JP5884558B2 - Mist collection device and liquid discharge device - Google Patents

Description

  The present invention relates to a mist collecting device and a liquid discharging device that collect liquid mist generated by discharging liquid from a nozzle.

  A printer that sucks mist into a collection device is known (see Patent Document 1). In Patent Document 1, mist sucked into the collection device is collected by a filter.

JP2011-62982A

However, in Patent Document 1, there is a problem that ink droplets in the collection device leak out of the collection device and drop onto the printing paper.
The object of the present invention has been made in view of the above problems, and an object of the present invention is to provide a technique for preventing the liquid droplets from being dropped.

  In order to solve the above problems, the mist collecting apparatus of the present invention includes a suction container that forms a flow path of air sucked from the suction port, with a suction port formed within a predetermined distance from the nozzle as a lower end. The suction device generates an air flow upward from the suction port in the suction container. Thereby, the air containing the liquid mist generated at the nozzle can be sucked from the suction port, and the air can be guided upward. The guide wire is formed in a vertical line on the wall surface constituting the flow path of the suction container. The guide wire is more liable to hold liquid than other regions on the wall surface.

  In the above configuration, the liquid droplets can be held in a limited region on the guide line, and the liquid droplets can be aggregated on the guide line. The droplet receives an air resistance corresponding to the projected area of the droplet in the direction of the airflow, and moves upward by the air resistance. Since the guide line is easier to hold the droplet than the other regions on the wall surface, the droplet moves on the guide line. Since the guide line is linear in the vertical direction, the droplet can be guided upward on the guide line. Therefore, the liquid can be moved upward from the suction port formed at the lower end of the suction container, and the liquid can be prevented from dripping from the suction port.

  Specifically, the guide wire may be a linear groove formed on a planar wall surface. In the groove, the contact area with the droplet can be made larger than that in the other planar region. Therefore, by using the guide wire as a groove, it is easier to hold the liquid in the guide wire than in other regions on the wall surface.

  Further, the guide wire may be a wire that has been subjected to a surface treatment that makes liquid wettability better than other regions on the wall surface. For example, the guide wire may be applied in a linear shape with a material having good liquid wettability. Further, the surface roughness of the wall surface may be adjusted so as to improve the wettability of the liquid.

  Further, the guide wire may be formed in a branch line shape that branches downward on the wall surface. Since the guide lines merge upward, the droplets can be agglomerated as they move upward on the guide line.

  Furthermore, the technique for collecting mist as in the present invention is also applicable as a method. In addition, the apparatus and method described above may be realized as a single apparatus or may be incorporated into an apparatus having multiple functions.

It is a block diagram of a printer. (2A) is a schematic cross-sectional view of the suction container, (2B) is a view showing the wall surface of the suction portion, and (2C) is a bottom view of the suction portion. (3A) and (3B) are schematic diagrams showing how droplets are formed on a guide line. (4A) is a bottom view of the suction part of the first modification, and (4B) is a view showing a wall surface of the suction part of the second modification.

Here, embodiments of the present invention will be described in the following order.
(1) Printer configuration:
(2) Modification:

(1) Printer configuration:
FIG. 1 is a block diagram illustrating a configuration of a printer 1 as a liquid ejection apparatus including a mist collecting apparatus according to an embodiment of the present invention. The printer 1 includes a supply unit 10, a printing unit 11, a collection unit 12, and an ejection head 13. The supply unit 10 includes a supply reel 10a and a tension adjustment unit 10b. The roll paper M is wound around the winding core of the supply reel 10a, and the roll paper M is fed out when the supply reel 10a rotates around the central axis of the winding core. The tension adjusting unit 10 b includes a roller that is urged to apply a predetermined tension to the roll paper M between the supply reel 10 a and the printing unit 11.

  The printing unit 11 includes a drum 11a, an introduction roller 11b, and a lead-out roller 11c. The drum 11a is formed in a columnar shape or an elliptical column shape, and rotates around the central axis X. The introduction roller 11b is a roller that introduces the roll paper M supplied from the supply unit 10 in the tangential direction of the side surface with respect to the drum 11a. The lead-out roller 11c is a roller that guides the roll paper M held on the side surface of the drum 11a in the tangential direction of the side surface of the drum 11a. When the drum 11a rotates counterclockwise on the paper surface, the roll paper M can be held on the side surface of the drum 11a, and the roll paper M can be conveyed from the supply unit 10 to the collection unit 12.

