JP2017007216A - Droplet discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a droplet discharge device which removes a liquid made into mist and existing between a droplet discharge part for discharging droplets as a liquid and a medium to which the droplet adheres or a supporting surface which supports the medium.SOLUTION: A droplet discharge device includes: a droplet discharge head 81 which discharges a liquid from a nozzle formed on a nozzle formation surface 81S as droplets; a carriage 83 which holds the droplet discharge head; a support part 20 having a support surface 21 which faces the nozzle formation surface and supports a medium M while facing the droplet discharge head; an ion generation part 87 which is provided at the carriage to generate ions; and a plate-like member 60 provided at the carriage and having a facing surface 63 facing the support surface which supports the medium. In the plate-like member, a hole part 62 is provided at a position that overlaps with at least one part of the ion generation part in a normal direction of the support surface.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a droplet discharge device including a droplet discharge unit that discharges liquid as droplets.

  Conventionally, as an example of a droplet discharge device, ink as an example of a liquid is dropped from a droplet discharge head as a droplet discharge unit onto a medium such as a sheet that is conveyed while being supported by a support surface of a support unit. An ink jet printer that prints characters and images by ejecting and attaching them as ink droplets) is known. In such printers, it is known that when ink is ejected as droplets from a droplet ejection head or when ink adheres to a medium, a mist of ink that floats in a charged state, that is, ink mist, is generated. It has been. When the generated ink mist adheres to a droplet discharge head or a medium, the print quality may be deteriorated.

  Therefore, as a method of preventing the generated ink mist from adhering to the medium, an ionizer that generates ions (atmospheric ions) is provided in a holding unit (carriage) that holds a droplet discharge head (recording head), and static electricity is generated. A configuration for functioning as a static elimination unit that eliminates static electricity has been proposed. That is, there is one that suppresses ink mist from adhering to the medium by removing static electricity generated in the medium using ions (ion gas) generated by an ionizer (see, for example, Patent Document 1).

JP 2015-24648 A

  By the way, in a recent ink jet printer, for example, a plurality of droplet discharge heads as droplet discharge units are held by a holding unit in a state where a plurality of droplet discharge heads are arranged along the width direction intersecting the paper conveyance direction. A configuration is employed in which printing is performed by ejecting ink from a droplet ejection head onto a medium. In such a printer, the portion where the droplet discharge head faces (opposite) the medium, or the portion where the droplet discharge head faces (opposite) the support portion has a wide range in the holding portion. It exists in the position away from the ionizer.

  For this reason, in a printer having a plurality of droplet discharge heads, when neutralizing static electricity generated in the medium using ions generated by an ionizer, the ink mist floating outside the holding unit is electrically neutralized. It is possible to remove the neutralized ink mist by, for example, an air flow. However, ink mist existing between the droplet discharge head and the medium or ink mist existing (floating) between the support surface of the support portion and the droplet discharge head at a position away from the ionizer is caused by the ionizer. It is difficult to neutralize using the generated ions.

  As a result, ink mist remaining between the droplet discharge head and the medium without being electrically neutralized, or remaining between the support surface of the support portion and the droplet discharge head without being electrically neutralized. Ink mist may float and adhere to the droplet discharge head or to the medium. For this reason, there is a problem that the print quality is deteriorated.

  Note that the above situation is not limited to an ink jet printer, but in a droplet ejection apparatus that ejects droplets from a droplet ejection unit capable of ejecting liquid as droplets to a medium facing the droplet ejection unit. It is common.

  The present invention has been made in view of the above circumstances. The purpose is a droplet discharge device capable of removing a mist-like liquid existing between a droplet discharge unit that discharges liquid as a droplet and a medium to which the droplet adheres or a support surface that supports the medium. Is to provide.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
A droplet discharge device that solves the above problems includes a droplet discharge unit that discharges liquid as droplets from a nozzle formed on a nozzle formation surface, a holding unit that holds the droplet discharge unit, and a nozzle formation surface. A support portion having a support surface that supports the medium in a state of facing the droplet discharge portion; an ion generation portion that is provided in the holding portion and generates ions; and is provided in the holding portion. A plate-like member having a facing surface that faces the support surface that supports the medium, and the plate-like member overlaps at least a part of the ion generating portion in a normal direction of the support surface. A hole is provided at the position.

  According to this configuration, the ions generated by the ion generating portion are caused to flow between the opposing surface of the plate-like member and the supporting surface of the supporting portion via the hole portion, thereby supporting the opposing surface of the plate-like member and the supporting portion. It becomes easy to neutralize the misted liquid existing between the surfaces. As a result, it is possible to remove the misted liquid by adhering it to the opposing surface of the plate-like member between the droplet adhering medium or the support surface that supports the medium and the droplet discharge section.

