JP5032216B2 - Inkjet recording device, absorbent sheet - Google Patents

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to an absorption sheet for preventing ink from adhering to a platen, and an ink jet recording apparatus in which dirt due to ink hardly adheres to a platen.

  In an inkjet printer, ink can be ejected from an inkjet head and characters and images can be recorded on a wide variety of print media. For example, there is one that records images and characters on a sheet-like printing medium such as vinyl chloride or tarpaulin using a solvent ink as a paint. In addition, these print media are sometimes used outdoors, and tarpaulins are used for building cover sheets and signboards. Further, there are mesh-like objects in the print media. The ink jet printer can also print characters and images by ejecting ink onto a mesh-like medium. However, when a mesh-like print medium is used, there is a problem that ink passes through the print medium and stains the platen, and the dirt also stains the back surface of the print medium.

  Conventionally, polyester non-woven fabric is used as a slip sheet, and this slip sheet is placed between the back side of the printing media and the platen, transported with the printing media, and the penetrating ink is absorbed by the slip sheet. It was avoiding by letting.

Japanese Patent Laid-Open No. 2002-337405 discloses an ink jet printer in which one or more portions of a printing ink landing surface of a platen are cut out in a concave shape, and an ink absorbing member made of an ink absorbing material is attached to the concave portion. It is disclosed. In this ink jet printer, the platen is detachable and the ink absorbing material is exchangeable.
JP 2002-337405 A

  In the conventional method, when the interleaving paper is transported along with the printing medium, the same amount of interleaving paper as the printing media is required, and the printing media becomes heavy and large. It is necessary to transport the print media and the interleaving paper in an overlapping manner, or to separate the print media and the interleaving paper after printing, and the mounting and handling properties of the print media to the ink jet printer are poor.

  Further, when a printer is used in which a concave portion is provided on the platen and an ink adsorbing member is adhered thereto, the platen becomes a dedicated platen using an ink absorbing material. Some print media tend to bend and wrinkle on the printing surface, and wrinkles and bends in the concave portion, making it difficult to print. In addition, when replacing the platen, the platen with the concave portion must be removed and a flat surface platen must be attached, resulting in poor handling of the printer. Further, the ink adhering to the ink absorbing material is not immediately dried, and the handling property is inconvenient and inconvenient such as a problem that the ink adhering to the media or the operator when the printing medium is replaced or the ink absorbing material is replaced.

As means for solving the above-mentioned problems, a first aspect of the ink jet recording apparatus of the present invention comprises a transport means for transporting a print medium and an ink jet head for ejecting ink to the print medium transported by the transport means. In the inkjet recording apparatus, a platen having a through-wall forming a through-hole, a suction device that sucks and exhausts air from the through-hole by a fan, and an absorbent sheet disposed in a portion facing the inkjet head on the platen When printing on the medium, the portion of the absorbent sheet facing the inkjet head is sucked by the suction device, and the portion of the absorbent sheet facing the inkjet head And the print medium are separated, and the absorbent sheet Serial and feature to convey the print medium in a state of being spaced apart from the portion and the print medium opposite to the ink jet head.

A second aspect further includes an adhesive sheet having an adhesive layer in which an adhesive is applied to both sides of the tape-like sheet in the first aspect, and both end portions of the absorbent sheet in the transport direction of the print medium are provided. the fixed by an adhesive layer on the platen, when the print media is aspirated, the print media and feature to be conveyed while rubbing the surface opposite to the adhesive layer of the absorbent sheet To do.

  A third aspect is characterized in that, in the first aspect, the absorbent sheet is fixed to the platen via a wire.

  A fourth aspect further includes a winding device that pulls the print medium in a transport direction when printing the print medium in the first aspect, and the print medium is stretched by the winding device, The print medium is brought into contact with the surface of the absorbent sheet where the absorbent sheet is fixed to the platen and the surface on the print media side, and the print medium is separated from the portion of the absorbent sheet facing the inkjet head. And

  According to a fifth aspect, in the first aspect, a film or a wire is fixed to both end portions in the transport direction on the side opposite to the platen of the absorbent sheet, and the print medium is in contact with the film or the wire. It is transported.

