JP2017213714A - Printing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress mist stain by particularly efficiently recovering mist of a reaction liquid in a printing apparatus including ink discharge heads and a reaction liquid discharge head.SOLUTION: A printing apparatus includes ink discharge heads to discharge ink, and a reaction liquid discharge head to discharge a reaction liquid that reacts with the ink. The reaction liquid discharge head is disposed in at least one of an uppermost stream and a downmost stream in a moving direction of a medium in the discharge heads. Mist recovery units, whose housing has an air blowout port and an air suction port formed on a bottom part thereof, are respectively disposed adjacent to each other on an upstream side and a downstream side of the reaction liquid discharge head.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a printing apparatus that performs printing using an ink discharge head that discharges ink and a reaction liquid discharge head that discharges a reaction liquid that reacts with ink.

  In addition to ink droplets for forming an image, mist-like minute ink droplets that do not contribute to image formation are generated from the ejection head in the inkjet printing apparatus. The minute ink droplets float in the air and adhere to various parts in the printing apparatus including the ejection head, resulting in ejection failure of the ejection head, deterioration of the function of the printing apparatus, or degradation of image quality. In addition to ink that forms an image, there is also a printing apparatus that includes an ejection head that ejects a reaction liquid that reacts with ink. In this type of printing apparatus, mist of the reaction solution is generated when the reaction solution is discharged, and may adhere to the discharge port surface of the discharge head. When the reaction liquid adheres to the ink in the vicinity of the discharge port of the discharge head, the fixation of the ink is promoted, and the occurrence of inconvenience due to mist becomes more remarkable.

  Patent Document 1 discloses a configuration in which a suction duct for sucking mist and a blow-out duct for blowing air are arranged adjacent to each other between the respective discharge heads in a printing apparatus in which a plurality of discharge heads are arranged. ing.

US Patent Application Publication No. 2006/0238561

  Since the reaction liquid is applied before the image is formed or after the image is formed, the discharge head that discharges the reaction liquid is disposed in front of or behind the discharge head that discharges the ink. Also in the printing apparatus disclosed in Patent Document 1, the ejection head that ejects the reaction liquid is disposed at the foremost end among the plurality of ejection heads. However, only the suction duct is disposed on the outer side (front side) of the ejection head located at the foremost end. For this reason, a part of the reaction liquid mist sucked by the suction duct may leak through the suction duct to the internal mechanism of the printing apparatus, which may cause the internal mechanism to become dirty or deteriorate in function.

  Moreover, in patent document 1, the suction duct and the blowing duct are arrange | positioned in the several space formed between several discharge heads. For this reason, the size of the apparatus increases, the total air volume required for the blowout duct increases, and a large blower having a high blowing capacity is required.

  One of the objects of the present invention is to efficiently collect mist of a reaction liquid and suppress mist contamination particularly in a printing apparatus including an ink discharge head and a reaction liquid discharge head.

  The present invention is a printing apparatus in which a plurality of ejection heads including an ink ejection head that ejects ink and a reaction liquid ejection head that ejects a reaction liquid that reacts with the ink are arranged along a moving direction of a medium, The reaction liquid discharge head is disposed in at least one of the most upstream and the most downstream in the moving direction among the plurality of discharge heads, and is adjacent to the upstream side and the downstream side of the reaction liquid discharge head, respectively. A mist recovery unit having an air blowing hole and an air suction hole at the bottom is provided.

  According to the present invention, particularly in a printing apparatus including an ink discharge head and a reaction liquid discharge head, it is possible to efficiently collect mist of the reaction liquid and suppress mist contamination.

1 is a diagram illustrating a schematic configuration of a printing apparatus according to an embodiment. It is a figure which shows schematic structure of the discharge head and mist collection | recovery apparatus which are shown in FIG. It is a perspective view which shows the 1st, 2nd, 3rd mist collection | recovery unit in a mist collection | recovery apparatus. It is a longitudinal cross-sectional view of each mist collection | recovery unit shown in FIG. It is the longitudinal cross-sectional view, VA-VA sectional view, and VB-VB sectional view of a 1st mist collection | recovery unit. It is a figure which shows the installation state of a 1st mist collection | recovery unit, and its expansion longitudinal cross-section. It is a figure which shows the installation state of a 2nd mist collection | recovery unit, and its expansion longitudinal cross-section. It is a figure which shows the installation state of a 3rd mist collection | recovery unit, and its expansion longitudinal cross-section. It is a figure which shows the positional relationship of a 1st mist collection | recovery unit and a transcription | transfer body, and the enlarged longitudinal cross-section. It is a figure which shows the positional relationship of a 1st mist collection | recovery unit, a transfer body, and a reaction liquid discharge head, and the enlarged longitudinal cross-section. FIG. 3 is a plan view of a reaction liquid discharge head and a mist collection unit as viewed from a transfer body side. It is a longitudinal cross-sectional view which shows the structure of the mist collection | recovery unit in 2nd Embodiment. It is a longitudinal cross-sectional view which shows the structure of the mist collection | recovery unit in 3rd Embodiment. It is a longitudinal cross-sectional view which shows the structure of the mist collection | recovery unit in 4th Embodiment. It is a longitudinal cross-sectional view which shows the structure of the mist collection | recovery unit in 5th Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 shows a schematic configuration of a printing apparatus employing an ink jet system. The printing apparatus 100 is a transfer type line printing apparatus that forms an intermediate image on the surface of a transfer body serving as an intermediate print medium (intermediate medium) and transfers the intermediate image to a sheet that is a final print medium.

  The printing apparatus 100 is provided with a drum-shaped transfer body 101 having a cylindrical shape, and a printing unit 103 that prints an image by ejecting liquid facing the peripheral surface (cylindrical curved surface) of the transfer body 101. ing. In the print unit 103, a plurality of line discharge heads that discharge liquid are arranged radially along the circumferential surface direction (the rotational movement direction of the medium) of the transfer body 101. In each ejection head, a plurality of ejection openings for ejecting liquid are arranged in a long shape in a direction (long direction) orthogonal to the paper surface of FIG. 1, and these ejection openings constitute a long ejection opening array. Yes. The liquid ejected from each ejection head includes a plurality of colors of ink for forming an image and a reaction liquid for enhancing the quality of an image formed in response to the ink.

  When forming an image, the transfer body 101 is rotated in the D1 direction, and different colors of ink and a reaction liquid described later are discharged from a plurality of discharge heads provided in the print unit 103. In this example, the transfer body 101 has a diameter of 0.9 m and rotates at a linear velocity of 0.6 m / s, but these numbers are illustrative and not essential. By the rotation of the transfer body 101, the discharge of ink from the discharge head, and the discharge of the reaction liquid, an intermediate image is formed on the surface of the transfer body 101 continuously.

