Inkjet recording device

Abstract

To improve a conventional head configuration, so as to enable images to be formed respectively on a forward path and a backward path in a main scanning direction.SOLUTION: An inkjet recording device 1 comprises: an inkjet unit 11 that ejects ink to a recording medium 3 while scanning the medium in a main scanning direction; ejection heads 13 for first process liquid, arranged in parallel with the inkjet unit 11 in the main scanning direction, which scan the medium together with the inkjet unit 11 and ejects first process liquid to the recording medium 3; and ejection heads 14 for second process liquid, arranged in parallel with the inkjet unit 11 in the main scanning direction, which scan the medium together with the inkjet unit 11 and eject second process liquid different from the first process liquid to the recording medium 3. At least either of the ejection heads 13 for first process liquid and the ejection heads 14 for second process liquid are arranged at both sides of the inkjet unit 11 in the main scanning direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an inkjet recording apparatus, and more particularly to an inkjet recording apparatus that forms an image by ejecting ink and a treatment liquid onto a recording medium while scanning an inkjet unit in a main scanning direction. [Background technology]

[0002] A scanning inkjet recording device is equipped with an inkjet head that ejects ink while scanning in the main scanning direction. Conventionally, among inkjet heads that scan in the main scanning direction, there is known an inkjet head that is provided on one side of the main scanning direction with a pretreatment liquid head that ejects a pretreatment liquid, and on the other side with a posttreatment liquid head that ejects a posttreatment liquid (see, for example, Patent Document 1). That is, in this conventional technology, the pretreatment liquid head and the posttreatment liquid head are arranged so that the inkjet head that ejects the ink is sandwiched between them. The pretreatment liquid is a liquid that is ejected onto the recording medium before the ink is ejected. The posttreatment liquid is a liquid that is ejected onto the recording medium after the ink has been ejected. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. WO03 / 043825 Summary of the Invention [Problem to be solved by the invention]

[0004] In a configuration in which a pretreatment liquid head is provided on only one side of an inkjet head and a posttreatment liquid head is provided on only the other side of the inkjet head, as in the above-described conventional technology, it is possible to eject the pretreatment liquid, ink, and posttreatment liquid in an appropriate order when the inkjet head moves in one direction of the main scanning direction (for example, the forward direction). That is, it is possible for the pretreatment liquid head to eject the pretreatment liquid onto a recording medium before ink ejection, the inkjet head to eject ink onto the recording medium onto which the pretreatment liquid has been ejected, and further for the posttreatment liquid head to eject the posttreatment liquid onto the recording medium onto which the ink has been ejected.

[0005] However, with the configuration of the above-mentioned conventional technology, when the inkjet head moves in the direction opposite to the main scanning direction (for example, the return direction), it is not possible to eject the pre-treatment liquid, ink, and post-treatment liquid in the appropriate order. Therefore, with the conventional technology, it is necessary to move the inkjet head back and forth in the main scanning direction to form an image of one line corresponding to the printing width of the inkjet head, which results in a problem of low productivity.

[0006] On the other hand, among the treatment liquids that are ejected onto the recording medium separately from the ink, there are liquids that are preferably ejected onto the recording medium before the ink is ejected, liquids that are preferably ejected onto the recording medium after the ink is ejected, and liquids that can be used either before or after the ink is ejected.

[0007] Therefore, the present invention has been made to solve the above-mentioned conventional problems, and aims to provide an inkjet recording device that can improve productivity by improving the conventional head configuration and making it possible to form images on both the forward and backward passes in the main scanning direction. [Means for solving the problem]

[0008] In order to achieve the above object, the invention according to claim 1 is an inkjet recording apparatus, a plurality of inkjet heads arranged at predetermined intervals in the main scanning direction; While scanning in the main scanning direction From each of the plurality of inkjet headsan ink jet unit that ejects ink onto a recording medium; and a scanning unit that is arranged next to the ink jet unit in the main scanning direction and scans together with the ink jet unit to eject ink onto the recording medium. and a flocculating agent for flocculating the ink. a first treatment liquid ejection head that ejects a first treatment liquid, and a second treatment liquid ejection head that is disposed adjacent to the inkjet unit in the main scanning direction and that scans together with the inkjet unit to eject the first treatment liquid onto the recording medium; , not containing the flocculant a second treatment liquid ejection head that ejects a second treatment liquid, and at least one of the first treatment liquid ejection head and the second treatment liquid ejection head is disposed on both sides of the inkjet unit in the main scanning direction. the second treatment liquid ejection head is disposed adjacent to an end of the plurality of inkjet heads at the same interval as the predetermined interval, and the first treatment liquid ejection head is disposed adjacent to an end of the plurality of inkjet heads or at an interval wider than the predetermined interval from the second treatment liquid ejection head, so that the first treatment liquid is prevented from adhering to the inkjet unit and the second treatment liquid ejection head when the first treatment liquid is ejected. The configuration is characterized by the above.

[0009] The invention according to claim 2 is characterized in that, in the inkjet recording device of claim 1, the first treatment liquid is a treatment liquid that is ejected onto the recording medium before ink is ejected by the inkjet unit, and the ejection heads for the first treatment liquid are arranged on both sides of the inkjet unit in the main scanning direction.

[0010] The invention of claim 3 is an inkjet recording device of claim 2, characterized in that the inkjet unit ejects ink onto the recording medium on each of the forward and return passes in the main scanning direction, and the first treatment liquid ejection heads arranged on both sides of the inkjet unit eject the first treatment liquid onto the recording medium before ink is ejected by the inkjet unit by switching the head that ejects the first treatment liquid between the forward pass and the return pass.

[0011] The invention according to claim 4 is characterized in that in the inkjet recording device according to claim 2 or 3, the second treatment liquid is a treatment liquid that is ejected onto the recording medium before or after ink is ejected by the inkjet unit.

[0012] The invention of claim 5 is characterized in that, in the inkjet recording device of claim 1, the second treatment liquid is a treatment liquid that is ejected onto the recording medium after ink is ejected by the inkjet unit, and the ejection heads for the second treatment liquid are arranged on both sides of the inkjet unit in the main scanning direction.

[0013] The invention of claim 6 is an inkjet recording device of claim 5, characterized in that the inkjet unit ejects ink onto the recording medium on each of the forward and return passes in the main scanning direction, and the second treatment liquid ejection heads arranged on both sides of the inkjet unit eject the second treatment liquid onto the recording medium after ink ejection by the inkjet unit by switching the head that ejects the second treatment liquid between the forward pass and the return pass.

[0014] The invention according to claim 7 is characterized in that in the inkjet recording device according to claim 5 or 6, the first treatment liquid is a treatment liquid that is ejected onto the recording medium before or after ink is ejected by the inkjet unit.

[0015] An invention according to claim 8 is the inkjet recording device of claim 1, characterized in that the first treatment liquid is a treatment liquid that is ejected onto the recording medium before ink is ejected by the inkjet unit, and the second treatment liquid is a treatment liquid that is ejected onto the recording medium after ink is ejected by the inkjet unit, and the ejection head for the first treatment liquid and the ejection head for the second treatment liquid are each arranged on both sides of the inkjet unit in the main scanning direction.

[0016] An invention according to claim 9 is an inkjet recording apparatus according to claim 8, characterized in that the inkjet unit ejects ink onto the recording medium on each of the forward and return passes in the main scanning direction, the first treatment liquid ejection heads arranged on both sides of the inkjet unit eject the first treatment liquid onto the recording medium before ink ejection by the inkjet unit by switching the head that ejects the first treatment liquid between the forward pass and the return pass, and the second treatment liquid ejection heads arranged on both sides of the inkjet unit eject the second treatment liquid onto the recording medium after ink ejection by the inkjet unit by switching the head that ejects the second treatment liquid between the forward pass and the return pass.

[0019] Claim 10 The invention according to the present invention is as follows: 9 In any one of the inkjet recording apparatuses, the second treatment liquid contains a resin dispersant in which a resin is dispersed in a solution.

[0020] Claim 11 The invention according to the present invention is as follows: 10 In any one of the inkjet recording apparatuses described above, the ink contains at least a pigment.

[0021] Claim 12 The invention according to the present invention is as follows: 11 In any one of the inkjet recording devices described above, the inkjet unit is configured such that a plurality of nozzles are provided along a direction perpendicular to the main scanning direction, and the ejection head for the first treatment liquid and the ejection head for the second treatment liquid are configured such that a plurality of nozzles are provided at the same positions as the plurality of nozzles along a direction perpendicular to the main scanning direction.

