printer

Abstract

To enhance accuracy in adjusting bidirectional printing.SOLUTION: In a printer 100, an adjustment pattern printing part 61 prints an adjustment pattern PT1 on a medium 5, by making an ink head 28 discharge ink while moving the ink head 28 in a forward direction Y1 and in a backward direction Y2. A sensor movement control part 67 moves a sensor head 36 having a sensor 38 so that the sensor 38 scans on a pattern portion C1 formed of ink discharged by a center nozzle 42 in a nozzle row 41 of the ink head 28, of the adjustment patterns PT1 printed on the medium 5. A reading part 69 makes the sensor 38 read out the pattern portion C1 in the adjustment pattern PT1 during the movement of the sensor head 36. A determining part 71 determines an adjustment value V1 for adjusting an impacting position of ink in bidirectional printing, on the basis of a read-out result of the pattern portion C1 by the reading part 69.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a printer.

Background Art

[0002] For example, Patent Document 1 discloses a printer capable of bidirectional printing. The printer has an ink head that discharges ink and is movable in the main scanning direction. In bidirectional printing, printing is performed on the medium both when the ink head is moving in the forward path of the main scanning direction and when it is moving in the return path.

[0003] By the way, in a printer capable of bidirectional printing, when discharging ink from the ink head so that the ink lands at the same position on the medium during the forward movement and the return movement of the ink head in the main scanning direction, the landing position of the ink may deviate in the main scanning direction. Therefore, Patent Document 1 discloses adjusting the deviation of the ink landing position in bidirectional printing.

[0004] In the printer disclosed in Patent Document 1, an adjustment pattern is printed on the medium. The adjustment pattern is composed of a plurality of first print blocks arranged at regular intervals in a predetermined direction and a plurality of second print blocks paired with the first print blocks. The second print blocks are printed shifted by a predetermined interval with respect to the paired first print blocks as going in a predetermined direction. The deviation amount between the paired first print blocks and second print blocks becomes an adjustment value. Here, the first print blocks are printed when the ink head is moving in the forward path of the main scanning direction, and the second print blocks are printed when the ink head is moving in the return path of the main scanning direction. Here, based on the adjustment value set for the pair with the smallest interval between the first print blocks and the second print blocks, the adjustment of the ink landing position in bidirectional printing is performed.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2004-243553 [Overview of the project] [Problems that the invention aims to solve]

[0006] Incidentally, the ink head has a nozzle row composed of multiple nozzles arranged in the sub-scanning direction. However, depending on the ink head, the accuracy of the ink landing position may decrease as you move from the center of the nozzle row toward the edges in the sub-scanning direction. Therefore, if an adjustment pattern is printed using nozzles located toward the edges of the nozzle row in the sub-scanning direction, it may not be possible to calculate accurate adjustment values. As a result, the accuracy of adjusting the ink landing position in bidirectional printing may decrease.

[0007] This invention has been made in view of the above, and its purpose is to provide a printer that can improve the accuracy of adjusting the ink landing position in bidirectional printing. [Means for solving the problem]

[0008] The printer according to the present invention comprises a support base, an ink head, a sensor head, a moving mechanism, and a control device. The support base supports a medium. The ink head ejects ink onto the medium supported by the support base. The sensor head has a sensor that reads an adjustment pattern printed on the medium, which is used to adjust the landing position of ink from the ink head in bidirectional printing. The moving mechanism moves the ink head in the main scanning direction during printing and moves the sensor head in the main scanning direction when reading the adjustment pattern. The ink head has a nozzle row in which a plurality of nozzles that eject ink are arranged in the sub-scanning direction. The nozzle row has a central nozzle located in the central part of the nozzle row in the sub-scanning direction. The length of the adjustment pattern printed on the medium in the sub-scanning direction is less than or equal to the length of the nozzle row. The direction from one main scanning direction to the other is the forward path, and the direction from the other main scanning direction to the one is the return path. The control device comprises an adjustment pattern printing unit, a sensor moving control unit, a reading unit, and a determination unit. The adjustment pattern printing unit prints the adjustment pattern onto the medium by ejecting ink from the ink head while moving the ink head in the forward and return directions. The sensor movement control unit controls the movement of the sensor head so that the sensor scans over the pattern portion of the adjustment pattern printed on the medium, which is formed by the ink ejected by the central nozzle. The reading unit reads the pattern portion of the adjustment pattern using the sensor while the sensor head is moving by the sensor movement control unit. The determination unit determines an adjustment value for adjusting the ink landing position in bidirectional printing based on the reading result of the pattern portion by the reading unit.

[0009] According to the above printer, the accuracy of the ink landing position ejected from the central nozzle of the nozzle row is relatively good. Therefore, in the adjustment pattern used to adjust the ink landing position from the ink head in bidirectional printing, a more accurate adjustment value can be determined by reading the pattern portion printed by the central nozzle, which has good ink landing position accuracy, with a sensor. Thus, the accuracy of adjusting the ink landing position in bidirectional printing can be improved. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a printer that can improve the accuracy of adjusting the ink landing position in bidirectional printing. [Brief explanation of the drawing]

[0011] [Figure 1] This is a front view of the printer according to the embodiment. [Figure 2] This diagram schematically shows the configuration of the underside of the print head. [Figure 3] This is a block diagram of the printer according to the embodiment. [Figure 4] This is a flowchart showing the procedure for adjusting bidirectional printing. [Figure 5] This diagram schematically shows an example of an adjustment pattern. [Figure 6] This is a diagram showing the adjustment set G1f and the reference figure. [Figure 7] This diagram schematically shows the first adjustment pattern. [Figure 8] This figure shows the first and second approximate lines. [Modes for carrying out the invention]

[0012] Hereinafter, embodiments of the printer according to the present invention will be described with reference to the drawings. It should be noted that the embodiments described herein are not intended to particularly limit the present invention.

[0013] Figure 1 is a front view of the printer 100 according to this embodiment. The symbols F, Rr, L, R, U, and D in the drawing indicate the front, back, left, right, top, and bottom of the printer 100, respectively. The symbol Y indicates the main scanning direction. The main scanning direction Y is, for example, the left-right direction. The direction from one side (here, the right) to the other side (here, the left) of the main scanning direction Y is called the forward path direction Y1. The direction from the other side to the first side of the main scanning direction Y is called the return path direction Y2. The symbol X indicates the sub-scanning direction. The sub-scanning direction X is, for example, the front-back direction. In a plan view, the sub-scanning direction X intersects (here, is orthogonal to) the main scanning direction Y. However, these directions are merely defined for the convenience of explanation and do not limit the installation configuration of the printer 100 or the present invention in any way.

[0014] Printer 100 is an inkjet printer. As shown in Figure 1, printer 100 prints on medium 5. Medium 5 is, for example, a roll of recording paper, but the material forming medium 5 is not particularly limited.

[0015] The printer 100 comprises a printer body 11. The printer body 11 is supported by legs 12. The printer body 11 is equipped with a touch panel 13. The touch panel 13 is configured to display information regarding the status of the printer 100 and the adjustment of bidirectional printing, and to allow the user to perform operations, such as inputting information related to bidirectional printing.