  On the other hand, a rotating body 106 is provided facing the lower part of the transfer body 101. The rotating body 106 rotates in the direction D2 in synchronization with the rotation of the transfer body while the sheet S supplied from a sheet supply unit (not shown) is pressed against the surface of the transfer body 101. As a result, the intermediate image formed on the surface of the transfer body 101 is transferred to the surface of the sheet and conveyed in the conveyance direction D3. After the transfer of the image to the sheet is completed, the surface of the transfer body 101 is cleaned by the cleaning unit 107 to prepare for the next printing operation.

  FIG. 2 is a diagram schematically showing the internal configuration of the printing unit 103 in the printing apparatus 100 shown in FIG. 1 and the configuration of the mist collecting apparatus provided in the printing apparatus 100. In the print unit 103, nine ejection heads 10 to 18 are arranged to face each other with a predetermined interval from the peripheral surface of the transfer body 101. Also, mist collection units 19 to 28 described later are arranged immediately before the ejection head 18, immediately after the ejection head 10, and between the ejection heads 10 to 18, respectively. Liquid is discharged onto the transfer body 101 cleaned by the cleaning unit 107 in accordance with the arrangement order 10, 11, 12,. As described above, the print unit 103 has a basic configuration in which a plurality of mist collecting units and a plurality of ejection heads are alternately arranged radially along the moving direction (curved surface) of the medium (transfer body). In the printing unit 103, a mist collecting unit is arranged on the most upstream side and the most downstream side.

  In the following description, the position where the transfer body 101 leaves the cleaning unit 107 is defined as the reference position 107a, and the direction toward the reference position 107a is away from the reference position 107a in the rotation direction opposite to the rotation direction D1 of the transfer body 101. The direction is the rear. Further, the front is also called upstream and the rear is also called downstream. According to this definition, the ejection head 10 is an ejection head disposed at the most upstream position, and the ejection head 18 is an ejection head disposed at the most downstream position. Further, in the mist collection units 19 to 28 described later, the definitions regarding the front, rear, upstream, and downstream are the same as those of the ejection head.

  Here, the types of the plurality of ejection heads 10 to 18 will be described. The ejection heads 11 to 17 are ink ejection heads that eject droplets of ink. The type (color) of ink is divided for each ejection head. The top discharge head 10 installed at the most upstream is a pretreatment liquid discharge head (reaction liquid discharge head) for discharging a pretreatment liquid (reaction liquid). The pretreatment liquid is preliminarily applied to the image forming portion on the transfer body 101, thereby reacting with the ink droplets subsequently applied to improve the ink cohesion and image quality (glossiness). Is. The rearmost discharge head 18 installed on the most downstream side is a post-processing liquid discharge head (reaction liquid discharge head) that discharges the post-processing liquid (reaction liquid). The post-treatment liquid is applied on the image formed on the transfer body 101, and reacts with the ink to improve the weather resistance and fixability of the image. The distance between these ejection heads 10 to 18 and the transfer body 101 is about 1 mm or less at the narrowest portion.

  Next, the mist collection units 19 to 28 mounted on the printing apparatus 100 will be described. The mist collecting device 200 includes a mist collecting unit 19 to 28 that sucks and collects the mist of the ink and the reaction liquid discharged from the discharge heads 10 to 18, and air suction and discharge for collecting the mist in the mist collecting unit. And a suction / discharge mechanism 300 for performing the above.

  First, the mist collection units 19 to 28 will be described. The printing apparatus 100 is provided with three types of mist collection units 500, 600, and 700. The mist collection units 19 and 20 use a first mist collection unit (first mist collection unit) 500. In addition, a second mist collection unit (second mist collection unit) 600 is used for the mist collection units 21 to 25. Further, a third mist collection unit (first mist collection unit) 700 is used for the mist collection units 26 to 28. The first mist collection unit 500 (19, 20) and the third mist collection unit 700 (26 to 28) are both configured to generate a blown airflow and a suction airflow, and are in the air by the blowout airflow and the suction airflow. Aspirate and collect mist floating on the surface. The second mist collection unit 600 (21 to 25) has a configuration that only sucks air, and sucks and collects mist floating in the air by the suction airflow generated here.

  Two types of mist collection units (first mist collection unit 500 and third mist collection unit 700) using the blown airflow and the suction airflow are compared with each other when the mist leaks to the already printed area side of the mist collection unit. Are arranged adjacent to each other in front of and behind the ejection head, which causes a significant influence. In particular, the mist of the pretreatment liquid generated from the pretreatment liquid discharge head 10 has a characteristic that it adheres in response to ink. For this reason, when the mist of the pretreatment liquid reaches the ejection heads 11 to 17 and the post-treatment liquid ejection head 18, it adheres to the ejection port of the ejection head or the surface on which the ejection port is formed (ejection surface). There is a risk of causing a discharge failure and image degradation. Further, if the mist of the pretreatment liquid leaks forward, there is a concern that the printing apparatus 100 may float and adhere to various places. Therefore, the first mist collection unit 500 is applied to the mist collection units 19 and 20 disposed before and after the pretreatment liquid discharge head 10 to generate a blown air flow and a suction airflow before and after the pretreatment liquid discharge head 10. It is supposed to let you. According to this, the leakage of the mist generated from the pretreatment liquid discharge head 10 in the front-rear direction can be blocked by the blown airflow acting as an air curtain, and the floating mist is recovered by the first mist recovery. It can be sufficiently recovered by the suction airflow of the parts 19 and 20.

  Furthermore, the mist of the pretreatment liquid may adhere to the discharge port surface of the pretreatment liquid discharge head 10 itself that has discharged the pretreatment liquid, and may cause a discharge failure at the discharge port. In order to suppress the mist of the pretreatment liquid from adhering to the ejection port surface of the pretreatment liquid ejection head 10, an air flow is allowed to flow between the ejection head and the print medium from the unprinted area side of the ejection head. It is valid. Therefore, a first mist collection unit 19 is applied to the first mist collection unit 19 disposed in front of the pretreatment liquid discharge head 10 (on the unprinted area side). Thereby, a part of the blown air flow blown out from the first mist collecting unit 19 flows between the transfer body 101 and the discharge head, and the mist of the pretreatment liquid is discharged to the discharge port surface of the pretreatment liquid discharge head 10. It can suppress adhering.

  Further, when the mist of the post-processing liquid generated from the post-processing liquid discharge head 18 reaches the ink discharge heads 11 to 17, the pre-processing liquid discharge head 10, etc., the mist of the post-processing liquid adheres to the discharge port surfaces and discharge ports of those discharge heads. , May cause discharge failure. Furthermore, if the mist of the post-processing liquid leaks behind (downstream) the post-processing liquid ejection head 18, there is a concern that the printing apparatus 100 may float and adhere to the internal mechanism. Therefore, the third mist collection unit 700 that generates the blown airflow and the suction airflow is also applied to the mist collection units 27 and 28 disposed before and after the post-processing liquid discharge head 18. According to this, it is possible to more reliably collect the mist of the post-processing liquid generated from the post-processing liquid discharge head 18 by using the blown air flow and the suction air flow generated by the mist collecting units 27 and 28. Become. Further, a part of the air flow generated from the mist collecting unit 27 flows between the discharge port surface of the post-processing liquid discharge head 18 and the transfer body 101, thereby discharging the post-processing liquid itself. It is also possible to suppress the mist from adhering to the discharge port surface.

