Inkjet printer and method for controlling an inkjet printer

Abstract

To provide an inkjet printer in which flushing boxes are installed on both sides of a platen in the main scanning direction, and which can efficiently perform a flushing operation when printing is performed by moving an inkjet head by logical seek. [Solution] In this inkjet printer, before printing images P11 and P13, which are one-pass printed images printed by an inkjet head 3 moving in the Y1 direction, a determination is made as to whether or not a flushing operation should be performed on a flushing box 15 after printing images P11 and P13, depending on the print end position of images P11 and P13, and before printing image P12, which is a one-pass printed image printed by an inkjet head 3 moving in the Y2 direction, a determination is made as to whether or not a flushing operation should be performed on a flushing box 16 after printing image P12, depending on the print end position of image P12.

Description

[Technical Field]

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

[0002] Conventionally, inkjet printers have been known that include a head (inkjet head) that ejects ink toward paper, a carriage on which the head is mounted, and a paper feed mechanism that transports the paper (see, for example, Patent Document 1). The inkjet printer described in Patent Document 1 performs desired printing on paper by alternately repeating one-pass printing, in which ink is ejected from the head while the carriage is moved in the main scanning direction, and paper transport, in which the paper is transported a predetermined amount in the sub-scanning direction.

[0003] In the inkjet printer described in Patent Document 1, the head is moved by logical seek, which moves the head in the main scanning direction according to the print start and end positions of one pass of printing, so that the amount of head movement when one pass of printing is repeated is minimized. By moving the head by logical seek, this inkjet printer can reduce the head movement time, and as a result, the time it takes to print on paper.

[0004] Also, conventionally, there is known an inkjet printer that includes an inkjet head that ejects ink toward a medium and a carriage on which the inkjet head is mounted (see, for example, Patent Document 2). In the inkjet printer described in Patent Document 2, a flushing operation is performed as a maintenance operation for the inkjet head, in which ink is forcibly ejected from the inkjet head. The flushing operation is performed to prevent the ink from thickening or drying out near the nozzles of the inkjet head.

[0005] In the inkjet printer described in Patent Document 2, for example, a flushing box for receiving ink during a flushing operation is disposed midway along the path of movement of the inkjet head in the main scanning direction, and the flushing operation is performed when the inkjet head passes over the flushing box. When the flushing operation is performed while the inkjet head is moving in the main scanning direction, it is possible to shorten the printing time on the medium while ensuring the print quality of the medium. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-51098 [Patent Document 2] Japanese Patent Application Publication No. 2020-110989 Summary of the Invention [Problem to be solved by the invention]

[0007] The inventors of the present application are developing an inkjet printer that includes an inkjet head that ejects ink, a carriage on which the inkjet head is mounted, a carriage drive mechanism that moves the carriage in the main scanning direction, and a platen or table that is disposed below the inkjet head. The inventors of the present application are considering adding a logical seek function to the printer under development, and moving the inkjet head by logical seek to perform printing.

[0008] Furthermore, the inventors of the present application are considering installing flushing boxes on both sides of the platen or table in the main scanning direction in an inkjet printer currently under development, so that when printing is performed by moving the inkjet head using logical seek, a flushing operation can be performed while the inkjet head is moving in the main scanning direction. In this inkjet printer currently under development, when printing is performed by moving the inkjet head using logical seek, it is preferable that the flushing operation be performed efficiently in order to further shorten the printing time while maintaining print quality.

[0009] Therefore, an object of the present invention is to provide an inkjet printer in which flushing boxes are provided on both sides of a platen or table arranged below the inkjet head in the main scanning direction, and which is capable of efficiently performing a flushing operation when printing by moving the inkjet head using logical seek.Another object of the present invention is to provide an inkjet printer control method in which flushing boxes are provided on both sides of a platen or table arranged below the inkjet head in the main scanning direction, and which is capable of efficiently performing a flushing operation when printing by moving the inkjet head using logical seek. [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 having 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; a platen or table that is arranged below the inkjet head; first and second flushing boxes that are arranged below the inkjet head and that receive ink ejected from the inkjet head by a flushing operation; and a control unit that controls the inkjet printer, wherein one side of the main scanning direction is defined as a first direction side, and the other side of the main scanning direction opposite the first direction side is defined as a second direction side, the first flushing box is arranged on the first direction side of the platen or table, and the second flushing box is arranged on the second direction side of the platen or table, and the inkjet head that ejects ink toward the first flushing box or the second flushing box by a flushing operation moves in the main scanning direction together with the carriage, and the carriage in the main scanning direction is moved by the carriage. An image printed by the inkjet head in one pass of the carriage is defined as a one-pass print image, a one-pass print image printed by the inkjet head moving in a first direction together with the carriage is defined as a first print image, a one-pass print image printed by the inkjet head moving in a second direction together with the carriage is defined as a second print image, a flushing operation performed on the first flushing box is defined as a first flushing operation, and a flushing operation performed on the second flushing box is defined as a second flushing operation.The control unit receives print data before printing begins, moves the inkjet head in the main scanning direction by logical seek, which moves the inkjet head in the main scanning direction together with the carriage according to the print start position and print end position of the one-pass print image, and determines, before printing the first print image, whether to perform the first flushing operation after printing the first print image according to the print end position of the first print image, and determines, before printing the second print image, whether to perform the second flushing operation after printing the second print image according to the print end position of the second print image.

[0011] Further, in order to solve the above-mentioned problems, a control method for an inkjet printer of the present invention includes an inkjet head that ejects ink, 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, a platen or table that is arranged below the inkjet head, and a first flushing box and a second flushing box that are arranged below the inkjet head and receive ink ejected from the inkjet head by a flushing operation, 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, the first flushing box is arranged on the first direction side of the platen or table, and the second flushing box is arranged on the second direction side of the platen or table, and the inkjet head that ejects ink toward the first flushing box or the second flushing box by a flushing operation moves in the main scanning direction together with the carriage, and printing is performed by the inkjet head in one pass of the carriage in the main scanning direction. a first print image printed by the inkjet head moving in the first direction together with the carriage according to a print start position and a print end position of the first print image; a control method for an inkjet printer in which print data is input before printing starts, the method comprising a determination step of determining whether to perform a flushing operation on a first flushing box or a second flushing box; a first print image is a one-pass print image printed by the inkjet head moving in the first direction together with the carriage; a second print image is a one-pass print image printed by the inkjet head moving in the second direction together with the carriage; the first flushing operation is a flushing operation performed on the first flushing box; and a second flushing operation is a flushing operation performed on the second flushing box;Whether or not to perform the second flushing operation after printing the second print image is determined based on the printing end position of the second print image.

[0012] In the inkjet printer of the present invention, an image printed by the inkjet head in one pass of the carriage in the main scanning direction is defined as a one-pass printed image, a one-pass printed image printed by the inkjet head moving in the first direction, which is one side of the main scanning direction, is defined as a first printed image, a one-pass printed image printed by the inkjet head moving in the second direction, which is the other side of the main scanning direction, is defined as a second printed image, a flushing operation performed on the first flushing box is defined as a first flushing operation, and a flushing operation performed on the second flushing box is defined as a second flushing operation, and before printing the first printed image, the control unit determines whether to perform the first flushing operation after printing the first printed image depending on the printing end position of the first printed image, and before printing the second printed image, determines whether to perform the second flushing operation after printing the second printed image depending on the printing end position of the second printed image.

