as it moves from the first nozzle to the second nozzle in the first direction.

7. The control unit is when recording a plurality of the first pattern portions which are farther away from the other outermost first pattern portion than the reference first pattern portion in the second direction, the density of the first pattern portion which is farther away from the other outermost first pattern portion is reduced by causing the droplet discharge head to discharge at least the first nozzle per unit area; The droplet ejection device described in claim 5 or 6, characterized in that when recording a plurality of second pattern portions that are farther away from the one outermost second pattern portion in the second direction than the reference second pattern portion, the concentration of the second pattern portion that is farther away from the one outermost second pattern portion is reduced by causing the droplet ejection head to reduce the ejection amount from at least the second nozzle per unit area.

8. The control unit is when recording a plurality of the first pattern portions which are farther away from the outermost first pattern portion of the other side than the reference first pattern portion in the second direction, and a plurality of the second pattern portions which are farther away from the outermost second pattern portion of the one side than the reference second pattern portion, causing the droplet discharge head to thin out some of the droplets discharged from the plurality of nozzles based on mask data; when recording a plurality of the first pattern portions which are farther away from the outermost first pattern portion of the other side than the reference first pattern portion in the second direction, the density of the first pattern portion which is farther away from the outermost first pattern portion of the other side is reduced by thinning out the ejection of droplets based on mask data having a high thinning rate which is a ratio at which the ejection of droplets is thinned out; The droplet ejection device according to claim 7, characterized in that when recording a plurality of second pattern portions that are farther away from the one outermost second pattern portion in the second direction than the reference second pattern portion, the density of the second pattern portion that is farther away from the one outermost second pattern portion is reduced by thinning out the ejection of droplets based on mask data with a higher thinning rate.

9. the droplet discharge head is configured to selectively discharge one of a plurality of types of droplets having different volumes from each of the plurality of nozzles; The control unit is when recording a plurality of the first pattern portions which are farther away from the outermost first pattern portion of the other side than the reference first pattern portion in the second direction, the concentration is reduced by discharging droplets from at least the first nozzles such that the ratio of droplets having a smaller volume among the plurality of types of droplets is higher for the first pattern portion which is farther away from the outermost first pattern portion of the other side, The droplet ejection device described in claim 7, characterized in that when recording a plurality of second pattern portions that are farther away from the one outermost second pattern portion in the second direction than the reference second pattern portion, the concentration is reduced by ejecting droplets from at least the second nozzle so that the ratio of droplets ejected having a smaller volume among the plurality of types of droplets is higher for the second pattern portion that is farther away from the one outermost second pattern portion.

10. The relative movement means is a first conveying roller that holds the ejection receiving medium and conveys it in the first direction; a second transport roller that is disposed apart from the first transport roller in the first direction and that sandwiches the ejection receiving medium and transports it in the first direction, the droplet ejection head is located between the first transport roller and the second transport roller in the first direction; The control unit is 10. The droplet ejection device according to claim 1, wherein the unevenness correction pattern is recorded in a state in which the ejection receiving medium is held between both the first transport roller and the second transport roller.

11. The control unit is acquiring information on an optimum density position, which is a position in the second direction of the first pattern portion and the second pattern portion adjacent to each other in the first direction at which a density difference is smallest, based on a recording result of the unevenness correction pattern; controlling the droplet ejection head and the relative movement means to record the unevenness correction pattern again based on the information on the optimum density position; When the unevenness correction pattern is to be recorded again, The first pattern portion located at the density optimum position in the previously recorded unevenness correction pattern is reset to a reference first pattern portion, and the second pattern portion located at the density optimum position is reset to a reference second pattern portion; a density difference between the reset reference first pattern portion and an adjacent first pattern portion, and a density difference between adjacent first pattern portions that are farther away from the other outermost first pattern portion than the reset reference first pattern portion, are made smaller than the density difference between the previously recorded unevenness correction pattern; A droplet ejection device as described in any one of claims 1 to 10, characterized in that the density difference between the reset reference second pattern portion and the adjacent second pattern portion, and the density difference between adjacent second pattern portions that are farther away from the one outermost second pattern portion than the reset reference second pattern portion, are made smaller than the unevenness correction pattern previously recorded.