  In the present embodiment, the discharge head disposed at the most downstream position in the print unit 103 is a post-processing liquid process head. However, it is desirable to install the third mist collection unit 700 even when the ejection head arranged at the most downstream position is an ink ejection head. That is, when the discharge head arranged at the most downstream position is an ink discharge head, the ink mist generated from the ink discharge head leaks backward and floats inside the printing apparatus and adheres to various parts. Is concerned. For this reason, even when the ejection head arranged at the most downstream position is an ink ejection head, the third mist collection unit 700 is applied to the mist collection units arranged before and after the ejection head. According to this, it becomes possible to more reliably suppress the leakage of the ink mist to the downstream side.

  Furthermore, a third mist collection unit 700 that uses a blown airflow and a suction airflow may be disposed before and after the ejection head that is assumed to generate a large amount of mist. In the present embodiment, since it is assumed that the ink discharge head 17 generates a larger amount of mist than the other discharge heads, the blown airflow and suction are also supplied to the mist collection unit 26 disposed in front of the ink discharge head 17. A third mist collecting unit 700 that generates airflow is applied. Therefore, even when a large amount of ink mist is generated from the ejection head 17, the ink mist can be more reliably collected by the third mist collecting units 26 and 27 having a high mist collecting capability. Furthermore, when a part of the blown airflow generated from the mist collecting unit 26 flows into the lower portion of the ink discharge head 17, it is possible to suppress the mist from adhering to the discharge port surface of the ink discharge head 17.

  The second mist collecting unit 600 that generates only the suction airflow is used when the amount of mist generated from the discharge head is small. However, when it is desired to perform mist recovery more reliably, the first mist recovery unit 500 or the third mist recovery unit 700 that generates the blown airflow and the suction airflow can be used. The second mist collection unit 600 can be shorter in width (length in the rotation direction 111 of the transfer body 101) than the first and third mist collection units. As a result, the distance between adjacent ejection heads can be reduced, and the printing apparatus can be configured in a compact manner. In addition, since the second mist collection unit 600 does not generate a blown airflow, the total air volume for mist collection can be suppressed.

  Next, the suction / discharge mechanism 300 will be described. A suction / discharge mechanism 300 is connected to the mist collection unit, and intake and exhaust are performed in the mist collection unit by the intake force and exhaust force generated here. The suction / discharge mechanism 300 includes a pump 33 (air supply means), a pump 36 (intake means), a pump 39 (discharge means), flow rate adjusting valves 32, 35, and 38, and pipes 29, 30, and 31. . The pipe 29 is installed to supply air to the mist collecting units 19, 20, 26, 27, and 28, and the pipe 30 is installed to suck air from the mist collecting units 19 to 28. Further, the pipe 31 includes a liquid in which the mist collected in the mist collecting units 19 to 28 gathers, a cleaning liquid for cleaning the inside (hereinafter, these liquids are collectively referred to as waste liquid), and air containing the mist. It is a pipe for discharging (hereinafter referred to as waste air) to the outside.

  The pipe 29 is connected to a pump 33 for supplying air to the first mist collection unit 500 (19, 20) and the third mist collection unit 700 (26, 27, 28). The pipe 30 is connected to a pump 36 that generates a suction force for sucking air from the first, second, and third mist collection units 500, 600, and 700 (19 to 28). Further, the pipe 31 is a pump that generates a suction force for discharging together with waste air waste liquid in which liquid collected by the mist collected in the mist collecting sections 19 to 28 and cleaning liquid for cleaning the mist collecting section are mixed. 39. Further, valves 32, 35, and 38 for adjusting the flow rate of the fluid flowing inside are connected to the pipes 29, 30, and 31, respectively. Further, between the valves 35 and 38 and the mist collection units 19, 20, and 26 to 28, cleaning mechanisms 34 and 37 for removing dust and the like contained in the waste liquid and waste air are connected to the pipes 30 and 31. Has been.

FIGS. 3A and 3B are perspective views showing the appearance of the first, second, and third recovery units. FIG. 3A shows the first recovery unit 500, FIG. 3B shows the second recovery unit 600, and FIG. ) Shows the third collection unit 700, respectively.
The first mist collection unit 500 includes a substantially rectangular parallelepiped casing 501 (first casing) having a width d1. Inside the housing 501, spaces such as a pressure chamber and a flow path described later are defined. A slit-like suction hole 40 and a blowout hole 56 are formed in the bottom wall 502 of the housing 501 in parallel with each other. The suction holes 40 and the blowout holes 56 are formed over a range that is equal to or longer than the length of the discharge port array 91 formed in the discharge heads 10 to 18. The side wall 503 of the housing 501 is provided with an exhaust hole (first exhaust hole) 49, an air supply hole (first air supply hole) 50, and a waste liquid discharge hole (first waste liquid discharge hole) 41. . The exhaust hole 49 is connected to the pipe 30, the air supply hole 50 is connected to the pipe 29, and the waste liquid discharge hole 41 is connected to the pipe 31.

  The second mist collecting unit 600 includes a substantially rectangular parallelepiped housing 601 (second housing) having a width d2 narrower than that of the first mist collecting unit 500. A pressure chamber, a flow path, etc., which will be described later, are defined inside the housing 601. A slit-like suction hole 60 is formed in the bottom wall 602 of the housing 601 over a range that is greater than or equal to the length of the discharge port array 91 formed in the discharge heads 10 to 18. The side wall 603 of the housing 601 is provided with an exhaust hole (second exhaust hole) 69 and a waste liquid discharge hole (second waste liquid discharge hole) 61. The exhaust hole 69 is provided in the pipe 30, and the waste liquid discharge hole 61 is provided. Each is connected to a pipe 31.

  The third mist collecting unit 700 has a substantially rectangular parallelepiped casing 701 (third casing) having a width d3. In the bottom wall 702 of the housing 701, a slit-like suction hole (first suction hole) 70, a blow-out hole (blow-out hole) are provided in substantially the same manner as the suction hole 40 and the blow-out hole 56 in the first mist collecting unit 500. 86 is provided. The side wall 703 of the housing 701 is provided with an exhaust hole (first exhaust hole) 79, an air supply hole (first air supply hole) 80, and a waste liquid discharge hole (first waste liquid discharge hole) 71. ing. The exhaust hole 79 is connected to the pipe 30, the air supply hole 80 is connected to the pipe 29, and the waste liquid discharge hole 71 is connected to the pipe 31.