[0013] In addition, the inkjet printer control method of the present invention includes a judgment step for judging and deciding whether to perform a flushing operation on the first flushing box or the second flushing box, and in the judgment step, before printing the first print image, it is judged whether to perform the first flushing operation after printing the first print image depending on the printing end position of the first print image, and before printing the second print image, it is judged whether to perform the second flushing operation after printing the second print image depending on the printing end position of the second print image.

[0014] Therefore, in the present invention, if the printing end position of the first print image is close to the first flushing box, the first flushing operation is performed after printing the first print image, and if the printing end position of the first print image is far from the first flushing box, the first flushing operation is not performed after printing the first print image. Furthermore, in the present invention, if the printing end position of the second print image is close to the second flushing box, the second flushing operation is performed after printing the second print image, and if the printing end position of the second print image is far from the second flushing box, the second flushing operation is not performed after printing the second print image. Therefore, in the present invention, flushing operations can be performed efficiently when printing by moving the inkjet head using logical seek.

[0015] In the present invention, it is preferable that if the printing end position of the first print image is on the first direction side of the center of the platen or table in the main scanning direction, a first flushing operation is performed unconditionally or when certain conditions are met after printing the first print image, and if the printing end position of the second print image is on the second direction side of the center of the platen or table in the main scanning direction, a second flushing operation is performed unconditionally or when certain conditions are met after printing the second print image. With this configuration, it is determined whether to perform the flushing operation on the first flushing box or the second flushing box based on the center of the platen or table in the main scanning direction, making it possible to appropriately determine whether to perform the flushing operation on the first flushing box or the second flushing box.

[0016] In the present invention, the number of times the carriage performs one pass without a flushing operation after printing starts or after the previous flushing operation has been performed is defined as the number of non-flushing operations, and the distance the carriage operates without a flushing operation after printing starts or after the previous flushing operation has been performed is defined as the non-flushing operation distance.In this case, the judgment step determines whether or not to perform a first flushing operation after printing the first print image based on the printing end position of the first print image and the number of non-flushing operations or the non-flushing operation distance, and determines whether or not to perform a second flushing operation after printing the second print image based on the printing end position of the second print image and the number of non-flushing operations or the non-flushing operation distance.If the number of non-flushing operations is less than a predetermined reference number, or if the non-flushing operation distance is less than a predetermined reference distance, it is preferable that the first flushing operation is not performed after printing the first print image, and the second flushing operation is not performed after printing the second print image. With this configuration, for example, even when ink is used that allows print quality to be maintained even if the frequency of flushing operations is reduced, it is possible to perform flushing operations efficiently.

[0017] In the inkjet printer control method of the present invention, when a next one-pass print image is printed after a first-pass print image is printed, it is preferable to include a second determination step of determining whether to perform a flushing operation on the first flushing box or the second flushing box before printing the next first-pass print image, depending on the pre-printing travel distance, which is the distance in the main scanning direction between the print start position of the next one-pass print image and the current position of the inkjet head. This configuration makes it possible to perform a flushing operation before printing the next one-pass print image when the pre-printing travel distance is long and ink viscosity is likely to increase, and not to perform a flushing operation before printing the next one-pass print image when the pre-printing travel distance is short and ink viscosity is unlikely to increase. This makes it possible to perform a flushing operation more efficiently.

[0018] In the present invention, for example, if the pre-printing movement distance is longer than half the width of the platen or table in the main scanning direction, and certain conditions are met, a flushing operation is performed on the first flushing box or the second flushing box before printing the next first pass print image.

[0019] In the present invention, in the second judgment step, it is preferable to determine whether to perform a flushing operation on the first flushing box or the second flushing box before printing the next first-pass print image depending on the pre-printing movement distance and the current position of the inkjet head, and if the printing of the next one-pass print image is the printing of the first print image, and if the current position of the inkjet head is on the second direction side of the second flushing box, not to perform the second flushing operation before printing the next first print image, and if the printing of the next one-pass print image is the printing of the second print image, and if the current position of the inkjet head is on the first direction side of the first flushing box, not to perform the first flushing operation before printing the next second print image.

[0020] When the printing of the next one-pass print image is the printing of the first print image and the current position of the inkjet head is on the second direction side of the second flushing box, or when the printing of the next one-pass print image is the printing of the second print image and the current position of the inkjet head is on the first direction side of the first flushing box, it is assumed that a flushing operation is being performed just before the inkjet head moves to its current position, and thus this configuration makes it possible to prevent excessive flushing operations from being performed.

[0021] In this invention, the number of one-pass carriage operations without a flushing operation since the start of printing or the previous flushing operation is defined as the number of non-flushing operations, and the distance traveled by the carriage without a flushing operation since the start of printing or the previous flushing operation is defined as the non-flushing operation distance. In the second determination step, it is determined whether to perform a flushing operation on the first flushing box or the second flushing box before printing the next first-pass print image based on the pre-printing travel distance and the number of non-flushing operations or the non-flushing operation distance. If the number of non-flushing operations is equal to or less than a predetermined reference number, or if the non-flushing operation distance is equal to or less than a predetermined reference distance, and certain conditions are met, it is preferable that a flushing operation not be performed before printing the next first-pass print image. This configuration enables efficient flushing operations when print quality can be maintained even if the frequency of flushing operations is reduced. [Effects of the Invention]

[0022] As described above, the present invention makes it possible to efficiently perform flushing operations when printing by moving the inkjet head using logical seek in an inkjet printer in which flushing boxes are installed on both sides in the main scanning direction of a platen or table located below the inkjet head. [Brief explanation of the drawings]

[0023] [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] 1. FIG. 4 is a schematic diagram for explaining the timing and location of a flushing operation that is performed when bidirectional printing is performed with the logical seek function turned on in the inkjet printer shown in FIG. [Figure 4]1. FIG. 4 is a schematic diagram for explaining the timing and location of a flushing operation that is performed when bidirectional printing is performed with the logical seek function turned on in the inkjet printer shown in FIG. [Figure 5] 1. FIG. 4 is a schematic diagram for explaining the timing and location of a flushing operation that is performed when bidirectional printing is performed with the logical seek function turned on in the inkjet printer shown in FIG. [Figure 6] 1. FIG. 4 is a schematic diagram for explaining the timing and location of a flushing operation that is performed when bidirectional printing is performed with the logical seek function turned on in the inkjet printer shown in FIG. [Figure 7] 1. FIG. 4 is a schematic diagram for explaining the timing and location of a flushing operation that is performed when one-way printing is performed only on the forward path in the inkjet printer shown in FIG. 1 with the logical seek function turned on. [Figure 8] 1. FIG. 4 is a schematic diagram for explaining the timing and location of a flushing operation that is performed when one-way printing is performed only on the forward path in the inkjet printer shown in FIG. 1 with the logical seek function turned on. [Figure 9] 1. FIG. 4 is a schematic diagram for explaining the timing and location of a flushing operation that is performed when one-way printing is performed only on the forward path in the inkjet printer shown in FIG. 1 with the logical seek function turned on. [Figure 10] 1. FIG. 4 is a schematic diagram for explaining the timing and location of a flushing operation that is performed when one-way printing is performed only on the forward path in the inkjet printer shown in FIG. 1 with the logical seek function turned on. [Figure 11] 10 is a flowchart for explaining a printing operation when a logical seek function is turned on in the inkjet printer shown in FIG. [Figure 12]12 is a flowchart for explaining the determination steps shown in FIG. 11. [Figure 13] 12 is a flowchart for explaining a second determination step shown in FIG. [Figure 14] 10 is a flowchart illustrating a determination step according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0025] (Inkjet printer configuration) Fig. 1 is a schematic diagram illustrating the configuration of an inkjet printer 1 according to an embodiment of the present invention, and Fig. 2 is a block diagram illustrating the configuration of the inkjet printer 1 shown in Fig. 1.