  According to a sixth aspect, in the first aspect, a concave wall that forms a concave portion including ends of the plurality of through walls is provided on the inkjet head side of the platen, and the absorbent sheet is sucked by the concave portion. It is characterized by that.

  A seventh aspect is characterized in that, in the first aspect, the ink adhering to the absorbing sheet and vaporized is sucked by the suction device.

  An eighth aspect is characterized in that, in the first aspect, the absorbent sheet is disposed on the platen over the width of the print medium.

  According to a ninth aspect, in the first aspect, the absorbent sheet is a nonwoven fabric including any one or more of polyester, polyethylene, nylon, and cotton, and after the ink has adhered to the absorbent sheet, the ink is The ink is dried before it penetrates and reaches the back surface of the absorbent sheet.

A tenth aspect is characterized in that, in the ninth aspect, the basis weight of the nonwoven fabric is 40 g / m ² or more.

  An eleventh aspect is characterized in that, in the first aspect, both end portions of the absorbent sheet in the transport direction of the print medium are thicker than a central portion.

  A twelfth aspect is characterized in that, in the first aspect, the apparatus further comprises a heater for heating the platen, and the ink adhering to the absorbent sheet is heated to promote vaporization of the ink.

  According to a thirteenth aspect, there is provided an interval in which the central portion of the nonwoven fabric is bent along the longitudinal direction of the sheet-like nonwoven fabric, and a spacer coated with an adhesive is fixed to the nonwoven fabric, and an inkjet recording apparatus It is an absorption sheet which absorbs the ink discharged from.

  According to a fourteenth aspect, in the thirteenth aspect, the spacer is made of the same material as the absorbent sheet.

  In the present invention, since the ink that has passed through the printing medium adheres to the absorbent sheet, the platen can be prevented from being stained with ink. In the present invention, the ink attached to the absorbent sheet does not adhere to the back surface of the print medium and become dirty because the print medium and the absorbent sheet are separated from each other. In addition, since the absorbing sheet is heated by the platen and sucked by the negative pressure generated by the fan, the volatile components of the ink are easily vaporized, and the ink adhering to the absorbing sheet is quickly dried, which can be used for printing media and operators. Since it becomes difficult for ink to adhere, handling of the absorbent sheet during replacement of the absorbent sheet or print medium becomes easy.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing a main configuration of an ink jet recording apparatus according to the present invention.

  An ink jet printer will be described as an example of the ink jet recording apparatus. The ink-jet head 1 is an ink-jet head that ejects ink by a heating element or a piezoelectric element. The platen 2 is a metal plate in which plantain through walls 13 are provided on the platen 2 and through holes are formed. A heater 7 is disposed on the back side of the platen 2, and the heater 7 heats the platen 2. The platen 2 is a plate-like platen provided to face the inkjet head 1. The print medium 4 is a mesh sheet made of resin or paper in which a print medium through wall 14 is provided in the print medium 4 and through holes are formed at an aperture ratio of 10 to 50%. The absorbent sheet 3 is a nonwoven fabric, preferably a nonwoven fabric containing at least one of polyester, polyethylene, nylon, and cotton. By using a non-woven fabric, the eyes are fine and the ink can be quickly absorbed and dried by capillary action and suction. Both end portions of the absorbent sheet 3 are fixed to the platen 2 via the spacer 21 with an adhesive.

  A duct 10 is provided on the back surface of the platen 2, and the duct 10 sucks air by a fan 22 and exhausts it from the exhaust port 11. When the fan 22 starts operation, air flows in the direction of the arrow 15 indicating the air flow direction, that is, in the direction of the fan 22 from the platen 2. Further, the air sucked by the fan 22 in the direction of the arrow 12 indicating the traveling direction of the exhaust gas is exhausted from the exhaust port 11.

