Recording device and method for acquiring position adjustment values ​​of the recording device

Abstract

To solve the problem that improvement in recording is desired so that even if an error which is not adjusted occurs between recording by preceding scanning and subsequent scanning, influence of the error can be removed as much as possible and necessary information can be obtained properly from recorded results by a plurality of times of scanning.SOLUTION: A recording device controls a recording head so that n-test patterns in which deviation amounts between different scanning can be obtained are recorded, in a main scanning direction, on a medium, where the n is three or more integers. One test pattern is formed from the plurality of patches that are recorded by a plurality of times of scanning and the n-test patterns are formed so that positional relations of the plurality of patches are different from each other, which are recorded in parallel in an order which is different from an order in which the positional relations of the plurality of patches change gradually, in the main scanning direction.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a recording device and recording Acquisition of device position adjustment values Regarding the method. [Background technology]

[0002] A technique is disclosed for adjusting the amount of media transported in the sub-scanning direction to eliminate the error between the dot landing position on the media due to scanning at the tip of the recording head and the dot landing position on the media due to subsequent scanning after the media has been transported.

[0003] As a related technology, a recording device has been disclosed that includes: a first recording means for recording multiple reference patterns on a recording medium in the main scanning direction; a second recording means for recording multiple adjustment patterns in the main scanning direction after the recording medium has been transported by a sub-scanning means, wherein the second recording means uses a nozzle corresponding to the area where the reference pattern is recorded or a nozzle in the vicinity of that nozzle, and uses different nozzles or combinations of nozzles for recording each of the multiple adjustment patterns, thereby recording multiple adjustment patterns that are gradually shifted in position relative to the reference pattern in the sub-scanning direction; and a calculation means for calculating the amount of recording medium transported by the sub-scanning means based on the density difference of the multiple patterns formed by the first and second patterns (see Patent Document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2006-272957 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] If errors other than the transport amount to be adjusted occur between the process of recording a pattern by the first scan and the process of recording a pattern by the second scan, it becomes impossible to accurately determine the transport amount from the pattern recording results, and appropriate adjustments cannot be made. In particular, skew, where the medium tilts with respect to the transport direction, can occur between the first scan and the second scan. When skew occurs in the medium, the degree of skew affects multiple patterns created by the first and second patterns in the aforementioned reference 1 differently depending on the position of each pattern, making it difficult to appropriately calculate the transport amount of the recording medium by evaluating the recording results of these multiple patterns. Note that errors other than the object to be adjusted that occur between the recording by the first scan and the recording by the second scan are not limited to skew in the medium.

[0006] Given this situation, improvements are needed to minimize the impact of errors other than those targeted for adjustment, even if errors occur between the records from the first scan and the records from the subsequent scan, so that the necessary information can be correctly obtained from the results recorded by multiple scans. [Means for solving the problem]

[0007] The recording device is A recording device comprising a recording head having a plurality of nozzles for discharging liquid into a medium, and a control unit for controlling the recording head, wherein recording is performed on the medium by scanning while moving the recording head along a predetermined main scanning direction and discharging liquid from the recording head, wherein the control unit controls the recording head to record n ​​test patterns on the medium in the main scanning direction, each test pattern being capable of obtaining the amount of deviation between different scans, when n is an integer of 3 or more, and one of the test patterns is 2 Recorded by the aforementioned scan 2 The n test patterns are formed by patches of the following: The two above Patch relative Positional relationship For each of the aforementioned test patterns They are formed differently, and in the main scanning direction, The two above Patch relative The data is recorded in an order different from the order in which the positional relationship gradually changes. The control unit, with the two patches referred to as the first patch and the second patch, obtains the density at the boundary between the first patch and the second patch for each test pattern, calculates an approximate straight line on a graph with the density at the boundary on the vertical axis and a position adjustment value corresponding to the relative positional relationship between the first patch and the second patch on the horizontal axis, and obtains the position adjustment value when the approximate straight line gives a density that is not at the boundary between the two patches. .

[0008] The method for obtaining the position adjustment value of the recording device is: A recording method for performing recording on a medium by causing a recording head having a plurality of nozzles for discharging liquid to a medium to move along a predetermined main scanning direction and causing the recording head to discharge liquid, Acquisition of device position adjustment values wherein, when n is an integer of 3 or more, a recording control step is provided for controlling the recording head to record n test patterns on the medium in the main scanning direction, and the test patterns can be obtained for a shift amount between different scans. In the recording control step, one of the test patterns is 2 formed by patches recorded by 2 the scans, and the n test patterns are The two above formed such that the relative positional relationship of the patches is For each of the aforementioned test patterns different, and in the main scanning direction, The two above the patches are relative recorded in an order different from the order in which the positional relationship of the patches gradually changes. The method for obtaining the position adjustment value includes the steps of: obtaining the density at the boundary between the first patch and the second patch for each test pattern; calculating an approximate straight line on a graph with the density at the boundary on the vertical axis and the position adjustment value corresponding to the relative positional relationship between the first patch and the second patch on the horizontal axis; and obtaining the position adjustment value when the approximate straight line gives a density that is not at the boundary between the two patches. .

Brief Description of the Drawings

[0009] [Figure 1] A block diagram simply showing the device configuration of the present embodiment. [Figure 2] A diagram simply showing the relationship between the recording head and the medium from a top view point. [Figure 3] A diagram for explaining conventional TP group recording and adjustment value acquisition on the premise of no skew. [Figure 4] A diagram for explaining conventional TP group recording and adjustment value acquisition on the premise of having skew. [Figure 5] A flowchart showing the processing executed by the control unit of the present embodiment. [Figure 6] A diagram for explaining TP group recording and adjustment value acquisition adopting an unsorted order. [Figure 7] A diagram for explaining a specific example of the first method. [Figure 8] FIG. 8A and FIG. 8B are diagrams each showing a part of a medium on which a TP group according to a modification example is recorded. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the figures. Note that the figures are merely illustrative examples for illustrating these embodiments. Because the figures are illustrative, the proportions, shapes, and shading may not be accurate, they may not be consistent with each other, and some parts may be omitted.

[0011] 1. Outline of the device configuration: Figure 1 shows a simplified configuration of the recording device 10 according to this embodiment. The recording method is performed by the recording device 10. The recording device 10 includes a control unit 11, a display unit 13, an operation reception unit 14, a storage unit 15, a communication IF 16, a transport unit 17, a carriage 18, a recording head 19, etc. IF stands for interface. The control unit 11 is composed of one or more ICs having a CPU 11a as a processor, ROM 11b, RAM 11c, etc., and other non-volatile memory, etc.

[0012] In the control unit 11, the processor, i.e., the CPU 11a, performs calculations according to the program 12 stored in the ROM 11b or other memory, using the RAM 11c or the like as a work area, thereby realizing various functions such as the TP recording control unit 12a and the adjustment value calculation unit 12b. TP stands for test pattern. Program 12 corresponds to the recording control program. The TP recording control unit 12a and the adjustment value calculation unit 12b are only a part of the functions that the recording device 10 realizes according to program 12. The processor is not limited to a single CPU; it may be configured to perform processing using multiple CPUs or hardware circuits such as ASICs, or it may be configured in which the CPU and hardware circuits cooperate to perform processing.

[0013] The display unit 13 is a means for displaying visual information and is composed of, for example, a liquid crystal display or an organic EL display. The display unit 13 may also include a display and a drive circuit for driving the display. The operation reception unit 14 is a means for receiving operations and inputs from the user, and can be implemented, for example, by physical buttons, a touch panel, a mouse, or a keyboard. The display unit 13 and the operation reception unit 14 together may be called the operation panel of the recording device 10. The operation reception unit 14 as a touch panel is implemented as a function of the display unit 13. Therefore, the display unit 13 may be understood as having a configuration that includes the operation reception unit 14.