[0026] 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, fabric, or resin film. The medium 2 is, for example, formed in a long, rectangular shape. 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 in a main scanning direction (Y direction in FIG. 1, etc.) perpendicular to the up-down direction (vertical direction), a guide rail 6 for guiding the carriage 4 in the main scanning direction, and a platen 7 on which the medium 2 is placed. The printer 1 of this embodiment is a large printer that is wide in the main scanning direction. The printer 1 is capable of printing on a medium 2 that is, for example, approximately 3200 mm wide in the main scanning direction.

[0027] The printer 1 also includes a control unit 9 for controlling the printer 1. The printer 1 also includes a medium transport mechanism for transporting the medium 2 in a sub-scanning direction (X direction in FIG. 1, etc.) perpendicular to the up-down direction and the main scanning direction. The medium transport mechanism includes, for example, a transport roller for transporting the medium 2, a roller drive mechanism for driving the transport roller, and a plurality of pinch rollers arranged opposite the transport roller and biased toward the transport roller. The roller drive mechanism includes a motor as a drive source. The medium 2 is transported while sandwiched between the transport roller and the pinch roller.

[0028] In the following description, the main scanning direction (Y direction) is referred to as the "left-right direction," and the sub-scanning direction (X direction) is referred to as the "front-rear direction." Furthermore, the Y1 direction side in FIG. 1, etc., which is one side of the left-right direction, is referred to as the "left side," and the Y2 direction side in FIG. 1, etc., which is the opposite side of the left side, is 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). Furthermore, the left-right direction (Y direction) in this embodiment is the width direction of the medium 2. Furthermore, the up-down direction is the thickness direction of the medium 2 placed on the platen 7 during printing, and the front-rear direction (X direction) is the transport direction of the medium 2 moving over the platen 7.

[0029] The head 3 ejects ink downward. The head 3 of this embodiment ejects, for example, water-based ink. An ink ejection surface is formed on the underside of the head 3, on which a large number of nozzles that eject ink are arranged. The ink ejection surface has 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 a control unit 9. A platen 7 is arranged below the head 3. The medium 2 to be printed is placed on the platen 7.

[0030] The carriage drive mechanism 5 includes a motor 11 as a drive source and a power transmission mechanism that transmits the power of the motor 11 to the carriage 4. The power transmission mechanism includes, for example, two pulleys and a belt that is stretched over the two pulleys and has a portion fixed to the carriage 4. The head 3 mounted on the carriage 4 moves left and right together with the carriage 4 (main scanning direction).

[0031] The printer 1 is equipped with an encoder 12 for detecting the position of the carriage 4 in the left-right direction (i.e., for detecting the position of the head 3 in the main scanning direction). The encoder 12 is, for example, a rotary encoder having a rotary scale and a sensor, or a linear encoder having a linear scale and a sensor. The encoder 12 is electrically connected to the control unit 9. Specifically, the sensor of the encoder 12 is electrically connected to the control unit 9. In this embodiment, the current position of the head 3 is detected based on the detection result of the encoder 12.

[0032] The printer 1 is capable of two types of printing: bidirectional printing, in which ink is ejected from the head 3 on the outbound path where the carriage 4 moves to the left and on the inbound path where the carriage 4 moves to the right, to print on the medium 2; and unidirectional printing, in which ink is ejected from the head 3 only on the outbound path where the carriage 4 moves to the left, or only on the inbound path where the carriage 4 moves to the right, to print on the medium 2. The printer 1 also performs printing on the medium 2 by alternately repeating one pass (one operation) of the carriage 4 to the left or right and the operation of transporting the medium 2 by the medium transport mechanism.

[0033] In printer 1, a flushing operation is performed to forcibly eject ink from the nozzles of head 3 to prevent clogging of the many nozzles in head 3. Printer 1 is equipped with flushing boxes 15 and 16 that receive ink ejected from head 3 during the flushing operation. Printer 1 is also equipped with a capping mechanism 17 that suppresses an increase in the viscosity of ink in the nozzles of head 3 when head 3 is at rest, i.e., when the head 3 is not ejecting ink. Flushing boxes 15 and 16 are formed, for example, in the shape of a rectangular box with an open top. Capping mechanism 17 is equipped with a cap member or the like that covers the ink ejection surface of head 3 from below.

[0034] If the area in the main scanning direction where printing is performed on the medium 2 by the head 3 is defined as the printing area PA, the flushing boxes 15, 16 and the capping mechanism 17 are installed in positions outside the printing area PA in the main scanning direction. Specifically, the flushing box 15 is located to the left of the platen 7, and the flushing box 16 is located to the right of the platen 7. The capping mechanism 17 is located to the right of the flushing box 16.

[0035] The left-right distance from the left end of the platen 7 to the flushing box 15 is equal to the left-right distance from the right end of the platen 7 to the flushing box 16. The flushing boxes 15, 16 and the capping mechanism 17 are disposed below the head 3. Furthermore, the flushing boxes 15, 16 and the capping mechanism 17 are disposed at the same position as the head 3 in the front-rear direction.

[0036] In this embodiment, the head 3 that ejects ink toward the flushing box 15 or the flushing box 16 during the flushing operation moves left and right together with the carriage 4. That is, in this embodiment, the flushing operation is performed when the moving head 3 (i.e., the head 3 performing the main scanning operation) that is moving left and right passes over the flushing boxes 15 and 16, so-called running flushing is performed. In this embodiment, the flushing box 15 is the first flushing box, and the flushing box 16 is the second flushing box.

[0037] In the following description, when distinguishing between the flushing operation (running flushing) performed on flushing box 15 and the flushing operation (running flushing) performed on flushing box 16, the flushing operation performed on flushing box 15 will be referred to as the "first flushing operation" and the flushing operation performed on flushing box 16 will be referred to as the "second flushing operation."

[0038] The printer 1 has a logical seek function, and when the logical seek function is on, the head 3 moves left and right in accordance with the width of the image to be printed on the medium 2. In other words, if an image printed by the head 3 in one pass of the carriage 4 moving left and right is considered a one-pass print image, when the logical seek function is on, the control unit 9 moves the head 3 by logical seek, which moves the head 3 left and right together with the carriage 4 in accordance with the print start position and print end position of the one-pass print image, so as to minimize the amount of movement of the head 3 when repeatedly printing the one-pass print image. On the other hand, when the logical seek function is off, the printer 1 prints on the medium 2, for example, by moving the head 3 left and right across the entire width of the medium 2.

