Liquid discharge system, and control method for liquid discharge system

Abstract

To solve the problem that when discharging pre-processing liquid to a sheet as well as colored ink, an amount of water absorption of the sheet increases more than when only the colored ink is discharged to the sheet, making a curl of the sheet salient.SOLUTION: A liquid discharge device includes: a first liquid discharge part discharging pre-processing liquid to be liquid for pre-processing to a medium; a second liquid discharge part discharging recording liquid to be liquid for recording to the medium that is discharged with liquid by the first liquid discharge part; and a control part controlling the first liquid discharge part and the second liquid discharge part. With one surface of the medium as a first surface and the other surface as a second surface, the control part adjusts discharge of the pre-processing liquid so as to suppress water absorption difference based on the recording data between the first surface and the second surface.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection system that ejects liquid onto a medium, and also to a method for controlling the liquid ejection system. [Background technology]

[0002] The inkjet recording device described in Patent Document 1 has a liquid supply unit that supplies liquid to the transported paper. The liquid supplied by the liquid supply unit includes colored ink and a pretreatment liquid that is supplied to the paper before the colored ink is supplied. Therefore, the liquid supply unit has a head unit that ejects colored inks and a head unit that ejects a pretreatment liquid. The pretreatment liquid is white ink. The head unit that ejects the pretreatment liquid is disposed adjacent to the head unit that ejects the colored inks on the upstream side in the paper transport direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2019-188699 Summary of the Invention [Problem to be solved by the invention]

[0004] When the pretreatment liquid is ejected onto the paper in addition to the colored ink, the amount of water absorbed by the paper increases compared to when only the colored ink is ejected onto the paper, and curling of the paper may become more noticeable. [Means for solving the problem]

[0005] In order to solve the above problem, the liquid ejection device of the present invention comprises a first liquid ejection unit that ejects a pretreatment liquid, which is a liquid for pretreatment, onto a medium, a second liquid ejection unit that ejects a recording liquid, which is a liquid for recording, onto the medium onto which the liquid has been ejected by the first liquid ejection unit, and a control unit that controls the first liquid ejection unit and the second liquid ejection unit, wherein one side of the medium is referred to as a first surface and the other side is referred to as a second surface, and the control unit adjusts the ejection of the pretreatment liquid so as to suppress a difference in water absorption between the first surface and the second surface based on recording data.

[0006] The liquid ejection device of the present invention comprises a first liquid ejection unit that ejects a pretreatment liquid, which is a liquid for pretreatment, onto a medium; a second liquid ejection unit that ejects a recording liquid, which is a liquid for recording, onto the medium onto which liquid has been ejected by the first liquid ejection unit; and a control unit that controls the first liquid ejection unit and the second liquid ejection unit, wherein one surface of the medium is a first surface and the other surface is a second surface, and the control unit ejects the pretreatment liquid onto an area of ​​the first surface that corresponds to the ejection area of ​​the recording liquid onto the second surface, and ejects the pretreatment liquid onto an area of ​​the second surface that corresponds to the ejection area of ​​the recording liquid onto the first surface.

[0007] Furthermore, the control method for a liquid ejection system of the present invention is a control method for a liquid ejection device that includes a first liquid ejection unit that ejects a pretreatment liquid, which is a liquid for pretreatment, onto a medium, and a second liquid ejection unit that ejects a recording liquid, which is a liquid for recording, onto the medium onto which the liquid has been ejected by the first liquid ejection unit, and is characterized in that one side of the medium is designated as a first surface and the other side is designated as a second surface, and the ejection of the pretreatment liquid is adjusted so as to suppress the difference in water absorption between the first surface and the second surface based on the recording data.

[0008] Furthermore, the control method for a liquid ejection system of the present invention is a control method for a liquid ejection device that includes a first liquid ejection unit that ejects a pretreatment liquid, which is a liquid for pretreatment, onto a medium, and a second liquid ejection unit that ejects a recording liquid, which is a liquid for recording, onto the medium onto which the liquid has been ejected by the first liquid ejection unit, and is characterized in that one surface of the medium is designated as a first surface and the other surface is designated as a second surface, and the pretreatment liquid is ejected onto an area of ​​the first surface that corresponds to the ejection area of ​​the recording liquid onto the second surface, and the pretreatment liquid is ejected onto an area of ​​the second surface that corresponds to the ejection area of ​​the recording liquid onto the first surface. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 3 is a diagram showing a medium transport path of the liquid ejection unit. [Figure 2] FIG. 3 is a block diagram showing a control system of the liquid ejection unit. [Figure 3] FIG. 2 is a diagram schematically showing a liquid flow path. [Figure 4] FIG. 2 is a diagram showing a medium transport path of the liquid ejection device. [Figure 5] 5A and 5B are diagrams showing examples of a pretreatment liquid ejection region and an ink ejection region; [Figure 6] FIG. 2 is a diagram showing a medium transport path of the liquid ejection device. [Figure 7] FIG. 2 is a diagram showing a medium transport path of the liquid ejection device. [Figure 8] 4A and 4B are diagrams showing examples of pretreatment liquid discharge areas and ink discharge areas on the first and second surfaces of a medium. [Figure 9] 10 is a flowchart showing the flow of processing when recording on both sides of a medium. [Figure 10] 10 is a flowchart showing a flow of determining the ejection adjustment of the pretreatment liquid. [Figure 11] 4A and 4B are diagrams showing examples of pretreatment liquid discharge areas and ink discharge areas on the first and second surfaces of a medium. [Figure 12] 10A and 10B are diagrams showing the relationship between the direction of the grain of a medium and the amount of margins on the top, bottom, left, and right sides. [Figure 13] 10A and 10B are diagrams showing the relationship between the direction of the grain of a medium and the amount of margins on the top, bottom, left, and right sides. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be briefly described below. The liquid ejection device according to the first aspect comprises a first liquid ejection unit that ejects a pretreatment liquid, which is a liquid for pretreatment, onto a medium; a second liquid ejection unit that ejects a recording liquid, which is a liquid for recording, onto the medium onto which the liquid has been ejected by the first liquid ejection unit; and a control unit that controls the first liquid ejection unit and the second liquid ejection unit, wherein one side of the medium is designated as a first surface and the other side is designated as a second surface, and the control unit adjusts the ejection of the pretreatment liquid so as to suppress a difference in water absorption between the first surface and the second surface based on recording data.

[0011] According to this aspect, the control unit adjusts the ejection of the pretreatment liquid so as to suppress the difference in water absorption between the first surface and the second surface based on the recording data, thereby suppressing curling caused by the difference in water absorption. Here, the "absorption" in "difference in water absorption between the first surface and the second surface based on the recording data" refers to the absorption of the first surface or the second surface when the pretreatment liquid and the recording liquid are ejected based on the recording data. Also, the "difference in water absorption between the first surface and the second surface based on the recording data" refers to either or both of the difference between the amount of water absorption of the first surface and the amount of water absorption of the second surface, and the difference between the water absorption range of the first surface and the water absorption range of the second surface.

[0012] A second aspect is an aspect dependent on the first aspect, and is characterized in that the control unit adjusts the ejection of the pretreatment liquid based on information about the medium. For example, if the medium is thick or has high rigidity and is therefore less likely to curl, the discharge adjustment of the pretreatment liquid may not be necessary or may require only minor adjustment. According to this aspect, the control unit adjusts the discharge of the pretreatment liquid based on information about the medium, and therefore it is possible to appropriately suppress curling of the medium while suppressing the discharge amount of the pretreatment liquid.

[0013] A third aspect is an aspect dependent on the first or second aspect, and is characterized in that the water absorption difference is the difference between the amount of recording liquid ejected onto the first surface and the amount of recording liquid ejected onto the second surface.

[0014] When the pretreatment liquid is ejected onto the area onto which the recording liquid is ejected, the water absorption difference can be determined based on the ejection amount of the recording liquid. According to this aspect, the water absorption difference is the difference between the ejection amount of the recording liquid onto the first surface and the ejection amount of the recording liquid onto the second surface, so the water absorption difference can be easily determined.

[0015] A fourth aspect is an aspect dependent on the first aspect, and is characterized in that the water absorption difference is the difference between the total amount of the pretreatment liquid and the recording liquid ejected onto the first surface and the total amount of the pretreatment liquid and the recording liquid ejected onto the second surface.

[0016] According to this aspect, the water absorption difference is the difference between the total amount of the pretreatment liquid and the recording liquid ejected onto the first surface and the total amount of the pretreatment liquid and the recording liquid ejected onto the second surface, so that the water absorption difference can be grasped more accurately, and ultimately the water absorption difference can be suppressed more appropriately. This aspect is not limited to the first aspect, but may be subordinate to the second aspect. Also, this aspect may be subordinate to the third aspect by using the third aspect and this aspect separately.

[0017] A fifth aspect is a dependent aspect of the fourth aspect, characterized in that the control unit adjusts the ejection of the pretreatment liquid so that the total amount of ejection of the pretreatment liquid and the recording liquid onto the first surface is equal to the total amount of ejection of the pretreatment liquid and the recording liquid onto the second surface.

[0018] According to this aspect, the control unit adjusts the ejection of the pretreatment liquid so that the total ejection amount of the pretreatment liquid and the recording liquid onto the first surface is equal to the total ejection amount of the pretreatment liquid and the recording liquid onto the second surface, thereby making it possible to reduce the water absorption difference to 0. Therefore, the water supply difference can be more appropriately suppressed, and ultimately, curling caused by the water absorption difference can be more appropriately suppressed.

[0019] A sixth aspect is an aspect dependent on the fourth or fifth aspect, and is characterized in that the control unit ejects the pretreatment liquid onto an area of ​​the first surface that corresponds to an ejection area of ​​the recording liquid onto the second surface, or ejects the pretreatment liquid onto an area of ​​the second surface that corresponds to an ejection area of ​​the recording liquid onto the first surface.