  The print medium 4 is transported by being sandwiched between a rotationally driven transport roller 9 and a pinch roller 8 that is rotatably attached. Among the ink droplets 6 ejected from the ink jet head 1, there are ink droplets 16 that have passed through the opening of the print medium 4, but they do not reach the platen 2 like the ink droplets 17 attached to the absorbent sheet 3. Some of them adhere to the surface of the absorbent sheet 3.

  When the fan 22 operates and suction is started, the absorbent sheet 3 is stuck to the platen 2. In addition, when the fan 22 is not in operation, the absorbent sheet 3 does not stick to the platen 2 and is separated from the platen 2 as in the state of the absorbent sheet 5 at the time of non-suction, for example.

  The guide 18 is a plate that supports the print medium 4 when the print medium 4 is bent. The media take-up device 20 is a device that takes up the print media 4. In a state in which the print medium 4 is wound during printing and the drive speed of the print medium 4 is controlled by the conveying roller 9 and the pinch roller 8, the media winding device 20 winds the print medium 4 so that the print medium 4 is stretched. take. Further, the conveyance direction of the print medium 4 is changed with the guide roller 19 as a fulcrum.

  A portion of the platen 2 facing the inkjet head 1 is covered with at least an absorbent sheet 3. The absorbent sheet 3 is fixed to the platen 2 via spacers 21 at both ends of the absorbent sheet 3 in the transport direction of the print medium 4. The absorption sheet 3 is not deformed at the portion connected to the spacer 21 by suction, but is unexpectedly pulled in the direction of the platen 2, and at least the portion facing the inkjet head 1 sticks to the platen 2. This is because when the ink ejected by the inkjet head 1 adheres to the absorbent sheet 3, the portion of the absorbent sheet 3 to which the ink has adhered contacts the print media 4, and the ink adheres to the back surface of the print media 4. This is to prevent it.

  The ink adhering to the absorbent sheet 3 is heated by the heater 7 to promote the vaporization of the ink solvent. Since the absorption sheet 3 sticks to the platen 2 by being sucked, heat is more effectively transferred than when not sucked. Further, since air is sucked through the through-holes of the platen 2, vaporization of the ink solvent is further promoted, and the vaporized solvent is sucked. The sucked air is exhausted from the exhaust port 11. By disposing a filter for removing the vaporized solvent between the duct 10 and the exhaust port 11, the air from which the solvent component has been removed can be exhausted.

  The print medium 4 is in a tensioned state during printing. Further, when the absorbent sheet 3 is sucked, the spacer 21 portion of the absorbent sheet 3 is convex, so that the ink adhering to the absorbent sheet 3 is removed from the print medium 4. Can be prevented. Furthermore, since the ink attached to the absorbent sheet 3 can be quickly dried, the ink attached to the absorbent sheet 3 is further prevented from attaching to the back surface of the print medium 4.

  Further, the height of the transport roller 9, the spacer 21, and the guide roller 19 is set so that the spacer 21 is the highest so that the back surface of the print medium 4 is connected to the spacer 21 of the absorbent sheet 3. Since the print medium 4 is conveyed while being in contact with the ink, the height of the print medium 4 can be kept constant, and the ink adhering to the absorbent sheet 3 is prevented from adhering to the back surface of the print medium 4 without deteriorating the print quality. is doing.

  The ink attached to the absorbent sheet 3 will be described with reference to FIGS. FIG. 2 is a schematic cross-sectional view when the ink adheres to the absorbent sheet in the ink jet recording apparatus of the present invention. FIG. 3 is a schematic cross-sectional view of the ink jet recording apparatus of the present invention when ink is attached to the absorbent sheet and then dried.