[0014] The storage unit 15 is, for example, a hard disk drive, a solid-state drive, or other memory-based storage means. The storage unit 15 may be considered as a part of the memory possessed by the control unit 11. Alternatively, the storage unit 15 may be considered as a part of the control unit 11.

[0015] The communication IF 16 is a general term for one or more interfaces that enable the recording device 10 to communicate with an external device via wired or wireless connection in accordance with a predetermined communication protocol, including a known communication standard. The communication IF 16 corresponds to the communication unit. The external device is, for example, a communication device such as a personal computer (PC), server, smartphone, or tablet terminal. In the example in Figure 1, the recording device 10 is connected to the reading device 1 via the communication IF 16. The number of external devices that the recording device 10 can connect to for communication is not limited to one. The reading device 1 is a means capable of reading the medium 30 after it has been recorded by the recording device 10, and may be a scanner or a colorimeter. The reading device 1 may also be part of the recording device 10.

[0016] The transport unit 17 is a means for transporting the medium 30 along a predetermined transport path under the control of the control unit 11. The transport unit 17 includes, for example, rollers that rotate to transport the medium 30, and a motor as a power source for rotation. Alternatively, the transport unit 17 may be a mechanism that transports the medium 30 by loading it onto a drum, belt, or pallet driven by a motor. The medium 30 is, for example, paper, but can be any medium that can be used for liquid recording, and may be made of materials other than paper, such as film or fabric.

[0017] The carriage 18 is a moving means that, under the control of the control unit 11, moves back and forth along a predetermined main scanning direction using the power of a carriage motor (not shown). The carriage 18 is mounted on a recording head 19. The recording head 19 is a means of recording by ejecting liquid onto the medium 30 using an inkjet method under the control of the control unit 11. The droplets ejected by the recording head 19 are called dots. The liquid is mainly ink.

[0018] The recording head 19 is capable of ejecting inks of various colors, such as cyan (C), magenta (M), yellow (Y), and black (K). Of course, the recording head 19 may also be capable of ejecting inks of colors other than CMYK, or liquids other than ink. The movement of the carriage 18 and the movement of the recording head 19 are synonymous. The carriage 18 and the recording head 19 may be considered together as the recording head, or they may be called the recording unit.

[0019] The recording device 10 is a single printer in which its components are integrated into one unit. Alternatively, the recording device 10 may be a recording system realized by the communication between multiple devices or equipment. The recording system may include, for example, an information processing device that mainly performs the role of a control unit 11, and a printer that performs recording under the control of the information processing device, including a transport unit 17, a carriage 18, and a recording head 19. In this case, the information processing device can be understood as a recording control device or an image processing device, etc. The display unit 13, the operation reception unit 14, and the storage unit 15 may be part of the information processing device or printer, or peripheral devices connected to the information processing device or printer.

[0020] Figure 2 shows a simplified view of the relationship between the recording head 19 and the medium 30 from above. The recording head 19 has multiple nozzles 20 capable of dispensing liquid. Each white circle in Figure 2 represents an individual nozzle 20. The main scanning direction D1 and the sub-scanning direction D2 intersect. Here, the intersection is orthogonal or nearly orthogonal. The direction D2 that intersects the main scanning direction D1 is also called the transport direction D2.

[0021] The recording head 19 has nozzle groups for each type of liquid. In Figure 2, nozzle groups 21C, 21M, 21Y, and 21K are shown in a very simplified manner. In each of the nozzle groups 21C, 21M, 21Y, and 21K, there are multiple nozzles 20 arranged in a row, with a nozzle pitch that is constant or nearly constant, which is the distance between the nozzles 20 in the sub-scanning direction D2. The transport unit 17 transports the medium 30 from upstream to downstream in the sub-scanning direction D2, as indicated by the arrow in the sub-scanning direction D2. The upstream and downstream of the sub-scanning direction D2, i.e., the transport direction D2, are simply referred to as upstream and downstream.

[0022] Nozzle group 21C is a nozzle group consisting of multiple nozzles 20 that eject C ink. Similarly, nozzle group 21M is a nozzle group consisting of multiple nozzles 20 that eject M ink, nozzle group 21Y is a nozzle group consisting of multiple nozzles 20 that eject Y ink, and nozzle group 21K is a nozzle group consisting of multiple nozzles 20 that eject K ink. Multiple nozzle groups 21C, 21M, 21Y, and 21K are arranged along the main scanning direction D1 and are in the same position in the sub-scanning direction D2. In Figure 2, the nozzle arrangement direction of multiple nozzles 20 constituting the same nozzle group is shown as parallel to the sub-scanning direction D2, but the nozzle arrangement direction may intersect the sub-scanning direction D2 at an angle. The length of the nozzle group in the sub-scanning direction D2 is called the nozzle group length.

[0023] The control unit 11 causes the recording head 19 to eject ink based on recording data that represents the image to be recorded. As is well known, the recording head 19 is equipped with a drive element for each nozzle 20, and the application of a drive signal to the drive element of each nozzle 20 is controlled according to the recording data, so that each nozzle 20 ejects or does not eject the corresponding ink dot, and the image represented by the recording data is recorded on the medium 30. The recording data is data that defines whether to eject a dot or not to eject a dot for each pixel and for each ink color such as CMYK. Ejecting a dot is also called dot on, and not ejecting a dot is also called dot off.

[0024] The ink ejection by the recording head 9 accompanying the movement of the recording head 19 along the main scanning direction D1 by the carriage 18 is called "scanning" or "passing." The transport of a predetermined distance downstream by the transport unit 17 between passes is called "paper feeding." The control unit 11 records a two-dimensional image on the medium 30 by alternately repeating passes and paper feeding.

[0025] Movement from one side to the other along the main scanning direction D1 is called forward movement, and movement from the other side to the first side is called return movement. Furthermore, the path created by forward movement is called the forward path, and the path created by return movement is called the return path. Recording using both the forward and return paths is bidirectional recording, while recording using only one of the forward or return paths is unidirectional recording. In this embodiment, bidirectional recording is generally employed, but unidirectional recording may also be used.

[0026] The carriage 18, together with the recording head 19, may be a means of movement capable of reciprocating not only along the main scanning direction D1 but also along the sub-scanning direction D2. In other words, the recording head 19 may record a two-dimensional image on the medium 30 by moving a predetermined distance upstream between paths, which serves as a substitute for paper feeding. In this case, the transport unit 17 transports the medium 30 along the main scanning direction D1 rather than the sub-scanning direction D2. In other words, the transport unit 17 intermittently transports the medium 30 along the main scanning direction D1, and the recording head 19 may move along the main scanning direction D1 or sub-scanning direction D2 relative to the temporarily stopped medium 30 to record an image.

[0027] A recording method in which the recording head 19 moves along the main scanning direction D1 to execute a path, and the medium 30 is fed in the sub-scanning direction D2 between paths, as explained with reference to Figure 2, is called a serial method. On the other hand, a recording method in which the recording head 19 moves along the main scanning direction D1 to execute a path, and moves along the sub-scanning direction D2 instead of feeding paper between paths, is called a lateral method. The following explanation will continue assuming the serial method, but of course, the explanation may be interpreted as substituting the lateral method.