  The collection unit 12 includes a collection reel 12a and a tension adjustment unit 12b. The roll paper M is wound around the winding core of the collection reel 12a, and the collection paper 12a is wound around the central axis of the winding core by winding the collection reel 12a. The tension adjusting unit 12b includes a roller that is biased so as to apply a predetermined tension to the roll paper M between the collection reel 12a and the printing unit 11.

  The discharge head 13 is provided for each type of ink as a liquid. In this embodiment, the discharge head 13 is provided for each of C (cyan), M (magenta), Y (yellow), and K (black). Each of the discharge heads 13 has the same configuration as each other, and is provided so as to be rotationally symmetric with respect to the central axis X of the drum 11a. The discharge head 13 includes a nozzle surface 13a that faces the roll paper M held on the side surface of the drum 11a, and a plurality of nozzles are arranged in the surface of the nozzle surface 13a. Ink is ejected from a plurality of nozzles toward the roll paper M held on the side surface of the drum 11a. The ink discharge direction in each of the four discharge heads 13 is a direction toward the central axis X of the drum 11a.

  As shown in FIG. 1, the printer 1 includes a suction container 22, a collection container 23, and a suction fan 24 as a configuration of a mist collection device that collects ink mist. The suction container 22 is provided corresponding to each of the ejection heads 13 and is adjacent to the ejection head 13. The suction container 22 is adjacent to the vertical wall surface 13b (the wall surface orthogonal to the nozzle surface 13a) of the ejection head 13. That is, the suction container 22 is adjacent to the vertical wall surface 13b of the ejection head 13 (C, M, Y, K) from the counterclockwise direction on the paper surface. That is, the suction container 22 is adjacent to the vertical wall surface 13 b of the ejection head 13 from the downstream side in the transport direction of the roll paper M.

  When the suction fan 24 as a suction device is driven, the air in the collection container 23 is sucked. The plurality of suction containers 22 communicate with one collection container 23 via the lead-out part 22 c, and the air in each suction container 22 is collected in the collection container 23. A collection wall 23a (broken line) is formed inside the collection container 23, and the ink mist contained in the air of the collection container 23 collides with the collection wall 23a, whereby the ink mist is dropped. Make it. A storage part 23b is provided at the lower part of the collection container 23 in the vertical direction, and the ink droplets flow down to the storage part 23b and are stored in the storage part 23b. For example, the storage part 23b can be removed from the main body of the collection container 23, and by removing from the collection container 23, the storage part 23b can be replaced or cleaned.

  FIG. 2A is a schematic cross-sectional view of the suction container 22 cut in a direction orthogonal to the central axis X of the drum 11a. The suction container 22 includes a suction part 22a, a main body part 22b, and a lead-out part 22c. A suction port 22a1 is formed at the lower end of the suction portion 22a, and the suction portion 22a and the main body portion 22b communicate with each other at the upper end of the suction portion 22a. The suction part 22 a is adjacent to the vertical wall surface 13 b of the ejection head 13, and the suction port 22 a 1 is formed within a predetermined distance from the nozzle surface 13 a of the ejection head 13. That is, the distance between the suction port 22a1 and the nozzle surface 13a is a distance at which ink mist generated when ink droplets are ejected from the nozzles on the nozzle surface 13a can be sucked. The suction part 22a has a uniform shape in the height direction along the vertical wall surface 13b, and the shape of the flow path of the suction part 22a is a uniform rectangular shape from the upper end to the suction port 22a1 at the lower end. It has become.

  The main body portion 22b communicates with the suction portion 22a at the upper end of the suction portion 22a. The main body 22 b has an upper surface and a bottom surface parallel to the nozzle surface 13 a of the ejection head 13. The bottom surface of the main body portion 22b is orthogonal to the suction portion 22a. As shown in FIG. 1, the suction container 22 is adjacent to the surface of the vertical wall surface 13 b of the discharge head 13 that faces downward. Accordingly, the bottom surface of the main body portion 22b orthogonal to the vertical wall surface 13b is inclined so that the position becomes lower as the distance from the suction portion 22a adjacent to the vertical wall surface 13b increases. The main body portion 22b and the lead-out portion 22c communicate with each other at the end of the upper surface of the main body portion 22b opposite to the ejection head 13.