[0016] The printer 100 includes a platen 18 that supports the medium 5, and a transport mechanism 20 that transports the medium 5 supported by the platen 18 in the sub-scanning direction X. The platen 18 is an example of a support base. The medium 5 is placed on the platen 18. Printing is performed on the medium 5 on the platen 18. The transport mechanism 20 includes, for example, a grit roller 21 provided on the platen 18, a pinch roller 22 disposed above the grit roller 21 and sandwiching the medium 5 together with the grit roller 21, and a feed motor 23 connected to the grit roller 21. When the feed motor 23 is driven and the grit roller 21 rotates, the medium 5 is transported in the sub-scanning direction X.

[0017] As shown in FIG. 1, the printer 100 includes a guide rail 25 extending in the main scanning direction Y above the platen 18, a print head 26, and a sensor head 36. The print head 26 is configured to be movable in the main scanning direction Y. The print head 26 includes an ink carriage 27 and a plurality of ink heads 28 (see FIG. 2). The ink carriage 27 is slidably engaged with the guide rail 25.

[0018] The ink head 28 discharges ink toward the medium 5 supported by the platen 18. FIG. 2 is a diagram schematically showing the configuration of the lower surface of the print head 26. The number of ink heads 28 is not particularly limited, but here, as shown in FIG. 2, it is four. The four ink heads 28 are supported by the ink carriage 27. The four ink heads 28 are arranged side by side in the main scanning direction Y. A plurality of nozzles 40 through which ink is discharged are formed on the lower surface of one ink head 28. The plurality of nozzles 40 are arranged side by side in the sub-scanning direction X. Here, a row of the plurality of nozzles 40 arranged side by side in the sub-scanning direction X is referred to as a nozzle row 41. Here, in one ink head 28, two nozzle rows 41 are provided. Therefore, in the printer 100 according to the present embodiment, eight nozzle rows 41 are provided. The plurality of nozzle rows 41 may be arranged at the same position in the sub-scanning direction X, or may be arranged at positions shifted in the sub-scanning direction X.

[0019] In this embodiment, each nozzle row 41 has a central nozzle 42. The central nozzle 42 refers to a nozzle 40 located at the central portion of the nozzle row 41 in the sub-scanning direction X. The number of nozzles 40 included in the central nozzle 42 is not particularly limited, but for example, it is plural. Here, the central nozzle 42 is, for example, a nozzle 40 located in the second range from the front (here, the range located at the center) when the nozzle row 41 is divided into three parts (for example, equally divided) in the sub-scanning direction X. However, the central nozzle 42 may be a nozzle 40 located in the third range from the front (here, the range located at the center) when the nozzle row 41 is divided into five parts (for example, equally divided) in the sub-scanning direction X. Also, the central nozzle 42 may be a nozzle 40 located in the fourth range from the front (here, the range located at the center) when the nozzle row 41 is divided into seven parts (for example, equally divided) in the sub-scanning direction X.

[0020] In this embodiment, the plurality of nozzle rows 41 eject inks of different colors from the nozzles 40. For example, each nozzle row 41 ejects any one of characteristic inks such as process color inks and clear inks. Here, the plurality of nozzle rows 41 eject inks of the colors cyan, magenta, yellow, black, light magenta, light cyan, light black, and orange from the nozzles 40 in order from left to right. However, the order of arrangement of the ink colors in the plurality of nozzle rows 41 is not particularly limited. Also, inks of the same color may be ejected from some of the plurality of nozzle rows 41.

[0021] As shown in FIG. 1, the sensor head 36 is arranged side by side with the print head 26 in the main scanning direction Y and is configured to be movable in the main scanning direction Y. The sensor head 36 has a sensor carriage 37 and a sensor 38. The sensor carriage 37 is slidably engaged with the guide rail 25.

[0022] The sensor 38 is supported by the sensor carriage 37. The sensor 38 is a sensor for reading the adjustment pattern PT1 (see Figure 5), described later, which is used to adjust the landing position of ink from the ink head 28 in bidirectional printing, and which is printed on the medium 5. The sensor 38 reads the position of the adjustment pattern PT1 relative to the medium 5, and also reads the position of the boundary between the adjustment pattern PT1 and the medium 5. The type of sensor 38 is not particularly limited, but for example it is optical. The sensor 38 is, for example, a color sensor. The sensor 38 is a sensor that is capable of detecting color and, for example, can represent color using RGB.

[0023] In this embodiment, as shown in Figure 1, the print head 26 and the sensor head 36 are connectable. The sensor head 36 can move independently in the main scanning direction Y, away from the print head 26. The print head 26 can be connected to the sensor head 36 and move together with the sensor head 36 in the main scanning direction Y.

[0024] The printer 100 is equipped with a moving mechanism 30 that moves the ink head 28 in the main scanning direction Y during printing and moves the sensor head 36 in the main scanning direction Y when reading the adjustment pattern PT1 (see Figure 5) printed on the medium 5. The moving mechanism 30 comprises left and right pulleys 31a and 31b provided around the left and right ends of the guide rail 25, a belt 32 wrapped around the left and right pulleys 31a and 31b, and a carriage motor 33 connected to the right pulley 31b. The sensor head 36 is fixed to the belt 32. Here, the carriage motor 33 is driven, causing the right pulley 31b to rotate and the belt 32 to move. This causes the sensor head 36 to move in the main scanning direction Y. When the print head 26 is connected to the sensor head 36, the print head 26 moves in the main scanning direction Y together with the sensor head 36.

[0025] The printer 100 is equipped with a control device 50. The control device 50 is composed of, for example, a microcomputer. The control device 50 includes, for example, an interface (I / F) for receiving print data from an external device such as a host computer, a central processing unit (CPU) for executing instructions of the control program, a read-only memory (ROM) for storing the program executed by the CPU, a random access memory (RAM) used as a working area for expanding the program, and a memory for storing the program and various data. The control device 50 does not necessarily have to be located inside the printer 100; for example, it may be installed outside the printer 100 and connected to the printer 100 via wired or wireless communication, such as a computer.

[0026] Figure 3 is a block diagram of the printer 100 according to this embodiment. In this embodiment, as shown in Figure 3, the control device 50 is connected to the touch panel 13, the transport mechanism 20 (specifically the feed motor 23), the ink head 28, the moving mechanism 30 (specifically the carriage motor 33), and the sensor 38 in a manner that allows communication between them. The control device 50 is configured to control the touch panel 13, the transport mechanism 20, the ink head 28, the moving mechanism 30, and the sensor 38.

[0027] By the way, the printer 100 according to this embodiment is capable of bidirectional printing. Here, bidirectional printing means that when the ink head 28 is moving in the forward path direction Y1 of the main scanning direction Y, ink is ejected from the ink head 28 to print on the medium 5 (hereinafter referred to as forward printing), and when the ink head 28 is moving in the return path direction Y2, ink is ejected from the ink head 28 to print on the medium 5 (hereinafter referred to as return printing). When attempting to eject ink to the same position on the medium 5 in both forward and return printing, a discrepancy in the main scanning direction Y may occur in the ink landing position. In this case, for example, the ink landing position in bidirectional printing is adjusted by adjusting the ink ejection timing in return printing (hereinafter referred to as bidirectional printing adjustment). Here, the value used for bidirectional printing adjustment is called the adjustment value V1 (see Figure 8).