The absorbent sheet 3 is adsorbed on the platen 2. The platen 2 is heated by the heater 7, and the heat is transmitted from the back surface of the platen 2 toward the absorbent sheet 3 as indicated by an arrow 23 indicating the flow of heat during heating. The platen 2 has a plantain through wall 13, and when sucked by the fan 22, air flows in the direction of an arrow 15 indicating the air flow direction during suction, and the absorbent sheet 3 sticks to the platen 2. Heat heats the ink droplets 17 attached to the absorbing sheet 3 through the absorbing sheet 3. The ink has components of a resin 24 such as a solvent 24 and a pigment. The adhering ink is sucked into the absorbent sheet 3 by the suction of the fan 22 and capillary action, and the solvent 24 and the resin 25 dried before soaking into the absorbent sheet 3 are fixed on the absorbent sheet 3. Since the solvent 24 permeates into the absorbent sheet 3 while diffusing, the area heated by the heater 7 increases, vaporization by heating is promoted, and the drying time is shortened. In addition, the absorbent sheet 3 is obtained in advance by experiments or the like having sufficient density and thickness to be dried before the solvent 24 reaches the platen 2. Since ink quickly enters the absorbent sheet 3 by suction, it can be further prevented from adhering to the back surface of the print medium 4. If the density of the fibers is too small, the attached ink reaches the platen 2, so that the basis weight of the nonwoven fabric is preferably 40 g / m ² or more, more preferably the basis weight of the nonwoven fabric is 60 g / m ² or more. The thickness is preferably 3 mm or less, more preferably 2 mm or less.

  FIG. 4 is a schematic cross-sectional view of a connecting portion between a platen and an absorbing sheet in another embodiment of the ink jet recording apparatus of the present invention. When the absorbent sheet 3 is sucked, the spacer 21 for providing a step in the absorbent sheet 3 is a wire 26. When the wire 26 is used as the spacer 21, since the wire 26 has a circular cross section, the shape of the absorbent sheet 3 on the print medium 4 side is an arc shape, and the contact area between the absorbent sheet 3 and the print medium 4 is smaller than that of the planar shape. Therefore, the frictional force can be reduced and smooth conveyance can be achieved.

  Further, another mode for fixing the absorbent sheet 3 to the platen 2 will be described with reference to FIGS. 5 and 6.

  FIG. 5 is a schematic cross-sectional view showing the connection between the platen and the absorbing sheet in still another embodiment of the ink jet recording apparatus of the present invention. FIG. 6 is a schematic cross-sectional view showing the connection between the platen and the absorbing sheet in still another embodiment of the ink jet recording apparatus of the present invention. In this structure, the absorbent sheet 3 is arranged on the platen 2, and the wire 26 or the film 27 is fixed to both ends of the absorbent sheet 3 in the transport direction of the print medium 4. The print medium 4 is conveyed so as to rub the wire 26 or the film 27. Since the gap corresponding to the diameter of the wire 26 or the thickness of the film 27 can be provided between the print medium 4 and the absorbent sheet 3, it is possible to prevent the ink adhered to the absorbent sheet 3 from adhering to the print medium 4.

  Next, the case where the platen 2 is in another form will be described with reference to FIGS. FIG. 7 is a schematic cross-sectional view showing the structure of a platen of another embodiment of the ink jet recording apparatus of the present invention. FIG. 8 is a schematic plan view showing the structure of the platen of another embodiment of the ink jet recording apparatus of the present invention. The print medium 4 is conveyed in the direction of the arrow in the figure. The platen through wall 13 that forms the through hole of the platen 2 is divided into a plurality of groups, for example, a group of two rows in the transport direction, and a depression on the surface of the platen 2 so that the end of the platen through wall 13 of that group is included. The concave wall 28 is formed to form a concave portion. In order to make the inside of the concave wall 28 as uniform as possible, the platen through walls 13 are arranged in a zigzag manner.