[0023] Claim 13 The invention according to the present invention is as follows: 12In any one of the inkjet recording apparatuses described above, the inkjet recording apparatus further comprises a first cleaning section that cleans the inkjet unit, and a second cleaning section that cleans the first treatment liquid ejection head.

[0024] Claim 14 The invention according to the present invention is as follows: 13 In any one of the inkjet recording apparatuses, the inkjet recording apparatus further comprises a first purge tub that recovers ink purged from the inkjet unit, and a second purge tub that recovers the first treatment liquid purged from the first treatment liquid ejection head. [Effects of the Invention]

[0025] According to the present invention, the ejection head for the first treatment liquid or the ejection head for the second treatment liquid, which are arranged on both sides of the inkjet unit in the main scanning direction, can eject the first treatment liquid or the second treatment liquid onto the recording medium before or after ink ejection by the inkjet unit while the inkjet unit is moving forward or backward, respectively. Therefore, the inkjet recording device can form images while the inkjet unit is moving forward or backward in the main scanning direction, thereby improving productivity. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of an inkjet recording apparatus. [Figure 2] FIG. 2 is a plan view showing an inkjet unit and a treatment liquid ejection head mounted on a carriage. [Figure 3] 3A and 3B are diagrams showing nozzle configurations in an inkjet head, a first treatment liquid ejection head, and a second treatment liquid ejection head. [Figure 4] 3A to 3C are diagrams illustrating the operation of an inkjet unit and a treatment liquid ejection head in the inkjet recording apparatus. [Figure 5]FIG. 10 is a conceptual diagram showing a state in which the carriage has been moved to a position above the purge tub. [Figure 6] FIG. 10 is a conceptual diagram showing a state in which the carriage has been moved to a position above the cleaning unit. [Figure 7] 10A and 10B are diagrams illustrating an example of a cleaning operation by a cleaning unit. [Figure 8] FIG. 10 is a plan view showing an inkjet unit and a treatment liquid ejection head mounted on a carriage in a second embodiment. [Figure 9] 10A to 10C are diagrams illustrating the operation of an inkjet unit and a treatment liquid ejection head according to a second embodiment. [Figure 10] FIG. 11 is a plan view showing an inkjet unit and a treatment liquid ejection head mounted on a carriage in a third embodiment. [Figure 11] 10A to 10C are diagrams illustrating the operation of an inkjet unit and a treatment liquid ejection head according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. Elements common to the embodiments described below are designated by the same reference numerals, and redundant description thereof will be omitted.

[0028] (First embodiment) First, a first embodiment of the present invention will be described. FIG. 1 is a diagram showing a schematic configuration of an inkjet recording apparatus 1 according to one embodiment of the present invention. The XYZ three-dimensional coordinate system shown in FIG. 1 is a coordinate system in which the XY plane is the horizontal plane and the Z direction is the vertical direction, and is a coordinate system common to coordinate systems shown in other figures. The inkjet recording apparatus 1 is a printing device that forms an image by ejecting ink onto a recording medium 3 that is transported along a predetermined transport direction. As shown in FIG. 1, the inkjet recording apparatus 1 includes a transport unit 2 that transports the recording medium 3, an image forming unit 4, and a control unit 30. For example, the recording medium 3 is made of a web-like fabric. However, the present invention is not limited to this, and the recording medium 3 may be printing paper, film, or the like.

[0029] The transport unit 2 transports a web-like or sheet-like recording medium 3 along a predetermined transport direction (the Y direction in FIG. 1). The transport unit 2 includes a pair of transport rollers 2a and 2b and a platen 2c. The pair of transport rollers 2a and 2b rotate about a rotation axis parallel to the X direction in FIG. 1 by driving a transport motor (not shown). This transports the recording medium 3 stretched between the pair of transport rollers 2a and 2b in the transport direction (the Y direction). The platen 2c is a plate-like member disposed between the pair of transport rollers 2a and 2b so that its upper surface is substantially horizontal. The platen 2c supports the recording medium 3 on its upper surface. Alternatively, the platen 2c may be provided with an air vent so that air can be sucked from the side opposite the recording medium 3, thereby adsorbing the recording medium 3 to the upper surface of the platen 2c. In this case, the recording medium 3 is transported in the predetermined transport direction while adsorbed to the upper surface of the platen 2c. The configuration of the conveying unit 2 is not limited to the above, and may be configured, for example, such that an endless conveying belt is stretched between a pair of conveying rollers 2a and 2b, and the recording medium 3 is conveyed in the conveying direction by the conveying belt which moves in a circular motion in accordance with the rotation of the conveying rollers 2a and 2b.

[0030] The transport unit 2 transports the recording medium 3 intermittently along the transport direction (Y direction). That is, the transport unit 2 transports the recording medium 3 a predetermined amount in the transport direction and then stops the transport operation of the recording medium 3. Then, after an image of a predetermined width is formed on the recording medium 3 by the image forming unit 4, the transport unit 2 transports the recording medium 3 again a predetermined amount along the transport direction and then stops the transport operation of the recording medium 3. In this way, the transport unit 2 repeats the operation of transporting the recording medium 3 a predetermined amount in the transport direction and then stopping the transport.

[0031] The image forming unit 4 is disposed above the recording medium 3 conveyed by the conveying unit 2, so as to cross in a direction (X direction) perpendicular to the conveying direction (Y direction). The image forming unit 4 forms an image on the recording medium 3 by ejecting ink onto the recording medium 3 when the conveying unit 2 is stopped. The image forming unit 4 includes an inkjet unit 11 that ejects ink of four colors, for example, yellow (Y), magenta (M), cyan (C), and black (K), and a carriage 10 that holds the inkjet unit 11. The carriage 10 is attached to a rail member 5 that crosses above the recording medium 3, and is driven by a motor (not shown) to move back and forth along the extension direction (X direction) of the rail member 5. The movement direction (X direction) of the carriage 10 is the main scanning direction in which the inkjet unit 11 scans when forming an image on the recording medium 3. That is, while the transport of the recording medium 3 is stopped, the image forming unit 4 forms an image by causing the inkjet unit 11 to scan in the main scanning direction and ejecting ink from the inkjet unit 11 onto the recording medium 3. At this time, the inkjet unit 11 ejects ink onto the recording medium 3 based on the image data to be printed. Therefore, while moving in the main scanning direction, the inkjet unit 11 ejects ink onto image areas that contain valid image components in the image data to be printed, and does not eject ink onto margin areas that do not contain valid image components.

[0032] The inkjet unit 11 is provided at the center of the carriage 10 in the main scanning direction. The carriage 10 also has treatment liquid ejection heads 12a and 12b on both sides of the inkjet unit 11 in the main scanning direction. That is, in the main scanning direction, the treatment liquid ejection head 12a is arranged on one side of the inkjet unit 11, and the treatment liquid ejection head 12b is arranged on the other side. These treatment liquid ejection heads 12a and 12b are arranged alongside the inkjet unit 11 in the main scanning direction of the carriage 10, and move in the main scanning direction together with the inkjet unit 11. The treatment liquid ejection heads 12a and 12b eject a predetermined treatment liquid onto the recording medium 3 before or after the inkjet unit 11 ejects ink onto the recording medium 3.

[0033] Furthermore, at least one end of a rail member 5 provided in the image forming unit 4 extends further outward than the transport path along which the recording medium 3 is transported. Therefore, the carriage 10 can move further outward than the transport path along which the rail member 5 extends. A purge tub 6 and a drainage tank 8 are provided at the extended end of the rail member 5, and a cleaning unit 20 is provided adjacent to the purge tub 6 and the drainage tank 8. The purge tub 6 and the drainage tank 8 are used to collect ink and treatment liquid purged and discharged from the inkjet unit 11 and the treatment liquid ejection heads 12a and 12b, respectively. The cleaning unit 20 is used to clean the ink ejection surface of the inkjet unit 11 and the nozzles provided on the treatment liquid ejection surfaces of the treatment liquid ejection heads 12a and 12b. The cleaning unit 20 is disposed on a rail member 21 arranged in a direction (Y direction) parallel to the transport direction of the recording medium 3, and is movable along the rail member 21 in the Y direction.