[0020] For example, if the area on the first surface that corresponds to the area where the recording liquid is ejected onto the second surface has a low water absorption rate, curling is likely to occur. Similarly, if the area on the second surface that corresponds to the area where the recording liquid is ejected onto the first surface has a low water absorption rate, curling is likely to occur. According to this aspect, the control unit ejects the pretreatment liquid onto the area on the first surface that corresponds to the area where the recording liquid is ejected onto the second surface, or ejects the pretreatment liquid onto the area on the second surface that corresponds to the area where the recording liquid is ejected onto the first surface, thereby making it possible to appropriately suppress the difference in water absorption and, consequently, to more appropriately suppress curling caused by the difference in water absorption.

[0021] A seventh aspect is an aspect dependent on the first aspect, and is characterized in that when the control unit increases the ejection amount of the pretreatment liquid in the ejection adjustment of the pretreatment liquid, the control unit ejects the pretreatment liquid into a second area outside a first area, which is the ejection area of ​​the pretreatment liquid corresponding to the ejection area of ​​the recording liquid.

[0022] According to this aspect, the difference in water absorption can be reduced by discharging the pretreatment liquid onto the second region, and the scattering of paper dust can be reduced by discharging the pretreatment liquid onto the second region. The first area does not necessarily have to completely coincide with the ejection area of ​​the recording liquid, but may be an area with a margin provided with respect to the ejection area of ​​the recording area. It should be noted that this aspect is not limited to the first aspect, but may be subordinate to any of the second to sixth aspects.

[0023] The eighth aspect is a dependent aspect of the seventh aspect, and is characterized in that the amount of the pretreatment liquid ejected per unit area in the second region is less than the amount of the pretreatment liquid ejected per unit area in the first region.

[0024] According to this aspect, the amount of the pretreatment liquid ejected per unit area in the second region is less than the amount of the pretreatment liquid ejected per unit area in the first region. This makes it possible to reduce the difference in water absorption while saving the pretreatment liquid, thereby reducing curling caused by the difference in water absorption.

[0025] A liquid ejection device according to a ninth aspect includes a first liquid ejection unit that ejects a pretreatment liquid, which is a liquid for pretreatment, onto a medium; a second liquid ejection unit that ejects a recording liquid, which is a liquid for recording, onto the medium onto which liquid has been ejected by the first liquid ejection unit; and a control unit that controls the first liquid ejection unit and the second liquid ejection unit, wherein one surface of the medium is a first surface and the other surface is a second surface, and the control unit ejects the pretreatment liquid onto an area of ​​the first surface that corresponds to the ejection area of ​​the recording liquid onto the second surface, and ejects the pretreatment liquid onto an area of ​​the second surface that corresponds to the ejection area of ​​the recording liquid onto the first surface.

[0026] According to this aspect, the control unit ejects the pretreatment liquid onto an area of ​​the first surface that corresponds to the ejection area of ​​the recording liquid onto the second surface, and ejects the pretreatment liquid onto an area of ​​the second surface that corresponds to the ejection area of ​​the recording liquid onto the first surface, thereby appropriately suppressing the difference in water absorption between the first surface and the second surface, and ultimately suppressing curling caused by the difference in water absorption.

[0027] The tenth aspect is a dependent aspect of the first aspect, and is characterized in that a first liquid ejection unit having the first liquid ejection portion and a second liquid ejection unit having the second liquid ejection portion are connected. According to this aspect, in a configuration in which the first liquid ejection unit and the second liquid ejection unit are connected, the effects of the first aspect described above can be obtained. It should be noted that this aspect is not limited to the first aspect, but may be subordinate to any of the second to ninth aspects.

[0028] The eleventh aspect is a dependent aspect of the tenth aspect, and is characterized in that the first liquid ejection unit and the second liquid ejection unit each have an attachment portion to which a liquid storage portion containing a liquid is attached, and the attachment portion can alternatively be attached with a recording liquid storage portion containing the recording liquid or a pre-treatment liquid storage portion containing the pre-treatment liquid.

[0029] According to this aspect, the mounting section can be alternatively fitted with either a recording liquid storage section containing the recording liquid or a pretreatment liquid storage section containing the pretreatment liquid, which eliminates the need for a dedicated liquid ejection unit for ejecting the pretreatment liquid, increases the number of ways in which the two liquid ejection units can be used, and improves usability for users.

[0030] A twelfth aspect is an aspect dependent on the eleventh aspect, characterized in that the first liquid ejection unit has a first flow path that is a flow path for liquid from the mounting portion to the first liquid ejection portion, the second liquid ejection unit has a second flow path that is a flow path for liquid from the mounting portion to the second liquid ejection portion, a first cleaning liquid storage portion that contains a cleaning liquid for cleaning the first flow path can be attached to the mounting portion of the first liquid ejection unit, and a second cleaning liquid storage portion that contains a cleaning liquid for cleaning the second flow path can be attached to the mounting portion of the second liquid ejection unit.

[0031] According to this aspect, a first cleaning liquid container containing a cleaning liquid for cleaning the first flow path can be attached to the attachment portion of the first liquid ejection unit, so that the first flow path can be easily cleaned. Similarly, a second cleaning liquid container containing a cleaning liquid for cleaning the second flow path can be attached to the attachment portion of the second liquid ejection unit, so that the second flow path can be easily cleaned.

[0032] A thirteenth aspect is an aspect dependent on the twelfth aspect, and is characterized in that the first liquid discharge unit and the second liquid discharge unit have the same configuration. According to this aspect, the first liquid ejection unit and the second liquid ejection unit have the same configuration, which improves usability for the user compared to when they are separate units. This aspect is not limited to the twelfth aspect, but may be subordinate to the tenth or eleventh aspect.

[0033] The fourteenth aspect is a dependent aspect of the tenth aspect, and is characterized in that it includes an inversion unit that inverts the medium received from the first liquid ejection unit and transports it to the second liquid ejection unit.

[0034] When the first liquid ejection unit and the second liquid ejection unit are provided, the first liquid ejection unit can eject the pretreatment liquid onto the first surface, and the second liquid ejection unit can eject the recording liquid onto the first surface. Also, the first liquid ejection unit can eject the pretreatment liquid onto the second surface, and the second liquid ejection unit can eject the recording liquid onto the second surface. Here, the time from when the first liquid discharging unit discharges the pretreatment liquid onto the first surface until when the second liquid discharging unit discharges the pretreatment liquid onto the first surface is defined as time Tm1. Furthermore, the time from when the first liquid discharging unit discharges the pretreatment liquid onto the second surface until when the second liquid discharging unit discharges the pretreatment liquid onto the second surface is defined as time Tm2. According to this aspect, since the reversing unit is provided which reverses the medium received from the first liquid discharging unit and transports it to the second liquid discharging unit, the difference between the time Tm1 and the time Tm2 can be reduced, thereby reducing the difference in recording quality between the first side and the second side. This aspect is not limited to the above-mentioned tenth aspect, but may be subordinate to any of the above-mentioned eleventh to thirteenth aspects.

[0035] A control method for a liquid ejection device according to a 15th aspect is a control method for a liquid ejection device having a first liquid ejection unit that ejects a pretreatment liquid, which is a liquid for pretreatment, onto a medium, and a second liquid ejection unit that ejects a recording liquid, which is a liquid for recording, onto the medium onto which the liquid has been ejected by the first liquid ejection unit, characterized in that one side of the medium is designated as a first surface and the other side is designated as a second surface, and the ejection of the pretreatment liquid is adjusted so as to suppress the difference in water absorption between the first surface and the second surface based on the recording data.

[0036] According to this aspect, the ejection of the pretreatment liquid is adjusted so as to suppress the difference in water absorption between the first surface and the second surface based on the print data, thereby making it possible to suppress curling caused by the difference in water absorption.

[0037] A control method for a liquid ejection device according to a 16th aspect is a control method for a liquid ejection device equipped with a first liquid ejection unit that ejects a pretreatment liquid, which is a liquid for pretreatment, onto a medium, and a second liquid ejection unit that ejects a recording liquid, which is a liquid for recording, onto the medium onto which liquid has been ejected by the first liquid ejection unit, characterized in that one surface of the medium is designated as a first surface and the other surface is designated as a second surface, and the pretreatment liquid is ejected onto an area of ​​the first surface that corresponds to the ejection area of ​​the recording liquid onto the second surface, and the pretreatment liquid is ejected onto an area of ​​the second surface that corresponds to the ejection area of ​​the recording liquid onto the first surface.

[0038] According to this aspect, the pretreatment liquid is ejected onto an area of ​​the first surface that corresponds to the ejection area of ​​the recording liquid onto the second surface, and the pretreatment liquid is ejected onto an area of ​​the second surface that corresponds to the ejection area of ​​the recording liquid onto the first surface, thereby making it possible to appropriately suppress the difference in water absorption between the first surface and the second surface, and ultimately to suppress curling caused by the difference in water absorption.

[0039] The present invention will be specifically described below. The XYZ coordinate system shown in each figure is a Cartesian coordinate system, with the Y axis direction being the direction that intersects with the medium transport direction, i.e., the medium width direction, and also the device depth direction. In this embodiment, of the side surfaces that form the periphery of the device body 2 of the liquid ejection unit 1, 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 device, and as seen from the operator of the liquid ejection unit 1, the +X direction is the left side and the -X direction is the right side. The -X direction is the direction in which media is fed from each media cassette, which will be described later. The +X direction is the direction in which the media is transported at a position opposite the liquid ejection unit 12. The Z-axis direction is the vertical direction, that is, the height direction of the device, with the +Z direction being the upward direction and the -Z direction being the downward direction.

[0040] In the following, the direction in which the medium is transported may be referred to as "downstream," and the opposite direction may be referred to as "upstream." In each figure, the medium transport path is indicated by a dashed line. In the liquid ejection unit 1, the medium is transported through the medium transport path indicated by the dashed line.

