Liquid discharge device and control method for liquid discharge device

Abstract

To provide a liquid discharge device and a control method for the liquid discharge device that can reduce the amount of liquid consumed during flushing.SOLUTION: A liquid discharge device includes: a printing unit 18 that performs printing on a medium 21 by discharging liquid from a plurality of nozzles; an irradiation unit 17 that cures the discharged liquid by irradiating light; and a control unit 13. The control unit 13 is capable of executing flushing in which liquid is discharged from the plurality of nozzles independently of printing, and changes the idle discharge amount of each nozzle during flushing on the basis of the degree of influence of light irradiated from the irradiation unit 17 on each nozzle and the printing discharge amount of each nozzle during printing.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection device such as a printer, and a method for controlling a liquid ejection device. [Background technology]

[0002] For example, there is an image forming apparatus, which is an example of a liquid ejection apparatus, as described in Patent Document 1. The image forming apparatus includes a plurality of head units, which are an example of a printing section, and an irradiation section. The head unit ejects ink, an example of a liquid, from nozzles to record on a recording medium, an example of a medium. The ink is cured by the action of energy rays, an example of light. The irradiation unit irradiates the recording medium onto which the ink has been ejected with energy rays, thereby curing the ink on the recording medium.

[0003] If the energy beam leaks near the nozzles, the ink before ejection may harden, causing nozzle clogging. Therefore, image forming devices perform maintenance, an example of flushing, which ejects ink from the nozzles. The image reading device increases the ink ejection volume of the head unit closest to the irradiation unit compared to the ink ejection volumes of the other head units. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-4701 Summary of the Invention [Problem to be solved by the invention]

[0005] Nozzle clogging can easily occur in nozzles that are far from the irradiation unit. For example, the ease with which a liquid hardens when exposed to light can vary depending on the type of liquid. The light emitted by the irradiation unit can affect nozzles that are far from the irradiation unit by being diffused by a medium, for example.

[0006] When a nozzle that is prone to clogging is located at a position far from the irradiation unit, if flushing is performed by increasing the ejection amount of the nozzle that is close to the irradiation unit, liquid will be consumed unnecessarily. [Means for solving the problem]

[0007] A liquid ejection device that solves the above problem comprises a printing unit that prints on a medium by ejecting liquid from multiple nozzles, an irradiation unit that hardens the ejected liquid by irradiating it with light, and a control unit, wherein the control unit is capable of performing flushing, in which the liquid is ejected from the multiple nozzles regardless of the printing, and changes the amount of empty ejection from each nozzle during the flushing based on the degree of effect on each nozzle of the light irradiated from the irradiation unit and the print ejection amount from each nozzle during the printing.

[0008] A control method for a liquid ejection device that solves the above problem is a control method for a liquid ejection device that includes a printing unit that prints on a medium by ejecting liquid from multiple nozzles, and an irradiation unit that hardens the ejected liquid by irradiating it with light, and calculates the degree of influence on each nozzle by the light irradiated from the irradiation unit, calculates the print ejection volume of each nozzle during the printing, and changes the idle ejection volume of each nozzle during flushing, which ejects the liquid from the multiple nozzles regardless of the printing, based on the degree of influence and the print ejection volume. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic front view of an embodiment of a liquid ejection device. [Figure 2] FIG. 2 is a schematic plan view of the movement mechanism. [Figure 3] FIG. 3 is a schematic bottom view of the carriage. [Figure 4] FIG. 4 is a flowchart showing the idle discharge amount setting routine. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Embodiment] An embodiment of a liquid ejection device and a method for controlling the liquid ejection device will be described below with reference to the drawings. The liquid ejection device is an inkjet printer that ejects ink, which is an example of a liquid, onto a medium such as paper, fabric, vinyl, plastic parts, or metal parts to record.

[0011] In the drawings, the liquid discharge device 11 is placed on a horizontal plane, with the direction of gravity indicated by the Z axis, and directions along the horizontal plane indicated by the X and Y axes, which are perpendicular to one another.

[0012] <Liquid discharge device> 1, the liquid ejection device 11 may include a housing 12. The housing 12 accommodates various components of the liquid ejection device 11.

[0013] The liquid ejection device 11 includes a control unit 13. The control unit 13 comprehensively controls the driving of each mechanism in the liquid ejection device 11, and controls various operations executed by the liquid ejection device 11. The control unit 13 may be configured as a circuit including: α: one or more processors that execute various processes according to a computer program; β: one or more dedicated hardware circuits that execute at least some of the various processes; or γ: a combination thereof. The hardware circuit is, for example, an application-specific integrated circuit. The processor includes a CPU and memory such as RAM and ROM, and the memory stores program code or instructions configured to cause the CPU to execute processes. The memory, i.e., computer-readable medium, includes any readable medium that can be accessed by a general-purpose or dedicated computer.

[0014] The liquid ejection device 11 may include a support unit 15 , a carriage 16 , an irradiation unit 17 , a printing unit 18 , and a liquid receiving unit 19 . The support 15 is configured to support a medium 21 .

