Liquid discharge device and liquid discharge method

Abstract

To solve a problem in which there is risk that waving or wrinkles may occur due to excessive water absorption by a sheet in a configuration in which liquid containing water is directly discharged to the sheet so as to prevent scattering of paper powder, and additionally, increases in size and cost of a device are caused because a discharge section for discharging transparent liquid containing at least water to the sheet is provided separately from a recording head for performing recording on the sheet.SOLUTION: A control section of a liquid discharge device can execute, as control for discharging liquid from a liquid discharge section, first discharge control for performing recording on a medium, second discharge control for performing maintenance of the liquid discharge section, which is control different from the first discharge control, and third discharge control for turning liquid into mist between the liquid discharge section and a support section, which is control different from the first discharge control and the second discharge control. Furthermore, when the third discharge control is executed, the control section executes the third discharge control before the medium is fed between the support section and the liquid discharge section.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a liquid ejection device that ejects and records a liquid onto a medium. The present invention also relates to a liquid ejection method for a liquid ejection device.

Background Art

[0002] The inkjet recording device described in Patent Document 1 includes a discharge unit that discharges at least a transparent liquid containing water onto a sheet of paper, separately from a recording head that performs recording on the sheet of paper, for the purpose of suppressing clogging of nozzles due to paper dust.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a configuration such as the inkjet recording device described in Patent Document 1, in which a liquid containing water is directly ejected onto a sheet of paper to suppress the scattering of paper dust, there is a risk that the sheet of paper may absorb water excessively, causing undulations and wrinkles, which may have an adverse effect on the recording quality. In addition, providing a discharge unit that discharges at least a transparent liquid containing water onto the sheet of paper, separately from the recording head that performs recording on the sheet of paper, leads to an increase in the size and cost of the device.

Means for Solving the Problems

[0005] To solve the above problems, the liquid ejection device of the present invention includes a support portion that supports a medium, a liquid ejection portion having a plurality of nozzles that eject liquid onto the medium supported by the support portion, a conveyance portion that conveys the medium between the support portion and the liquid ejection portion, and a control portion that controls the liquid ejection portion and the conveyance portion. The control portion is capable of executing, as control for ejecting liquid from the liquid ejection portion, a first ejection control for performing recording on the medium, a second ejection control that is different from the first ejection control and is for maintaining the liquid ejection portion, and a third ejection control that is different from the first ejection control and the second ejection control and is for atomizing liquid between the liquid ejection portion and the support portion. Further, when the control portion executes the third ejection control, the control portion executes the third ejection control before feeding the medium between the support portion and the liquid ejection portion.

[0006] Also, a liquid ejection method of the liquid ejection device of the present invention is a liquid ejection method in a liquid ejection device including a support portion that supports a medium, a liquid ejection portion having a plurality of nozzles that eject liquid onto the medium supported by the support portion, and a conveyance portion that conveys the medium between the support portion and the liquid ejection portion. As a process of ejecting liquid from the liquid ejection portion, the method is capable of executing a first ejection process for performing recording on the medium, a second ejection process that is different from the first ejection process and is for maintaining the liquid ejection portion, and a third ejection process that is different from the first ejection process and the second ejection process and is for atomizing liquid between the liquid ejection portion and the support portion. When the third ejection process is executed, the third ejection process is executed before feeding the medium between the support portion and the liquid ejection portion.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0008] Hereinafter, the present invention will be schematically described. The liquid ejection device according to the first aspect includes a support unit that supports a medium, a liquid ejection unit having a plurality of nozzles that eject liquid onto the medium supported by the support unit, a conveyance unit that sends the medium between the support unit and the liquid ejection unit, and a control unit that controls the liquid ejection unit and the conveyance unit. The control unit, as control for ejecting liquid from the liquid ejection unit, includes a first ejection control for performing recording on the medium, a second ejection control that is a control different from the first ejection control and is for maintaining the liquid ejection unit, and a third ejection control that is a control different from the first ejection control and the second ejection control and is for atomizing liquid between the liquid ejection unit and the support unit. The control unit is further characterized in that when executing the third ejection control, the third ejection control is executed before sending the medium between the support unit and the liquid ejection unit.

[0009] According to this aspect, the humidity on the support unit can be increased by the third ejection control, thereby suppressing the fine particles adhering to the medium from rising and adhering to the nozzles. And in order to obtain such an effect, a configuration for ejecting liquid separately from the liquid ejection unit becomes unnecessary, and an increase in the size and cost of the device can be suppressed. Examples of the fine particles include dust and the like, and when the medium is paper, paper powder is included.

[0010] The second aspect is an aspect dependent on the first aspect, comprising humidity detection means for detecting the humidity inside the apparatus, and when the humidity acquired by the humidity detection means is lower than a predetermined threshold value, the control unit executes the third discharge control. According to this aspect, when the humidity exceeds the threshold value, that is, in a high-humidity environment where fine particles adhering to the medium are difficult to fly up, the third discharge control is not performed, so that liquid consumption can be suppressed.

[0011] The third aspect is an aspect dependent on the first aspect, and when the control unit performs the first discharge control, it can switch between discharging a liquid that realizes a first quality and discharging a liquid that realizes a second quality that is higher in definition than the first quality. Further, when the control unit realizes the first quality, it does not execute the third discharge control, and when it realizes the second quality, it executes the third discharge control.