[0041] In this embodiment, the liquid ejection unit 1 is an inkjet printer that performs recording by ejecting ink, which is an example of a liquid, onto a medium such as recording paper. The liquid ejection device described below is a device that includes a plurality of liquid ejection units 1. However, the liquid ejection device may also include a single liquid ejection unit 1, in which case the liquid ejection unit 1 may also be referred to as the liquid ejection device 1. In this specification, the terms "recording" and "printing" may be used, but they both have the same meaning in that an image is formed on a medium by ejecting a liquid onto the medium. Therefore, "recording" may be replaced with "printing" or "image formation," and "printing" may be replaced with "recording" or "image formation."

[0042] The liquid ejection unit 1 is provided with a plurality of media cassettes arranged vertically below the device main body 2, which includes a liquid ejection section 12 (described later), specifically a first media cassette 3, a second media cassette 4, a third media cassette 5, and a fourth media cassette 6. Hereinafter, when there is no need to distinguish between these media cassettes, they will simply be referred to as media cassettes. Each media cassette is provided with a pick roller that sends the stored media in the -X direction. Reference numerals 21, 22, 23, and 24 indicate the pick rollers provided for each media cassette. The structure for the stored media to come into contact with the pick roller may be a structure in which the pick roller moves forward and backward relative to the media, or a structure in which the media is pushed up by a lift plate provided in each media cassette.

[0043] Further, a pair of feed rollers is provided for each medium cassette to feed the medium sent out by the pick roller further downstream. Reference numerals 25, 26, 27, and 28 denote pairs of feed rollers provided for each medium cassette. In the following, unless otherwise specified, a "roller pair" is defined as consisting of a drive roller driven by a power source such as a motor, and a driven roller that rotates in contact with the drive roller.

[0044] The medium fed from the first media cassette 3 receives a feeding force from the transport roller pair 29 and 33 and is sent to the transport roller pair 34. The medium fed from the second media cassette 4 receives a feeding force from the transport roller pair 30, 29, and 33 and is sent to the transport roller pair 34. The medium fed from the third media cassette 5 receives a feeding force from the transport roller pairs 31, 30, 29, and 33 and is sent to the transport roller pair 34. The medium fed from the fourth media cassette 6 receives a feeding force from the transport roller pairs 32, 31, 30, 29, and 33 and is sent to the transport roller pair 34. The symbol T1 indicates the transport path of the medium fed from each media cassette to the transport roller pair 34.

[0045] The medium receiving the feeding force from the transport roller pair 34 is sent between the liquid discharge unit 12 and the transport belt 66, that is, to a liquid discharge position facing the liquid discharge unit 12. The transport roller pair 34 constitutes a transport unit that transports the medium between the liquid discharge unit 12 and the transport belt 66. The liquid ejection unit 12 ejects liquid onto the surface of the medium. In this embodiment, the liquid ejection unit 12 is a line head in which multiple nozzles 13 that eject liquid are arranged across the entire area in the width direction of the medium. However, the liquid ejection unit 12 may also be an ink ejection head that is mounted on a carriage and ejects liquid while moving in the width direction of the medium.

[0046] The liquid ejection unit 12 according to this embodiment employs a piezoelectric element, which is a piezoelectric element whose volume changes when a voltage is applied. By controlling the drive waveform of the piezoelectric element, the movement of the meniscus of the nozzle 13 can be controlled, thereby controlling the size and ejection speed of the ejected droplets. In this embodiment, the plurality of nozzles 13 includes a nozzle capable of ejecting yellow ink, a nozzle capable of ejecting magenta ink, a nozzle capable of ejecting cyan ink, and a plurality of nozzles capable of ejecting black ink. Each color of ink is an example of recording liquid for recording on a medium. As will be described in detail later, the nozzles ejecting each color of ink can also eject cleaning liquid and pretreatment liquid, which is a liquid for pretreatment.

[0047] Next, the conveyor belt 66 is an endless belt that is wound around a drive roller 67 and a driven roller 68, and is rotated when the drive roller 67 is driven by a motor (not shown). The medium is attracted to the belt surface of the conveyor belt 66 and conveyed to a position facing the liquid discharger 12. The drive roller 67, the driven roller 68, and the conveyor belt 66 constitute a belt unit 65. The belt unit 65 has the drive roller 67 as its rotation axis and is provided so as to be rotatable by a power source (not shown). By rotating, the belt unit 65 switches between a state in which the medium can be conveyed as shown in FIG. 1 and a position (not shown) in which the belt unit is retracted from the liquid discharger 12.

[0048] The medium onto which the liquid is ejected by the liquid ejection unit 12 is sent toward either the pair of transport rollers 36 or the pair of transport rollers 40 by the pair of transport rollers 35 located downstream of the transport belt 66. Therefore, a path switching flap (not shown) is provided near the downstream side of the pair of transport rollers 35.

[0049] When the medium is turned over and liquid is not ejected onto the medium again, the medium is sent from the transport roller pair 35 toward the transport roller pair 36. Downstream from the transport roller pair 36, discharge path T4 and discharge path T5 can be selected. Therefore, a path switching flap (not shown) is provided near the downstream side of the transport roller pair 36. When discharge path T4 is selected, the medium passes through discharge path T4 and is discharged onto discharge tray 8. A transport roller pair 38 and a transport roller pair 39 are provided on discharge path T4. When the discharge path T5 is selected, the medium passes through the discharge path T5 and is discharged in the +X direction from the discharge unit K3 of the apparatus main body 2. A transport roller pair 44 is provided on the discharge path T5. When a reversing section 70 (described later) is connected to the liquid discharging unit 1, the medium discharged from the discharge section K3 enters the reversing section 70 from a receiving section K4 of the reversing section 70.

[0050] When the surface of the medium is inverted and liquid is ejected onto the medium again, the medium is sent from conveying roller pair 35 toward conveying roller pair 40 and enters switchback path T2. The rotation direction of conveying roller pair 40 is then switched, the medium switches back, and enters reversal path T3, and is sent to conveying roller pair 34 by conveying roller pairs 41, 42, and 43.

[0051] The liquid ejection unit 1 has receiving units K1 and K2 for receiving media on the side surface in the -X direction. The receiving unit K1 is provided at a height position corresponding to the position between the liquid ejection unit 12 and the belt unit 65 in the device height direction. In this embodiment, the height positions of the receiving unit K1 and the ejection unit K3 are approximately the same. The medium received from the receiving unit K1 is sent to the transport roller pair 34 by the transport roller pair 45. Reference symbol T6 denotes a transport path along which the medium received from the receiving unit K1 is transported. The receiving unit K1 may also serve as a feed port when feeding media placed on a loading unit (not shown) provided on the side surface in the -X direction.

[0052] The receiving section K2 is provided at a position further below the position of the fourth medium cassette 6 in the device height direction. The media received from receiving unit K2 is carried by carry-in path T7 into the first media cassette 3, second media cassette 4, third media cassette 5, and fourth media cassette 6. More specifically, carry-in path T7 is provided with pairs of transport rollers 46, 47, and 48 below fourth media cassette 6, and the media receives a feed force from these transport roller pairs to be transported in the +X direction, and then further upward.

[0053] A transport roller pair 54 is provided in the +X direction relative to the fourth medium cassette 6. A path switching flap (not shown) is provided upstream of the transport roller pair 54, and the medium is transported to either the transport roller pair 54 or the transport roller pair 49. When the medium is transported to the transport roller pair 54, a feeding force in the -X direction is applied to the medium by the transport roller pair 54, and the medium is transported into the fourth medium cassette 6.

[0054] A transport roller pair 53 is provided in the +X direction relative to the third medium cassette 5. A path switching flap (not shown) is provided downstream of the transport roller pair 49, and the medium is transported to either the transport roller pair 53 or the transport roller pair 50. When the medium is transported to the transport roller pair 53, a feeding force in the -X direction is applied to the medium by the transport roller pair 53, and the medium is transported into the third medium cassette 5.

[0055] A transport roller pair 52 is provided in the +X direction relative to the second medium cassette 4. A path switching flap (not shown) is provided downstream of the transport roller pair 50, and the medium is transported to either the transport roller pair 52 or the transport roller pair 51. When the medium is transported to the transport roller pair 52, a feed force in the -X direction is applied to the medium by the transport roller pair 52, and the medium is transported into the second medium cassette 4. The transport roller pair 51 is arranged in the +X direction relative to the first media cassette 3, and when the media is transported to the transport roller pair 51, the transport roller pair 51 applies a feed force to the media in the -X direction, and the media is transported into the first media cassette 3.

[0056] Next, reference numeral 200 denotes an attachment part to which a liquid storage part (described later) is attached, which stores the liquid to be ejected from the liquid ejection part 12. The liquid to be ejected from the liquid ejection part 12 is supplied from the attachment part 200 to the liquid ejection part 12 via tubes 14a, 14b, 14c, and 14d (see FIG. 2).

[0057] Reference numeral 9 denotes a cap unit having a cap 9a that caps the liquid discharge unit 12. The cap unit 9 is provided so as to be displaceable by a power source (not shown) between a separated position (see FIG. 1) where the cap 9a is separated from the liquid discharge unit 12 and a cap position (see FIG. 3) where the cap 9a caps the head surface 12a of the liquid discharge unit 12.

[0058] Next, the reversing unit 70 will be described. In this embodiment, the reversing unit 70 is configured as a separate device from the liquid discharge unit 1, and can be mechanically and electrically connected to the liquid discharge unit 1. It can be controlled by a control unit 80 of the liquid discharge unit 1, which will be described later. However, the reversing unit 70 has an optional configuration, and may not necessarily need to be connected to the liquid discharge unit 1. 1, for convenience of explanation, the reversing unit 70 is arranged in the +X direction relative to the liquid discharge unit 1. However, as will be explained later, since the reversing unit 70 is arranged between two liquid discharge units 1, it can be said that the reversing unit 70 may be located in the -X direction when viewed from a specific liquid discharge unit 1.