In the droplet discharge device, it is preferable that the plate-like member has the facing surface at a position that does not overlap the nozzle forming surface in the normal direction of the support surface of the support portion.
According to this configuration, the misted liquid is neutralized at a position away from the nozzle formation surface of the droplet discharge unit between the opposed surface of the plate-like member and the support surface of the support unit, and is attached to the opposed surface. Therefore, it can suppress that the mist-ized liquid adheres to the nozzle formation surface of a droplet discharge part.

In the droplet discharge device, the plate-like member is preferably a conductive member.
According to this configuration, ions that flow between the opposing surface of the plate-like member and the support surface of the support portion are quickly diffused over the entire opposing surface in the plate-like member having conductivity such as metal, so that the support portion The misted liquid remaining between the supporting surface and the droplet discharge portion can be neutralized by the diffused ions. Further, the neutralized mist-like liquid can be removed by adhering to the opposing surface of the plate-like member.

In the liquid droplet ejection apparatus, it is preferable that the facing surface is an uneven surface that is partially different in distance from the support surface.
According to this configuration, many ions can flow between the opposing surface of the plate-like member and the supporting surface of the support portion along the opposing surface whose surface area is increased by the uneven shape. As a result, the misted liquid remaining between the support surface of the support portion is neutralized with a high probability by the facing surface having a large surface area of the plate-like member, and the neutralized liquid is adhered to the facing surface. be able to.

  The plate-like member has an extending portion extending from the holding portion to the outside that does not overlap with the holding portion in a direction along the support surface and in a normal direction of the support surface, and the hole portion is It is preferable that the extension portion is provided.

According to this configuration, it is easy to allow ions to flow between the opposing surface and the support surface from the outside of the holding portion.
In the liquid droplet ejection apparatus, the holding unit is movable relative to the support surface, and the ion generation unit moves in a moving direction of the holding unit when the holding unit moves. It is preferable to generate ions at a position on the side.

According to this configuration, ions generated on the movement destination side of the holding unit can be caused to flow between the opposing surface of the plate-like member and the support surface of the support unit as the holding unit moves.
In the liquid droplet ejection apparatus, it is preferable that the ion generator generates negative ions.

  According to this configuration, when the misted liquid has a high probability of being positively charged, the misted liquid can be effectively neutralized.

1 is a side sectional view showing an embodiment of a droplet discharge device. The top view which looked at the droplet discharge unit with which a droplet discharge device is provided from the perpendicular upper direction. The front view which looked at the droplet discharge unit from the conveyance direction of the medium. The bottom view which looked at the droplet discharge unit from the perpendicular lower part. The perspective view which looked at the droplet discharge unit from diagonally downward at the time of ion generation. The front view which looked at the droplet discharge unit from the conveyance direction of the medium at the time of ion generation. The front view which looked at the droplet discharge unit from the conveyance direction of the medium at the time of ion generation. The perspective view which shows the droplet discharge unit provided with the plate-shaped member of the uneven | corrugated surface of a bellows shape. The perspective view which shows the droplet discharge unit provided with the flat metal plate as a plate-shaped member. The front view which shows the droplet discharge unit provided with the ion generation part on the moving direction side.

  Hereinafter, an embodiment of a droplet discharge device will be described with reference to the drawings. The droplet discharge device of this embodiment is an ink jet printer (large format printer) that prints characters and images on a medium by discharging liquid as droplets onto a long medium.

  As shown in FIG. 1, the droplet discharge device 10 of the present embodiment includes a support unit 20 that supports the medium M on the support surface 21, a transport unit 30 that transports the medium M, and the feeding and winding of the medium M. A housing 11 serving as an apparatus main body includes a feeding unit 40 and a winding unit 50 that perform and a droplet discharge unit 80 that discharges droplets onto a medium M. Moreover, the ventilation part 70 which generate | occur | produces an air current from the exterior to the inside of the housing | casing 11 by ventilating is provided.

  Here, in order to facilitate the following description, the direction along the support surface 21 that is perpendicular to the moving direction of the medium M when the transport unit 30 transports the feed unit 40 to the take-up unit 50 has a width. Also referred to as direction X (see FIG. 2). Of the moving direction of the medium M, the direction along the support surface 21 is also referred to as the transport direction Y, the upstream side in the transport direction Y is simply referred to as “upstream side”, and the downstream side in the transport direction Y is simply “downstream”. Also called. In the present embodiment, the transport direction Y of the medium M is a substantially horizontal direction, and the normal direction of the support surface 21 intersecting (orthogonal) with both the width direction X and the transport direction Y is a direction along the vertical direction Z. Has been. Therefore, the normal direction of the support surface 21 is also referred to as the vertical direction Z.

