JP2008188930A - Apparatus for maintenance of inkjet head, inkjet head, inkjet recording apparatus, and method for maintenance of inkjet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for maintenance of an inkjet head capable of maintaining the inkjet head efficiently, in a short time, surely without damaging the substrate of a delivering opening. <P>SOLUTION: The apparatus for maintenance of the inkjet head is characterized by including a removing unit equipped with a suction member in which at least one first suction opening with a direction parallel to the orientation direction of the delivering opening as the longitudinal direction and at least one second suction opening with a direction parallel to the orientation direction of the delivering opening as the longitudinal direction are separated from each other in the direction orthogonal to the orientation direction of the delivering opening and are opened in parallel opposite the face on which the delivering opening is formed of the head substrate, arranged at a position which is not brought into contact with the head substrate, on a face opposite the face on which the delivering opening is formed of the head substrate, and a suction pump for sucking air in the suction member. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a maintenance device for an inkjet head that ejects ink as droplets, and more specifically, an inkjet head maintenance device in which a plurality of ejection portions that eject ink droplets are formed, an inkjet head having the maintenance device, and an inkjet head The present invention relates to an inkjet recording apparatus having a maintenance apparatus and an inkjet head maintenance method.

  As a method for recording an image on a recording medium, there is a recording method in which an ink jet head having an ejection port for ejecting ink droplets is used and ink droplets are ejected from the ejection ports in accordance with an image signal.

In an ink jet head that ejects ink droplets from such ejection ports, ink droplets may adhere to the surface of a nozzle plate (head substrate) on which ejection ports (nozzles) are formed.
When such ink droplets adhere to the nozzle plate, particularly around the ejection opening, there is a problem that the ink ejection direction becomes unstable and a high-quality image cannot be formed.
As a method for removing ink droplets and dirt adhering to the surface of the nozzle plate, the surface is rubbed and removed with a plate-like blade made of a flexible material, or ink droplets and dirt are absorbed. There is a method in which a member is brought into contact with a nozzle plate and absorbed.
However, if the nozzle plate material is not very hard to improve the nozzle hole manufacturing accuracy during head manufacture, that is, if a material with low hardness is used, or if the surface of the nozzle plate is subjected to liquid repellent treatment, A method using such a blade or absorber and involving physical contact may destroy the edge structure of the nozzle or damage the liquid-repellent surface.
If the edge structure of the nozzle is destroyed or the liquid repellent surface is damaged, the ejection of ink droplets is disturbed, and a high-quality image cannot be formed.
Here, as an apparatus for removing ink droplets adhering to the surface of the discharge port substrate, for example, there are maintenance apparatuses shown in Patent Documents 1 and 2.

  Patent Document 1 discloses a maintenance device for an inkjet head in which a large number of nozzles are arranged in a head body and the head body end is formed in a flat shape, and generates negative pressure lower than atmospheric pressure. Means, a local suction means connected in communication with the negative pressure generating means, the suction opening being formed in a size facing one or several units of the nozzle region, and the suction opening of the local suction means An ink jet head maintenance device is described that includes suction opening moving means for relatively moving in the arrangement direction.

Also, in Cited Document 2, when maintenance is required, such as ink adhering to the nozzle plate, the cap is moved to a position where the distance L between the cap rubber and the nozzle plate surface on the front surface of the head becomes a predetermined distance. There is described an ink ejecting apparatus that sucks ink on the nozzle plate surface into a cap by driving a pump in this state.
Further, it is described that the ink ejecting apparatus can remove ink without deterioration of the water-repellent film in the form of a nozzle plate.

JP 05-201028 A Japanese Patent Laid-Open No. 08-58103

  As described in the cited document 1 and the cited document 2, it is possible to prevent the surface of the discharge port substrate from being damaged during maintenance by performing suction from a position spaced apart from the discharge port substrate by a certain distance.

  However, since the inkjet head maintenance apparatus described in the cited document 1 needs to relatively move the suction port of the local suction unit toward the arrangement direction of the nozzles (discharge ports) by the suction opening moving unit, There is a problem that processing takes time and the apparatus becomes complicated. In the case of an inkjet head in which a large number of ejection openings are formed on the head substrate, this problem becomes significant.

Further, in the ink ejecting apparatus described in the cited document 2, there is no description about the case where a plurality of nozzles (discharge ports) are formed.
Here, for example, when one cap is disposed for a plurality of nozzles, there is a problem that ink between adjacent nozzles may remain on the nozzle plate (head substrate, discharge port substrate). There is also a problem that a large pump is required as a pump.
Further, for example, when a cap is provided for each of a plurality of nozzles, there is a problem that the apparatus configuration is complicated. In particular, there is a problem that it is difficult to form a cap in an ink jet head in which nozzles are arranged at fine intervals.

SUMMARY OF THE INVENTION An object of the present invention is to provide an inkjet head maintenance device that can solve the problems based on the above-described conventional technology, perform maintenance of the inkjet head efficiently, in a short time, and without damaging the discharge port substrate. Is to provide.
In addition, a second object of the present invention is to provide an inkjet head that can solve the problems based on the above-described conventional technology, perform maintenance efficiently, in a short time, and without damaging the discharge port substrate. It is to provide.
The third object of the present invention is to solve the problems based on the above-mentioned conventional technology, and to maintain the inkjet head efficiently, in a short time, and without damaging the discharge port substrate. It is to provide an ink jet recording apparatus.
The fourth object of the present invention is to solve the problems based on the above-mentioned conventional technology, and to maintain the inkjet head efficiently, in a short time, and without damaging the discharge port substrate. An object of the present invention is to provide a maintenance method for an inkjet head.

In order to solve the above problems, a first aspect of the first aspect of the present invention is a maintenance device for an inkjet head in which a plurality of ejection openings for ejecting ink droplets are formed in a row on a head substrate. ,
The surface of the head substrate facing the surface on which the discharge port is formed and not touching the head substrate is disposed on the surface of the head substrate facing the surface on which the discharge port is formed. At least one first suction port whose longitudinal direction is a direction parallel to the arrangement direction of the outlets and at least one second suction port whose longitudinal direction is a direction parallel to the arrangement direction of the discharge ports are the discharge ports. A removal unit comprising suction members opened in parallel and spaced apart from each other in a direction orthogonal to the arrangement direction;
The present invention provides a maintenance device for an ink jet head having a suction pump for sucking air in the suction member.

Here, the suction member preferably includes a first suction member in which the first suction port is formed and a second suction member in which the second suction port is formed.
The suction member has an opening diameter R [mm] in a direction orthogonal to the arrangement direction of the discharge ports, and a size of the suction port L in a direction orthogonal to the arrangement direction of the discharge ports L [mm]. mm], an interval between the first suction port and the second suction port in a direction orthogonal to the arrangement direction of the discharge ports is preferably (R + L + 2) [mm] or less.
The first suction port of the suction member is disposed at a position facing one end of the discharge port in a direction orthogonal to the arrangement direction of the discharge ports, and the second suction port of the suction member Is preferably arranged at a position facing the other end of the discharge port in a direction perpendicular to the arrangement direction of the discharge ports.
The removal unit is further disposed adjacent to the suction member, and is parallel to the arrangement direction of the discharge ports of the inkjet head on a surface of the head substrate that faces the surface where the discharge ports are formed. It is preferable to have a blowout member having at least one blowout opening whose direction is the longitudinal direction, and a blowout pump for supplying air to the blowout member.
Moreover, it is preferable that the said blower outlet of the said blowing member is arrange | positioned between the said 1st suction port and the said 2nd suction port in the direction orthogonal to the arrangement direction of the said discharge port.

In order to solve the above problems, a second form of the first aspect of the present invention is an ink jet head maintenance apparatus in which a plurality of ejection openings for ejecting ink droplets are formed in a line on a head substrate. There,
The ink jet is disposed on a surface of the head substrate facing the surface on which the ejection port is formed and not contacting the head substrate, and facing the surface on which the ejection port of the head substrate is formed. A suction member having at least one suction port having a longitudinal direction parallel to the arrangement direction of the ejection ports of the head as a longitudinal direction and the suction member of the head substrate are formed adjacent to the suction member. A removal unit comprising a blowing member having at least one blower outlet having a longitudinal direction parallel to the arrangement direction of the discharge ports of the inkjet head as a longitudinal direction on a surface opposed to the surface being formed;
A suction pump for sucking air in the suction member;
The present invention provides a maintenance device for an ink jet head having a blowing pump for supplying air to the blowing member.

Here, it is preferable that the suction port and the outlet have a length in the arrangement direction of the discharge ports longer than the arrangement interval of the discharge ports arranged in a row.
Furthermore, it is preferable to have an immersion mechanism that discharges ink from the ejection port of the inkjet head and wets the surface of the head substrate on which the ejection port is formed when the suction pump is stopped.
The dipping mechanism is further disposed at a position facing the surface of the head substrate on which the discharge port is formed and not in contact with the head substrate to form the discharge port of the head substrate. It is preferable to have a liquid flow guide that forms a flow path of ink discharged from the inkjet head between the surface and the surface.
Furthermore, it is preferable to have a removal unit attaching / detaching mechanism that moves the removal unit in a direction orthogonal to the surface of the head substrate on which the discharge port is formed when the suction pump is stopped.
In the suction member, it is preferable that a plurality of the first suction ports and a plurality of the second suction ports are opened in directions parallel to the arrangement direction of the discharge ports.

In order to solve the above-described problem, a first form of the second aspect of the present invention includes a droplet discharge unit in which a plurality of discharge ports for discharging ink droplets are formed in a line on a head substrate;
The surface of the head substrate facing the surface on which the ejection port is formed and not in contact with the head substrate, the surface of the head substrate facing the surface on which the ejection port is formed, At least one first suction port whose longitudinal direction is a direction parallel to the arrangement direction of the discharge ports and at least one second suction port whose longitudinal direction is a direction parallel to the arrangement direction of the discharge ports are the discharge ports. A removal unit comprising suction members spaced apart and opened in parallel in a direction perpendicular to the arrangement direction of the outlets;
An ink jet head having a suction pump for sucking air in the suction member is provided.

In order to solve the above-described problem, a second form of the second aspect of the present invention includes a droplet discharge unit in which a plurality of discharge ports for discharging ink droplets are formed in a row on a head substrate;
The liquid is disposed on a surface of the head substrate facing the surface on which the discharge ports are formed and not in contact with the head substrate, and facing the surface of the head substrate on which the discharge ports are formed. A suction member having at least one suction port whose longitudinal direction is parallel to the arrangement direction of the discharge ports of the droplet discharge unit, and the discharge port of the head substrate, which is disposed adjacent to the suction member. A removal unit comprising a blowing member having a surface opposite to the surface on which is formed, at least one outlet having a longitudinal direction parallel to the direction of arrangement of the discharge ports of the droplet discharge unit as a longitudinal direction;
A suction pump for sucking air in the suction member;
The present invention provides an ink jet head having a blow pump for supplying air to the blow member.

In order to solve the above problem, a first form of the third aspect of the present invention is an inkjet head in which a plurality of ejection openings for ejecting ink droplets are formed in a row on a head substrate;
The surface of the head substrate facing the surface where the discharge port is formed and not contacting the head substrate, and the surface of the head substrate facing the surface where the discharge port is formed, At least one first suction port whose longitudinal direction is parallel to the array direction of the discharge ports and at least one second suction port whose longitudinal direction is the direction parallel to the array direction of the discharge ports are the discharge ports A removal unit comprising suction members that are spaced apart from each other in the direction orthogonal to the arrangement direction of
An ink jet recording apparatus having a suction pump for sucking air in the suction member is provided.

In order to solve the above-mentioned problem, a second form of the third aspect of the present invention is an inkjet head in which a plurality of ejection openings for ejecting ink droplets are formed in a row on a head substrate;
The inkjet head is disposed on a surface of the head substrate that faces the surface on which the ejection ports are formed and that does not contact the head substrate, and that faces the surface on which the ejection ports are formed. A suction member having at least one suction port whose longitudinal direction is parallel to the direction in which the discharge ports are arranged, and the suction member disposed adjacent to the suction member to form the discharge port of the head substrate. A removal unit comprising a blowing member having at least one blower outlet having a longitudinal direction parallel to the arrangement direction of the discharge ports of the inkjet head as a longitudinal direction on a surface facing the surface of the inkjet head;
A suction pump for sucking air in the suction member;
The present invention provides an ink jet recording apparatus having a blowing pump for supplying air to the blowing member.

In order to solve the above problems, a fourth aspect of the present invention is a maintenance method for an inkjet head in which a plurality of ejection openings for ejecting ink droplets are formed in a row on a head substrate,
Discharging ink from the discharge port, wetting the surface of the head substrate on which the discharge port is formed with the ink,
There is a suction port whose longitudinal direction is the arrangement direction of the discharge ports, and a suction member that sucks air from the suction port does not contact a plurality of the discharge ports on the surface of the head substrate on which the discharge ports are formed Close to the position,
The present invention provides a maintenance method for an ink jet head that sucks at least one of air and ink from the suction port and sucks deposits around the discharge port of the head substrate.

Further, at the same time as the suction member, there is a blower outlet in which the arrangement direction of the discharge outlets is the longitudinal direction, and a blower member for injecting air from the blower outlet is formed on the surface on which the discharge outlet of the head substrate is formed. Proximity to a position that does not contact a plurality of the discharge ports,
Preferably, at least one of air and ink is sucked from the suction port and air adhering around the discharge port of the head substrate is sucked while injecting air from the outlet to the vicinity of the discharge port.

  According to the present invention, it is possible to efficiently and quickly remove ink droplets and dirt around the ejection port on the surface of the head substrate where the ejection port is formed. As a result, the inkjet head can be maintained efficiently in a short time. Furthermore, the apparatus can be made inexpensive.

  BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an ink jet head maintenance apparatus according to a first embodiment of the present invention; an ink jet head according to a second aspect; an ink jet recording apparatus according to a third aspect; This will be described in detail based on the embodiment shown in FIG.

First, an example of a digital label printing apparatus using the ink jet recording apparatus according to the third aspect of the present invention which provides the ink jet head maintenance apparatus according to the first aspect of the present invention will be described.
1 is a schematic configuration diagram showing an example of a digital label printing apparatus 100, FIG. 2 is a longitudinal sectional view of a recording medium for label printing used in the digital label printing apparatus 100 shown in FIG. 1, and FIG. FIG. 2 is an enlarged schematic perspective view showing a drawing unit 112 of the digital label printing apparatus 100 shown in FIG. 1.

The digital label printing apparatus 100 according to the present embodiment is an ultraviolet curable inkjet digital label printing apparatus using an ultraviolet curable ink that is an active energy ray (active light) curable ink, and has a foil stamping unit and is capable of foil stamp printing. Label printing device.
Here, foil press printing is a method of pressing a foil such as a gold foil, a silver foil, a color foil, etc. on a book cover or spine against a mating member with a heated letterpress to heat-press (foil press) the foil. Also called a hot stamp.

  As shown in FIG. 1, the digital label printing apparatus 100 basically includes a transport unit 110, an undercoat unit 111, a drawing unit 112, a maintenance unit 114, a smoothing unit 116, a foil stamping unit 118, a label removing unit. Unit 120 and control unit 121. The control unit 121 controls various operations of the transport unit 110, the undercoat unit 111, the drawing unit 112, the maintenance unit 114, the smoothing unit 116, the foil pressing unit 118, and the label removing unit 120.

Here, the transport unit 110 transports a continuous paper-like recording medium P for label printing (hereinafter referred to as “recording medium P”) in a certain direction (from left to right in FIG. 1). The drawing unit 112, the smoothing unit 116, the foil pressing unit 118, and the label removing unit 120 are arranged in the order of the conveyance direction of the recording medium P, that is, from upstream to downstream, and the drawing unit 112, smoothing unit 116, foil pressing unit 118, label removing unit. The units 120 are arranged in this order. A maintenance unit 114 is disposed at a position of the drawing unit 112 that faces the recording medium P.
Here, as shown in FIG. 2, the recording medium P of the present embodiment has a two-sheet structure in which an adhesive sheet 180 coated with an adhesive 180a on the back surface is superposed on a release paper 182 as a mount. .