[0034] The control unit 30 controls the operation of each of the above-mentioned components. For example, when forming an image on the recording medium 3, the control unit 30 intermittently transports the recording medium 3 in the transport direction, and while the transport of the recording medium 3 is stopped, moves the carriage 10 forward or backward along the main scanning direction. For example, while the control unit 30 is moving the carriage 10 forward, it drives the inkjet unit 11 to form an image of one line in the main scanning direction on the recording medium 3. At this time, the width of the image of one line formed on the recording medium 3 corresponds to the printing width of the inkjet unit 11 in the transport direction of the recording medium 3. Then, after the image of one line is formed, the control unit 30 again intermittently transports the recording medium 3. The transport amount of the recording medium 3 at this time corresponds to the width of the image of one line formed by the inkjet unit 11. After the recording medium 3 has been transported by the width of the image of one line, the control unit 30 stops the transport of the recording medium 3 and moves the carriage 10 again along the main scanning direction. If the carriage 10 moved forward last time, it will now move backward, in the opposite direction from the previous time. Then, while the control unit 30 is moving the carriage 10 in the backward direction, it drives the inkjet unit 11 to form an image of one line in the main scanning direction on the recording medium 3. By repeating such intermittent operations, the control unit 30 forms an image on the recording medium 3.

[0035] Furthermore, when cleaning the nozzles of the inkjet unit 11, the control unit 30 moves the carriage 10 to a position above the purge tub 6 or to a position above the cleaning unit 20. When the carriage 10 is moved to a position above the purge tub 6, the control unit 30 drives the inkjet unit 11 and the treatment liquid ejection heads 12a and 12b to purge and discharge the ink and treatment liquid from the nozzles. This makes it possible to prevent nozzle clogging. When the carriage 10 is moved to a position above the cleaning unit 20, the control unit 30 drives the cleaning unit 20 to move it along the Y direction. This allows the cleaning unit 20 to clean the nozzles of the inkjet unit 11 and the treatment liquid ejection heads 12a and 12b.

[0036] Next, a detailed description will be given of the inkjet unit 11 and the treatment liquid ejection heads 12a and 12b mounted on the carriage 10. Figure 2 is a plan view showing the inkjet unit 11 and the treatment liquid ejection heads 12a and 12b mounted on the carriage 10.

[0037] As shown in FIG. 2, the inkjet unit 11 includes multiple inkjet heads 11c, 11m, 11y, and 11k that eject ink of each of the four colors Y, M, C, and K. These inkjet heads 11c, 11m, 11y, and 11k are arranged at predetermined intervals along the main scanning direction. Each of the inkjet heads 11c, 11m, 11y, and 11c includes a number of nozzles 15 (see FIG. 3) on its ejection surface that faces the recording medium 3. These nozzles 15 are arranged along the transport direction of the recording medium 3, which is perpendicular to the main scanning direction, and define the printing width when forming an image on the recording medium 3. For example, the ink ejected from each of the inkjet heads 11c, 11m, 11y, and 11k contains at least a pigment.

[0038] The treatment liquid ejection heads 12a and 12b are arranged in the same row as the inkjet heads 11c, 11m, 11y, and 11k in the main scanning direction. That is, the inkjet heads 11c, 11m, 11y, and 11k are sandwiched between the treatment liquid ejection heads 12a and 12b on both sides in the main scanning direction.

[0039] The treatment liquid ejection head 12a includes a first treatment liquid ejection head 13 and a second treatment liquid ejection head 14. The second treatment liquid ejection head 14 is disposed adjacent to the inkjet head 11c at the same interval as the multiple inkjet heads 11c, 11m, 11y, and 11k. The first treatment liquid ejection head 13 in the treatment liquid ejection head 12a is disposed outside the second treatment liquid ejection head 14. The interval between the first treatment liquid ejection head 13 and the second treatment liquid ejection head 14 is larger than the interval between the multiple inkjet heads 11c, 11m, 11y, and 11k.

[0040] The treatment liquid ejection head 12b includes a first treatment liquid ejection head 13. The first treatment liquid ejection head 13 of the treatment liquid ejection head 12b is arranged outside the inkjet head 11k at a distance wider than the distance between the inkjet heads 11c, 11m, 11y, and 11k. For example, the distance between the first treatment liquid ejection head 13 and the inkjet head 11k of the treatment liquid ejection head 12b is the same as the distance between the first treatment liquid ejection head 13 and the second treatment liquid ejection head 14 of the treatment liquid ejection head 12a.

[0041] As described above, the inkjet recording device 1 of this embodiment is equipped with two ejection heads 13 for the first treatment liquid and one ejection head 14 for the second treatment liquid, and the ejection heads 13 for the first treatment liquid are arranged on both sides of the inkjet unit 11 in the main scanning direction.

[0042] The first treatment liquid ejection head 13 ejects the first treatment liquid onto the recording medium 3. The first treatment liquid is a liquid that is preferably ejected onto the recording medium 3 before the ink is ejected onto the recording medium 3, and is used as a pre-treatment liquid. For example, the first treatment liquid contains an aggregating agent that aggregates ink that contains a pigment. The first treatment liquid containing an aggregating agent aggregates the ink ejected onto the recording medium 3, thereby making the color of the ink stand out and suppressing color unevenness.

[0043] When the inkjet unit 11 is moving in the main scanning direction, the two first treatment liquid ejection heads 13, 13 mounted on the carriage 10 selectively switch the head that ejects the first treatment liquid depending on whether the inkjet unit 11 is moving in the forward direction or the backward direction. For example, when the inkjet head unit 11 is moving in the forward direction shown in FIG. 2, the first treatment liquid ejection head 13 provided on the treatment liquid ejection head 12a ejects the first treatment liquid, thereby ejecting the first treatment liquid onto the recording medium 3 before the inkjet heads 11c, 11m, 11y, and 11k eject ink. Also, when the inkjet unit 11 is moving in the backward direction shown in FIG. 2, the first treatment liquid ejection head 13 provided on the treatment liquid ejection head 12b ejects the first treatment liquid, thereby ejecting the first treatment liquid onto the recording medium 3 before the inkjet heads 11c, 11m, 11y, and 11k eject ink.

[0044] The second treatment liquid ejection head 14 ejects the second treatment liquid onto the recording medium 3. The second treatment liquid may be ejected onto the recording medium 3 before the ink is ejected onto the recording medium 3, or may be ejected onto the recording medium 3 after the ink is ejected onto the recording medium 3. In other words, the second treatment liquid is a liquid that can be used as both a pre-treatment liquid and a post-treatment liquid. For example, the second treatment liquid contains a resin dispersant in which a resin is dispersed in a solution. The second treatment liquid containing the resin dispersant, when ejected onto the recording medium 3 and then dried, hardens the surface of the recording medium 3 and can improve its abrasion resistance.

[0045] When the inkjet unit 11 is moving in the main scanning direction, one of the second treatment liquid ejection heads 14 mounted on the carriage 10 switches the timing of ejecting the second treatment liquid depending on whether the inkjet unit 11 is moving in the forward direction or the backward direction. For example, when the inkjet unit 11 is moving in the forward direction shown in FIG. 2, the second treatment liquid ejection head 14 provided in the treatment liquid ejection head 12a ejects the second treatment liquid onto the recording medium 3 before the inkjet heads 11c, 11m, 11y, and 11k eject ink. Also, when the inkjet unit 11 is moving in the backward direction shown in FIG. 2, the second treatment liquid ejection head 14 provided in the treatment liquid ejection head 12a ejects the second treatment liquid onto the recording medium 3 after the inkjet heads 11c, 11m, 11y, and 11k eject ink.

[0046] 3 is a diagram showing the nozzle configurations of the inkjet heads 11c, 11m, 11y, and 11k, the first treatment liquid ejection head 13, and the second treatment liquid ejection head 14. As shown in FIG. 3, the inkjet heads 11c, 11m, 11y, and 11c each include a large number of nozzles 15 arranged along the transport direction (Y direction) of the recording medium 3. The first treatment liquid ejection head 13 also includes a large number of nozzles 16 arranged along the transport direction (Y direction) of the recording medium 3. The second treatment liquid ejection head 14 also includes a large number of nozzles 17 arranged along the transport direction (Y direction) of the recording medium 3. The nozzles 16 and 17 of the first treatment liquid ejection head 13 and the second treatment liquid ejection head 14 are provided at the same positions as the nozzles 15 of the inkjet heads 11c, 11m, 11y, and 11k in the transport direction of the recording medium 3. Therefore, the first treatment liquid ejection head 13 can eject the first treatment liquid to the positions where the inkjet heads 11c, 11m, 11y, and 11k eject ink. Similarly, the second treatment liquid ejection head 14 can eject the second treatment liquid to the positions where the inkjet heads 11c, 11m, 11y, and 11k eject ink.