[0015] The carriage 16 may movably hold the irradiation unit 17 and the printing unit 18. The irradiation unit 17 and the printing unit 18 may be mounted on the carriage 16. The irradiation unit 17 cures the ejected liquid by irradiating it with light. For example, if the liquid is UV ink, the irradiation unit 17 irradiates it with ultraviolet light. The irradiation unit 17 cures the liquid ejected onto the medium 21, thereby fixing the liquid to the medium 21.

[0016] The liquid contains a component that hardens when exposed to light from the irradiation unit 17. For example, the liquid contains a photopolymerization initiator that initiates polymerization using ultraviolet energy. Examples of the photopolymerization initiator that can be used include a photoradical polymerization initiator and a photocationic polymerization initiator.

[0017] 2, the liquid discharger 11 may include a movement mechanism 23. The movement mechanism 23 may include a horizontal shaft 24 and a vertical shaft 25. The movement mechanism 23 of this embodiment includes a pair of vertical shafts 25.

[0018] The horizontal axis 24 may extend in the scanning direction Dx. The pair of vertical axes 25 may be arranged parallel to each other and extend in the sub-scanning direction Dy. In this embodiment, the scanning direction Dx is a direction parallel to the X-axis. In this embodiment, the sub-scanning direction Dy is a direction perpendicular to the X-axis and parallel to the Y-axis.

[0019] The movement mechanism 23 moves the carriage 16 back and forth along a horizontal axis 24. The carriage 16 is capable of moving the printing unit 18 in the scanning direction Dx. The movement mechanism 23 moves the horizontal axis 24, which supports the carriage 16, back and forth along a vertical axis 25. Therefore, the movement mechanism 23 is capable of moving the irradiation unit 17 and printing unit 18 mounted on the carriage 16 in the scanning direction Dx and the sub-scanning direction Dy.

[0020] The movement mechanism 23 may simultaneously move the printing unit 18 in the scanning direction Dx and the sub-scanning direction Dy. That is, the movement mechanism 23 may move the printing unit 18 obliquely with respect to the scanning direction Dx and the sub-scanning direction Dy so as to be along a horizontal plane.

[0021] In the liquid ejection device 11, a carriage 16 scans relative to a medium 21. A printing unit 18 prints an image on the medium 21 by ejecting liquid while scanning together with the carriage 16. The carriage 16 of this embodiment is configured to not only scan relative to the medium 21, but also move in a sub-scanning direction Dy that intersects with the scanning direction Dx. In other words, the liquid ejection device 11 of this embodiment is a so-called lateral printer.

[0022] <Print section> 3, the printing unit 18 performs printing on the medium 21 by ejecting liquid from a plurality of nozzles 27. The printing unit 18 may include a first ejection unit 29 and a second ejection unit 30.

[0023] The first discharge unit 29, the second discharge unit 30, and the irradiation unit 17 may be arranged side by side in the scanning direction Dx. The first discharge unit 29, the second discharge unit 30, and the irradiation unit 17 may be arranged at different positions in the scanning direction Dx and spaced apart from each other in the scanning direction Dx. The first discharge unit 29 and the second discharge unit 30 may be arranged at different positions in the sub-scanning direction Dy and partially overlap each other in the sub-scanning direction Dy. The second discharge unit 30 may be located downstream of the first discharge unit 29 in the scanning direction Dx and upstream of the sub-scanning direction Dy. The printing unit 18 may be smaller than the irradiation unit 17 in the sub-scanning direction Dy.

[0024] In this embodiment, the first discharge unit 29 and the second discharge unit 30 have the same configuration. Therefore, in the following description, the first discharge unit 29 will be described, and the common configuration will be denoted by the same reference numerals to avoid redundant description.

[0025] The first ejection unit 29 is configured to eject a liquid. The first ejection unit 29 has a plurality of nozzles 27. Each nozzle 27 is capable of ejecting a liquid. The first ejection unit 29 ejects the liquid onto the medium 21 supported by the support unit 15 while moving, thereby printing an image on the medium 21.

[0026] The first discharge unit 29 has a nozzle surface 32. A plurality of nozzle rows L are formed on the nozzle surface 32 by a plurality of nozzles 27. In this embodiment, a first nozzle row L1 to an eighth nozzle row L8 are formed on the nozzle surface 32. One nozzle row L is formed by a plurality of nozzles 27 aligned in the sub-scanning direction Dy. The sub-scanning direction Dy in which the plurality of nozzles 27 that form the nozzle row L are aligned may be parallel to the longitudinal direction of the irradiation unit 17.

[0027] The multiple nozzle rows L each extend in the sub-scanning direction Dy and are formed at predetermined intervals in the scanning direction Dx. The multiple nozzle rows L may be formed at equal intervals in the scanning direction Dx, or may be formed at different intervals. For example, among the first nozzle row L1 to the eighth nozzle row L8, some of the nozzle rows L may be arranged closely to each other in the scanning direction Dx. In this embodiment, two nozzle rows L arranged closely to each other are referred to as a nozzle group.