[0028] In this embodiment, the adjustment value V1 is automatically determined by the control device 50. Here, in order to adjust bidirectional printing, the control device 50 includes, as shown in Figure 3, a storage unit 52, an adjustment pattern printing unit 61, a threshold setting unit 62, a position detection unit 63, a centerline calculation unit 65, a sensor movement control unit 67, a reading unit 69, and a determination unit 71. Each of the parts 52 to 71 of the control device 50 may be configured by software or by hardware. For example, each of the parts 52 to 71 of the control device 50 may be performed by one or more processors or incorporated into a circuit. Details of each of the parts 52 to 71 of the control device 50 will be described later.

[0029] Next, the procedure for adjusting bidirectional printing will be explained using the flowchart in Figure 4. In this embodiment, for example, a start button (not shown) for starting the adjustment of bidirectional printing is displayed on the touch panel 13 (see Figure 1). The user operates the touch panel 13 and presses the start button, which automatically starts the process of adjusting bidirectional printing. Adjustment of bidirectional printing is performed, for example, when the medium 5 is attached to the platen 18. Note that during the adjustment of bidirectional printing, a print start button (not shown) for starting the printing of the print image is not displayed on the touch panel 13. This prevents the user from accidentally starting the printing of the print image by touching the print start button or performing other misoperations during the adjustment of bidirectional printing.

[0030] Figure 5 is a schematic diagram showing an example of the adjustment pattern PT1. First, in step S101 in Figure 4, the adjustment pattern printing unit 61 in Figure 3 prints the adjustment pattern PT1, as shown in Figure 5, onto the medium 5 (see Figure 1) supported by the platen 18. Furthermore, the adjustment pattern printing unit 61 prints the reference figure F5 (see Figure 5) along with the adjustment pattern PT1 onto the medium 5. The adjustment pattern PT1 and the reference figure F5 are printed on the medium 5 when adjusting for bidirectional printing.

[0031] In this embodiment, adjustment pattern PT1 exists for each ink color. Here, it is possible to eject eight colors of ink from eight nozzle rows 41 (see Figure 2). Therefore, there are a total of eight adjustment patterns PT1, from the first adjustment pattern PT1a to the eighth adjustment pattern PT1h. The first adjustment pattern PT1a to the eighth adjustment pattern PT1h are patterns printed with different colored inks. For example, the first adjustment pattern PT1a, the second adjustment pattern PT1b, the third adjustment pattern PT1c, and the fourth adjustment pattern PT1d are patterns printed with cyan, magenta, yellow, and black inks, respectively. The fifth adjustment pattern PT1e, the sixth adjustment pattern PT1f, the seventh adjustment pattern PT1g, and the eighth adjustment pattern PT1h are patterns printed with light magenta, light cyan, light black, and orange inks, respectively.

[0032] Here, as shown in Figure 5, the first adjustment pattern PT1a to the eighth adjustment pattern PT1h are arranged in line along the sub-scanning direction X. More specifically, they are arranged in the order of the first adjustment pattern PT1a to the eighth adjustment pattern PT1h from front to back along the sub-scanning direction X. The first adjustment patterns PT1a to the eighth adjustment patterns PT1h adjacent to each other in the sub-scanning direction X may be touching but not separated.

[0033] In this embodiment, one adjustment pattern PT1 has a forward pattern PT11 and a return pattern PT12. The forward pattern PT11 is printed when the ink head 28 is moving in the forward direction Y1. For one adjustment pattern PT1, the forward pattern PT11 has a plurality of first figures F1 arranged in the main scanning direction Y. The forward pattern PT11 is a pattern in which the first figures F1 are arranged in the main scanning direction Y. The number of first figures F1 arranged in the main scanning direction Y is not particularly limited, but here there are six. The first figures F1 are rectangular (more specifically square), but the shape of the first figures F1 is not particularly limited.

[0034] The return path pattern PT12 is printed when the ink head 28 is moving in the return path direction Y2. For each adjustment pattern PT1, the return path pattern PT12 has multiple second shapes F2. The return path pattern PT12 is a pattern in which the second shapes F2 are arranged in the main scanning direction Y in conjunction with the first shapes F1. The number of second shapes F2 arranged in the main scanning direction Y is not particularly limited, but here there are six, the same as the first shapes F1. The second shapes F2 have the same shape as the first shapes F1, and are rectangular (more specifically, square), but the shape of the second shapes F2 is also not particularly limited.

[0035] In this embodiment, for each of the first adjustment patterns PT1a to PT1h, there exists a forward path pattern PT11 having a first figure F1 aligned in the main scanning direction Y, and a return path pattern PT12 having a second figure F2 aligned in the main scanning direction Y. Figure 6 shows a part of each adjustment pattern PT1 (here, adjustment set G1f) and a reference figure F5. As shown in Figure 6, the first figure F1 in each adjustment pattern PT1a to PT1h is arranged so as to be tangent to the sub-scanning direction X. Similarly, the second figure F2 in each adjustment pattern PT1a to PT1h is also arranged so as to be tangent to the sub-scanning direction X.

[0036] In this embodiment, as shown in Figure 5, for each adjustment pattern PT1, each of the multiple second figures F2 is paired with a first figure F1. Here, the paired first figure F1 and second figure F2 are called an adjustment set G1. There are six adjustment sets G1. In each adjustment set G1, the first figure F1 and the second figure F2 are spaced apart and do not overlap. In the following description, the adjustment sets G1 will be appropriately labeled with symbols G1a to G1f from left to right. In adjustment sets G1a, G1b, and G1c, the first figure F1 is positioned to the left of the second figure F2. The distance between the first figure F1 and the second figure F2 (here, the distance in the main scanning direction Y) increases in the order of adjustment sets G1c, G1b, and G1a. In adjustment sets G1d, G1e, and G1f, the first figure F1 is positioned to the right of the second figure F2. In the order of adjustment sets G1d, G1e, and G1f, the distance between the first figure F1 and the second figure F2 (here, the distance in the main scanning direction Y) increases. In this embodiment, the position of the first figure F1 relative to the second figure F2 in the main scanning direction Y differs in adjacent adjustment sets G1.

[0037] Furthermore, in each adjustment pattern PT1, the positions of the main scan direction Y of the forward pattern PT11 and the return pattern PT12 may be swapped. That is, in each adjustment set G1, the positions of the main scan direction Y of the forward pattern PT11 and the return pattern PT12 may be swapped, or in other words, the positions of the main scan direction Y of the first figure F1 and the second figure F2 may be swapped. Specifically, in adjustment sets G1a, G1b, and G1c, the first figure F1 may be positioned to the right of the second figure F2. In adjustment sets G1d, G1e, and G1f, the first figure F1 may be positioned to the left of the second figure F2.