The conveyance unit 110 includes a supply roll 122, conveyance roller pairs 124, 126, 128, 130, and 132, and a product winding unit 134.
A continuous paper-like recording medium P for label printing (hereinafter referred to as “recording medium P”) is wound around the supply roll 122 in a roll shape. The conveyance roller pairs 124, 126, 128, 130, and 132 are driven to rotate by a conveyance motor (not shown), and the recording medium P is unwound from the supply roll 122 to draw the drawing unit 112, the smoothing unit 116, the foil pressing unit 118, and the label removal unit. It conveys to the part 120 sequentially.
The product winding unit 134 is disposed on the most downstream side in the conveyance direction of the recording medium P, and is conveyed by the conveyance roller pairs 124, 126, 128, 130, and 132. The drawing unit 112, the smoothing unit 116, the foil pressing unit 118, The recording medium P that has passed through the label removing unit 120 is wound up.

  The undercoat unit 111 includes an application roll 190 that applies the undercoat liquid to the recording medium P, a drive unit 191 that rotates the application roll 190, a blade 192 that adjusts the amount of the undercoat liquid that adheres to the application roll 190, and an application roll. A positioning unit 194 that supports the recording medium P so that the recording medium P is at a predetermined position with respect to 190, and an undercoat liquid is applied to the recording medium P on which an undercoat layer is formed, and ultraviolet rays are irradiated to the undercoat liquid. An undercoat liquid semi-cured portion 197 that makes the (undercoat layer) semi-cured.

The coating roll 190 is disposed on the downstream side of the supply roll 122 in the conveyance path of the recording medium P and in contact with the surface of the recording medium P on which the image is formed.
The application roll 190 is a roll longer than the width of the recording medium P, and is a so-called gravure roller in which concave portions are uniformly formed on the surface (outer peripheral surface) at regular intervals.
Here, the shape of the recess formed in the coating roll 190 is not particularly limited, and may be various shapes such as a circle, a rectangle, a polygon, and a star. Moreover, you may form a recessed part in groove shape in the perimeter of an application | coating roll.

The drive unit 191 is connected to the application roll 190, and rotates the application roll 190 in a direction opposite to the conveyance direction of the recording medium P (clockwise in FIG. 1).
The driving method by the driving unit 191 is not particularly limited, and various methods such as gear driving, pulley driving, belt driving, direct driving, and the like can be used.

The blade 192 is disposed in contact with the surface of the coating roll 190 on the downstream side in the conveyance direction of the recording medium P.
In addition, an undercoat liquid is stored in a space (hereinafter referred to as “storage section 193”) formed in an upper portion of a contact portion (contact portion) between the coating roll 190 and the blade 192. The reservoir 193 is supplied with an undercoat liquid from a supply tank (not shown) as necessary.
As a result, the application roll 190 comes into contact with the recording medium P after being immersed in the undercoat liquid in the reservoir 193.
The blade 192 immerses the coating roll 190 in the storage unit 193 to scrape off the undercoating liquid adhering more than necessary from among the adhering undercoating liquid, so that the adhesion amount of the undercoating liquid adhering to the coating roll 190 is constant. . Specifically, the blade 192 scrapes off the undercoat liquid adhering to other parts of the application roll 190 except for the undercoat liquid held in the recesses formed on the surface of the application roll 190.
As a result, the undercoat liquid held in the portion of the coating roll 190 that contacts the recording medium P can be only the undercoat liquid held in the recess. That is, the amount of the undercoat liquid that comes into contact with the recording medium P can be made constant.

The positioning unit 194 includes positioning rolls 195 and 196 and supports the recording medium P so that the recording medium P at a position in contact with the coating roll 190 is at a predetermined position. That is, the positioning unit 194 sets the transport path of the recording medium P at a position where the coating roll 190 and the recording medium P are in contact with each other as a predetermined position.
The positioning roll 195 is disposed on the surface opposite to the surface on which the image of the recording medium P is formed (the surface on which the undercoat liquid is applied) and in the transport direction of the recording medium P, It arrange | positions between the application | coating rolls 190. FIG.
The positioning roll 196 is a surface on the side opposite to the surface on which the image of the recording medium P is formed and in the transport direction of the recording medium P, and between the coating roll 190 and an undercoat liquid semi-curing portion 197 described later. Arranged between.
That is, the positioning rolls 195 and 196 are sandwiched between the coating roll 190 in the conveying direction of the recording medium P on the opposite side to the coating roll 190 via the recording medium P, that is, upstream of the coating roll 190. Are arranged on the downstream side.
The positioning rolls 195 and 196 support the recording medium P from the surface opposite to the surface on which the image of the recording medium P is formed.

The undercoat part 111 is configured as described above, and the drive part 191 rotates the application roll 190 in the direction opposite to the conveyance direction of the recording medium P. The surface of the rotating coating roll 190 is immersed in the undercoat liquid stored in the storage unit 193, and then comes into contact with the blade 192. After the amount of the undercoat liquid held on the surface is set to a constant amount, The undercoat liquid is applied on the recording medium P in contact with the recording medium P. Thus, by rotating the coating roll 190 in the reverse direction to the conveyance direction of the recording medium P and applying the undercoat liquid to the recording medium P, the coating roll 190 is smoothed and has a good coated surface shape without unevenness. A layer of undercoat liquid (hereinafter also referred to as “undercoat layer”) can be formed on the recording medium P.
The coating roll 190 in contact with the recording medium P further rotates and is immersed again in the undercoat liquid of the storage unit 193.
In this way, the undercoat unit 111 rotates the application roll 190 to apply the undercoat liquid to the surface of the recording medium P, thereby forming an undercoat layer on the surface of the recording medium P.

  Here, by rotating the coating roll 190 in the direction opposite to the conveyance direction of the recording medium P, the undercoat layer U having an improved surface shape can be formed on the recording medium P. That is, an undercoat layer having a small surface roughness can be formed on the recording medium P, thereby forming a high-quality image.

The undercoat liquid semi-curing portion 197 has a UV lamp and is disposed to face the conveyance path of the recording medium P. Here, the UV lamp is a light source that emits ultraviolet light, and various ultraviolet light sources such as a metal halide lamp and a high-pressure mercury lamp can be used.
The undercoat liquid semi-curing portion 197 irradiates the entire area in the width direction of the recording medium P passing through the facing position with ultraviolet rays.

  The undercoat liquid semi-curing unit 197 irradiates the recording medium P having the surface coated with the undercoat liquid passing through the opposing position, and irradiates the undercoat liquid applied to the surface of the recording medium P in a semi-cured state. To do. That is, the undercoat liquid semi-curing unit 197 sets the undercoat liquid applied on the recording medium P to a semi-cured state. The state where the undercoat liquid is semi-cured will be described in detail later.

The drawing unit 112 includes a recording head unit 135, an ink storage / loading unit 137, and an ultraviolet irradiation unit 138.
The recording head unit 135 has recording heads (hereinafter also referred to as “inkjet heads”) 136Y, 136C, 136M, and 136K, and is positioned at a position facing the conveyance path of the recording medium P, that is, an ejection that ejects ink droplets. The front end of the part is arranged to face the recording medium P.

The recording heads 136Y, 136C, 136M, and 136K are inkjet heads that discharge yellow (Y), cyan (C), magenta (M), and black (K) ink from the discharge unit, respectively. The recording head 136Y, the recording head 136C, the recording head 136M, and the recording head 136K are arranged in this order from upstream to downstream in the transport direction. The recording heads 136Y, 136C, 136M, and 136K are connected to the ink storage / loading unit 137 and the control unit 121.
As shown in FIG. 3, the recording heads 136Y, 136C, 136M, and 136K include a plurality of ejection units in a region where the width in the direction perpendicular to the transport direction of the recording medium P exceeds the maximum width of the recording medium P to be transported. This is a full line type ink jet head in which (nozzles) are arranged in a line. The structure of the recording head will be described in detail later.

As in this embodiment, the recording head is a full-line type, so that the recording medium P and the drawing unit 112 are relatively 1 in the direction (sub-scanning direction) orthogonal to the extending direction of the ejection unit of the recording head. The image can be recorded on the entire surface of the recording medium P by being moved once (that is, by one scanning). Thereby, it is possible to perform high-speed printing as compared with the shuttle type head in which the recording head reciprocates in the main scanning direction, and productivity can be improved.
Further, a color image can be formed on the recording medium P by ejecting the color inks from the recording heads 136Y, 136C, 136M, and 136K while transporting the recording medium P.

The ink storage / loading unit 137 includes an ink supply tank that stores inks of colors corresponding to the recording heads 136Y, 136C, 136M, and 136K.
As the ink supply tank, for example, a system that replenishes ink into a tank from a replenishing port (not shown) or a cartridge system that replaces the entire tank when the ink remaining amount is low can be used.
Each ink supply tank of the ink storage / loading unit 137 communicates with each recording head 136Y, 136C, 136M, 136K via a pipe line (not shown), and supplies ink to each recording head 136Y, 136C, 136M, 136K. To do.

The ultraviolet irradiation unit 138 is an active energy ray irradiation light source, and is arranged on the downstream side of each recording head 136Y, 136C, 136M, 136K corresponding to each recording head 136Y, 136C, 136M, 136K. As the ultraviolet irradiation unit 138, various ultraviolet light sources such as a metal halide lamp, a high-pressure mercury lamp, and a UVLED can be used.
The ultraviolet irradiation unit 138 passes the recording heads 136Y, 136C, 136M, and 136K, and irradiates the recording medium P on which the image is formed with ultraviolet rays. That is, the ultraviolet irradiation unit 138 gives the ink on the recording medium the energy that the ink ejected from the recording head and placed on the recording medium P is immediately cured, and the ink on the recording medium P is semi-cured, or Harden.

Here, the ultraviolet irradiation unit 138 has a position or configuration in which the emitted ultraviolet light is applied to the ink on the recording medium P and is not applied to the ink ejection ports of the recording heads 136Y, 136C, 136M, and 136K. It is preferable. In this way, by preventing the ink ejection port from being irradiated with ultraviolet rays, it is possible to prevent the ink from being cured at the ejection port.
Further, it is preferable to perform a light reflection preventing treatment (for example, a matte black treatment) on each part in the vicinity of the ultraviolet irradiation unit 138.

The maintenance unit 114 is disposed at a position facing the recording head unit 135 via the conveyance path of the recording medium P. The maintenance unit 114 is disposed on the surface side (back surface side) where the image of the recording medium P is not formed and at a position facing the recording head unit 135.
The maintenance unit 114 includes a plurality of maintenance devices 30 corresponding to the recording heads 136Y, 136C, 136M, and 136K.
The maintenance unit 114 and the maintenance device 30 will be described in detail later.

  Next, the smoothing unit 116 is disposed on the downstream side of the drawing unit 112 in the conveyance direction of the recording medium P, and is transparent on the surface of the recording medium P with an active energy ray (ultraviolet light in this embodiment) curable liquid ( Hereinafter, the varnish coater 142 which is a transparent liquid supply means for supplying "active energy curable transparent liquid" or simply "transparent liquid") and the foil donation range described later of the recording medium P are pressed and smoothed. It has a flat pressure member 146 and an ultraviolet irradiation unit 148 that is an active energy irradiation unit that irradiates and cures the transparent liquid with an active energy ray.

The varnish coater 142 has a pair of application rolls 144 and 145.
The coating rolls 144 and 145 have a transparent liquid attached (impregnated) on the surface, and are disposed at positions where the recording medium P conveyed by the conveying unit 110 is sandwiched. The application rolls 144 and 145 rotate in response to (synchronously with) the movement of the recording medium P while sandwiching the recording medium P, thereby passing through the drawing unit 112 and the recording medium on which an image is formed. A transparent liquid is applied to the surface of P (the surface on which the image is formed).

  Here, the transparent liquid applied by the varnish coater 142 is an active energy ray-curable transparent liquid that can be cured by ultraviolet irradiation, and includes at least a polymerizable compound and a photoinitiator as main components, for example, a cationic polymerization composition. Products, radical polymerization compositions, aqueous compositions, and the like.

The flat pressure member 146 is movable in the vertical direction (arrow direction shown in the figure) with the smooth surface 146a facing the recording medium P on the downstream side of the varnish coater 142 in the conveyance direction of the recording medium P. Is arranged in.
The flat pressure member 146 moves in the vertical direction, contacts the recording medium P, presses at least the surface (image surface) in the foil donation range of the recording medium P with the smooth surface 146a, and the recording medium P The ink that is ejected onto the surface of the ink and forms an image is smoothed.
The smooth surface 146a has at least an area larger than the foil donation range.

  The ultraviolet irradiation unit 148 is disposed on the downstream side of the flat pressure member 146 in the conveyance direction of the recording medium P. The ultraviolet irradiation unit 148 irradiates the recording medium P with active energy rays (ultraviolet rays in the present embodiment), and cures the smoothed transparent liquid applied to the surface of the recording medium P. As the ultraviolet irradiation unit 148, for example, a metal halide lamp, a high pressure mercury lamp, a UV-LED, or the like can be used.

  The varnish coater 142 and the ultraviolet irradiation unit 148 are not essential devices for smoothing the foil donation range of the recording medium P, but are installed because a smooth surface can be obtained by applying a transparent liquid. Is preferred.

The foil pressing unit 118 includes a foil supply roll 150, a foil winding roll 152, rollers 154 and 156, a foil 158, and a hot stamp plate 160, and the smoothing unit 116 in the conveyance direction of the recording medium P. It is arranged on the downstream side.
The foil supply roll 150 and the foil take-up roll 152 are arranged at a predetermined interval. Further, the roller 154 and the roller 156 are separated from each other by a predetermined distance, the surface connecting the roller 154 and the roller 156 is parallel to the surface of the recording medium P, and more than the foil supply roll 150 and the foil take-up roll 152. It is arranged at a position close to the recording medium P. The rollers 154 and 156 are arranged at positions very close to the recording medium P.
The foil 158 is supplied from the foil supply roll 150, wound around the roller 154 and the roller 156, and then stretched around the foil winding roll 152. Here, the foil 158 between the roller 154 and the roller 156 is parallel to the recording medium P.

The hot stamp plate (letter plate) 160 is disposed between the roller 154 and the roller 156 at a position facing the recording medium P via the foil 158. The hot stamp plate 160 is provided with a relief plate portion 160a that comes into contact with the foil 158 and presses the foil 158 on the surface of the recording medium P, and is formed of zinc, brass, or the like. Further, the hot stamp plate 160 has a heating device (not shown) for heating the relief plate portion 160a and a moving mechanism for moving the hot stamp plate 160 in a direction approaching or separating from the recording medium P.
The hot stamp plate 160 is heated and pressure-bonded on the recording medium P according to the shape of the relief plate portion 160a by bringing the heated relief plate portion 160a into contact with the recording medium P via the foil 158 and pressing it. To do.

Here, in the present embodiment, a transport buffer is provided between the smoothing unit 116 and the foil pressing unit 118.
By providing the transport buffer, it is possible to absorb the slack of the continuous paper-like recording medium P caused by the difference in transport speed between the smoothing unit 116 and the foil pressing unit 118, and it is possible to manufacture labels efficiently.

  The label removing unit 120 is disposed on the downstream side of the ultraviolet irradiation unit 164 in the conveyance direction of the recording medium P, and the active energy ray curable transparent liquid (in this embodiment, the ultraviolet curable transparent liquid) is applied to the image surface. A varnish coater 162 and an ultraviolet irradiation unit 164 for improving the gloss by being applied to the sheet, a die cutter 166 for making a label-shaped cut in the continuous paper-like recording medium P, and a residue removing unit 172 which is an unnecessary portion peeling unit. Have.