[0028] 2. Description of the assignment: The problems assumed by this embodiment will be specifically explained with reference to Figures 3 and 4. Figures 3 and 4 represent conventional examples. The upper part of Figure 3 shows a portion of the medium 30 on which the TP group 40 has been recorded by the printer. The TP group 40 contains n TPs 40a, 40b, 40c, 40d, and 40e. In this embodiment, n is an integer of 3 or more. In the example in Figure 3, n=5. As can be seen from Figure 3, the TPs 40a, 40b, 40c, 40d, and 40e of the TP group 40 are recorded in a line along the main scanning direction D1. In addition, each of the TPs 40a, 40b, 40c, 40d, and 40e is formed by a first patch 41 on the downstream side and a second patch 42 on the upstream side. In Figure 3, the reference numerals 41 and 42 are omitted for TPs 40a, 40b, 40d, and 40e other than TP40c. The first patch 41 and the second patch 42 have the same or nearly the same shape. In the following, "right" and "left" will simply refer to the perspective from upstream to downstream.

[0029] Multiple patches 41 and 42 forming a single TP are each recorded by different passes. That is, TPs 40a, 40b, 40c, 40d, and 40e are each recorded by two passes. Furthermore, TPs 40a, 40b, 40c, 40d, and 40e are formed such that their positional relationship with the first patch 41 and the second patch 42 is different from each other. In Figure 3, -2α, -α, 0, +α, and +2α are positional adjustment values ​​between the first patch 41 and the second patch 42 for each of TPs 40a, 40b, 40c, 40d, and 40e. α is a numerical value representing a predetermined distance.

[0030] Of TP40a, 40b, 40c, 40d, and 40e, the position adjustment value of TP40c, which is located in the center, is 0. This means that the positions of the first patch 41 and the second patch 42 have not been adjusted. In other words, TP40c, which has not adjusted the positions of the first patch 41 and the second patch 42, records the second patch 42 in the next pass after the first patch 41 has been recorded, following a paper feed according to the "standard feed amount," which is a predetermined amount of paper for one pass.

[0031] For simplicity, the lengths of the first patch 41 and the second patch 42 in the sub-scanning direction D2 are assumed to correspond to the nozzle group length. In other words, the first patch 41 and the second patch 42 are band images recorded in one pass of the recording head 19. The reference feed amount is a distance shorter than the nozzle group length by a predetermined number of nozzles. Therefore, after the recording head 19 records the first patch 41 in one pass, the transport unit 17 performs one paper feed of the reference feed amount, and the recording head 19 records the second patch 42 in the next pass, if there is no error in the paper feed, the upstream end of the first patch 41 and the downstream end of the second patch 42 will slightly overlap. The reference feed amount is set to be a distance shorter than the nozzle group length by a predetermined number of nozzles so that no gaps occur in the sub-scanning direction D2 between images recorded in each consecutive pass.

[0032] If the overlapping area between the upstream end of the first patch 41 and the downstream end of the second patch 42 becomes excessively large, the density of the overlapping area increases, making it easier to see as dark, streaky unevenness. On the other hand, if the overlapping area between the first patch 41 and the second patch 42 is too small, or if there is no overlap and a gap is created, the density between the first patch 41 and the second patch 42 decreases, making it easier to see as light, streaky unevenness. Hereafter, streaky unevenness that is darker than the patch color will be referred to as "black streaks," and streaky unevenness that is lighter than the patch color will be referred to as "white streaks."

[0033] In Figure 3, the position adjustment value for TP40b, recorded to the left of TP40c, is -α. This means that after the pass in which the first patch 41 was recorded, the paper was fed according to the instruction "reference feed amount -α", and in the next pass the second patch 42 was recorded, forming TP40b. In other words, TP40b has a greater overlap area and is more prone to black streaks than TP40c because the distance between the first patch 41 and the second patch 42 in the sub-scanning direction D2 is α closer. The position adjustment value for TP40a, recorded to the left of TP40b, is -2α. This means that after the pass in which the first patch 41 was recorded, the paper was fed according to the instruction "reference feed amount -2α", and in the next pass the second patch 42 was recorded, forming TP40a. Therefore, TP40a has a closer distance between the first patch 41 and the second patch 42 in the sub-scanning direction D2 than TP40b.

[0034] In Figure 3, the position adjustment value for TP40d, recorded to the right of TP40c, is +α. This means that after the pass in which the first patch 41 was recorded, the paper was fed according to the instruction "reference feed amount + α", and in the next pass the second patch 42 was recorded, forming TP40d. Compared to TP40c, TP40d has a greater distance of α between the first patch 41 and the second patch 42 in the sub-scanning direction D2, resulting in less overlap and a higher likelihood of white streaks. The position adjustment value for TP40e, recorded to the right of TP40d, is +2α. This means that after the pass in which the first patch 41 was recorded, the paper was fed according to the instruction "reference feed amount + 2α", and in the next pass the second patch 42 was recorded, forming TP40e. Therefore, TP40e has a greater distance between the first patch 41 and the second patch 42 in the sub-scanning direction D2 than TP40d.

[0035] The positional relationship between the first patch 41 and the second patch 42 of TP40a, 40b, 40c, 40d, and 40e changes gradually according to their arrangement in the main scanning direction D1. Thus, in the conventional TP group 40, n TP40a, 40b, 40c, 40d, and 40e are recorded on the medium 30 in an order in which the positional relationship between patches 41 and 42 gradually changes along the main scanning direction D1.

[0036] Figure 3 shows an example where TP40c shows no black or white streaks, TP40a and TP40b to the left of TP40c show black streaks, and TP40d and TP40e to the right of TP40c show white streaks. Also, the black streaks on TP40a on the far left are denser than those on TP40b, and the white streaks on TP40e on the far right are denser than those on TP40d. However, the transport accuracy of the media 30 differs from one printer to another. Therefore, even with TP40c, where the position adjustment value is 0, it is natural to expect that black or white streaks will appear in the recording result if there is an error in the paper feed. Furthermore, depending on the transport accuracy, it is possible, for example, that white streaks may appear on TP40c and almost no white or black streaks may appear on TP40b, or conversely, that black streaks may appear on TP40c and almost no white or black streaks may appear on TP40d.

[0037] The lower section of Figure 3 shows the muscle concentrations obtained from the readings of the TP group 40 recorded on the medium 30. In the lower section of Figure 3, the muscle concentrations for each position adjustment value of -2α, -α, 0, +α, +2α, i.e., each TP 40a, 40b, 40c, 40d, 40e, are plotted as black circles on a graph with muscle concentration on the vertical axis and position adjustment value on the horizontal axis. Muscle concentration is the brightness at the boundary between the first patch 41 and the second patch 42 for each TP. Muscle concentration can also be understood as the difference between the patch concentration in the medium 30 and the concentration at the boundary. Muscle concentration D0 is the ideal value of muscle concentration, referring to a state where there is no difference from the patch concentration, that is, a state where neither black nor white muscle is virtually visible. In the graph, muscle concentrations below muscle concentration D0, i.e., on the high concentration side, correspond to black muscle, and muscle concentrations above muscle concentration D0, i.e., on the low concentration side, correspond to white muscle. Such muscle density can be said to represent the amount of displacement between the first patch 41 and the second patch 42 in the sub-scanning direction D2. Therefore, TP40a, 40b, 40c, 40d, and 40e each correspond to test patterns that can acquire the amount of displacement between different scans.

[0038] The processor, having acquired muscle concentrations for each TP40a, 40b, 40c, 40d, and 40e, calculates an approximate straight line of these muscle concentrations. In the lower part of Figure 3, the approximate straight line F1 is calculated from the muscle concentrations for each TP40a, 40b, 40c, 40d, and 40e using the least squares method. The processor obtains -β in Figure 3 as the position adjustment value when the approximate straight line F1 gives muscle concentration D0. Subsequently, when recording by the printer, the processor adopts the position adjustment value -β and instructs the transport unit to feed "reference feed amount -β" as the amount of paper fed in one pass. This results in good recording quality in which no black or white streaks occur at the seams of each band image recorded on the medium 30 in each pass.