[0038] Here, a candidate adjustment value V2 is set for each adjustment set G1. The candidate adjustment value V2 is the deviation of the first figure F1 in the main scanning direction Y relative to the second figure F2 in each adjustment set G1. Here, the candidate adjustment values ​​V2 for adjustment sets G1a to G1f are referred to as candidate adjustment values ​​V2a to V2f, respectively. For example, the candidate adjustment value V2 will be a negative value when the first figure F1 is shifted to the left relative to the second figure F2, and a positive value when it is shifted to the right. Note that the candidate adjustment value V2 is a data value (in other words, a logical value) and may differ from the deviation of the main scanning direction Y between the first figure F1 and the second figure F2 that is actually printed on the medium 5.

[0039] As described above, as shown in Figure 5, a reference figure F5 is printed on the medium 5 along with each adjustment pattern PT1. The reference figure F5 is positioned to the right of the adjustment pattern PT1, but it may also be positioned to the left. The reference figure F5 is printed on the medium 5 with a predetermined reference color ink from among several ink colors. Here, the reference color is black. The reference figure F5 is positioned in the main scanning direction Y alongside the fourth adjustment pattern PT1d, which is printed with black ink, among the multiple adjustment patterns PT1. The size and shape of the reference figure F5 are not particularly limited. Here, the reference figure F5 is the same size and shape as the first figure F1 and the second figure F2. The reference figure F5 is rectangular (more specifically, square).

[0040] In this embodiment, the storage unit 52 of the control device 50 (see Figure 3) stores print data for adjustment patterns PT1 (for example, the first adjustment pattern PT1a to the eighth adjustment pattern PT1h). In step S101 of Figure 4, the adjustment pattern printing unit 61 of Figure 3 prints the forward pattern PT11 (here, the first figure F1) of each adjustment pattern PT1 when the ink head 28 is moving in the forward direction Y1. The adjustment pattern printing unit 61 prints the return pattern PT12 (here, the second figure F2) of each adjustment pattern PT1 when the ink head 28 is moving in the return direction Y2. Here, the first adjustment pattern PT1a to the eighth adjustment pattern PT1h are printed on the medium 5 by the ink head 28 moving back and forth multiple times in the main scanning direction Y. Each adjustment pattern PT1 is printed on the medium 5 by ejecting ink from at least the central nozzle 42 (see Figure 2) of the nozzle row 41. The length L11 (see Figure 6) of the sub-scanning direction X of one adjustment pattern PT1 is less than or equal to the length L12 (see Figure 2) of the nozzle row 41. Note that length L11 is the length of the sub-scanning direction X of the first figure F1 and the length of the sub-scanning direction X of the second figure F2.

[0041] In this embodiment, the adjustment pattern printing unit 61 in Figure 3 prints the reference figure F5 (see Figure 5) along with each adjustment pattern PT1 onto the medium 5. Here, the adjustment pattern printing unit 61 prints the reference figure F5 when printing the fourth adjustment pattern PT1d with black ink. The reference figure F5 may be printed when the ink head 28 is moving in the forward direction Y1, or when the ink head 28 is moving in the return direction Y2.

[0042] Thus, after each adjustment pattern PT1 and reference figure F5 are printed on the medium 5, in step S103 of Figure 4, the threshold setting unit 62 of Figure 3 sets a threshold V50 for black and white determination. Here, the threshold V50 for black and white determination is a threshold for adjusting the reflectance of the medium 5, and is a threshold of the sensor 38 set by the white area and the black area of ​​the medium 5. The white area of ​​the medium 5 is, for example, the area of ​​the medium 5 on which the adjustment pattern PT1 or reference figure F5 is not printed. White is the background color of the medium 5. The black area of ​​the medium 5 is the area corresponding to the reference figure F5 printed on the medium 5.

[0043] In this embodiment, the threshold V50 can be set using the sensor 38. For example, the sensor 38 has a light-emitting part that emits light and a light-receiving part that receives light. The threshold setting unit 62 emits light from the light-emitting part of the sensor 38 toward a reference figure F5 formed with black ink (for example, the center of the reference figure F5). The light emitted from the light-emitting part is reflected by the reference figure F5 and received by the light-receiving part of the sensor 38. The threshold setting unit 62 obtains the black light-receiving value when the light-receiving part of the sensor 38 receives the light reflected from the reference figure F5. Next, the light-emitting part of the sensor 38 emits light toward an area of ​​the unprinted medium 5 (for example, the area between the reference figure F5 and the fourth adjustment pattern PT1d). The light emitted from the light-emitting part is reflected by the white area of ​​the medium 5 and received by the light-receiving part of the sensor 38. The threshold setting unit 62 obtains the white light-receiving value when the light-receiving part of the sensor 38 receives the light reflected from the white area of ​​the medium 5. The threshold setting unit 62 then sets the average value of the black light reception value and the white light reception value, that is, the value obtained by adding the black light reception value and the white light reception value and dividing by 2, as the black / white determination threshold V50.

[0044] Next, in step S105 of Figure 4, the center line L1 (see Figure 5) in the sub-scanning direction X of each adjustment pattern PT1 (here, the first adjustment pattern PT1a to the eighth adjustment pattern PT1h) is calculated. Here, the center line L1 can also be said to be the center line in the sub-scanning direction X of the pattern portion C1 formed by the ink ejected from the central nozzle 42 in each adjustment pattern PT1. In this embodiment, by calculating the figure center line L2 (see Figure 5) in the sub-scanning direction X of the reference figure F5, the center line L1 of each adjustment pattern PT1, in other words, the center line L1 of the pattern portion C1 formed by the ink ejected from the central nozzle 42 can be calculated.

[0045] Here, first, the position detection unit 63 in Figure 3 detects the positions of both ends of the reference figure F5 in the sub-scanning direction X. For example, the position detection unit 63 detects the positions of the front and rear ends of the reference figure F5. The position detection unit 63 controls the transport mechanism 20 and the moving mechanism 30 so that, for example, the sensor 38 scans the reference figure F5 in the sub-scanning direction X. At this time, the sensor 38 can detect the position of the boundary between the reference figure F5 and the background color of the medium 5 in the sub-scanning direction X, thereby detecting the positions of the front and rear ends of the reference figure F5.

[0046] Next, the centerline calculation unit 65 in Figure 3 calculates the figure centerline L2 (see Figure 5) that passes through the center of the sub-scanning direction X in the reference figure F5, based on the positions of both ends of the sub-scanning direction X of the reference figure F5. Here, the figure centerline L2 is a line that passes through the midpoint between the front and rear ends of the reference figure F5 and extends in the main scanning direction Y.

[0047] In this embodiment, the relative position of each adjustment pattern PT1 with respect to the reference figure F5 is pre-stored in the storage unit 52. Therefore, the centerline calculation unit 65 can uniquely determine the centerline L1 in each adjustment pattern PT1, or in other words, the centerline L1 in the pattern portion C1, once the figure centerline L2 is determined. In this embodiment, as shown in Figure 5, the centerline L1 is a line that passes through the center of the sub-scanning direction X of the first figure F1 and also passes through the center of the sub-scanning direction X of the second figure F2 in each adjustment pattern PT1. The centerline L1 is a line that extends in the main scanning direction Y. The information regarding the centerline L1 in each adjustment pattern PT1 (or in other words, the pattern portion C1) and the figure centerline L2 calculated by the centerline calculation unit 65 is stored in the storage unit 52 shown in Figure 3.