[0012] When realizing the second quality that is relatively higher in definition than the first quality, dot missing is likely to be noticeable. According to this aspect, when realizing the first quality, the third discharge control is not executed, and when realizing the second quality, the third discharge control is executed, so that the second quality can be appropriately realized. Further, when realizing the first quality, since the third discharge control is not executed, liquid consumption can be suppressed.

[0013] The fourth aspect is an aspect dependent on the first aspect, and when the control unit performs recording on a first medium and a second medium following the first medium, the first medium is located downstream in the conveyance direction between the liquid discharge unit and the support unit, and the second medium is located upstream in the conveyance direction between the liquid discharge unit and the support unit, and the third discharge control is executed.

[0014] According to this aspect, when recording on a plurality of media, it is possible to suppress fine particles adhering to the media from flying up and adhering to the nozzles. Furthermore, this aspect is not limited to the first aspect, and may be subordinate to the second or third aspect.

[0015] The fifth aspect is an aspect subordinate to the first aspect, characterized in that the control unit executes the third discharge control using the time from when the recording data is received until the leading edge of the medium first fed reaches between the support unit and the liquid discharge unit.

[0016] According to this aspect, since the third discharge control is executed using the time from when the recording data is received until the leading edge of the medium first fed reaches between the support unit and the liquid discharge unit, a decrease in the recording throughput associated with executing the third discharge control can be suppressed. Furthermore, this aspect is not limited to the first aspect, and may be subordinate to any one of the second to fourth aspects.

[0017] The sixth aspect is an aspect subordinate to any one of the first to fifth aspects, characterized in that the droplets discharged in the third discharge control are smaller than the droplets discharged in the first discharge control and the droplets discharged in the second discharge control.

[0018] According to this aspect, since the droplets discharged in the third discharge control are smaller than the droplets discharged in the first discharge control and the droplets discharged in the second discharge control, the humidity on the support unit can be appropriately increased when the third discharge control is executed.

[0019] The seventh aspect is an aspect subordinate to the first aspect, characterized in that the distance between the liquid discharge unit and the support unit is configured to be adjustable under the control of the control unit, and the control unit makes the distance when executing the third discharge control larger than the distance when executing the first discharge control.

[0020] According to this aspect, when the control unit executes the third ejection control, the interval is made larger than the interval when the first ejection control is executed. As a result, droplets are more likely to be atomized between the liquid ejection unit and the support unit, and the humidity on the support unit can be appropriately increased. Note that this aspect is not limited to the first aspect described above, and may be subordinate to any of the second to sixth aspects.

[0021] The eighth aspect is an aspect subordinate to the second aspect, and includes temperature detection means for detecting the temperature inside the apparatus. When the temperature is the first temperature, the threshold value is the first threshold value, and when the temperature is higher than the first temperature, the threshold value is the second threshold value. The first threshold value is lower than the second threshold value, and the control unit uses the threshold value corresponding to the temperature detected by the temperature detection means.

[0022] The amount of moisture contained in the air increases as the temperature rises even at the same relative humidity. Therefore, the need for humidification decreases as the temperature increases. In this aspect, since the first threshold value is lower than the second threshold value, unnecessary humidification can be suppressed and the liquid consumption can be suppressed. Note that this aspect is not limited to the second aspect described above, and may be subordinate to any of the third to seventh aspects including the configuration of the second aspect.

[0023] The ninth aspect is an aspect subordinate to the first aspect, and includes humidity detection means for detecting the humidity inside the apparatus. When the humidity is the first humidity, the liquid ejection amount in the third ejection control is the first ejection amount, and when the humidity is the second humidity lower than the first humidity, the liquid ejection amount in the third ejection control is the second ejection amount. The second ejection amount is larger than the first ejection amount, and the control unit uses the liquid ejection amount corresponding to the humidity detected by the humidity detection means in the third ejection control.

[0024] According to this aspect, in the third discharge control, since the control unit uses the liquid discharge amount corresponding to the humidity detected by the humidity detection means, an appropriate liquid discharge amount corresponding to the humidity is used. Thereby, the humidity on the support part can be appropriately increased. Note that this aspect is not limited to the first aspect, and may be subordinate to any of the second to eighth aspects.

[0025] The tenth aspect is an aspect subordinate to the first aspect, wherein the liquid discharge unit is configured to be able to discharge liquids of a plurality of colors from different nozzles, and the control unit executes the third discharge control using the liquid of the color with the largest water content among the liquids of the plurality of colors.

[0026] According to this aspect, since the control unit executes the third discharge control using the liquid of the color with the largest water content among the liquids of the plurality of colors, the humidity on the support part can be appropriately increased. Note that "having a large water content" means that the ratio of the weight of water occupied per unit weight of the liquid or the ratio of the volume of water occupied per unit volume of the liquid is large. Note that this aspect is not limited to the first aspect, and may be subordinate to any of the second to ninth aspects.

[0027] The eleventh aspect is an aspect subordinate to the first aspect, wherein the liquid discharge unit is configured to be able to discharge liquids of a plurality of colors including yellow from different nozzles, and the control unit executes the third discharge control using the yellow liquid among the liquids of the plurality of colors.

[0028] When the liquid becomes mist and floats and adheres to the components in the device, that part is likely to stand out as dirt. According to this aspect, since the control unit executes the third discharge control using the yellow liquid among the liquids of the plurality of colors, even if the liquid adheres to the components in the device, it can be made less noticeable as dirt. Note that this aspect is not limited to the first aspect, and may be subordinate to any of the second to ninth aspects.