The varnish coater 162 is disposed on the downstream side of the foil pressing unit 118 in the conveyance direction of the recording medium P.
The varnish coater 162 has a pair of coating rolls (impregnated) with an ultraviolet curable transparent liquid attached to the surface thereof, and supports the movement of the recording medium P (synchronized) while sandwiching the recording medium P. By rotating, the ultraviolet curable transparent liquid is applied to the surface (the surface on which the image is formed) of the recording medium P pressed with foil.
The ultraviolet irradiation unit 164 is disposed on the downstream side of the varnish coater 162 in the conveyance direction of the recording medium P. The ultraviolet irradiation unit 164 irradiates the recording medium P with active energy rays (ultraviolet in the present embodiment) to cure the ultraviolet curable transparent liquid applied to the surface of the recording medium P.
By applying and curing an ultraviolet curable transparent liquid on the surface of the recording medium P, the image surface of the recording medium P can be given gloss, and the image quality can be improved.

As shown in FIG. 2, the die cutter 166 is provided with a desired label-shaped cut 180 b only in the adhesive sheet 180 of the printed continuous paper-like recording medium P, and in the transport direction of the recording medium P. A cylinder cutter 168 disposed on the downstream side of the ultraviolet irradiation unit 164 and disposed on the image surface side of the recording medium P, and a receiving roller 170 disposed on the opposite side of the cylinder cutter 168 across the recording medium P. Have
The cylinder cutter 168 includes a cylindrical cylinder 168a and a plurality of cutting blades 168b wound around the cylindrical surface of the cylinder 168a and formed in a label shape.

  The die cutter 166 oscillates and rotates intermittently in synchronization with the conveyance speed of the recording medium P while the recording medium P is sandwiched between the cylinder cutter 168 and the receiving roller 170, so that the cutting blade 168b is rotated. Only the P adhesive sheet 180 is cut into a label shape.

  Here, the reason why the die cutter 166 swings and rotates intermittently is to solve the problem caused by the discrepancy between the circumferential length of the cylindrical surface of the cylinder 168a and the required length of the cutting blade 168b. That is, when the die cutter 166 is continuously rotated to insert the label-shaped cut 180b, the recording medium P corresponding to the portion where the cutting blade 168b of the cylinder cutter 168 is not provided is also fed and the recording medium P is wasted. However, by rotating and rotating the die cutter 166, the cuts 180b can be formed continuously, and waste of the recording medium P can be eliminated.

The scrap removing part 172 peels off an unnecessary part (peripheral part of the label L) of the adhesive sheet 180 that does not become the label (product) L from the release paper 182 and winds it up.
The recording medium P in which the unnecessary portion is wound, that is, the recording medium P in which only the label L is attached to the release paper 182 is wound around the product winding unit 134 to become a product.

Hereinafter, the recording head unit 135 and the maintenance unit 114 of the drawing unit 112 will be described in detail.
First, the structure of the recording heads 136Y, 136C, 136M, and 136K will be described in detail. Here, since the recording heads 136Y, 136C, 136M, and 136K have the same configuration except for the color of the ejected ink, the recording head 136K will be described below as a representative.

  4A is a side view showing a schematic configuration of the recording head 136K, FIG. 4B is a bottom view showing an arrangement pattern of the ejection portions 12 of the recording head 136K, and FIG. FIG. 5 is a cross-sectional view taken along the line C-C showing a schematic configuration of a discharge portion of the recording head 136K in FIG.

In the recording head 136K, as shown in FIGS. 4A and 4B, a plurality of ejection units 12 for ejecting ink droplets are formed in a row on the head substrate 13 at regular intervals.
Here, the head substrate 13 is a plate-like member common to the plurality of ejection units 12. As the head substrate 13, various materials such as a resin material, a polymer material, and silicon can be used.

Hereinafter, one discharge unit 12 will be described.
As shown in FIG. 4C, the ejection unit 12 includes an ink chamber unit 14 formed on the head substrate 13 and an actuator 24.

The ink chamber unit 14 includes a nozzle 16, a pressure chamber 18, and a supply port 20, and is formed inside the head substrate 13.
The nozzle 16 is a tubular member that ejects ink droplets. One opening is formed on the surface of the head substrate 13 and faces the recording medium P, and the other opening is connected to the pressure chamber 18. . An opening formed in the surface of the head substrate 13 of the nozzle 16 becomes a discharge port 16a.
The nozzle 16 has a shape in which a part of the discharge port 16a side becomes smaller in diameter toward the discharge port 16a.
The pressure chamber 18 has a rectangular parallelepiped shape in which the plane shape perpendicular to the direction in which the ink droplets are ejected is a square, and both corners on the diagonal are connected to the nozzle 16 and the supply port 20.
The supply port 20 has one end connected to the pressure chamber 18 and the other end communicating with the common flow path 22.
As shown in FIG. 4A, the common flow path 22 is formed inside the head substrate 13, is connected to the ink chamber units 14 of the plurality of ejection units 12, and is further connected to the ink tank 60 via the supply pipe 61. Are also connected.

Next, the actuator 24 is disposed on a surface (top surface) opposite to the connection surface between the nozzle 16 and the supply port 20 of the pressure chamber 18, and includes a pressure plate 26 and an individual electrode 28.
In the actuator 24, the pressure plate 26 is deformed by applying a driving voltage to the individual electrode 28.

Here, the ink tank 60 connected to the common flow path 22 via the supply pipe 61 is a part of the ink storage / loading unit 137 described above, and supplies ink to the recording head 136K.
In addition, a filter 62, an ink pressurizing mechanism 64 of the maintenance unit 114, and an electromagnetic valve 66 are disposed in a supply pipe 61 that connects the ink tank 60 and the recording head 136 </ b> K.
The filter 62 removes foreign matters and bubbles mixed in the ink supplied from the ink tank 60 to the recording head 136K. The filter 62 preferably has a mesh size equal to or smaller than the nozzle diameter (as an example, 20 μm or smaller).
The ink pressurization mechanism 64 and the electromagnetic valve 66 will be described later.

The ink discharge method of the discharge part 12 is demonstrated.
First, ink is supplied from the ink tank 60.
The ink supplied from the ink tank 60 passes through the common flow path 22 and the common port 20 and is filled in the pressure chamber 18 and the nozzle 16. That is, the pressure chamber 18 and the nozzle 16 are filled with ink.
When a drive voltage is applied to the individual electrode 28 in a state where the pressure chamber 18 and the nozzle 16 are filled with ink, the pressure plate 26 is deformed, the pressure chamber 18 is pressurized, and is discharged from the discharge port 16 a of the nozzle 16. Ink is ejected. That is, by driving the actuator 24, ink droplets are ejected from the ejection port 16a of the nozzle 16.
When ink droplets are ejected from the nozzle 16, new ink is supplied from the common flow path 22 through the supply port 20 to the pressure chamber 18.
As described above, the drawing unit 112 forms an image on the recording medium P by discharging ink droplets from the discharge port 16 a of the nozzle 16.

Next, the maintenance unit 114 will be described in detail.
5 is a side view showing a schematic configuration of the recording head 136K of the recording head unit 135 of the drawing unit 112 and the maintenance device 30 of the maintenance unit 114, and FIG. 6 is a schematic configuration of the maintenance device 30 shown in FIG. FIG. 7 is a schematic perspective view showing the shape of the suction member shown in FIG. 6.

As described above, the maintenance unit 114 includes a plurality of maintenance devices 30 in the present embodiment, and the maintenance devices 30 are arranged corresponding to the recording heads 136Y, 136C, 136M, and 136K, respectively.
Since each maintenance device 30 has the same function and shape, the maintenance device 30 disposed at a position facing the recording head 136K will be described as a representative.

As shown in FIG. 5, the maintenance device 30 is disposed to face the surface of the recording head 136 </ b> K in which the discharge port 16 a of the head substrate 13 is formed (hereinafter also referred to as “discharge surface of the head substrate 13”). Yes. That is, the maintenance device 30 is disposed on the transport path side of the recording medium P of the recording head 136K.
The maintenance device 30 also has a direction in which the plurality of discharge ports 16a formed in the head substrate 13 are arranged (hereinafter also referred to as “array direction”), that is, a plurality of discharge ports 16a formed in a row. The length in the direction parallel to the line connecting the two is substantially the same as the length of the head substrate 13 or longer than the length of the head substrate 13. That is, the maintenance device 30 is formed with a length corresponding to all the ejection units 12 of the recording head 136K.

As shown in FIG. 6, the maintenance device 30 includes a removal mechanism 32 and a removal mechanism moving unit 34. Further, although not shown in FIG. 6, the removing mechanism 32 includes an ink pressurizing mechanism 64 and an electromagnetic valve 66 (see FIG. 4). The removal mechanism 32, the removal mechanism moving unit 34, the ink pressurizing mechanism 64, and the electromagnetic valve 66 are connected to the control unit 121 (see FIG. 1), and various operations are controlled by the control unit 121.
The removal mechanism 32 includes a first suction member 36, a second suction member 37, a support 42, an ink trap mechanism 46, and a suction pump 48.

As shown in FIG. 6, the first suction member 36 is disposed at a position facing the ejection unit 12 of the recording head 136K and not contacting (not contacting) the head substrate. It is a hollow box shape whose width becomes smaller as the part goes to the discharge part 12 side.
Further, the first suction member 36 has a slit 38 formed at the tip on the discharge unit 12 side, and a connecting pipe 40 is formed on a part of a surface (opposite surface) opposite to the surface where the slit 38 is formed. Is provided.

The second suction member 37 faces the discharge portion 12 of the recording head 136K and is spaced from the first suction member 36 by a predetermined interval in a direction orthogonal to the arrangement direction of the discharge ports 16a. It is arranged at a position where it does not contact (becomes non-contact).
The second suction member 37 has a symmetric shape with an axis parallel to the arrangement direction of the first suction member 36 and the discharge ports 16 a and orthogonal to the discharge surface of the head substrate 13. That is, the second suction member 37 has a hollow box shape that is disposed so as to face the ejection unit 12 of the recording head 136 </ b> K and has a width that decreases as a part of the ejection unit 12 side moves toward the ejection unit 12.
The second suction member 37 also has a slit 39 formed at the tip on the discharge unit 12 side, and the connecting pipe 41 is formed on a part of the surface opposite to the surface on which the slit 39 is formed (opposing surface). Is provided.

Here, the slit 38 of the first suction member 36 and the slit 39 of the second suction member 36 are spaced apart from each other in a direction orthogonal to the arrangement direction of the discharge ports 16a.
The slit 38 of the first suction member 36 is disposed at a position facing one end of the discharge port 16a in the direction orthogonal to the arrangement direction of the discharge ports 16a, and the slit 39 of the second suction member 37 is In the direction orthogonal to the arrangement direction of the discharge ports 16a, it is disposed at a position facing the other end of the discharge ports 16a. That is, the two slits 38 and 39 are respectively arranged to face both end portions of the discharge port 16a. That is, the slit 38 is disposed at a position where the opening sandwiches one end portion of the discharge port 16a, and the slit 39 is disposed at a position where the opening sandwiches the other end portion of the discharge portion 16a.

Further, as shown in FIG. 7, the first suction member 36 and the second suction member 37 are partially formed in a tube 45 with a cross-sectional shape at an arbitrary position in the longitudinal direction of the recording head 136K, that is, in the arrangement direction of the discharge ports 16a. The connection pipes 40 and 41 that are connected to each other have substantially the same shape except that they are formed.
That is, the slit 38 and the slit 39 are disposed to face the plurality of discharge ports 16a arranged in a row. That is, one slit 38 and one slit 39 are respectively arranged to face the plurality of ejection ports 16a.

  The tube 45 is a three-way pipe (tube) having one end branched into two, the two branched ends connected to the connecting pipes 40 and 41, and the other end connected to the suction pump 48. Yes. That is, the tube 45 allows the first suction member 36, the second suction member 37, and the suction pump 48 to communicate with each other.

  The suction pump 48 is a pump that sucks air, such as a vacuum pump or an air pump. The suction pump 48 sucks air in the first suction member 36 and the second suction member 37 through the tube 45, and the first suction member 36. And the inside of the second suction member 37 are set to a negative pressure.

  The removal mechanism 32 has such a configuration, and the air around the slit 38 is sucked into the suction member 36 from the slit 38 of the first suction member 36, thereby discharging the head substrate 13 at a position facing the slit 38. Ink droplets and dirt adhering to the surface are sucked, and air around the slit 39 is sucked into the second sucking member 37 from the slit 39 of the second sucking member 37, so that the head substrate at a position facing the slit 39. Ink droplets and dirt (adhered matter) adhering to the ejection surface 13 are sucked. This point will be described in detail later.

  The ink trap mechanism 46 is disposed in a tube 45 between the first suction member 36 and the second suction member 37 and the suction pump 48. The ink trap mechanism 46 removes foreign matters such as ink and dust that are sucked from the slits 38 and 39 and mixed in the air passing through the tube 45 when the suction pump 48 sucks air, and sucks the ink. Foreign matter is prevented from adhering to and mixed into the pump 48.

  The support 42 has a box shape with one surface open, and supports the first suction member 36 and the second suction member 37 therein. More specifically, the support body 42 has a shape that covers the surface excluding the surface on which the slit 38 of the first suction member 36 and the slit 39 of the second suction member 37 are formed, and the first suction member 36 and the first suction member 36. Two suction members 37 are supported. Further, the support 42 is formed with openings at portions corresponding to the connecting pipes 40 and 41.

Next, the removal mechanism moving unit 34 includes a support base 50, a drive screw 52, a guide rail 54, and a coupling body 56. The first suction member 36, the second suction member 37, and the support body 42 are attached to the head substrate. It moves to the direction (arrow Y direction in FIG. 6) orthogonal to 13 discharge surfaces.
That is, the removal mechanism moving unit 34 moves the first suction member 36 and the second suction member 37 from a standby position separated from the ejection surface of the head substrate 13 to a position close to the head substrate 13.

The support base 50 is fixed at a predetermined position such as a housing (not shown).
The drive screw 52 is a ball screw having a male screw portion, and is rotatably supported by the support base 50 in a direction in which a direction orthogonal to the ejection surface of the head substrate 13 is an axial direction.
The drive screw 52 is rotated by a drive unit (not shown) disposed inside the support base 50.
The guide rail 54 is disposed on the support base 50 adjacent to the drive screw 52 and parallel to the drive screw 52.
The connection body 56 is joined to the support body 42 by a fixing member such as a bolt screw or an adhesive. The coupling body 56 has a female screw portion and a hole portion, and a drive screw 52 is screwed into the female screw portion, and a guide rail 54 is passed through the hole portion.
The coupling body 56 is moved in a direction orthogonal to the ejection surface as the drive screw 52 rotates. Moreover, since the guide rail 54 is penetrated, the coupling body 56 is moved without changing the direction.

The removal mechanism moving unit 34 rotates the drive screw 52 to move the coupling body 56 in a direction orthogonal to the ejection surface of the head substrate 13. By moving the coupling body in this manner, the first suction member 36 and the second suction member 37 supported by the support body 42 and the support body 42 are also moved in a direction orthogonal to the ejection surface of the head substrate 13. The
In this way, the removal mechanism moving unit 34 can bring the first suction member 36 and the second suction member 37 into contact with the discharge unit 12. That is, the distance between the slit 38 of the first suction member 36 and the slit 39 of the second suction member 37 and the discharge port 16a of the discharge unit 12 can be adjusted.
By moving the first suction member 36 and the second suction member 37 in this way, the suction member 36 and the second suction member 37 are brought close to the recording head 136K when the maintenance device 30 is used, and when the maintenance device 30 is not used, By separating the suction member 36 from the recording head 136, specifically, by separating the suction member 36 from the recording head 136 with respect to the transport path of the recording medium P, the maintenance device 30 causes the recording medium P of the recording medium P at the time of label production. It is possible to prevent the conveyance and the image drawing on the recording medium P from being affected, that is, the trouble of the conveyance of the recording medium P and the image drawing on the recording medium P.
In this embodiment, the removal mechanism is moved using a drive screw or the like, but the moving means is not particularly limited, and for example, an air cylinder mechanism, a direct mechanism, or the like can be used.