  The support portion 20 has a rectangular plate shape whose longitudinal direction is the width direction X (see FIG. 2). Further, in the support unit 20, the surface on the antigravity direction (upward) side in the vertical direction Z on the droplet discharge unit 80 side is a support surface 21 that supports the medium M from the gravity direction (downward) in the vertical direction Z. Yes. In addition, in the support part 20, when a recessed part is formed, for example by forming the suction hole which adsorb | sucks the medium M in order to suppress the lift from the support surface 21 of the medium M, the part except this recessed part is formed. The surface that supports the medium M is the support surface 21.

  The transport unit 30 includes a first transport roller pair 31 disposed on the upstream side of the support unit 20 and a second transport roller pair 32 disposed on the downstream side of the support unit 20. The conveyance roller pairs 31 and 32 include a drive roller that applies a conveyance force to the medium M, and a driven roller that is driven to rotate by contacting the medium M to be conveyed. Then, the transport unit 30 transports the medium M toward the downstream side by driving the drive roller in a state where the medium M is sandwiched between the transport roller pairs 31 and 32.

  The transport unit 30 includes a first guide unit 33 disposed on the upstream side of the first transport roller pair 31, and a second guide unit 34 disposed on the downstream side of the second transport roller pair 32. It is equipped with. The first guide portion 33 forms a part of the feeding port 12 that passes when the medium M is transported into the housing 11. Further, the second guide part 34 forms a part of the discharge port 13 through which the medium M passes when transported to the outside of the housing 11.

  The first guide unit 33 guides the medium M fed from the feeding unit 40 to the first transport roller pair 31 while supporting the medium M from below in the vertical direction Z. In addition, the second guide unit 34 guides the medium M conveyed from the second conveyance roller pair 32 to the winding unit 50 while supporting the medium M from below in the vertical direction Z.

  The feeding unit 40 includes a feeding shaft 41 around which a long medium M is wound. Then, the feeding unit 40 feeds the medium M to the downstream side by rotating the feeding shaft 41 counterclockwise in FIG. The winding unit 50 includes a winding shaft 51 that winds the long medium M. The winding unit 50 winds the medium M by rotating the winding shaft 51 counterclockwise in FIG. The feeding unit 40 may wind the medium M, while the winding unit 50 may feed the medium M to the upstream side.

  The air blowing unit 70 includes a fan 71 that generates an air flow and a duct 72 through which gas flows. The duct 72 is provided with an external communication port 73 that communicates with the outside of the housing 11 and an internal communication port 74 that communicates with the inside of the housing 11. The blower 70 drives the fan 71 to blow out gas (air) from the internal communication port 74 of the duct 72. The internal communication port 74 is configured such that the gas blown out from the internal communication port 74 blows to the support portion 20 from above in the vertical direction Z as shown by the two-dot chain line arrow F in FIG. Is formed to go downstream along the support surface 21.

  As shown in FIGS. 1 and 2, the droplet discharge unit 80 includes a droplet discharge head 81 as a droplet discharge unit that discharges droplets, and a carriage 83 as a holding unit that holds the droplet discharge head 81. It has. The liquid droplet ejection head 81 has a nozzle formation surface 81S, and a liquid supplied from a plurality of nozzles N forming a nozzle row formed on the nozzle formation surface 81S to the liquid droplet ejection head 81 from a liquid storage unit (not shown). Are discharged as droplets.

  In the present embodiment, four droplet discharge heads 81 are arranged in parallel in the width direction X and are provided as one head unit 82, and each droplet discharge head 81 has a different color type (for example, color ink). Discharge as droplets. Two head units 82 are provided at an interval in the width direction X, and these two head units 82 are held at positions shifted from each other in the transport direction Y.

  The carriage 83 is movable relative to the support surface 21 of the support unit 20. That is, the carriage 83 reciprocates in the width direction X while being supported by the guide shaft 84 by driving a motor (not shown). As the carriage 83 moves, the droplet discharge unit 80 reciprocates in the width direction X. Then, the droplets from the droplet discharge heads 81 of the two head units 82 held by the carriage 83 included in the droplet discharge unit 80 that reciprocates in the width direction X toward the medium M supported on the support surface 21. Is discharged. At this time, the support surface 21 is a surface facing the nozzle forming surface 81 </ b> S and supports the medium M in a state facing the droplet discharge unit 80.

  Further, in the present embodiment, in the droplet discharge unit 80, ion generators 87 and 88 that generate ions are provided in the carriage 83. Specifically, an ion generator 86 having ion generators 87 and 88 is provided attached to one side end in the width direction X (movement direction) with respect to the carriage 83. The ion generator 86 can employ an ionizer that generates ions (atmospheric ions) by, for example, electron emission by discharge. The ionizer can generate either one of positive ions and negative ions by DC discharge or both ions by AC discharge.