[0039] However, the explanation regarding Figure 3 assumes that no skew occurs in the paper feed between the path for recording the first patch 41 and the path for recording the second patch 42. Figure 4, like Figure 3, shows the medium 30 on which the TP group 40, consisting of TP40a, 40b, 40c, 40d, and 40e, is recorded in the upper part of the figure, and the muscle concentrations for each position adjustment value of -2α, -α, 0, +α, and +2α, obtained from the readings of TP40a, 40b, 40c, 40d, and 40e, are shown in the lower part of the figure. The interpretation of Figure 4 is the same as that of Figure 3.

[0040] In the lower part of Figure 4, the processor that acquired the muscle concentrations for each TP40a, 40b, 40c, 40d, and 40e shows the approximate straight line F2 calculated using the least squares method from these muscle concentrations. Also in the lower part of Figure 4, the approximate straight line F1 shown in Figure 3 is shown as a dashed line for reference. Furthermore, in the upper part of Figure 4, a dashed line simply indicates that skew occurred in the medium 30 during paper feeding between the path for recording the first patch 41 and the path for recording the second patch 42. This dashed line indicates the orientation of the downstream end of the medium 30.

[0041] When such skew occurs, among TP40a, 40b, 40c, 40d, and 40e, TP40a and TP40b, which are recorded on the left side of the medium 30, will have a positional relationship between the first patch 41 and the second patch 42 in the sub-scanning direction D2 that is even closer than the distance corresponding to the feed amount adjusted by -2α or -α as described above. On the other hand, TP40d and TP40e, which are recorded on the right side of the medium 30, will have a positional relationship between the first patch 41 and the second patch 42 in the sub-scanning direction D2 that is even wider than the distance corresponding to the feed amount adjusted by +α or +2α as described above. Furthermore, TP40a at the left end and TP40e at the right end will be more strongly affected by the skew.

[0042] As a result, the muscle density at each TP40a, 40b, 40c, 40d, and 40e is affected by the skew at each TP position, resulting in different values ​​compared to the case without skew. As shown in the lower part of Figure 4, an approximate line F2 different from the approximate line F1 is calculated. Therefore, the position adjustment value -γ that gives muscle density D0, obtained from the approximate line F2, is also different from the position adjustment value -β mentioned above. In other words, conventionally, the position adjustment value obtained from the approximate line differs depending on whether or not skew occurs in the medium 30. When skew occurs in the medium 30, the position adjustment value -γ obtained is affected by skew, making it impossible to properly adjust the paper feed amount, which is the original adjustment target, during subsequent recording.

[0043] 3. From recording TP data to obtaining adjustment values: Figure 5 shows a flowchart illustrating the process performed by the control unit 11 according to program 12, from recording the TP group to obtaining the adjustment value. Step S100 in this flowchart corresponds to the recording method in this embodiment. Figure 6, like Figures 3 and 4, shows the medium 30 on which a group of TPs 43 consisting of n TPs 40a, 40b, 40c, 40d, and 40e were recorded in the upper section of the figure, and the muscle concentrations for each position adjustment value of -2α, -α, 0, +α, and +2α obtained from the readings of TPs 40a, 40b, 40c, 40d, and 40e are shown in the lower section of the figure. The interpretation of Figure 6 is the same as that of Figures 3 and 4. Regarding the explanation of Figures 5 and 6, content common to the explanation of Figures 3 and 4 will be omitted as appropriate.

[0044] In step S100, the TP recording control unit 12a of the control unit 11 starts controlling the transport unit 17, carriage 18, and recording head 19, and causes the recording head 19 to eject ink based on the recording data representing the TP group 43 to record the TP group 43 onto the medium 30. As shown in Figure 6, the TP group 43 is arranged from left to right along the main scanning direction D1 in the order of TP40a, 40e, 40d, 40c, and 40b. The position adjustment values ​​for TP40a, 40e, 40d, 40c, and 40b are -2α, +2α, +α, 0, and -α, respectively, as described above. In other words, according to step S100, n TP40a, 40b, 40c, 40d, and 40e are arranged along the main scanning direction D1 in an order different from the order in which the positional relationship of patches 41 and 42 gradually changes, and are recorded on the medium 30. In the following text, we will refer to an arrangement of patches 41 and 42 in a different order from the order in which their relative positions gradually change as an "arrangement in no particular order."

[0045] This section provides additional information on the recording method for TP group 43 in step S100. The control unit 11 controls the recording head 19 to record a first patch 41 corresponding to each of the n TP40a, 40e, 40d, 40c, and 40b in a first pass, and to record a second patch 42 corresponding to each of the n TP40a, 40e, 40d, 40c, and 40b in a second pass, with each second patch 42 being recorded at a different position relative to the first patch 41. In other words, the control unit 11 records all of the first patch 41 for each of the TP40a, 40e, 40d, 40c, and 40b in a single pass using the recording head 19. Then, in a second pass that follows the pass in which the first patch 41 for each of the TP40a, 40e, 40d, 40c, and 40b was recorded, it records the second patch 42 for each of the TP40a, 40e, 40d, 40c, and 40b.

[0046] The method for recording the second patch 42 for each of TP40a, 40e, 40d, 40c, and 40b can be divided into two methods: a first method in which each second patch 42 is recorded in a single common pass, and a second method in which each second patch 42 is recorded in a different pass. Either the first or second method may be adopted.

[0047] According to the first method, the control unit 11 makes the positional relationship of patches 41 and 42 different for each TP by making the range of the nozzle 20 used for recording patches in the transport direction D2 different for each TP. Figure 7 is a diagram illustrating a specific example of the first method, and shows a magnified view of the nozzle group and a portion of the medium 30. In Figure 7, the nozzle group 21C is shown as the nozzle group. Of course, TP may be recorded with inks other than C ink. In Figure 7, the nozzle group 21C is simply shown as a long rectangle in the sub-scanning direction D2.

[0048] In Figure 7, due to space limitations, only TP40a and 40e are partially shown from TP40a, 40e, 40d, 40c, and 40b included in TP group 43. Also, in Figure 7, for the sake of clarity, the first patch 41 and the second patch 42, which form a single TP, are shown shifted in the main scanning direction D1. In reality, the first patch 41 and the second patch 42 that form a single TP are recorded at the same position in the main scanning direction D1.

[0049] The symbols P1 and P2 appended in parentheses to the nozzle group 21C represent the first pass P1 and the second pass P2. In other words, the relative positional relationship between the nozzle group 21C and the medium 30 in the sub-scanning direction D2 changes between the execution of the first pass P1 and the execution of the second pass P2 due to the paper feed between passes P1 and P2.

[0050] The control unit 11 records the first patches 41 of TP40a, 40e, 40d, 40c, and 40b in the first pass P1 of the recording head 19, at intervals along the main scanning direction D1. For paper feeding after the first pass P1, the control unit 11 instructs the transport unit 17 to set a "reference feed amount - 2α" to match the position adjustment value = -2α of TP40a, which brings the second patch 42 closest to the first patch 41, and then executes paper feeding of the instructed amount. Then, in the second pass P2 for recording the second patches 42 of TP40a, 40e, 40d, 40c, and 40b, the control unit 11 records the second patch 42 of TP40a by ejecting ink using the entire nozzle group 21C, including the downstream nozzle 20.

[0051] On the other hand, for recording the second patch 42 for each of TP40e, 40d, 40c, and 40b, the control unit 11 sets different unused nozzle ranges for each of TP40e, 40d, 40c, and 40b in the downstream range of the nozzle group 21C, including the most downstream nozzle 20, according to the position adjustment values ​​for each of TP40e, 40d, 40c, and 40b, such as +2α, +α, 0, and -α. Then, within the same second pass P2, the second patch 42 for each of TP40e, 40d, 40c, and 40b can be recorded by ejecting ink using each nozzle 20 in the non-unused range, which differs for each of TP40e, 40d, 40c, and 40b.