Next, the ink pressurizing mechanism 64 is a pressurizing unit such as a compression pump, and is disposed in the supply pipe 61 that supplies ink to each ejection unit 12 of the recording head 136a.
The ink pressurization mechanism 64 pressurizes the ink in the supply pipe 61, thereby discharging the ink from the ejection ports 16a of the ejection units 12 of the recording head 136K.

The electromagnetic valve 66 is disposed upstream of the ink pressurizing mechanism 64 of the supply pipe 61 in the ink flow direction. That is, the electromagnetic valve 66 is disposed in the supply pipe 61 between the ink tank 60 and the ink pressurizing mechanism 64.
In this way, the solenoid valve 66 is provided in the supply pipe 61, and the ink in the supply pipe 61 is sealed in the ink tank 60 by sealing the supply pipe 61 when the ink in the supply pipe 61 is pressurized by the ink pressurizing mechanism 64. Backflow can be prevented.
Thereby, a desired amount of ink droplets can be discharged from the ejection port 16a.
The solenoid valve is not limited to this embodiment. For example, the electromagnetic valve is a three-way valve and is provided at the connecting portion between the supply pipe 61 and the ink pressurizing mechanism 64. If necessary, the recording head 136K and the ink pressurizing mechanism 64 communicate with each other, and It is also possible to switch between the state where the ink pad 136K and the ink tank 60 are in communication.
The digital label printing apparatus 100 is basically configured as described above.

Next, a method for creating a label by the digital label printing apparatus 100 will be described.
Here, FIGS. 8A to 8C are cross-sectional views showing a state in which ink droplets are ejected onto the surface of the undercoat liquid, respectively, and FIG. 9A is a recording target with irregularities on the image surface. FIG. 9B is a cross-sectional view showing the main part of the recording medium pressed with foil without smoothing, and FIG. 9C is a cross-sectional view showing the main part of the medium. It is sectional drawing which shows the principal part of the recording medium which smoothed the unevenness | corrugation and pressed the foil.
As shown in FIG. 1, the recording medium P sent out from a supply roll 122 wound in a roll shape is transported to the undercoat section 111 by a transport section 110 (a pair of transport rollers 124 and 126).

The recording medium P transported to the undercoat part 111 by the transport part 110 comes into contact with the application roll 190 of the undercoat part 111, and an undercoat liquid is applied to the surface to form an undercoat layer U.
Here, the application roll 190 is rotated in the direction opposite to the conveyance direction of the recording medium P by the drive unit 191. That is, the drive unit 191 moves the coating roll 190 in a direction in which the moving direction of the surface of the coating roll 190 and the moving direction of the recording medium P are opposite to each other at the contact position between the coating roll 190 and the recording medium P. It is rotating.

The recording medium P on which the undercoat liquid is applied and the undercoat layer U is formed is further transported by the transport roll pairs 124 and 126 of the transport section 110 and passes through a position facing the undercoat liquid semi-curing section 197.
The undercoat liquid semi-curing unit 197 irradiates the recording medium P coated with the undercoat liquid that passes through the opposing position, and semi-cures the undercoat layer U on the recording medium P.

Here, the state in which the undercoat liquid and / or ink droplets are semi-cured in the present invention (hereinafter also referred to as “semi-cured state”) means that the inside of the undercoat liquid and / or ink liquid is completely or partially cured. In addition, it means a state in which the degree of curing of the surface is lower than the degree of internal curing.
This semi-cured state is obtained after the semi-curing process of the undercoat liquid and / or ink droplets applied on the recording medium P (after irradiation with active energy rays or after heating, that is, in this embodiment, the undercoat liquid is used. After irradiating ultraviolet rays by the semi-cured portion 197 and / or the ultraviolet irradiating portion 138) and before the ink droplet is ejected in the next step, a penetrating medium such as plain paper is pressed to the undercoating liquid and / or the penetrating medium. This can be determined by whether or not the surface (part) of the ink droplet has been transferred.
That is, the case where the undercoat liquid and / or ink liquid is not transferred at all to the pressed permeation medium is assumed to be fully cured, the cured undercoat liquid and / or ink liquid remains on the recording medium, and the undercoat liquid is applied to the permeation medium. When a part of the ink liquid is transferred, it is assumed to be in a semi-cured state, that is, at least the outermost surface has fluidity and is internally cured.

In addition, when the semi-cured state of the undercoat liquid and / or ink droplet is realized by a polymerization reaction of a polymerizable compound that starts by irradiation with active energy rays or heating, the semi-cured state should be determined by infrared spectroscopic measurement. Is more preferable. Specifically, it is determined by measuring the polymerization rate from comparison of infrared absorption spectra before and after completion of the polymerization process of the undercoat liquid and / or ink droplets (for example, before and after irradiation of active energy rays and before and after heating). Is preferred.
Here, the polymerization rate is defined by the ratio of the infrared absorption peak intensity due to the polymerizable group detected by the infrared absorption spectrum, specifically, A (after polymerization) / A (before polymerization). A (after polymerization) is the absorbance of the infrared absorption peak due to the polymerizable group after the polymerization reaction, and A (before polymerization) is the absorbance of the infrared absorption peak due to the polymerizable group before the polymerization reaction. is there.

If A (after polymerization) / A (before polymerization) is 0.05 or more and 0.99 or less, it can be determined that the resin is in a semi-cured state.
Here, from the viewpoint of increasing the saturation of the image, A (after polymerization) / A (before polymerization) is preferably 0.1 or more and 0.98 or less, and is 0.15 or more and 0.97 or less. It is more preferable that it is 0.2 or more and 0.96 or less.

For example, when the polymerizable compound contained in the undercoat liquid and / or ink droplet is an acrylate monomer or a methacrylate monomer, an absorption peak based on a polymerizable group (acrylate group, methacrylate group) can be observed in the vicinity of 810 cm ⁻¹ . The polymerization rate is preferably defined by the absorption light intensity of the peak. When the polymerizable compound is an oxetane compound, an absorption peak based on the polymerizable group (oxetane ring) can be observed in the vicinity of 986 cm ⁻¹ , and the polymerization rate is preferably defined by the absorption light intensity of the peak. When the polymerizable compound is an epoxy compound, an absorption peak based on the polymerizable group (epoxy group) can be observed in the vicinity of 750 cm ⁻¹ , and the polymerization rate is preferably defined by the absorption light intensity of the peak.
As a means for measuring the infrared absorption spectrum, a commercially available infrared spectrophotometer can be used, which may be either a transmission type or a reflection type, and is preferably selected as appropriate in the form of a sample. For example, it can be measured using an infrared spectrophotometer FTS-6000 manufactured by BIO-RODO.

Further, a preferable semi-cured state of the undercoat liquid and / or the ink droplet is a primer liquid and / or an ink droplet after the semi-curing process of the undercoat liquid and / or the ejected ink droplet applied onto the recording medium P is completed. Alternatively, the determination can also be made by observing the cross section of the ink droplet that has been ejected onto the ink droplet.
Specifically, in the semi-cured undercoat liquid and / or ink droplet, in the cross section, a part of the ejected ink droplet is closer to the recording medium than the surface of the undercoat liquid and / or ink droplet. It is preferable to have a shape.
Here, in the present invention, the cross section of the ink droplet is defined as a cross section in which the area S of the cross section is the maximum in the cross section of the droplet obtained by cutting in a direction perpendicular to the surface of the recording medium. .
In the present invention, the liquid surface of the undercoat liquid and / or ink droplet is the liquid surface before the ink droplet is ejected.
The method for observing the cross section is not particularly limited, but can be observed using, for example, a commercially available microtome and a commercially available optical microscope.

Hereinafter, a case where ink droplets are ejected onto the surface of the undercoat liquid will be described in detail.
Here, FIGS. 8A to 8C are cross-sectional views showing a state where ink droplets are ejected onto the surface of the undercoat liquid (undercoat layer) U, respectively.
FIG. 8A is a cross-sectional view showing an example of a cross-sectional shape in which ink droplets are deposited on the surface of the semi-cured undercoat liquid. As shown in FIG. 8 (A), when ejecting ink droplets onto the undercoat liquid U is semi-cured, ink droplets d _a discharged onto the undercoat liquid U in its entirety undercoat liquid surface alpha (FIG. It becomes a state below the middle dotted line). That is, the entire ink droplet d _a is a state that sunk into the undercoat liquid U. As shown in FIG. 8A, the state in which the entire ink droplets have entered the liquid surface α of the undercoat liquid U is a preferable “semi-cured state”.
By curing the undercoat liquid so that the entire ink droplets are immersed in the liquid surface α of the undercoat liquid U, the ink droplets can be prevented from interfering with each other and an image with high saturation can be formed.

On the other hand, FIG. 8B is a cross-sectional view showing a cross-sectional shape when the undercoat liquid is excessively cured, that is, when the undercoat liquid is excessively cured. As shown in FIG. 8 (B), if it excessively curing the undercoating liquid U, the entire ink droplet d _b that is ejected onto the undercoating liquid U is above the liquid level α of the undercoating liquid U is there. That is, the entire ink droplet d _b are present on the undercoat liquid surface, in this case, can lead to deposition interference increases.

Next, FIG. 8C is a cross-sectional view showing another example of the cross-sectional shape when the undercoat liquid is properly cured, that is, when the undercoat liquid is in a suitable semi-cured state. Figure 8 (C), the ink droplet d _c is ejected onto the undercoating liquid U, it lies both above and below the undercoat liquid surface alpha. That is, a state in which a part of the ink droplets has entered the undercoat liquid is a state in which the undercoat liquid is preferably semi-cured. That is, a part of the ink droplet is on the undercoat liquid U (not shown recording medium P) side with respect to the undercoat liquid surface α. In this way, by curing the undercoat liquid so that a part of the ejected ink droplets may sink, it is possible to prevent the ink droplets from interfering with each other and to form an image with high saturation.

Here, when observing the cross section, it is preferable that the size of the ink droplet ejected onto the semi-cured undercoat liquid and / or ink liquid is 1 picoliter or more and 100 picoliter or less, and when actually recording an image. More preferably, the shape is equal to the size of the ink droplet to be ejected.
Further, it is preferable to solidify the semi-cured film, that is, the semi-cured undercoat liquid and / or ink liquid by some method during cross-sectional observation. The method for solidifying is not particularly limited, but freezing or curing by polymerization can be used.

From the viewpoint of achieving both avoidance and high image formation saturation deposition interference, as shown in FIG. 8 (C), in cross section, the area of the ink droplet d _c that is above the liquid surface of the undercoating liquid S ₁ and _(S (above the liquid level)), and the area of the ink droplet d _b below the liquid surface of the undercoating liquid and S _2, a value which is defined by S _{1 /} S ₂ from the liquid surface, 0 / It is preferably in the range of 100 to 95/5, more preferably in the range of 10/90 to 75/25, and particularly preferably in the range of 30/70 to 50/50. Incidentally, as shown in FIG. 8 (C), when the total cross-sectional area of the ink droplet d _c which is ejected onto the undercoating liquid in a semi-cured state and S (S (droplets)), S and S ₁ and S The relationship with ₂ is S−S ₁ = S ₂ .
The cross-sectional area can be measured by counting the number of pixels using commercially available image analysis software, for example, Adobe Photoshop.

  The recording medium P on which the undercoat layer is formed is transported to the drawing unit 112 by the transport roller pairs 124 and 126 of the transport unit 110.

The recording heads 136 </ b> Y, 136 </ b> C, 136 </ b> M, and 136 </ b> K eject ink droplets of ultraviolet curable ink to the recording medium P that passes through the opposing positions based on control by the control unit 121. The recording medium P on which the ink has been ejected is further conveyed, passes through a position facing the ultraviolet irradiation unit 138, is irradiated with ultraviolet rays, and the ink is semi-cured or cured.
That is, when the recording medium P passes through the positions facing the recording heads 136Y, 136C, and 136M, ink droplets are ejected from the recording heads 136Y, 136C, and 136M toward the recording medium P, and then the ultraviolet irradiation unit Ultraviolet rays are irradiated from 138, and each ink landed on the recording medium P is semi-cured. Further, when the recording medium P passes through a position facing the recording head 136K, ink droplets are ejected from the recording head 136K toward the recording medium P, and then ultraviolet rays are irradiated from the ultraviolet irradiation unit 138, All the ink and the undercoat liquid that have landed on the recording medium P are cured.
As a result, an image is formed on the surface of the recording medium P.

  The recording medium P on which the image has been recorded is transported to the smoothing unit 116 and is thickened by the varnish coater 142 so as to cover the entire image 184 formed on the recording medium P as shown in FIG. A transparent liquid 186 having a thickness of about 5 to 30 μm (dry film thickness) is applied.

  The recording medium P coated with the transparent liquid 186 is conveyed to a position facing the flat pressure member 146. The flat pressure member 146 moves in a direction approaching the recording medium P, and presses the recording medium P with a smooth surface 146a. By pressing the recording medium P with the smooth surface 146a, the ink on the recording medium P is crushed. Thereby, the ink (image) on the recording medium P becomes smooth. Here, the area of the smooth surface 146a of the flat pressure member 146 is larger than the foil supply range.

  The recording medium P with the smoothed image is conveyed to the foil pressing unit 118 via the conveyance buffer. The recording medium P conveyed to the foil pressing unit 118 is pressed by the hot stamp plate 160 through the foil 158. On the surface of the recording medium P pressed by the hot stamp plate 160, a foil 158 is heat-pressed on the surface according to the shape of the relief plate portion 160a of the hot stamp plate 160.

  The recording medium P to which the foil 158 has been heat-pressed, that is, pressed with foil, is conveyed to the label removing unit 120 and applied with an ultraviolet curable transparent liquid by the varnish coater 162, and then irradiated with ultraviolet rays by the ultraviolet irradiation unit 164. The applied UV curable transparent liquid is cured.

The recording medium P in which the ultraviolet curable transparent liquid is cured is conveyed to a die cutter 166, and a cut 180b is formed in the shape of the label L only on the adhesive sheet 180 by the cylinder cutter 168 and the receiving roller 170.
At this time, as described above, since the die cutter 166 makes the cut 180b having the shape of the label L while swinging intermittently, the cut 180b can be continuously formed, and the recording medium P is wasted. The part never occurs.
Thereafter, unnecessary portions other than the label L of the pressure-sensitive adhesive sheet 180 of the recording medium P are peeled off from the release paper 182 and taken up by the residue removing portion 172. The recording medium P in a state where only the label L is stuck on the release paper 182 is wound around the product winding unit 134 to become a product.
A label is created as described above.

  Here, as shown in FIG. 9A, the image surface of the recording medium P is three-dimensionally swelled by overlapping the cured inks 184 of multiple colors. The rise height of the ink varies depending on the ink absorbability of the recording medium P (the lower the absorbency, the higher the height), but it is about 10 μm per color, and when one multicolor ink is used. May be approximately 40 μm. The image surface of the recording medium P is uneven. This unevenness greatly affects the adhesion between the foil 158 and the recording medium P (more specifically, the ink 184 on the recording medium P) when foil-pressing the image surface of the recording medium P.

  That is, as shown in FIG. 9B, when foil pressing is performed on an image surface in which the foil donation range is not smoothed (in other words, the state where the ultraviolet curable ink is discharged and cured in the drawing unit 112), The foil 158 is heated and pressure-bonded only on the concave and convex peak portions, and is not pressed on the valley portions. That is, the degree of adhesion between the foil 158 and the recording medium P is low, and is easily peeled off.