  As shown in FIGS. 2, 3, and 4, in the droplet discharge unit 80, the carriage 83 extends from the carriage 83 in the direction along the support surface 21 to the bottom on the gravity direction side in the vertical direction Z. A plate-like member 60 having an extending portion 61 is attached and provided. In the present embodiment, the plate-like member 60 is formed by molding a non-conductive or hardly conductive resin material (for example, polyacetal resin), and the extending portion 61 extends from the lower portion (bottom portion) of the carriage 83. In the normal direction of the support surface 21, it is provided so as to extend to the outside that does not overlap the carriage 83, that is, both the outside in the width direction X. Further, the shape of the extending portion 61 of the plate-like member 60 is such that the width, which is the length in the transport direction Y, is narrower from the carriage 83 toward the outside as viewed from the normal direction of the support surface 21 (here, the vertical direction Z). This is a substantially triangular shape.

  In the present embodiment, the ion generators 87 and 88 are provided at positions facing the support surface 21 in the normal direction of the support surface 21 and at positions separated from each other in the transport direction Y. Among these, the ion generation part 87 on the upstream side in the transport direction Y is connected to the extension part 61 extending outside the carriage 83 between the lower side on the support surface 21 side of the extension part 61 and the upper side on the opposite side. It is provided so that it may overlap in the normal direction of the support surface 21 with respect to the hole 62 provided as a through-hole opened on both sides. In other words, the extending part 61 of the plate-like member 60 is provided with a hole 62 at a position overlapping the ion generating part 87 in the normal direction of the support surface 21.

  As shown in FIG. 4, the hole 62 is provided at a position where at least a part thereof overlaps with the ion generator 87 in the normal direction of the support surface 21. Incidentally, in this embodiment, the hole 62 is divided into a plurality of (here, seven) holes by ribs provided to suppress the deformation, as indicated by the shaded area in FIG. Of the plurality of divided holes, two holes (reference numerals 62 a and 62 b) are provided at positions that overlap at least a part of the ion generating portion 87 in the normal direction of the support surface 21. More specifically, in the present embodiment, these two holes (reference numerals 62 a and 62 b) have openings (two openings) on the ion generation part 87 side (upper side) in the normal direction of the support surface 21. It is provided so as to overlap the entire ion generator 87.

  As shown in FIGS. 3, 4, and 5, the plate-like member 60 attached to the bottom of the carriage 83 does not overlap with the nozzle forming surface 81 </ b> S in the normal direction of the support surface 21 of the support unit 20. Has a facing surface 63 that faces the support surface 21. In the present embodiment, the opposing surface 63 corresponds to substantially the entire lower surface of the plate-like member 60 on the gravity direction side, and around the nozzle formation surface 81S of the droplet discharge head 81, a part of the carriage 83. It is formed so as to surround one part 83a. Further, the facing surface 63 is an uneven surface having a partially different distance from the support surface 21, for example, a plurality of surfaces (for example, surfaces indicated by reference numerals 63a, 63b, and 63c) having a different distance from the support surface 21. The uneven surface is an uneven surface.

  In the droplet discharge device 10 of the present embodiment configured as described above, floating liquid (hereinafter also referred to as “liquid mist”) generated in a charged state by the discharge of the liquid from the droplet discharge head 81 is generated. To do. Of the generated liquid mist, the liquid mist that has jumped from the inside of the carriage 83 (that is, in the region immediately below the carriage 83) to the outside of the carriage 83 (that is, outside the region immediately below the carriage 83) is ion generators 87 and 88. It is easily neutralized electrically by the ions generated in The neutralized liquid mist is the support surface 21 after the gas (air) blown from the internal communication port 74 blown by the blower 70 blows against the support surface 21 or the medium M on the support surface 21. When flowing along the medium M, it is removed by the flowing gas.

  Further, as an operation of the present embodiment, the liquid mist staying inside the carriage 83 is electrically neutralized in the droplet discharge device 10. This operation will be described with reference to FIGS. 6 and 7, for ease of explanation, a part of the plate-like member 60 is broken, and the plate-like member 60 and the droplet discharge head 81 are shown in cross section at the broken portion. Yes. Further, the gap between the nozzle forming surface 81S of the droplet discharge head 81 and the support surface 21 (medium M) of the support unit 20 is illustrated larger than the actual size.

  As shown in FIG. 6, the liquid mist 90 generated by the discharge of the liquid from the droplet discharge head 81 stays (exists) in the portion inside the carriage 83. That is, in the present embodiment, the inner part of the carriage 83 includes the facing surface 63 of the plate-like member 60 attached to the bottom of the carriage 83, the nozzle forming surface 81S of the droplet discharge head 81, and the facing surface 63. The portion is covered with a portion 83a of the carriage 83 sandwiched between the nozzle forming surface 81S. The liquid mist 90 is formed between the opposed surface 63 of the plate-like member 60 and the medium M on the support surface 21, between the nozzle forming surface 81 </ b> S and the medium M on the support surface 21, and a part of the carriage 83. It stays in a floating state between 83a and the medium M on the support surface 21.