[0059] The inverting unit 70 has a receiving unit K4 on its side in the -X direction that receives media. The position of the receiving unit K4 in the device height direction is the same as the position of the discharging unit K3, and the receiving unit K4 can receive media discharged from the discharging unit K3. The media transport path downstream from the receiving unit K4 branches into a skip path U5 and a switchback carry-in path U1. Therefore, a path switching flap (not shown) is provided downstream of the receiving unit K4. The inversion unit 70 also has a discharge unit K6 on its side facing the +X direction, which discharges the medium in the +X direction. In this embodiment, the position of the discharge unit K6 in the device height direction is the same as the position of the receiving unit K4. Therefore, when the skip path U5 is selected, the medium travels from the receiving unit K4 via the skip path U5 in a straight line along the X-axis direction to the discharge unit K6, and is then discharged from the discharge unit K6 in the +X direction.

[0060] When the switchback inlet path U1 is selected, the medium enters the switchback path U2, which extends vertically. The switchback path U2 is equipped with conveying roller pairs 55, 56, and 57. The medium fed into the switchback path U2 receives a force from the conveying roller pairs 55 and 56, and optionally from the conveying roller pair 57, and is conveyed downward. When the rear end of the medium passes the branch point between the switchback inlet path U1 and the switchback discharge path U4, the rotation direction of the conveying roller pairs 55, 56, and 57 is switched, and the medium is conveyed upward. The medium is then discharged from the discharge section K6 in the +X direction via the switchback discharge path U4. Therefore, a path switching flap (not shown) or a path guide structure (not shown) is provided near the top of the conveying roller pair 55. Further below the switchback path U2, a discharge unit K5 is provided. The reversing unit 70 can discharge the medium sent from the switchback carry-in path U1 to the switchback path U2 directly in the +X direction from the discharge unit K5 without switching back.

[0061] The above is the configuration of the liquid discharge unit 1 and the reversing section 70, and the control section 80 will be described below with reference to FIG. The control unit 80 performs various controls in the liquid ejection unit 1 and the liquid ejection device 100 described below. Note that Fig. 2 mainly illustrates the components necessary for the following explanation, and does not illustrate other components. Note that the control unit 80 is not limited to being provided in the liquid ejection unit 1, and may be provided outside the liquid ejection unit 1 or outside the liquid ejection device 100 described below. The control unit 80 controls the feeding mechanism 90, the transport mechanism 91, the liquid discharge unit 12, and the mounting unit 200. The control unit 80 also controls the reversing unit 70 connected to the liquid discharge unit 1.

[0062] The feeding mechanism 90 includes the above-mentioned pick rollers 21, 22, 23, and 24, the pairs of feeding rollers 25, 26, 27, and 28, and a motor (not shown) that drives these rollers. The transport mechanism 91 includes the above-mentioned transport roller pairs 29 to 54, a motor (not shown) that drives these rollers, multiple path switching flaps that switch the destination of the above-mentioned medium, and a drive source (not shown) such as a solenoid that drives these path switching flaps. The motor (not shown) that constitutes the feeding mechanism 90 and the motor (not shown) that constitutes the transport mechanism 91 are, for example, DC motors. Each of the motors is provided with a rotary encoder (not shown), and the control unit 80 can detect the rotation direction, rotation amount, and rotation speed of each of the motors by using this rotary encoder. In other words, the control unit 80 can detect the drive direction, drive amount, and drive speed of each of the rollers described above.

[0063] A liquid storage unit that stores the liquid to be ejected from the liquid ejection unit 12 can be attached to the mounting unit 200. The types of liquid include at least a recording liquid for recording on a medium and a pretreatment liquid for pretreatment of the medium. Ink containing a coloring material is one example of the recording liquid. The types of liquid also include a cleaning liquid that cleans the flow path Fr (see FIG. 3) through which the liquid stored in the liquid storage unit flows before being ejected from the liquid ejection unit 12.

[0064] Hereinafter, in this embodiment, a liquid storage unit that stores ink will be referred to as an "ink cartridge." Furthermore, in this embodiment, a liquid storage unit that stores pretreatment liquid will be referred to as a "pretreatment liquid cartridge." Furthermore, in this embodiment, a liquid storage unit that stores cleaning liquid will be referred to as a "cleaning liquid cartridge." Furthermore, when there is no need to distinguish between the cartridges, they may be simply referred to as "cartridges." Furthermore, the term "liquid storage unit" may be used instead of the term "cartridge." The ink cartridge is an example of a recording liquid storage unit that stores recording liquid. The pretreatment liquid cartridge is an example of a pretreatment liquid storage unit that stores pretreatment liquid that performs pretreatment on a medium. The cleaning liquid cartridge is an example of a cleaning liquid storage unit that stores cleaning liquid that cleans the flow path Fr (see FIG. 3).

[0065] The flow path Fr will now be described with reference to Fig. 3. Fig. 3 is a schematic diagram of a liquid flow path, and the flow path Fr includes a flow path Fr1 which is a section within the mounting part 200, a flow path Fr2 which is a section formed by tubes 14a, 14b, 14c, and 14d which connect the mounting part 200 and the liquid discharge part 12, and a flow path Fr3 which is a section within the liquid discharge part 12 which includes the nozzle 13. Note that hereinafter, when there is no need to distinguish between the tubes 14a, 14b, 14c, and 14d, they will be collectively referred to as tubes 14. With the cleaning liquid cartridge attached to the attachment portion 200, the cleaning liquid can be discharged from the nozzle 13 to clean the flow path Fr.

[0066] The mounting portion 200 according to this embodiment includes a first housing portion 211, a second housing portion 212, a third housing portion 213, and a fourth housing portion 214 that house cartridges. That is, the mounting portion 200 according to this embodiment allows a plurality of cartridges to be attached and detached. A liquid supply needle 15 is provided at the bottom of each storage section. The liquid supply needle 15 is provided on one end side of the tube 14. The cartridge is provided with a liquid supply section 310, and when each cartridge is attached to each cartridge storage section, the liquid supply needle 15 enters the liquid supply section 310, making it possible to supply liquid from the cartridge.

[0067] One end of a tube 19 is connected to the cap 9a that caps the liquid discharge unit 12. The other end of the tube 19 enters the waste liquid storage unit 17, which recovers the liquid discharged into the cap 9a. Reference numeral 18 denotes a pump that generates negative pressure within the cap 9a. When the pump 18 is operated with the cap 9a capping the liquid discharge unit 12, the liquid is sucked from the nozzle 13. The cap 9a is an example of a maintenance unit that performs maintenance on the liquid discharge unit 12.

[0068] As described above, in the liquid discharge unit 1, the flow path Fr can be cleaned, and therefore, by cleaning the flow path Fr, it is possible to prevent different types of liquids from mixing together, and good results can be obtained. In this embodiment, the flow path Fr can be easily cleaned because a cleaning liquid cartridge containing a cleaning liquid for cleaning the flow path Fr can be attached to the mounting part 200. Cleaning the flow path Fr prevents different types of liquid from mixing, resulting in good results.

[0069] Ink cartridges are shown as an example in Figures 2 and 3. Specifically, an ink cartridge 301 containing black ink is installed in the first storage section 211, an ink cartridge 302 containing magenta ink is installed in the second storage section 212, an ink cartridge 303 containing cyan ink is installed in the third storage section 213, and an ink cartridge 304 containing yellow ink is installed in the fourth storage section 214.

[0070] In FIG. 3, reference numeral 321 denotes a pretreatment liquid cartridge, and reference numeral 323 denotes a cleaning liquid cartridge. Instead of the ink cartridges, a pretreatment liquid cartridge 321 and a cleaning liquid cartridge 323 can be attached to each of the storage sections. In the following description, the pretreatment liquid cartridge 321 and the cleaning liquid cartridge 323 may be referred to only by their names without reference numerals.

[0071] The liquid storage section, i.e., the cartridge, is provided with a cartridge IC, which is an example of an information storage section that stores information such as the type of liquid and the remaining amount, as shown in Figure 2. Reference numeral 305 denotes a cartridge IC provided in the black ink cartridge 301, and reference numeral 306 denotes a cartridge IC provided in the magenta ink cartridge 302. Reference numeral 307 denotes a cartridge IC provided in the cyan ink cartridge 303, and reference numeral 308 denotes a cartridge IC provided in the yellow ink cartridge 304. The cartridge IC of each ink cartridge stores information such as that the liquid is ink, the ink color, and the remaining amount. The cartridge IC is also provided in the pretreatment liquid cartridge and the cleaning liquid cartridge. Hereinafter, the cartridge IC provided in each cartridge may be simply referred to as the cartridge IC without being distinguished.

[0072] The mounting portion 200 is provided with contacts that can make electrical contact with the cartridge IC. Reference numeral 201 denotes a contact provided in the first housing portion 211, reference numeral 202 denotes a contact provided in the second housing portion 212, reference numeral 203 denotes a contact provided in the third housing portion 213, and reference numeral 204 denotes a contact provided in the fourth housing portion 214. The control unit 80 can detect information such as the type of liquid and the remaining amount by reading the information in the cartridge IC. Furthermore, when the liquid is consumed, the control unit 80 updates the remaining amount information in the cartridge IC based on the consumed amount. Furthermore, the control unit 80 can detect when a cartridge has been replaced by reading the information in the cartridge IC at a predetermined timing or at predetermined intervals.