[0048] In the above, the center line L1 of each adjustment pattern PT1, i.e., the first adjustment pattern PT1a to the eighth adjustment pattern PT1h (in other words, the center line L1 of the pattern portion C1 of each adjustment pattern PT1) was calculated based on the center line L2 of the reference figure F5. However, the center line calculation unit 65 can calculate the center line L1 without using the reference figure F5.

[0049] The following describes the procedure for calculating the center line L1 of the first adjustment pattern PT1a without using the reference figure F5. First, the position detection unit 63 in Figure 3 detects the positions of both ends (in this case, the front end and rear end) of the sub-scanning direction X of the first adjustment pattern PT1a. The position detection unit 63 controls the transport mechanism 20 and the moving mechanism 30 so that, for example, the sensor 38 scans the first figure F1 (or second figure F2) of the first adjustment pattern PT1a in the sub-scanning direction X. At this time, the sensor 38 can detect the position of the boundary of the sub-scanning direction X of the first figure F1 (or second figure F2), thereby detecting the positions of both ends of the sub-scanning direction X of the first adjustment pattern PT1a.

[0050] Next, the centerline calculation unit 65 in Figure 3 calculates a centerline L1 that passes through the center of the sub-scanning direction X in the first adjustment pattern PT1 (in other words, pattern portion C1) based on the positions of both ends of the sub-scanning direction X in the first adjustment pattern PT1a. Here, the centerline L1 in the first adjustment pattern PT1a is a line that passes through the midpoint between the front and rear ends of the first adjustment pattern PT1a and extends in the main scanning direction Y. In a similar procedure, after the position detection unit 63 detects the positions of both ends of the sub-scanning direction X in the second adjustment pattern PT1b to the eighth adjustment pattern PT1h, the centerline calculation unit 65 can calculate the centerline L1 in the second adjustment pattern PT1b to the eighth adjustment pattern PT1h.

[0051] After calculating the center line L1 of each adjustment pattern PT1 as described above, in step S107, the sensor movement control unit 67 in Figure 3 controls the movement of the sensor head 36 by controlling the transport mechanism 20 and the movement mechanism 30 so that the sensor 38 scans the adjustment pattern PT1. The procedure for calculating the adjustment value V1 for cyan ink by having the sensor 38 scan the first adjustment pattern PT1a will be described below.

[0052] Figure 7 is a schematic diagram of the first adjustment pattern PT1a. In step S107, the sensor movement control unit 67 controls the transport mechanism 20 and the movement mechanism 30 so that the sensor 38 scans the pattern portion C1 formed by ink ejected by the central nozzle 42 (see Figure 2) of the nozzle row 41 in the first adjustment pattern PT1a printed on the medium 5, with reference to the center line L1, as shown in Figure 7. In this embodiment, the pattern portion C1 is the central portion of the sub-scanning direction X in the first adjustment pattern PT1a. The pattern portion C1 includes the center line L1, where the center line L1 is a line passing through the center of the sub-scanning direction X of the pattern portion C1. However, the center line L1 may be offset forward or backward from the center of the sub-scanning direction X of the pattern portion C1. In this embodiment, the length of the sub-scanning direction X of the pattern portion C1 located forward of the center line L1 is the same as, but may be different from, the length of the sub-scanning direction X of the pattern portion C1 located backward of the center line L1.

[0053] Here, for example, by having the sensor 38 scan along the center line L1 of the first adjustment pattern PT1a, the sensor 38 can scan along the pattern portion C1 of the first adjustment pattern PT1a. Therefore, the sensor movement control unit 67 controls the movement of the sensor head 36 so that the sensor 38 scans along the center line L1 of the first adjustment pattern PT1a. If the center line L1 is calculated using the reference figure F5, the sensor movement control unit 67 controls the movement of the sensor head 36 so that the sensor 38 scans along the pattern portion C1 of the first adjustment pattern PT1a, using the figure center line L2 of the reference figure F5 as a reference. However, the sensor 38 does not need to scan along the center line L1 as long as it scans along at least the pattern portion C1 of the first adjustment pattern PT1a by the sensor movement control unit 67. The sensor 38 may also scan along the pattern portion C1 by scanning a position in front of or behind the center line L1.

[0054] In the above, for example, the center line L1 of the first adjustment pattern PT1a was calculated based on the positions of both ends of the sub-scanning direction X in the first adjustment pattern PT1a, and the sensor 38 scanned the pattern portion C1 with respect to the center line L1. However, it is possible to determine the range of the pattern portion C1 in the first adjustment pattern PT1a based on the position of one end of the sub-scanning direction X in the first adjustment pattern PT1a. Here, one end of the sub-scanning direction X is the front end, but it may also be the rear end. In this case, the storage unit 52 in Figure 3 stores nozzle information indicating the range of the nozzles 40 of the nozzle row 41 used when printing the adjustment pattern PT1 (here, the first adjustment pattern PT1a) printed on the medium 5, and the range of the central nozzle 42 relative to the range of the used nozzles 40. This range of nozzles 40 includes the central nozzle 42. In this case, the position detection unit 63 in Figure 3 controls the transport mechanism 20 and the moving mechanism 30 so that the sensor 38 scans the first figure F1 (or second figure F2) of the first adjustment pattern PT1a in the sub-scanning direction X. At this time, the sensor 38 can detect the position of the boundary in the sub-scanning direction X of the first figure F1 (or second figure F2), thereby detecting the position of the leading end of the first adjustment pattern PT1a.

[0055] The position of the front end of the first adjustment pattern PT1a corresponds to the front nozzle of the nozzle row 41 used when printing one end of the first adjustment pattern PT1a (here, the front end of the first figure F1 or the front end of the second figure F2) in the nozzle information stored in the storage unit 52. The nozzle information indicates the distance between nozzles from the front nozzle to the central nozzle 42 (for example, the front end of the sub-scanning direction X at the central nozzle 42) (here, the distance in the sub-scanning direction X), and the central nozzle length, which is the length of the sub-scanning direction X of the central nozzle 42. Therefore, the range extending backward by the central nozzle length from a position moved backward by the distance between nozzles from the front end of the first adjustment pattern PT1a can be determined as the range of the pattern portion C1 formed by ejection by the central nozzle 42. In this case, the sensor movement control unit 67 only needs to control the movement of the sensor head 36 so that the sensor 38 scans over the pattern portion C1 determined based on the nozzle information stored in the storage unit 52 and the position of one end of the first adjustment pattern PT1a.

[0056] Thus, while the sensor 38 is scanning the pattern portion C1 of the first adjustment pattern PT1a, in step S109 of Figure 4, the reading unit 69 of Figure 3 reads the pattern portion C1 of the first adjustment pattern PT1a by the sensor 38. Here, as shown in Figure 7, at least a portion of the first figure F1 and the second figure F2 of each adjustment set G1 in the first adjustment pattern PT1a are included in the pattern portion C1. Therefore, by reading the pattern portion C1, the reading unit 69 can read the positions of the first figure F1 and the second figure F2 in each adjustment set G1.