[0039] Below, we will explain the timing and location of the flushing operation (specifically, running flushing) performed by printer 1 when the logical seek function is turned on (i.e., when printing on medium 2 is performed in logical seek mode).

[0040] (Example of an image printed on a medium and head operation) Figures 3 to 6 are schematic diagrams illustrating the timing and location of the flushing operation that is performed when bidirectional printing is performed with the logical seek function turned on in the printer 1 shown in Figure 1. Figures 7 to 10 are schematic diagrams illustrating the timing and location of the flushing operation that is performed when unidirectional printing on the forward path only is performed with the logical seek function turned on in the printer 1 shown in Figure 1.

[0041] Before describing the timing and location of the flushing operation performed by the printer 1 when the logical seek function is turned on, an example of an image printed on the medium 2 and the operation of the head 3 will be described. As described above, if the image printed by the head 3 in one pass of the carriage 4 moving left and right is considered a one-pass print image, then the one-pass print image shown in Figures 3 to 10 is printed on the medium 2, for example. Figures 3 to 10 illustrate the state in which three one-pass print images have been printed on the medium 2.

[0042] 3 to 10, after the printer 1 starts printing the medium 2, the head 3 in a state before the start of printing the first one-pass print image is designated "3A," the head 3 in a state after the printing operation of this one-pass print image is completed is designated "3B," the head 3 in a state before the start of printing the next one-pass print image is designated "3C," the head 3 in a state after the printing operation of this one-pass print image is completed is designated "3D," the head 3 in a state before the start of printing the next one-pass print image is designated "3E," and the head 3 in a state after the printing operation of this one-pass print image is completed is designated "3F." The head 3 (head 3A) before the start of printing the first one-pass print image is disposed above the capping mechanism 17, for example.

[0043] In the following explanation, in Figure 3, after printer 1 starts printing on medium 2, the first one-pass printed image to be printed is referred to as image P11, the one-pass printed image to be printed after image P11 is referred to as image P12, and the one-pass printed image to be printed after image P12 is referred to as image P13. Similarly, in each of Figures 4 to 10, after printer 1 starts printing on medium 2, the first one-pass printed images are images P21, P31, P41, P51, P61, P71, and P81, the one-pass printed images printed after images P21, P31, P41, P51, P61, P71, and P81 are images P22, P32, P42, P52, P62, P72, and P82, and the one-pass printed images printed after images P22, P32, P42, P52, P62, P72, and P82 are images P23, P33, P43, P53, P63, P73, and P83 (see Figures 4 to 10).

[0044] 3 to 6 are printed using bidirectional printing, so when images P11, P13, P21, P23, P31, P33, P41, and P43 are printed, head 3 moves to the left together with carriage 4, and when images P12, P22, P32, and P42 are printed, head 3 moves to the right together with carriage 4. Images P51 to P53, P61 to P63, P71 to P73, and P81 to P83 shown in FIGS. 7 to 10 are printed using unidirectional printing on the forward path only, so when images P51 to P53, P61 to P63, P71 to P73, and P81 to P83 are printed, head 3 moves to the left together with carriage 4.

[0045] In this embodiment, images P11, P13, P21, P23, P31, P33, P41, P43, P51-P53, P61-P63, P71-P73, and P81-P83 are first print images, which are one-pass print images printed by the head 3 moving to the left. Images P12, P22, P32, and P42 are second print images, which are one-pass print images printed by the head 3 moving to the right.

[0046] (Flushing timing and location) Fig. 11 is a flowchart for explaining the printing operation when the logical seek function is turned on in the printer 1 shown in Fig. 1. Fig. 12 is a flowchart for explaining the determination step S2 shown in Fig. 11. Fig. 13 is a flowchart for explaining the second determination step S6 shown in Fig. 11.

[0047] Before the printer 1 starts printing on the medium 2, print data for printing on the medium 2 is input to the control unit 9. The print data includes, for example, the print range of the one-pass print image in the left-right direction, and the control unit 9 determines the print start position and print end position of the one-pass print image based on the print data. Alternatively, the control unit 9 determines the print range of the one-pass print image in the left-right direction based on the input print data, and also determines the print start position and print end position of the one-pass print image.

[0048] When printing on the medium 2, the control unit 9 first checks the print end position of the first one-pass print image before printing the first one-pass print image (step S1). That is, in step S1, the control unit 9 checks the print end positions of images P11, P21, P31, P41, P51, P61, P71, and P81. Thereafter, the control unit 9 determines whether or not to perform a flushing operation after printing images P11, P21, P31, P41, P51, P61, P71, and P81 (determination step, step S2). That is, in step S2, the control unit 9 determines whether or not to perform a flushing operation on the flushing box 15 after printing images P11, P21, P31, P41, P51, P61, P71, and P81.

[0049] In step S2, the control unit 9 first determines whether the print end positions of images P11, P21, P31, P41, P51, P61, P71, and P81 exceed a predetermined reference position (step S21). In this embodiment, in step S21, the control unit 9 determines whether the print end positions of images P11, P21, P31, P41, P51, P61, P71, and P81 exceed the center CL of the platen 7 in the left-right direction in the movement direction of the head 3 during printing (i.e., whether the print end positions of images P11, P21, P31, P41, P51, P61, P71, and P81 are to the left of the center CL of the platen 7).

[0050] In cases where the print end position is to the left of the center CL of the platen 7 and exceeds the center CL of the platen 7, as in the cases of images P11, P31, P51, and P71, the control unit 9 determines to perform a flushing operation (specifically, to perform a first flushing operation) after printing of images P11, P31, P51, and P71 (step S22). On the other hand, in cases where the print end position is to the right of the center CL of the platen 7 and does not exceed the center CL of the platen 7, as in the cases of images P21, P41, P61, and P81, the control unit 9 determines not to perform a flushing operation (specifically, not to perform a first flushing operation) after printing of images P21, P41, P61, and P81 (step S23).

[0051] When step S22 or step S23 is completed, step S2 is completed. When step S2 is completed, the control unit 9 prints the one-pass print image (step S3). That is, in step S3, the control unit 9 controls the piezoelectric element 10 and the motor 11 based on the detection result of the encoder 12 to print images P11, P21, P31, P41, P51, P61, P71, and P81.

[0052] If it is determined in step S2 that a flushing operation is to be performed, the control unit 9 performs a first flushing operation in step S3 by moving the head 3 to the left after printing the one-pass print image (i.e., by moving the carriage 4 to the left) (see FIGS. 3, 5, 7, and 9). When the first flushing operation is to be performed, the head 3, which has completed printing the one-pass print image, stops on the left side of the flushing box 15.

[0053] On the other hand, if it is determined in step S2 that the flushing operation will not be performed, the control unit 9 stops the head 3 (i.e., stops the carriage 4) after printing the one-pass print image in step S3, and does not perform the first flushing operation (see FIGS. 4, 6, 8, and 10). If the first flushing operation is not performed, the head 3, which has finished printing the one-pass print image, stops to the left of the printing end position of the one-pass print image.

