Inkjet printer and method for controlling an inkjet printer

Abstract

To provide an inkjet printer having a bidirectional printing function, which can reduce the workload of an operator even if the height of an inkjet head can be changed. [Solution] In this inkjet printer, when ink is ejected from the inkjet head 3 located at the upper position 3A, the control unit of the inkjet printer controls the timing of ink ejection from the inkjet head 3 so that the deviation between the ink landing position when the carriage moves in the Y1 direction and the ink landing position when the carriage moves in the Y2 direction is corrected based on a first deviation amount S1 and a second deviation amount S2 of the ink landing position that are measured in advance and stored in the control unit.

Description

[Technical Field]

[0001] The present invention relates to an inkjet printer equipped with an inkjet head. The present invention also relates to a control method for such an inkjet printer. [Background technology]

[0002] Conventionally, inkjet printers that print by ejecting ink onto a medium are known (see, for example, Patent Documents 1 and 2). The inkjet printers described in Patent Documents 1 and 2 include an inkjet head that ejects ink, a carriage on which the inkjet head is mounted, a main scanning drive unit that moves the carriage back and forth in the main scanning direction, and a platen located below the carriage. The medium to be printed is placed on the platen.

[0003] The inkjet printer described in Patent Document 1 is an inkjet printer with a so-called bidirectional printing function, in which the inkjet head ejects ink on both the forward pass, in which the carriage moves in one direction in the main scanning direction, and the return pass, in which the carriage moves in the other direction in the main scanning direction, to perform printing. In an inkjet printer that performs bidirectional printing, in order to ensure print quality, it is necessary to correct the deviation between the landing position of ink ejected from the inkjet head on the forward pass and the landing position of ink ejected from the inkjet head on the return pass.

[0004] Therefore, in the inkjet printer described in Patent Document 1, ink is ejected from the inkjet head while the carriage is moved back and forth in the main scanning direction, and a correction pattern is printed to correct the deviation between the ink landing position on the forward pass and the ink landing position on the return pass. Also, in this inkjet printer, the amount of deviation between the ink landing position on the forward pass and the ink landing position on the return pass is calculated based on the detection result of a detection mechanism that detects the density of the correction pattern, and the landing position is corrected based on the calculated amount of deviation.

[0005] The inkjet printer described in Patent Document 2 has a function for adjusting the height of the inkjet head relative to the platen, and in this inkjet printer, the height of the inkjet head relative to the platen is adjustable. This inkjet printer is equipped with a height adjustment means for adjusting the height of the inkjet head relative to the platen. In this inkjet printer, the height of the inkjet head relative to the platen can be adjusted in two stages. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-62491 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-215432 [Overview of the Initiative] [Problem to be solved by the invention]

[0007] The present inventor is developing an inkjet printer with a bidirectional printing function, similar to the inkjet printer described in Patent Document 1. The present inventor decided to add the inkjet head height adjustment function described in Patent Document 2 to the inkjet printer under development. In the inkjet printer under development, even if ink is ejected at the same ejection timing from inkjet heads moving in the same direction, the ink landing position changes depending on the height of the inkjet head.

[0008] Therefore, in this inkjet printer under development, even if the deviation between the ink landing position on the forward pass and the ink landing position on the return pass is corrected when the inkjet head is positioned at a certain height, if the height of the inkjet head changes, it becomes necessary to print the correction pattern again and correct the deviation between the ink landing position on the forward pass and the ink landing position on the return pass based on the detection results of the density of the correction pattern. However, if the deviation between the ink landing position on the forward pass and the ink landing position on the return pass must be corrected in this way when the height of the inkjet head changes, the workload on the inkjet printer operator increases.

[0009] Therefore, an object of the present invention is to provide an inkjet printer with a bidirectional printing function that can reduce the workload of an operator even if the height of the inkjet head can be changed.An object of the present invention is to provide an inkjet printer control method with a bidirectional printing function that can reduce the workload of an operator even if the height of the inkjet head can be changed. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems, an inkjet printer of the present invention is an inkjet printer equipped with an inkjet head that ejects ink, the inkjet printer comprising: a carriage on which the inkjet head is mounted; a carriage drive mechanism that moves the carriage back and forth in a main scanning direction that is perpendicular to the up-down direction; and a control unit that controls the inkjet printer, wherein the carriage comprises a carriage body that holds the inkjet head so that it can be raised and lowered; and a lifting mechanism that raises and lowers the inkjet head relative to the carriage body, wherein, assuming that one side in the main scanning direction is a first direction side and the other side in the main scanning direction opposite to the first direction side is a second direction side, an impact position correction is performed in advance to correct a deviation between an impact position of ink ejected from the inkjet head toward a predetermined printing location when the inkjet head is disposed at a predetermined reference height and the carriage moves in the first direction at a predetermined reference movement speed, and an impact position of ink ejected from the inkjet head toward a printing location when the inkjet head is disposed at the reference height and the carriage moves in the second direction at the reference movement speed, the ink landing position at the printing location after being corrected by the positive value is defined as the corrected landing position; the first deviation amount is defined as the amount of deviation between the first landing position, which is the landing position of ink ejected from the inkjet head toward the printing location when the inkjet head is disposed at a predetermined first height different from the reference height and the carriage is moved in a first direction at a predetermined first movement speed, and the corrected landing position; and the second deviation amount is defined as the amount of deviation between the second landing position, which is the landing position of ink ejected from the inkjet head toward the printing location when the inkjet head is disposed at the first height and the carriage is moved in a second direction at the first movement speed, and the corrected landing position; the first deviation amount and the second deviation amount are measured in advance and stored in a control unit; and when ejecting ink from the inkjet head disposed at the first height while moving the carriage, the control unit controls the timing of ejection of ink from the inkjet head so that the deviation between the ink landing position when the carriage is moved in the first direction and the ink landing position when the carriage is moved in the second direction is corrected based on the first deviation amount and the second deviation amount.