  FIG. 4 is a longitudinal side view showing the internal structure of each of the first, second, and third mist collection units 500, 600, and 700. FIG. 4A shows the first mist collection unit 500, and FIG. Shows the second mist collection unit 600, and (c) shows the third mist collection unit 700, respectively.

The first mist collecting unit 500 shown in FIG. 4A has a structure 500A for sucking air containing mist and an air current by a separation wall 505 that bisects the interior in the front-rear direction (left-right direction in FIG. 4). It is separated into a structure part 500B for blowing out water.
First, the structure part 500A for sucking in air containing mist will be described. In the structure portion 500A, a suction flow path 43 communicating with a suction hole 40 formed in the bottom portion of the housing 501, a waste liquid holding portion (holding portion) 42, first and second pressure chambers (pressure chambers) 46, 48. Etc. are defined in a state where they communicate with each other. The second pressure chamber 48 communicates with the pipe 30 through an exhaust hole 49 formed in the side wall 503 of the housing 501. Accordingly, the air in the second pressure chamber 48 is discharged to the outside through the pipe 30 by the suction force of the pump 36. As the air in the second pressure chamber 48 is discharged, the air in the structure portion 500 </ b> A flows toward the exhaust hole 49. As a result, external air is sucked from the suction hole 40 into the structure portion 500A.

  The air sucked from the suction hole 40 passes through the suction flow path 43, and a part is blown to the mist trap surface 44 which is the surface of the plate member provided inside the housing 501. Part of the sprayed mist adheres to the mist trap surface 44 that protrudes obliquely downward from the separation wall 505. When the amount of mist attached increases, the mist collects and becomes liquid (waste liquid), which is dropped from the mist trap surface 44 and held in the waste liquid holding unit 42. A waste liquid discharge hole 41 is provided in a side wall 503 (see FIG. 3) of the housing 501 in the first mist collecting unit 500. The waste liquid discharge hole 41 is connected to the pump 39 via the pipe 31 and the pump 39 is driven at a predetermined timing, so that the waste liquid, waste air, the cleaning liquid of the casing, and the like held in the waste liquid holding part 42 are discharged into the waste liquid holding part 42. Discharged from. The waste liquid and waste air discharged from the waste liquid holding part 42 are cleaned by the cleaning mechanism 37, then pass through the valve 38 and discharged from the pump 39 to the outside.

  On the other hand, the air that has flowed into the suction flow path 43 is a first pressure equalizing member 45 provided to make the suction flow rate distribution in the longitudinal direction of the mist recovery unit 500 (the direction orthogonal to the paper surface of FIG. 4) uniform. After passing through, flows into the first pressure chamber. The first pressure chamber 46 is also installed in order to make the suction flow rate distribution in the longitudinal direction closer to each other. The pressure equalizing member and the pressure chamber will be described later with reference to FIG. The air that has flowed into the first pressure chamber 46 further passes through the second pressure equalizing member 47 and flows into the second pressure chamber 48. The second pressure chamber 48 communicates with an exhaust hole 49 provided in the side wall 503 of the mist recovery unit 500. For this reason, the air flowing into the second pressure chamber 48 is discharged from the exhaust hole 49 to the pipe 30 (see FIG. 2). The air that has flowed into the pipe 30 is collected and purified by the cleaning mechanism 34, passes through the valve 35, and is discarded from the pump 36 to the outside.

  Next, the structure part 500B for blowing out air will be described. In the structure portion 500B, a third pressure chamber 51, a fourth pressure chamber 53, and an outlet channel 55 are defined so as to communicate with each other. The third pressure chamber 51 communicates with the pipe 29 through the air supply hole 50 formed in the side wall 503 of the housing 501. For this reason, the air sent from the pump 33 passes through the pipe 29 and the valve 32 and then flows into the third pressure chamber 51 from the air supply hole 50. The 3rd pressure chamber 51 is installed in order to equalize the blowing flow rate distribution of the longitudinal direction of a mist collection unit. The air flowing into the third pressure chamber 51 passes through the third pressure equalizing member 52, the fourth pressure chamber 53, and the fourth pressure equalizing member 54, and the blowout flow distribution in the longitudinal direction is further increased. It is made uniform and sent to the blowout flow passage 55 and blown out from the blowout hole 56. The blown air is blown onto the surface of the transfer body 101.

  The second mist recovery unit 600 shown in FIG. 4B includes a suction flow path 63 that communicates with a suction hole 60 formed in the bottom wall 602 of the housing 601, a fifth pressure chamber 66, and a sixth pressure. A chamber 68 is formed. The sixth pressure chamber 68 communicates with the pipe 30 via a suction hole 60 formed in the side wall 603 of the housing 601, and the air in the sixth pressure chamber 68 is released to the outside by the suction force of the pump 36. Discharged. By discharging the air in the sixth pressure chamber, the air in the second mist collecting unit 600 flows toward the exhaust hole 69. As a result, external air is sucked into the second mist collecting unit 600 from the suction hole 40.

  The air sucked from the suction hole 40 passes through the suction flow path 43 and a part thereof is blown to the mist trap surface 64. Part of the sprayed mist adheres to the second mist trap surface 64 protruding obliquely downward from the side wall of the housing 601, and when the amount of adhesion increases, it becomes liquid (waste liquid) from the mist trap surface 64. The liquid is dropped and held in the waste liquid holding unit 62. A waste liquid discharge hole 61 is provided in the side wall 603 of the housing 601 of the second mist collection unit 600. The waste liquid discharge hole 61 is connected to the pump 39 via the pipe 31, and the waste liquid and waste gas held in the waste liquid holding part 62 are discharged from the waste liquid holding part 62 by driving the pump 39 at a predetermined timing. . The waste liquid and waste air discharged from the waste liquid holding unit 62 are cleaned by the cleaning mechanism 37 and then passed through the valve 38 and discharged from the pump 39 to the outside.

  The third mist collecting unit 700 shown in FIG. 4C has a structure 700A and an air current for sucking in air containing mist by a separation wall 705 that bisects the inside in the front-rear direction (left-right direction in FIG. 4). It is separated into a structure portion 700B for blowing out.

  In the structure portion 700A, a suction flow path 73 communicating with the suction hole 70, a waste liquid holding portion 72, a first pressure chamber 76, a second pressure chamber 78, and the like are defined in a state of communicating with each other. The first pressure chamber 78 communicates with the pipe 30 via the exhaust hole 79, and the waste liquid holding part 72 communicates with the pipe 31 via the waste liquid discharge hole 71.

  When the air in the second pressure chamber 78 is discharged to the outside by the suction force of the pump 36, the air in the structure portion 700 </ b> A flows toward the exhaust hole 79. Along with this, external air is sucked from the suction hole 70 into the structure 700A. The mist contained in the air sucked from the suction hole 70 adheres to the mist trap surface 74 provided in the suction flow path 73, and then liquefies and becomes liquid (waste liquid) and drops into the waste liquid holding unit 72, Retained. The waste liquid is sucked into the pipe 31 by driving the pump 39, cleaned by the cleaning mechanism 37, and then discharged from the pump 39 through the valve 38.