[0047] Next, Figure 4 is a diagram showing the operation of the inkjet unit 11 and the treatment liquid ejection heads 12a and 12b in the inkjet recording apparatus 1 of this embodiment. First, Figure 4(a) shows the case where the carriage 10 moves in the forward direction of the main scanning direction. While the carriage 10 is moving in the forward direction of the main scanning direction, the control unit 30 drives the first treatment liquid ejection head 13 of the treatment liquid ejection head 12a, the second treatment liquid ejection head 14 of the treatment liquid ejection head 12a, and the inkjet heads 11c, 11m, 11y, and 11k to form an image on the recording medium 3. Specifically, while moving the carriage 10 in the forward direction, the control unit 30 drives the first treatment liquid ejection head 13 of the treatment liquid ejection head 12a to eject the first treatment liquid 13a onto the recording medium 3, then drives the second treatment liquid ejection head 14 of the treatment liquid ejection head 12a to eject the second treatment liquid 14a onto the recording medium 3, and then drives the inkjet heads 11c, 11m, 11y, and 11k to eject the ink 11a onto the recording medium 3. This allows the first treatment liquid 13a and the second treatment liquid 14a to be ejected onto the recording medium 3 before the ink 11a is ejected. The inkjet heads 11c, 11m, 11y, and 11k then eject the inks 11a of the respective colors Y, M, C, and K onto the recording medium 3 onto which the first treatment liquid 13a and the second treatment liquid 14a have been ejected, thereby forming an image.

[0048] When ejecting the first treatment liquid 13a and the second treatment liquid 14a onto the recording medium 3, the control unit 30 drives the first treatment liquid ejection head 13 and the second treatment liquid ejection head 14 based on the image data to be printed. In other words, the control unit 30 controls the ejection of the first treatment liquid 13a and the second treatment liquid 14a only onto image areas containing valid image components in the image data, and prevents the ejection of the first treatment liquid 13a and the second treatment liquid 14a onto marginal areas containing no valid image components in the image data. This prevents the first treatment liquid 13a and the second treatment liquid 14a from being ejected onto marginal areas onto which ink is not ejected, thereby reducing the consumption of the first treatment liquid 13a and the second treatment liquid 14a. Therefore, compared to an operation in which the first treatment liquid 13a and the second treatment liquid 14a are ejected onto marginal areas as well, this has the advantage of reducing running costs.

[0049] Furthermore, the first treatment liquid ejection head 13, which ejects the first treatment liquid 13a when the carriage 10 is moving in the forward direction, is provided at a position that is spaced a predetermined distance or more from the inkjet heads 11c, 11m, 11y, and 11k and the second treatment liquid ejection head 14, which are arranged inside the carriage 10. Specifically, the first treatment liquid ejection head 13 of the treatment liquid ejection head 12a is provided at a position that is spaced a distance from the adjacent second treatment liquid ejection head 14 that is equal to or greater than the arrangement distance of the inkjet heads 11c, 11m, 11y, and 11k. This makes it possible to prevent the first treatment liquid 13a, which splashes when the first treatment liquid is ejected from the first treatment liquid ejection head 13, from adhering to the inkjet heads 11c, 11m, 11y, and 11k or the second treatment liquid ejection head 14. That is, because the first treatment liquid 13a contains a flocculant, if the first treatment liquid 13a adheres to the nozzles 15 of the inkjet heads 11c, 11m, 11y, and 11k or the nozzles 17 of the second treatment liquid ejection head 14, when the first treatment liquid dries, it may clog the nozzles 15 and 17. To prevent this, the first treatment liquid ejection head 13 of the treatment liquid ejection head 12a is provided at a position spaced a predetermined distance or more from the adjacent second treatment liquid ejection head 14.

[0050] 4(b) shows the case where the carriage 10 moves in the backward direction of the main scanning direction. While the control unit 30 is moving the carriage 10 in the backward direction of the main scanning direction, it drives the first treatment liquid ejection head 13 of the treatment liquid ejection head 12b, the inkjet heads 11c, 11m, 11y, and 11k, and the second treatment liquid ejection head 14 of the treatment liquid ejection head 12a to form an image on the recording medium 3. Specifically, while moving the carriage 10 in the backward direction, the control unit 30 first drives the first treatment liquid ejection head 13 of the treatment liquid ejection head 12b to eject the first treatment liquid 13a onto the recording medium 3, then drives the inkjet heads 11c, 11m, 11y, and 11k to eject the ink 11a onto the recording medium 3, and then drives the second treatment liquid ejection head 14 of the treatment liquid ejection head 12a to eject the second treatment liquid 14a onto the recording medium 3. This allows the first treatment liquid 13a to be ejected onto the recording medium 3 before the ink 11a is ejected, and the second treatment liquid 14a to be ejected onto the recording medium 3 after the ink 11a has been ejected. Note that even when the carriage 10 is moving in the return direction, the control unit 30 drives the first treatment liquid ejection head 13 and the second treatment liquid ejection head 14 based on the image data to be printed. This allows control so that the first treatment liquid 13a and the second treatment liquid 14a are not ejected into margin areas in the image data that do not contain valid image components.

[0051] Furthermore, the first treatment liquid ejection head 13, which ejects the first treatment liquid 13a when the carriage 10 is moving in the return direction, is located at a position that is at least a predetermined distance away from the inkjet heads 11c, 11m, 11y, and 11k and the second treatment liquid ejection head 14, which are arranged inside the carriage 10. Specifically, the first treatment liquid ejection head 13 of the treatment liquid ejection head 12b is located at a position that is at least the same distance away from the adjacent inkjet head 11k as the arrangement interval between the inkjet heads 11c, 11m, 11y, and 11k. This prevents the first treatment liquid 13a, which splashes when the first treatment liquid 13a is ejected from the first treatment liquid ejection head 13, from adhering to the inkjet heads 11c, 11m, 11y, and 11k or the second treatment liquid ejection head 14. That is, in order to prevent the nozzles 15, 17 from being clogged with the first treatment liquid 13a, the first treatment liquid ejection head 13 of the treatment liquid ejection head 12b is provided at a position spaced a predetermined distance or more from the adjacent inkjet head 11k.

[0052] As described above, the inkjet recording apparatus 1 of this embodiment uses, as the first treatment liquid 13a, a pre-treatment liquid that is preferably ejected onto the recording medium 3 before the ink is ejected onto the recording medium 3, and uses, as the second treatment liquid 14a, a treatment liquid that can be used either before or after the ink is ejected onto the recording medium 3. The inkjet recording apparatus 1 has two ejection heads 13 for the first treatment liquid mounted on the carriage 10. These two ejection heads 13 for the first treatment liquid are arranged on both sides of the inkjet unit 11 that ejects the ink in the main scanning direction, and the head that ejects the first treatment liquid 13a is selectively switched between when the carriage 10 moves in the forward direction and when the carriage 10 moves in the backward direction. Therefore, the inkjet recording apparatus 1 of this embodiment can eject the first treatment liquid 13a onto the recording medium 3 before the ink 11a is ejected onto the recording medium 3, regardless of whether the carriage 10 moves in the forward direction or the backward direction. This allows the inkjet recording apparatus 1 to form an image on the recording medium 3 during both the forward and backward movements of the carriage 10, thereby improving productivity.