[0011] Furthermore, in order to solve the above problems, the present invention provides an inkjet printer control method comprising an inkjet head that ejects ink, a carriage on which the inkjet head is mounted, and a carriage drive mechanism that reciprocates the carriage in a main scanning direction perpendicular to the vertical direction, wherein the carriage comprises a carriage body that holds the inkjet head so as to be able to move up and down, and a lifting mechanism for moving the inkjet head up and down relative to the carriage body, wherein one side of the main scanning direction is designated as the first direction side, and the other side of the main scanning direction opposite to the first direction side is designated as the second direction side, and the method provides an inkjet printer control method in which an inkjet position correction is performed in advance to correct the difference between the landing position of the ink ejected from the inkjet head toward a predetermined printing location when the inkjet head is positioned at a predetermined reference height and the carriage moves toward the first direction side at a predetermined reference movement speed, and the landing position of the ink ejected from the inkjet head toward the printing location when the inkjet head is positioned at a predetermined reference height and the carriage moves toward the second direction side at a predetermined reference movement speed, and the method provides an inkjet printer control method in which an inkjet position correction is performed in advance to correct the difference between the landing position of the ink ejected from the inkjet head toward the printing location when the inkjet head is positioned at a predetermined reference height and the carriage moves toward the second direction side at a predetermined reference movement speed, and the inkjet position correction The corrected landing position of the ink at the printing area after correction is defined as the corrected landing position. The first deviation is defined as the difference between the first landing position, which is the landing position of the ink ejected from the inkjet head toward the printing area when the inkjet head is positioned at a predetermined first height that is different from the reference height, and the corrected landing position. The second deviation is defined as the difference between the second landing position, which is the landing position of the ink ejected from the inkjet head toward the printing area when the inkjet head is positioned at a first height and the carriage is moved in a second direction at a first movement speed, and the corrected landing position. The first deviation and the second deviation are measured and stored in advance. When ink is ejected from the inkjet head positioned at the first height while the carriage is moving, the timing of ink ejection from the inkjet head is controlled based on the first deviation and the second deviation so that the difference between the landing position of the ink when the carriage is moving in the first direction and the landing position of the ink when the carriage is moving in the second direction is corrected.

[0012] In the present invention, when ink is ejected from an inkjet head positioned at a predetermined first height, the timing of ejecting ink from the inkjet head is controlled based on pre-stored first and second shift amounts so that the shift between the ink landing position when the carriage moves in the first direction and the ink landing position when the carriage moves in the second direction is corrected.

[0013] Therefore, in this invention, when the height of the inkjet head changes, it is possible to automatically correct the deviation of the ink landing position without having to print a correction pattern to correct the deviation between the ink landing position when the carriage moves in the first direction and the ink landing position when the carriage moves in the second direction. Therefore, in this invention, even if the height of the inkjet head can be changed, it is possible to reduce the workload on the operator.

[0014] Furthermore, in the present invention, because the first and second deviation amounts are measured and stored in advance, the first and second deviation amounts can be determined with greater accuracy than when the first and second deviation amounts are calculated based on a formula, for example. Therefore, in the present invention, it is possible to accurately correct the deviation between the ink landing position when the carriage moves in the first direction and the ink landing position when the carriage moves in the second direction.

[0015] Furthermore, in order to solve the above problems, the present invention provides an inkjet printer equipped with an inkjet head that ejects ink, comprising a carriage on which the inkjet head is mounted, a carriage drive mechanism that reciprocates the carriage in a main scanning direction perpendicular to the vertical direction, and a control unit for controlling the inkjet printer, wherein the carriage comprises a carriage body that holds the inkjet head so as to be able to move up and down, and a lifting mechanism for moving the inkjet head up and down relative to the carriage body, wherein one side of the main scanning direction is designated as the first direction side, and the other side of the main scanning direction opposite to the first direction side is designated as the second direction side, and the impact position correction is performed in advance to correct the discrepancy between the impact position of ink ejected from the inkjet head toward a predetermined printing location when the inkjet head is positioned at a predetermined reference height and the carriage moves toward the first direction side at a predetermined reference movement speed, and the impact position correction is performed in advance to correct the discrepancy between the impact position of ink ejected from the inkjet head toward the printing location when the inkjet head is positioned at a predetermined reference height and the carriage moves toward the second direction side at a predetermined reference movement speed, and impact position correction The corrected landing position of the ink at the printing area after correction is defined as the corrected landing position. The first deviation is defined as the difference between the first landing position, which is the landing position of the ink ejected from the inkjet head toward the printing area when the inkjet head is positioned at a predetermined first height that is different from the reference height, and the corrected landing position. The second deviation is defined as the difference between the second landing position, which is the landing position of the ink ejected from the inkjet head toward the printing area when the inkjet head is positioned at a first height and the carriage is moved in a second direction at a first movement speed, and the corrected landing position. The control unit, while ejecting ink from the inkjet head positioned at the first height while moving the carriage, calculates the first deviation and the second deviation based on a predetermined calculation formula, and controls the timing of ink ejection from the inkjet head so as to correct the difference between the landing position of the ink when the carriage is moving in the first direction and the landing position of the ink when the carriage is moving in the second direction, based on the calculated first deviation and second deviation.