  The air flowing into the suction flow path 73 from the suction hole 70 passes through the first pressure equalizing member 75, the first pressure chamber 76, and the second pressure equalizing member 77, and the second pressure chamber 78. Flow into. The air flowing into the second pressure chamber 78 is discharged from the exhaust hole 79 to the pipe 30, cleaned by the cleaning mechanism 34, passes through the valve 35, and is discharged from the pump 36 to the outside.

  On the other hand, the third and fourth pressure chambers 81 and 83, the blowout flow path 85, and the like are defined in the structure portion 700B in a state where they communicate with each other. The third pressure chamber 81 is connected to the pipe 29 through an air supply hole 80 formed in the side wall 703 of the housing 701. Therefore, after the air sent from the pump 33 flows into the third pressure chamber 81 of the structural portion 700B from the air supply hole 80, the third pressure equalizing member 82, the fourth pressure chamber 83, and the fourth pressure chamber The air is blown out from the blowout hole 86 through the pressure equalizing member 84 and the blowout flow path 85. The blown air is blown onto the surface of the transfer body 101.

  In the present embodiment, the first mist collecting unit 500 is used as the mist collecting units 19 and 20, the second mist collecting unit 600 is used as the mist collecting units 21 to 25, and the third mist collecting unit is used as the mist collecting units 26 to 28. 700 is used. However, it is also possible to use the first, second, and third mist collection units in a combination different from the above embodiment. For example, when it is desired to collect the mist more reliably, the first mist collection unit 500 can be used for the mist collection units 19 to 23 and the third mist collection unit 700 can be used for the mist collection units 24 to 28. .

  FIG. 5 is a cross-sectional view showing the configuration of the pressure chamber and the pressure equalizing member in the first mist recovery unit 500 shown in FIG. 4A, and FIG. 5A is a cross-sectional view taken along the line VA-VA in FIG. FIG. 4B is a cross-sectional view taken along line VB-VB in FIG. As described above, the first and second pressure equalizing members 45 and 47 and the first and second pressure chambers 46 and 48 equalize the suction flow distribution in the longitudinal direction in the first mist recovery unit 500. Use for.

  The first pressure equalizing member 45 is provided between one end portion of the wall portion for defining the first pressure chamber 46 and the suction flow path 43 and the separation wall 505, and the second pressure equalizing member 45 is provided. The member is provided between one end portion of the wall portion for defining the first pressure chamber 46 and the second pressure chamber 48 and the front surface portion of the housing. Each of the first and second pressure equalizing members is a member that forms a space extending in the longitudinal direction, and an upper surface portion and a lower surface portion that form the space are illustrated in FIGS. A plurality of through holes 207 and 208 as shown in b) are formed. In the present embodiment, the opening width wo of the through holes 207 and 208 is about 1 mm. By passing through these through holes 207 and 208, the air is dispersed in the longitudinal direction, and the pressure of the passing air is made uniform.

  In addition, since the first and second pressure chambers form spaces extending in the longitudinal direction, the air flowing into each space is evenly distributed in the longitudinal direction, which also makes the air pressure uniform. Can be achieved.

  The first and second pressure equalizing members and the first and second pressure chambers in the first mist recovery unit have been described above. The configurations and functions of the first and second pressure equalizing members are as follows. The same applies to the third pressure equalizing member 52, the fourth pressure equalizing member 54, and other pressure equalizing members. The operation of the first and second pressure chambers is the same in the other pressure chambers.

  Further, the number of pressure chambers and pressure equalizing members provided in the mist collecting section is not necessarily limited to a plurality. That is, when the suction flow rate distribution in the longitudinal direction of the suction hole is made uniform by a single pressure equalizing member or a single pressure chamber, it is not necessary to provide a plurality of pressure equalizing members and pressure chambers. Conversely, a pressure equalizing member and a pressure chamber may be added to further uniform the suction flow rate distribution in the longitudinal direction.

  Next, the relationship between the arrangement position of the mist collecting part and the waste liquid holding part, the suction hole and the blowout hole formed in the mist collecting part will be described. As shown in FIG. 4, the first mist collecting unit 500 and the third mist collecting unit 700 are configured such that the positions of the waste liquid holding parts 42 and 72, the suction holes 40 and 70, and the blowout holes 56 and 86 are respectively transferred to the transfer body. 101 is reversed in the rotation direction D1. In the present embodiment, the first mist collection unit 500 is used for the mist collection units 19 and 20, and the third mist collection unit 700 is used for the mist collection units 26, 27, and 28. This is due to the following reason.

  FIG. 6 is a diagram illustrating an example in which the first mist collection unit 500 is applied to the mist collection units 20 and 28. In the figure, the hatched portions V1 and V2 indicate the volume of waste liquid that can be held inside the waste liquid holding section 42 of each of the mist collecting sections 20 and 28. Comparing V1 and V2, it can be clearly seen that the volume of V1 is larger. Now, in the upper half of the transfer body 101, the direction opposite to the rotation direction of the transfer body 101 is set on the upstream side in the order of the vertical line VL passing through the rotation center of the transfer body 101 and perpendicular to the installation floor of the apparatus. The direction is defined as the downstream side. Since the printing apparatus is installed on a floor that can be regarded as horizontal or horizontal, the vertical line VL coincides with the vertical direction (the direction of gravity).

  Here, on the upstream side, if the waste liquid holding part 42 is installed on the upstream side (front side) of the suction hole 40, more mist can be held. Therefore, the first mist collection unit 500 is applied to the mist collection units 19 and 20 arranged on the upstream side from the reference. This makes it possible to reduce the number of times the waste liquid held in the waste liquid holding part 42 is discharged, and to prevent the waste liquid from overflowing from the waste liquid holding part 42 and flowing down from the suction hole 40 onto the transfer body 101. Can be suppressed.

  FIG. 7 is a cross-sectional view showing an example in which the third mist collection unit 700 is applied to the mist collection units 20 and 28. In the drawing, the hatched portions V3 and V4 indicate the volume of waste liquid that can be held inside the waste liquid holding section 72 of each of the mist collecting sections 20 and 28. Comparing V3 and V4 clearly shows that the volume of V4 is larger. That is, if the waste liquid holding part 72 is installed on the downstream side (rear side) of the suction hole (suction hole) 70 on the downstream side, more waste liquid can be held. Therefore, the third mist collection unit 700 is applied to the mist collection units 26, 27, and 28 arranged on the downstream side of the reference. Thereby, it is possible to reduce the number of times of performing the discharge operation of the waste liquid held in the waste liquid holding unit 72. It is also possible to suppress the waste liquid from overflowing from the waste liquid holding part 72 and flowing down from the suction hole 70 onto the transfer body 101.