[0053] Next, a cleaning operation of the inkjet unit 11 and the treatment liquid ejection heads 12a and 12b in the inkjet recording apparatus 1 will be described. FIG. 5 is a conceptual diagram showing a state in which the carriage 10 has been moved to a position above the purge tub 6. As shown in FIG. 5, the purge tub 6 includes a first purge tub 6a that collects ink purged from the inkjet unit 11, and second purge tubs 6b and 6c that are provided on both sides of the first purge tub 6a and collect the first treatment liquid purged from each of the two first treatment liquid ejection heads 13. The second treatment liquid purged from the second treatment liquid ejection head 14 is also collected by the first purge tub 6a. The drainage tank 8, provided below the purge tub 6, includes a first drainage tank 8a that collects the ink and second treatment liquid purged into the first purge tub 6a, and second drainage tanks 8b and 8c that collect the first treatment liquid purged into the second purge tubs 6b and 6c. The first purge tub 6a and the first waste liquid tank 8a are connected by a first tube 7a, and the ink and second treatment liquid purged and discharged into the first purge tub 6a are supplied to the first waste liquid tank 8a via the first tube 7a. The second purge tub 6b and the second waste liquid tank 8b are connected by a second tube 7b, and the first treatment liquid purged and discharged into the second purge tub 6b is supplied to the second waste liquid tank 8b via the second tube 7b. The second purge tub 6c and the second waste liquid tank 8c are connected by a second tube 7c, and the first treatment liquid purged and discharged into the second purge tub 6c is supplied to the second waste liquid tank 8c via the second tube 7c.

[0054] In this way, the purge tub 6 is configured to have a portion for recovering the ink and the second treatment liquid and a portion for recovering the first treatment liquid, which are provided separately. This is to prevent the first treatment liquid, which is scattered when the first treatment liquid is purged and discharged from the first treatment liquid ejection head 13, from adhering to the inkjet heads 11c, 11m, 11y, and 11k or the second treatment liquid ejection head 14. That is, in this embodiment, a configuration is adopted in which the first purge tub 6a, which recovers the ink and the second treatment liquid, and the second purge tubs 6b and 6c, which recover the first treatment liquid, are separated. As a result, even if the first processing liquid purged and discharged from the first processing liquid ejection head 13 splashes, it is possible to prevent the first processing liquid from going over the partition between the first purge tub 6a and the second purge tubs 6b and 6c, and it is possible to prevent the first processing liquid from adhering to the nozzles 15 of the inkjet heads 11c, 11m, 11y, and 11k and the nozzles 17 of the second processing liquid ejection head 14.

[0055] Furthermore, by separating the first purge tub 6a from the second purge tubs 6b and 6c, it is possible to prevent clogging of the first tube 7a due to adhesion of coagulated ink, and therefore the ink and second treatment liquid purged and discharged from the inkjet heads 11c, 11m, 11y, and 11k and the second treatment liquid ejection head 14 can be appropriately collected in the first waste liquid tank 8a.

[0056] As described above, the first treatment liquid ejection heads 13, 13 are spaced apart from the second treatment liquid ejection head 14 or the inkjet head 11k by a distance equal to or greater than a predetermined value. In other words, even if the first treatment liquid splashes when the first treatment liquid ejection heads 13, 13 purge and discharge the first treatment liquid, the splashed first treatment liquid is designed not to reach the second treatment liquid ejection head 14 or the inkjet head 11k. Even with this configuration, it is possible to prevent the first treatment liquid from adhering to the nozzles 15 of the inkjet heads 11c, 11m, 11y, 11k and the nozzles 17 of the second treatment liquid ejection head 14.

[0057] 6 and 7 are conceptual diagrams showing the state in which the carriage 10 has been moved to a position above the cleaning unit 20. As shown in FIG. 6, the cleaning unit 20 includes a first cleaning unit 24a located at the center in the main scanning direction and second cleaning units 24b and 24c located on either side of the first cleaning unit 24a. The first cleaning unit 24a and the second cleaning units 24b and 24c are located at positions spaced a predetermined distance apart. The first cleaning unit 24a includes a cleaning roller 23a for cleaning the nozzles 15 of the inkjet heads 11c, 11m, 11y, and 11k and the nozzles 17 of the second treatment liquid ejection head 14. The second cleaning units 24b and 24c include cleaning rollers 23b and 23c for cleaning the nozzles 16 of the first treatment liquid ejection heads 13.

[0058] When cleaning the inkjet heads 11c, 11m, 11y, and 11k, the first treatment liquid discharge heads 13, and the second treatment liquid discharge head 14, the cleaning unit 20 brings the cleaning roller 23a into contact with the lower surfaces of the inkjet heads 11c, 11m, 11y, and 11k and the second treatment liquid discharge head 14, and brings the cleaning rollers 23b and 23c into contact with each of the first treatment liquid discharge heads 13, 13. As shown in FIG. 7 , the cleaning unit 20 cleans the discharge surfaces 110 of the inkjet heads 11c, 11m, 11y, and 11k, the first treatment liquid discharge heads 13, 13, and the second treatment liquid discharge head 14, by moving the cleaning rollers 23a, 23b, and 23c in the Y direction along the rail member 21 while rotating them in a predetermined direction.

[0059] As described above, the cleaning unit 20 of this embodiment is configured such that the cleaning rollers 23b, 23c that clean the first treatment liquid ejection heads 13, 13 and the cleaning roller 23a that cleans the inkjet heads 11c, 11m, 11y, 11k and the second treatment liquid ejection head 14 are separated by a predetermined distance or more. Therefore, the first treatment liquid wiped from the ejection surfaces 110 of the first treatment liquid ejection heads 13, 13 by the cleaning rollers 23b, 23c does not re-adhere to the ejection surfaces 110 of the inkjet heads 11c, 11m, 11y, 11k and the second treatment liquid ejection head 14. This makes it possible to prevent ink from coagulating on the ejection surfaces 110 of the inkjet heads 11c, 11m, 11y, 11k and prevents clogging of the nozzles 15.

[0060] (Second embodiment) Next, a second embodiment of the present invention will be described. The inkjet recording apparatus 1 in this embodiment differs from the first embodiment in the arrangement of the inkjet unit 11 and the treatment liquid ejection heads 12a and 12b mounted on the carriage 10. The differences will be described below.

[0061] FIG. 8 is a plan view showing the inkjet unit 11 and treatment liquid ejection heads 12a and 12b mounted on the carriage 10 in the second embodiment. As shown in FIG. 8, the inkjet unit 11 is disposed at the center of the carriage 10 in the main scanning direction. The treatment liquid ejection heads 12a and 12b are disposed on both sides of the inkjet unit 11 in the main scanning direction. As in the first embodiment, the inkjet unit 11 includes multiple inkjet heads 11c, 11m, 11y, and 11k disposed at predetermined intervals in the main scanning direction, and ejects ink of four colors (Y, M, C, and K) onto the recording medium 3. The treatment liquid ejection heads 12a and 12b are disposed in the same row as the multiple inkjet heads 11c, 11m, 11y, and 11k in the main scanning direction.

[0062] The treatment liquid ejection head 12a provided on one side of the inkjet unit 11 includes a first treatment liquid ejection head 13 and a second treatment liquid ejection head 14. In the treatment liquid ejection head 12a, the second treatment liquid ejection head 14 is disposed adjacent to the inkjet head 11c at the same interval as the multiple inkjet heads 11c, 11m, 11y, and 11k. In addition, the first treatment liquid ejection head 13 in the treatment liquid ejection head 12a is disposed outside the second treatment liquid ejection head 14. The interval between the first treatment liquid ejection head 13 and the second treatment liquid ejection head 14 is arranged to be larger than the interval between the multiple inkjet heads 11c, 11m, 11y, and 11k.

[0063] Furthermore, the treatment liquid ejection head 12b provided on the other side of the inkjet unit 11 includes a second treatment liquid ejection head 14. In the treatment liquid ejection head 12b, the second treatment liquid ejection head 14 is disposed adjacent to the inkjet head 11k at the same intervals as the multiple inkjet heads 11c, 11m, 11y, and 11k.

[0064] As described above, the inkjet recording device 1 of this embodiment is equipped with one ejection head 13 for the first treatment liquid and two ejection heads 14 for the second treatment liquid, and the ejection heads 14 for the second treatment liquid are arranged on both sides of the inkjet unit 11 in the main scanning direction.

[0065] The first treatment liquid ejection head 13 ejects the first treatment liquid onto the recording medium 3. The first treatment liquid in this embodiment may be ejected onto the recording medium 3 before the ink is ejected onto the recording medium 3, or may be ejected onto the recording medium 3 after the ink is ejected onto the recording medium 3. In other words, the first treatment liquid is a liquid that can be used as both a pre-treatment liquid and a post-treatment liquid. For example, the first treatment liquid is a liquid that contains an aggregating agent that aggregates ink that contains a pigment.