  As described above, the lead-out portion 22c communicates with the collection container 23, and the air in the collection container 23 is sucked when the suction fan 24 is driven. Therefore, when the suction fan 24 is driven, the air in the suction container 22 is sucked to the outside via the lead-out portion 22c, and the pressure of the air in the suction container 22 is reduced. Then, air containing mist in the vicinity of the nozzle is sucked into the suction container 22 through the suction port 22a1. Air containing mist flows upward from the suction port 22a1 in the suction part 22a. In FIG. 2A, the direction in which air is sucked is indicated by a thick arrow. The air containing mist flows in a direction away from the ejection head 13 in the main body 22b and reaches the outlet 22c.

  FIG. 2B is a diagram illustrating a wall surface (a part) of the suction portion 22a as viewed from the inside. As shown in the figure, a plurality of guide lines L are formed on the wall surface of the suction portion 22a. Each of the plurality of guide lines L is formed in a straight line in the vertical direction, and is arranged at a constant interval from each other.

  FIG. 2C is a bottom view showing the lower end surface (a part) of the suction portion 22a as viewed from below (as viewed from the arrow Y in FIG. 2A). As shown in the figure, each of the plurality of guide lines L is a groove having a semicircular cross section. That is, it has a shape that is depressed from the position of the surface of another region on the wall surface of the suction portion 22a. The guide wire L may be a wound formed by applying the tip of the needle to the inner wall surface of the planar suction portion 22a and moving the needle in the vertical direction. In addition, the guide line L may be a groove formed by etching using an etching mask that masks a region excluding the guide line L on the inner wall surface of the suction portion 22a.

  3A and 3B are schematic views showing a state in which ink mist adheres to the guide line L to form droplets. It is desirable that the mist of ink passes through the suction part 22a together with air and reaches the collection container 23 via the lead-out part 22c. However, it is inevitable that a part of the ink mist sucked by the suction part 22a collides with the wall surface of the suction part 22a and adheres to the wall surface of the suction part 22a. As shown in FIG. 3A, since the ink droplet tends to maintain a spherical shape due to surface tension, the ink droplet adhering to the guide line L that is recessed in a semicircular shape is on the other planar region. It comes in contact with the wall surface of the suction portion 22a with a larger contact area than the ink droplets attached to the ink. Therefore, it is easier to hold ink droplets on the guide line L than on other regions. When the ink mist further collides with the ink droplet adhering to the wall surface of the suction portion 22a, the ink mist is absorbed by the droplet and the droplet grows.

  Since it is easier to hold ink droplets on the guide line L than on other regions, the droplets are held on the guide line L in the process of ink droplet growth. . For example, when the ink droplet on the left side of FIG. 3A grows, a part of the droplet comes into contact with the guide line L and is drawn to the guide line L side. Further, when a droplet on the guide line L and a droplet on another region come into contact with each other, the droplet on the other region is drawn into the droplet on the guide line L. As described above, since the ink droplets can be held in a limited region on the guide line L, the aggregation of the ink droplets can be promoted. Then, due to the air resistance corresponding to the projected area of the ink droplets aggregated on the guide line L, the liquid droplets can be moved upward by an air flow directed from below to above. Since it is easier to hold ink on the guide line L than in other regions, ink droplets can be quickly guided upward along the guide line L formed in a vertical line shape. As a result, the ink mist stays in a very small volume in the entire area of the inner wall surface of the suction portion 22a, and prevents dripping onto the roll paper M when the suction fan 24 stops driving after the completion of printing, for example. it can.

  The ink droplet that has reached the upper end of the suction portion 22a along the guide line L enters the main body portion 22b and is held on the bottom surface of the main body portion 22b. As shown in FIG. 1, the bottom surface of the main body portion 22b of the suction container 22 provided corresponding to the ejection head 13 (Y, K) in a state where it is attached to the printer 1, the further away from the portion intersecting the suction portion 22a. The position is lowered. Accordingly, it is possible to guide the ink droplet that has reached the main body portion 22b on the bottom surface of the main body portion 22b so as to be separated from the suction portion 22a. Accordingly, it is possible to prevent the ink from flowing back from the main body portion 22b to the suction portion 22a and dropping the ink from the suction portion 22a onto the roll paper. On the other hand, the position of the bottom surface of the main body portion 22b of the suction container 22 provided corresponding to the ejection head 13 (C, M) increases as the distance from the portion intersecting the suction portion 22a increases. By providing a sponge or the like that absorbs ink, it is possible to prevent ink from flowing back from the main body portion 22b to the suction portion 22a and dropping from the suction portion 22a onto the roll paper.