  In contrast, in the present embodiment, the foil donation range is smoothed in advance by the flat pressure member 146 and then pressed onto the recording medium P. As a result, as shown in FIG. 9C, the foil 158 can be heat-bonded to a smooth surface with a wide area, and the foil pressing with high adhesion between the recording medium P and the foil 158 is difficult. it can.

That is, according to the digital label printing apparatus 100 of the present embodiment, smoothing is performed by using the flat pressure member 146 to smooth the ink 184 and the transparent liquid 186 in at least the foil donation range on the recording medium P upstream of the foil pressing unit 118. By disposing the portion 116, the foil 158 can be provided and pressed in the range smoothed by the smoothing portion 116.
Thereby, the adhesiveness of the recording medium P and the foil 158 can be improved, and favorable foil stamp printing can be performed. Moreover, since it is smoothed by the flat pressure member 146, it can be smoothed in a short time, and productivity can be improved.

  Further, a transparent liquid supply means (varnish coater) 142 for supplying the smoothing unit 116 with a transparent active energy ray curable liquid on the image surface on the recording medium P, and an active energy ray curable liquid (transparent liquid) after supply. ) Is provided with an active energy ray irradiating means (ultraviolet ray irradiating part) 148 for irradiating the active energy ray, and the image surface is covered with a transparent active energy ray curable liquid and smoothed so that the image surface has large irregularities. Even if it has, the foil donation range with favorable flatness can be formed.

  Furthermore, by using a varnish coater as the transparent liquid supply means, the transparent liquid 186 can be stably applied to the surface of the recording medium P on which the uneven image is formed with a simple and inexpensive mechanism.

  Here, the formation of the film of the ultraviolet curable transparent liquid by the varnish coater 162 and the ultraviolet irradiation unit 164 is not necessarily required because it is intended to give the image surface a gloss and obtain a high-quality image. When not required, it can be set not to form a film of an ultraviolet curable transparent liquid.

  In addition, by forming an undercoat layer on the recording medium, it is possible to prevent ink droplets that have landed on the recording medium from penetrating into the recording medium and causing blurring of the image, thereby forming a high-quality image. It becomes possible. It is also possible to use a recording medium that has low adhesion to ink droplets, that is, repels the landed ink droplets. In other words, it is possible to record images on various recording media.

In addition, as in the present embodiment, the undercoat layer is semi-cured by the undercoat solution semi-cured portion, so that even if the ink droplets overlap each other and land on the recording medium, the undercoat solution and the ink solution Due to the interaction of the droplets, coalescence between these adjacent ink droplets can be suppressed.
That is, by forming a semi-cured undercoat liquid layer on the recording medium, when the ink droplets ejected from the recording head land on the recording medium, for example, a single color ink droplet The ink droplets can be prevented from moving even when the ink droplets land on the recording medium with overlapping portions or when the ink droplets of different colors land on the recording medium with overlapping portions.
As a result, it is possible to effectively prevent the occurrence of blurring of the image, non-uniformity of the line width such as fine lines in the image and color unevenness of the colored surface, and sharp lines can be formed with a uniform width. For example, it is possible to record an inkjet image having a high droplet ejection density such as a fine line with good reproducibility. That is, a high-quality image can be formed on the recording medium.

Here, the viscosity (25 ° C.) of the semi-cured undercoat layer and / or the inner layer of the ink droplet is preferably 5000 mPa · s or more.
Further, the viscosity (25 ° C.) of the semi-cured undercoat layer and / or the surface layer of the ink droplet is preferably 100 mPa · s or more and 5000 mPa · s or less.
Further, the viscosity (25 ° C.) of the semi-cured undercoat layer and / or the inner layer of the ink droplet is 1.5 times or more of the viscosity (25 ° C.) of the semi-cured and / or ink droplet surface layer. Preferably, it is more preferably 2 times or more, and further preferably 3 times or more.
By setting it as the said range, an undercoat and / or an ink droplet can be semi-hardened suitably.

The polymerization degree of the polymerizable compound on the surface of the internally cured undercoat liquid (undercoat layer) and / or ink droplets is preferably 1% to 70%, and preferably 5% to 60%. More preferably, it is particularly preferably 10% or more and 50% or less. Here, the degree of polymerization can be measured by IR or the like.
By setting it as the said range, an undercoat can be semi-hardened suitably.

  Further, by applying the undercoat liquid onto the recording medium P by using the coating roll 190 and further rotating the coating roll 190 in the direction opposite to the conveying direction of the recording medium P, the surface of the recording medium P is covered. An undercoat layer U having an improved shape can be formed. That is, when the coating roll 190 is separated from the recording medium P after the coating roll 190 applies the undercoat liquid to the recording medium P by rotating the coating roll 190 in the direction opposite to the conveyance direction of the recording medium P. The surface of the undercoat liquid applied onto the recording medium P can be prevented from being disturbed, and the undercoat layer U having a smooth surface, that is, a small surface roughness can be formed on the recording medium P.

Next, maintenance of the ink jet head according to the fourth aspect of the present invention for removing droplets and dirt adhering to the ejection surfaces of the head substrate 13 of the recording heads 136Y, 136C, 136M, and 136K, particularly around the ejection port 16a. A method will be described.
The maintenance method of the ink jet head (recording head) is the same for all of the recording heads 136Y, 136C, 136M, and 136K, and therefore the case of the recording head 136K will be described as a representative.
FIGS. 10A and 10B are process diagrams for explaining a recording head maintenance method by the maintenance unit 114.

First, while the image is recorded by the recording head 136K, that is, while the label is being produced, the suction member 36 (and the removal mechanism 32 such as the support member) is used as shown in FIG. More specifically, it is waiting at a position that does not hinder the conveyance of the recording medium P.
When the production of the label by the label printing apparatus 100 is completed and maintenance of the recording head 136K is performed, first, the maintenance apparatus 30 uses the removal moving mechanism 34 to move the suction member 36 to the head as shown in FIG. The substrate 13 is moved toward the ejection surface, that is, the suction member 36 is moved to the recording head 136K side. That is, the slit 38 of the suction member 36 is brought close to the discharge port 16 a of the discharge unit 12. In other words, the slit 38a is moved to the discharge port 16a side to a position where it does not contact the discharge port 16a.

  Next, the maintenance device 30 sucks the air around the slits 38 and 39 by sucking the air inside the first suction member 36 and the second suction member 37 to a negative pressure by the suction pump 48.

  In this way, the air around the slits 38 and 39 is sucked from the slits 38 and 39 respectively disposed at both ends of the discharge port 16a with the slit 38 in a state of sucking air close to the discharge surface of the head substrate 13. As a result, ink droplets and dirt adhering to the periphery of the ejection port of the ejection surface of the head substrate 13 can be sucked and removed.

In this way, the slits 38 and 39 are respectively arranged at positions facing both ends of the discharge port 16a, and the ink (ink droplet) and dirt around the discharge port 16a are sucked and removed together with the air, thereby removing the discharge port. The ejection direction of the ink droplets ejected from 16a can be made constant. That is, it is possible to prevent the ink droplet landing positions from being displaced.
As a result, a high-quality image can be stably formed on the recording medium.

In addition, the slits 38 and 39 are disposed at positions opposite to both ends of the discharge port 16a and sucked, whereby the opening diameter of each slit can be reduced. That is, by disposing the slits at both ends, ink droplets and dirt (fixed matter) around the ejection port can be removed even with a slit having a small opening diameter.
Thus, an inexpensive pump can be used by reducing the opening diameter of the slit. Even when a pump with a small suction force is used, the suction force of air sucked from the slit can be increased by reducing the opening diameter of the slit. Furthermore, by increasing the suction force sucked from the slit, it is possible to more reliably suck ink droplets and fixed matter around the ejection port.

Also, by forming the slits of the suction members in a shape that is long in the arrangement direction of the discharge ports, that is, by forming a common slit in a plurality of discharge ports, the slits of one suction member form a line on the head substrate. Ink droplets and dirt adhering around the plurality of ejection openings formed at the same time can be sucked and removed simultaneously, and the recording head can be maintained in a short time.
In particular, as in this embodiment, the length of the suction members in the arrangement direction is the same as the length of the head substrate, that is, in this embodiment, the length of the suction members in the arrangement direction is arranged in a row. By setting the length so as to cover all the discharge ports arranged in the head, it is possible to maintain all the discharge ports formed in a line on the head substrate with one suction member at the same time. The recording head can be maintained without being moved in the arrangement direction.

  In addition, the ink droplets and solid matter adhering around the ejection port of the head substrate ejection surface can be removed without coming into contact with the ejection surface of the head substrate, thereby damaging the ejection surface of the head substrate. Can be prevented.

  As described above, according to the present embodiment, ink droplets and dirt around the ejection port can be sucked and removed efficiently in a short time, and the apparatus configuration can be simplified and the apparatus can be made inexpensive. can do.

The suction members (first suction member 36 and second suction member 37) preferably have a slit (a suction port described later) having a size of 1 mm or less in a direction orthogonal to the arrangement direction of the discharge ports.
The effect mentioned above can be acquired more suitably by making the magnitude | size of a slit into the shape which satisfies the said range.

  Here, in the present embodiment, since ink droplets and dirt attached around the discharge port on the discharge surface can be more efficiently removed, the slit 38 is opened in the direction perpendicular to the arrangement direction of the discharge ports 16a. Is disposed at a position sandwiching one end of the discharge port 16a, and the slit 39 is disposed at a position where the opening sandwiches the other end of the discharge port 16a. However, the present invention is not limited to this, and the discharge port 16a. It is only necessary that slits are arranged corresponding to the respective end portions, that is, it is only necessary that separate slits are formed at both ends of the discharge ports, for example, in a direction orthogonal to the arrangement direction of the discharge ports 16a, You may arrange | position in the position where the opening of each slit becomes an outer side rather than the edge part of a discharge outlet.

Further, the first suction member 36 and the second suction member 37 have an opening diameter of R [mm] and a size of the suction port in a direction orthogonal to the arrangement direction of the discharge ports L [mm]. Then, it is preferable to arrange | position in the position where the space | interval of the direction orthogonal to the sequence direction of the discharge port 16a of the slit 38 and the slit 39 satisfy | fills below (R + L + 2) [mm].
By setting the distance between the slit 38 and the slit 39 within the above range, ink droplets and dirt around the ejection port of the ejection surface of the head substrate can be removed in a shorter time and with certainty.

In the present embodiment, the first suction member 36 and the second suction member 37 are provided as the removing mechanism, and are separated from each other in a direction perpendicular to the arrangement direction of the discharge ports and formed in parallel to each other. The two slits having the arrangement direction as the longitudinal direction are formed. However, the present invention is not limited to this, and the arrangement direction of the discharge ports 16a formed in parallel to each other is separated in a direction perpendicular to the arrangement direction of the discharge ports. Various types of suction members in which two slits in the longitudinal direction are formed can be used.
For example, the suction member may have a shape having a branch pipe that separates the suction member into two, a slit may be formed in each branch pipe, and the surface facing the discharge surface of the head substrate is a wide surface, and the arrangement of the discharge ports 16a It is good also as a structure which formed two slits spaced apart by the predetermined distance in the direction orthogonal to a direction.

Next, another example of the recording head maintenance method will be described.
FIGS. 11A to 11E are process diagrams for explaining another example of the print head maintenance method.

  At the start of the maintenance, as shown in FIG. 11A, ink droplets or the like are attached around the ejection openings 16a on the ejection surface of the head substrate 13 of the recording head 136K.

  From this state, first, as shown in FIG. 11B, the ink in the supply pipe 61 is pressurized from the ink pressurizing mechanism 64, and the ink droplets are discharged from all the ejection ports 16a of the recording head 136K. At this time, the valve of the electromagnetic valve 66 is closed to seal the supply pipe 61. Thereby, when the ink in the air supply pipe 61 is pressurized by the ink pressurizing mechanism 64, the ink in the supply pipe 61 is prevented from flowing back into the ink tank 60.

  By discharging the ink from all the ejection ports 16a of the recording head 136K, as shown in FIG. 11C, the ink is adhered to the entire ejection surface of the head substrate 13, that is, the ink is wet (ink Painted).

Thereafter, as shown in FIG. 11D, ink droplets and dirt adhering to the ejection surface of the head substrate 13 are sucked by the maintenance device 30 in the same manner as described above.
Specifically, the slit is brought close to the ejection port, the slit in a state of sucking air is moved, and ink droplets and dirt adhering to the ejection surface of the head substrate 13 are sucked.

  By sucking ink droplets and dirt adhering to the ejection surface of the head substrate 13 by the maintenance device 30, the ink droplets and dirt adhere to the ejection surface of the head substrate 13 as shown in FIG. Not in a state.

As described above, the ink pressurization mechanism discharges ink droplets from the discharge ports and wets the discharge surface of the head substrate 13 with the ink, whereby the ink droplets can be easily sucked.
Further, the dirt attached around the discharge port on the discharge surface of the head substrate 13 can be removed together with the discharge of the ink from the discharge port, and the stain (attachment) is easily sucked by wetting with the ink. be able to.

  As described above, according to the present embodiment, ink droplets and dirt (attachments) attached to the ejection surface of the head substrate 13 can be more easily sucked and adhered to the ejection surface of the head substrate 13. Ink droplets and dirt can be removed more reliably.

Here, when discharging ink from the ejection port, it is preferable to arrange a plate-shaped liquid flow guide 70 at a position facing the ejection surface of the head substrate 13 as shown in FIG.
In this manner, the liquid flow guide 70 is disposed at a position facing the discharge surface of the head substrate 13, and a flow path for the ink discharged from the discharge ports is formed between the discharge surface of the head substrate 13 and the liquid flow guide. can do.
Thus, by disposing the liquid flow guide 70, the ejection surface of the head substrate 13 can be more easily wetted with a small amount of ink.
Further, the ink (flowing material) flowing through the flow path formed between the ejection surface of the head substrate 13 and the liquid flow guide 70 is in a state in which dirt (attachment) attached to the ejection surface of the head substrate 13 can be easily sucked. Or it can be washed away, and it becomes possible to remove the dirt (attachment) adhering to the ejection surface more reliably.
The liquid flow guide 70 may be disposed at a position facing the discharge port on the discharge surface of the head substrate only when in use by a moving mechanism (not shown).

  In this embodiment, the ink in the supply pipe 61 is pressurized by the ink pressurizing mechanism 64 to discharge the ink from the discharge port 16a. However, the method of attaching the ink to the discharge surface of the head substrate 13 is not limited to this. The ink droplets may be continuously ejected by driving the actuators 24 of all the ejection units 12 in the same manner as the normal recording operation, and each ejection from the ink tank by the pressurizing means. Ink may be supplied to the portion and discharged from each discharge port.

Next, FIG. 13 is a schematic configuration diagram showing another example of the maintenance apparatus of the present invention.
Since the maintenance device 202 shown in FIG. 13 has the same configuration as the maintenance device 30 shown in FIG. 6 except for the configuration of the removal mechanism 204, the same parts are denoted by the same reference numerals. Thus, the description thereof will be omitted, and the points peculiar to the maintenance device 204 will be mainly described below.

The maintenance device 202 includes a removal mechanism 204 and a removal mechanism moving unit 34.
The removal mechanism 204 includes the suction member 36, the support 42, the ink trap mechanism 46, the suction pump 48, the blowing member 206, and the blowing pump 214. Since the support 42, the ink trap mechanism 46, and the suction pump 48 have the same configuration as the maintenance device 30 described above, detailed description thereof is omitted. The removal mechanism 204, the removal mechanism moving means 34, the ink pressurizing mechanism 64, and the electromagnetic valve 66 are connected to the control unit 121 (see FIG. 1), and various operations are controlled by the control unit 121. Is the same.

  The suction member 36 is disposed so as to face the ejection unit 12 of the recording head 136K, and has a hollow box shape whose width decreases toward the ejection unit 12 side. Since the suction member 36 has the same shape and configuration as the first suction member 36, a detailed description thereof will be omitted.