[0052] For example, the second patch 42 of TP40e with a position adjustment value of +2α needs to have its downstream end shifted upstream by a distance equivalent to 4 × α compared to the downstream end of the second patch 42 of TP40a. Therefore, during the period in the second pass P2 when the second patch 42 of TP40e is recorded, the control unit 11 sets the unused nozzle range equivalent to 4 × α in the sub-scanning direction D2 to the downstream range of the nozzle group 21C, which includes the furthest downstream nozzle 20. In Figure 7, the unused nozzle range during the period in the second pass P2 when the second patch 42 of TP40e is recorded is illustrated in gray. With this configuration, it is possible to record each second patch 42 with a different positional relationship to the corresponding first patch 41 within the same second pass P2.

[0053] According to the second method, the control unit 11 makes the transport distance that the transport unit 17 performs between passes for recording each patch different for each TP, thereby making the positional relationship of patches 41 and 42 different for each TP. In other words, after the first pass in which the first patch 41 of each TP 40a, 40e, 40d, 40c, and 40b is recorded together, the control unit 11 controls the transport unit 17, carriage 18, and recording head 19 to record the second patch 42 of each TP 40a, 40e, 40d, 40c, and 40b, and repeatedly executes paper feeding, the second pass, and backfeed. Backfeed is the transport of the medium 30 from downstream to upstream and is necessary to record the second patch 42 of the next TP after the second pass in which the second patch 42 of one TP has been recorded. After the first pass, the control unit 11 executes paper feeding and the second pass n times each, and backfeed between the second pass and paper feeding is executed n-1 times. The paper feed amounts for recording the second patch 42 for each of TP40a, 40e, 40d, 40c, and 40b are as explained with respect to Figures 3 and 4.

[0054] Multiple patches forming a TP may be recorded with liquids of the same color. That is, the control unit 11 records the first patch 41 and the second patch 42 forming a single TP with ink of the same color. Referring to Figure 7, for example, the first patch 41 and the second patch 42 forming TP 40a, and the first patch 41 and the second patch 42 forming TP 40e, are both recorded with C ink by the nozzle group 21C.

[0055] As can be seen from Figure 6, the TPs 40a, 40e, 40d, 40c, and 40b of TP group 43 are arranged at approximately equal intervals in the main scanning direction D1. In other words, the control unit 11 may control the recording head 19 to record n ​​TPs at equal intervals in the main scanning direction D1.

[0056] Furthermore, the control unit 11 may control the recording head 19 to record n ​​TPs in a symmetrical arrangement with respect to the center of the medium 30 in the main scanning direction D1. In the example shown in Figure 6, the TPs 40a, 40e, 40d, 40c, and 40b of the TP group 43 are arranged such that the central TP40d is positioned approximately in the center of the medium 30 in the main scanning direction D1, with TP40a, 40e and TP40c, 40b positioned approximately symmetrically to the left and right of TP40d.

[0057] Furthermore, the control unit 11 may control the recording head 19 to record information indicating the positional relationship of multiple patches forming a TP in the vicinity of each of the n TPs. In the example in Figure 6, the positional adjustment values ​​such as -2α, +2α, +α, 0, and -α correspond to information indicating the positional relationship of multiple patches. In other words, the positional adjustment value for each TP is also recorded along with the TP so that the user can see it. The vicinity of a TP means something like being adjacent in the main scanning direction D1 or the sub-scanning direction D2. For example, the positional adjustment value of TP40a, -2α, is recorded at the position closest to TP40a among TP40a, 40e, 40d, 40c, and 40b.

[0058] In step S110, the adjustment value calculation unit 12b of the control unit 11 acquires the read data of the TP group 43. That is, the reading device 1 reads the medium 30 on which the TP group 43 is recorded, and outputs the read data as a result of that reading to the recording device 10. In this way, the control unit 11 can acquire the read data of the TP group 43.

[0059] In step S120, the adjustment value calculation unit 12b obtains muscle concentrations for each TP 40a, 40b, 40c, 40d, and 40e from the reading data of TP group 43 and calculates an approximate straight line F3 of these muscle concentrations. Then, in step S130, the adjustment value calculation unit 12b obtains and saves the position adjustment value to which the approximate straight line F3 gives muscle concentration D0, and the flowchart in Figure 5 is completed.

[0060] In the lower section of Figure 6, the muscle concentrations for each TP40a, 40b, 40c, 40d, and 40e of TP group 43 are plotted as black circles corresponding to the position adjustment values ​​-2α, -α, 0, +α, and +2α in that order, and the approximate straight line F3 calculated from these muscle concentrations using the least squares method is also shown. Here, each muscle concentration shown as a black circle in the lower section of Figure 6 is the concentration obtained from the reading data of TP group 43 when skew occurs in the paper feed between the path for recording the first patch 41 and the path for recording the second patch 42, as explained in Figure 4. Furthermore, the muscle concentrations for each TP40a, 40b, 40c, 40d, and 40e obtained from the reading data of TP group 43 when no skew occurs in the paper feed between the path for recording the first patch 41 and the path for recording the second patch 42 are the same as the muscle concentrations for each TP40a, 40b, 40c, 40d, and 40e shown in the lower part of Figure 3.

[0061] In the lower section of Figure 6, for reference, the muscle concentrations for each TP 40a, 40b, 40c, 40d, and 40e, obtained from the reading data of TP group 43 when no skew occurred, are shown by white circles. For convenience, below, the muscle concentrations shown by black circles in the lower section of Figure 6 will be referred to as "muscle concentrations with skew," and the muscle concentrations shown by white circles in the lower section of Figure 6 will be referred to as "muscle concentrations without skew." The black arrows in the lower section of Figure 6 are vectors a, b, c, and e, which indicate the amount and direction of change from muscle concentrations without skew to muscle concentrations with skew due to the effect of skew.

[0062] First, let's focus on TP40a with a position adjustment value of -2α. TP40a is recorded as the leftmost of the TP group 43. Therefore, if skew occurs as shown by the dashed line in Figure 6, the distance between the first patch 41 and the second patch 42 will be shorter than when the position was adjusted with a position adjustment value of -2α in a non-skewed state. As shown by vector a, the muscle density with skew will be higher than the muscle density without skew. In other words, it will become darker.

[0063] Next, focusing on TP40b with a position adjustment value of -α, TP40b is recorded as being the rightmost of the TP group 43. Therefore, when skew occurs as shown by the dashed line in Figure 6, the distance between the first patch 41 and the second patch 42 widens compared to when the position is adjusted with a position adjustment value of -α in a non-skewed situation. As shown by vector b, the muscle density with skew becomes lower than the muscle density without skew. In other words, it becomes brighter.

[0064] Similarly, focusing on TP40c with a position adjustment value of 0, TP40c is recorded second from the right in the TP group 43. Therefore, when skew occurs as shown by the dashed line in Figure 6, the distance between the first patch 41 and the second patch 42 widens compared to when the position adjustment value is 0 in a skew-free situation. Consequently, although not as large as the change in muscle density from skew-free to skew-present in TP40b, which is recorded furthest to the right, the skew-present muscle density of TP40c also becomes lower than the skew-free muscle density, as shown by vector c. In other words, it becomes brighter.

[0065] Similarly, focusing on TP40d with a position adjustment value of +α, TP40d is recorded in the center of TP group 43. Therefore, even if skew occurs as shown by the dashed line in Figure 6, it is either virtually unaffected by the skew, or the skew effect is the smallest compared to the other TP40a, 40b, 40c, and 40e. Thus, the muscle concentration with skew in TP40d is the same as or almost the same as the muscle concentration without skew. In the lower part of Figure 6, the white circles representing muscle concentration without skew corresponding to a position adjustment value of +α overlap with the black circles representing muscle concentration with skew corresponding to a position adjustment value of +α, so their representation has been omitted.