  By the way, in the present embodiment, it is assumed that the liquid mist 90 present in the portion inside the carriage 83 is positively charged. One reason for this is the Leonard effect. That is, the droplet is positively charged and the gas is negatively charged by the contact potential existing between the falling (discharging) droplet (liquid) and the gas (atmosphere). Then, the negative electricity charged in the gas is diffused from there to the surrounding atmosphere by collision with the medium M when the droplet reaches the medium M. On the other hand, the positive electricity of the droplets remains in the minute droplets (liquid mist 90) generated at the time of collision, in addition to the amount flowing in the colliding medium M. Therefore, between the facing surface 63 of the plate-like member 60 and the medium M on the support surface 21, between the nozzle forming surface 81S and the medium M on the support surface 21, a portion 83a of the carriage 83 and the support surface. It is considered that there is a high probability that a positively charged liquid mist 90 is generated between the medium 21 on the medium 21 and the medium M.

  Therefore, as shown in FIG. 6, in this embodiment, negative ions 91 are generated in the ion generators 87 and 88. And the ion generation parts 87 and 88 discharge | release so that the produced | generated negative ion 91 may be irradiated or sprayed toward the downward direction of the vertical direction Z. FIG. As a result, the ions 91 released from the ion generating portion 87 are supported by the opposing surface 63 of the plate-like member 60 via (pass through) the hole 62 provided in the extending portion 61 of the plate-like member 60. It easily flows between the medium M on the surface 21. Although not shown here, the ions 91 emitted from the ion generating portion 88 are opposed to the opposing surface of the plate member 60 from the vicinity of the hypotenuse portion of the substantially triangular extension portion 61 of the plate member 60. 63 and the medium M on the support surface 21.

  As shown in FIG. 7, negative ions 91 that flow between the facing surface 63 of the plate-like member 60 and the medium M on the support surface 21 are positively charged liquid mist existing inside the carriage 83. 90 is electrically neutralized. At this time, since the inflowing ions 91 enter and move along the uneven shape of the facing surface 63, the neutralized liquid mist 90 adheres to the facing surface 63 that is made uneven so that the surface area thereof becomes large. . Further, the facing surface 63 is provided so as to surround the nozzle forming surface 81S at a position away from the nozzle forming surface 81S without overlapping the nozzle forming surface 81S in the normal direction of the support surface 21. Therefore, the positively charged liquid mist 90 between the nozzle forming surface 81S and the medium M moves from the nozzle forming surface 81S side to the facing surface 63 side to be neutralized, and the nozzle forming surface 81S It adheres to the opposing surface 63 without adhering.

  Further, in the present embodiment, the ion generators 87 and 88 are provided on the carriage 83 that moves relative to the support surface 21 at a position on the movement destination side in the movement direction of the carriage 83. That is, when the carriage 83 moves with the position where the ion generators 87 and 88 are provided in the width direction X as indicated by a solid solid arrow in FIG. 88 generates negative ions 91.

  As a result, the ions 91 flowing between the facing surface 63 of the plate-like member 60 and the medium M on the support surface 21 are between the facing surface 63 of the plate-like member 60 and the medium M on the support surface 21. As shown by white broken arrows in FIG. 7, it moves (relatively moves) toward the opposite side far from the position where the ion generating portions 87 and 88 are provided. By the moving negative ions 91, the positively charged liquid mist 90 existing inside the carriage 83 is electrically neutralized.

  In the present embodiment, for example, when the length of the medium M in the width direction X is short, the opposed surface 63 of the plate-like member 60, the nozzle forming surface 81S, the part 83a of the carriage 83, and the medium M are not present. A positively charged liquid mist 90 may stay between the support surface 21 and the support surface 21. In such a case, the negative ions 91 flow between the facing surface 63 of the plate-like member 60 and the support surface 21, and electrically discharge the positively charged liquid mist 90 existing inside the carriage 83. Neutralize.

  Further, in the present embodiment, the plate-like member 60 attached to the carriage 83 allows the droplets ejected from the droplet ejection head 81 to adhere to the medium M with high accuracy when the carriage 83 moves in the width direction X ( The air flow between the nozzle forming surface 81S and the medium M on the support surface 21 may function as a windbreak plate that rectifies the air flow.

According to the embodiment described above, the following effects can be obtained.
(1) The ions 91 generated by the ion generator 87 are caused to flow between the facing surface 63 of the plate-like member 60 and the support surface 21 of the support portion 20 through the hole 62 to face the face of the plate-like member 60. It becomes easy to neutralize the liquid mist 90 that exists (stays) in a floating state between 63 and the support surface 21 of the support portion 20. As a result, the liquid mist 90 is attached to the opposing surface 63 of the plate-like member 60 and removed between the medium M to which the droplets adhere or the support surface 21 that supports the medium M and the droplet discharge head 81. it can.