[0028] The first ejection unit 29 has a first nozzle group G1 to a fourth nozzle group G4. The first nozzle group G1 includes a first nozzle row L1 and a second nozzle row L2. The second nozzle group G2 includes a third nozzle row L3 and a fourth nozzle row L4. The third nozzle group G3 includes a fifth nozzle row L5 and a sixth nozzle row L6. The fourth nozzle group G4 includes a seventh nozzle row L7 and an eighth nozzle row L8. The first nozzle group G1 to the fourth nozzle group G4 may be arranged at equal intervals in the scanning direction Dx.

[0029] The printing unit 18 may eject the same type of liquid from all of the nozzles 27. The printing unit 18 may eject the same type of liquid in any unit, such as for each ejection unit, for each nozzle group, or for each nozzle row L.

[0030] The printing unit 18 may eject multiple types of liquid. Different types of liquid are, for example, inks of different colors. For example, the first ejection unit 29 may eject color inks such as magenta, yellow, cyan, black, light cyan, light magenta, gray, and red from the first nozzle row L1 to the eighth nozzle row L8, respectively. The first nozzle row L1 to the eighth nozzle row L8 of the first ejection unit 29 may eject color inks of different colors. For example, the second ejection unit 30 may eject clear ink from the first nozzle row L1 to the fourth nozzle row L4, and white ink from the fifth nozzle row L5 to the eighth nozzle row L8.

[0031] <Liquid receiving part> 2, the liquid receiving unit 19 may be provided, for example, at a position adjacent in the scanning direction Dx to the downstream end of the support unit 15 in the sub-scanning direction Dy. The liquid receiving unit 19 is configured to collect liquid discharged from the printing unit 18 as waste liquid. The waste liquid is liquid that does not contribute to the image recorded on the medium 21.

[0032] The control unit 13 can perform flushing, which causes liquid to be ejected from the multiple nozzles 27, regardless of printing. Flushing is an operation in which liquid is ejected from the nozzles 27 to prevent clogging of the nozzles 27. Flushing may be performed for one or more nozzle rows L at a time, or may be performed for all nozzle rows L at once. When flushing is performed, the printing unit 18 ejects liquid toward the liquid receiving unit 19.

[0033] <Dust discharge amount setting routine> Next, a control method for the liquid ejection device 11 will be described with reference to the flowchart shown in Fig. 4. The idle ejection amount setting routine shown in Fig. 4 is executed, for example, at the timing when print data is acquired.

[0034] The control unit 13 may repeatedly execute the blank discharge amount setting routine to change the blank discharge amount of each nozzle 27 during flushing. The control unit 13 may execute the blank discharge amount setting routine for each of the plurality of nozzles 27 to set the blank discharge amount of each nozzle 27.

[0035] 4, in step S101, the control unit 13 calculates the degree of influence of the light irradiated from the irradiation unit 17 on each nozzle 27. The control unit 13 may calculate the degree of influence using the distance from each nozzle 27 to the irradiation unit 17. The control unit 13 may calculate the degree of influence using the ease with which the liquid hardens. The control unit 13 may calculate the degree of influence using at least one of the distance to the irradiation unit 17 and the ease with which the liquid hardens.

[0036] For example, the clear ink may be an ink that hardens more easily than the colored inks. The first nozzle row L1 to the fourth nozzle row L4 of the second ejection unit 30 that ejects the clear ink are located closer to the irradiation unit 17 than the other nozzle rows L. In this case, the degree of influence on each of the nozzles 27 that form the first nozzle row L1 to the fourth nozzle row L4 of the second ejection unit 30 is greater than the degree of influence on each of the nozzles 27 that form the other nozzle rows L.

[0037] In step S102, the control unit 13 calculates the print discharge amount of each nozzle 27 during printing. The control unit 13 may calculate the print discharge amount using the number of droplets discharged from each nozzle 27. The control unit 13 may also calculate the print discharge amount using the amount per droplet discharged from each nozzle 27. For example, when the amount per droplet is constant, the control unit 13 may use the number of droplets discharged as the print discharge amount.

[0038] In step S103, the control unit 13 executes a first determination. As the first determination, the control unit 13 determines the magnitude of the degree of influence for the nozzle 27 for which the blank discharge amount is set. For example, the control unit 13 may compare the degree of influence calculated in step S101 with a reference degree. If the degree of influence is equal to or greater than the reference degree, step S103 becomes YES, and the control unit 13 proceeds to step S104.

[0039] In step S104, the control unit 13 executes a second determination. As the second determination, the control unit 13 determines whether to perform a printing discharge operation for the first nozzle determined to have a large degree of influence in the first determination. That is, if the print discharge amount calculated in step S102 is zero, the control unit 13 determines that a print discharge operation will not be performed. If the print discharge amount calculated in step S102 is not zero, the control unit 13 determines that a print discharge operation will be performed.