  On the other hand, FIG. 8 is a sectional view showing an example in which the second mist collection unit 600 is applied to the mist collection units 22 and 25. In the figure, hatched portions V5 and V6 indicate the volume of waste liquid that can be held in the waste liquid holding section 62 of each of the second mist collection units 600 applied to the mist collection sections 22 and 25. In this example, similarly to the example shown in FIG. 6, the second mist collection unit 600 is installed so that the waste liquid holding unit 62 is positioned upstream (front) of the suction hole 60 on the upstream side from the reference. Yes. Further, on the downstream side, as in the example shown in FIG. 7, the second mist collection unit 600 is arranged so that the waste liquid holding unit 62 is located on the downstream side (rear side) of the suction hole 60. According to this, it is possible to secure a sufficient volume of waste liquid that can be held by the waste liquid holding unit 62. Accordingly, also in the second mist collecting unit 600, it is possible to reduce the number of times of performing the discharge operation of the waste liquid held in the waste liquid holding part 62, and the waste liquid overflows from the waste liquid holding part 62 and the suction hole 60. Can be prevented from flowing onto the transfer body 101.

  The first, second, and third mist collecting units 500, 600, and 700 are preferably provided with a gap between the ejection heads 10 to 18 or the metal fittings that hold the ejection heads 10 to 18. . By providing such a gap, airflow flows from the gap, so that it is possible to suppress the mist from adhering to the transfer body 101 and the opposing surface of the mist collecting section with respect to the transfer body 101. In particular, it is effective to provide a gap 90 between the discharge head or a member that holds the discharge head and the second mist collection unit 600. In other words, the second mist collecting unit 600 is not provided with a blowout hole, but by providing the gap 90, this serves as a blowout hole. For this reason, air is smoothly sucked into the suction hole 60, and the airflow blown out from the gap 90 reaches the transfer body 101, thereby substantially acting as a blown airflow. For this reason, it becomes possible to collect mist efficiently.

  FIG. 9 is a cross-sectional view showing the positional relationship between the first mist collecting unit 500 and the transfer body. With respect to the vertical line VL passing through the center of rotation of the transfer body 101, an angle formed by the vertical line VL and the center line L1 of each of the transfer body 101 and the mist collecting units 20 and 28 is defined as θ. Further, with reference to the vertical line VL passing through the rotation center of the transfer body 101, the reverse direction to the rotation direction of the transfer body 101 is the upstream side, the forward direction is the downstream side, and the center line L1 and the vertical line VL located upstream The angle formed by is defined as a positive angle. Furthermore, the angle formed by the center line L1 located on the downstream side and the vertical line VL is a negative angle. The length of the side wall part 42a of the waste liquid holding part 42 inside the mist collecting part is set to H. In addition, the side wall part 42a shall be extended in the direction orthogonal to the bottom wall 502 of the 1st mist collection | recovery unit 500. FIG. Here, by increasing H as the absolute value of the angle θ increases, it becomes possible to increase the amount of waste liquid that can be held in the waste liquid holding part 42. Alternatively, when the absolute value of −θ increases, it becomes possible to increase the amount of mist that can be held inside the waste liquid holding unit by increasing H. Although FIG. 9 shows the first mist collection unit 500, the same applies to the second and third mist collection units 600 and 700. That is, the lengths of the side wall portions 62a and 72a (see FIGS. 4B and 4C) extending in the direction orthogonal to the bottom walls 602 and 702 of the waste liquid holding portions 62 and 72 are changed according to the angle. You may do it. According to this, it is possible to optimize the mist holding amount of the waste liquid holding unit.

  FIG. 10 is a cross-sectional view showing an example in which the first mist collection unit 500 is applied to the mist collection unit 20, and shows the positional relationship among the first mist collection unit 500, the transfer body 101, and the ejection head 10. ing. A straight line (center line) L1 connecting the center of the ejection head 10 located on the upstream side of the mist collection unit 20 and the rotation center of the transfer body 101, the center of the suction hole 40 of the mist collection unit 20 and the rotation center of the transfer body 101. An angle formed by a straight line L2 connecting the two is θ1. In order to collect the mist before the mist generated from the ejection head 10 diffuses into the internal mechanism of the printing apparatus, it is desirable to make θ1 as small as possible. That is, it is desirable to bring the center of the ejection head 10 and the center of the suction hole 40 of the mist collection unit 20 as close as possible. However, in order to sufficiently secure the liquid holding volume of the mist that can be held in the waste liquid holding portion 42, it is necessary to secure a certain amount of θ1. Further, the amount of waste liquid to be set in the mist collection unit 20 is determined by the method of discharging the mist from the waste liquid holding unit 42. For example, in the discharge method in which the waste liquid is always discharged from the waste liquid discharge hole 41, the liquid holding volume of the waste liquid holding unit 42 can be reduced to reduce θ1. Further, in the discharge method of intermittently discharging the waste liquid from the waste liquid discharge hole 41, since the waste liquid composed of mist or the like is stored in the waste liquid holding part 42 between the discharge operation, the waste liquid holding part 42 It is necessary to secure a certain liquid holding volume. That is, it is necessary to make the angle of θ1 a certain size. Although the first mist collection unit 500 has been described here, the angle θ1 is appropriately determined for the second and third mist collection units 600 and 700 according to their arrangement positions, the waste liquid discharge method, and the like. Just do it.

  Here, a specific example is shown about the speed of the blowing airflow and suction | inhalation airflow of each mist collection | recovery part, a blowing hole, and the width | variety of a suctioning hole. The widths of the suction holes 40 of the first mist collection unit 500, the suction holes 60 of the second mist collection unit 600, and the suction holes (suction holes) 70 of the third mist collection unit 700 are about 3 to 5 mm, respectively. preferable. Further, the width of the blowout hole 56 of the first mist collection unit 500 and the width of the blowout hole 86 of the third mist collection unit 700 are each preferably about 0.5 to 2 mm. The width of the gap 90 of the second mist collection unit 600 is preferably 0.5 mm or more. The air suction speeds in the suction hole 40 of the first mist recovery unit 500, the suction hole 60 of the second mist recovery unit 500, and the suction hole 70 of the third mist recovery unit 700 are 0.3 to 1.0 m, respectively. About / s is preferable. The flow rate of air blown out from the blowout hole 56 of the first mist collection unit 500 and the blowout hole 86 of the third mist collection unit 700 is preferably about 0.5 to 2.0 m / s.

  FIG. 11 is a plan view of the ejection head 10 and the mist collection unit 20 as viewed from the transfer body 101. The mist of the reaction liquid generated when the reaction liquid is discharged from the discharge port array 91 of the discharge head 10 spreads in the length direction of the discharge port array 91 as shown by the arrow 92 and is transferred to the mist collecting unit 20. Head. Therefore, in order to completely recover the mist, the length of the blowout hole 56 and the suction hole 40 of the mist recovery unit 20 needs to be longer than the length of the discharge port array 91. By making the difference between the lengths of the blowout holes 56 and the suction holes 40 and the lengths of the discharge port arrays 91 more than 20 times the distance between the discharge head 10 and the transfer body 101, good mist recovery can be performed. The inventor confirmed.