  (2) Between the opposing surface 63 of the plate-like member 60 and the support surface 21 of the support portion 20, the liquid mist 90 is neutralized at a position away from the nozzle forming surface 81 </ b> S of the droplet discharge head 81 to oppose the opposing surface 63. Therefore, the liquid mist 90 can be prevented from adhering to the nozzle forming surface 81S of the droplet discharge head 81.

  (3) A large number of ions 91 can flow between the facing surface 63 of the plate-like member 60 and the supporting surface 21 of the support portion 20 along the facing surface 63 whose surface area is increased by the uneven shape. As a result, the liquid mist 90 remaining between the support surface 21 and the support surface 21 of the support portion 20 is neutralized with a high probability by the facing surface 63 in which the surface area of the plate-like member 60 is increased. It can be adhered to the facing surface 63.

  (4) It becomes easy to allow ions 91 to flow between the facing surface 63 and the support surface 21 from the outside of the carriage 83 through the hole 62 provided in the extending portion 61. In addition, the extending portion 61 provided outside the carriage 83 prevents the air blown by the blower 70 from hitting the support surface 21 near the carriage 83, so that the ions 91 that flow into the vicinity of the carriage 83 are retained. Can do.

  (5) The ions 91 generated on the movement destination side of the carriage 83 are caused by the movement of the carriage 83 between the facing surface 63 of the plate-like member 60 and the support surface 21 of the support portion 20 or the medium M on the support surface 21. Can flow in between.

(6) When the probability that the liquid mist 90 is positively charged is high, the liquid mist 90 can be effectively neutralized effectively by the generated negative ions 91.
In addition, you may change the said embodiment as shown below.

In the above embodiment, the facing surface 63 may be a surface other than the concavo-convex surface composed of a plurality of surfaces having different distances from the support surface 21. This modification will be described with reference to the drawings.
As shown in FIG. 8, the distance between the facing surface 63 and the support surface 21 (not shown) is constant in the movement direction (width direction X) of the carriage 83, and the support surface 21 is in the transport direction Y. The uneven | corrugated surface from which the distance between changes periodically may be sufficient. That is, the opposing surface 63 of this modified example has irregularities that exhibit a so-called bellows shape in which a plurality of mountain-shaped portions 64 and valley-shaped portions 65 extending along the width direction X are alternately formed in the transport direction Y. It is considered as a surface.

  The concavity and convexity surface 63 having an accordion shape is formed with a hole 62 formed as one hole in the extending portion 61, and a part of the head unit 82 (nozzle formation surface 81 </ b> S) and the carriage 83. It is a surface surrounding 83a. The mountain-shaped portion 64 of the facing surface 63 is formed farther from the support surface 21 (not shown) than the nozzle forming surface 81S. Moreover, although the hole part 62 is made into one hole, you may form with the some hole which pinched | interposed the rib like the said embodiment.

  As described above, the facing surface 63 is an uneven surface having a bellows shape, so that the surface area of the facing surface 63 is increased, and ions 91 (not shown) flowing from the hole 62 have a width in the valley-shaped portion 65. It becomes easy to move along the direction X toward the extending portion 61 on the side opposite to the hole portion 62. As a result, the liquid mist 90 staying between the opposing surface 63 and the support surface 21 is neutralized over the entire area of the opposing surface 63, and the neutralized liquid mist 90 is attached to the opposing surface 63. it can.

  In the above embodiment, the facing surface 63 of the plate-like member 60 is not necessarily an uneven surface, and may be a flat surface, for example. When the facing surface 63 is a flat surface, the plate-like member 60 is not necessarily a non-conductive or hardly conductive resin member but may be a conductive member. This modification will be described with reference to the drawings.

  As shown in FIG. 9, in this modification, the plate member 60 is a flat plate member (for example, a stainless plate or an aluminum plate) made of a conductive metal material. Of course, even if it is a resin material, if it is a conductive plastic (for example, polyacetylene) or a composite conductive plastic, it can be adopted as the material of the plate-like member 60.

  The plate-like member 60 of the present modification has a flat facing surface 63, and the distance (gap) from the support surface 21 (not shown) is substantially constant over the entire facing surface 63. The facing surface 63 which is a flat surface is formed with a hole 62 in the extending portion 61, and the head unit 82 (nozzle forming surface 81 </ b> S) and a portion 83 a of the carriage 83 overlap in the normal direction of the support surface 21. The surface is surrounded without any problems. In the present modification, the hole 62 is a single hole, but may be formed of a plurality of holes with ribs interposed therebetween as in the above embodiment.