(3) Modification:
4A is a bottom view showing a lower end surface (a part) of the suction portion 22a according to Modification 1 as viewed from below (as viewed in the direction of arrow Y in FIG. 2A). In the present embodiment, the guide line L is not formed as a groove, but is formed by applying a layer of a material with good ink wettability on the inner wall surface of the suction portion 22a. For example, when water-based ink is used and the suction part 22a is formed of a metal such as aluminum, materials having better ink wettability than the metal include epoxy resin, acrylic resin, diglycol alkyl carbonate resin, unsaturated polyester. Examples thereof include resins, polyurethane resins, polyimide resins, melamine resins, phenol resins, urea resins, and the like. Of course, the guide wire L only needs to have better wettability than other regions on the wall surface of the suction portion 22a, and the water repellent treatment may be performed on the other region on the wall surface of the suction portion 22a. Further, the guide wire L having good ink wettability may be formed by performing surface treatment such as polishing or etching on the wall surface of the suction portion 22a to roughen the surface.

  FIG. 4B is a diagram illustrating an inner wall surface (a part) of the suction portion 22a according to the second modification. As shown in the figure, the guide line L is formed in a branch line shape that branches downward. The guide line L may be a groove or may be formed by applying a material having good ink wettability. Thus, by making the guide line L into a branch line shape, the ink droplets can be aggregated as the ink droplets move upward. Further, the lower end of the guide wire L ends above the lower end of the suction portion 22a. Accordingly, it is possible to prevent the droplet of the guide line L from dropping from the guide line L as it is when the suction fan 24 stops driving.

  In the embodiment, the printer 1 ejects ink. However, a liquid other than ink may be ejected. Furthermore, the liquid may be discharged by pressurization due to mechanical changes of the piezo element, or may be discharged by pressurization due to generation of bubbles. Furthermore, the recording medium is not limited to printing paper, and may be a cloth or a resin film. Further, the recording medium is not limited to be held on the side surface of the drum, but may be held on a flat platen. Further, a plurality of ejection heads may not be provided, and a single or a plurality of suction containers may be provided for a single ejection head.

  DESCRIPTION OF SYMBOLS 1 ... Printer, 10 ... Supply part, 10a ... Supply reel, 10b ... Tension adjustment part, 11 ... Printing part, 11a ... Drum, 11b ... Introduction roller, 11c ... Outlet roller, 12 ... Collection part, 12a ... Collection reel, 12b DESCRIPTION OF SYMBOLS Tension adjustment part, 13 ... Discharge head, 13a ... Nozzle surface, 13b ... Vertical wall surface, 22 ... Suction container, 22a ... Suction part, 22a1 ... Suction port, 22b ... Main part, 22c ... Derivation part, 23 ... Collection container , 23a ... collection wall, 23b ... storage section, 24 ... suction fan, M ... roll paper, X ... central axis.

Claims (5)

A mist collecting device for collecting the mist of the liquid generated by discharging the liquid from a nozzle,
A suction container that forms a flow path of air sucked from the suction port, with a suction port formed within a predetermined distance from the nozzle as a lower end;
A suction device for generating an air flow upward from the suction port in the suction container;
A guide line that is formed in a vertical line shape on the wall surface that constitutes the flow path of the suction container, and that is more likely to hold the liquid droplets than other regions on the wall surface,
A mist collecting device comprising: The guide wire is a linear groove formed on the wall surface.
The mist collecting device according to claim 1. The guide line is a line that has been subjected to a surface treatment that makes the liquid wettability better than other regions on the wall surface.
The mist collecting device according to claim 1. The guide wire is formed in a branch line shape that branches downward on the wall surface.
The mist collection apparatus as described in any one of Claims 1-3. An ejection head for ejecting liquid from a nozzle;
A suction container that forms a flow path of air sucked from the suction port, with a suction port formed within a predetermined distance from the nozzle as a lower end;
A suction device for generating an air flow upward from the suction port in the suction container;
A guide line that is formed in a vertical line shape on the wall surface that constitutes the flow path of the suction container, and that is more likely to hold the liquid droplets than other regions on the wall surface,
A liquid ejection apparatus comprising:

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