[0029] Aspect 12 is an aspect dependent on Aspect 1, wherein the control unit executes the third discharge control using the nozzle among the plurality of nozzles having a long non-discharge period.

[0030] According to this aspect, since the control unit executes the third discharge control using the nozzle among the plurality of nozzles having a long non-discharge period, clogging of the nozzle can be suppressed. Note that this aspect is not limited to the above Aspect 1, and may be dependent on any of the above Aspects 3 to 9.

[0031] The liquid discharge method according to Aspect 13 is a liquid discharge method in a liquid discharge apparatus including a support unit that supports a medium, a liquid discharge unit that includes a plurality of nozzles that discharge liquid onto the medium supported by the support unit, and a conveyance unit that conveys the medium between the support unit and the liquid discharge unit. As a process of discharging liquid from the liquid discharge unit, a first discharge process for performing recording on the medium, a second discharge process that is a process different from the first discharge process and for maintaining the liquid discharge unit, and a third discharge process that is a process different from the first discharge process and the second discharge process and for atomizing the liquid between the liquid discharge unit and the support unit can be executed. When the third discharge process is executed, the third discharge process is executed before feeding the medium between the support unit and the liquid discharge unit.

[0032] According to this aspect, the humidity on the support unit can be increased by the third discharge process, thereby suppressing fine substances adhering to the medium from rising and adhering to the nozzle. And in order to obtain such an operational effect, a configuration for discharging liquid separately from the liquid discharge unit becomes unnecessary, and an increase in the size and cost of the apparatus can be suppressed.

[0033] Hereinafter, the present invention will be specifically described. Hereinafter, an inkjet printer 1 that performs recording by ejecting ink, which is an example of a liquid, onto a medium typified by recording paper will be described as an example of a liquid ejecting device. Hereinafter, the inkjet printer 1 will be abbreviated as the printer 1.

[0034] The X - Y - Z coordinate system shown in each figure is a rectangular coordinate system. The Y - axis direction is the width direction that intersects the conveyance direction of the medium and is also the depth direction of the apparatus. Among the side surfaces constituting the periphery of the apparatus main body 2 in the present embodiment, the side surface in the +Y direction is the back surface, and the side surface in the -Y direction is the front surface. The X - axis direction is the width direction of the apparatus. When viewed from the operator of the printer 1, the +X direction is the left side and the -X direction is the right side. Also, the -X direction is the medium feeding direction from each of the medium cassettes described later. The Z - axis direction is the vertical direction, that is, the apparatus height direction. The +Z direction is the upward direction and the -Z direction is the downward direction. Hereinafter, the direction in which the medium is being sent may be referred to as "downstream", and the opposite direction may be referred to as "upstream". In FIG. 1, the medium conveyance path is indicated by a broken line. In the printer 1, the medium is conveyed through the medium conveyance path indicated by the broken line.

[0035] The printer 1 includes a plurality of medium cassettes, specifically, a first medium cassette 3, a second medium cassette 4, a third medium cassette 5, and a fourth medium cassette 6, along the vertical direction below the apparatus main body 2 provided with a line head 12 described later. The symbol P indicates the medium accommodated in each medium cassette. For each medium cassette, a pick - up roller for feeding the accommodated medium in the -X direction is provided. The symbols 21, 22, 23, and 24 indicate the pick - up rollers provided for each medium cassette. Also, for each medium cassette, a pair of feed rollers for further feeding the medium fed out by the pick - up roller downstream is provided. The symbols 25, 26, 27, and 28 indicate the pairs of feed rollers provided for each medium cassette. Hereinafter, unless otherwise specified, the "roller pair" shall be composed of a driving roller driven by a power source such as a motor and a driven roller that rotates passively in contact with the driving roller.

[0036] Reference numeral T1 indicates the conveyance path of the medium sent out from each medium cassette and reaching the conveyance roller pair 34. The medium sent out from the first medium cassette 3 is sent to the conveyance roller pair 34 under the feeding force from the conveyance roller pairs 29 and 33. The medium sent out from the second medium cassette 4 is sent to the conveyance roller pair 34 under the feeding force from the conveyance roller pairs 30, 29, and 33. The medium sent out from the third medium cassette 5 is sent to the conveyance roller pair 34 under the feeding force from the conveyance roller pairs 31, 30, 29, and 33. The medium sent out from the fourth medium cassette 6 is sent to the conveyance roller pair 34 under the feeding force from the conveyance roller pairs 32, 31, 30, 29, and 33.

[0037] The medium receiving the feeding force from the conveyance roller pair 34 is sent between the line head 12, which is an example of a liquid ejection unit, and the conveyance belt 53, that is, to the recording position facing the line head 12. The conveyance roller pair 34 constitutes a conveyance unit that conveys the medium between the line head 12 and the conveyance belt 53. The line head 12 ejects ink, which is an example of a liquid, onto the surface of the medium to perform recording. The line head 12 is an ink ejection head in which a plurality of nozzles 13 for ejecting ink cover the entire width of the medium, and is configured as an ink ejection head capable of performing recording over the entire width of the medium without moving in the medium width direction. However, the ink ejection head is not limited to this, and it may be of a type mounted on a carriage and ejecting ink while moving in the medium width direction.