12. The control unit is acquiring information on an optimum density position, which is a position in the second direction of the first pattern portion and the second pattern portion adjacent to each other in the first direction at which a density difference is smallest, based on a recording result of the unevenness correction pattern; when the density optimum position is farther from the other outermost first pattern portion and the other outermost second pattern portion than the reference first pattern portion and the reference second pattern portion in the second direction, at least one of a correction for decreasing the amount of droplets ejected from the first nozzle and a correction for increasing the amount of droplets ejected from the second nozzle is performed; A droplet ejection device as described in any one of claims 1 to 11, characterized in that when the optimum concentration position is farther from the first pattern portion at the outermost end of one of the first patterns and the second pattern portion at the outermost end of the other of the first pattern portion ... second pattern portion and the second pattern portion at the outermost end of the other of the second pattern portion and the second pattern portion at the outermost end of the other of the second pattern portion and the second pattern portion at the outermost end of the other of the second pattern portion and the second pattern portion at the outermost end of the other of the second pattern portion and the second pattern portion at the outermost end of the other of the second pattern portion and the second pattern portion at the outermost end of the other of the second pattern portion and the second pattern portion at the outermost end of the other of the second pattern portion and the second pattern portion at the outermost end of the other of the second pattern portion and the second pattern portion at the outermost end of the other of the

13. an input unit for allowing a user to input a signal relating to a recording result of the unevenness correction pattern, A droplet ejection device as described in any one of claims 1 to 12, characterized in that the control unit corrects the amount of droplets ejected from at least one of the first nozzle and the second nozzle based on the signal input from the input unit.

14. The control unit is the droplet ejection head is configured to be capable of receiving a characteristic signal indicating whether the droplet ejection head has a first characteristic or a second characteristic different from the first characteristic, as a characteristic relating to a variation in the ejection amount of droplets among the plurality of nozzles; When the received characteristic signal indicates that the droplet ejection head has the first characteristic, a first unevenness correction pattern which is the unevenness correction pattern is recorded; A droplet ejection device as described in any one of claims 1 to 13, characterized in that when the received characteristic signal indicates that the droplet ejection head has the second characteristic, a second unevenness correction pattern separate from the first unevenness correction pattern is recorded.

15. the first characteristic is a characteristic that, when the droplet ejection head is driven by the same signal for the plurality of nozzles, the ejection amount of droplets from the plurality of nozzles gradually decreases or gradually increases from the first nozzle toward the second nozzle; The droplet ejection device described in claim 14, characterized in that the second characteristic is a characteristic in which, when the droplet ejection head is driven by the same signal for the multiple nozzles, the amount of droplets ejected from a nozzle among the multiple nozzles that is positioned at the center in the first direction is greater than the amount of droplets ejected from the first nozzle and the second nozzle, or is less than the amount of droplets ejected from the first nozzle and the second nozzle.

16. The control unit is When recording the first pattern group, the droplet ejection head ejects droplets from a first nozzle group including the first nozzle and constituted by a part of the nozzles of the nozzle row that are continuously arranged in the first direction, When recording the second pattern group, the droplet ejection head ejects droplets from a second nozzle group including the second nozzles and constituted by a portion of the nozzles in the nozzle row that are continuously arranged in the first direction, When the received characteristic signal indicates that the droplet ejection head has the second characteristic, before recording the second unevenness correction pattern, the droplet ejection head and the relative movement means are controlled to record the first unevenness correction pattern; Information on an optimum density position, which is a position in the second direction of the first pattern portion and the second pattern portion adjacent to each other in the first direction at which the density difference is smallest, based on a recording result of the first unevenness correction pattern; and information on a vertex position, which is a position in the first direction of a portion where the density reaches a peak in the first pattern portion and the second pattern portion based on a recording result of the first unevenness correction pattern, is acquired; controlling the droplet ejection head and the relative movement means to record the second unevenness correction pattern based on the information on the density optimum position and the information on the apex position; When the second unevenness correction pattern is recorded, causing the droplet ejection head to eject droplets from the first nozzle group, thereby recording a third pattern group which is a part of the second unevenness correction pattern and is composed of a plurality of third pattern portions arranged in the second direction; Then, the relative movement means moves the droplet ejection head and the ejection receiving medium relatively a predetermined distance in the first direction, and then the droplet ejection head is caused to eject droplets from the second nozzle group, thereby recording a fourth pattern group which is part of the second unevenness correction pattern, is aligned in the second direction, and is composed of a plurality of fourth pattern portions in which portions recorded by the second nozzles are aligned adjacent to portions recorded by the first nozzles of the plurality of third pattern portions in the first direction, the third pattern group includes a reference third pattern portion located between one outermost third pattern portion and the other outermost third pattern portion in the second direction, the fourth pattern group includes a reference fourth pattern portion located between one outermost fourth pattern portion and the other outermost fourth pattern portion in the second direction, When the third pattern group and the fourth pattern group are recorded, when the density optimum position is farther from the other outermost first pattern portion and the other outermost second pattern portion than the reference first pattern portion and the reference second pattern portion in the second direction, at least one of a correction for decreasing the amount of droplets ejected from the first nozzle group and a correction for increasing the amount of droplets ejected from the second nozzle group is performed to record the third pattern portions and the fourth pattern portions; when the optimum density position is farther from the one outermost first pattern portion and the one outermost second pattern portion than the reference first pattern portion and the reference second pattern portion in the second direction, performing at least one of a correction for decreasing the amount of droplets ejected from the second nozzle group and a correction for increasing the amount of droplets ejected from the first nozzle group to record the third pattern portions and the fourth pattern portions; moreover, when recording the third pattern portion farther from the other outermost third pattern portion than the reference third pattern portion in the second direction, the density at the vertex position of the third pattern portion is made lighter as the third pattern portion is recorded farther from the other outermost third pattern portion, when recording the third pattern portion farther from the one outermost third pattern portion than the reference third pattern portion in the second direction, the density at the vertex position of the third pattern portion is made higher as the third pattern portion is recorded farther from the one outermost third pattern portion, when recording the fourth pattern portion farther from the other outermost fourth pattern portion than the reference fourth pattern portion in the second direction, the density at the vertex position of the fourth pattern portion is made lighter as the fourth pattern portion is recorded farther from the other outermost fourth pattern portion, The droplet ejection device according to claim 15, characterized in that when recording the fourth pattern portion farther from the one of the outermost fourth pattern portions in the second direction than the reference fourth pattern portion, the density at the vertex position of the fourth pattern portion is made higher the farther the fourth pattern portion is recorded from the one of the outermost fourth pattern portions.