[0040] If it is determined in step S104 that a print discharge operation will not be performed, step S104 becomes NO, and the control unit 13 proceeds to step S105. In step S105, the control unit 13 sets the idling discharge amount to the first idling discharge amount. That is, the control unit 13 sets the idling discharge amount of the second nozzle, for which it was determined in the second determination that a print discharge operation will not be performed, to the first idling discharge amount. The first idling discharge amount is an amount greater than the reference amount.

[0041] If it is determined in step S104 that a print discharge operation is to be performed, step S104 becomes YES, and the control unit 13 proceeds to step S106. In step S106, the control unit 13 executes a third determination. As the third determination, the control unit 13 compares the print discharge amount with a threshold value for the third nozzle for which it has been determined that a print discharge operation will be performed.

[0042] If it is determined that the print discharge amount is equal to or greater than the threshold, step S106 becomes YES, and the control unit 13 proceeds to step S107. In step S107, the control unit 13 sets the idling discharge amount to the second idling discharge amount. That is, the control unit 13 sets the idling discharge amount of the fourth nozzle, whose print discharge amount was determined to be equal to or greater than the threshold in the third determination, to the second idling discharge amount. The second discharge amount is an amount less than the reference amount.

[0043] If it is determined that the print discharge amount is less than the threshold, step S106 becomes NO, and the control unit 13 proceeds to step S108. In step S108, the control unit 13 sets the idle discharge amount to the reference amount. That is, the control unit 13 sets the idle discharge amount of the fifth nozzle, which was determined in the third determination that the print discharge amount is less than the threshold, to the reference amount.

[0044] In step S103, if the degree of influence is smaller than the reference degree, step S103 becomes NO, and the control unit 13 proceeds to step S107. That is, the control unit 13 sets the dummy discharge amount of the sixth nozzle, which was determined to have a small degree of influence in the first determination, to the second dummy discharge amount.

[0045] <Operation of this embodiment> The operation of this embodiment will be described. Based on the degree of influence and the print discharge amount, the control unit 13 changes the idle discharge amount for each nozzle 27 during flushing. The control unit 13 may start printing after setting the idle discharge amount for each nozzle 27, may set the idle discharge amount while printing, or may set the idle discharge amount after printing.

[0046] 2 is located at its home position. When not printing, the carriage 16 waits at the home position. The home position may be located at the upstream end of the area in which the carriage 16 can move in the sub-scanning direction Dy.

[0047] When printing, the control unit 13 moves the carriage 16 as indicated by the two-dot chain arrow in Fig. 2. That is, the carriage 16 moves repeatedly in the scanning direction Dx, the sub-scanning direction Dy, the direction opposite to the scanning direction Dx, and the sub-scanning direction Dy, until it reaches the downstream end in the sub-scanning direction Dy of the area in which the carriage 16 can move.

[0048] The movement of the carriage 16 in the scanning direction Dx or the direction opposite to the scanning direction Dx between movements in the sub-scanning direction Dy is also called “path movement.” The movement of the carriage 16 from the upstream end to the downstream end in the sub-scanning direction Dy is also called “layer movement.”

[0049] The printing unit 18 may perform printing by ejecting liquid to form multiple layers on the medium 21. The control unit 13 may perform layer movement multiple times to form multiple layers on the medium 21. In this embodiment, the control unit 13 performs printing by performing layer movement three times on one medium 21.

[0050] The printing associated with the first layer movement is also referred to as the first printing. In the first printing, the control unit 13 causes the printing unit 18 to eject, for example, white ink and causes the irradiation unit 17 to irradiate light. As a result of the first printing, a first layer of cured white ink is formed on the medium 21. When the first printing is completed, the control unit 13 moves the carriage 16 in the direction opposite to the sub-scanning direction Dy and returns it to the upstream end in the sub-scanning direction Dy.

[0051] The printing performed during the second layer movement is also referred to as the second printing. During the second printing, the control unit 13 causes the printing unit 18 to eject, for example, color ink and causes the irradiation unit 17 to irradiate light. The second printing forms a second layer of cured color ink on top of the first layer. When the second printing is complete, the control unit 13 moves the carriage 16 in the direction opposite to the sub-scanning direction Dy and returns it to the upstream end in the sub-scanning direction Dy.

[0052] The printing associated with the third layer movement is also referred to as the third printing. In the third printing, the control unit 13 causes the printing unit 18 to eject, for example, transparent ink, and causes the irradiation unit 17 to irradiate light. By the third printing, a third layer, in which the transparent ink is cured, is formed on top of the second layer.

[0053] The control unit 13 may perform flushing when printing is completed. The control unit 13 may perform flushing when the first, second, and third printings are completed. The control unit 13 causes the nozzles 27 to eject a set amount of liquid while the printing unit 18 faces the liquid receiving unit 19. When flushing is completed, the control unit 13 moves the carriage 16 to the home position.