  As described above, since the conductive plate-like member 60 having the opposing surface 63 as a flat surface easily flows an electric current, electrons easily move along the surface of the member, that is, the opposing surface 63. As a result, as indicated by solid line arrows in FIG. 9, negative ions 91 having electrons generated in the ion generating portions 87 and 88 are formed in the extending portion 61 on the opposite side of the hole 62 along the facing surface 63. In order to move quickly toward the surface, many ions 91 that have flowed from the hole 62 diffuse into the facing surface 63.

According to the modification shown in FIG. 9, the following effect can be obtained in place of the effect (3) of the above embodiment.
(7) The ions 91 flowing between the facing surface 63 of the plate-like member 60 and the support surface 21 of the support portion 20 quickly diffuse over the entire surface of the facing surface 63 in the plate-like member 60 having conductivity such as metal. Thus, the liquid mist 90 remaining between the support surface 21 of the support portion 20 and the droplet discharge head 81 can be neutralized by the diffused ions 91. Further, the neutralized liquid mist 90 can be attached to the opposing surface 63 of the plate-like member 60 and removed.

  -Alternatively, in the above embodiment, the plate-like member 60 in which the opposing surface 63 is an uneven surface may be used as a conductive member. Moreover, also in the modified example shown in FIG. 8, the plate-like member 60 in which the opposing surface 63 is an uneven surface having a bellows shape may be used as a conductive member. By doing in this way, both the effect (3) of the said embodiment and the effect (7) of the said modification are acquired.

  In the above-described embodiment, the ion generators 87 and 88 are not necessarily provided at one side end in the width direction X of the carriage 83 with respect to the carriage 83. For example, when the droplets are ejected from the droplet ejection head 81 when the carriage 83 reciprocates along the width direction X, the ion generation units 87 and 88 are relative to the carriage 83 in the width direction X of the carriage 83. It is preferable that it is provided at both side ends in. This modification will be described with reference to the drawings.

  As shown in FIG. 10, in this modification, in the carriage 83 that moves relative to the support surface 21, ions are generated at a position on one side in the movement direction (width direction X) of the carriage 83. An ion generator 86A is provided at a position where the device 86 is on the other destination side.

  That is, when the carriage 83 moves to the side where the ion generator 86 is provided in the width direction X, as shown by a solid solid arrow in FIG. 10, ions 91 are generated from the ion generator 87 of the ion generator 86. Then, ions 91 are caused to flow between the facing surface 63 and the medium M on the support surface 21 through the hole 62 provided in the extending portion 61. Alternatively, when the carriage 83 moves to the side where the ion generator 86A is provided in the width direction X, as shown by a white two-dot chain line arrow in FIG. 10, ions 91 from the ion generator 87A of the ion generator 86A. And ions 91 are caused to flow between the facing surface 63 and the medium M on the support surface 21 through a hole 62A provided in the extending portion 61.

  As a result, when the carriage 83 moves in both directions in the width direction X (reciprocating), the plate member 60 on the opposing surface 63 and the support surface 21 can be moved in any of the two directions. Ions 91 can easily flow into the medium M. Accordingly, the positively charged liquid mist 90 existing inside the carriage 83 can be electrically neutralized more quickly. Of course, in the modification shown in FIG. 10, when ions are generated from the ion generator 87 or the ion generator 87A, ions may be generated from the ion generator 88 or the ion generator 88A.

  In the above embodiment, the plate-like member 60 does not necessarily have the facing surface 63 at a position that does not necessarily overlap with the nozzle forming surface 81S in the normal direction (vertical direction Z) of the support surface 21 of the support portion 20. Also good. For example, the facing surface 63 may be formed so that at least a part thereof overlaps the nozzle forming surface 81S in the normal direction. Of course, in this case, the facing surface 63 is formed in a shape that does not hinder the discharge of droplets from the nozzle N.

  In the above embodiment, the ion generators 87 and 88 do not necessarily generate the negative ions 91. For example, when the liquid mist 90 existing inside the carriage 83 is both positively charged and negatively charged, the ion generators 87 and 88 are negative. It is preferable to generate both positive ions 91. For example, one of the ion generator 87 and the ion generator 88 may generate negative ions 91 and the other generate positive ions 91. In addition, when the liquid mist 90 present in the inner portion of the carriage 83 is negatively charged, the ion generators 87 and 88 preferably generate positive ions 91.

  In the above-described embodiment, the shape of the extending portion 61 of the plate-like member 60 is not necessarily the width that decreases from the carriage 83 toward the outside as viewed from the normal direction of the support surface 21 (here, the vertical direction Z). It does not have to be triangular. For example, it may be a rectangular shape having the same width and extending in the width direction X. In this case, it is preferable that a hole that overlaps in the normal direction is provided in the extending portion 61 with respect to the ion generating portion 88.