[0073] Next, the control unit 80 includes a CPU 81 that executes a computer program, in other words, software, a volatile memory 82, and a nonvolatile memory 83. The CPU 81 performs various calculations required to execute a program 84 stored in the nonvolatile memory 83. The volatile memory 82 is used as a temporary data storage area. The nonvolatile memory 83 stores the program 84 and control parameters 85 required to execute the program 84. The program 84 includes programs that execute various processes described below, and the control parameters 85 include parameters for executing the program 84. The various processes described below are realized when the control unit 80 executes the program 84. The control unit 80 can also accept various operational settings from the user via an operation panel 86 provided in the liquid discharge unit 1. The operation panel 86 includes a touch panel, a power button, other setting buttons, and the like (not shown).

[0074] Next, a liquid ejection device using the liquid ejection unit 1 will be described with reference to FIG. 4 and subsequent figures. First, the pretreatment liquid and the cleaning liquid will be described below. At least an ink cartridge and a pretreatment liquid cartridge can be selectively attached to the attachment portion 200 of the liquid ejection unit 1. Furthermore, a cleaning liquid cartridge may also be attached. Therefore, the ink cartridge, the pretreatment liquid cartridge, and the cleaning liquid cartridge have basically the same shape and size of their housings.

[0075] For example, when an ink cartridge is mounted in the mounting portion 200, the liquid ejection unit 1 can eject ink onto a medium to perform recording. Also, for example, when a pretreatment liquid cartridge is mounted in the mounting portion 200, the liquid ejection unit 1 can eject pretreatment liquid onto a medium. Also, for example, when a cleaning liquid cartridge is mounted in the mounting portion 200, the liquid ejection unit 1 can clean the flow path Fr. In addition, when multiple cartridges can be attached to the attachment section 200, cartridges containing ink and cleaning liquid may be mixed, or cartridges containing pretreatment liquid and cleaning liquid may be mixed, but it is preferable to avoid mixing cartridges containing ink and pretreatment liquid.

[0076] The pretreatment liquid may be any conventionally known liquid that is ejected onto a medium before ink ejection to suppress ink bleeding and improve recording quality, and one example of such a liquid may be one that uses pure water as a solvent and contains a coagulant such as a polyvalent metal salt. Of course, such a pretreatment liquid is merely an example, and the present invention is not limited to this. The aggregating agent reacts with the colorant contained in the ink, and with components such as the pigment dispersion and resin that may be contained in the ink, thereby aggregating the colorant. The aggregating agent also increases the viscosity of the ink composition by reacting with the pigment dispersion and / or resin that may be contained in the ink composition. Therefore, mixing of the pretreatment liquid and the ink in the liquid flow path Fr can lead to ejection defects. Therefore, a cleaning process must be performed when replacing the ink cartridge with a pretreatment liquid cartridge, or when replacing the pretreatment liquid cartridge with an ink cartridge. Of course, even if the pretreatment liquid does not contain an aggregating agent, for example, when white ink is used as the pretreatment liquid, mixing with inks of other colors can prevent the desired treatment results from being obtained. Therefore, a cleaning process must be performed when replacing the ink cartridge with a pretreatment liquid cartridge, or when replacing the pretreatment liquid cartridge with an ink cartridge.

[0077] The cleaning liquid may be any liquid capable of cleaning the nozzle 13 and the flow path Fr, and may be, for example, a liquid containing pure water as the main component and a surfactant, a viscosity modifier, and an antifoaming agent. Of course, this is just an example, and the cleaning liquid is not limited to this.

[0078] Next, a specific example of a liquid ejection device will be described. In the following, the liquid ejection device will be referred to by adding capital letters to the reference numeral 100 to distinguish between embodiments, but when no distinction is made between embodiments, the liquid ejection device may be collectively referred to as the liquid ejection device 100. The liquid ejection device 100A shown in Figure 4 includes a first liquid ejection unit 1A and a second liquid ejection unit 1B. Both the first liquid ejection unit 1A and the second liquid ejection unit 1B are the liquid ejection units 1 described with reference to Figure 1. In Figure 4 and subsequent figures, the number of rollers and symbols shown is reduced compared to Figure 1 to avoid cluttering the drawings. The first liquid ejection unit 1A and the second liquid ejection unit 1B are mechanically coupled by a coupling portion (not shown) and electrically connected by a connector (not shown), which enables the control unit 80 of the first liquid ejection unit 1A and the control unit 80 of the second liquid ejection unit 1B to communicate with each other, allowing the first liquid ejection unit 1A and the second liquid ejection unit 1B to work together to eject liquid onto a medium. Similarly, in other embodiments described below, the plurality of liquid ejection units can communicate with each other via the control units 80, and can eject liquid onto a medium in cooperation with each other. Various recording settings and recording execution operations by the user may be executable by only one of the first liquid discharge unit 1A and the second liquid discharge unit 1B, or may be executable by both.

[0079] In the liquid ejection device 100A, after liquid is ejected from the medium by the first liquid ejection unit 1A, the medium is sent to the second liquid ejection unit 1B, and the liquid is ejected by the second liquid ejection unit 1B. The liquid ejection section 12 included in the first liquid ejection unit 1A can be referred to as the first liquid ejection section 12A, and the liquid ejection section 12 included in the second liquid ejection unit 1B can be referred to as the second liquid ejection section 12B.

[0080] In this embodiment, as an example, a pretreatment liquid cartridge is attached to the attachment portion 200 of the first liquid ejection unit 1A, and an ink cartridge is attached to the attachment portion 200 of the second liquid ejection unit 1B. That is, the first liquid ejection unit 1A ejects pretreatment liquid onto a medium, and the second liquid ejection unit 1B ejects ink onto a medium.

[0081] 4, the thick solid line indicates the medium transport path when performing this type of liquid ejection. The medium indicated by the symbol P is sent out from one of the medium cassettes in the first liquid ejection unit 1A, and after pretreatment liquid is ejected onto its first side, it is turned over and pretreatment liquid is ejected onto its second side. It is then sent to the second liquid ejection unit 1B, where recording is performed on its second side, after which it is turned over and recording is performed on its first side, and it is then ejected onto the ejection tray 8. However, the destination of the medium is not limited to this, and the medium may be discharged from the discharge section K3 via the discharge path T5. In this case, the medium may be discharged to an output tray (not shown) attached to the side surface of the second liquid ejection unit 1B in the +X direction. The output tray (not shown) may be configured to be detachable from the second liquid ejection device. Furthermore, the medium discharged from the discharge section K3 may be delivered to a processing device arranged in the +X direction of the second liquid ejection unit 1B, or to an intermediary conveying device that relays the medium to the processing device. The processing device may perform processes such as stapling, punching, saddle stitching, folding, and drying.

[0082] As described above, the liquid ejection device 100A includes a first liquid ejection unit 1A that ejects liquid onto a medium, and a second liquid ejection unit 1B that is capable of receiving the medium onto which the liquid has been ejected by the first liquid ejection unit 1A and ejects the liquid onto the medium. The first liquid ejection unit 1A and the second liquid ejection unit 1B each include a liquid ejection section 12 that ejects the liquid onto the medium, an attachment section 200 to which a liquid storage section that stores the liquid ejected from the liquid ejection section 12 is attached, and a liquid flow path Fr that runs from the attachment section 200 to the liquid ejection section 12. The attachment section 200 can alternatively be attached with an ink cartridge that stores ink for recording on the medium, or a pretreatment liquid cartridge that stores pretreatment liquid for pretreatment of the medium. This feature is also applicable to the other liquid ejection devices described below.

[0083] According to this liquid ejection device 100A, it is possible to eject ink and pretreatment liquid onto a medium using one liquid ejection unit 1. This eliminates the need for a dedicated liquid ejection unit for ejecting pretreatment liquid, increases the number of ways in which the two liquid ejection units can be used, and improves usability for users. Although the liquid ejection device 100A is connected to two liquid ejection units, it may be connected to three or more liquid ejection units.

[0084] When ejecting the pretreatment liquid onto the medium, the control unit 80 ejects the pretreatment liquid onto the medium based on the recording data when recording on the medium with ink. Specifically, the control unit 80 may eject the pretreatment liquid onto the same area as the recording area where recording is performed on the medium, or onto an area that includes the recording area and is slightly larger than the recording area. Fig. 5 shows an example of a pretreatment liquid ejection area and an ink ejection area, in which the symbol As is the pretreatment liquid ejection area, and the symbol Ap is the ink ejection area in the diagram on the right side of Fig. 5. In this example, the pretreatment liquid is ejected onto an area slightly larger than the ink ejection area Ap, but the pretreatment liquid ejection area As may be the same as the ink ejection area Ap. In this way, particularly when the liquid ejection device is an inkjet printer, the area onto which the treatment liquid is ejected can be freely set, so the amount of treatment liquid used can be reduced compared to a configuration in which the treatment liquid is ejected uniformly over the entire surface of the medium. Such a method for discharging the treatment liquid can also be applied to other liquid discharging systems described below.

[0085] The first liquid discharge unit 1A and the second liquid discharge unit 1B according to this embodiment have the same device configuration, which improves usability for the user compared to when the first liquid discharge unit 1A and the second liquid discharge unit 1B have separate device configurations. However, the first liquid discharge unit 1A and the second liquid discharge unit 1B may be separate devices.

[0086] Furthermore, if the flow path Fr provided in the first liquid ejection unit 1A is referred to as the first flow path FrA and the flow path Fr provided in the second liquid ejection unit 1B is referred to as the second flow path FrB, a first cleaning liquid cartridge containing a cleaning liquid for cleaning the first flow path FrA can be attached to the attachment portion 200 of the first liquid ejection unit 1A. Furthermore, a second cleaning liquid cartridge for cleaning the second flow path FB can be attached to the attachment portion 200 of the second liquid ejection unit 1B. With this configuration, the first flow path FrA and the second flow path FrB can be easily cleaned. The first cleaning liquid cartridge and the second cleaning liquid cartridge may be the same cleaning liquid cartridge.