[0054] <Effects of this embodiment> The effects of this embodiment will be described. (1-1) The control unit 13 changes the idle discharge volume of each nozzle 27 based on the degree of influence of light and the print discharge volume. For example, a nozzle 27 with a large print discharge volume will still discharge affected liquid during printing, even if the degree of influence of light is large. In other words, after printing, liquid affected by light is less likely to remain in a nozzle 27 with a large print discharge volume. Therefore, by performing flushing while taking into account the degree of influence of light and the print discharge volume, the amount of liquid consumed during flushing can be reduced.

[0055] (1-2) The control unit 13 sets the idle discharge amount of the second nozzle, which is highly affected by light and does not perform a discharge operation during printing, to a first idle discharge amount that is greater than the reference amount. This allows the liquid that is significantly affected by light to be discharged by flushing, reducing the risk of discharge defects.

[0056] (1-3) The control unit 13 reduces the amount of idle discharge from the fourth nozzle, which has a large print discharge amount, to be less than the amount of idle discharge from the fifth nozzle, which has a small print discharge amount. By reducing the amount of idle discharge from the fourth nozzle, where liquid affected by light is less likely to remain, the amount of liquid consumed by flushing can be reduced while reducing the risk of ejection defects.

[0057] (1-4) The control unit 13 sets the idle discharge amount of the sixth nozzle, which is less affected by light, to the second idle discharge amount, which is less than the reference amount, thereby reducing the amount of liquid consumed during flushing. (1-5) The degree of influence is calculated using the distance from each nozzle 27 to the irradiation unit 17. For example, a nozzle 27 close to the irradiation unit 17 is more likely to be directly affected by light leaking from the irradiation unit 17. Therefore, by using the distance from the nozzle 27 to the irradiation unit 17, the degree of influence can be easily calculated.

[0058] (1-6) The degree of influence is calculated using the ease with which the liquid discharged from the nozzle 27 hardens. Liquids that harden easily are significantly affected even by a small amount of light. By using the ease with which the liquid hardens, the accuracy of the degree of influence can be improved.

[0059] (1-7) When printing is completed, the control unit 13 executes flushing. Therefore, by executing flushing, the liquid that has been affected by light during printing can be discharged.

[0060] [Example of change] This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0061] The control unit 13 may set the dummy discharge amount in multiple steps. For example, the control unit 13 may set the first dummy discharge amount based on the print discharge amount associated with the first print, and then perform the first print. Subsequently, the control unit 13 may set the second dummy discharge amount based on the print discharge amount associated with the second print, and then perform the second print.

[0062] For example, after the first printing, the control unit 13 may set the first dummy discharge amount based on the print discharge amount associated with the first printing. Subsequently, after the second printing, the control unit 13 may set the second dummy discharge amount based on the print discharge amount associated with the second printing.

[0063] The control unit 13 may perform flushing after performing multiple printing operations. The amount of blank discharge to be discharged from each nozzle 27 during flushing may be the total of the blank discharge amounts set for multiple operations, such as the first blank discharge amount and the second blank discharge amount, or may be the larger of the two.

[0064] The control unit 13 may execute flushing when one layer is formed. The control unit 13 may execute flushing between printing passes. The control unit 13 executes flushing when one layer is formed. Therefore, by executing flushing, the liquid that has been affected by light as the layer is formed can be discharged.

[0065] The control unit 13 may execute a first flushing operation when the first printing operation is completed. The control unit 13 may execute a second flushing operation when the second printing operation is completed. The idle discharge amount of each nozzle 27 during the first flushing operation may be set based on the print discharge amount associated with the first printing operation. The idle discharge amount of each nozzle 27 during the second flushing operation may be set based on the print discharge amount associated with the second printing operation.

[0066] The control unit 13 may set the idle ejection amounts for multiple flushing operations all at once before printing. Before printing one cycle, the control unit 13 may set the idle discharge amount based on the print discharge amount for the next cycle of printing. After setting the idle discharge amount for the first flushing, the control unit 13 may execute the first cycle of printing and the first flushing. After setting the idle discharge amount for the second flushing, the control unit 13 may execute the second cycle of printing and the second flushing.

[0067] After one printing run, the control unit 13 may set the dummy discharge amount based on the print discharge amount associated with the immediately preceding printing run. The control unit 13 may set the dummy discharge amount for the first flushing run after the first printing run is completed and before the first flushing run is performed. The control unit 13 may set the dummy discharge amount for the second flushing run after the second printing run is completed and before the second flushing run is performed.

[0068] The liquid ejection device 11 may include a plurality of liquid receiving portions 19. The liquid receiving portions 19 may be provided on both sides of the support portion 15 in the scanning direction Dx. Each liquid receiving portion 19 may be provided across the sub-scanning direction Dy.

[0069] The control unit 13 may perform flushing after moving the carriage 16 in the scanning direction Dx. The control unit 13 may perform flushing between pass movements. The control unit 13 performs flushing after moving the printing unit 18 together with the carriage 16 in the scanning direction Dx. Therefore, by performing flushing, the liquid that has been affected by light while moving in the scanning direction Dx can be discharged.