[0038] The line head 14 according to the present embodiment employs a piezo element, which is a piezoelectric element whose volume changes when a voltage is applied. By controlling the driving waveform of the piezo element, the movement of the meniscus of the nozzle 13 can be controlled, and the size and ejection speed of the ejected ink droplets can be controlled. Still, in the present embodiment, the plurality of nozzles 13 includes a plurality of nozzles 13 that discharge yellow ink, a plurality of nozzles 13 that discharge magenta ink, a plurality of nozzles 13 that discharge cyan ink, and a plurality of nozzles 13 that discharge magenta ink in the present embodiment.

[0039] Next, the conveyance belt 53 is an endless belt wound around the first roller 54 and the second roller 55, and the first roller 54 rotates when driven by a power source such as a motor. The medium is conveyed to a position facing the line head 12 while being adsorbed on the belt surface of the conveyance belt 53. The first roller 54, the second roller 55, and the conveyance belt 53 constitute a belt unit 52. The belt unit 52 has the first roller 54 as a rotation axis and is provided so as to be rotatable by a power source (not shown). The belt unit 52 is an example of a support portion that supports the medium. Note that the support portion is not limited to a configuration including the conveyance belt 53, and may be, for example, a platen that does not perform a medium conveyance function.

[0040] The medium on which recording has been performed on the first surface by the line head 12 is sent by a pair of conveyance rollers 35 located downstream of the conveyance belt 53 toward either a pair of conveyance rollers 36 or a pair of conveyance rollers 40. A path switching flap (not shown) is provided downstream of the pair of conveyance rollers 35, and the medium receiving a feeding force from the pair of conveyance rollers 35 is sent to either the pair of conveyance rollers 36 or the pair of conveyance rollers 40 by this path switching flap.

[0041] When recording is not performed on the second surface opposite to the first surface of the medium, that is, when duplex recording is not performed, the medium is sent from the pair of conveyance rollers 35 toward the pair of conveyance rollers 36 and discharged toward the discharge tray 8 through the discharge path T4. The discharge path T4 is provided with a pair of conveyance rollers 38 and a pair of conveyance rollers 39.

[0042] When recording is performed on both the first side and the opposite second side of the medium, i.e., when double-sided recording is performed, the medium is sent from the transport roller pair 35 toward the transport roller pair 40 and enters the switchback path T2. Thereafter, the rotation direction of the transport roller pair 40 is switched, the medium enters the inversion path T3, and is sent to the transport roller pair 34 by the transport roller pairs 41, 42, 43.

[0043] Reference numerals 10A and 10B are ink storage portions as liquid storage portions that store ink before ejection. The ink ejected from the line head 12 is supplied from the ink storage portions 10A and 10B to the line head 12 via a tube (not shown). The ink storage portion 10A stores black ink as an example. The ink storage portion 10B stores yellow, magenta, and cyan inks as an example.

[0044] Reference numeral 9 is a cap unit having a cap portion 9a that caps the line head 12. The cap unit 9 is provided so as to be displaceable between a separation position (see FIG. 1) where the cap portion 9a is separated from the line head 12 and a cap position (see FIG. 2) where the cap portion 9a caps the head surface 12a of the line head 12 by a power source (not shown).

[0045] Reference numeral 11 is a waste liquid storage portion that stores ink as waste liquid ejected for maintenance from the line head 12 toward the cap portion 9a. The ink as waste liquid ejected for maintenance from the line head 12 toward the cap portion 9a is sent from the cap portion 9a to the waste liquid storage portion 11 via a tube (not shown).

[0046] The above is an outline of the overall configuration of the printer 1. Hereinafter, the control unit 80 will be described with reference to FIG. 3. The control unit 80 performs various controls including recording control in the printer 1. In FIG. 3, only the components necessary for the following description are shown, and the illustration of other components is omitted. Connected electrically to the control unit 80 as an output system are a feed motor 87, a conveyance motor 88, a head movement motor 89, and a line head 12. The feed motor 87 is a power source for each of the above-described pick rollers and each pair of feed rollers. Also, the conveyance motor 88 is a power source for each of the above-described pairs of conveyance rollers.

[0047] Also, the head movement motor 89 is a power source for moving the line head 12 forward and backward with respect to the conveyance belt 53. That is, the line head 12 is provided so as to be displaceable in the Z-axis direction, that is, in the direction of moving forward and backward with respect to the conveyance belt 53, by a guide portion (not shown). And the line head 12 is configured to move forward and backward with respect to the conveyance belt 53 by a rack and pinion mechanism (not shown) that operates by the power of the head movement motor 89. The above-described rack and pinion mechanism can be composed of, for example, a rack (not shown) provided on the line head 12 and a pinion (not shown) that rotates by the power of the head movement motor 89. The control unit 80 can adjust the distance (reference numeral Pg in FIGS. 5 and 6) between the line head 12 and the conveyance belt 53 by controlling the head movement motor 89. Hereinafter, this distance will be referred to as the gap Pg.

[0048] Each of the above motors is a DC motor as an example. In addition, each of the above motors is provided with a rotary encoder (not shown in the figure), and the control unit 80 can detect the rotation direction, rotation amount, and rotation speed of each of the above motors by this rotary encoder. That is, the control unit 80 can detect the drive direction, drive amount, and drive speed of each drive target.