[0087] Next, a liquid discharger 100B shown in FIG. 6 includes a reversing section 70 between a first liquid discharge unit 1A and a second liquid discharge unit 1B. After liquid is ejected onto the medium in the first liquid ejection unit 1A, the medium is sent to the reversing section 70. The medium is then turned over using the switchback path U2 and sent to the second liquid ejection unit 1B, where the liquid is ejected by the second liquid ejection unit 1B. As an example, the first liquid ejection unit 1A ejects a pretreatment liquid onto a medium, and as an example, the second liquid ejection unit 1B ejects ink onto a medium.

[0088] 6, the thick solid line indicates the medium transport path when performing this type of liquid ejection. The medium indicated by the symbol P is sent out from one of the medium cassettes in the first liquid ejection unit 1A, and after pretreatment liquid is ejected onto its first side, it is inverted, and pretreatment liquid is ejected onto its second side. It is then inverted by the inverting section 70 and sent to the second liquid ejection unit 1B, where recording is performed on its first side, and it is then inverted, and recording is performed on its second side, and it is then ejected onto the ejection tray 8.

[0089] According to this mode of use of the liquid ejection device 100B, unlike the above-described liquid ejection device 100A, the order is pre-processing on the first side of the medium, pre-processing on the second side, recording on the first side, and recording on the second side, so it is possible to prevent a large difference in the time from pre-processing to recording on the first side from occurring between the first side and the second side. In other words, if time Tm1 is the time from ejecting the pre-treatment liquid onto the first side of the medium to ejecting the ink, and time Tm2 is the time from ejecting the pre-treatment liquid onto the second side of the medium to ejecting the ink, it is possible to reduce the difference between time Tm1 and time Tm2. At this time, it is preferable that the first liquid ejection unit 1A and the second liquid ejection unit 1B take the same amount of time to reverse the medium along the switchback path T2 and the reversing path T3. That is, the liquid ejection device 100B as described above can reduce the difference between time Tm1 and time Tm2 while preventing the system from becoming larger in size in the X-axis direction, and can therefore reduce the difference in recording quality between the first and second sides of the medium.

[0090] Next, FIG. 7 shows another application form of the liquid ejection device 100B. In this embodiment, the second liquid ejection unit 1B receives the medium onto which liquid has been ejected by the first liquid ejection unit 1A, and then transports the received medium into each medium storage cassette using the transport path T7. The medium transported into each medium storage cassette is then fed, and liquid is ejected. In Figure 7, the symbol Pm indicates the medium transported into each medium storage cassette. According to this usage mode, the media onto which liquid has been ejected by the first liquid ejection unit 1A can be stored in the respective media storage cassettes of the second liquid ejection unit 1B, ensuring sufficient drying time. Furthermore, by using the respective media storage cassettes, which are components for feeding the media, there is no need to provide a dedicated media storage space, which allows for the device to be made more compact.

[0091] The order in which media are loaded into each media cassette and the order in which they are removed when feeding can be set as appropriate, but it is desirable to set it in a way that allows time for the media to dry. For example, when using multiple media cassettes, it is preferable to not immediately feed the media that has just been loaded into a specific media cassette, but to feed the media that was loaded into another media cassette earlier first. Furthermore, it is not necessary to use all of the plurality of media cassettes, and any one or more of the media cassettes may be used.

[0092] As an example, when loading media, the media are loaded in the following order: first media cassette 3, second media cassette 4, third media cassette 5, and fourth media cassette 6. By then feeding the media in the same order, the media have enough time to dry and the drying time can be made uniform across each media cassette. Note that instead of loading and feeding media from the upper media cassette to the lower media cassette in this order, the media may be loaded and fed from the lower media cassette to the upper media cassette in this order. Alternatively, one media cassette may be loaded with media up to its storage limit, and while the media is being fed from that media cassette until it runs out, another media cassette may be loaded with media up to its storage limit. Alternatively, a configuration may be adopted in which media are loaded from the top of the media cassette and the loaded media are removed from the bottom. Furthermore, it is also possible to combine carrying media into each media cassette with using the skip path U5 of the reversing section 70 to eject liquid from the second liquid ejection unit 1B without carrying media into each media cassette. Furthermore, if the throughput of the first liquid ejection unit 1A is higher than that of the second liquid ejection unit 1B, one medium cassette may be used as a buffer, and other medium cassettes may be used for sequential loading and feeding. If the process overflows, the received media may be evacuated to the buffer medium cassette.

[0093] In this way, the second liquid ejection unit 1B includes a plurality of medium cassettes. If one of the plurality of medium cassettes is a first medium storage section and the other is a second medium storage section, the second liquid ejection unit 1B can execute the steps of: carrying the received first medium into the first medium storage section; carrying the received second medium after the first medium into the second medium storage section; and feeding the first medium to the liquid ejection unit 12, and then feeding the second medium to the liquid ejection unit 12. This allows for sufficient drying time by using two media cassettes and feeding media in order from the first one fed.

[0094] Furthermore, in this embodiment, the second liquid ejection unit 1B transports the received medium into the first medium storage section after feeding the first medium transported into the first medium storage section to the liquid ejection section 12. This prevents the medium transported into the first medium storage section first from being used in the reverse order to the medium transported into the first medium storage section next.

[0095] Next, the adjustment of the discharge of the pretreatment liquid will be described with reference to FIG. 8 and subsequent figures. When a pretreatment liquid is ejected onto a medium before ink is ejected onto it, the amount of water absorbed by the medium increases compared to when only ink is ejected onto the medium. As a result, the difference in water absorption between the first and second sides of the medium increases, which can result in noticeable curling. The difference in water absorption between the first surface S1 and the second surface S2 of the medium P will be described with reference to FIG. 8, the symbols Ap1 and Ap2 indicate ink discharge areas. As an example, the ink discharge area Ap1 is a text printing area, and the ink discharge area Ap2 is an image printing area such as a photograph, and the ink discharge duty of the ink discharge area Ap2 is higher than that of the ink discharge area Ap1. Here, the ink discharge duty is the amount of ink discharged per unit area.

[0096] 8, the symbol As indicates a pretreatment liquid discharge area. The pretreatment liquid discharge area As may coincide with the ink discharge areas Ap1 and Ap2, or may have a margin relative to the ink discharge areas AP1 and Ap2, as described with reference to FIG. The first surface S1 has multiple ink discharge areas Ap2, whereas the second surface S2 has only one ink discharge area Ap1 and no ink discharge areas Ap2. This means that the amount of water absorption of the first surface S1 is greater than the amount of water absorption of the second surface S2, i.e., the difference in water absorption between the first surface S1 and the second surface S2 is large, and the tendency for curling becomes stronger.

[0097] 8 is obtained by flipping the first surface S1 horizontally as indicated by the arrow Rt while maintaining the vertical orientation. On the second surface S2, the symbol Au2 corresponds to the ink ejection area Ap2 on the first surface S1. In other words, the area Au2 is the area where the ink ejection area Ap2 on the first surface S1 is transmitted through to the second surface S2.

[0098] Based on the print data, the pretreatment liquid is ejected onto the pretreatment liquid ejection region As on the second surface S2, which corresponds to the ink ejection region Ap1. However, the region Au2 on the second surface S2 is an area where the difference in water absorption between the first surface S1 and the region Au2 is significant, which can cause curling. Therefore, if the pretreatment liquid is ejected onto the region Au2 on the second surface S2, the difference in water absorption between the first surface S1 and the second surface S2 is reduced, and curling can be suppressed. This additional ejection of pretreatment liquid to suppress the difference in water absorption between the first surface S1 and the second surface S2 is called ejection adjustment of the pretreatment liquid.

[0099] The process performed by the control unit 80 will be described below with reference to Fig. 9. Note that the process in Fig. 9 uses the liquid ejection device 100A described with reference to Fig. 4 as an example. When the control unit 80 receives the print data (step S101), it determines whether to adjust the ejection of the pretreatment liquid (step S102). This ejection adjustment determination will be described later with reference to FIG. As a result of the discharge adjustment determination, if it is determined that discharge adjustment of the pretreatment liquid is necessary (Yes in step S103), the control unit 80 determines the discharge adjustment details (step S104). The discharge adjustment details will also be described separately later. As a result of the discharge adjustment determination, if it is determined that discharge adjustment is not necessary (No in step S103), the process proceeds to step S105.

[0100] The control unit 80 causes the first liquid discharging unit 1A to discharge the pre-treatment liquid onto the first surface S1 (step S105) based on the recording data (if No in step S103) or based on the discharge adjustment content (if Yes in step S103). Next, the control unit 80 inverts the medium in the first liquid discharging unit 1A (step S106). Then, the control unit 80 causes the first liquid discharging unit 1A to discharge the pre-treatment liquid onto the second surface S2 (step S107) based on the recording data (if No in step S103) or based on the discharge adjustment content (if Yes in step S103).

[0101] Next, the control unit 80 transfers the medium from the first liquid discharging unit 1A to the second liquid discharging unit 1B (step S108). Next, the control unit 80 causes the second liquid ejection unit 1B to eject ink onto the second surface S2 based on the recording data (step S109). Next, the control unit 80 causes the second liquid ejection unit 1B to reverse the medium (step S110). Then, the control unit 80 causes the second liquid ejection unit 1B to eject ink onto the second surface S2 based on the recording data (step S111), and then ejects the medium (step S112).

[0102] Next, the discharge adjustment determination will be described with reference to FIG. First, the control unit 80 calculates the ejection amount for the first surface S1 based on the recording data (step S201), and then calculates the ejection amount for the second surface S2 (step S202). Next, the control unit 80 determines whether the discharge amount difference Dt, which is the difference between the discharge amount on the first surface S1 and the discharge amount on the second surface S2, exceeds a predetermined threshold value St (step S203). The threshold value St is stored in the non-volatile memory 83. As a result, if the discharge amount difference Dt exceeds the predetermined threshold value St (Yes in step S203), the control unit 80 determines that discharge adjustment of the pre-treatment liquid is necessary (step S204). On the other hand, if the discharge amount difference Dt is equal to or less than the predetermined threshold value St (No in step S203), the control unit 80 determines that discharge adjustment of the pre-treatment liquid is unnecessary (step S205).