  Due to such a concave wall 28, when the absorbing sheet 3 is sucked by the fan 22, the directly sucked area becomes larger than when only the platen through wall 13 is sucked. As a result, the suction force of the ink adhering to the absorbent sheet 3 that differs depending on the location can be sucked with almost the same suction force at any location. Further, the absorbent sheet 3 needs to be arranged at least in an area where the ink is ejected from the inkjet head 1. Further, by making the absorbent sheet 3 the same as the width of the platen 2 and disposing the double-sided tape 32 on both ends of the absorbent sheet 3, when the absorbent sheet 3 is fixed to the platen 2, the end of the platen 2 becomes a mark and is attached. In addition, the absorbent sheet 3 is covered over the entire width of the platen 2, and the platen 2 can be prevented from being stained with ink.

  In the double-sided tape 32, the first adhesive portion 29 and the second adhesive portion 31 are arranged on both surfaces of the tape portion 30, one of which is adhesively fixed to the tape portion 30 and the absorbent sheet 3, and the other is adhesively fixed to the tape portion 30 and the platen 2. To do. One side of the double-sided tape 32 can be bonded and fixed to the absorbent sheet 3 in advance and used to fix to the platen 2 when necessary. Since the length of the absorbent sheet 3 used according to the width of the print medium 4 changes, the absorbent sheet 3 having a predetermined width may be used, but it is necessary when the absorbent sheet 3 is used in a roll shape in advance. It is desirable to cut a long length.

  9A and 9B are schematic cross-sectional views showing the structure of another embodiment of the absorbent sheet of the ink jet recording apparatus of the present invention. In this structure, both ends of the absorbent sheet 3 are made thicker than the center using the same material. In the bent portion 34, both end portions of the absorbent sheet 3 are bent. For example, it is fixed by welding or bonding so that the bent portion does not peel off. The bent end portions of the absorbent sheet 3 are bonded to the platen 2 by an adhesive layer 33 containing an adhesive. The bent part can be used on the platen 2 side or on the opposite side. When the bent part is on the platen 2 side, the bent part has the same function as the spacer 21. Further, when the bent portion is on the side opposite to the platen 2, the bent portion 35 has the same function as the wire 26 and the film 27 described in FIG. 5 or FIG. By using the same material as the absorbent sheet 3, the number of parts can be reduced.

  Here, the absorbent sheet 3 and the platen 2 are preferably fixed at the portion where the print medium 4 and the absorbent sheet 3 are in contact. For example, the absorbent sheet 3 is fixed at both ends in the transport direction of the print medium 4. preferable. However, the present invention is not limited to this, and it may be fixed outside the range where ink is ejected by the inkjet head 1 or may be fixed so as to avoid the through hole of the platen 2. The absorbent sheet 3 is preferably fixed to the platen 2, but may be fixed to a member outside the platen 2.

  Here, in the absorbent sheet 3 described above, the both ends of the absorbent sheet 3 in the transport direction of the print medium 4 are made thicker than the central portion, so that the spacer 21, the wire 26, and the film 27 separate from the absorbent sheet 3 can be used. Can be used as Both end portions of the absorbent sheet 3 in the transport direction of the print medium 4 can be thickened only on one side, and both sides can be thickened. The absorbent sheet 3 having an adhesive applied to the thickened portion is bonded to the platen 2 and fixed. By doing so, parts such as the spacer 21, the wire 26, and the film 27 are not required, and the structure is further simplified.

It is sectional drawing which shows typically the principal part structure of the inkjet recording device of this invention. It is a typical sectional view when ink adheres to an absorption sheet in the ink jet recording device of the present invention. FIG. 3 is a schematic cross-sectional view when the ink is dried after adhering to the absorbent sheet in the inkjet recording apparatus of the present invention. It is typical sectional drawing of the connection part of the platen and absorption sheet of another embodiment of the inkjet recording device of this invention. It is typical sectional drawing which shows the connection of the platen and absorption sheet of another embodiment of the inkjet recording device of this invention. It is typical sectional drawing which shows the connection of the platen and absorption sheet of another embodiment of the inkjet recording device of this invention. It is a typical sectional view showing the structure of the platen of another embodiment of the ink jet recording apparatus of the present invention. It is a typical plane which shows the structure of the platen of another embodiment of the inkjet recording device of this invention. It is typical sectional drawing which shows the structure of another embodiment of the absorption sheet of the inkjet recording device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet head 2 Platen 3 Absorbing sheet 4 Print media 6 Ink droplet 7 Heater 8 Pinch roller 9 Transport roller 10 Duct 11 Exhaust port 20 Media take-up device 26 Wire 28 Recessed wall