[0066] Similarly, focusing on TP40e with a position adjustment value of +2α, TP40e is recorded second from the left in TP group 43. Therefore, when skew occurs as shown by the dashed line in Figure 6, the distance between the first patch 41 and the second patch 42 becomes shorter than when the position adjustment value is +2α in a skew-free situation. Thus, although not as large as the change in muscle density from skew-free to skew-present in TP40a, which is recorded furthest to the left, the skew-present muscle density of TP40e also becomes higher than the skew-free muscle density, as shown by vector e. In other words, it becomes darker.

[0067] According to these results, the vectors a, b, c, and e shown in the lower part of Figure 6 cancel each other out at relatively close positions within the graph. In other words, when looking at the skewed muscle concentration for each TP in TP group 43, the values ​​are different from the skewed muscle concentration. However, due to the random order of the TPs in TP group 43, the changes from skewed muscle concentration to skewed muscle concentration cancel each other out between vectors a and b, and between vectors c and e. Therefore, the approximate straight line F1 calculated from the skewed muscle concentration for each TP as shown in Figure 3 and the approximate straight line F3 calculated from the skewed muscle concentration for each TP as shown in Figure 6 are in close agreement. With this embodiment, whether or not skew occurs in the medium 30, almost the same position adjustment value can be obtained in step S130. That is, an appropriate position adjustment value with the effect of skew removed can be obtained based on the recording results of TP group 43.

[0068] We will now examine in more detail the effect of the random order of the TPs in TP group 43 in Figure 6. The approximation line described so far can be expressed as a linear function Y = pX + q, where X is the position adjustment value on the horizontal axis and Y is the muscle concentration on the vertical axis. p is the regression coefficient and q is the intercept. The regression coefficient p is expressed as the covariance of X and Y / the variance of X. Of these, the denominator "variance of X" is independent of whether or not the medium 30 is skewed, so we focus on the numerator "covariance of X and Y".

[0069] The covariance of X and Y is the average (Ave) of (the deviation of X × the deviation of Y), and is expressed by the following formula (1). Covariance of X and Y ={(X1 - X

[0070] )(Y1 - Y Ave )+(X2 - X Ave )(Y2 - Y Ave )+(X3 - X Ave )(Y3 - Y Ave )+(X4 - X Ave )(Y4 - Y Ave )+(X5 - X Ave )(Y5 - Y Ave )} / 5 …(1)

[0070] X1~X5 are the position adjustment values of TP40a, 40b, 40c, 40d, 40e. Since they are equally spaced, X2~X5 are defined as follows based on X1. X2 = X1 + 8 X3 = X1 + 16 X4 = X1 + 24 X5 = X1 + 32

[0071] Thus, formula (1) can be expressed by the following formula (2). Y1~Y5 are the muscle concentrations of TP40a, 40b, 40c, 40d, 40e. Covariance of X and Y ={X1(Y1 + Y2 + Y3 + Y4 + Y5)-X Ave (Y1 + Y2 + Y3 + Y4 + Y5)-5X1Y Ave +5X Ave Y Ave -80Y Ave +8(Y2 + 2Y3 + 3Y4 + 4Y5)} / 5 …(2)

[0072] When Y1~Y5 with the errors ε1~ε5 of muscle concentration due to skew are made Y1´~Y5´, depending on the order - independent arrangement, Y1´~Y5´ are as follows. Y1´ = Y1 + ε1 Y2´ = Y2 + ε5 Y3´ = Y3 + ε4 Y4´ = Y4 + ε3 Y5´ = Y5 + ε2

[0073] The numbers 1 to 5 for errors ε1 to ε5 are not sequential numbers like the numbers 1 to 5 for X1 to X5 or Y1 to Y5, such as TP40a, 40b, 40c, 40d, 40e, but rather numbers corresponding to the position order of the TP in the main scanning direction D1. For example, since TP40b is recorded at the far right, i.e., the 5th position from the left, the error ε5 is added to the muscle concentration Y2 of TP40b. Furthermore, assuming that the errors ε1 to ε5 are proportional to the distance from the center, with the signs reversed left and right with respect to the center ε3=0, they can be expressed as follows. ε1 = -2ε ε² = -ε ε3=0 ε₄ = ε ε5 = 2ε

[0074] Under these definitions, substitute Y1', Y2', Y3', Y4', and Y5' for Y1, Y2, Y3, Y4, and Y5 in equation (2). Ave or the average Y Ave This remains unchanged regardless of the presence or absence of skew. As a result of the substitution, the error component ε completely disappears in the term 8(Y2+2Y3+3Y4+4Y5), and similarly, the error component ε completely disappears in each term including the term (Y1+Y2+Y3+Y4+Y5), and consequently the covariance remains unchanged. In other words, the regression coefficient p does not change whether or not there is an error in muscle concentration due to skew. Also, the intercept q is Y Ave -pright Ave Therefore, if the regression coefficient p does not change, the intercept q also does not change. Accordingly, according to the recording of the TP group 43 using the random order of arrangement in this embodiment, the same approximate straight line can be calculated from the read data whether or not skew occurs in the medium 30 during paper feeding, and an appropriate position adjustment value that eliminates the effect of skew can be obtained.

[0075] Needless to say, the random order of the TPs in TP group 43 may be the reverse of the order shown in Figure 6, that is, from left to right, TP40b, 40c, 40d, 40e, 40a. Also, compared to the conventional TP group 40, for example, the positions of TP40b and TP40e may be swapped to create a random order of TP40a, 40e, 40c, 40d, 40b, or the positions of TP40c and TP40d may be swapped to create a random order of TP40a, 40b, 40d, 40c, 40e. In addition, there are various other ways to arrange TP40a, 40b, 40c, 40d, 40e randomly in the main scanning direction D1 compared to the conventional TP group 40. In any case, by adopting a random order for recording multiple TPs, the effect of suppressing the change in the approximate straight line due to the skew effect, as described above, is achieved when compared to TP group 40, making it possible to obtain position adjustment values ​​with reduced skew effects.

[0076] 4. Variations: As described above, the control unit 11 controls the recording head 19 to record a TP (Transaction Point) on the medium 30 that can acquire the amount of deviation between different paths. The amount of deviation may be the amount of deviation in the transport direction D2 as described above, or it may be the amount of deviation in the main scanning direction D1. The deviation in the main scanning direction D1 between different paths is the deviation between the recording by the forward path and the recording by the return path, that is, the deviation of bidirectional recording. Therefore, this modified example assumes bidirectional recording.

[0077] Figure 8A shows a portion of the medium 30 in which the TP recording control unit 12a controlled the recording head 19 to record the TP group 50 in step S100. The TP group 50 contains n TPs 50a, 50b, 50c, 50d, and 50e. According to the TP group 50, TPs 50a, 50b, 50c, 50d, and 50e are recorded in the order TP50a, 50e, 50d, 50c, and 50b from left to right along the main scanning direction D1. Each of TPs 50a, 50b, 50c, 50d, and 50e is formed by a first patch 51 on the left and a second patch 52 on the right. In Figure 8A, the reference numerals 51 and 52 are omitted for TPs 50a, 50b, 50d, and 50e other than TP50c.