[0016] Furthermore, in order to solve the above-mentioned problems, a control method for an inkjet printer of the present invention provides an inkjet printer including an inkjet head that ejects ink, a carriage on which the inkjet head is mounted, and a carriage drive mechanism that moves the carriage back and forth in a main scanning direction perpendicular to the up-down direction, the carriage including a carriage body that holds the inkjet head so that it can be raised and lowered, and an elevating mechanism that raises and lowers the inkjet head relative to the carriage body, wherein one side in the main scanning direction is defined as a first direction side and the other side in the main scanning direction opposite the first direction side is defined as a second direction side, and wherein impact position correction is performed in advance to correct a deviation between a landing position of ink ejected from the inkjet head toward a predetermined printing location when the inkjet head is disposed at a predetermined reference height and the carriage moves in the first direction at a predetermined reference movement speed, and a landing position of ink ejected from the inkjet head toward a printing location when the inkjet head is disposed at the reference height and the carriage moves in the second direction at the reference movement speed, a first deviation amount is a deviation between the corrected landing position and a first landing position, which is a landing position of ink ejected from the inkjet head toward the printing location when the inkjet head is positioned at a predetermined first height different from the reference height and the carriage moves in a first direction at a predetermined first movement speed; and a second deviation amount is a deviation between the corrected landing position and a second landing position, which is a landing position of ink ejected from the inkjet head toward the printing location when the inkjet head is positioned at the first height and the carriage moves in a second direction at the first movement speed. When ink is ejected from the inkjet head positioned at the first height while the carriage is moving, the first deviation amount and the second deviation amount are calculated based on a predetermined calculation formula, and the timing of ejecting ink from the inkjet head is controlled based on the calculated first deviation amount and second deviation amount so as to correct the deviation between the ink landing position when the carriage moves in the first direction and the ink landing position when the carriage moves in the second direction.

[0017] In the present invention, when ink is ejected from an inkjet head positioned at a predetermined first height, a first shift amount and a second shift amount are calculated based on a predetermined calculation formula, and the timing of ink ejection from the inkjet head is controlled based on the calculated first shift amount and second shift amount so that the shift between the ink landing position when the carriage moves in the first direction and the ink landing position when the carriage moves in the second direction is corrected.

[0018] Therefore, in this invention, when the height of the inkjet head changes, it is possible to automatically correct the deviation of the ink landing position without having to print a correction pattern to correct the deviation between the ink landing position when the carriage moves in the first direction and the ink landing position when the carriage moves in the second direction. Therefore, in this invention, even if the height of the inkjet head can be changed, it is possible to reduce the workload on the operator.

[0019] In the present invention, for example, when ejecting ink from an inkjet head positioned at a first height while moving the carriage at a predetermined second movement speed, the control unit controls the timing of ejecting ink from the inkjet head based on the first shift amount, the second shift amount, the first movement speed, and the second movement speed so as to correct the shift between the ink landing position when the carriage moves in the first direction and the ink landing position when the carriage moves in the second direction.

[0020] In the present invention, for example, the lifting mechanism raises and lowers the inkjet head relative to the carriage body between an upper position and a lower position lower than the upper position, and the height of the inkjet head placed in the upper position is either the reference height or the first height, and the height of the inkjet head placed in the lower position is the other of the reference height or the first height. [Effects of the Invention]

[0021] As described above, the present invention makes it possible to reduce the workload of the operator even when the height of the inkjet head can be changed in an inkjet printer having a bidirectional printing function. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic diagram illustrating a configuration of an inkjet printer according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram illustrating the configuration of the inkjet printer shown in FIG. [Figure 3] 2 is a schematic diagram for explaining a method for controlling the ejection timing of ink ejected from the inkjet head shown in FIG. 1. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0024] (Configuration and control method of inkjet printer) Fig. 1 is a schematic diagram illustrating the configuration of an inkjet printer 1 according to an embodiment of the present invention. Fig. 2 is a block diagram illustrating the configuration of the inkjet printer 1 shown in Fig. 1. Fig. 3 is a schematic diagram illustrating a method for controlling the ejection timing of ink ejected from the inkjet head 3 shown in Fig. 1.

[0025] The inkjet printer 1 (hereinafter referred to as "printer 1") of this embodiment is, for example, a commercial inkjet printer that prints on a medium 2 such as paper or fabric. The printer 1 includes an inkjet head 3 (hereinafter referred to as "head 3") that ejects ink toward the medium 2, a carriage 4 on which the head 3 is mounted, a carriage drive mechanism 5 that moves the carriage 4 back and forth in a main scanning direction (Y direction in FIG. 1) that is perpendicular to the up-down direction (vertical direction), a guide rail 6 that guides the carriage 4 in the main scanning direction, and a platen 7 on which the medium 2 is placed.

[0026] Furthermore, the printer 1 includes a control unit 9 for controlling the printer 1. In addition, the printer 1 includes a media transport mechanism for transporting the media 2 in a sub-scanning direction (X direction in Figure 1) that is orthogonal to the vertical direction and the main scanning direction. The media transport mechanism includes a transport roller for transporting the media 2, a roller drive mechanism for driving the transport roller, and a plurality of pinch rollers that are positioned opposite the transport roller and biased toward the transport roller. The roller drive mechanism includes a motor as a drive source. The media 2 is transported while sandwiched between the transport roller and the pinch roller.

[0027] In the following explanation, the main scanning direction (Y direction) will be referred to as the "left-right direction," and the secondary scanning direction (X direction) will be referred to as the "front-back direction." Furthermore, one side of the left-right direction, the Y1 direction side in Figure 1, will be referred to as the "left side," and the opposite side of the left side, the Y2 direction side in Figure 1, will be referred to as the "right side." In this embodiment, the left side (Y1 direction side) is the first direction side, which is one side of the main scanning direction, and the right side (Y2 direction side) is the second direction side, which is the opposite side of the first direction side (i.e., the other side of the main scanning direction). Also, in this embodiment, the left-right direction (Y direction) is the width direction of the medium 2. Furthermore, the up-down direction is the thickness direction of the medium 2 during printing when placed on the platen 7, and the front-back direction (X direction) is the transport direction of the medium 2 moving on the platen 7.