The blowing member 206 is disposed at a predetermined interval in the direction perpendicular to the arrangement direction of the discharge ports 16 a with respect to the suction member 36. The blowing member 206 has a shape symmetrical to the suction member 36 with a surface parallel to the arrangement direction of the discharge ports 16a and perpendicular to the discharge surface of the head substrate 13 as an axis. In other words, the blowing member 206 is disposed so as to face the ejection portion 12 (ejection surface of the head substrate 13) of the recording head 136K, and a hollow portion whose width becomes smaller as a part of the ejection portion 12 side moves toward the ejection portion 12 side. It is a box shape.
Further, the blowing member 206 has a slit 208 formed at the tip on the discharge unit 12 side, and a connecting pipe 210 is provided on a part of the surface opposite to the surface on which the slit 208 is formed (opposing surface). It has been.

Here, the slit 38 of the suction member 36 is disposed at a position facing one end of the discharge port 16a in the direction orthogonal to the arrangement direction of the discharge ports 16a, and the slit 208 of the blowing member 206 is formed of the discharge port 16a. Is disposed at a position facing the other end of the discharge port 16a in a direction orthogonal to the arrangement direction. That is, the two slits 38 and 208 are respectively arranged to face both end portions of the discharge port 16a. That is, the slit 38 is disposed at a position where the opening sandwiches one end portion of the discharge port 16a, and the slit 208 is disposed at a position where the opening sandwiches the other end portion of the discharge portion 16a.
In addition, the suction member 36 and the blowing member 206 are also connected to the connecting pipe 40 and the tube 212, which are partially connected to the tube 45 in the cross-sectional shape at an arbitrary position in the longitudinal direction of the recording head 136 </ b> K, that is, the arrangement direction of the discharge ports 16 a. The connecting pipe 210 is substantially the same shape except that the connecting pipe 210 is formed. That is, the slit 38 and the slit 208 are disposed to face the plurality of discharge ports 16a arranged in a row. That is, one slit 38 and one slit 208 are arranged to face the plurality of ejection openings 16a.

Both ends of the tube 45a are connected to the suction member 36 and the suction pump 48, respectively. That is, the tube 45a allows the suction member 36 and the suction pump 48 to communicate with each other.
The suction pump 48 sucks air in the suction member 36 through the tube 45a, and makes the inside of the suction member 36 have a negative pressure.

  In addition, the blowing member 206 is connected to the blowing pump 214 via the tube 212. More specifically, the tube 212 has one end connected to the connection pipe 210 of the blowing member 206 and the other end connected to the blowing pump 214. Thus, the blowing member 206 and the blowing pump 214 are communicated with each other by the tube 212.

  The blowing pump 214 is a pump that supplies air such as a compression pump and an air pump, and supplies air to the blowing member 206 via the tube 212.

The removal mechanism 204 has such a configuration, and when air is supplied from the blowing pump 214 to the blowing member 206, air is blown out from the slit 208 of the blowing member 206.
Here, the slit 206 of the blowing member 206 is formed on a surface facing the ejection surface of the head substrate 13. Therefore, the air blown from the slit 208 of the blowing member 206 is blown to the ejection surface of the head substrate 13.
On the other hand, like the first suction member 36 described above, the suction member 36 sucks air around the slit 38 from the slit 38 into the suction member 36 and adheres to the ejection surface of the head substrate 13 at a position facing the slit 38. Sucked ink droplets and dirt.
That is, the removing mechanism 204 blows air around the discharge port 16 a formed on the discharge surface of the head substrate 13 from the slit 208 of the blowing member 206, and from the slit 38 of the suction member 36 disposed adjacent to the blowing member 206. By sucking air around the discharge port 16a, ink droplets and dirt (attachment) adhering around the discharge port 16a on the discharge surface of the head substrate 13 are sucked.

In this way, ink droplets and dirt adhering around the ejection port on the ejection surface of the head substrate can also be removed by blowing air around the ejection port on the ejection surface of the head substrate. Can do.
In addition, by blowing air around the ejection openings on the ejection surface of the head substrate, ink droplets and dirt can be more reliably removed from around the ejection openings. Further, air around the ejection openings on the ejection surface of the head substrate can be removed. By sucking the ink droplets, it is possible to prevent ink droplets and dirt from scattering to other parts.

  Here, also in the present embodiment, ink droplets and dirt adhering to the periphery of the ejection port on the ejection surface can be more efficiently removed. Therefore, the slit 38 is opened in the direction orthogonal to the arrangement direction of the ejection ports 16a. Is disposed at a position sandwiching one end of the discharge port 16a, and the slit 208 is disposed at a position where the opening sandwiches the other end of the discharge port 16a. However, the present invention is not limited to this, and the discharge port 16a. It is only necessary that slits are disposed opposite to the respective end portions of the nozzles, and it is only necessary that separate slits are formed at both ends of the discharge ports. For example, in the direction orthogonal to the arrangement direction of the discharge ports 16a, You may arrange | position in the position where the opening of a slit becomes an outer side rather than the edge part of a discharge outlet.

Moreover, it is preferable that the size of the slit in the direction orthogonal to the arrangement direction of the discharge ports be the same size as the slit of the suction member.
By setting the size of the slit of the blowing member to the same size as the slit of the suction member, air can be efficiently blown onto the head substrate, and the above-described effects can be obtained more suitably.

Further, the blowing member 206 is orthogonal to the arrangement direction of the discharge ports 16a, where R [mm] is the opening diameter of the discharge ports and L [mm] is the size of the outlet in the direction orthogonal to the arrangement direction of the discharge ports. It is preferable that the gap between the slit 208 and the slit 38 in the direction to be arranged is a position satisfying (R + L + 2) [mm] or less.
By setting the distance between the slit 38 and the slit 208 within the above range, ink droplets and dirt around the ejection port of the ejection surface of the head substrate can be reliably removed in a shorter time.

FIG. 14 is a partial cross-sectional view illustrating a schematic configuration of another example of the maintenance device.
The maintenance device 220 shown in FIG. 14 has the same configuration as the maintenance device 30 shown in FIG. 6 except for the configuration of the removal mechanism 222. Therefore, the same parts are denoted by the same reference numerals. Thus, the description thereof will be omitted, and the points peculiar to the maintenance device 220 will be mainly described below.

The maintenance device 220 includes a removal mechanism 222 and a removal mechanism moving unit 34.
The removal mechanism 222 includes a first suction member 36, a second suction member 37, a support 42, an ink trap mechanism 46, a suction pump 48, a blowing member 224, and a blowing pump 214. Since the first suction member 36, the second suction member 37, the support 42, the ink trap mechanism 46, and the suction pump 48 have the same configuration as the maintenance device 30 described above, a detailed description thereof will be given. Omitted.
The removal mechanism 222, the removal mechanism moving unit 34, the ink pressurizing mechanism 64, and the electromagnetic valve 66 are connected to the control unit 121 (see FIG. 1), and various operations are controlled by the control unit 121. Is the same.
In addition, the first suction member 36 and the second suction member 37 have the same configuration, function, and the like, but the arrangement interval between the first suction member 36 and the second suction member 37 shown in the maintenance device 30 is the same. It is arranged wider than the arrangement interval.

The blowing member 224 is disposed between the first suction member 36 and the second suction member 37, that is, disposed at a position facing the center of the discharge port.
The blowout member 224 is disposed to face the ejection unit 12 (ejection surface of the head substrate 13) of the recording head 136K, and has a hollow box shape whose width decreases as a part of the ejection unit 12 side moves toward the ejection unit 12 side. Shape.
Further, the blowing member 224 has a slit 226 formed at the tip on the discharge unit 12 side, and a connecting pipe 228 is provided on a part of the surface opposite to the surface on which the slit 226 is formed (opposite surface). It has been.
Here, the blowing member 224 is also substantially the same in cross-sectional shape at an arbitrary position in the longitudinal direction of the recording head 136K, that is, in the arrangement direction of the discharge ports 16a, except that the connecting pipe 228 connected to the tube 212 is formed. Shape. That is, the slits 226 are arranged to face the plurality of ejection ports 16a arranged in a row. That is, one slit 228 is disposed to face each of the plurality of discharge ports 16a.
In addition, a blow pump 214 is connected to the blow member 224 via a tube 212 in the same manner as the blow member 206 of the maintenance device 202 described above.

The removal mechanism 222 has such a configuration, and when air is supplied from the blow pump 214 to the blow member 224, air is blown from the slit 226 of the blow member 224. The air blown out from the slit 226 of the blowing member 224 is blown onto the surface facing the ejection surface of the head substrate 13.
On the other hand, the first suction member 36 and the second suction member 37 suck the air around the slit 38 and the slit 39 from the slit 38 and the slit 39 into the first suction member 36 and the second suction member 37. Ink droplets and dirt adhering to the ejection surface of the head substrate 13 at a position facing the slit 39 are sucked.

  That is, the removal mechanism 222 blows air from the slit 226 of the blowing member 224 to the periphery of the discharge port 16a formed on the discharge surface of the head substrate 13, and both sides in the direction orthogonal to the arrangement direction of the discharge ports 16a of the blow member 224. The air around the discharge port 16a is sucked from the slit 38 of the first suction member 36 and the slit 39 of the second suction member 37 that are arranged adjacent to each other, so that the periphery of the discharge port 16a on the discharge surface of the head substrate 13 Ink droplets and dirt (adhered matter) adhering to the ink are sucked.

As shown in the maintenance device 220, the blowing member 224 is disposed between the first suction member 36 and the second suction member 37, and air is blown from the center toward the discharge port 16a of the discharge surface of the head substrate 13, By suctioning from both sides to the periphery of the ejection port 16a on the ejection surface of the head substrate 13, ink droplets and dirt attached around the ejection port 16a on the ejection surface of the head substrate 13 can be removed.
A slit 38 of the first suction member 36 and a slit 39 of the second suction member 37 for sucking air and / or ink (ink adhering to the ejection surface) are provided on both side surfaces of the slit 226 of the blowing member 224 for blowing air. By disposing the air droplets on the ejection surface of the head substrate 13, it is possible to more reliably prevent the ink droplets and dirt removed from the ejection surface from scattering.

  Note that the size of the opening of the slit and the preferable positional relationship between the first suction member 36 and the second suction member 37 are the same as those in the maintenance device 30 described above, and detailed description thereof is omitted.

Here, in the present embodiment, before the air and / or ink is sucked from the suction port, that is, when the suction pump is stopped, the suction member of the removal mechanism, or the suction member and the blowing member (removal) is removed by the removal mechanism moving unit. By moving the mechanism) in the direction perpendicular to the ejection surface of the head substrate, a slit is placed near the ejection surface of the head substrate. In other words, the suction port or the distance between the suction port and the outlet and the ejection surface is constant. Although the distance is equal to or less than the distance, instead of this, the removal mechanism may be moved parallel to the ejection surface of the head substrate and parallel to the arrangement direction of the ejection ports.
That is, as shown in FIGS. 15A and 15B, the standby position of the removal mechanism is a position separated from the position facing the ejection surface of the head substrate by a predetermined distance in a direction parallel to the arrangement direction of the ejection ports, Specifically, it is located outside the width direction of the transport path of the recording medium P, and the removal mechanism moving mechanism moves the removal mechanism from the standby position (solid line in FIG. 15A) to the head substrate (FIG. 15 ( A) may be moved to the middle dotted line).
Here, although not shown in FIGS. 15A and 15B, the moving mechanism that moves the removal mechanism in a direction parallel to the arrangement direction of the discharge ports is not particularly limited. For example, the suction member (removal mechanism) In the same manner as in the method of moving the head) in the direction perpendicular to the ejection surface of the head substrate, various moving means such as a method using a ball screw, linear driving, and belt conveyance can be used.
As described above, the moving device can also be moved by setting the standby position of the removal mechanism to the outside of the transport path of the recording medium and moving the maintenance device parallel to the ejection surface of the head substrate and parallel to the arrangement direction of the ejection ports. Although the size of the apparatus is increased and the entire apparatus becomes larger, the maintenance apparatus can be prevented from obstructing the conveyance of the recording medium P during image recording.

  Here, as shown in FIGS. 15A and 15B, when the standby position of the removal mechanism is outside the transport path of the recording medium P, the removal mechanism is held at the standby position during image recording. Then, at the start of maintenance, the removal mechanism is moved from the standby position (solid line in FIG. 15A) to the position facing the head substrate (dotted line in FIG. 15A) by the removal mechanism moving mechanism. Subsequent operations are the same as the maintenance method described above.

  In each of the above embodiments, the recording head of the drawing unit is a full-line head type in which the ejection ports (ejection units) are arranged in a line in a line. As shown, the recording heads 640 may have a configuration in which a plurality of rows of ejection openings (ejection sections) are arranged in a staggered manner with a certain pitch shift. In this manner, by arranging the ejection ports (ejection units 12) in a staggered manner and forming one row of droplet ejection points with a plurality of rows of ejection units, it is possible to form an image with higher resolution.

  Here, as shown in FIG. 16, when the ejection portions of the recording head are arranged two-dimensionally, that is, in a matrix arrangement, a maintenance device may be provided for each row of ejection portions of the recording head. A moving mechanism for moving in the direction perpendicular to the arrangement direction of the discharge units), that is, in the row direction is provided, and one maintenance device is moved in the row direction so that the discharge surface of the head substrate of the recording head having a plurality of columns of discharge units Ink droplets and dirt around the ejection port may be sucked and removed.

  Further, in this embodiment, since maintenance can be performed in a short time, the maintenance device is arranged for each recording head, but the present invention is not limited thereto, and the maintenance device is provided with a moving mechanism that moves between the recording heads. One maintenance device may perform maintenance of a plurality of recording heads, that is, remove ink droplets and stains attached around the ejection openings on the ejection surface of the head substrate. Thus, by using one maintenance device, the device configuration can be simplified and the device can be made inexpensive.

In the present embodiment, one slit corresponding to all the discharge ports arranged in a row is formed as the suction port of the suction member. However, the present invention is not limited to this, and the slit is divided into a plurality of shapes. It may be a suction port. For example, a suction port may be provided for each of the ejection ports arranged in a row so that ink droplets and dirt attached around the respective ejection portions of the ejection surface of the head substrate may be sucked.
Moreover, although the one outlet corresponding to all the ejection openings arrange | positioned at row | line | column also formed the blower outlet of the blowing member, it is not limited to this similarly, It is good also as a blower outlet of the shape which divided | segmented the slit into plurality. . For example, an outlet may be provided for each outlet arranged in a row, and air may be blown around each outlet on the outlet surface of the head substrate.

The suction port of the suction member is preferably divided in a direction orthogonal to the arrangement direction of the discharge portions. That is, it is preferable to arrange the partition plate in the discharge port of the suction member in a direction parallel to the arrangement direction.
In this way, by dividing the suction port in a direction perpendicular to the arrangement direction of the ejection unit, even if a part of the suction port is clogged with ink droplets and dirt during suction, the ink droplets, Dirt can be aspirated. As a result, ink droplets and dirt around the ejection port can be removed more reliably.

Next, another example of the digital label printing apparatus will be described with reference to FIG.
The digital label printing apparatus 101 shown in FIG. 17 has the same configuration as the digital label printing apparatus 100 shown in FIG. 1 except for the position of the buffer. Accordingly, the same reference numerals are given to the same components in both, and the detailed description thereof will be omitted, and the points peculiar to the digital label printing apparatus 101 will be mainly described below.
In the digital label printing apparatus 101 illustrated in FIG. 17, a buffer is disposed between the drawing unit 112 and the smoothing unit 116. Thus, the position of the transport buffer is not particularly limited, and can be various ones.

  In this embodiment, the active energy ray curable ink is used as the ink, the active energy ray curable ink is ejected from the recording head, and an image of the active energy ray curable ink is formed on the recording medium P. The digital label printing apparatus has been described as irradiating an active light beam, curing the image, and fixing the image on the recording medium. However, the present invention is not limited to this, and the recording is performed on the recording medium P, for example. An ink jet recording apparatus that fixes the image on the recording medium P by heating and pressurizing the image can be used.