[0078] Multiple patches 51 and 52 that form a single TP are recorded by different paths. That is, the first patch 51 is recorded on the forward path of the recording head 19, and the second patch 52 is recorded on the return path of the recording head 19. Furthermore, TPs 50a, 50b, 50c, 50d, and 50e are formed such that their positional relationship with the first patch 51 and the second patch 52 is different from that of the first patch 51 and the second patch 52, respectively. In Figure 8A, -2α, -α, 0, +α, and +2α are positional adjustment values ​​between the first patch 51 and the second patch 52 for TPs 50a, 50b, 50c, 50d, and 50e, respectively. α is a numerical value that represents a predetermined distance or predetermined time.

[0079] For example, if the position adjustment value is positive, the timing of recording the second patch 52, adjacent to the first patch 51 recorded on the outbound path, on the return path will be earlier, according to a value such as α or 2α, compared to when the position adjustment value is 0. +2α is earlier than +α. Therefore, TPs with a positive position adjustment value are more likely to record the second patch 52 at a position farther away from the first patch 51. Conversely, if the position adjustment value is negative, the timing of recording the second patch 52, adjacent to the first patch 51 recorded on the outbound path, on the return path will be delayed, according to a value such as α or 2α, compared to when the position adjustment value is 0. -2α is later than -α. Therefore, TPs with a negative position adjustment value are more likely to record the second patch 52 overlapping the first patch 51 more.

[0080] In other words, the TP group 50 consists of n TPs 50a, 50b, 50c, 50d, and 50e, recorded in an order different from the sequence "TP50a, 50b, 50c, 50d, and 50e in which the positional relationship between patches 51 and 52 gradually changes" along the main scanning direction D1. For the TP group 50, the black lines in the overlapping parts and the white lines in the gaps between patches 51 and 52 shown in Figure 8A are considered as black streaks and white streaks. As explained above, in steps S110 to S130, the control unit 11 obtains the muscle density for each TP 50a, 50b, 50c, 50d, and 50e from the read data of the TP group 50, and obtains a position adjustment value from the calculated approximation line. The position adjustment value here is a value used to adjust the timing of the recording of the return path relative to the recording of the forward path.

[0081] In the recording device 10, if the distance between the recording head 19 and the medium 30 during a given scan differs between one side and the other side in the main scanning direction D1, i.e., the left and right sides, due to mechanical errors in the device or other factors such as vibration, the time it takes for the dot ejected from the recording head 19 to land on the medium 30 will differ between the left and right sides. For example, if an external force such as vibration is applied to the recording device 10, and the distance between the recording head 19 and the medium 30 during recording differs between the left and right sides, black streaks are more likely to occur where the distance between the recording head 19 and the medium 30 is greater, while white streaks are more likely to occur where the distance is smaller. In other words, if the time until landing is long in the forward pass, the dot will land shifted in the forward direction, and conversely, if the time until landing is short, the dot will land shifted in the return direction from the intended position. If this difference in the distance between the recording head 19 and the medium 30 is considered in the same way as the skew described above, then it is necessary to devise a way to obtain a position adjustment value that minimizes the effect of this difference. Therefore, from this perspective, it can be said that recording the TP group 50 as shown in Figure 8A in this embodiment is beneficial.

[0082] In this modified example, the example of the TP group to be recorded on the medium 30 is not limited to the TP group 50 shown in Figure 8A, but may also be the TP group 53 shown in Figure 8B. Figure 8B shows a part of the medium 30 in which the TP recording control unit 12a controls the recording head 19 to record the TP group 53 in step S100. The TP group 53 includes n TPs 53a, 53b, 53c, 53d, and 53e. According to the TP group 53, TPs 53a, 53b, 53c, 53d, and 53e are recorded in the order of TPs 53a, 53e, 53d, 53c, and 53b from left to right along the main scanning direction D1. Each of the TPs 53a, 53b, 53c, 53d, and 53e is formed by a first patch 54 and a second patch 55. In Figure 8B, the reference numerals 54 and 55 are omitted for TP53a, 53b, 53c, and 53d, excluding TP53e.

[0083] The first patch 54 is composed of several lines with a length component in the sub-scanning direction D2, arranged in the main scanning direction D1. The second patch 55 is composed of several lines with a length component in the sub-scanning direction D2, arranged in the main scanning direction D1. For clarity, in Figure 8B, the lines of the first patch 54 are shown as dashed lines, and the lines of the second patch 55 are shown as solid lines. The term "patch" simply refers to an element that constitutes a TP, or a group of such elements. Therefore, the first patch 54 and the second patch 55 may also be referred to as, for example, the first pattern element 54, the second pattern element 55, or a group of lines.

[0084] In interpreting Figure 8B, the first patch 54 should be considered equivalent to the first patch 51 in Figure 8A, and the second patch 55 should be considered equivalent to the first patch 52 in Figure 8A. The position adjustment values ​​for TP53a, 53b, 53c, 53d, and 53e in Figure 8B, such as -2α, -α, 0, +α, and +2α, should be interpreted in the same way as in Figure 8A. Therefore, the TP group 53 consists of n TP53a, 53b, 53c, 53d, and 53e recorded in an order different from the order in which "TP53a, 53b, 53c, 53d, and 53e in which the positional relationship of patches 54 and 55 gradually changes" along the main scanning direction D1. For TP group 53, the amount of leftward shift of the second patch 55 line relative to the first patch 54 line in TP, obtained from the reading data, should be considered equivalent to the muscle density of black muscle as explained above, and the amount of rightward shift of the second patch 55 line relative to the first patch 54 line in TP should be considered equivalent to the muscle density of white muscle as explained above.

[0085] 5. Summary: As described above, according to this embodiment, the recording device 10 includes a recording head 19 having a plurality of nozzles 20 for discharging liquid into a medium 30, and a control unit 11 for controlling the recording head 19. Recording is performed on the medium 30 by scanning, which causes liquid to be discharged from the recording head 19 while moving the recording head 19 along a predetermined main scanning direction D1. When n is an integer of 3 or more, the control unit 11 controls the recording head 19 to record n ​​TPs on the medium 30 in the main scanning direction D1, which are capable of acquiring the amount of deviation between different scans. One TP is formed by a plurality of patches recorded by multiple scans, and the n TPs are formed such that the positional relationship of the plurality of patches is different from that of the others, and are recorded in an order different from the order in which the positional relationship of the plurality of patches gradually changes in the main scanning direction D1.

[0086] According to this configuration, the recording device 10 records multiple TPs in an unordered sequence in the main scanning direction D1. This makes it possible to obtain appropriate information from the recording results of multiple TPs, even if errors such as skew other than the misalignment of the adjustment target occur between the recording of a patch from an earlier scan and the recording of a patch from a later scan, thereby reducing the impact of such errors.

[0087] Furthermore, according to this embodiment, the amount of displacement is the amount of displacement of the medium 30 in the transport direction D2 intersecting the main scanning direction D1. According to the above configuration, even if skew occurs, the control unit 11 can obtain an appropriate adjustment value to eliminate the misalignment of the transport, thereby reducing the effects of such errors.

[0088] Furthermore, according to this embodiment, the control unit 11 may also make the positional relationship of multiple patches different for each TP by making the range in the transport direction D2 of the nozzle 20 used for recording patches different for each TP. According to the above configuration, the control unit 11 can record multiple TPs aligned in the main scanning direction D1 with the minimum number of scans.

[0089] The recording device 10 has a transport unit 17 that transports the medium 30 in the transport direction D2. Furthermore, the control unit 11 may make the transport distance that the transport unit 17 performs between scans to record each patch different for each TP, thereby making the positional relationship of multiple patches different for each TP. According to the above configuration, the control unit 11 reliably records multiple TPs in which the positional relationships of multiple patches are different from each other by actually varying the transport distance between scans for each TP.