[0054] If the number of one-pass operations of the carriage 4 without a flushing operation since printing on the medium 2 started or since the previous flushing operation was performed is defined as the number of non-flushing operations, the number of non-flushing operations is stored in the control unit 9. In this embodiment, if a flushing operation is performed in step S3, the control unit 9 resets the number of non-flushing operations to "0" in step S3. On the other hand, if a flushing operation is not performed in step S3, the control unit 9 increments the number of non-flushing operations in step S3. If images P21, P41, P61, and P81 are printed in step S3, the number of non-flushing operations is incremented to "1" in step S3.

[0055] The control unit 9 then determines whether printing on the medium 2 is complete (step S4). Even though printing of images P11, P21, P31, P41, P51, P61, P71, and P81 is complete, printing on the medium 2 is not complete, so the control unit 9 checks the print start position of the next one-pass print image (step S5). That is, in step S5, the control unit 9 checks the print start position of images P12, P22, P32, P42, P52, P62, P72, and P82. The control unit 9 then determines whether to perform a flushing operation on the flushing boxes 15 and 16 before printing the next one-pass print images, images P12, P22, P32, P42, P52, P62, P72, and P82 (second determination step, step S6).

[0056] In step S6, the control unit 9 first determines whether or not it is possible to skip the flushing operation (step S31). Specifically, in step S31, the control unit 9 determines whether or not the number of unperformed flushing operations stored in the control unit 9 exceeds a predetermined reference number, and determines that it is possible to skip the flushing operation if the number of unperformed flushing operations is equal to or less than the reference number, and determines that it is not possible to skip the flushing operation if the number of unperformed flushing operations exceeds the reference number.

[0057] In this embodiment, the reference number of times is two. Therefore, if the next one-pass print image is image P12, P22, P32, P42, P52, P62, P72, or P82, the number of times that flushing has not been performed will be less than the reference number, and the flushing operation can be skipped in step S31. The reference number of times may be one, or three or more. The reference number of times is set, for example, depending on the type of ink ejected by the head 3.

[0058] If it is possible to skip the flushing operation in step S31, the control unit 9 determines whether the pre-printing movement distance, which is the horizontal distance between the print start position of the next one-pass print image and the current position of the head 3, exceeds a predetermined reference distance LB (see FIG. 3) (step S32). In this embodiment, the reference distance LB is the same distance as half the horizontal width of the platen 7. Furthermore, if the next one-pass print image is images P12, P22, P32, P42, P52, P62, P72, or P82, the current position of the head 3 in step S32 is the position of the head 3B in FIGS. 3 to 10.

[0059] 3, if the pre-printing movement distance L1, which is the left-right distance between the print start position of image P12 and the current position of head 3, is less than or equal to reference distance LB and does not exceed reference distance LB, control unit 9 determines not to perform the flushing operation before printing image P12, which is the next one-pass print image (step S33). Similarly, if the pre-printing movement distance is less than reference distance LB, as shown in FIGS. 4, 5, and 8 to 10, the process proceeds to step S33.

[0060] 6 and 7, if the pre-printing movement distance exceeds the reference distance LB, the control unit 9 selects either the flushing box 15 or the flushing box 16 (step S34). Specifically, in step S34, the control unit 9 selects the flushing box 16 if the next one-pass print image is the first print image (i.e., if it is a one-pass print image printed by the head 3 moving to the left, for example, image P52), and selects the flushing box 15 if the next one-pass print image is the second print image (i.e., if it is a one-pass print image printed by the head 3 moving to the right, for example, image P42).

[0061] Thereafter, the control unit 9 determines whether the current position of the head 3 is outside the flushing boxes 15, 16 selected in step S34 in the left-right direction (step S35). As shown in Fig. 6, if the current position of the head 3 is to the right of the flushing box 15 selected in step S34, the control unit 9 determines to perform a flushing operation on the selected flushing box 15 before printing the next one-pass print image, image P42 (step S36). Also, as shown in Fig. 7, if the current position of the head 3 is to the left of the flushing box 16 selected in step S34, the control unit 9 proceeds to step S36 and determines to perform a flushing operation on the selected flushing box 16 before printing the next one-pass print image, image P52.

[0062] On the other hand, in step S35, if the current position of the head 3 is outside the flushing boxes 15, 16 selected in step S34 in the left-right direction, the process proceeds to step S33. Also, if it is not possible to skip the flushing operation in step S31, the process proceeds to step S34.

[0063] When step S33 or step S36 is completed, step S6 is completed. When step S6 is completed, the control unit 9 determines, based on the result of step S6, whether or not to perform a flushing operation before printing the next one-pass print images P12, P22, P32, P42, P52, P62, P72, and P82 (step S7).

[0064] When the carriage 4 performs a preliminary operation when the head 3 moves from its current position to the print start position of the next one-pass print image (for example, the carriage 4 performs an operation when the head 3 moves from the position of head 3B to the position of head 3C), if a flushing operation is to be performed before printing images P42 and P52, as shown in Figures 6 and 7, the control unit 9 causes the carriage 4 to perform a preliminary operation involving a flushing operation (step S8) and returns to step S1. In step S8, the control unit 9 resets the number of unperformed flushing operations to "0".

[0065] On the other hand, as shown in FIGS. 3 to 5 and 8 to 10, if a flushing operation is not performed before printing images P12, P22, P32, P62, P72, and P82, the control unit 9 determines whether the current position of the head 3 coincides with the print start position of the next one-pass print image (step S9). As shown in FIG. 4, if the current position of the head 3 coincides with the print start position of image P22, which is the next one-pass print image, and preparatory operation is not required, the process returns to step S1. On the other hand, as shown in FIGS. 3, 5, and 8 to 10, if the current position of the head 3 does not coincide with the print start position of the next one-pass print image and preparatory operation is required, the control unit 9 causes the carriage 4 to perform a preparatory operation that does not involve a flushing operation (step S10), and then returns to step S1. In step S10, the control unit 9 increments the number of flushing operations not yet performed.

[0066] When returning to step S1 from step S8, step S9, or step S10, the control unit 9 checks the print end positions of images P12, P22, P32, P42, P52, P62, P72, and P82, which are the one-pass print images to be printed, before printing them in step S1. In addition, the control unit 9 determines in step S2 whether to perform a flushing operation on flushing box 15 or flushing box 16.

[0067] In step S2, the control unit 9 determines to perform the second flushing operation after printing images P12 and P22 if the printing end position is to the right of the center CL of the platen 7, as in images P12 and P22, and determines to perform the first flushing operation after printing images P52, P72, and P82 if the printing end position is to the left of the center CL of the platen 7, as in images P52, P72, and P82. Also in step S2, the control unit 9 determines not to perform the flushing operation after printing images P32, P42, and P62 if the printing end position is to the left of the center CL of the platen 7, as in images P32 and P42, and if the printing end position is to the right of the center CL of the platen 7, as in image P62.