  Further, among the discharge heads 10 to 18, in particular, for the mist collection units 19 and 20 disposed before and after the pretreatment liquid discharge head 10 where it is necessary to completely recover the mist, the discharge holes 56 and the suction holes 40 are provided as discharge ports. It was longer than the line. Since the distance between the discharge heads 10 to 18 and the transfer body 101 is about 1 mm or less at the narrowest portion, the difference 93 between the length of the discharge port array 91 and the length of the blowout holes 56 and the suction holes 40 is one side. 20 mm. In the other ejection heads and the mist collection unit, it is desirable to make the lengths of the blowout holes and the suction holes longer than the ejection port array.

  As described above, in the present embodiment, the first and the second before and after the reaction liquid ejection heads 10 and 18 in which the influence due to leakage of mist cannot be ignored and the ink ejection head 17 in which the amount of mist generation may increase. Alternatively, a third mist collecting unit 500 or 700 is arranged. This makes it possible to suppress the reaction liquid mist and ink mist from adhering to the ejection head or the internal mechanism of the printing apparatus, and to reduce the occurrence of ejection failure of the ejection head and the influence on the internal mechanism of the printing apparatus. Is possible. In addition, the first and third mist collecting units 500 and 700 that generate both the suction airflow and the blown airflow are arranged only before and after a specific discharge head, and are relatively small for the other discharge heads. Two mist collecting units 600 are arranged. For this reason, it becomes possible to perform a mist collection | recovery appropriately, suppressing the total air volume required for a mist collection | recovery with a compact structure.

  Generalizing the configuration of the present embodiment, the first mist collection unit included in the plurality of mist collection units is installed to be tilted upstream in the moving direction of the medium with respect to a vertical line perpendicular to the floor, In the first mist collecting unit, the liquid holding portion is provided upstream of the suction hole for sucking the mist. Furthermore, the second mist collecting unit different from the first mist collecting unit is installed inclined to the downstream side in the moving direction with respect to the vertical line, and the second mist collecting unit has a waste liquid holding unit. Is provided downstream of the suction hole. With this configuration, in each of the plurality of mist collection units, the holding unit can hold the liquid with a sufficient capacity, and the liquid in which the mist is liquefied is suppressed from dripping onto the medium.

  Further, when the configuration of the present embodiment is generalized from another viewpoint, the plurality of ejection heads include an ink ejection head that ejects ink and a reaction liquid ejection head that ejects a reaction liquid that reacts with ink, and is the most in the moving direction of the medium. A reaction liquid discharge head is disposed on at least one of the upstream and downstream sides. A mist recovery unit having an air blowing hole and an air suction hole at the bottom of the housing is provided adjacent to the upstream and downstream sides of the reaction liquid discharge head. With this configuration, since the mist of the reaction solution is efficiently recovered immediately after generation, adhesion of the reaction solution mist to the surroundings is suppressed. When the reaction liquid mist is mixed with the ink mist, the reaction liquid mist is easily fixed as a strong stain. By collecting the mist so as to shield the upstream and downstream sides of the reaction liquid discharge head as in this configuration, it is possible to suppress the mist from flowing from the reaction liquid discharge head to the adjacent ink discharge head, and to have strong dirt near the head discharge port. Is prevented from sticking.

(Second Embodiment)
FIG. 12 is a cross-sectional view showing the second embodiment, where (a) is a first mist collection unit 500, (b) is a second mist collection unit 600, and (c) is a third mist collection unit. 700 are shown. Porous bodies 201, 202, and 203, which are ink absorbers, are accommodated in the waste liquid holding units (holding units) 42, 62, and 72 of the first, second, and third mist collection units 500, 600, and 700, respectively. ing. Thereby, since the waste liquid in the waste liquid holding parts 42, 62, 72 is absorbed and held by the porous body, leakage of the waste liquid to the suction holes 40, 60, 70 is suppressed. According to the present embodiment, the amount of waste liquid that can be retained is determined by the volume of the porous body. For this reason, it becomes possible to hold | maintain the fixed amount of waste liquid according to the volume of a porous body irrespective of the arrangement position of a mist collection | recovery part. The range in which the porous body is disposed may be extended to a position in contact with the first pressure equalizing member 45, the fifth pressure equalizing member 65, and the seventh pressure equalizing member 75. Further, since the porous body acts as a resistance element of the fluid, the flow distribution of the blown air flow and the suction air flow can be made more uniform by providing the porous body.

(Third embodiment)
FIG. 13 is a diagram schematically showing the internal configuration of the printing unit 103 and the configuration of the mist collecting apparatus according to the third embodiment. As in the first embodiment, the nine ejection heads 10 to 18 face the print unit 103 from the surface of the transfer body 101 with a predetermined interval (the narrowest portion is about 1 mm or less). Has been placed. The ejection head 10 is a pretreatment liquid ejection head that ejects a pretreatment liquid, and the ejection heads 11 to 18 are ink ejection heads that eject ink.

  In addition, mist collection units 19 to 28 described later are disposed immediately before the discharge head 10, immediately after the discharge head 18, and between the discharge heads 10 to 18. A first mist collection unit 500 that generates a blown airflow and a suction airflow is applied to the mist collection units 19 and 20 disposed before and after the pretreatment liquid discharge head 10. Further, since the ejection head 18 is the last head of the printing unit 103, if the mist leaks from here, the mist floats in the ink jet printing apparatus and may adhere to various portions of the printing apparatus. Concerned. Therefore, a third mist collection unit 700 that generates a blown airflow and a suction airflow is applied to the mist collection unit 28 disposed behind the ejection head 18. The other mist collecting units 21 to 27 are provided with a second mist collecting unit 600 that uses a suction airflow. Other configurations are the same as those of the first embodiment.

  With the above configuration, the first and third mist collecting units that generate the blown air flow and the suction air flow only before and after the discharge heads 10 and 18 and behind the discharge head 18 where the influence of mist leakage cannot be ignored. 500 and 700 were used. For this reason, it becomes possible to perform a mist collection | recovery appropriately with a compact structure, suppressing the total air volume of the whole.

(Fourth embodiment)
FIG. 14 is a diagram schematically illustrating the internal configuration of the printing unit 103 and the configuration of the mist collecting apparatus according to the fourth embodiment. The same or corresponding parts as those in the first embodiment are denoted by the same reference numerals.

  In the present embodiment, similarly to the first embodiment, nine ejection heads 10 to 18 are arranged along the surface of the transfer body 101. The ejection heads 10 to 17 are ink ejection heads, and the ejection head 18 is a post-treatment liquid ejection head that ejects a post-treatment liquid. The mist collection units 27 and 28 provided before and after the post-processing liquid discharge head 18 are provided with a third mist collection unit 700 having a high mist leakage suppression effect. Moreover, the small 2nd mist collection | recovery unit 600 which uses only a suction | inhalation airflow was arrange | positioned in the mist collection | recovery parts 19-26.