[0070] The printing unit 18 may perform one printing pass by moving one pass. The control unit 13 may alternately perform one printing pass and one flushing pass. The idle discharge amount of each nozzle 27 during flushing may be set based on the print discharge amount associated with one printing pass before flushing.

[0071] The control unit 13 may set the idle ejection amounts for multiple flushing operations all at once before printing. Before printing one cycle, the control unit 13 may set the idle discharge amount based on the print discharge amount for the next cycle of printing. After setting the idle discharge amount for the first flushing, the control unit 13 may execute the first cycle of printing and the first flushing. After setting the idle discharge amount for the second flushing, the control unit 13 may execute the second cycle of printing and the second flushing.

[0072] After one printing run, the control unit 13 may set the dummy discharge amount based on the print discharge amount associated with the immediately preceding printing run. The control unit 13 may set the dummy discharge amount for the first flushing run after the first printing run is completed and before the first flushing run is performed. The control unit 13 may set the dummy discharge amount for the second flushing run after the second printing run is completed and before the second flushing run is performed.

[0073] The control unit 13 may execute flushing when the carriage 16 moves back and forth in the scanning direction Dx. The idle discharge amount of each nozzle 27 during flushing may be set based on the print discharge amount discharged from each nozzle 27 onto the medium 21 during the reciprocating movement before flushing.

[0074] The degree of influence of the light emitted from the irradiation unit 17 on each nozzle 27 may be calculated in advance and stored, for example, in a memory unit (not shown). The degree of influence may be set taking into account the influence of light reflected by the medium 21, etc. The degree of influence may be stored in association with the type of medium 21. The degree of influence may be set to be high for nozzles 27 that are prone to clogging and low for nozzles 27 that are not prone to clogging, based on the results of experiments in which printing is performed on the medium 21. The control unit 13 may acquire the degree of influence stored in the memory unit in step S101 shown in FIG. 4.

[0075] The control unit 13 may collectively calculate the degree of influence on some of the nozzles 27 out of the multiple nozzles 27. Specifically, the control unit 13 may calculate the degree of influence on each nozzle 27 for each nozzle row L. That is, the degree of influence on each nozzle 27 constituting one nozzle row L may be the same. Similarly, the control unit 13 may calculate the degree of influence on each nozzle 27 for each nozzle group. The control unit 13 may calculate the degree of influence on each nozzle 27 for each ejection unit. The control unit 13 may calculate the degree of influence on each nozzle 27 for each nozzle 27 that ejects the same type of liquid.

[0076] The liquid ejection device 11 may store the degree of influence of light emitted from the irradiation unit 17, the print ejection amount, and the dummy ejection amount in association with each other. The dummy ejection amount may be stored as a matrix indicated by the degree of influence and the dummy ejection amount. The control unit 13 may acquire the stored dummy ejection amount based on the degree of influence and the dummy ejection amount.

[0077] The printing unit 18 may not include the second ejection unit 30. The printing unit 18 may complete printing by forming one layer on the medium 21. The control unit 13 may not execute at least one of the first, second, and third determinations.

[0078] The irradiation unit 17 may be provided separately from the carriage 16. The liquid ejection device 11 may include a first carriage that moves the printing unit 18 and a second carriage that moves the irradiation unit 17. The irradiation unit 17 may be fixed.

[0079] The second dummy discharge amount may be zero. In other words, the fourth nozzle, which has a large degree of influence on the nozzle 27 by light and a print discharge amount equal to or greater than the threshold, may not discharge liquid when flushing the other nozzles 27. The sixth nozzle, which has a small degree of influence on the nozzle 27 by light, may not discharge liquid when flushing the other nozzles 27.

[0080] The liquid ejection device 11 may be a serial printer, a lateral printer, a line printer, a page printer, or the like. The liquid ejection device 11 may be a liquid ejection device that ejects or discharges liquids other than ink. The liquid ejected as minute droplets from the liquid ejection device may be in the form of granules, tears, or strings. The liquid referred to here may be any material that can be ejected from the liquid ejection device. For example, the liquid may be in any liquid phase, including fluids such as high or low viscosity liquids, sols, gel water, other inorganic solvents, organic solvents, solutions, liquid resins, liquid metals, and metal melts. The liquid may refer not only to a single state of matter, but also to solid functional material particles, such as pigments and metal particles, dissolved, dispersed, or mixed in a solvent. Typical examples of liquids include inks and liquid crystals, as described in the above embodiments. Here, ink encompasses various liquid compositions, such as general water-based inks and oil-based inks, as well as gel inks and hot-melt inks. Specific examples of liquid ejection devices include devices that eject liquids containing dispersed or dissolved materials such as electrode materials and color materials used in the manufacture of liquid crystal displays, electroluminescent displays, surface-emitting displays, and color filters. The liquid ejection device may be a device that ejects bioorganic materials used in biochip manufacture, a device used as a precision pipette to eject sample liquids, a textile printing device, a microdispenser, or the like. The liquid ejection device may be a device that ejects lubricating oil with pinpoint accuracy onto precision machinery such as watches and cameras, or a device that ejects transparent resin liquids such as ultraviolet-curing resins onto substrates to form micro-hemispherical lenses, optical lenses, and the like used in optical communication elements. The liquid ejection device may also be a device that ejects etching liquids such as acids or alkalis to etch substrates, etc.