[0066] The second treatment liquid ejection head 14 ejects the second treatment liquid onto the recording medium 3. The second treatment liquid in this embodiment is a liquid that is preferably ejected onto the recording medium 3 after the ink has been ejected onto the recording medium 3, and is used as a post-treatment liquid. For example, the second treatment liquid is a liquid that contains a resin dispersant in which a resin is dispersed in a solution.

[0067] When the inkjet unit 11 is moving in the main scanning direction, the two second treatment liquid ejection heads 14, 14 mounted on the carriage 10 selectively switch the head that ejects the second treatment liquid depending on whether the inkjet unit 11 is moving in the forward direction or the backward direction. For example, when the inkjet unit 11 is moving in the forward direction shown in FIG. 8, the second treatment liquid ejection head 14 provided on the treatment liquid ejection head 12b ejects the second treatment liquid. As a result, during the forward movement, the second treatment liquid can be ejected onto the recording medium 3 after the inkjet heads 11c, 11m, 11y, and 11k have ejected ink. Also, for example, when the inkjet head unit 11 is moving in the backward direction shown in FIG. 8, the second treatment liquid ejection head 14 provided on the treatment liquid ejection head 12a ejects the second treatment liquid. As a result, during the backward movement, the second treatment liquid can be ejected onto the recording medium 3 after the inkjet heads 11c, 11m, 11y, and 11k have ejected ink.

[0068] When the inkjet unit 11 is moving in the main scanning direction, one of the first treatment liquid ejection heads 13 mounted on the carriage 10 switches the timing of ejecting the first treatment liquid depending on whether the inkjet unit 11 is moving in the forward direction or the backward direction. For example, when the inkjet unit 11 is moving in the forward direction shown in FIG. 8, the first treatment liquid ejection head 13 provided in the treatment liquid ejection head 12a ejects the first treatment liquid onto the recording medium 3 before the inkjet heads 11c, 11m, 11y, and 11k eject ink. Also, for example, when the inkjet unit 11 is moving in the backward direction shown in FIG. 8, the first treatment liquid ejection head 13 provided in the treatment liquid ejection head 12a ejects the first treatment liquid onto the recording medium 3 after the inkjet heads 11c, 11m, 11y, and 11k eject ink.

[0069] Next, Figure 9 is a diagram showing the operation of the inkjet unit 11 and the treatment liquid ejection heads 12a and 12b in the inkjet recording apparatus 1 of this embodiment. First, Figure 9(a) shows the case where the carriage 10 moves in the forward direction of the main scanning direction. While the carriage 10 is moving in the forward direction of the main scanning direction, the control unit 30 drives the first treatment liquid ejection head 13 of the treatment liquid ejection head 12a, the inkjet heads 11c, 11m, 11y, and 11k, and the second treatment liquid ejection head 14 of the treatment liquid ejection head 12b, to form an image on the recording medium 3. Specifically, while moving the carriage 10 in the forward direction, the control unit 30 drives the first treatment liquid ejection head 13 of the treatment liquid ejection head 12a to eject the first treatment liquid 13a onto the recording medium 3, then drives the inkjet heads 11c, 11m, 11y, and 11k to eject the ink 11a onto the recording medium 3, and then drives the second treatment liquid ejection head 14 of the treatment liquid ejection head 12b to eject the second treatment liquid 14a onto the recording medium 3. This allows the first treatment liquid 13a to be ejected onto the recording medium 3 before the ink 11a is ejected, and the second treatment liquid 14a to be ejected onto the recording medium 3 after the ink 11a has been ejected. Note that, similar to the first embodiment, when ejecting the first treatment liquid 13a and the second treatment liquid 14a onto the recording medium 3, the control unit 30 drives the first treatment liquid ejection head 13 and the second treatment liquid ejection head 14 based on image data to be printed.

[0070] 9B shows the case where the carriage 10 moves in the backward direction of the main scanning direction. While the control unit 30 is moving the carriage 10 in the backward direction of the main scanning direction, it drives the inkjet heads 11c, 11m, 11y, and 11k, the second treatment liquid ejection head 14 of the treatment liquid ejection head 12a, and the first treatment liquid ejection head 13 of the treatment liquid ejection head 12a to form an image on the recording medium 3. Specifically, while moving the carriage 10 in the backward direction, the control unit 30 first drives the inkjet heads 11c, 11m, 11y, and 11k to eject the ink 11a onto the recording medium 3, then drives the second treatment liquid ejection head 14 of the treatment liquid ejection head 12a to eject the second treatment liquid 14a onto the recording medium 3, and then drives the first treatment liquid ejection head 13 of the treatment liquid ejection head 12a to eject the first treatment liquid 13a onto the recording medium 3. This allows the first treatment liquid 13a and the second treatment liquid 14a to be ejected onto the recording medium 3 after the ink 11a has been ejected.

[0071] As described above, the inkjet recording apparatus 1 of this embodiment uses, as the first treatment liquid 13a, a treatment liquid that can be used both before and after the ink is ejected onto the recording medium 3, and uses, as the second treatment liquid 14a, a post-treatment liquid that is preferably ejected onto the recording medium 3 after the ink has been ejected onto the recording medium 3. The inkjet recording apparatus 1 has two ejection heads 14 for the second treatment liquid mounted on the carriage 10. These two ejection heads 14 for the second treatment liquid are arranged on both sides of the inkjet unit 11 that ejects the ink in the main scanning direction, and the head that ejects the second treatment liquid 14a is selectively switched between when the carriage 10 moves in the forward direction and when it moves in the backward direction. Therefore, the inkjet recording apparatus 1 of this embodiment can eject the second treatment liquid 14a onto the recording medium 3 after the ink 11a has been ejected onto the recording medium 3, regardless of whether the carriage 10 moves in the forward direction or the backward direction. This allows the inkjet recording apparatus 1 to form an image on the recording medium 3 during both the forward and backward movements of the carriage 10, thereby improving productivity.

[0072] The inkjet recording apparatus 1 also includes a purge tub 6 and a cleaning unit 20, as described in the first embodiment. In the above configuration, the first treatment liquid ejection head 13 is disposed at an outer position spaced a predetermined distance or more from the inkjet heads 11c, 11m, 11y, and 11k and the second treatment liquid ejection head 14. Therefore, the purge tub 6 can be configured with a first purge tub 6a for collecting ink and the second treatment liquid and a second purge tub 6b for collecting the first treatment liquid, separated at positions spaced a predetermined distance or more from each other, which has the advantage of preventing the first treatment liquid from adhering to other heads. Similarly, the cleaning unit 20 can be configured with a first cleaning unit 24a for cleaning the inkjet heads 11c, 11m, 11y, and 11k and the second treatment liquid ejection heads 14, 14, and a second cleaning unit 24b for cleaning the first treatment liquid ejection head 13, separated at positions spaced a predetermined distance or more from each other, which has the advantage of preventing the first treatment liquid from adhering to other heads.

[0073] In addition, other than the points described above, this embodiment is the same as that described in the first embodiment.

[0074] (Third embodiment) Next, a third embodiment of the present invention will be described. The inkjet recording apparatus 1 in this embodiment differs from the first and second embodiments in the arrangement of the inkjet unit 11 and the treatment liquid ejection heads 12a and 12b mounted on the carriage 10. The differences will be described below.

[0075] FIG. 10 is a plan view showing the inkjet unit 11 and treatment liquid ejection heads 12a and 12b mounted on the carriage 10 in the third embodiment. As shown in FIG. 10, the inkjet unit 11 is disposed at the center of the carriage 10 in the main scanning direction. The treatment liquid ejection heads 12a and 12b are disposed on both sides of the inkjet unit 11 in the main scanning direction. As in the first and second embodiments, the inkjet unit 11 includes multiple inkjet heads 11c, 11m, 11y, and 11k disposed at predetermined intervals in the main scanning direction, and ejects ink of four colors (Y, M, C, and K) onto the recording medium 3. The treatment liquid ejection heads 12a and 12b are disposed in the same row as the multiple inkjet heads 11c, 11m, 11y, and 11k in the main scanning direction.

[0076] The treatment liquid ejection head 12a provided on one side of the inkjet unit 11 includes a first treatment liquid ejection head 13 and a second treatment liquid ejection head 14. In the treatment liquid ejection head 12a, the second treatment liquid ejection head 14 is disposed adjacent to the inkjet head 11c at the same interval as the multiple inkjet heads 11c, 11m, 11y, and 11k. In addition, the first treatment liquid ejection head 13 in the treatment liquid ejection head 12a is disposed outside the second treatment liquid ejection head 14. The interval between the first treatment liquid ejection head 13 and the second treatment liquid ejection head 14 is arranged to be larger than the interval between the multiple inkjet heads 11c, 11m, 11y, and 11k.