[0068] If it is determined in step S2 that a flushing operation is to be performed, the control unit 9 performs the flushing operation in step S3 by printing the one-pass print image and then moving the head 3 (i.e., moving the carriage 4) (see FIGS. 3, 4, 7, 9, and 10). On the other hand, if it is determined in step S2 that a flushing operation is not to be performed, the control unit 9 performs the flushing operation in step S3 by printing the one-pass print image and then stopping the head 3 (i.e., stopping the carriage 4) (see FIGS. 5, 6, and 8).

[0069] Then, in step S4, the control unit 9 determines whether printing on medium 2 is complete. However, even though printing of images P12, P22, P32, P42, P52, P62, P72, and P82 is complete, printing on medium 2 is not complete. Therefore, in step S5, the control unit 9 checks the print start positions of the next one-pass print images, images P13, P23, P33, P43, P53, P63, P73, and P83. Then, in step S6, the control unit 9 determines whether to perform a flushing operation on the flushing boxes 15 and 16 before printing images P13, P23, P33, P43, P53, P63, P73, and P83.

[0070] Step S6 is executed as described above. In the example shown in Fig. 3, the pre-printing movement distance L2, which is the left-right distance between the print start position of image P13 and the current position of head 3, exceeds the reference distance LB, so the process proceeds from step S32 to step S34. In step S34, the control unit 9 selects flushing box 16 because image P13 is the first print image. Also, in the example shown in Fig. 3, the current position of head 3 (the position of head 3D) is to the right of the flushing box 16 selected in step S34, so the process proceeds from step S35 to step S33.

[0071] 8, when the next one-pass print image to be printed is image P63, the number of times that flushing has not been performed is three, which exceeds the reference number of two. Therefore, in step S31, it is determined that skipping the flushing operation is not possible, and the process proceeds from step S31 to step S34. In step S34, the control unit 9 selects flushing box 16 because image P63, the next one-pass print image, is the first print image. Also, in the example shown in FIG. 8, the current position of head 3 (the position of head 3D) is to the left of the flushing box 16 selected in step S34, so the process proceeds to step S36.

[0072] When returning to step S1 from step S8, step S9, or step S10, steps S1 to S3 are executed in the same manner. When step S3 is executed and printing on medium 2 is completed (step S4 becomes "Yes"), the control unit 9 moves the head 3 above the capping mechanism 17 (step S11). When step S11 ends, the printing operation on medium 2 in the printer 1 is completed.

[0073] Thus, in this embodiment, when bidirectional printing is performed in the printer 1, the control unit 9 determines in step S2, before printing the first print images P11, P13, P21, P23, P31, P33, P41, and P43, whether or not to perform a first flushing operation after printing the first print images, based on the print end position of the first print images. Also, when bidirectional printing is performed in the printer 1, the control unit 9 determines in step S2, before printing the second print images P12, P22, P32, and P42, whether or not to perform a second flushing operation after printing the second print images, based on the print end position of the second print images.

[0074] Furthermore, when unidirectional printing is performed on the forward pass only in the printer 1, the control unit 9 determines in step S2, before printing the first print images P51-P53, P61-P63, P71-P73, and P81-P83, that is, images P51-P53, P61-P63, P71-P73, and P81-P83, whether or not to perform a first flushing operation after printing the first print images, based on the print end position of the first print images. Note that, when unidirectional printing is performed on the return pass only in the printer 1, the control unit 9 determines in step S2, before printing the second print image, whether or not to perform a second flushing operation after printing the second print image, based on the print end position of the second print image, just as when unidirectional printing is performed on the forward pass only in the printer 1.

[0075] In addition, in this embodiment, if the printing end position of the first print image is to the left of the center CL of the platen 7 in the left-right direction, the first flushing operation is performed unconditionally after printing the first print image, and if the printing end position of the second print image is to the right of the center CL of the platen 7, the second flushing operation is performed unconditionally after printing the second print image.

[0076] Furthermore, in this embodiment, in step S6, the control unit 9 determines whether to perform a flushing operation on the flushing box 15 or on the flushing box 16 before printing the next first-pass print image, depending on the pre-printing movement distance, which is the horizontal distance between the print start position of the next one-pass print image and the current position of the head 3. Furthermore, if the pre-printing movement distance is longer than the reference distance LB, which is the same distance as half the horizontal width of the platen 7, the control unit 9 performs a flushing operation on the flushing box 15 or on the flushing box 16 before printing the next first-pass print image, if certain conditions are met.

[0077] Specifically, in step S6, the control unit 9 determines whether to perform a flushing operation on the flushing box 15 or on the flushing box 16 before printing the next first-pass print image, depending on the pre-printing movement distance and the current position of the head 3. Furthermore, if the printing of the next one-pass print image is the printing of the first print image, and the current position of the head 3 is to the right of the flushing box 16, the control unit 9 does not perform the second flushing operation before printing the next first print image. Similarly, if the printing of the next one-pass print image is the printing of the second print image, and the current position of the head 3 is to the left of the flushing box 15, the control unit 9 does not perform the first flushing operation before printing the next second print image.

[0078] Furthermore, in this embodiment, in step S6, the control unit 9 determines whether to perform a flushing operation on the flushing box 15 or on the flushing box 16 before printing the next first-pass print image, depending on the pre-printing movement distance and the number of times flushing operations have not been performed, and if the number of times flushing operations have not been performed is equal to or less than a reference number and certain conditions are met, no flushing operation will be performed before printing the next first-pass print image.

[0079] (Main effect of this form) As described above, in this embodiment, before printing the first print image, the control unit 9 determines whether or not to perform a first flushing operation after printing the first print image, depending on the printing end position of the first print image, and before printing the second print image, determines whether or not to perform a second flushing operation after printing the second print image, depending on the printing end position of the second print image.

[0080] Therefore, in this embodiment, if the printing end position of the first print image is close to the flushing box 15, the first flushing operation is performed after the first print image is printed, and if the printing end position of the first print image is far from the flushing box 15, the first flushing operation is not performed after the first print image is printed. Also, if the printing end position of the second print image is close to the flushing box 16, the second flushing operation is performed after the second print image is printed, and if the printing end position of the second print image is far from the flushing box 16, the second flushing operation is not performed after the second print image is printed. Therefore, in this embodiment, it is possible to efficiently perform flushing operations when printing by moving the head 3 using logical seek.

[0081] In this embodiment, if the printing end position of the first print image is to the left of the center CL of the platen 7 in the left-right direction, the first flushing operation is unconditionally performed after the first print image is printed, and if the printing end position of the second print image is to the right of the center CL of the platen 7, the second flushing operation is unconditionally performed after the second print image is printed. That is, in this embodiment, the center CL of the platen 7 is used as a reference to determine whether or not to perform the flushing operation on the flushing boxes 15, 16. Therefore, in this embodiment, it is possible to appropriately determine whether or not to perform the flushing operation on the flushing boxes 15, 16.

[0082] In this embodiment, in step S6, the control unit 9 determines whether to perform a flushing operation on the flushing box 15 or on the flushing box 16 before printing the next first-pass print image, depending on the pre-printing movement distance, which is the horizontal distance between the print start position of the next one-pass print image and the current position of the head 3. Therefore, in this embodiment, if the pre-printing movement distance is long and ink viscosity is likely to increase, it is possible to perform a flushing operation before printing the next one-pass print image, and if the pre-printing movement distance is short and ink viscosity is unlikely to increase, it is possible to not perform a flushing operation before printing the next one-pass print image. Therefore, in this embodiment, it is possible to perform a flushing operation more efficiently.