[0081] [Definition] The phrase "at least one" as used herein means "one or more" of the desired options. As an example, the phrase "at least one" as used herein means "only one option" or "both of two options" when the number of options is two. As another example, the phrase "at least one" as used herein means "only one option," "any combination of two options," or "any combination of three or more options" when the number of options is three or more.

[0082] [Note] The technical concepts and effects that can be understood from the above-described embodiment and modified examples will be described below.

[0083] (A) A liquid ejection device includes a printing unit that prints on a medium by ejecting liquid from multiple nozzles, an irradiation unit that hardens the ejected liquid by irradiating it with light, and a control unit, wherein the control unit is capable of performing flushing, in which the liquid is ejected from the multiple nozzles independently of the printing, and changes the amount of empty ejection from each nozzle during the flushing based on the degree of effect on each nozzle of the light irradiated from the irradiation unit and the print ejection amount from each nozzle during the printing.

[0084] According to this configuration, the control unit changes the idle discharge volume of each nozzle based on the degree of light influence and the print discharge volume. For example, a nozzle with a large print discharge volume will still discharge the affected liquid during printing, even if the degree of light influence is large. In other words, after printing, the liquid affected by light is less likely to remain in a nozzle with a large print discharge volume. Therefore, by performing flushing while taking into account the degree of light influence and the print discharge volume, the amount of liquid consumed during flushing can be reduced.

[0085] (B) In the liquid ejection device described in (A), the control unit may perform a first determination to determine the degree of influence for multiple nozzles, and a second determination to determine whether to perform an ejection operation in the printing for a first nozzle determined in the first determination to have a large degree of influence, and may set the idle ejection amount for a second nozzle determined in the second determination not to perform the ejection operation to a first idle ejection amount that is greater than a reference amount.

[0086] With this configuration, the control unit sets the idle discharge amount of the second nozzle, which is highly affected by light and does not perform a discharge operation during printing, to a first idle discharge amount that is greater than the reference amount, thereby making it possible to flush the liquid that has been significantly affected by light and reducing the risk of discharge defects.

[0087] In the liquid ejection device described in (C)(B), the control unit may perform a third judgment to compare the print ejection amount with a threshold value for a third nozzle that is judged in the second judgment to be performing the ejection operation, and may set the blank ejection amount of a fourth nozzle that is judged in the third judgment to have a print ejection amount equal to or greater than the threshold value to a second blank ejection amount that is less than the reference amount, and may set the blank ejection amount of a fifth nozzle that is judged in the third judgment to have a print ejection amount less than the threshold value to the reference amount.

[0088] With this configuration, the control unit reduces the amount of idle discharge from the fourth nozzle, which has a large print discharge volume, compared to the amount of idle discharge from the fifth nozzle, which has a small print discharge volume. By reducing the amount of idle discharge from the fourth nozzle, where liquid affected by light is less likely to remain, it is possible to reduce the amount of liquid consumed during flushing while reducing the risk of ejection defects.

[0089] (D) In ​​the liquid ejection device described in (A) to (C), the control unit may perform a first determination to determine the degree of influence for multiple nozzles, and set the blank ejection amount of a sixth nozzle that is determined to have a small degree of influence in the first determination to a second blank ejection amount that is smaller than the reference amount.

[0090] With this configuration, the control unit sets the idle discharge amount of the sixth nozzle, which is less affected by light, to the second idle discharge amount, which is less than the reference amount, thereby reducing the amount of liquid consumed during flushing.

[0091] (E) In the liquid ejection device described in (A) to (D), the degree of influence may be calculated using the distance from each of the nozzles to the irradiation unit. With this configuration, the degree of influence is calculated using the distance from each nozzle to the irradiation unit. For example, nozzles close to the irradiation unit are more likely to be directly affected by light leaking from the irradiation unit. Therefore, by using the distance from the nozzle to the irradiation unit, the degree of influence can be easily calculated.

[0092] (F) In the liquid ejection device described in (A) to (E), the degree of influence may be calculated using the ease with which the liquid hardens. According to this configuration, the degree of influence is calculated using the ease with which the liquid ejected from the nozzle hardens. Liquids that harden easily are significantly affected even by a small amount of light. By using the ease with which the liquid hardens, the accuracy of the degree of influence can be improved.

[0093] (G) In the liquid ejection device described in (A) to (F), the control unit may execute the flushing when the printing is completed. According to this configuration, the control unit executes flushing when printing is completed, thereby discharging the liquid that has been affected by light during printing.