[0049] Also, connected electrically to the control unit 80 as an input system are an operation panel 95, a medium detection unit 86, and a temperature and humidity sensor 91. The operation panel 95 is a part that accepts turning on and off of the power of the printer 1, various settings, recording execution, etc., and can be composed of, for example, a touch panel in which a user interface is realized under the control of the control unit 80. The media detection unit 86 is disposed between the pair of conveyance rollers 34 and the line head 12 as shown in FIG. 1. The media detection unit 86 is, as an example, an optical sensor including a light emitting unit that emits detection light and a light receiving unit that receives a reflected component of the detection light. The control unit 80 can detect that the leading edge of the media has reached the position of the media detection unit 86 or that the trailing edge of the media has passed the position of the media detection unit 86 based on the detection information of the media detection unit 86. The temperature and humidity sensor 91 serves as both a temperature detection means for detecting the temperature inside the apparatus and a humidity detection means for detecting the humidity inside the apparatus. In the present embodiment, the temperature and humidity sensor 91 is provided on the line head 12, and detects the temperature and humidity around the line head 12 and the conveyance belt 53 facing the line head 12.

[0050] The control unit 80 includes a CPU 81 that executes a computer program, in other words, software execution processing, a volatile memory 82, and a non-volatile memory 83. The CPU 81 performs various calculations necessary for executing the program 84 stored in the non-volatile memory 83. The volatile memory 82 is used as a temporary data storage area. The non-volatile memory 83 stores the program 84 and control parameters 85 necessary for executing the program 84. The program 84 includes programs for executing various processes described later, and the control parameters 85 include parameters for executing the program 84. The various processes described later are realized by the control unit 80 executing the program 84.

[0051] Subsequently, head maintenance will be further described with reference to FIG. 4. When the control unit 80 determines that it is the head maintenance timing (Yes in step S101), it determines whether it is in the cap state (step S102). The cap state is a state in which the cap portion 9a of the cap unit 9 covers the head surface 12a of the line head 12 as shown in FIG. 2. If it is in the cap state (Yes in step S102), the process proceeds to step S105 described later.

[0052] When it is not in the cap state (No in step S102), the control unit 80 retracts the belt unit 52 from the position facing the line head 12 as shown by the change from FIG. 1 to FIG. 2 (step S103). Next, the cap unit 9 is advanced to a position covering the head surface 12a of the line head 12 as shown by the change from FIG. 1 to FIG. 2 (step S104). Then, the control unit 80 performs second ejection control for ejecting ink droplets from the line head 12 (step S105). The second ejection control is an ink ejection operation for the purpose of eliminating clogging of the nozzles 13. Incidentally, when performing this second ejection control, if the cap portion 9a is facing the head surface 12a, the cap portion 9a may be separated from the head surface 12a.

[0053] Incidentally, the head maintenance timing (step S101) can be set to at least one or more of, for example, when the power is turned on, when the power is turned off, when recording data is received, that is, before the start of a recording job, after the start of a recording job, and after a predetermined time has elapsed since the previous maintenance. Also, the size of the ink droplets ejected in the second ejection control (step S105) may be the same as, larger than, or smaller than the size of the ink droplets in the first ejection control described later, that is, the size of the ink droplets when recording is executed. However, in the present embodiment, the size of the ink droplets ejected in the second ejection control is smaller than the size of the ink droplets when the third ejection control described later is executed.

[0054] Next, when the second ejection control is completed, the control unit 80 retracts the cap unit 9 from the position facing the line head 12 as shown by the change from FIG. 2 to FIG. 1 (step S106), and advances the belt unit 52 to the position facing the line head 12 as shown in FIG. 1 (step S107).

[0055] Next, the process performed by the control unit 80 when recording data is received with reference to FIG. 7 will be described. The recording data is transmitted from an external computer connected to the printer 1 to the control unit 80, for example. When the control unit 80 receives the recording data (Yes in step S201), it executes the third ejection control (step S203) in parallel with the medium feeding operation (step S202). The medium feeding operation is an operation of feeding a medium from any one of the first medium cassette 3, the second medium cassette 4, the third medium cassette 5, and the fourth medium cassette 6. The third ejection control is an operation of ejecting ink droplets from the line head 12.

[0056] Hereinafter, the third ejection control (steps S203 and S209) and the first ejection control (step S206) will be described in detail. FIG. 5 is a diagram for explaining the first ejection control. The first ejection control is an ink ejection control when recording on a medium, and ejects ink droplets M1 and lands the ink droplets M1 on the medium. On the other hand, FIG. 6 is a diagram for explaining the third ejection control. The third ejection control is a control different from the above-described first ejection control and second ejection control, and is a control for atomizing ink between the line head 12 and the conveyance belt 53. In FIG. 6, the symbol M2 indicates an ink mist. Regarding the third ejection control, although it will be described in detail later, by executing the third ejection control, the humidity on the conveyance belt 53 can be increased.

[0057] Returning to FIG. 7, when the control unit 80 detects the leading edge of the medium by the medium detection unit 86 (Yes in step S204), it conveys the medium to the recording start position (step S205), executes the first ejection control (step S206), and performs recording on the medium. Then, if there is no next page (No in step S207), the process ends. If there is a next page (Yes in step S207), between the preceding medium and the succeeding medium (in step S208), the third ejection control is executed (step S209). Between the preceding medium and the succeeding medium means that the preceding medium is downstream of the line head 12 and the succeeding medium is upstream of the line head 12. After executing the third ejection control (step S209), the process returns to step S204. Incidentally, in FIG. 7, the ejection process after recording on the medium and the conveyance process in the case of performing double-sided recording are not shown.