[0077] The treatment liquid ejection head 12b provided on the other side of the inkjet unit 11 includes a first treatment liquid ejection head 13 and a second treatment liquid ejection head 14. In the treatment liquid ejection head 12b, the second treatment liquid ejection head 14 is disposed adjacent to the inkjet head 11k at the same interval as the multiple inkjet heads 11c, 11m, 11y, and 11k. In the treatment liquid ejection head 12b, the first treatment liquid ejection head 13 is disposed outside the second treatment liquid ejection head 14. The interval between the first treatment liquid ejection head 13 and the second treatment liquid ejection head 14 is larger than the interval between the multiple inkjet heads 11c, 11m, 11y, and 11k.

[0078] As described above, the inkjet recording device 1 of this embodiment is equipped with two ejection heads 13 for the first treatment liquid and two ejection heads 14 for the second treatment liquid, and the ejection heads 13 for the first treatment liquid and the ejection heads 14 for the second treatment liquid are arranged on both sides of the inkjet unit 11 in the main scanning direction.

[0079] The first treatment liquid ejection head 13 ejects the first treatment liquid onto the recording medium 3. The first treatment liquid in this embodiment is a liquid that is preferably ejected onto the recording medium 3 before the ink is ejected onto the recording medium 3, and is used as a pre-treatment liquid. For example, the first treatment liquid is a liquid that contains an aggregating agent that aggregates ink that contains a pigment.

[0080] The second treatment liquid ejection head 14 ejects the second treatment liquid onto the recording medium 3. The second treatment liquid in this embodiment is a liquid that is preferably ejected onto the recording medium 3 after the ink has been ejected onto the recording medium 3, and is used as a post-treatment liquid. For example, the second treatment liquid is a liquid that contains a resin dispersant in which a resin is dispersed in a solution.

[0081] When the inkjet unit 11 moves in the main scanning direction, the two first treatment liquid ejection heads 13, 13 mounted on the carriage 10 selectively switch which head ejects the first treatment liquid depending on whether the inkjet unit 11 is moving in the forward direction or the backward direction. For example, when the inkjet unit 11 moves in the forward direction shown in FIG. 10, the first treatment liquid ejection head 13 provided on the treatment liquid ejection head 12a ejects the first treatment liquid. This allows the first treatment liquid to be ejected onto the recording medium 3 before the inkjet heads 11c, 11m, 11y, and 11k eject ink during the forward direction. Also, for example, when the inkjet unit 11 moves in the backward direction shown in FIG. 10, the first treatment liquid ejection head 13 provided on the treatment liquid ejection head 12b ejects the first treatment liquid. This allows the first treatment liquid to be ejected onto the recording medium 3 before the inkjet heads 11c, 11m, 11y, and 11k eject ink during the backward direction.

[0082] Furthermore, when the inkjet unit 11 is moving in the main scanning direction, the two second treatment liquid ejection heads 14, 14 mounted on the carriage 10 selectively switch the head that ejects the second treatment liquid depending on whether the inkjet unit 11 is moving in the forward direction or the backward direction. For example, when the inkjet unit 11 is moving in the forward direction shown in FIG. 10, the second treatment liquid ejection head 14 provided on the treatment liquid ejection head 12b ejects the second treatment liquid. As a result, during the forward movement, the second treatment liquid can be ejected onto the recording medium 3 after the inkjet heads 11c, 11m, 11y, and 11k have ejected ink. Also, for example, when the inkjet unit 11 is moving in the backward direction shown in FIG. 10, the second treatment liquid ejection head 14 provided on the treatment liquid ejection head 12a ejects the second treatment liquid. As a result, during the backward movement, the second treatment liquid can be ejected onto the recording medium 3 after the inkjet heads 11c, 11m, 11y, and 11k have ejected ink.

[0083] Next, Figure 11 is a diagram showing the operation of the inkjet unit 11 and the treatment liquid ejection heads 12a and 12b in the inkjet recording apparatus 1 of this embodiment. First, Figure 11(a) shows the case where the carriage 10 moves in the forward direction of the main scanning direction. While the carriage 10 is moving in the forward direction of the main scanning direction, the control unit 30 drives the first treatment liquid ejection head 13 of the treatment liquid ejection head 12a, the inkjet heads 11c, 11m, 11y, and 11k, and the second treatment liquid ejection head 14 of the treatment liquid ejection head 12b, to form an image on the recording medium 3. Specifically, while moving the carriage 10 in the forward direction, the control unit 30 drives the first treatment liquid ejection head 13 of the treatment liquid ejection head 12a to eject the first treatment liquid 13a onto the recording medium 3, then drives the inkjet heads 11c, 11m, 11y, and 11k to eject the ink 11a onto the recording medium 3, and then drives the second treatment liquid ejection head 14 of the treatment liquid ejection head 12b to eject the second treatment liquid 14a onto the recording medium 3. This allows the first treatment liquid 13a to be ejected onto the recording medium 3 before the ink 11a is ejected, and the second treatment liquid 14a to be ejected onto the recording medium 3 after the ink 11a has been ejected. Note that, similar to the first embodiment, when ejecting the first treatment liquid 13a and the second treatment liquid 14a onto the recording medium 3, the control unit 30 drives the first treatment liquid ejection head 13 and the second treatment liquid ejection head 14 based on image data to be printed.

[0084] 11(b) shows the case where the carriage 10 moves in the backward direction of the main scanning direction. While the control unit 30 is moving the carriage 10 in the backward direction of the main scanning direction, it drives the first treatment liquid ejection head 13 of the treatment liquid ejection head 12b, the inkjet heads 11c, 11m, 11y, and 11k, and the second treatment liquid ejection head 14 of the treatment liquid ejection head 12a to form an image on the recording medium 3. Specifically, while moving the carriage 10 in the backward direction, the control unit 30 drives the first treatment liquid ejection head 13 of the treatment liquid ejection head 12b to eject the first treatment liquid 13a onto the recording medium 3, then drives the inkjet heads 11c, 11m, 11y, and 11k to eject the ink 11a onto the recording medium 3, and then drives the second treatment liquid ejection head 14 of the treatment liquid ejection head 12a to eject the second treatment liquid 14a onto the recording medium 3. This allows the first treatment liquid 13a to be ejected onto the recording medium 3 before the ink 11a is ejected, and the second treatment liquid 14a to be ejected onto the recording medium 3 after the ink 11a has been ejected. As described above, when the first treatment liquid 13a and the second treatment liquid 14a are ejected onto the recording medium 3, the control unit 30 drives the first treatment liquid ejection head 13 and the second treatment liquid ejection head 14 based on image data to be printed.

[0085] As described above, the inkjet recording apparatus 1 of this embodiment uses, as the first treatment liquid 13a, a pre-treatment liquid that is preferably ejected onto the recording medium 3 before the ink is ejected onto the recording medium 3, and uses, as the second treatment liquid 14a, a post-treatment liquid that is preferably ejected onto the recording medium 3 after the ink has been ejected onto the recording medium 3. The inkjet recording apparatus 1 has two ejection heads 13 for the first treatment liquid and two ejection heads 14 for the second treatment liquid mounted on the carriage 10. The two ejection heads 13, 13 for the first treatment liquid are arranged on both sides of the inkjet unit 11 that ejects ink in the main scanning direction. The two ejection heads 14, 14 for the second treatment liquid are also arranged on both sides of the inkjet unit 11 that ejects ink in the main scanning direction. When the carriage 10 moves in the forward direction and when it moves in the backward direction, one of the two first treatment liquid ejection heads 13, 13 is selectively switched to eject the first treatment liquid 13a, and one of the two second treatment liquid ejection heads 14, 14 is selectively switched to eject the second treatment liquid 14a. Therefore, when the carriage 10 moves in either the forward direction or the backward direction, the inkjet recording apparatus 1 of this embodiment can eject the first treatment liquid 13a onto the recording medium 3 before the ink 11a is ejected onto the recording medium 3, and can eject the second treatment liquid 14a onto the recording medium 3 after the ink 11a has been ejected onto the recording medium 3. This allows the inkjet recording apparatus 1 to form an image on the recording medium 3 during both the forward and backward movements of the carriage 10, thereby improving productivity.