[0028] Printer 1 is a printer with bidirectional printing capabilities. In Printer 1, for example, the print head 3 ejects ink to print on the medium 2 during the forward journey when the carriage 4 moves to the left, and during the return journey when the carriage 4 moves to the right. In Printer 1, the reciprocating motion of the carriage 4 in the left-right direction by the carriage drive mechanism 5 and the transport motion of the medium 2 by the medium transport mechanism are repeated alternately to print on the medium 2.

[0029] The head 3 ejects ink downward. The bottom surface of the head 3 is formed with an ink ejection surface 3a on which a large number of nozzles that eject ink are arranged. The ink ejection surface 3a is formed with a plurality of nozzle rows arranged in the left-right direction (main scanning direction). The nozzle rows are made up of a large number of nozzles arranged in the front-to-rear direction. The head 3 is equipped with a large number of piezoelectric elements (piezo elements) 10 that eject ink from each of the large number of nozzles. The piezoelectric elements 10 are electrically connected to the control unit 9. The platen 7 is positioned below the carriage 4. The medium 2 is placed on the platen 7 during printing.

[0030] The carriage drive mechanism 5 includes, for example, two pulleys, a belt that is stretched over the two pulleys and has a portion fixed to the carriage 4, and a motor that rotates the pulleys. The movement speed of the carriage 4 in the main scanning direction when printing on the medium 2 (i.e., the movement speed of the head 3) varies depending on the ink ejection frequency from the head 3 (i.e., the drive frequency of the piezoelectric element 10) and the resolution of the image printed on the medium 2. Therefore, for example, if the ink ejection frequency from the head 3 is constant, the movement speed of the carriage 4 in the main scanning direction when printing on the medium 2 varies depending on the resolution of the image printed on the medium 2.

[0031] In the following, for simplicity of explanation, it is assumed that the ink ejection frequency from the head 3 is constant. Also, in the following, for simplicity of explanation, it is assumed that printing is performed on the medium 2 at three resolutions: 300 dpi (dots per inch), 600 dpi, and 1200 dpi. In the following explanation, the movement speed of the carriage 4 when printing on the medium 2 at 300 dpi is referred to as "movement speed A," the movement speed of the carriage 4 when printing on the medium 2 at 600 dpi is referred to as "movement speed B," and the movement speed of the carriage 4 when printing on the medium 2 at 1200 dpi is referred to as "movement speed C." Movement speed B is half the speed of movement speed A, and movement speed C is half the speed of movement speed B. It is to be noted that the ink ejection frequency from the head 3 does not have to be constant. Also, printing on the medium 2 may be performed at three or more resolutions.

[0032] In the printer 1, the mounting height of the head 3 relative to the carriage 4 is adjustable. That is, the vertical gap (head gap) between the ink ejection surface 3a of the head 3 and the upper surface of the platen 7 is adjustable. The mounting height of the head 3 relative to the carriage 4 is adjusted depending on the thickness of the medium 2 on which printing is to be performed, etc. The mounting height of the head 3 relative to the carriage 4 may also be adjusted to stabilize the image printed on the medium 2.

[0033] The carriage 4 includes a carriage body 11 that holds the head 3 so that it can be raised and lowered, and an elevator mechanism 12 that raises and lowers the head 3 relative to the carriage body 11. The elevator mechanism 12 includes, for example, a head holding member that holds the head 3, and an eccentric cam that contacts the head holding member to raise and lower it. The eccentric cam is rotatably held by the carriage body 11. The elevator mechanism 12 is, for example, a manual mechanism that does not have a drive source, and the operator of the printer 1 manually rotates the eccentric cam to raise and lower the head holding member. The elevator mechanism 12 may also include a drive source such as a motor for rotating the eccentric cam.

[0034] In this embodiment, the height of the head 3 relative to the carriage body 11 can be adjusted in two stages. The lifting mechanism 12 raises and lowers the head 3 relative to the carriage body 11 between an upper position 3A (see the two-dot chain line in FIG. 1) and a lower position 3B (see the solid line in FIG. 1) that is lower than the upper position 3A. When printing on the medium 2, the head 3 is positioned at either the upper position 3A or the lower position 3B. For example, when the head 3 is positioned at the lower position 3B, the head gap G1 (see FIG. 1) is 1.5 mm, and when the head 3 is positioned at the upper position 3A, the head gap G2 (see FIG. 1) is 2 mm. In this embodiment, the height of the head 3 positioned at the lower position 3B is a predetermined reference height. Furthermore, the height of the head 3 positioned at the upper position 3A is a predetermined first height, and the reference height and the first height are different.

[0035] The control unit 9 recognizes whether the head 3 is positioned at the upper position 3A or the lower position 3B. In other words, the control unit 9 recognizes the height of the head 3. For example, information regarding the height of the head 3 is input to the control unit 9 by the operator of the printer 1 via a predetermined input device, and the control unit 9 recognizes the height of the head 3 based on the input information. Alternatively, the printer 1 is provided with a detection mechanism 13 for detecting the height of the head 3 (see FIG. 2), and the control unit 9 recognizes the height of the head 3 based on the detection result of the detection mechanism 13.

[0036] As described above, the printer 1 has a bidirectional printing function. In this embodiment, for example, when the printer 1 is installed, impact position correction is performed to correct the deviation between the impact position of ink ejected from the head 3 when the carriage 4 moves to the left and the impact position of ink ejected from the head 3 when the carriage 4 moves to the right. In other words, the impact position correction is performed in advance in the printer 1 before printing on the medium 2.