[0058] As described above, as control for ejecting ink from the line head 12, the control unit 80 can execute a first ejection control for performing recording on a medium and a second ejection control, which is a control different from the first ejection control and for maintaining the line head 12. Further, the control unit 80 can execute a third ejection control for atomizing ink between the line head 12 and the conveyance belt 53, which is a control different from the first ejection control and the second ejection control. Furthermore, when the control unit 80 executes the third ejection control, it executes the third ejection control before feeding the medium between the conveyance belt 53 and the line head 12. In other words, as a liquid ejection method, the printer 1 can execute a first ejection process for performing recording on a medium and a second ejection process, which is a process different from the first ejection process and for maintaining the line head 12. The printer 1 can also execute a third ejection process for atomizing ink between the line head 12 and the conveyance belt 53, which is a process different from the first ejection process and the second ejection process. When the printer 1 executes the third ejection process, it executes the third ejection process before feeding the medium between the line head 12 and the conveyance belt 53. By the third ejection control or the third ejection process as described above, the humidity on the conveyance belt 53 can be increased, thereby suppressing the fine particles adhering to the medium from rising and adhering to the nozzles 13. In order to obtain such an effect, a configuration for ejecting liquid separately from the line head 12 becomes unnecessary, and an increase in the size and cost of the apparatus can be suppressed.

[0059] Also, in the above embodiment, when the control unit 80 performs recording on a preceding medium, that is, a first medium, and a subsequent medium, that is, a second medium following the first medium, the control unit 80 executes the third ejection control between the preceding medium and the subsequent medium (steps S208 and S209 in FIG. 7). That is, the third ejection control is executed in a state where the first medium is positioned downstream in the conveyance direction between the line head 12 and the conveyance belt 53 and the second medium is positioned upstream in the conveyance direction between the line head 12 and the conveyance belt 53. This can prevent minute substances adhering to the medium from flying up and adhering to the nozzle 13 when recording on a plurality of media.

[0060] Further, the control unit 80 executes third ejection control using the time from when it receives the recording data until the leading end of the medium first fed reaches between the conveyance belt 53 and the line head 12 (steps S202 and S203 in FIG. 7). By executing the third ejection control using the time from when the recording data is received until the leading end of the medium first fed reaches between the conveyance belt 53 and the line head 12, it is possible to suppress a decrease in the recording throughput associated with the execution of the third ejection control.

[0061] Hereinafter, the third ejection control will be further described. First, a method of atomizing the ink ejected by the third ejection control between the line head 12 and the conveyance belt 53 will be described. Atomization of the ink between the line head 12 and the conveyance belt 53 can be achieved by making the ejected ink droplets smaller than the ink droplets ejected in the first ejection control and the ink droplets ejected in the second ejection control. According to such a method, when executing the third ejection control, the humidity on the conveyance belt 53 can be appropriately increased.

[0062] Incidentally, the larger the gap Pg (see FIG. 6), the easier it is for the ejected ink droplets to be atomized without reaching the conveyance belt 53. Therefore, the control unit 80 can atomize the ink between the line head 12 and the conveyance belt 53 by making the gap PG when executing the third ejection control larger than the gap PG when executing the first ejection control. According to such a method, it becomes easier for the ink to be atomized between the line head 12 and the conveyance belt 53, and the humidity on the conveyance belt 53 can be appropriately increased. Incidentally, in addition to increasing the gap Pg in this way, the ink droplets ejected in the third ejection control may be made smaller than the ink droplets ejected in the first ejection control and the ink droplets ejected in the second ejection control. Also, the lower the ejection speed of the ink droplets, the easier it is for the ejected ink droplets to be atomized. Therefore, the ejection speed of the ink droplets when performing the third ejection control may be set lower than the ejection speed of the ink droplets when performing the first ejection control. Also, among increasing the gap Pg, decreasing the ink droplets, and decreasing the ejection speed of the ink droplets as described above, any two or all of them may be adopted.

[0063] Also, the third ejection control may be executed necessarily, or may be executed according to conditions. For example, when executing according to conditions, a determination process as to whether or not to execute the third ejection control is added before steps S203 and S209 in FIG. 7.

[0064] As an example, the control unit 80 may execute the third ejection control only when the humidity acquired by the temperature and humidity sensor 91 is lower than a predetermined threshold value. In this case, when the humidity exceeds the threshold value, that is, in a high humidity environment where fine particles attached to the medium are difficult to fly up, the third ejection control is not performed, so that ink consumption can be suppressed.

[0065] Also, the control unit 80 may be able to switch between ejection of ink that realizes the first quality and ejection of ink that realizes the second quality that is higher definition than the first quality when performing the first ejection control. And in this case, when realizing the first quality, the third ejection control is not executed, and when realizing the second quality, the third ejection control may be executed. As an example, the first quality is displayed as "Normal" in the print quality selection menu on the printer driver, and the second quality is displayed as "High Quality". As an example, the second quality has a higher print resolution than the first quality. That is, when realizing the second quality that is relatively higher definition than the first quality, it is easier for dot missing to be noticeable if it occurs. Therefore, when realizing the first quality, the third ejection control is not executed, and when realizing the second quality, the third ejection control is executed, so that the second quality can be appropriately realized. Also, when realizing the first quality, since the third ejection control is not executed, ink consumption can be suppressed.