[0057] Next, in step S111 of Figure 4, the determination unit 71 of Figure 3 determines an adjustment value V1 for adjusting the ink landing position in bidirectional printing based on the reading result of the pattern portion C1 by the reading unit 69.

[0058] In this embodiment, the determination unit 71 calculates the actual misalignment amount V3 (see Figure 8) for each adjustment set G1 of the first adjustment pattern PT1a printed on the medium 5. This actual misalignment amount V3 is the actual misalignment amount in the main scanning direction Y between the first figure F1 and the second figure F2 in the adjustment set G1. Here, the actual misalignment amount V3 is a positive value, unlike the candidate adjustment value V2. Therefore, even if the first figure F1 is misaligned to the left relative to the second figure F2, the actual misalignment amount V3 will not be negative, but will be an absolute value. Since the actual misalignment amount V3 is the actual misalignment amount between the first figure F1 and the second figure F2 printed on the medium 5, it will differ from the absolute value of the candidate adjustment value V2 when there is a misalignment in the ink landing position in bidirectional printing. This actual misalignment amount V3 can be calculated from the position of the first figure F1 and the position of the second figure F2 read by the reading unit 69.

[0059] Figure 8 is a graph showing the first approximation line L31 and the second approximation line L32. In this way, after calculating the actual deviation amount V3 for each adjustment set G1, the determination unit 71 in Figure 3 calculates the first approximation line L31 and the second approximation line L32 as shown in Figure 8, based on the candidate adjustment value V2 and the actual deviation amount V3 for each adjustment set G1. The first approximation line L31 and the second approximation line L32 are represented by a plane where the horizontal axis is the candidate adjustment value V2 and the vertical axis is the actual deviation amount V3, as shown in Figure 8. The first approximation line L31 is a line in which the actual deviation amount V3 decreases as the candidate adjustment value V2 increases, and the slope is negative. The first approximate line L31 is a line calculated using the candidate adjustment value V2 and the actual deviation amount V3 for adjustment group G1 (in Figure 7, adjustment groups G1a, G1b, and G1c) where the candidate adjustment value V2 is negative, i.e., on the data for the first adjustment pattern PT1a, the first figure F1 is shifted to the left of the second figure F2.

[0060] As shown in Figure 8, the second approximation line L32 is a line in which the actual deviation amount V3 increases as the candidate adjustment value V2 increases, and the slope is positive. The second approximation line L32 is a line calculated from the candidate adjustment value V2 and the actual deviation amount V3 of adjustment group G1 (adjustment groups G1d, G1e, G1f in Figure 7) where the candidate adjustment value V2 is positive, i.e., on the data of the first adjustment pattern PT1a, the first figure F1 is shifted to the right of the second figure F2. The first approximation line L31 and the second approximation line L32 can be expressed by mathematical formulas. Information regarding the first approximation line L31 and the second approximation line L32 is stored in the storage unit 52 in Figure 3.

[0061] After calculating the first approximation line L31 and the second approximation line L32 in this manner, the determination unit 71 determines an adjustment value V1 for adjusting the ink landing position in bidirectional printing. Here, as shown in Figure 8, the first approximation line L31 and the second approximation line L32 intersect at intersection point P1. The determination unit 71 sets the candidate adjustment value V2 at the intersection point P1 of the first approximation line L31 and the second approximation line L32 as the adjustment value V1. The adjustment value V1 determined by the determination unit 71 is stored in the storage unit 52.

[0062] As described above, the sensor 38 reads the first adjustment pattern PT1a, and the adjustment value V1 for ejecting cyan ink is calculated. In this embodiment, the adjustment value V1 is set for each ink color. For example, for the second adjustment pattern PT1b, the adjustment value V1 for ejecting magenta ink can be calculated by executing steps S107, S109, and S111 in order. Similarly, for the third adjustment pattern PT1c and the fourth adjustment pattern PT1d, the adjustment values ​​V1 for ejecting yellow ink and black ink can be calculated by executing steps S107, S109, and S111 in order. Similarly, for the fifth adjustment pattern PT1e, the sixth adjustment pattern PT1f, the seventh adjustment pattern PT1g, and the eighth adjustment pattern PT1h, the adjustment values ​​V1 for ejecting light magenta ink, light cyan ink, light black ink, and orange ink can be calculated by executing steps S107, S109, and S111 in order.

[0063] In this embodiment, adjustments for bidirectional printing are performed based on adjustment values ​​V1 for each color of ink. Here, based on the adjustment values ​​V1, the timing of ink ejection from the ink head 28 during printing when the ink head 28 moves in the return direction Y2 is adjusted. This minimizes the discrepancy in the main scanning direction Y between the ink landing position during printing in the forward direction Y1 and the ink landing position during printing in the return direction Y2.

[0064] In this embodiment, the user can visually confirm the adjustment pattern PT1 printed on the medium 5 by operating the touch panel 13 to transport the medium 5 forward. Subsequently, the user operates the touch panel 13 to switch to a screen for printing the printed image onto the medium 5. At this time, the medium 5 is transported backward to the position where the printing of the adjustment pattern PT1 is completed, or to a position specified by the user. In other words, the medium 5 is automatically transported to the printing start position. Therefore, the user's operational burden can be reduced.

[0065] In this embodiment, as shown in Figure 1, the printer 100 includes a platen 18 that supports the medium 5, an ink head 28 (see Figure 2) that ejects ink onto the medium 5 supported by the platen 18, a sensor head 36, a moving mechanism 30, and a control device 50. The sensor head 36 has a sensor 38 that reads an adjustment pattern PT1 printed on the medium 5, which is an adjustment pattern PT1 (see Figure 5) for adjusting the landing position of ink from the ink head 28 in bidirectional printing. The moving mechanism 30 moves the ink head 28 in the main scanning direction Y during printing and moves the sensor head 36 in the main scanning direction Y when reading the adjustment pattern PT1. As shown in Figure 2, the ink head 28 has a nozzle row 41 in which a plurality of nozzles 40 that eject ink are arranged in the sub-scanning direction X. The nozzle row 41 has a central nozzle 42 located in the central part of the nozzle row 41 in the sub-scanning direction X. Here, the length L11 (see Figure 6) of the sub-scanning direction X of each adjustment pattern PT1 printed on the medium 5 is less than or equal to the length L12 (see Figure 2) of the nozzle row 41. As shown in Figure 3, the control device 50 includes an adjustment pattern printing unit 61, a sensor movement control unit 67, a reading unit 69, and a determination unit 71. As shown in step S101 of Figure 4, the adjustment pattern printing unit 61 prints the adjustment pattern PT1 shown in Figure 5 onto the medium 5 by ejecting ink from the ink head 28 while moving the ink head 28 in the forward direction Y1 and the return direction Y2. As shown in step S107 of Figure 4, the sensor movement control unit 67 controls the movement of the sensor head 36 so that the sensor 38 scans over the pattern portion C1 (see Figure 7) formed by the ink ejected by the central nozzle 42 of the adjustment pattern PT1 printed on the medium 5. As shown in step S109 of Figure 4, the reading unit 69 reads the pattern portion C1 of the adjustment pattern PT1 from the sensor 38 while the sensor head 36 is moving due to the sensor movement control unit 67. As shown in step S111 of Figure 4, the determination unit 71 determines an adjustment value V1 for adjusting the ink landing position in bidirectional printing based on the reading result of the pattern portion C1 by the reading unit 69.