  With the above configuration, the third mist collecting unit 700 that generates the blown airflow and the suction airflow is used only before and after the discharge head 18 where the influence of mist leakage cannot be ignored. For this reason, it becomes possible to perform a mist collection | recovery appropriately with a compact structure, suppressing the total air volume of the whole.

(Fifth embodiment)
In the above-described embodiment, the printing apparatus that transfers and prints the image formed on the peripheral surface of the cylindrical transfer body 101 on the sheet S as the inkjet printing apparatus according to the present invention has been described. However, the present invention is not limited to the one using a cylindrical drum-shaped transfer body. For example, it can be applied to a transfer system that forms an image on a rotating transfer body such as a belt, or a direct drawing system printing apparatus that forms an image directly by applying ink to a moving sheet (print medium). is there.

  FIG. 15 is a diagram illustrating a schematic configuration of an inkjet printing apparatus that employs a direct drawing method in which an image is directly formed by a printing unit 803 on a sheet S (print medium) that moves along a planar direction D5. In the printing unit 803, the ejection heads 810 to 818 are arranged along a plane parallel to the sheet S moving on the plane. The discharge head 810 provided at the most upstream position in the moving direction D5 of the sheet S is a pretreatment discharge liquid head, and the discharge head 818 provided at the most downstream position of the sheet S is a post treatment liquid head. In addition, seven ejection heads 811 to 817 arranged between the pretreatment liquid ejection head 810 and the posttreatment liquid ejection head 818 are ink ejection heads that eject ink. The sheet S is not limited to a form that moves along a plane, but may be a form that moves along a curved surface.

  Mist collection units 819 to 828 are sequentially arranged along the moving direction D5 of the sheet S so as to be positioned before and after each ejection head. A first mist collecting unit 500 using a blown airflow and a suction airflow is applied to the mist collecting portions 819 and 820 arranged before and after the pretreatment liquid discharge head 810. In addition, the mist collection unit 826, 827, and 828 disposed before and after the post-treatment liquid discharge head 818 and the ink discharge head 817 where a large amount of mist is expected to be discharged is used to collect mist using a blown air flow and a suction air flow. Unit 700 is applied. Further, a second mist collection unit 600 similar to that of the first embodiment is applied to the mist collection unit disposed between the other ink ejection heads 811 to 816. In addition, when installing an ejection head and a mist collection | recovery part on a plane like this embodiment, two types of mist collection | recovery parts (1st mist collection | recovery) are used as a mist collection part using a blowing airflow and a suction | inhalation airflow. Either unit 500 or third mist collection unit 700) may be used. That is, one type of mist collecting unit (third mist collecting unit 700) is applied to the mist collecting units 819 and 820, and the other type of mist collecting unit (first mist collecting unit (first mist collecting unit 700) is applied to the mist collecting units 826, 827, and 828. One mist collection unit 500) may be applied.

  As described above, even in a printing apparatus that prints directly on a sheet-like print medium, the suction air flow and the jet air flow are only applied before and after the discharge head, where the influence of mist leakage cannot be ignored. By using the used mist collection | recovery part, it becomes possible to suppress the outflow of mist. In addition, the printing apparatus can be configured compactly, and the total air volume for collecting mist can be suppressed.

10 Pretreatment liquid discharge head (Reaction liquid discharge head)
11-17 Ink discharge head 18 Post-treatment liquid discharge head (reaction liquid discharge head)
19-28 Mist collection part 40, 70 Suction hole 42, 62, 72 Waste liquid holding part (holding part)
56, 86 Blowout hole 101 Transfer body (medium)
500 First mist collection unit (first mist collection unit)
501, 701 Case (first case)
600 Second mist collection unit (second mist collection unit)
601 housing (second housing)
700 Third mist collection unit (first mist collection unit)

Claims (12)

A printing apparatus in which a plurality of ejection heads including an ink ejection head that ejects ink and a reaction liquid ejection head that ejects a reaction liquid that reacts with the ink is disposed along a moving direction of the medium,
The reaction liquid discharge head is disposed on at least one of the most upstream and the most downstream in the moving direction among the plurality of discharge heads,
A printing apparatus comprising: a mist collecting unit provided with an air blowing hole and an air suction hole at a bottom portion of the casing adjacent to the upstream side and the downstream side of the reaction liquid discharge head, respectively. .   A plurality of the inks of different colors between a first reaction liquid discharge head that is provided in the uppermost stream and discharges the pretreatment liquid and a second reaction liquid discharge head that is provided in the most downstream area and discharges the posttreatment liquid. The printing apparatus according to claim 1, wherein an ejection head is disposed along the moving direction.   The mist recovery unit is provided adjacent to the upstream and the downstream of the first reaction liquid discharge head, and the mist recovery unit is provided adjacent to the upstream and the downstream of the second reaction liquid discharge head. The printing apparatus according to claim 2, wherein the printing apparatus is a printer.   Between the plurality of adjacent ink discharge heads among the plurality of ink discharge heads, another mist collecting unit provided with an air suction hole at the bottom of the housing and not provided with an air blowing hole is provided. The printing apparatus according to claim 2, wherein the printing apparatus is provided.   The printing apparatus according to claim 4, wherein a gap for supplying air toward the medium is formed between the another mist collecting unit and a member adjacent thereto.   In the mist collecting unit, the blowout holes and the suction holes each have a long slit in a direction orthogonal to the moving direction, and the length of each slit is the length of the discharge port array of the adjacent discharge heads. The printing apparatus according to claim 1, wherein the printing apparatus is longer than the length.   The mist collection unit holds a liquid obtained by liquefying a casing, the blowout holes and the suction holes provided in the bottom of the casing, and the mist provided in the casing and sucked from the suction holes. The printing apparatus according to claim 1, further comprising a holding unit.   The printing apparatus according to claim 7, wherein an absorber that absorbs liquid is accommodated in the holding unit.   The printing apparatus according to claim 7, further comprising a discharge unit that discharges the waste liquid held in the holding unit to the outside of the casing.   The casing has a long shape in the same direction as the long direction of the discharge head, and has a pressure chamber for making the suction flow rate distribution of air in the suction hole close to uniform. Item 10. The printing apparatus according to any one of Items 7 to 9. The medium is a cylindrical transfer body, and intermediate images formed by the plurality of ejection heads on the peripheral surface of the transfer body are transferred to a sheet,
The printing apparatus according to claim 1, wherein the mist collection unit and the discharge head are alternately arranged along a circumferential surface direction of the transfer body. The medium is a moving sheet, and an image is formed on the sheet by the plurality of ejection heads.
The printing apparatus according to claim 1, wherein the mist collection unit and the discharge head are alternately arranged along the movement direction.

Images