[0066] Further, the control unit 80 may determine whether to execute the third ejection control according to the type information of the medium included in the received recording data. Dot missing caused by minute substances attached to the medium flying up and adhering to the nozzle 13 is more noticeable in the case of glossy paper than in the case of plain paper. Therefore, it is also preferable not to execute the third ejection control when the type of the medium is, for example, plain paper, and to execute the third ejection control when the type of the medium is, for example, glossy paper.

[0067] Also, when executing the third ejection control only when the humidity acquired by the temperature and humidity sensor 91 is lower than a predetermined threshold value, the threshold value may be configured to change according to conditions. For example, the threshold value when the temperature acquired by the temperature and humidity sensor 91 is the first temperature is set as the first threshold value, and the threshold value when the temperature is higher than the first temperature is set as the second threshold value. In this case, the first threshold value is set lower than the second threshold value. This is because the amount of moisture contained in the air increases as the temperature rises even at the same relative humidity, so the need for humidification decreases as the temperature gets higher. Then, the control unit 80 uses the threshold value corresponding to the temperature detected by the temperature and humidity sensor 91. Note that the threshold value for temperature may be stored in advance as data in the non-volatile memory 83 (see FIG. 3), or may be calculated by the control unit 80 each time according to a predetermined calculation formula. By reducing the opportunity for humidification as the temperature rises in this way, unnecessary humidification can be suppressed and the ink consumption can be suppressed.

[0068] FIG. 8 is a diagram showing an example of the relationship between the humidity threshold value Hms and the temperature Tm. Note that the line L1 is an example of the threshold value Hms that does not depend on the temperature Tm. Line L2 is an example where the relationship between the threshold value Hms and the temperature Tm is linear. Lines L3 and L4 are also examples where the relationship between the threshold value Hms and the temperature Tm is linear. Note that line L2 is shown as a solid line, line L3 is shown as a dashed-dotted line, and line L4 is shown as a dotted-dashed line. The threshold value Hms for the temperature Tm may adopt any of lines L2, L3, and L4. Note that when adopting line L3, since the change in the threshold value Hms is slow in the low-temperature range, the cases of humidification in the low-temperature range increase, and the humidity on the conveyor belt 53 can be more reliably increased. Also, when adopting line L4, since the change in the threshold value Hms is large in the low-temperature range, the cases of humidification in the low-temperature range decrease, and the ink consumption can be suppressed.

[0069] Also, taking the ink discharge amount in the third discharge control when the humidity is the first humidity as the first ink discharge amount, and the ink discharge amount in the third discharge control when the humidity is the second humidity lower than the first humidity as the second ink discharge amount, the second discharge amount may be made larger than the first discharge amount. And the control unit 80 may be configured to use the ink discharge amount corresponding to the humidity detected by the temperature and humidity sensor 91 in the third discharge control. Thereby, an appropriate ink discharge amount corresponding to the humidity is used. Thus, the humidity on the conveyor belt 53 can be appropriately increased.

[0070] The ink discharge amount may be adjusted with a single color of ink, or may be adjusted by increasing the ink colors used. For example, humidity thresholds H1, H2 (H1 < H2) for adjusting the ink discharge amount are set. And when the detected humidity Hs < humidity threshold H1, only yellow ink is used. Also, when the humidity threshold H1 ≤ detected humidity Hs ≤ humidity threshold H2, in addition to yellow ink, either or both of cyan ink and magenta ink are further used. Also, when the humidity threshold H2 < detected humidity Hs, all of these colors of ink, yellow, magenta, cyan, and black, are used. Thereby, an appropriate ink discharge amount corresponding to the humidity is used, and the humidity on the conveyor belt 53 can be appropriately increased.

[0071] Also, when executing the third ejection control, the control unit 80 can also execute the third ejection control using the ink of the color with the highest water content among the inks of multiple colors. By doing so, the humidity on the conveyance belt 53 can be appropriately increased.

[0072] Also, when the line head 12 is configured to be able to eject inks of multiple colors including yellow from different nozzles 13, the control unit 80 can also execute the third ejection control using the yellow ink among the inks of multiple colors. That is, when the ink becomes mist and floats and adheres to the component parts inside the apparatus, that part is likely to stand out as dirt. By executing the third ejection control using the yellow ink among the inks of multiple colors, even if the ink adheres to the component parts inside the apparatus, it can be made less noticeable as dirt.

[0073] Also, the control unit 80 can also execute the third ejection control using the nozzle 13 with a long non-ejection period among the multiple nozzles 13. Thereby, clogging of the nozzle 13 can be suppressed. Note that the nozzle 13 with a long non-ejection period among the multiple nozzles 13 may be the nozzle 13 with a long non-ejection period among the multiple nozzles 13 that eject a single color, or may be the nozzle 13 of the color with a long non-ejection period among the multiple nozzles 13 that eject different colors.

[0074] The present invention is not limited to the embodiments and modifications described above, and various modifications are possible within the scope of the invention described in the claims, and it goes without saying that those are also included in the scope of the present invention.