[0037] In the landing position correction of this embodiment, the deviation between the landing position of ink ejected from the head 3 toward a predetermined printing position P (see FIG. 3(A)) when the head 3 is positioned at the lower position 3B (i.e., the head 3 is positioned at the reference height) and the carriage 4 moves to the left at the movement speed B, and the landing position of ink ejected from the head 3 toward the printing position P when the head 3 is positioned at the lower position 3B and the carriage 4 moves to the right at the movement speed B is corrected. In other words, the landing position correction corrects the deviation of the landing position when the head 3 positioned at the lower position 3B is moved at the movement speed B. In the embodiment, the movement speed B is a predetermined reference movement speed.

[0038] In landing position correction, first, the carriage 4 is moved to the left while ink is ejected from the head 3 to print a correction pattern on the test medium 2, and then the carriage 4 is moved to the right while ink is ejected from the head 3 to print a correction pattern on the test medium 2. In addition, for example, an operator visually checks the correction pattern printed on the medium 2, and corrects any deviation between the ink landing position when the carriage 4 moves to the left and the ink landing position when the carriage 4 moves to the right. Alternatively, the printer 1 is equipped with a detection mechanism for detecting the density of the correction pattern printed on the medium 2, and based on the detection results of the detection mechanism, any deviation between the ink landing position when the carriage 4 moves to the left and the ink landing position when the carriage 4 moves to the right is corrected.

[0039] Specifically, in landing position correction, the ejection timing of ink ejected from the head 3 when the carriage 4 moves to the left and the ejection timing of ink ejected from the head 3 when the carriage 4 moves to the right are adjusted so that the ink landing position when the carriage 4 moves to the left and the ink landing position when the carriage 4 moves to the right are approximately the same. Below, the ink landing position at the printing location P after correction by landing position correction is referred to as the corrected landing position IP (see FIG. 3(A)).

[0040] When the head 3, which is positioned at the lower position 3B, is moved to the upper position 3A (i.e., after changing the height of the head 3), and then ink is ejected from the head 3 while the carriage 4 is moved at a movement speed B to print on the medium 2, if the ink is ejected from the head 3 at the ink ejection timing adjusted by the impact position correction, the ink impact position when the carriage 4 moves to the left will be different from the ink impact position when the carriage 4 moves to the right (see Figure 3(B)).

[0041] In order to correct this deviation in the ink landing position, in this embodiment, the following are measured in advance in the printer 1 before printing on the medium 2: a first deviation amount S1, which is the deviation between the first landing position IP1, which is the landing position of ink ejected from the head 3 toward the printing location P when the head 3 is positioned at the upper position 3A (i.e., the head 3 is positioned at the first height) and the carriage 4 moves to the left at the movement speed B, and the corrected landing position IP; and a second deviation amount S2, which is the deviation between the second landing position IP2, which is the landing position of ink ejected from the head 3 toward the printing location P when the head 3 is positioned at the upper position 3A and the carriage 4 moves to the right at the movement speed B, and the corrected landing position IP.

[0042] When measuring the first shift amount S1 and the second shift amount S2, ink is ejected from the head 3 while moving the carriage 4 to print on the medium 2. The measured first shift amount S1 and second shift amount S2 are stored in the control unit 9. That is, the first shift amount S1 and the second shift amount S2 are stored in advance in the control unit 9 before printing on the medium 2. The movement speed B in this embodiment is a predetermined first movement speed, and in this embodiment, the reference movement speed and the first movement speed are the same speed.

[0043] When printing on a medium 2 by ejecting ink from a head 3 positioned at a lower position 3B (i.e., a head 3 positioned at a reference height) while moving the carriage 4 at a movement speed B, the control unit 9 ejects ink from the head 3 at the ink ejection timing adjusted by the landing position correction.

[0044] On the other hand, when printing on the medium 2 by ejecting ink from the head 3 positioned at the upper position 3A (i.e., the head 3 positioned at the first height) while moving the carriage 4, the control unit 9 controls the timing of ejecting ink from the head 3 based on the first shift amount S1 and the second shift amount S2 so as to correct the shift between the ink landing position when the carriage 4 moves to the left and the ink landing position when the carriage 4 moves to the right.

[0045] Specifically, for example, when printing on the medium 2 by ejecting ink from the head 3 located at the upper position 3A while moving the carriage 4 at the movement speed B when the displacement amounts S1 and S2 were measured, the control unit 9 uses the first displacement amount S1 and the second displacement amount S2 as they are to control the ink ejection timing from the head 3 so that the ink landing position when the carriage 4 moves to the left and the ink landing position when the carriage 4 moves to the right are approximately the same. More specifically, the control unit 9 advances the ink ejection timing from the head 3 so that the ink landing position when the carriage 4 moves to the left and the ink landing position when the carriage 4 moves to the right are approximately the same (see Figure 3(C)). In this case, the movement speed B is the second movement speed.

[0046] On the other hand, if the movement speed of carriage 4 changes, the ink's landing position will change even if ink is ejected from head 3 at the same ejection timing. Therefore, when printing on medium 2 by ejecting ink from head 3 located at the upper position 3A while carriage 4 is moving at a different movement speed than movement speed B, if the ink ejection timing from head 3 is controlled using the same first shift amount S1 and second shift amount S2, the ink's landing position when carriage 4 moves to the left will be different from the ink's landing position when carriage 4 moves to the right.

[0047] For example, when printing on the medium 2 by ejecting ink from the head 3 located at the upper position 3A while moving the carriage 4 at a moving speed A, the control unit 9 uses a corrected displacement obtained by multiplying the first displacement S1 and the second displacement S2 by the ratio of the moving speed A to the moving speed B (i.e., moving speed A / moving speed B) when measuring the displacement amounts S1 and S2, to control the ink ejection timing from the head 3 so that the ink landing position when the carriage 4 moves to the left and the ink landing position when the carriage 4 moves to the right are approximately the same. In this case, the moving speed A is the second moving speed.