[0066] In this embodiment, the accuracy of the ink landing position of ink ejected from the central nozzle 42 of the nozzle row 41 is better than the accuracy of the ink landing position of ink ejected from the nozzles 40 located at the ends of the nozzle row 41. Therefore, by reading the pattern portion C1 printed by the central nozzle 42, which has better ink landing position accuracy, with the sensor 38, a more accurate adjustment value V1 can be determined from the adjustment pattern PT1 used to adjust the ink landing position from the ink head 28 in bidirectional printing. Thus, the accuracy of adjusting the ink landing position in bidirectional printing can be improved.

[0067] In this embodiment, as shown in Figure 3, the control device 50 includes a position detection unit 63 and a centerline calculation unit 65. The position detection unit 63 detects, for example, the positions of both ends of the sub-scanning direction X of the first adjustment pattern PT1a. The centerline calculation unit 65 calculates a centerline L1 (see Figure 7) passing through the center of the sub-scanning direction X in the first adjustment pattern PT1a based on the positions of both ends of the first adjustment pattern PT1a. The sensor movement control unit 67 in Figure 3 controls the movement of the sensor head 36 so that the sensor 38 scans the pattern portion C1 of the first adjustment pattern PT1a, using the centerline L1 of the first adjustment pattern PT1a as a reference. This makes it possible to easily calculate the centerline L1 of the first adjustment pattern PT1a from the positions of both ends of the sub-scanning direction X of the first adjustment pattern PT1a. Here, using the center line L1 of the first adjustment pattern PT1a as a reference, the sensor 38 scans the pattern portion C1 of the first adjustment pattern PT1a, allowing the sensor 38 to read the pattern portion C1 of the first adjustment pattern PT1a that was printed by the central nozzle 42.

[0068] In this embodiment, the storage unit 52 (see Figure 3) of the control device 50 stores nozzle information indicating the range of the nozzle 40 used when printing the first adjustment pattern PT1a printed on the medium 5. The position detection unit 63 in Figure 3 detects the position of one end (e.g., the front end) of the sub-scanning direction X of the first adjustment pattern PT1a. The sensor movement control unit 67 controls the movement of the sensor head 36 so that the sensor 38 scans the pattern portion C1 of the first adjustment pattern PT1a, which is determined based on the nozzle information and the position of one end of the first adjustment pattern PT1a. In this way, because the range of the nozzle 40 used when printing the first adjustment pattern PT1a is known in advance, the pattern portion C1 of the first adjustment pattern PT1a can be easily calculated by detecting only the position of one end of the sub-scanning direction X of the first adjustment pattern PT1a. In this case, it is not necessary to detect the positions of both ends of the sub-scanning direction X of the first adjustment pattern PT1a, so the detection time can be shortened.

[0069] In this embodiment, as shown in Figure 2, the ink head 28 has multiple nozzle rows 41 with different ink colors ejected from the nozzles 40. As shown in Figure 5, there is an adjustment pattern PT1 for each ink color. The adjustment patterns PT1 for each ink color (here, the first adjustment pattern PT1a to the eighth adjustment pattern PT1h) are arranged to line up in the sub-scanning direction X. Each adjustment pattern PT1 has a forward pattern PT11 and a return pattern PT12. The forward pattern PT11 is a pattern in which multiple first figures F1 printed by ink ejected from at least the central nozzle 42 (see Figure 2) are arranged in the main scanning direction Y when the ink head 28 is moving in the forward direction Y1. The return pattern PT12 is a pattern in which multiple second figures F2 printed by ink ejected from at least the central nozzle 42 (see Figure 2) are arranged in the main scanning direction Y so as to be paired with the first figure F1 when the ink head 28 is moving in the return direction Y2. Here, when the paired first figure F1 and second figure F2 are considered as adjustment pair G1, the position of the first figure F1 relative to the second figure F2 in the main scanning direction Y differs in adjacent adjustment pair G1. As shown in Figure 5, the adjustment pattern printing unit 61 in Figure 3 prints the adjustment pattern PT1 (here, the fourth adjustment pattern PT1d) formed with a predetermined reference color ink from among multiple ink colors, and the reference figure F5 arranged in the main scanning direction Y, onto the medium 5 using the reference color ink. The sensor movement control unit 67 in Figure 3 controls the movement of the sensor head 36 so that the sensor 38 scans the pattern portion C1 of the adjustment pattern PT1, using at least the portion of the reference figure F5 ejected by the central nozzle 42 as a reference.

[0070] Here, the relative position of each adjustment pattern PT1 with respect to the reference figure F5 is unique. Therefore, by identifying the portion of the reference figure F5 discharged by the central nozzle 42, the pattern portion C1 (see Figure 7) of each adjustment pattern PT1 can be uniquely identified.

[0071] In this embodiment, the position detection unit 63 in Figure 3 detects the positions of both ends of the reference figure F5 in the sub-scanning direction X. The centerline calculation unit 65 in Figure 3 calculates the figure centerline L2 that passes through the center of the sub-scanning direction X in the reference figure F5 based on the positions of both ends of the reference figure F5. The sensor movement control unit 67 in Figure 3 controls the movement of the sensor head 36 so that the sensor 38 scans the pattern portion C1 (see Figure 7) of each adjustment pattern PT1, using the figure centerline L2 of the reference figure F5 as a reference. Here, the centerline L1 of each adjustment pattern PT1 is uniquely determined from the figure centerline L2 of the reference figure F5. Therefore, by identifying the figure centerline L2 of the reference figure F5, the pattern portion C1 of each adjustment pattern PT1 can be uniquely identified. In this embodiment, since the pattern portion C1 of each adjustment pattern PT1 can be calculated by detecting only the positions of both ends of the reference figure F5, the detection time can be shortened.

[0072] In this embodiment, the reference color of the ink used to print the reference figure F5 is black. For example, the color of the medium 5 is often a different color from black, such as white. Therefore, by printing the reference figure F5 on the medium 5 with black ink, the position of the reference figure F5 can be easily detected by the sensor 38.