  The configuration of the recording head is not limited to the above-described embodiment, and various structures can be used. For example, a recording head using a so-called side shoot method or another top shooter recording head may be used. In this embodiment, the ink droplets are ejected by deformation of an actuator represented by a piezo element (piezoelectric element). However, the present invention is not limited to this, and a heating element such as a heater is used instead of the piezo system. A recording head using a method of discharging various inks such as a thermal jet method in which ink is heated to generate bubbles and the ink droplets are ejected by the pressure can be used.

In this embodiment, since an effect such as formation of a higher quality image can be obtained, an undercoat portion is provided, and an undercoat liquid is applied onto the recording medium before the image is formed by the drawing portion. Although the undercoat layer is formed, the undercoat portion is not necessarily provided, and an image may be formed in the drawing portion without forming the undercoat layer on the recording medium.
In addition, since the undercoat liquid can be applied more uniformly, it is preferable to apply by rotating the application roll in the reverse direction as in this embodiment, but the application method of the undercoat liquid is not particularly limited, and spray application, Various methods such as coating using an ink jet recording method can be used.

In the above-described embodiments, the maintenance device (device) is arranged in the digital label printing device. However, the maintenance device may be an independent device that can be attached to and detached from the inkjet head.
Further, the maintenance device can be an ink jet head as a single unit, that is, an ink jet head having a maintenance device.
Further, like the digital label printing apparatus of the present embodiment, an inkjet recording apparatus having at least an inkjet head and a maintenance device can be provided.

  In the above-described embodiment, the present invention has been described as being used in a digital label printing apparatus. However, the present invention is not limited to this, and can be applied to various recording media such as ordinary people, metals, resin materials, and the like by an inkjet recording method. It can be used as an apparatus for recording an image, for example, a maintenance apparatus such as a printer or a plate making apparatus, or a maintenance method.

  Hereinafter, the recording medium, the undercoat liquid and the ink which can be suitably used for the ink jet recording apparatus of the present invention, particularly the undercoat liquid and the ink which can be suitably used for semi-curing will be described.

(Physical properties of ink and undercoat liquid)
Here, the physical properties of the ink (droplet) ejected onto the recording medium vary depending on the apparatus, but generally the viscosity at 25 ° C. is preferably 5 to 100 mPa · s, and 10 to 80 mPa · s. It is more preferable that The viscosity (25 ° C.) of the undercoat liquid before internal curing is preferably 10 to 500 mPa · s, and more preferably 50 to 300 mPa · s.

In the present invention, from the viewpoint of forming dots of a desired size on the recording medium, the undercoat liquid preferably contains a surfactant, and the following conditions (A), (B) and (C) It is more preferable to satisfy all of the above.
(A) The surface tension of the undercoat liquid is smaller than the surface tension of any ink ejected onto the recording medium.
(B) At least one of the surfactants contained in the undercoat liquid is
γs (0) −γs (saturation)> 0 (mN / m)
Satisfy the relationship.
(C) The surface tension of the undercoat liquid is
γs <(γs (0) + γs (saturation) ^maximum ) / 2
Satisfy the relationship.

Here, γs is the value of the surface tension of the undercoat liquid. γs (0) is the value of the surface tension of the liquid excluding all surfactants in the composition of the undercoat liquid. γs (saturation) is obtained when one surfactant among the surfactants contained in the undercoat liquid is added to the “liquid excluding all surfactants” and the concentration of the surfactant is increased. The surface tension value of the liquid with the surface tension saturated. The γs (saturation) ^maximum is the maximum value of γs (saturation) obtained for all surfactants satisfying the condition (B) among the surfactants contained in the undercoat liquid.

<Condition (A)>
In the present invention, as described above, in order to form an ink dot of a desired size on a recording medium, it is preferable to make the surface tension γs of the undercoat liquid smaller than the surface tension γk of any ink. .
Further, from the viewpoint of more effectively preventing the expansion of ink dots from landing to exposure, it is more preferable that γs <γk-3 (mN / m), and γs <γk-5 (mN / m). It is particularly preferred that
In the case of forming (printing or drawing) a full-color image, from the viewpoint of improving the sharpness of the image, the surface tension γs of the undercoat liquid is at least higher than the surface tension of the ink containing a colorant having high visibility. It is preferable to make it smaller, and it is more preferred to make it smaller than the surface tension of all inks. Examples of the colorant with high visibility include colorants exhibiting magenta, black, and cyan colors.
Further, from the viewpoint of proper discharge, the surface tension γk of the ink and the surface tension γs of the undercoat liquid satisfy the above-described relationship between the surface tension γk of the ink and the surface tension γs of the undercoat liquid, and each 15 mN / m. It is preferably in the range of 50 mN / m or less, more preferably in the range of 18 mN / m or more and 40 mN / m or less, and particularly preferably in the range of 20 mN / m or more and 38 mN / m or less.
By setting both values to 15 mN / m or more, it is possible to suitably form droplets at the time of droplet ejection by the inkjet head, and it is possible to prevent non-ejection. That is, ink droplets can be suitably discharged. Moreover, by setting it as 50 mN / m or less, wettability with an inkjet head can be made high and an ink droplet can be discharged suitably. That is, it is possible to prevent non-ejection of droplets. By setting both values within the range of 18 mN / m or more and 40 mN / m or less, and further within the range of 20 mN / m or more and 38 mN / m or less, the above effects can be obtained more suitably, and ink droplets can be obtained. Can be reliably discharged.
Here, in the present embodiment, the surface tension is measured by a Wilhelmy method using a commonly used surface tension meter (for example, Kyowa Interface Science Co., Ltd., surface tension meter CBVP-Z). The value measured at 60% RH.

<Condition (B) and Condition (C)>
In the present invention, the undercoat liquid preferably contains at least one kind of surfactant. By containing at least one type of surfactant in the undercoat liquid, it is possible to more reliably form ink dots of a desired size on the recording medium. In this case, at least one of the surfactants contained in the undercoat liquid preferably satisfies the following condition (B).
γs (0) −γs (saturation)> 0 (mN / m) Condition (B)
Furthermore, the surface tension of the undercoat liquid preferably satisfies the relationship of the following condition (C).
γs <(γs (0) + γs (saturation) ^maximum ) / 2 ... condition (C)

As described above, γs is the value of the surface tension of the undercoat liquid. Γs (0) is the value of the surface tension of the liquid excluding all the surfactants in the composition of the undercoat liquid. γs (saturation) is obtained when one surfactant among the surfactants contained in the undercoat liquid is added to the “liquid excluding all surfactants” and the concentration of the surfactant is increased. The surface tension value of the liquid with the surface tension saturated. The γs (saturation) ^maximum is the maximum value of γs (saturation) obtained for all surfactants satisfying the condition (B) among the surfactants contained in the undercoat liquid.

  The γs (0) is obtained by measuring the surface tension value of the liquid excluding all surfactants in the composition of the undercoat liquid. The γs (saturation) is obtained by adding one surfactant among the surfactants contained in the undercoat liquid to the “liquid excluding all the surfactants”, and adjusting the concentration of the surfactant. It can be obtained by measuring the surface tension of the liquid when the change amount of the surface tension with respect to the change of the surfactant concentration becomes 0.01 mN / m or less when it is increased by 0.01% by mass.

Hereinafter, the γs (0), γs (saturation), and γs (saturation) ^maximum will be specifically described.
For example, the components constituting the undercoat liquid (Example 1) are a high boiling point solvent (diethyl phthalate, manufactured by Wako Pure Chemical Industries, Ltd.), a polymerizable material (dipropylene glycol diacrylate, manufactured by Akcros), a polymerization initiator. (TPO, the following initiator-1), fluorosurfactant (Megafac F475, manufactured by Dainippon Ink & Chemicals, Inc.), hydrocarbon surfactant (di-2-ethylhexyl sodium sulfosuccinate) Γs (0), γs (saturated) ¹ (when a fluorosurfactant is added), γs (saturated) ² (when a hydrocarbon surfactant is added), γs (saturated), and γs The (saturation) ^maximum is as follows.

That is, γs (0) is the surface tension value of the liquid of the undercoat liquid excluding all the surfactants, and is 36.7 mN / m. Further, when the saturation value of the surface tension of the liquid when the concentration is increased by adding the fluorosurfactant to the liquid is γs (saturation) ¹ , the value is 20.2 mN / m. . Furthermore, when the hydrocarbon surfactant is added to the liquid and the concentration of the surface tension of the liquid is increased to γs (saturated) ² when the concentration is increased, the value is 30.5 mN / m.

Since the undercoat liquid (Example 1) contains two types of surfactants that satisfy the condition (B), γs (saturated) is carbonized when a fluorosurfactant is added (γs (saturated) ¹ ). Two values (γs (saturated) ² ) can be taken when the hydrogen-based surfactant is added. Here, since γs (saturation) ^maximum is the maximum value of γs (saturation) ¹ and γs (saturation) ² , it is a value of γs (saturation) ² .
From the above, they are summarized as follows.
γs (0) = 36.7 mN / m
γs (saturated) ¹ = 20.2 mN / m (when a fluorosurfactant is added)
γs (saturated) ² = 30.5 mN / m (when a hydrocarbon surfactant is added)
γs (saturation) ^maximum = 30.5 mN / m

From the above results, the surface tension γs of the undercoat liquid in the above specific example is
γs <(γs (0) + γs (saturation) ^maximum ) /2=33.6 mN / m
It is preferable to satisfy the relationship.
As for the condition (C), from the viewpoint of more effectively preventing expansion of ink droplets from landing to exposure, as the surface tension of the undercoat liquid,
γs <γs (0) −3 × {γs (0) −γs (saturation) ^maximum } / 4
It is more preferable to satisfy the relationship
γs ≦ γs (saturation) ^maximum
It is particularly preferable to satisfy this relationship.

  The composition of the ink and the undercoat liquid may be selected so as to obtain a desired surface tension, but these liquids preferably contain a surfactant. As described above, in order to form ink dots of a desired size on the recording medium, the undercoat liquid preferably contains at least one surfactant. The surfactant will be described below.

(Surfactant)
As the surfactant in the present invention, hexane, cyclohexane, p-xylene, toluene, ethyl acetate, methyl ethyl ketone, butyl carbitol, cyclohexanone, triethylene glycol monobutyl ether, 1,2-hexanediol, propylene glycol monomethyl ether, isopropanol, Substances having strong surface activity against at least one solvent among methanol, water, isobornyl acrylate, 1,6-hexane diacrylate and polyethylene glycol diacrylate, preferably hexane, toluene, propylene glycol monomethyl ether, iso Strong surface activity against at least one solvent among bonyl acrylate, 1,6-hexane diacrylate and polyethylene glycol diacrylate More preferably, a substance having strong surface activity against at least one solvent among propylene glycol monomethyl ether, isobornyl acrylate, 1,6-hexane diacrylate, and polyethylene glycol diacrylate, particularly preferably , Isobonyl acrylate, 1,6-hexane diacrylate, and polyethylene glycol diacrylate are preferably used.

Whether or not a certain compound has a strong surface activity with respect to the solvents listed above can be determined by the following procedure.
(procedure)
One solvent is selected from the solvents listed above, and the surface tension γ _solvent (0) of the _solvent is measured. The compound is added to the same solution as the solvent for obtaining the γ _solvent (0), the concentration of the compound is increased by 0.01% by mass, and the change in the surface tension with respect to the change in the compound concentration is 0.01 mN / m. Measure the surface tension γ _solvent (saturation) of the solution when: The relationship between the γ _solvent (0) and the γ _solvent (saturated) is
γ _solvent (0) −γ _solvent (saturated)> 1 (mN / m)
If so, it can be determined that the compound is a substance having a strong surface activity with respect to the solvent.

  Specific examples of the surfactant contained in the undercoat liquid include anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalenesulfonates, fatty acid salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, Nonionic surfactants such as acetylene glycols and polyoxyethylene / polyoxypropylene block copolymers, cationic surfactants such as alkylamine salts and quaternary ammonium salts, and fluorosurfactants. In addition, examples of the surfactant include those described in JP-A Nos. 62-173463 and 62-183457.

(Curing sensitivity of ink and undercoat liquid)
In the present invention, the curing sensitivity of the ink is preferably equal to or higher than the curing sensitivity of the undercoat liquid. The curing sensitivity of the ink is more preferably set to be equal to or higher than the curing sensitivity of the undercoat liquid and 4 times or less of the curing sensitivity of the undercoat liquid, and is set to be equal to or higher than the curing sensitivity of the undercoat liquid and not more than twice the curing sensitivity of the undercoat liquid. Is more preferable.
Here, the curing sensitivity is the amount of energy required for complete curing when the ink and / or undercoat liquid is cured using a mercury lamp (ultrahigh pressure, high pressure, medium pressure, etc., preferably an ultrahigh pressure mercury lamp). The smaller the amount of energy, the higher the sensitivity. Therefore, a curing sensitivity of 2 means that the amount of energy required for complete curing is ½.
Further, the phrase “curing sensitivity is equivalent” means that the difference in curing sensitivity between the two compared is 2 times or less, more preferably 1.5 times or less.

(Recording medium)
In the ink jet recording apparatus of this embodiment, any of a permeable recording medium, a non-permeable recording medium, and a slowly permeable recording medium can be used as the recording medium. In particular, when a non-permeable or slowly permeable recording medium is used as the recording medium, the effects of the present invention can be obtained more remarkably. Here, the permeable recording medium is a recording medium in which, for example, when a 10 pL (picoliter) droplet is dropped on the recording medium, the time until the entire liquid amount permeates is 100 ms or less. Say. Further, the non-permeable recording medium refers to a recording medium in which liquid droplets do not substantially permeate. “Substantially does not penetrate” means, for example, that the penetration rate of a droplet after 1 minute is 5% or less. Further, the slow-penetrating recording medium refers to a recording medium in which when a 10 pL droplet is dropped on the recording medium, the time until the entire liquid amount permeates is 100 ms or more.

Examples of the permeable recording medium include plain paper, porous paper, and other recording media that can absorb liquid.
Examples of the non-permeable or slowly permeable recording medium include art paper, synthetic resin, rubber, resin-coated paper, glass, metal, earthenware, and wood. In the present invention, a recording medium obtained by combining a plurality of these materials can be used for the purpose of adding functions.

  As the recording medium of the synthetic resin, any synthetic resin can be used. For example, polyesters such as polyethylene terephthalate and polybutadiene terephthalate, polyolefins such as polyvinyl chloride, polystyrene, polyethylene, polyurethane, and polypropylene, acrylic resins, polycarbonates, Examples include acrylonitrile-butadiene-styrene copolymer, diacetate, triacetate, polyimide, cellophane, celluloid and the like. The thickness and shape of the recording medium when using a synthetic resin are not particularly limited, and may be any of a film shape, a card shape, and a block shape, and may be transparent or opaque. Good.

  As the recording medium of this synthetic resin, it is also preferable to use various non-absorbing plastics in the form of films used for so-called soft packaging and films thereof. Examples of the plastic film include a PET film, an OPS film, an OPP film, a PNy film, a PVC film, a PE film, a TAC film, and a PP film. Other plastics that can be used include polycarbonate, acrylic resin, ABS, polyacetal, PVA, and rubbers.

  Examples of the recording medium for resin-coated paper include a transparent polyester film, an opaque polyester film, an opaque polyolefin resin film, and a paper support in which both sides of paper are laminated with a polyolefin resin. In particular, it is preferable to use a paper support in which both sides of paper are laminated with a polyolefin resin.

  The metal recording medium is not particularly limited, and for example, aluminum, iron, gold, silver, copper, nickel, titanium, chromium, molybdenum, silicon, lead, zinc, etc. and stainless steel, and composite materials thereof are suitable. Can be used.