[0048] Furthermore, for example, when printing on the medium 2 by ejecting ink from the head 3 located at the upper position 3A while moving the carriage 4 at the movement speed C, the control unit 9 controls the timing of ejecting ink from the head 3 so that the ink landing position when the carriage 4 moves to the left and the ink landing position when the carriage 4 moves to the right approximately coincide, using a corrected deviation amount obtained by multiplying the first deviation amount S1 and the second deviation amount S2 by the ratio of the movement speed C to the movement speed B when the deviation amounts S1 and S2 were measured (i.e., movement speed C / movement speed B). In this case, the movement speed C is the second movement speed.

[0049] In this way, when ejecting ink from the head 3 positioned at the first height while moving the carriage 4 at the second movement speed, the control unit 9 controls the timing of ejecting ink from the head 3 based on the first shift amount S1, the second shift amount S2, the movement speed B which is the first movement speed, and the second movement speed so that the deviation between the ink landing position when the carriage 4 moves to the left and the ink landing position when the carriage 4 moves to the right is corrected.

[0050] When printing on the medium 2 by ejecting ink from the head 3 positioned at the lower position 3B while moving the carriage 4 at the movement speed A or the movement speed C, the control unit 9 corrects the ink ejection timing adjusted by the impact position correction using a predetermined correction method, and ejects ink from the head 3 at the corrected ink ejection timing.

[0051] (Main effect of this form) As described above, in this embodiment, landing position correction is performed in advance to correct the deviation between the landing position of ink ejected from head 3 toward printing location P when head 3 is positioned at the reference height and carriage 4 moves to the left at movement speed B, and the landing position of ink ejected from head 3 toward printing location P when head 3 is positioned at the reference height and carriage 4 moves to the right at movement speed B.

[0052] Furthermore, if the corrected impact position of the ink at the printing location P after correction is defined as the corrected impact position IP, then in this embodiment, the first deviation amount S1 is the amount of deviation between the first impact position IP1, which is the impact position of the ink ejected from the head 3 toward the printing location P when the head 3 is positioned at a first height and the carriage 4 moves to the left at a movement speed B, and the corrected impact position IP. The second deviation amount S2 is the amount of deviation between the second impact position IP2, which is the impact position of the ink ejected from the head 3 toward the printing location P when the head 3 is positioned at a first height and the carriage 4 moves to the right at a movement speed B, and the corrected impact position IP. These values ​​are measured in advance before printing on the medium 2, and the first deviation amount S1 and the second deviation amount S2 are stored in the control unit 9 in advance.

[0053] Furthermore, in this embodiment, when the control unit 9 moves the carriage 4 and ejects ink from the head 3 positioned at a first height to print on the medium 2, it controls the timing of ink ejection from the head 3 based on pre-stored first displacement amount S1 and second displacement amount S2, so as to correct the difference between the ink landing position when the carriage 4 moves to the left and the ink landing position when the carriage 4 moves to the right.

[0054] Therefore, in this configuration, when the height of the head 3 changes from the reference height to the first height, a correction pattern is printed, and the discrepancy between the ink impact position when the carriage 4 moves to the left and the ink impact position when the carriage 4 moves to the right is not corrected automatically. Thus, in this configuration, even though the height of the head 3 can be changed, the workload on the operator can be reduced.

[0055] (Example of change in ink ejection timing control) In the above-described embodiment, the first shift amount S1 and the second shift amount S2 do not have to be measured in advance before printing on the medium 2. In this case, when printing on the medium 2 by ejecting ink from the head 3 located at the upper position 3A while moving the carriage 4, the control unit 9 calculates the first shift amount S1 and the second shift amount S2 based on a predetermined calculation formula, and controls the timing of ejecting ink from the head 3 based on the calculated first shift amount S1 and second shift amount S2 so as to correct the deviation between the ink landing position when the carriage 4 moves to the left and the ink landing position when the carriage 4 moves to the right.

[0056] If the difference between the time it takes for ink ejected from the head 3 located at the upper position 3A to land on the medium 2 and the time it takes for ink ejected from the head 3 located at the lower position 3B to land on the medium 2 is defined as the impact time difference, the first deviation amount S1 and the second deviation amount S2 are calculated, for example, by multiplying the moving speed of the carriage 4 by the impact time difference. Even in this modified example, the same effect as in the above-described embodiment can be obtained.

[0057] Note that the first deviation amount S1 and the second deviation amount S2 can be determined more accurately by measuring them rather than calculating them based on a formula. Therefore, the above-described embodiment makes it possible to accurately correct the deviation between the ink landing position when the carriage 4 moves to the left and the ink landing position when the carriage 4 moves to the right.

[0058] (Other embodiments) The above-described embodiment is one example of a preferred embodiment of the present invention, but the present invention is not limited to this embodiment and various modifications can be made without departing from the spirit of the present invention.

[0059] In the above-described embodiment, the height of the head 3 relative to the carriage body 11 may be adjustable in three or more stages. For example, the height of the head 3 relative to the carriage body 11 may be adjustable in three stages. In this case, for example, when printing on the medium 2, the head 3 is positioned at the upper position 3A, the lower position 3B, or an intermediate position between the upper position 3A and the lower position 3B. The control unit 9 recognizes whether the head 3 is positioned at the upper position 3A, the lower position 3B, or the intermediate position. In this case, in addition to the first deviation amount S1 and the second deviation amount S2 when the head 3 is positioned at the upper position 3A, the first deviation amount S1 and the second deviation amount S2 when the head 3 is positioned at the intermediate position are measured in advance and stored in the control unit 9.