[0103] The difference in discharge amount Dt, which is the difference in water absorption between the first surface S1 and the second surface S2, can be the difference between the ink discharge amount onto the first surface S1 and the ink discharge amount onto the second surface S2. This makes it easy to determine the difference in water absorption. However, the discharge amount difference Dt may be the difference between the discharge amount of the pretreatment liquid for the first surface S1 and the discharge amount of the pretreatment liquid for the second surface S2. The discharge amount difference Dt may be the difference between the total amount of pretreatment liquid and ink discharged onto the first surface S1 and the total amount of pretreatment liquid and ink discharged onto the second surface S2, which allows the water absorption difference to be more accurately determined and, in turn, allows the water absorption difference to be more appropriately suppressed.

[0104] Next, the determination of the discharge adjustment contents (step S104 in FIG. 9) will be described. The determination of the discharge adjustment content is a determination of how much pretreatment liquid to discharge and to which area on which surface. In the example of Fig. 8, the second surface S2 has a smaller amount of water absorption than the first surface S1, so the pretreatment liquid is discharged onto the second surface S2 to suppress the difference in water absorption. As a result, the discharge of pretreatment liquid on the second surface S2 differs from the discharge based on the print data. At this time, the pretreatment liquid can be ejected onto the area Au2 corresponding to the ink ejection area Ap2 on the first surface S1. As a result, on the second surface S2, the pretreatment liquid is ejected onto the area Au2 in addition to the pretreatment liquid ejection area As based on the print data.

[0105] Furthermore, when the pretreatment liquid ejection area As based on the recording data overlaps with the area Au2 corresponding to the ink ejection area Ap2 on the first surface S1, the area in the area Au2 excluding the pretreatment liquid ejection area As becomes the area where the pretreatment liquid is additionally ejected for ejection adjustment.

[0106] In the above embodiment, the pretreatment liquid is not additionally ejected onto the area of ​​the first surface S1 corresponding to the ink ejection area Ap1, but the pretreatment liquid may also be additionally ejected onto the area of ​​the first surface S1 corresponding to the ink ejection area Ap1. Also, a threshold value may be set to determine whether or not to additionally eject the pretreatment liquid, and when the ink ejection duty of the ink ejection area exceeds the threshold value, the pretreatment liquid may be additionally ejected onto the corresponding area on the opposite surface. Furthermore, when additional pretreatment liquid is discharged, the pretreatment liquid may be discharged onto the entire surface of the second surface S2. An example is the area Au3 of the second surface S2 shown in Figure 11. This wets the entire second surface S2, which also contributes to preventing paper dust from scattering.

[0107] The determination of the ejection adjustment of the pretreatment liquid shown in FIG. 10 and the determination of the ejection adjustment contents in step SS104 in FIG. 9 are made based on the entire surface of the medium, but the medium may be divided into several regions, and the ejection adjustment determination of the pretreatment liquid and the ejection adjustment contents may be made for each region.

[0108] 10. In addition to the determination in step S203, it is also possible to determine whether or not ejection adjustment of the pretreatment liquid is necessary and to determine the details of the ejection adjustment based on medium information. For example, if the medium is thick or highly rigid and therefore less likely to curl, ejection adjustment of the pretreatment liquid may not be necessary. Furthermore, even when discharge adjustment is required, if curling is unlikely to occur, the discharge adjustment may be minor. Specifically, when there is a first medium P1 and a second medium P2 that is more rigid than the first medium P1, the discharge duty and discharge area when additionally discharging the pretreatment liquid can be reduced for the second medium P2 compared to the first medium P1. This makes it possible to appropriately suppress curling of the medium while suppressing the discharge amount of the pretreatment liquid.

[0109] Furthermore, the threshold value St used in the determination in step S203 of Fig. 10 may be changed based on information about the medium. For example, if the medium is thick or has high rigidity and is therefore less likely to curl, the threshold value St may be set higher than if the medium is thin or has low rigidity and is more likely to curl.

[0110] As described above, the control unit 80 adjusts the discharge of the pretreatment liquid so as to suppress the difference in water absorption between the first surface S1 and the second surface S2 based on the recording data. The control method for the liquid discharge device 100 realized by the control unit 80 also includes a step of adjusting the discharge of the pretreatment liquid so as to suppress the difference in water absorption between the first surface S1 and the second surface S2 based on the recording data. This makes it possible to suppress curling caused by the difference in water absorption between the first surface S1 and the second surface S2. In a configuration in which ink is ejected by the second liquid ejection unit 1B onto a medium onto which pretreatment liquid has been ejected by the first liquid ejection unit 1A, as in this embodiment, there is a risk that the medium that has been pretreated with the pretreatment liquid will curl and come into contact with the liquid ejection section 12B of the second liquid ejection unit 1B. If the pretreatment liquid ejected onto the medium then adheres to the liquid ejection section 12B of the second liquid ejection unit 1B, problems such as clogging of the nozzles of the liquid ejection section 12B may occur. Therefore, it is preferable to suppress curling as in this embodiment. In the above embodiment, the "difference in water absorption" is defined as the difference between the water absorption amount of the first surface S1 and the water absorption amount of the second surface S2, but it may also be the difference between the water absorption range of the first surface S1 and the water absorption range of the second surface S2, or more specifically, the difference between the water absorption area of ​​the first surface S1 and the water absorption area of ​​the second surface S2.

[0111] Furthermore, the control unit 80 may adjust the ejection of the pretreatment liquid so that the total amount of the pretreatment liquid and the ink ejected onto the first surface S1 is equal to the total amount of the pretreatment liquid and the ink ejected onto the second surface S2. This makes it possible to appropriately suppress the difference in water absorption between the first surface S1 and the second surface S2, and ultimately to more appropriately suppress curling caused by the difference in water absorption.

[0112] In the above embodiment, the control unit 80 ejects the pretreatment liquid onto an area Au2 on the second surface S2, which corresponds to the ink ejection area Ap2 on the first surface S1. The control method for the liquid ejection device 100, which is implemented by the control unit 80, includes the step of ejecting the pretreatment liquid onto an area Au2 on the second surface S2, which corresponds to the ink ejection area Ap2 on the first surface S1. This makes it possible to appropriately suppress the difference in water absorption between the first surface S1 and the second surface S2, and in turn makes it possible to more appropriately suppress curling caused by the difference in water absorption. When additional pretreatment liquid is ejected onto the first surface S1 for ejection adjustment, the pretreatment liquid is ejected onto an area of ​​the first surface S1 that corresponds to the ink ejection area onto the second surface S2.

[0113] The control unit 80 may perform pre-treatment ejection to suppress the difference in water absorption between the first surface S1 and the second surface S2 as normal pre-treatment, without making a determination on ejection adjustment as shown in Fig. 10. That is, the control unit 80 may eject the pre-treatment liquid onto an area Au2 on the second surface S2 that corresponds to the ink ejection area Ap2 on the first surface S1, and eject the pre-treatment liquid onto an area on the first surface S1 that corresponds to the ink ejection area on the second surface S2, without making a determination on ejection adjustment as shown in Fig. 10. This makes it possible to appropriately suppress the difference in water absorption between the first surface S1 and the second surface S2, without considering the ejection amount, and ultimately makes it possible to more appropriately suppress curl caused by the difference in water absorption.

[0114] Furthermore, when increasing the ejection amount of the pretreatment liquid in the ejection adjustment of the pretreatment liquid, the control unit 80 may eject the pretreatment liquid onto a second region that is outside the first region, which is the ejection region of the pretreatment liquid corresponding to the ink ejection region. In Fig. 11, the pretreatment liquid ejection region As on the second surface S2 is an example of the first region, and the region Au3 excluding the pretreatment liquid ejection region As is an example of the second region. By discharging the pretreatment liquid in this manner, the difference in water absorption between the first surface S1 and the second surface S2 can be reduced, and by discharging the pretreatment liquid in the second region, scattering of paper dust can be reduced.

[0115] The amount of pre-treatment liquid ejected per unit area in the second region may be less than the amount of pre-treatment liquid ejected per unit area in the first region, thereby reducing the amount of pre-treatment liquid and suppressing the difference in water absorption, thereby suppressing curling caused by the difference in water absorption.

[0116] As described above, the scattering of paper dust can be suppressed by ejecting the pretreatment liquid to wet the surface of the medium. Therefore, the ejection of the pretreatment liquid for the purpose of suppressing the scattering of paper dust can be performed as a control independent of or in addition to the adjustment of the ejection of the pretreatment liquid. For example, when the ejection amount or ejection area of ​​the pretreatment liquid based on the print data is less than a predetermined threshold, the pretreatment liquid may be additionally ejected in order to suppress the scattering of paper dust. If the pretreatment liquid is ejected onto the entire surface of the medium regardless of the ink ejection area based on the print data, scattering of paper dust can be effectively suppressed. Furthermore, when performing the above-described processing, it is also preferable to set the ejection content of the pretreatment liquid based on the type of medium, specifically, the likelihood of paper dust generation. The likelihood of paper dust generation varies depending on, for example, the type of fiber of the medium and the surface treatment, so if the type of medium is prone to paper dust generation, it is preferable to increase the ejection duty of the pretreatment liquid compared to when paper dust generation is relatively unlikely. Furthermore, for media that are prone to paper dust generation, the ejection of the pretreatment liquid with the aim of suppressing paper dust scattering can be omitted. Furthermore, the likelihood of paper dust generation varies depending on the medium transport speed, so when the medium transport speed is a first speed and a second speed that is faster than the first speed, it is preferable to eject the pretreatment liquid at the second speed in order to suppress the scattering of paper dust.