[0086] Furthermore, the inkjet recording apparatus 1 is equipped with a purge tub 6 and a cleaning unit 20, as described in the first embodiment. In the above configuration, each of the two first treatment liquid ejection heads 13, 13 is disposed at an outer position spaced a predetermined distance or more from each of the two second treatment liquid ejection heads 14, 14. Therefore, the purge tub 6 can be provided with a first purge tub 6a that collects ink and the second treatment liquid and second purge tubs 6b, 6c that collect the first treatment liquid, separated at positions spaced a predetermined distance or more apart, which has the advantage of preventing the first treatment liquid from adhering to other heads. In addition, with regard to the cleaning section 20, the first cleaning section 24a that cleans the inkjet heads 11c, 11m, 11y, 11k and the second processing liquid ejection heads 14, 14, and the second cleaning sections 24b, 24c that clean the first processing liquid ejection heads 13, 13 can be provided at positions separated by a predetermined distance or more, which has the advantage of preventing the first processing liquid from adhering to other heads.

[0087] In addition, other than the points described above, this embodiment is the same as that described in the first embodiment.

[0088] (Variation) Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be applied.

[0089] For example, in the above embodiment, the inkjet recording device 1 is exemplified, in which a plurality of inkjet heads 11c, 11m, 11y, and 11k are mounted on the carriage 10 and which can form a color image on the recording medium 3. However, the inkjet recording device 1 is not necessarily limited to a device capable of forming a color image. For example, the inkjet recording device 1 may be a monochrome-only device.

[0090] Furthermore, in the above embodiment, an example has been shown in which the first treatment liquid ejection head 13, which is provided at a position spaced a predetermined distance or more from the inkjet unit 11, is mounted on the same carriage 10 as the inkjet unit 11. However, the first treatment liquid ejection head 13 may be mounted on a carriage separate from the carriage 10 on which the inkjet unit 11 and the second treatment liquid ejection head 14 are mounted. In that case, the carriage on which the first treatment liquid ejection head 13 is mounted may be configured to move in the main scanning direction in synchronization with the carriage 10 on which the inkjet unit 11 and the second treatment liquid ejection head 14 are mounted.

[0091] In the above embodiment, the ink jet heads 11c, 11m, 11y, and 11k eject ink containing at least a pigment. However, the ink is not limited to ink containing a pigment. For example, the ink may be a dye ink.

[0092] In the above embodiment, an example has been described in which cleaning rollers 23a, 23b, and 23c are provided in the cleaning unit 20, and the ejection surfaces 110 of the heads are cleaned by the cleaning rollers 23a, 23b, and 23c. However, the cleaning means provided in the cleaning unit 20 are not necessarily limited to the cleaning rollers 23a, 23b, and 23c. For example, the cleaning means may be a blade-shaped cleaning means made of rubber or the like, or a web-shaped cleaning means made of nonwoven fabric or the like. [Explanation of symbols]

[0093] 1. Inkjet recording device 2. Conveyor section 3. Recording media 4 Image forming unit 6 Purging Tub 6a First purge trough 6b, 6c Second purge trough 10 Carriage 11 Inkjet unit 11c, 11m, 11y, 11k inkjet head 12a, 12b Treatment liquid ejection head 13 First processing liquid ejection head 14 Second processing liquid ejection head 20 Cleaning Department 24a First Cleaning Section 24b, 24c Second cleaning section

Claims

1. An inkjet unit having a plurality of inkjet heads arranged at predetermined intervals in a main scanning direction, and ejecting ink from each of the plurality of inkjet heads onto a recording medium while scanning in the main scanning direction; a first treatment liquid ejection head that is arranged alongside the inkjet unit in the main scanning direction, scans together with the inkjet unit, and ejects a first treatment liquid onto the recording medium, the first treatment liquid including an aggregating agent that aggregates the ink; a second treatment liquid ejection head that is arranged alongside the inkjet unit in the main scanning direction, scans together with the inkjet unit, and ejects the second treatment liquid that does not contain the aggregating agent onto the recording medium; Equipped with at least one of the first treatment liquid ejection head and the second treatment liquid ejection head is disposed on both sides of the inkjet unit in the main scanning direction, the second treatment liquid ejection head is disposed adjacent to an end of the plurality of inkjet heads at the same interval as the predetermined interval; an inkjet recording device characterized in that the ejection head for the first treatment liquid is arranged adjacent to an end of the plurality of inkjet heads or at a distance from the ejection head for the second treatment liquid that is wider than the specified distance, and the first treatment liquid is prevented from adhering to the inkjet unit and the ejection head for the second treatment liquid when the first treatment liquid is ejected.

2. the first treatment liquid is a treatment liquid that is ejected onto the recording medium before ink is ejected by the inkjet unit, 2. The inkjet recording apparatus according to claim 1, wherein the first treatment liquid ejection heads are arranged on both sides of the inkjet unit in the main scanning direction.

3. the inkjet unit ejects ink onto the recording medium in both a forward pass and a backward pass in the main scanning direction, 3. The inkjet recording apparatus according to claim 2, wherein the first treatment liquid ejection heads arranged on both sides of the inkjet unit eject the first treatment liquid onto the recording medium before ink is ejected by the inkjet unit by switching the head that ejects the first treatment liquid between the forward path and the return path.

4. 4. The inkjet recording apparatus according to claim 2, wherein the second treatment liquid is a treatment liquid that is ejected onto the recording medium before or after ink is ejected by the inkjet unit.

5. the second treatment liquid is a treatment liquid that is ejected onto the recording medium after the ink is ejected by the inkjet unit, 2. The inkjet recording apparatus according to claim 1, wherein the second treatment liquid ejection heads are arranged on both sides of the inkjet unit in the main scanning direction.

6. the inkjet unit ejects ink onto the recording medium in both a forward pass and a backward pass in the main scanning direction, The inkjet recording device according to claim 5, characterized in that the second treatment liquid ejection heads arranged on both sides of the inkjet unit eject the second treatment liquid onto the recording medium after ink is ejected by the inkjet unit by switching the head that ejects the second treatment liquid between the forward path and the return path.

7. 7. The inkjet recording apparatus according to claim 5, wherein the first treatment liquid is a treatment liquid that is ejected onto the recording medium before or after ink is ejected by the inkjet unit.

8. the first treatment liquid is a treatment liquid that is ejected onto the recording medium before ink is ejected by the inkjet unit, the second treatment liquid is a treatment liquid that is ejected onto the recording medium after the ink is ejected by the inkjet unit, 2. The inkjet recording apparatus according to claim 1, wherein the first treatment liquid ejection head and the second treatment liquid ejection head are disposed on both sides of the inkjet unit in the main scanning direction.

9. the inkjet unit ejects ink onto the recording medium in both a forward pass and a backward pass in the main scanning direction, the first treatment liquid ejection heads disposed on both sides of the inkjet unit eject the first treatment liquid onto the recording medium before ink is ejected by the inkjet unit by switching the heads that eject the first treatment liquid between the forward path and the return path; The inkjet recording apparatus according to claim 8, wherein the second treatment liquid ejection heads arranged on both sides of the inkjet unit eject the second treatment liquid onto the recording medium after ink is ejected by the inkjet unit by switching the head that ejects the second treatment liquid between the forward path and the return path.

10. 10. The inkjet recording apparatus according to claim 1, wherein the second treatment liquid contains a resin dispersant in which a resin is dispersed in a solution.

11. 11. The inkjet recording apparatus according to claim 1, wherein the ink contains at least a pigment.

12. the inkjet unit is provided with a plurality of nozzles along a direction perpendicular to the main scanning direction, 12. The inkjet recording apparatus according to claim 1, wherein the first treatment liquid ejection head and the second treatment liquid ejection head have a plurality of nozzles at the same positions as the plurality of nozzles along a direction perpendicular to the main scanning direction.

13. a first cleaning unit that cleans the inkjet unit; a second cleaning unit that cleans the first treatment liquid ejection head; 13. The inkjet recording apparatus according to claim 1, further comprising:

14. a first purge tub for recovering ink purged from the inkjet unit; a second purge tub that collects the first processing liquid purged and discharged from the first processing liquid discharge head; 14. The inkjet recording apparatus according to claim 1, further comprising:

Images