[0060] In this case, when printing on the medium 2 by ejecting ink from the head 3 positioned at the upper position 3A while moving the carriage 4, and when printing on the medium 2 by ejecting ink from the head 3 positioned at an intermediate position while moving the carriage 4, the control unit 9 controls the timing of ink ejection from the head 3 based on the first shift amount S1 and the second shift amount S2 so as to correct the deviation between the ink landing position when the carriage 4 moves to the left and the ink landing position when the carriage 4 moves to the right. In this case, the height of the head 3 positioned at the upper position 3A and the height of the head 3 positioned at the intermediate position are the first heights. In other words, in the above-mentioned embodiment, there may be multiple first heights.

[0061] In the embodiment described above, the landing position correction may correct a deviation in landing position when the head 3 disposed at the upper position 3A is moved. In this case, a first deviation amount S1, which is the deviation amount between the corrected landing position IP and a first landing position IP1, which is the landing position of ink ejected from the head 3 disposed at the lower position 3B toward the printing position P, and a second deviation amount S2, which is the deviation amount between the corrected landing position IP and a second landing position IP2, which is the landing position of ink ejected from the head 3 disposed at the lower position 3B toward the printing position P, are measured in advance before printing on the medium 2 and stored in the control unit 9.

[0062] In this case, when printing on the medium 2 by ejecting ink from the head 3 located at the lower position 3B while moving the carriage 4, the control unit 9 controls the timing of ejecting ink from the head 3 based on the first shift amount S1 and the second shift amount S2 so as to correct the shift between the ink landing position when the carriage 4 moves to the left and the ink landing position when the carriage 4 moves to the right. In this case, the height of the head 3 located at the upper position 3A is the reference height, and the height of the head 3 located at the lower position 3B is the first height.

[0063] In the embodiment described above, in the impact position correction, the carriage 4 may be moved at the movement speed A or the movement speed C. In this case, the movement speed A or the movement speed C of the carriage 4 in the impact position correction is the reference movement speed, and the reference movement speed and the first movement speed are different speeds. Also, in the embodiment described above, when measuring the first shift amount S1 and the second shift amount S2, the carriage 4 may be moved at the movement speed A or the movement speed C. In this case, the movement speed A or the movement speed C of the carriage 4 when measuring the first shift amount S1 and the second shift amount S2 is the first movement speed, and the reference movement speed and the first movement speed are different speeds.

[0064] In the above-described embodiment, the printer 1 may be provided with, instead of the platen 7 and the medium transport mechanism, a table on which the medium 2 is placed and a Y-bar or a moving mechanism to which the guide rail 6 is fixed that moves the table in the forward and backward directions. [Explanation of symbols]

[0065] 1. Printer (inkjet printer) 3 heads (inkjet heads) 3A Upper position 3B Lower position 4 carriages 5. Carriage drive mechanism 9 Control Unit 11 Carriage body 12 Lifting mechanism IP-corrected impact point IP1 First Impact Point IP2 Second Impact Point P Printing location S1 First displacement C2 Second displacement Y Main scanning direction Y1 1st direction side Y2 Second direction

Claims

1. In an inkjet printer equipped with an inkjet head that ejects ink, a carriage on which the inkjet head is mounted, a carriage drive mechanism for reciprocating the carriage in a main scanning direction perpendicular to the up-down direction, and a control unit for controlling the inkjet printer; the carriage includes a carriage body that holds the inkjet head so that the inkjet head can be raised and lowered, and a lifting mechanism that raises and lowers the inkjet head relative to the carriage body; If one side in the main scanning direction is defined as a first direction side, and the other side in the main scanning direction opposite to the first direction side is defined as a second direction side, then: an impact position correction is performed in advance to correct a deviation between an impact position of ink ejected from the inkjet head toward a predetermined printing location when the inkjet head is disposed at a predetermined reference height and the carriage moves in the first direction at a predetermined reference movement speed, and an impact position of ink ejected from the inkjet head toward the printing location when the inkjet head is disposed at the reference height and the carriage moves in the second direction at the reference movement speed; a post-correction landing position is the landing position of ink at the printing location after the landing position correction, a first deviation amount is the amount of deviation between a first landing position, which is the landing position of ink ejected from the inkjet head toward the printing location when the inkjet head is disposed at a predetermined first height different from the reference height and the carriage moves in the first direction at a predetermined first movement speed, and the post-correction landing position, and a second deviation amount is the amount of deviation between a second landing position, which is the landing position of ink ejected from the inkjet head toward the printing location when the inkjet head is disposed at the first height and the carriage moves in the second direction at the first movement speed, and the post-correction landing position. an ink jet printer characterized in that the first deviation amount and the second deviation amount are measured in advance and stored in the control unit, and when ink is ejected from the ink jet head positioned at the first height while the carriage is moved, the control unit controls the timing of ink ejection from the ink jet head based on the first deviation amount and the second deviation amount so as to correct a deviation between the ink landing position when the carriage moves in the first direction and the ink landing position when the carriage moves in the second direction.