[0083] In this embodiment, if the printing of the next one-pass print image is the printing of the first print image, and the current position of the head 3 is to the right of the flushing box 16, the second flushing operation is not performed before the printing of the next first print image. Also, in this embodiment, if the printing of the next one-pass print image is the printing of the second print image, and the current position of the head 3 is to the left of the flushing box 15, the first flushing operation is not performed before the printing of the next second print image. If the printing of the next one-pass print image is the printing of the first print image and the current position of the head 3 is to the right of the flushing box 16, or if the printing of the next one-pass print image is the printing of the second print image and the current position of the head 3 is to the left of the flushing box 15, it is assumed that the flushing operation is performed immediately before the head 3 moves to its current position. Therefore, in this embodiment, it is possible to prevent excessive flushing operations from being performed.

[0084] In this embodiment, in step S6, the control unit 9 determines whether to perform a flushing operation on the flushing box 15 or on the flushing box 16 before printing the next first-pass print image, depending on the pre-printing movement distance and the number of times that flushing operations have not been performed, and if the number of times that flushing operations have not been performed is equal to or less than a reference number and certain conditions are met, the flushing operation will not be performed before printing the next first-pass print image. Therefore, in this embodiment, when print quality can be ensured even if the frequency of flushing operations is reduced, it is possible to perform flushing operations efficiently.

[0085] (Example of change to the second decision step) In the above-described embodiment, if the operation distance (movement distance) of the carriage 4 without a flushing operation after the start of printing or after the previous flushing operation is defined as the non-flushing operation distance, the non-flushing operation distance may be stored in the control unit 9 instead of the number of non-flushing operations. In this case, in step S31, the control unit 9 determines whether the non-flushing operation distance exceeds a predetermined reference distance, and if the non-flushing operation distance is equal to or less than the reference distance, determines that the flushing operation can be skipped, and if the non-flushing operation distance exceeds the reference distance, determines that the flushing operation cannot be skipped.

[0086] That is, in this modified example, in step S6, the control unit 9 determines whether to perform a flushing operation on the flushing box 15 or on the flushing box 16 before printing the next first pass print image, depending on the pre-printing movement distance and the non-flushing operation distance, and if the non-flushing operation distance is less than the reference distance and certain conditions are met, the control unit 9 does not perform a flushing operation before printing the next first pass print image.

[0087] In this modified example, if a flushing operation is performed in step S3, the control unit 9 resets the non-flushing operation distance to "0" in step S3, and if a flushing operation is not performed in step S3, the control unit 9 updates the non-flushing operation distance in step S3. In this modified example, the control unit 9 resets the non-flushing operation distance to "0" in step S8, and updates the non-flushing operation distance in step S10.

[0088] (Example of changing decision steps) FIG. 14 is a flowchart for explaining the determination step S2 according to another embodiment of the present invention.

[0089] In the embodiment described above, the control unit 9 may determine whether or not the flushing operation can be skipped if the print end position of the one-pass print image exceeds the reference position in step S21 (step S24). In this modification, the control unit 9 determines whether or not the number of unperformed flushing operations stored in the control unit 9 exceeds a predetermined reference number in step S24, and determines that the flushing operation can be skipped if the number of unperformed flushing operations is equal to or less than the reference number, and determines that the flushing operation cannot be skipped if the number of unperformed flushing operations exceeds the reference number. In this case, the reference number is, for example, two times. However, the reference number may also be one time, or three or more times. The reference number is set, for example, depending on the type of ink ejected by the head 3.

[0090] In this modified example, if skipping the flushing operation is not possible in step S24, the process proceeds to step S22, and if skipping the flushing operation is possible in step S24, the process proceeds to step S22. That is, in this modified example, if the printing end position of the first print image is to the left of the center CL in the left-right direction of the platen 7 and certain conditions are met, the first flushing operation is performed after printing the first print image, and if the printing end position of the second print image is to the right of the center CL of the platen 7 and certain conditions are met, the second flushing operation is performed after printing the second print image.

[0091] In this way, in step S2, it is possible to determine whether to perform the first flushing operation after printing the first print image based on the printing end position of the first print image and the number of non-flushing operations, and to determine whether to perform the second flushing operation after printing the second print image based on the printing end position of the second print image and the number of non-flushing operations. Furthermore, if the number of non-flushing operations is equal to or less than the reference number and a flushing operation can be skipped, it is possible not to perform the first flushing operation after printing the first print image, and not to perform the second flushing operation after printing the second print image. In this modified example, it is possible to efficiently perform flushing operations, for example, even when using ink that can ensure print quality even when the frequency of flushing operations is reduced.

[0092] In step S24, the control unit 9 determines whether the non-flushing operation distance exceeds a predetermined reference distance, and may determine that the flushing operation can be skipped if the non-flushing operation distance is less than the reference distance, or that the flushing operation cannot be skipped if the non-flushing operation distance exceeds the reference distance.

[0093] That is, in step S2, the control unit 9 may determine whether to perform the first flushing operation after printing the first print image based on the printing end position of the first print image and the non-flushing operation distance, and may determine whether to perform the second flushing operation after printing the second print image based on the printing end position of the second print image and the non-flushing operation distance. In this case, if the non-flushing operation distance is equal to or shorter than the reference distance, the first flushing operation is not performed after printing the first print image, and the second flushing operation is not performed after printing the second print image.

[0094] (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 within the scope of the present invention.

[0095] In the above-described embodiment, the reference position that is compared with the printing end position of the one-pass print image in step S21 may be a position that is shifted from the center CL in the left-right direction of the platen 7. Also, in the above-described embodiment, the reference distance LB that is compared with the pre-printing movement distance in step S32 may be a distance that is longer than half the left-right width of the platen 7, or may be a distance that is shorter than half the left-right width of the platen 7.

[0096] In the above-described embodiment, steps S31 and S32 may be interchanged. In this case, if in step S32 the pre-printing movement distance, which is the left-right distance between the print start position of the next one-pass print image and the current position of the head 3, is less than or equal to the reference distance LB, the process proceeds to step S31. If the pre-printing movement distance, which is the left-right distance between the print start position of the next one-pass print image and the current position of the head 3, exceeds the reference distance LB, the process proceeds to step S34. Also, if in step S31 it is possible to skip the flushing operation, the process proceeds to step S33. If it is not possible to skip the flushing operation, the process proceeds to step S34. Also, in the above-described embodiment, step S31 may be omitted.