[0073] In this embodiment, as shown in Figure 5, there is an adjustment pattern PT1 for each ink color, and for example, eight adjustment patterns PT1 (here, the first adjustment pattern PT1a to the eighth adjustment pattern PT1h) were arranged in a line in the sub-scanning direction X. However, the number of adjustment patterns PT1 may be one. In this case, the reference figure F5 may be omitted. Here, the position detection unit 63 in Figure 3 may detect, for example, the positions of both ends of one adjustment pattern PT1 in the sub-scanning direction X. The centerline calculation unit 65 in Figure 3 may calculate the centerline L1 of one adjustment pattern PT1 based on the positions of both ends of one adjustment pattern PT1 in the sub-scanning direction X. [Explanation of Symbols]

[0074] 5 Medium 18. Platen (support stand) 28 Inkheads 30 Moving mechanism 36 Sensor Heads 38 sensors 40 nozzles 41 Nozzle Rows 42 Central Nozzle 50 Control device 61 Adjustment pattern printing section 63 Position detection unit 65 Center line calculation section 67 Sensor movement control unit 69 Reading section 71 Decision Section 100 Printers PT1 Adjustment Pattern C1 Pattern section

Claims

1. A support stand for the media, An ink head that ejects ink onto a medium supported on the aforementioned support base, An adjustment pattern printed on a medium, a sensor that reads the adjustment pattern for adjusting the landing position of ink from the ink head in bidirectional printing, A moving mechanism for moving the ink head and the sensor in the main scanning direction, Control device and Equipped with, The ink head has a nozzle row in which a plurality of nozzles for ejecting ink are arranged in the sub-scanning direction, The nozzle row has a central nozzle located in the central portion of the nozzle row in the sub-scanning direction, The length of the adjustment pattern printed on the medium in the sub-scanning direction is less than or equal to the length of the nozzle row. When the direction from one of the main scanning directions to the other is defined as the forward direction, and the direction from the other of the main scanning directions to the one is defined as the return direction, The control device is An adjustment pattern printing unit that prints the adjustment pattern onto a medium by ejecting ink from the ink head while the ink head is moving in the forward and return directions, A sensor movement control unit controls the movement of the sensor so that the sensor scans over the pattern portion of the adjustment pattern printed on the medium, which is formed by the ink ejected by the central nozzle. A reading unit reads the pattern portion of the adjustment pattern using the sensor while the sensor is moving, A determination unit determines an adjustment value for adjusting the ink landing position in bidirectional printing based on the reading result of the pattern portion by the reading unit, A position detection unit for detecting the positions of both ends of the adjustment pattern in the sub-scanning direction, A centerline calculation unit calculates a centerline passing through the center of the sub-scanning direction in the adjustment pattern based on the positions of both ends of the adjustment pattern, Equipped with, A printer in which the sensor movement control unit controls the movement of the sensor so that the sensor scans the pattern portion of the adjustment pattern with respect to the center line of the adjustment pattern.

2. A support base for supporting the medium, An ink head that ejects ink onto a medium supported on the aforementioned support base, An adjustment pattern printed on a medium, a sensor that reads the adjustment pattern for adjusting the landing position of ink from the ink head in bidirectional printing, A moving mechanism for moving the ink head and the sensor in the main scanning direction, Control device and Equipped with, The ink head has a nozzle row in which a plurality of nozzles for ejecting ink are arranged in the sub-scanning direction, The nozzle row has a central nozzle located in the central portion of the nozzle row in the sub-scanning direction, The length of the adjustment pattern printed on the medium in the sub-scanning direction is less than or equal to the length of the nozzle row. When the direction from one of the main scanning directions to the other is defined as the forward direction, and the direction from the other of the main scanning directions to the one is defined as the return direction, The control device is An adjustment pattern printing unit that prints the adjustment pattern onto a medium by ejecting ink from the ink head while the ink head is moving in the forward and return directions, A sensor movement control unit controls the movement of the sensor so that the sensor scans over the pattern portion of the adjustment pattern printed on the medium, which is formed by the ink ejected by the central nozzle. A reading unit reads the pattern portion of the adjustment pattern using the sensor while the sensor is moving, A determination unit determines an adjustment value for adjusting the ink landing position in bidirectional printing based on the reading result of the pattern portion by the reading unit, A storage unit that stores nozzle information indicating the range of the nozzles used when printing the adjustment pattern printed on the medium, A position detection unit for detecting the position of one end of the adjustment pattern in the sub-scanning direction, Equipped with, A printer in which the sensor movement control unit controls the movement of the sensor so that the sensor scans over the pattern portion of the adjustment pattern, which is determined based on the nozzle information and the position of one end of the adjustment pattern.

3. A support base for supporting the medium, An ink head that ejects ink onto a medium supported on the aforementioned support base, An adjustment pattern printed on a medium, a sensor that reads the adjustment pattern for adjusting the landing position of ink from the ink head in bidirectional printing, A moving mechanism for moving the ink head and the sensor in the main scanning direction, Control device and Equipped with, The ink head has a nozzle row in which a plurality of nozzles for ejecting ink are arranged in the sub-scanning direction, The nozzle row has a central nozzle located in the central portion of the nozzle row in the sub-scanning direction, The length of the adjustment pattern printed on the medium in the sub-scanning direction is less than or equal to the length of the nozzle row. When the direction from one of the main scanning directions to the other is defined as the forward direction, and the direction from the other of the main scanning directions to the one is defined as the return direction, The control device is An adjustment pattern printing unit that prints the adjustment pattern onto a medium by ejecting ink from the ink head while the ink head is moving in the forward and return directions, A sensor movement control unit controls the movement of the sensor so that the sensor scans over the pattern portion of the adjustment pattern printed on the medium, which is formed by the ink ejected by the central nozzle. A reading unit reads the pattern portion of the adjustment pattern using the sensor while the sensor is moving, A determination unit determines an adjustment value for adjusting the ink landing position in bidirectional printing based on the reading result of the pattern portion by the reading unit, Equipped with, The ink head has a plurality of nozzle rows, each having a different color of ink ejected from the nozzle. The aforementioned adjustment patterns exist for each ink color. The adjustment patterns for each ink color are arranged so as to be aligned in the sub-scanning direction. The aforementioned adjustment pattern is When the ink head is moving in the forward direction, the first figures printed by ink ejected from at least the central nozzle are arranged in a forward pattern in the main scanning direction, When the ink head is moving in the return direction, the second figure printed by ink ejected from at least the central nozzle is arranged in a return pattern in the main scanning direction in a plurality of parallel arrangements with the first figure, It has, When the pair of the first and second figures are considered as an adjustment set, the position of the first figure relative to the second figure in the main scanning direction is different in adjacent adjustment sets. The adjustment pattern printing unit prints the adjustment pattern, formed with a predetermined reference color ink from among multiple ink colors, and a reference figure arranged in the main scanning direction, onto the medium using the reference color ink. A printer wherein the sensor movement control unit controls the movement of the sensor so that the sensor scans the pattern portion of the adjustment pattern with reference to at least the portion of the reference figure ejected by the central nozzle.

4. The control device is A position detection unit for detecting the positions of both ends of the reference figure in the sub-scanning direction, A centerline calculation unit calculates a figure centerline passing through the center of the sub-scanning direction in the reference figure based on the positions of both ends of the reference figure, Equipped with, The printer according to claim 3, wherein the sensor movement control unit controls the movement of the sensor so that the sensor scans the pattern portion of the adjustment pattern with reference to the center line of the reference figure.

5. The printer according to claim 3 or 4, wherein the reference color is black.

Images