2. In an inkjet printer equipped with an inkjet head that ejects ink, a carriage on which the inkjet head is mounted, a carriage drive mechanism for reciprocating the carriage in a main scanning direction perpendicular to the up-down direction, and a control unit for controlling the inkjet printer; the carriage includes a carriage body that holds the inkjet head so that the inkjet head can be raised and lowered, and a lifting mechanism that raises and lowers the inkjet head relative to the carriage body; If one side in the main scanning direction is defined as a first direction side, and the other side in the main scanning direction opposite to the first direction side is defined as a second direction side, then: an impact position correction is performed in advance to correct a deviation between an impact position of ink ejected from the inkjet head toward a predetermined printing location when the inkjet head is disposed at a predetermined reference height and the carriage moves in the first direction at a predetermined reference movement speed, and an impact position of ink ejected from the inkjet head toward the printing location when the inkjet head is disposed at the reference height and the carriage moves in the second direction at the reference movement speed; a post-correction landing position is the landing position of ink at the printing location after the landing position correction, a first deviation amount is the amount of deviation between a first landing position, which is the landing position of ink ejected from the inkjet head toward the printing location when the inkjet head is disposed at a predetermined first height different from the reference height and the carriage moves in the first direction at a predetermined first movement speed, and the post-correction landing position, and a second deviation amount is the amount of deviation between a second landing position, which is the landing position of ink ejected from the inkjet head toward the printing location when the inkjet head is disposed at the first height and the carriage moves in the second direction at the first movement speed, and the post-correction landing position. the control unit, when ejecting ink from the inkjet head positioned at the first height while moving the carriage, calculates the first deviation amount and the second deviation amount based on a predetermined calculation formula, and controls the ejection timing of ink from the inkjet head based on the calculated first deviation amount and second deviation amount so as to correct a deviation between the ink landing position when the carriage moves in the first direction and the ink landing position when the carriage moves in the second direction.

3. 3. The inkjet printer according to claim 1, wherein, when ejecting ink from the inkjet head positioned at the first height while moving the carriage at a predetermined second movement speed, the control unit controls the timing of ejecting ink from the inkjet head based on the first deviation amount, the second deviation amount, the first movement speed, and the second movement speed so as to correct a deviation between an ink landing position when the carriage moves in the first direction and an ink landing position when the carriage moves in the second direction.

4. the lifting mechanism lifts and lowers the inkjet head relative to the carriage body between an upper position and a lower position that is lower than the upper position; the inkjet head disposed at the upper position is at either the reference height or the first height; 3. The inkjet printer according to claim 1, wherein the height of the inkjet head disposed in the lower position is the other of the reference height and the first height.

5. an inkjet head that ejects ink; a carriage on which the inkjet head is mounted; and a carriage drive mechanism that reciprocates the carriage in a main scanning direction that is perpendicular to the up-down direction; the carriage includes a carriage body that holds the inkjet head so that the inkjet head can be raised and lowered, and a lifting mechanism that raises and lowers the inkjet head relative to the carriage body; If one side in the main scanning direction is defined as a first direction side, and the other side in the main scanning direction opposite to the first direction side is defined as a second direction side, then: a control method for an inkjet printer in which a landing position correction is performed in advance to correct a deviation between a landing position of ink ejected from the inkjet head toward a predetermined printing location when the inkjet head is disposed at a predetermined reference height and the carriage moves in the first direction at a predetermined reference movement speed, and a landing position of ink ejected from the inkjet head toward the printing location when the inkjet head is disposed at the reference height and the carriage moves in the second direction at the reference movement speed, a post-correction landing position is the landing position of ink at the printing location after the landing position correction, a first deviation amount is the amount of deviation between a first landing position, which is the landing position of ink ejected from the inkjet head toward the printing location when the inkjet head is disposed at a predetermined first height different from the reference height and the carriage moves in the first direction at a predetermined first movement speed, and the post-correction landing position, and a second deviation amount is the amount of deviation between a second landing position, which is the landing position of ink ejected from the inkjet head toward the printing location when the inkjet head is disposed at the first height and the carriage moves in the second direction at the first movement speed, and the post-correction landing position. a control method for an inkjet printer, characterized in that the first deviation amount and the second deviation amount are measured and stored in advance, and when ink is ejected from the inkjet head positioned at the first height while the carriage is moved, the timing of ink ejection from the inkjet head is controlled based on the first deviation amount and the second deviation amount so as to correct a deviation between the ink landing position when the carriage moves in the first direction and the ink landing position when the carriage moves in the second direction.

6. an inkjet head that ejects ink; a carriage on which the inkjet head is mounted; and a carriage drive mechanism that reciprocates the carriage in a main scanning direction that is perpendicular to the up-down direction; the carriage includes a carriage body that holds the inkjet head so that the inkjet head can be raised and lowered, and a lifting mechanism that raises and lowers the inkjet head relative to the carriage body; If one side in the main scanning direction is defined as a first direction side, and the other side in the main scanning direction opposite to the first direction side is defined as a second direction side, then: a control method for an inkjet printer in which a landing position correction is performed in advance to correct a deviation between a landing position of ink ejected from the inkjet head toward a predetermined printing location when the inkjet head is disposed at a predetermined reference height and the carriage moves in the first direction at a predetermined reference movement speed, and a landing position of ink ejected from the inkjet head toward the printing location when the inkjet head is disposed at the reference height and the carriage moves in the second direction at the reference movement speed, a post-correction landing position is the landing position of ink at the printing location after the landing position correction, a first deviation amount is the amount of deviation between a first landing position, which is the landing position of ink ejected from the inkjet head toward the printing location when the inkjet head is disposed at a predetermined first height different from the reference height and the carriage moves in the first direction at a predetermined first movement speed, and the post-correction landing position, and a second deviation amount is the amount of deviation between a second landing position, which is the landing position of ink ejected from the inkjet head toward the printing location when the inkjet head is disposed at the first height and the carriage moves in the second direction at the first movement speed, and the post-correction landing position. a control method for an inkjet printer, the control method comprising: calculating the first deviation amount and the second deviation amount based on a predetermined calculation formula when ink is ejected from the inkjet head positioned at the first height while the carriage is moved; and controlling the timing of ink ejection from the inkjet head based on the calculated first deviation amount and second deviation amount so as to correct a deviation between the ink landing position when the carriage moves in the first direction and the ink landing position when the carriage moves in the second direction.

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