17. a droplet ejection head having a nozzle row composed of a plurality of nozzles arranged in a first direction; a relative movement unit that moves the droplet ejection head and the ejection receiving medium relatively in the first direction; A control unit, The control unit is controlling the droplet ejection head and the relative movement means to record an unevenness correction pattern on an ejection receiving medium for correcting variations in the amount of droplets ejected among the plurality of nozzles; When the unevenness correction pattern is recorded, causing the droplet ejection head to eject droplets from at least a first nozzle at one outermost end of the nozzle row in the first direction, thereby recording a first pattern group which is a part of the unevenness correction pattern and is composed of a plurality of first pattern portions arranged in a second direction intersecting the first direction; Then, the relative movement means moves the droplet ejection head and the ejection receiving medium relatively a predetermined distance in the first direction, and then the droplet ejection head ejects droplets from at least a second nozzle at the other outermost end of the nozzle row in the first direction, thereby recording a second pattern group that is part of the unevenness correction pattern, is aligned in the second direction, and is composed of a plurality of second pattern portions in which portions recorded by the second nozzles are aligned adjacent to portions recorded by the first nozzles of the plurality of first pattern portions in the first direction, the first pattern group includes a reference first pattern portion located between one outermost first pattern portion and the other outermost first pattern portion in the second direction, the second pattern group is located between one outermost second pattern portion in the second direction and the other outermost second pattern portion in the second direction, and includes a reference second pattern portion adjacent to the reference first pattern portion in the first direction, When the first pattern group is printed, a density of the first pattern portion at the outermost end in the second direction is made darker than a density of the reference first pattern portion; a second pattern portion at the other outermost end in the second direction having a density higher than a density of the reference second pattern portion when the second pattern group is recorded;

18. a droplet ejection head having a plurality of nozzles arranged in a first direction; a relative movement unit that moves the droplet ejection head and the ejection receiving medium relatively in the first direction; A control unit, The control unit is controlling the droplet ejection head and the relative movement means to record, on the ejection receiving medium, an unevenness correction pattern for correcting variation in the amount of droplet ejection between the plurality of nozzles in the droplet ejection head; the droplet ejection head is configured to be capable of receiving a characteristic signal indicating whether the droplet ejection head has a first characteristic or a second characteristic different from the first characteristic, as a characteristic relating to a variation in the ejection amount of droplets among the plurality of nozzles; When the unevenness correction pattern is recorded on the ejection receiving medium, If the received characteristic signal indicates that the droplet ejection head has the first characteristic, controlling the droplet ejection head and the relative movement means to record, as the unevenness correction pattern, a first unevenness correction pattern for correcting unevenness in the droplet ejection amount between the plurality of nozzles in the droplet ejection head having the first characteristic on a recording medium; If the received characteristic signal indicates that the droplet ejection head has the second characteristic, A droplet ejection device characterized by controlling the droplet ejection head and the relative movement means to record a second unevenness correction pattern, separate from the first unevenness correction pattern, on a recording medium as the unevenness correction pattern, for correcting variation in the droplet ejection amount between the multiple nozzles in the droplet ejection head having the second characteristic.

19. a liquid tank connected to the droplet ejection head; a purge unit that performs purging to discharge liquid from within the droplet ejection head through the plurality of nozzles, When the droplet ejection device is manufactured, the droplet ejection head is filled with a storage liquid different from the liquid to be ejected from the plurality of nozzles; The control unit is When the droplet discharge device is used for the first time, the purging means is caused to perform the purging, thereby discharging the storage liquid from the droplet discharge head and performing an initial introduction of the liquid to be discharged from the nozzle from the liquid tank; 19. The droplet ejection device according to claim 1, wherein the non-uniformity correction pattern is recorded after the initial introduction is completed.

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