[0117] Furthermore, when the pretreatment liquid is ejected onto the entire surface of the medium, curling may be effectively suppressed by adjusting the margin amount according to the grain direction of the fibers. 12 shows a case where the grain direction of the medium Pj is along the transport direction when the medium Pj passes under the liquid discharger 12 in the +X direction. Note that the symbol Eu indicates the leading edge, and the symbol Ed indicates the trailing edge. Furthermore, the symbols Eh1 and Eh2 indicate the side edge. In this case where the grain direction of the medium Pj is along the transport direction, when liquid is discharged onto the +Z direction surface of the medium Pj, the medium Pj curls along the Y axis direction due to water absorption, causing the side edge Eh1 and Eh2 to rise toward the liquid discharger 12. In this case, it is preferable to make the margin amount Y1 at the leading and trailing ends of the medium Pj larger than the margin amount X1 at the side ends, so that when compared for cases where the area of ​​the pretreatment liquid discharge region As is the same, the relatively large margins at the leading and trailing ends that do not absorb water provide resistance to curling along the Y-axis direction, thereby suppressing curling along the Y-axis direction.

[0118] 13 shows a case where the grain direction of the medium Pk is along the Y-axis direction, i.e., the width direction intersecting the transport direction, when the medium Pk passes under the liquid discharger 12 in the +X direction. In this case where the grain direction of the medium Pk is along the width direction, when liquid is discharged onto the +Z-direction surface of the medium Pk, the medium Pk curls along the X-axis direction due to water absorption, causing the leading edge Eu and trailing edge Ed to rise toward the liquid discharger 12. In this case, it is preferable to make the margin amount X1 at the side edge of the medium Pk larger than the margin amount Y1 at the leading and trailing edges, so that when compared for cases where the area of ​​the pretreatment liquid discharge area As is the same, the relatively large margin portion at the side edge that has not absorbed water acts as a resistance to curling along the X-axis direction, thereby suppressing curling along the X-axis direction.

[0119] The setting of the pretreatment liquid discharge area As described with reference to FIGS. 12 and 13, specifically the relationship between the grain direction of the fibers and the amount of margins on the top, bottom, left, and right sides, can also be used for determining the discharge adjustment of the pretreatment liquid described with reference to FIG. 10 and for determining the discharge adjustment content of the pretreatment liquid in step S104 of FIG. 9. For example, if it is determined that curling is unlikely to occur based on the relationship between the grain direction of the fibers and the amount of margins on the top, bottom, left, and right sides, it is possible to omit the discharge adjustment of the pretreatment liquid, or to reduce the discharge amount and range when additional discharge of the pretreatment liquid is performed. Furthermore, by setting the margins as shown in Figures 12 and 13 when determining the discharge adjustment content of the pretreatment liquid, it is possible to further suppress curling.

[0120] 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 these modifications are also included in the scope of the present invention. [Explanation of symbols]

[0121] 1...liquid discharge unit, 1A...first liquid discharge unit, 1B...second liquid discharge unit, 2...device main body, 3...first medium cassette, 4...second medium cassette, 5...third medium cassette, 6...fourth medium cassette, 8...output tray, 9...cap unit, 9a...cap, 10...ink storage section, 12...liquid ejection section, 13...nozzle, 14a, 14b, 14c, 14d...tube, 15...liquid supply needle, 17...waste liquid storage section, 18...pump, 19...tube, 21, 22, 23, 24...pick roller, 25, 26, 27, 28...feed roller pair, 29-57...transport roller pair, 65...belt unit, 66...transport belt, 67...drive roller, 68...driven roller, 70...reversing section, 80...control section, 81...CPU, 82...volatile memory, 8 3...non-volatile memory, 84...program, 85...control parameters, 86...operation panel, 90...feed mechanism, 91...transport mechanism, 100, 100A, 100B...liquid ejection device, 200...mounting section, 201, 202, 203, 204...contacts, 211...first storage section, 212...second storage section, 213...third storage section, 214...fourth storage section, 301, 302, 303, 304...ink cartridge, 305, 306, 307, 308...cartridge IC, 310...liquid supply section, 321...pre-treatment liquid cartridge, 323...cleaning liquid cartridge, Fr...flow path, Fr1...flow path in supply section, Fr2...flow path in tube, Fr3...flow path in head, Fr4...flow path in nozzle

Claims

1. a first liquid ejection unit that ejects a pretreatment liquid, which is a liquid for pretreatment, onto a medium; a second liquid ejection unit that ejects a recording liquid onto the medium onto which the liquid has been ejected by the first liquid ejection unit; a control unit that controls the first liquid ejection unit and the second liquid ejection unit; Equipped with one surface of the medium is designated as a first surface and the other surface is designated as a second surface, and the control unit adjusts the ejection of the pretreatment liquid so as to suppress a difference in water absorption between the first surface and the second surface based on recording data. A liquid ejection device characterized by:

2. The liquid ejection device according to claim 1 , the control unit adjusts the discharge of the pretreatment liquid based on information about the medium. A liquid ejection device characterized by:

3. 3. The liquid ejection device according to claim 1, the water absorption difference is a difference between the amount of recording liquid ejected onto the first surface and the amount of recording liquid ejected onto the second surface; A liquid ejection device characterized by:

4. The liquid ejection device according to claim 1 , the water absorption difference is a difference between the total amount of the pretreatment liquid and the recording liquid ejected onto the first surface and the total amount of the pretreatment liquid and the recording liquid ejected onto the second surface; A liquid ejection device characterized by:

5. 5. The liquid ejection device according to claim 4, the control unit adjusts the ejection of the pretreatment liquid so that a total ejection amount of the pretreatment liquid and the recording liquid onto the first surface is equal to a total ejection amount of the pretreatment liquid and the recording liquid onto the second surface. A liquid ejection device characterized by:

6. 6. The liquid ejection device according to claim 4, The control unit ejecting the pretreatment liquid onto an area of ​​the first surface corresponding to an ejection area of ​​the recording liquid onto the second surface; Or, the pretreatment liquid is ejected onto an area of ​​the second surface, the area corresponding to an ejection area of ​​the recording liquid onto the first surface; A liquid ejection device characterized by:

7. The liquid ejection device according to claim 1 , when increasing the ejection amount of the pretreatment liquid in the ejection adjustment of the pretreatment liquid, the control unit ejects the pretreatment liquid to a second region that is out of a first region that is an ejection region of the pretreatment liquid corresponding to an ejection region of the recording liquid. A liquid ejection device characterized by:

8. 8. The liquid ejection device according to claim 7, an ejection amount of the pretreatment liquid per unit area in the second region is smaller than an ejection amount of the pretreatment liquid per unit area in the first region; A liquid ejection device characterized by:

9. a first liquid ejection unit that ejects a pretreatment liquid, which is a liquid for pretreatment, onto a medium; a second liquid ejection unit that ejects a recording liquid onto the medium onto which the liquid has been ejected by the first liquid ejection unit; a control unit that controls the first liquid ejection unit and the second liquid ejection unit; Equipped with One side of the medium is the first side and the other side is the second side, The control unit ejecting the pretreatment liquid onto an area of ​​the first surface corresponding to an ejection area of ​​the recording liquid onto the second surface; the pretreatment liquid is ejected onto an area of ​​the second surface, the area corresponding to an ejection area of ​​the recording liquid onto the first surface; A liquid ejection device characterized by:

10. The liquid ejection device according to claim 1 , a first liquid ejection unit including the first liquid ejection portion; a second liquid ejection unit including the second liquid ejection portion; is connected, A liquid ejection device characterized by:

11. The liquid ejection device according to claim 10, the first liquid ejection unit and the second liquid ejection unit each have a mounting portion to which a liquid storage portion that stores liquid is mounted; a recording liquid storage section that stores the recording liquid and a pretreatment liquid storage section that stores the pretreatment liquid can be selectively installed in the installation section; A liquid ejection device characterized by:

12. The liquid ejection device according to claim 11, the first liquid ejection unit includes a first flow path that is a flow path for liquid from the mounting portion to the first liquid ejection portion, the second liquid ejection unit includes a second flow path that is a flow path for liquid from the mounting portion to the second liquid ejection portion, a first cleaning liquid container that contains a cleaning liquid for cleaning the first flow path can be attached to the attachment portion of the first liquid ejection unit; a second cleaning liquid container containing a cleaning liquid for cleaning the second flow path can be attached to the attachment portion of the second liquid ejection unit; A liquid ejection device characterized by:

13. The liquid ejection device according to claim 12, the first liquid ejection unit and the second liquid ejection unit have the same configuration; A liquid ejection device characterized by:

14. The liquid ejection device according to claim 10, a reversing unit that reverses the medium received from the first liquid ejection unit and transports the medium to the second liquid ejection unit; A liquid ejection device characterized by:

15. a first liquid ejection unit that ejects a pretreatment liquid, which is a liquid for pretreatment, onto a medium; a second liquid ejection unit that ejects a recording liquid onto the medium onto which the liquid has been ejected by the first liquid ejection unit; A method for controlling a liquid ejection device comprising: one surface of the medium is designated as a first surface and the other surface is designated as a second surface, and ejection of the pretreatment liquid is adjusted so as to suppress a difference in water absorption between the first surface and the second surface based on recording data; A method for controlling a liquid ejection device.

16. a first liquid ejection unit that ejects a pretreatment liquid, which is a liquid for pretreatment, onto a medium; a second liquid ejection unit that ejects a recording liquid onto the medium onto which the liquid has been ejected by the first liquid ejection unit; A method for controlling a liquid ejection device comprising: One side of the medium is the first side and the other side is the second side, ejecting the pretreatment liquid onto an area of ​​the first surface corresponding to an ejection area of ​​the recording liquid onto the second surface; the pretreatment liquid is ejected onto an area of ​​the second surface, the area corresponding to an ejection area of ​​the recording liquid onto the first surface; A method for controlling a liquid ejection device.

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