[0094] (H) In the liquid ejection device described in (A) to (F), the printing unit may perform the printing by ejecting the liquid to form multiple layers on the medium, and the control unit may perform the flushing when one of the layers is formed.

[0095] According to this configuration, the control unit executes flushing when one layer is formed, thereby discharging the liquid that has been affected by light as the layer is formed.

[0096] (I) The liquid ejection device described in (A) to (F) may further include a carriage that can move the printing unit in a scanning direction, and the control unit may perform the flushing after moving the carriage in the scanning direction.

[0097] With this configuration, the control unit performs flushing after moving the printing unit together with the carriage in the scanning direction, thereby discharging the liquid that has been affected by light while moving in the scanning direction.

[0098] (J) A method for controlling a liquid ejection device includes a printing unit that prints on a medium by ejecting liquid from a plurality of nozzles, and an irradiation unit that hardens the ejected liquid by irradiating it with light, and the method calculates the degree of influence of light irradiated from the irradiation unit on each of the nozzles, calculates the print ejection amount of each of the nozzles in the printing, and changes the idle ejection amount of each of the nozzles in flushing, which ejects the liquid from the plurality of nozzles regardless of the printing, based on the degree of influence and the print ejection amount.

[0099] According to this method, it is possible to achieve the same effects as those of the liquid ejection device. [Explanation of symbols]

[0100] 11...liquid ejection device, 12...housing, 13...control unit, 15...support unit, 16...carriage, 17...irradiation unit, 18...printing unit, 19...liquid receiving unit, 21...medium, 23...movement mechanism, 24...horizontal axis, 25...vertical axis, 27...nozzle, 29...first ejection unit, 30...second ejection unit, 32...nozzle surface, Dx...scanning direction, Dy...sub-scanning direction, G1 to G4...first nozzle group to fourth nozzle group, L...nozzle row, L1 to L8...first nozzle row to eighth nozzle row.

Claims

1. a printing unit that prints on a medium by ejecting liquid from a plurality of nozzles; an irradiation unit that irradiates light to harden the ejected liquid; A control unit; Equipped with The control unit a flushing process in which the liquid is ejected from the plurality of nozzles can be performed independently of the printing process; A liquid ejection device characterized by changing the amount of idle ejection from each nozzle during flushing based on the degree of influence on each nozzle by the light irradiated from the irradiation unit and the printing ejection amount from each nozzle during printing.

2. The control unit performing a first determination of the degree of influence for the plurality of nozzles; a second determination is made to determine whether to perform a discharge operation in the printing for the first nozzle determined to have a large degree of influence in the first determination; 2. The liquid ejection device according to claim 1, wherein the idle ejection amount of the second nozzle for which it has been determined in the second determination that the ejection operation will not be performed is set to a first idle ejection amount that is greater than a reference amount.

3. The control unit a third determination is performed for a third nozzle determined in the second determination to perform the ejection operation, in which the print ejection amount is compared with a threshold value; the idling discharge amount of the fourth nozzle determined in the third determination to be equal to or greater than the threshold value is set to a second idling discharge amount that is less than the reference amount; The liquid ejection device according to claim 2 , wherein the idle ejection amount of a fifth nozzle, which is determined in the third determination that the print ejection amount is less than the threshold value, is set to the reference amount.

4. The control unit performing a first determination of the degree of influence for the plurality of nozzles; A liquid ejection device according to any one of claims 1 to 3, characterized in that the idle ejection amount of the sixth nozzle, which is determined to have a small degree of influence in the first judgment, is set to a second idle ejection amount which is smaller than the reference amount.

5. The liquid ejection device according to claim 1 , wherein the degree of influence is calculated using a distance from each of the nozzles to the irradiation unit.

6. The liquid ejection apparatus according to claim 5 , wherein the degree of influence is calculated using the ease with which the liquid hardens.

7. The liquid ejection apparatus according to claim 1 , wherein the control unit executes the flushing when the printing is completed.

8. the printing unit performs the printing by ejecting the liquid to form a plurality of layers on the medium; The liquid ejection apparatus according to claim 1 , wherein the control unit executes the flushing when one of the layers is formed.

9. a carriage that can move the printing unit in a scanning direction; The liquid ejection apparatus according to claim 1 , wherein the control unit executes the flushing after moving the carriage in the scanning direction.

10. a printing unit that prints on a medium by ejecting liquid from a plurality of nozzles; an irradiation unit that irradiates light to harden the ejected liquid; A method for controlling a liquid ejection device comprising: calculating a degree of influence of light irradiated from the irradiation unit on each of the nozzles; calculating a print ejection amount of each of the nozzles during the printing; A method for controlling a liquid ejection device, characterized in that the amount of idle ejection of each nozzle during flushing, in which the liquid is ejected from multiple nozzles regardless of the printing, is changed based on the degree of influence and the printing ejection amount.

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