[0090] Furthermore, according to this embodiment, the amount of displacement may be the amount of displacement in the main scanning direction D1. According to the above configuration, even if errors such as a difference in distance between the recording head 19 and the medium 30 occur between the recording of a patch by the earlier scan and the recording of a patch by the later scan, the control unit 11 can acquire an appropriate adjustment value to eliminate the misalignment of bidirectional recording, thereby reducing the effect of such errors. Note that the time between the recording of a patch by the earlier scan and the recording of a patch by the later scan includes not only the time interval but also the distance between the recording results of patches on the medium 30.

[0091] Furthermore, according to this embodiment, the control unit 11 controls the recording head 19 to record a first patch corresponding to each of the n TPs in a first scan, and to record a second patch corresponding to each of the n TPs in a second scan, with each second patch having a different position relative to the first patch. According to the above configuration, the control unit 11 can record at least the first patch of each TP in a single scan, thereby improving the recording efficiency of multiple TPs.

[0092] Furthermore, according to this embodiment, the multiple patches forming the TP may be recorded with liquids of the same color. According to the above configuration, it is possible to avoid various errors between nozzle groups or nozzle tips corresponding to different inks affecting the TP recording results. However, this embodiment does not exclude recording multiple patches forming a TP with different colored inks.

[0093] Furthermore, according to this embodiment, the n TPs may be recorded at equal intervals in the main scanning direction D1. Furthermore, according to this embodiment, the n TPs may be recorded in an arrangement that is symmetrical with respect to the center of the main scanning direction D1 of the medium 30. With these configurations, the effect of skew on the recording of each TP can be made proportional to the degree of influence depending on the position of the TP in the main scanning direction D1. Therefore, when evaluating the reading results of each TP or calculating the approximate straight line, these effects are more easily canceled out and eliminated.

[0094] Furthermore, according to this embodiment, the control unit 11 may control the recording head 19 to record information indicating the positional relationship of multiple patches forming a TP in the vicinity of each of the n TPs. According to the above configuration, the positional relationship of the multiple patches forming the TP can be clearly communicated to the user on the medium 30 on which the TP is recorded.

[0095] This embodiment discloses inventions in various categories, not limited to categories such as recording devices 10 and systems, but also including methods that these devices and systems perform, and programs 12 that cause a processor to perform these methods. For example, a recording method that records on a medium 30 by scanning while moving a recording head 19 having multiple nozzles 20 for discharging liquid onto the medium 30 along a predetermined main scanning direction D1 includes a recording control step that controls the recording head 19 to record n ​​TPs on the medium 30 in the main scanning direction D1, where n is an integer of 3 or more, and the amount of deviation between different scans can be obtained. Step S100 corresponds to the recording control step. According to the recording control step, one TP is formed by multiple patches recorded by multiple scans, and the n test patterns are formed such that the positional relationships of the multiple patches are different from each other, and are recorded in an order different from the order in which the positional relationships of the multiple patches gradually change in the main scanning direction D1.

[0096] Needless to say, n is not limited to 5. n can be 3, 4, or even 6 or more. Also, a single TP may consist of more than two patches. [Explanation of Symbols]

[0097] 1...Reading device, 10...Recording device, 11...Control unit, 12...Program, 12a...TP recording control unit, 12b...Adjustment value calculation unit, 13...Display unit, 14...Operation reception unit, 15...Storage unit, 16...Communication IF, 17...Transport unit, 18...Carriage, 19...Recording head, 20...Nozzle, 21C, 21M, 21Y, 21K...Nozzle group, 30...Media, 40a, 40b, 40c, 40d, 40e...TP, 41...First patch, 42...Second patch, 43...TP group, 50...TP group, 50a, 50b, 50c, 50d, 50e...TP, 51...First patch, 52...Second patch, 53...TP group, 53a, 53b, 53c, 53d, 53e...TP, 54...First patch, 55...Second patch

Claims

1. A recording head having multiple nozzles for dispensing liquid onto a medium, The system comprises a control unit for controlling the recording head, A recording device that records onto a medium by scanning while moving the recording head along a predetermined main scanning direction and discharging liquid from the recording head, The control unit controls the recording head to record n ​​test patterns capable of acquiring different deviation amounts between scans onto the medium in the main scanning direction, when n is an integer of 3 or more. One of the test patterns is formed by two patches recorded by two of the scans, The n test patterns are, The relative positional relationship of the two patches is formed to differ for each test pattern. In the aforementioned main scanning direction, the relative positional relationship of the two patches is recorded in an order different from the order in which it gradually changes. The two aforementioned patches are referred to as the first patch and the second patch. The control unit, For each of the test patterns, the density at the boundary between the first patch and the second patch is obtained. An approximate straight line on a graph is calculated, with the vertical axis representing the density at the boundary and the horizontal axis representing the positional adjustment value corresponding to the relative positional relationship between the first patch and the second patch. A recording device characterized by acquiring a position adjustment value when the approximate straight line gives a concentration that is not at the boundary between the two patches.

2. The recording device according to claim 1, characterized in that the amount of displacement is the amount of displacement in the transport direction of the medium intersecting the main scanning direction.

3. The recording device according to claim 2, characterized in that the control unit causes the relative positional relationship between the two patches to differ for each test pattern by changing the range of the nozzle used for recording the patch in the transport direction for each test pattern.

4. It has a conveying unit that conveys the medium in the aforementioned conveying direction, The recording apparatus according to claim 2, characterized in that the control unit causes the transport unit to perform the transport distance between the scan for recording the first patch and the scan for recording the second patch to differ for each test pattern, thereby causing the relative positional relationship of the two patches to differ for each test pattern.

5. The recording device according to claim 1, characterized in that the amount of displacement is the amount of displacement in the main scanning direction.

6. The control unit controls the recording head, The first scan records the first patch corresponding to each of the n test patterns. The recording device according to any one of claims 1 to 5, characterized in that the second scan causes the second patch corresponding to each of the n test patterns to be recorded, with each second patch having a different position relative to the first patch.

7. The recording device according to any one of claims 1 to 5, characterized in that the two patches forming the test pattern are recorded with a liquid of the same color.

8. The recording device according to any one of claims 1 to 5, characterized in that the n test patterns are recorded at equal intervals in the main scanning direction.

9. The recording device according to any one of claims 1 to 5, characterized in that the n test patterns are recorded in an arrangement that is symmetrical with respect to the center of the medium in the main scanning direction.

10. The recording apparatus according to any one of claims 1 to 5, characterized in that the control unit controls the recording head to record information indicating the relative positional relationship between the two patches that form the test pattern in the vicinity of each of the n test patterns.

11. A method for obtaining a position adjustment value for a recording device that records onto a medium by scanning while moving a recording head having multiple nozzles for discharging liquid onto the medium along a predetermined main scanning direction, wherein the recording device records onto the medium by discharging liquid onto the recording head, When n is an integer of 3 or more, the recording control step controls the recording head to record n ​​test patterns on the medium in the main scanning direction, each test pattern capable of obtaining different deviation amounts between scans. In the aforementioned recording control process, One of the test patterns is formed by two patches recorded by two of the scans, The n test patterns are, The relative positional relationship of the two patches is formed to differ for each test pattern. In the aforementioned main scanning direction, the relative positional relationship of the two patches is recorded in an order different from the order in which it gradually changes. The two aforementioned patches are referred to as the first patch and the second patch. The method for obtaining the position adjustment value is as follows: A step of obtaining the concentration at the boundary between the first patch and the second patch for each of the test patterns, A step of calculating an approximate straight line on a graph where the vertical axis is the density at the boundary and the horizontal axis is the position adjustment value corresponding to the relative positional relationship between the first patch and the second patch, A method for obtaining a position adjustment value for a recording device, characterized by comprising the step of obtaining a position adjustment value when the approximate straight line gives a density that is not at the boundary between the two patches.

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