Explanation of Reference Numerals

[0075] 1... Inkjet printer, 2... Apparatus main body, 3... First media cassette, 4... Second media cassette, 5... Third media cassette, 6... Fourth media cassette, 8... Discharge tray, 9... Cap unit, 9a... Cap portion, 10A, 10B... Ink storage portion, 11... Waste liquid storage portion, 12... Line head, 13... Nozzle, 19... Pair of feed rollers, 21, 22, 23, 24... Pick rollers, 25, 26, 27, 28... Pair of feed rollers, 29~42... Pair of conveyance rollers, 52... Belt unit, 53... Conveyance belt, 54... First roller, 55... Second roller, 80... Control unit, 81... CPU, 82... Volatile memory, 83... Non-volatile memory, 84... Program, 85... Control parameter, 86... Media detection unit, 87... Feed motor, 88... Conveyance motor, 89... Head movement motor, 91... Temperature and humidity sensor, 95... Operation panel

Claims

1. a support section for supporting a medium; a liquid discharge section having a plurality of nozzles for discharging liquid onto the medium supported by the support section; a conveyance section for conveying the medium between the support section and the liquid discharge section; a control section for controlling the liquid discharge section and the conveyance section; characterized by comprising: the control section, as control for discharging liquid from the liquid discharge section, a first discharge control for performing recording on the medium, a second discharge control which is a control different from the first discharge control and for maintaining the liquid discharge section, a third discharge control which is a control different from the first discharge control and the second discharge control and for atomizing liquid between the liquid discharge section and the support section; is capable of executing; further, when the control section executes the third discharge control, the control section executes the third discharge control before feeding the medium between the support section and the liquid discharge section; a liquid discharge apparatus characterized by the above.

2. In the liquid discharge apparatus according to Claim 1, comprising humidity detection means for detecting the humidity inside the apparatus, the control section executes the third discharge control when the humidity acquired by the humidity detection means is lower than a predetermined threshold value; a liquid discharge apparatus characterized by the above.

3. In the liquid discharge apparatus according to Claim 1, when the control section performs the first discharge control, discharging liquid to achieve a first quality, discharging liquid to achieve a second quality which is higher definition than the first quality; are switchable; further, when the control section achieves the first quality, the control section does not execute the third discharge control, and when the control section achieves the second quality, the control section executes the third discharge control; a liquid discharge apparatus characterized by the above.

4. In the liquid discharge apparatus according to Claim 1, when the control section performs recording on a first medium and a second medium following the first medium, the control section executes the third discharge control in a state where the first medium is located downstream in the conveyance direction between the liquid discharge section and the support section and the second medium is located upstream in the conveyance direction between the liquid discharge section and the support section; a liquid discharge apparatus characterized by the above.

5. In the liquid discharge apparatus according to Claim 1, the control section executes the third discharge control using the time from when the control section receives the recording data until the leading end of the first fed medium reaches between the support section and the liquid discharge section; a liquid discharge apparatus characterized by the above.

6. In the liquid ejection device according to any one of claims 1 to 5, the droplets ejected in the third ejection control are smaller than the droplets ejected in the first ejection control and the droplets ejected in the second ejection control. A liquid ejection device characterized by this.

7. In the liquid ejection device according to claim 1, it is configured such that the distance between the liquid ejection unit and the support unit can be adjusted under the control of the control unit, and the control unit makes the distance when executing the third ejection control larger than the distance when executing the first ejection control. A liquid ejection device characterized by this.

8. In the liquid ejection device according to claim 2, it is provided with temperature detection means for detecting the temperature inside the device, the threshold value when the temperature is the first temperature is set as the first threshold value, and the threshold value when the temperature is higher than the first temperature is set as the second threshold value, and the first threshold value is lower than the second threshold value, and the control unit uses the threshold value corresponding to the temperature detected by the temperature detection means. A liquid ejection device characterized by this.

9. In the liquid ejection device according to claim 1, it is provided with humidity detection means for detecting the humidity inside the device, the liquid ejection amount in the third ejection control when the humidity is the first humidity is set as the first ejection amount, and the liquid ejection amount in the third ejection control when the humidity is the second humidity lower than the first humidity is set as the second ejection amount, and the second ejection amount is more than the first ejection amount, and the control unit uses the liquid ejection amount corresponding to the humidity detected by the humidity detection means in the third ejection control. A liquid ejection device characterized by this.

10. In the liquid ejection device according to claim 1, the liquid ejection unit is configured to be able to eject liquids of a plurality of colors from different nozzles, and the control unit executes the third ejection control using the liquid of the color with the largest water content among the plurality of colored liquids. A liquid ejection device characterized by this.

11. In the liquid ejection device according to claim 1, the liquid ejection unit is configured to be able to eject liquids of a plurality of colors including yellow from different nozzles, and the control unit executes the third ejection control using the yellow liquid among the plurality of colored liquids. A liquid ejection device characterized by this.

12. In the liquid ejection device according to claim 1, the control unit executes the third ejection control using the nozzle among the plurality of nozzles having a long non-ejection period. A liquid ejection device characterized by the following.

13. A support part for supporting a medium, A liquid ejection part having a plurality of nozzles for ejecting liquid onto the medium supported by the support part, A conveyance part for sending the medium between the support part and the liquid ejection part, A liquid ejection method in a liquid ejection device including these, As a process of ejecting liquid from the liquid ejection part, A first ejection process for performing recording on the medium, A second ejection process which is a process different from the first ejection process and for maintaining the liquid ejection part, A third ejection process which is a process different from the first ejection process and the second ejection process and for atomizing liquid between the liquid ejection part and the support part, Is executable, When executing the third ejection process, the third ejection process is executed before sending the medium between the support part and the liquid ejection part. A liquid ejection method characterized by the above.

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