  In the above embodiment, the ion generator 86 is provided with the two ion generators 87, 88, but only the ion generator 87 on the upstream side in the transport direction Y may be provided in the ion generator 86. Alternatively, three or more ion generation units including at least the ion generation unit 87 may be provided.

  In the above embodiment, the extending portion 61 of the plate-like member 60 does not necessarily extend outward from the carriage 83 in the width direction X. For example, the extending portion 61 may extend outward from the carriage 83 in the transport direction Y. In this case, it is preferable that at least one of the two ion generation portions 87 and 88 is provided at a position where the hole portion 62 provided in the extending portion 61 and the support surface 21 overlap in the normal direction.

  In the above embodiment, the plate-like member 60 may not have an extending portion that extends from the holding portion to the outside that does not overlap in the normal direction of the support surface 21. In such a case, although description by illustration is omitted here, the hole 62 is formed in the plate-like member 60 inside the carriage 83, and overlaps with the normal direction with respect to the formed hole 62. In addition, it is preferable that an ion generator 87 is provided inside the carriage 83 so as to communicate with the hole 62.

  In the above embodiment, the head unit 82 does not necessarily have to be provided with four droplet discharge heads 81 arranged in parallel in the width direction X. For example, three or less droplet discharge heads 81 may be provided, or five or more droplet discharge heads 81 may be provided. Further, one head unit 82 may be held and provided in the carriage 83, or three or more head units 82 may be held and provided.

  In the above embodiment, the air blowing unit 70 may be formed so that most of the gas blown to the support unit 20 from above in the vertical direction Z is directed upstream along the support surface 21. Or the ventilation part 70 does not necessarily need to be provided. The air blowing unit 70 is not a blower fan that generates an air flow from the outside of the housing 11 to the inside, but a suction that generates an air flow from the inside of the housing 11 to the outside and discharges the liquid mist 90 to the outside of the housing 11. It may function as a fan.

In the above embodiment, the material of the medium M may be a resin, a metal, a fabric, or paper.
In the above embodiment, the droplet discharge device 10 is not limited to a printer that discharges droplets to the long medium M wound around the feeding shaft 41, but has a predetermined length in the transport direction Y. An ink jet printer that prints characters and images by discharging droplets onto the leaf medium M may be used.

  In such a printer, even when the medium M does not exist on the support surface 21, the positively charged liquid mist 90 may stay. In this case, the negative ions 91 flow between the opposing surface 63 of the plate member 60 and the support surface 21 to electrically neutralize the positively charged liquid mist 90 existing inside the carriage 83. can do.

  The droplet discharge device 10 may be a printer (for example, a line printer or a page printer) in which the carriage 83 does not move relative to the support surface 21.

  DESCRIPTION OF SYMBOLS 10 ... Droplet discharge device, 20 ... Support part, 21 ... Support surface, 60 ... Plate member, 61 ... Extension part, 62, 62A ... Hole, 63 ... Opposite surface, 81 ... Droplet discharge head (droplet An example of a discharge part), 81S ... Nozzle formation surface, 83 ... A carriage (an example of a holding part), 87, 87A, 88, 88A ... Ion generation part, 91 ... Ion, M ... Medium, N ... Nozzle, X ... Width direction (Moving direction of holding part), Y: transport direction, Z: vertical direction (normal direction of support surface).

Claims (7)

A droplet discharge unit that discharges liquid as droplets from a nozzle formed on the nozzle formation surface;
A holding unit for holding the droplet discharge unit;
A support portion having a support surface that is a surface facing the nozzle forming surface and supports the medium in a state of facing the droplet discharge portion;
An ion generation unit that is provided in the holding unit and generates ions;
A plate-like member provided on the holding portion and having a facing surface facing the supporting surface for supporting the medium;
With
The droplet discharge device, wherein the plate-like member is provided with a hole at a position overlapping with at least a part of the ion generating portion in the normal direction of the support surface.   2. The droplet discharge device according to claim 1, wherein the plate-like member has the facing surface at a position that does not overlap the nozzle forming surface in a normal direction of the support surface of the support portion.   The droplet discharging apparatus according to claim 1, wherein the plate-like member is a member having conductivity.   4. The droplet discharge device according to claim 1, wherein the facing surface is an uneven surface having a partially different distance from the support surface. 5. The plate-like member has an extending portion extending from the holding portion to the outside that does not overlap the holding portion in a direction along the support surface and in a normal direction of the support surface;
The droplet discharge device according to claim 1, wherein the hole portion is provided in the extending portion. The holding portion is movable relative to the support surface;
6. The ion generation unit according to claim 1, wherein the ion generation unit generates ions at a position on a movement destination side in a movement direction of the holding unit when the holding unit moves. Droplet discharge device.   The liquid droplet ejection apparatus according to claim 1, wherein the ion generation unit generates negative ions.