[0097] In the above-described embodiment, the printer 1 may include, instead of the platen 7, a table on which the medium 2 is placed and a table drive mechanism that moves the table back and forth. In this case, the flushing box 15 is disposed on the left side of the table, and the flushing box 16 is disposed on the right side of the table. Also, in the above-described embodiment, the printer 1 may be a 3D printer that forms a three-dimensional object. In this case, the printer 1 includes a table on which the three-dimensional object is placed. [Explanation of symbols]

[0098] 1. Printer (inkjet printer) 3 heads (inkjet heads) 4 carriages 5 Carriage drive mechanism 7 Platen 9 Control Unit 15 Flushing box (first flushing box) 16 Flushing box (second flushing box) CL Center of the platen in the main scanning direction L1, L2 Travel distance before printing P11, P13, P21, P23, P31, P33, P41, P43, P51 to P53, P61 to P63, P71 to P73, P81 to P83 1st pass print image, 1st print image P12, P22, P32, P42 1st pass print image, 2nd print image S2 Decision Step S6 Second decision step Y main scanning direction Y1 1st direction side Y2 Second direction side

Claims

1. In an inkjet printer equipped with an inkjet head that ejects ink, the inkjet printer comprises 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, a platen or table disposed below the inkjet head, a first flushing box and a second flushing box disposed below the inkjet head and for receiving ink ejected from the inkjet head during a flushing operation, and a control unit for controlling the inkjet printer, 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: the first flushing box is disposed on the first direction side of the platen or the table, the second flushing box is disposed on the second direction side of the platen or the table, the inkjet head that ejects ink toward the first flushing box or the second flushing box by the flushing operation moves in a main scanning direction together with the carriage, An image printed by the inkjet head during one pass of the carriage in the main scanning direction is defined as a one-pass printed image, the one-pass printed image printed by the inkjet head moving together with the carriage toward the first direction is defined as a first printed image, the one-pass printed image printed by the inkjet head moving together with the carriage toward the second direction is defined as a second printed image, the flushing operation performed on the first flushing box is defined as a first flushing operation, and the flushing operation performed on the second flushing box is defined as a second flushing operation. The control unit receives print data before printing begins, The control unit moving the inkjet head in the main scanning direction by logical seek, which moves the inkjet head together with the carriage in the main scanning direction according to a print start position and a print end position of the one-pass print image; Before printing the first print image, it is determined whether or not the first flushing operation is to be performed after printing the first print image according to a print end position of the first print image; and An inkjet printer characterized in that, before printing the second print image, it is determined whether or not to perform the second flushing operation after printing the second print image according to a printing end position of the second print image.

2. an inkjet head that ejects ink; a carriage on which the inkjet head is mounted; a carriage drive mechanism that reciprocates the carriage in a main scanning direction that is perpendicular to the up-down direction; a platen or table that is disposed below the inkjet head; and a first flushing box and a second flushing box that are disposed below the inkjet head and that receive ink ejected from the inkjet head during a flushing operation; 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: the first flushing box is disposed on the first direction side of the platen or the table, the second flushing box is disposed on the second direction side of the platen or the table, the inkjet head that ejects ink toward the first flushing box or the second flushing box by the flushing operation moves in a main scanning direction together with the carriage, If an image printed by the inkjet head in one pass of the carriage in the main scanning direction is defined as a one-pass printed image, moving the inkjet head in the main scanning direction by logical seek, which moves the inkjet head together with the carriage in the main scanning direction according to a print start position and a print end position of the one-pass print image; A method for controlling an inkjet printer in which print data is input before printing begins, comprising: a determining step of determining whether the flushing operation is to be performed on the first flushing box or the second flushing box, The one-pass printed image printed by the inkjet head moving together with the carriage in the first direction is defined as a first printed image, the one-pass printed image printed by the inkjet head moving together with the carriage in the second direction is defined as a second printed image, the flushing operation performed on the first flushing box is defined as a first flushing operation, and the flushing operation performed on the second flushing box is defined as a second flushing operation. In the judgment step, before printing the first print image, it is judged whether or not the first flushing operation will be performed after printing the first print image in accordance with the printing end position of the first print image, and before printing the second print image, it is judged whether or not the second flushing operation will be performed after printing the second print image in accordance with the printing end position of the second print image.

3. When a printing end position of the first print image is on the first direction side of the center of the platen or the table in the main scanning direction, the first flushing operation is performed after printing of the first print image unconditionally or when a certain condition is satisfied; A control method for an inkjet printer according to claim 2, characterized in that, when the printing end position of the second print image is on the second direction side of the center of the platen or the table in the main scanning direction, the second flushing operation is performed after printing the second print image unconditionally or when certain conditions are met.

4. The number of one-pass operations of the carriage without the flushing operation after the start of printing or after the previous flushing operation is defined as the number of non-flushing operations, and the operation distance of the carriage without the flushing operation after the start of printing or after the previous flushing operation is defined as the non-flushing operation distance, In the determination step, it is determined whether or not the first flushing operation should be performed after printing of the first print image, depending on the print end position of the first print image and the number of non-flushing operations or the non-flushing operation distance, and it is determined whether or not the second flushing operation should be performed after printing of the second print image, depending on the print end position of the second print image and the number of non-flushing operations or the non-flushing operation distance, 4. A control method for an inkjet printer according to claim 2 or 3, characterized in that if the number of times that the flushing operation has not been performed is equal to or less than a predetermined reference number, or if the distance that the flushing operation has not been performed is equal to or less than a predetermined reference distance, the first flushing operation is not performed after printing the first print image, and the second flushing operation is not performed after printing the second print image.

5. 4. The inkjet printer control method according to claim 2, further comprising a second determination step of determining whether to perform the flushing operation on the first flushing box or the second flushing box before printing the next first-pass print image, in the case where the next one-pass print image is printed after the first-pass print image has been printed, based on a pre-printing movement distance, which is the distance in the main scanning direction between the print start position of the next one-pass print image and the current position of the inkjet head.

6. 6. A control method for an inkjet printer according to claim 5, wherein, when the pre-printing movement distance is longer than half the width of the platen or the table in the main scanning direction, if a certain condition is met, the flushing operation is performed on the first flushing box or the second flushing box before printing the next first pass print image.

7. in the second determination step, it is determined whether the flushing operation is to be performed on the first flushing box or the second flushing box before printing the next first-pass print image, depending on the pre-printing movement distance and a current position of the inkjet head; When the printing of the next one-pass print image is the printing of the first print image, if the current position of the inkjet head is on the second direction side of the second flushing box, the second flushing operation is not performed before the printing of the next first print image, 6. A control method for an inkjet printer according to claim 5, wherein when the printing of the next one-pass print image is the printing of the second print image, if the current position of the inkjet head is on the first direction side of the first flushing box, the first flushing operation is not performed before the printing of the next second print image.

8. The number of one-pass operations of the carriage without the flushing operation after the start of printing or after the previous flushing operation is defined as the number of non-flushing operations, and the operation distance of the carriage without the flushing operation after the start of printing or after the previous flushing operation is defined as the non-flushing operation distance, in the second determination step, it is determined whether the flushing operation is to be performed on the first flushing box or the second flushing box before printing the next first pass print image, depending on the pre-printing movement distance and the number of times the flushing operation has not been performed or the distance the flushing operation has not been performed, 6. A control method for an inkjet printer according to claim 5, wherein if the number of times the flushing operation has not been performed is equal to or less than a predetermined reference number, or if the distance the flushing operation has not been performed is equal to or less than a predetermined reference distance, and if certain conditions are met, the flushing operation is not performed before printing the next first pass print image.

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