Claims (14)

In an inkjet recording apparatus comprising: a conveying unit that conveys a print medium; and an inkjet head that ejects ink to the print medium conveyed by the conveying unit.
A platen having a through wall forming a through hole;
A suction device for sucking and exhausting air from the through hole by a fan;
An absorbent sheet disposed in a portion facing the inkjet head on the platen,
When printing on the media, suction is performed by the suction device so that the portion of the absorbent sheet facing the inkjet head is adsorbed to the platen, and the portion of the absorbent sheet facing the inkjet head and the print medium were separated, the ink jet recording apparatus according to feature to convey the print medium in a state in which said the portion facing the ink jet head is spaced and said printing medium of said absorbent sheet. Further comprising an adhesive sheet having an adhesive layer coated with an adhesive on both sides of the tape-like sheet, fixing both ends of the absorbent sheet in the transport direction of the print medium to the platen by the adhesive layer, when the print medium is aspirated, the print medium is an inkjet recording apparatus according to claim 1, feature to be conveyed while rubbing the surface opposite to the adhesive layer of the absorbent sheet.   The inkjet recording apparatus according to claim 1, wherein the absorbing sheet is fixed to the platen via a wire.   The printing medium further includes a winding device that pulls the printing medium in a conveying direction, and the printing medium is stretched by the winding device, and the printing medium is placed on the absorbent sheet of the absorbent sheet. 2. The ink jet recording apparatus according to claim 1, wherein a part fixed to the platen is brought into contact with a surface on the print medium side, and the print medium is separated from a part of the absorbent sheet facing the ink jet head.   The film or wire is fixed to both end portions in the transport direction opposite to the platen of the absorbent sheet, and the print medium is transported while being in contact with the film or the wire. The ink jet recording apparatus described.   2. The inkjet according to claim 1, wherein a recess wall that forms recesses including ends of the plurality of through walls is provided on the inkjet head side of the platen, and the absorbing sheet is sucked by the recess. Recording device.   2. The ink jet recording apparatus according to claim 1, wherein the ink adhering to the absorbing sheet and vaporized is sucked by the suction device.   The inkjet recording apparatus according to claim 1, wherein the absorbent sheet is disposed on the platen over a width of the print medium.   The absorbent sheet is a nonwoven fabric including any one or more of polyester, polyethylene, nylon, and cotton, and after the ink adheres to the absorbent sheet, before the ink penetrates and reaches the back surface of the absorbent sheet. The inkjet recording apparatus according to claim 1, wherein the ink is dried.   The inkjet recording apparatus according to claim 9, wherein the nonwoven fabric has a basis weight of 40 g / m 2 or more.   The inkjet recording apparatus according to claim 1, wherein both end portions of the absorbent sheet in the transport direction of the print medium are thicker than a central portion.   2. The ink jet recording apparatus according to claim 1, further comprising a heater for heating the platen, wherein the ink adhering to the absorbing sheet is heated to promote vaporization of the ink.   A space with a width at which the central portion of the nonwoven fabric bends is provided along the longitudinal direction of the sheet-like nonwoven fabric, and a spacer coated with an adhesive is fixed to the nonwoven fabric to absorb ink ejected from the inkjet recording apparatus. Absorbing sheet to do.   The absorbent sheet according to claim 13, wherein the spacer is made of the same material as the absorbent sheet.

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