  Furthermore, as a recording medium, a read-only optical disk such as a CD-ROM or DVD-ROM, a write-once optical disk such as a CD-R or DVD-R, a rewritable optical disk, or the like can be used. In this case, it is preferable to record an image on the so-called label surface side.

(Ink and undercoat liquid)
Hereinafter, the ink and the undercoat liquid that can be suitably used in the present invention will be described in detail.

The ink has a composition that forms at least an image, includes at least one polymerizable or crosslinkable material, and uses a polymerization initiator, a lipophilic solvent, a colorant, and other components as necessary. Composed.
The undercoat liquid preferably contains at least one polymerizable or crosslinkable material, and is composed of a polymerization initiator, a lipophilic solvent, a colorant and other components as necessary. Further, the undercoat liquid is preferably configured to have a composition different from that of the ink.

The polymerization initiator is preferably capable of initiating a polymerization reaction or a crosslinking reaction by active energy rays. As a result, the undercoat liquid applied to the recording medium can be cured by irradiation with active energy rays.
Moreover, it is preferable that undercoat liquid contains a radically polymerizable composition. In the present invention, the radical polymerizable composition is a composition containing at least one radical polymerizable material and at least one radical polymerization initiator. When the undercoat liquid contains a radically polymerizable composition, the curing reaction of the undercoat liquid can be performed with high sensitivity in a short time.
The ink preferably contains a colorant. In addition, the undercoat liquid used in combination with this ink is either a composition containing no colorant or having a colorant content of less than 1% by mass, or a composition in which the undercoat liquid contains a white pigment as a colorant. Preferably there is.
Hereinafter, each component constituting the ink and / or undercoat liquid will be described in detail.

(Polymerizable or crosslinkable material)
The polymerizable or crosslinkable material has a function of causing a polymerization or crosslinking reaction by an initiating species such as a radical generated from a polymerization initiator described later, and curing a composition containing these.

As the polymerizable or crosslinkable material, a polymerizable or crosslinkable material that causes a known polymerization or crosslinking reaction such as radical polymerization reaction or dimerization reaction can be applied. For example, an addition polymerizable compound having at least one ethylenically unsaturated double bond, a polymer compound having a maleimide group in the side chain, a cinnamyl group having a photodimerizable unsaturated double bond adjacent to the aromatic nucleus, Examples thereof include a polymer compound having a cinnamylidene group or a chalcone group in the side chain. Among these, an addition polymerizable compound having at least one ethylenically unsaturated double bond is more preferable, and from a compound (monofunctional or polyfunctional compound) having at least one terminal ethylenically unsaturated bond, more preferably two or more. It is particularly preferred that it is selected. Specifically, it can be appropriately selected from those widely known in the industrial field according to the present invention. For example, monomers, prepolymers (that is, dimers, trimers, and oligomers) and mixtures thereof, and those Those having a chemical form such as a copolymer of
A polymeric or crosslinkable material may be used individually by 1 type, and may be used in combination of 2 or more type.

As the polymerizable or crosslinkable material in the present invention, it is particularly preferable to use various known radically polymerizable monomers that cause a polymerization reaction with an initiating species generated from a radical initiator.
Examples of the radical polymerizable monomer include (meth) acrylates, (meth) acrylamides, aromatic vinyls, vinyl ethers, and compounds having an internal double bond (such as maleic acid). Here, “(meth) acrylate” refers to both and / or “acrylate” and “methacrylate”, and “(meth) acryl” refers to both and / or “acryl” and “methacryl”.

Examples of (meth) acrylates include the following.
Specific examples of monofunctional (meth) acrylates include hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, tert-octyl (meth) acrylate, isoamyl (meth) acrylate, decyl (meth) acrylate, isodecyl ( (Meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, 4-n-butylcyclohexyl (meth) acrylate, bornyl (meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) Acrylate, 2-ethylhexyl diglycol (meth) acrylate, butoxyethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 4-bromobutyl (meth) acrylate, shear Ethyl (meth) acrylate, benzyl (meth) acrylate, butoxymethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, alkoxymethyl (meth) acrylate, alkoxyethyl (meth) acrylate, 2- (2-methoxyethoxy) ethyl (Meth) acrylate, 2- (2-butoxyethoxy) ethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, 1H, 1H, 2H, 2H-perfluorodecyl (meth) acrylate, 4 -Butylphenyl (meth) acrylate, phenyl (meth) acrylate, 2,4,5-tetramethylphenyl (meth) acrylate, 4-chlorophenyl (meth) acrylate, phenoxymethyl (meth) acrylate, phenoxyethyl (meth) Acrylate, glycidyl (meth) acrylate, glycidyloxybutyl (meth) acrylate, glycidyloxyethyl (meth) acrylate, glycidyloxypropyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, hydroxyalkyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate,

2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, Diethylaminopropyl (meth) acrylate, trimethoxysilylpropyl (meth) acrylate, trimethylsilylpropyl (meth) acrylate, polyethylene oxide monomethyl ether (meth) acrylate, oligoethylene oxide monomethyl ether (meth) acrylate, polyethylene oxide (meth) acrylate, oligoethylene oxide (Meth) acrylate, oligoethylene oxide monoalkyl ether (meth) acrylate, Reethylene oxide monoalkyl ether (meth) acrylate, dipropylene glycol (meth) acrylate, polypropylene oxide monoalkyl ether (meth) acrylate, oligopropylene oxide monoalkyl ether (meth) acrylate, 2-methacryloyloxytyl succinic acid, 2- Methacryloyloxyhexahydrophthalic acid, 2-methacryloyloxyethyl-2-hydroxypropyl phthalate, butoxydiethylene glycol (meth) acrylate, trifluoroethyl (meth) acrylate, perfluorooctylethyl (meth) acrylate, 2-hydroxy-3 -Phenoxypropyl (meth) acrylate, EO modified phenol (meth) acrylate, EO modified cresol (meth) acrylate, EO modified noni Phenol (meth) acrylate, PO-modified nonylphenol (meth) acrylate, EO-modified 2-ethylhexyl (meth) acrylate and the like.

  Specific examples of the bifunctional (meth) acrylate include 1,6-hexanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 2,4- Dimethyl-1,5-pentanediol di (meth) acrylate, butylethylpropanediol (meth) acrylate, ethoxylated cyclohexanemethanol di (meth) acrylate, polyethylene glycol di (meth) acrylate, oligoethylene glycol di (meth) acrylate , Ethylene glycol di (meth) acrylate, 2-ethyl-2-butyl-butanediol di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, EO-modified bisphenol A di (meth) acrylate Bisphenol F polyethoxydi (meth) acrylate, polypropylene glycol di (meth) acrylate, oligopropylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 2-ethyl-2-butylpropanediol di (Meth) acrylate, 1,9-nonane di (meth) acrylate, propoxylated ethoxylated bisphenol A di (meth) acrylate, tricyclodecane di (meth) acrylate and the like.

  Specific examples of trifunctional (meth) acrylates include trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane alkylene oxide modified tri (meth) acrylate, pentaerythritol tri (meth) Acrylate, dipentaerythritol tri (meth) acrylate, trimethylolpropane tris ((meth) acryloyloxypropyl) ether, isocyanuric acid alkylene oxide modified tri (meth) acrylate, dipentaerythritol tri (meth) acrylate propionate, tris (( (Meth) acryloyloxyethyl) isocyanurate, hydroxypivalaldehyde-modified dimethylolpropane tri (meth) acrylate, sorbitol tri (meta) Acrylate, propoxylated trimethylolpropane tri (meth) acrylate, and the like ethoxylated glycerol triacrylate.

  Specific examples of tetrafunctional (meth) acrylates include pentaerythritol tetra (meth) acrylate, sorbitol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate propionate, ethoxylation Examples include pentaerythritol tetra (meth) acrylate.

  Specific examples of the pentafunctional (meth) acrylate include sorbitol penta (meth) acrylate and dipentaerythritol penta (meth) acrylate.

  Specific examples of hexafunctional (meth) acrylates include dipentaerythritol hexa (meth) acrylate, sorbitol hexa (meth) acrylate, phosphazene alkylene oxide modified hexa (meth) acrylate, captolactone modified dipentaerythritol hexa (meth) An acrylate etc. are mentioned.

  Examples of (meth) acrylamides include (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, and Nn-butyl (meth) acrylamide. N-t-butyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-methylol (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N- Examples include diethyl (meth) acrylamide, (meth) acryloylmorpholine, and the like.

  Specific examples of aromatic vinyls include styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, isopropyl styrene, chloromethyl styrene, methoxy styrene, acetoxy styrene, chloro styrene, dichloro styrene, bromo styrene, vinyl benzoic acid. Methyl ester, 3-methylstyrene, 4-methylstyrene, 3-ethylstyrene, 4-ethylstyrene, 3-propylstyrene, 4-propylstyrene, 3-butylstyrene, 4-butylstyrene, 3-hexylstyrene, 4- Hexyl styrene, 3-octyl styrene, 4-octyl styrene, 3- (2-ethylhexyl) styrene, 4- (2-ethylhexyl) styrene, allyl styrene, isopropenyl styrene, butenyl styrene, octenyl Styrene, 4-t-butoxycarbonyl styrene, 4-methoxystyrene, and a 4-t-butoxystyrene.

  Specific examples of vinyl ethers include, as examples of monofunctional vinyl ethers, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, t-butyl vinyl ether, 2-ethylhexyl vinyl ether, n-nonyl vinyl ether, lauryl vinyl ether, cyclohexyl vinyl ether, Cyclohexylmethyl vinyl ether, 4-methylcyclohexyl methyl vinyl ether, benzyl vinyl ether, dicyclopentenyl vinyl ether, 2-dicyclopentenoxyethyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, butoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, ethoxyethoxyethyl vinyl ether , Methoxypolye Lenglycol vinyl ether, tetrahydrofurfuryl vinyl ether, 2-hydroxyethyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 4-hydroxymethylcyclohexyl methyl vinyl ether, diethylene glycol monovinyl ether, polyethylene glycol vinyl ether, chloroethyl vinyl ether, chlorobutyl vinyl ether Chloroethoxyethyl vinyl ether, phenylethyl vinyl ether, phenoxypolyethylene glycol vinyl ether, and the like.

Examples of polyfunctional vinyl ethers include ethylene glycol divinyl ether, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, bisphenol A alkylene oxide divinyl ether, bisphenol F alkylene oxide. Divinyl ethers such as divinyl ether; trimethylolethane trivinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol hexa Nyl ether, ethylene oxide-added trimethylolpropane trivinyl ether, propylene oxide-added trimethylolpropane trivinyl ether, ethylene oxide-added ditrimethylolpropane tetravinyl ether, propylene oxide-added ditrimethylolpropane tetravinyl ether, ethylene oxide-added pentaerythritol tetravinyl ether, propylene oxide-added pentane And polyfunctional vinyl ethers such as erythritol tetravinyl ether, ethylene oxide-added dipentaerythritol hexavinyl ether, and propylene oxide-added dipentaerythritol hexavinyl ether.
The vinyl ether compound is preferably a di- or trivinyl ether compound, and more preferably a divinyl ether compound, particularly from the viewpoints of curability, adhesion to a recording medium, and surface hardness of the formed image. .

  In addition to the above, the radical polymerizable monomer further includes vinyl esters [vinyl acetate, vinyl propionate, vinyl versatate, etc.], allyl esters [allyl acetate, etc.], halogen-containing monomers [vinylidene chloride, Vinyl chloride etc.], vinyl cyanide [(meth) acrylonitrile etc.], olefins [ethylene, propylene etc.] and the like.

  Among the above, as the radical polymerizable monomer, it is preferable to use (meth) acrylates and (meth) acrylamides from the viewpoint of curing speed, and particularly from the viewpoint of curing speed, tetrafunctional or higher functional (meth) acrylate is preferably used. It is preferable to use it. Furthermore, from the viewpoint of the viscosity of the ink composition, it is preferable to use a polyfunctional (meth) acrylate in combination with a monofunctional or bifunctional (meth) acrylate or (meth) acrylamide.

The content of the polymerizable or crosslinkable material in the ink and undercoat liquid is preferably in the range of 50 to 99.6% by mass with respect to the total solid content (mass) of each droplet, and is preferably 70 to 99. It is more preferable to set it as the range of 0.0 mass%, and it is further more preferable to set it as the range of 80-99.0 mass%.
Moreover, as content in a droplet, it is preferable to set it as the range of 20-98 mass% with respect to the total mass of each droplet, The range of 40-95 mass% is more preferable, 50-90 mass% It is particularly preferable to set the range.

(Polymerization initiator)
Moreover, it is preferable that at least the undercoat liquid, or the ink and the undercoat liquid contain at least one polymerization initiator. This polymerization initiator generates radicals and other starting species by applying actinic light, heat, or both, and initiates, accelerates and cures the polymerization or crosslinking reaction of the polymerizable or crosslinkable material described above. A compound.

In the polymerizable embodiment, it preferably contains a polymerization initiator that causes radical polymerization, and more preferably a photopolymerization initiator.
A photopolymerization initiator is a compound that generates a chemical change by the action of light and interaction with the electronically excited state of a sensitizing dye to generate at least one of a radical, an acid, and a base. From the viewpoint that polymerization can be initiated by such simple means, a photo radical generator is preferred.

  As the photopolymerization initiator in the present invention, irradiated actinic rays, for example, ultraviolet rays of 400 to 200 nm, deep ultraviolet rays, g rays, h rays, i rays, KrF excimer laser rays, ArF excimer laser rays, electron rays, X Those having sensitivity to a beam, molecular beam, ion beam, or the like can be appropriately selected and used.

  Specific photopolymerization initiators known among those skilled in the art can be used without limitation. For example, Bruce M. et al. Monroe et al., Chemical Review, 93, 435 (1993). R. S. By Davidson, Journal of Photochemistry and biologic A: Chemistry, 73.81 (1993). J. P. Faussier “Photoinitiated Polymerization—Theory and Applications”: Rapra Review vol. 9, Report, Rapra Technology (1998). M. Tsunooka et al. , Prog. Polym. Sci. , 21, 1 (1996). Many are described. Further, F.I. D. Saeva, Topics in Current Chemistry, 156, 59 (1990). G. G. Maslak, Topics in Current Chemistry, 168, 1 (1993). H., et al. B. Shuster et al, JACS, 112, 6329 (1990). , I. D. F. Eaton et al, JACS, 102, 3298 (1980). A compound group that undergoes oxidative or reductive bond cleavage through interaction with the electronically excited state of the sensitizing dye described in the above can also be used.

  Preferred photopolymerization initiators include (a) aromatic ketones, (b) aromatic onium salt compounds, (c) organic peroxides, (d) hexaarylbiimidazole compounds, (e) ketoxime ester compounds, (F) borate compounds, (g) azinium compounds, (h) metallocene compounds, (i) active ester compounds, (j) compounds having a carbon halogen bond, and the like.

  Preferable examples of the (a) aromatic ketones include “RADIATION CURING IN POLYMER SCIENCE AND TECHNOLOGY” P. FOUASSIER J.M. F. Examples include compounds having a benzophenone skeleton or a thioxanthone skeleton described in RABEK (1993), p77-117. More preferable examples of (a) aromatic ketones include α-thiobenzophenone compounds described in JP-B-47-6416, benzoin ether compounds described in JP-B-47-3981, and JP-B-47-22326. Α-substituted benzoin compounds, benzoin derivatives described in JP-B-47-23664, aroylphosphonic acid esters described in JP-A-57-30704, dialkoxybenzophenones described in JP-B-60-26483, Benzoin ethers described in JP-A-60-26403, JP-A-62-81345, JP-B-1-34242, US Pat. No. 4,318,791, and α-aminobenzophenones described in European Patent 0284561A1, P-di (dimethyla) described in JP-A-2-211452 Nobenzoyl) benzene, thio-substituted aromatic ketone described in JP-A-61-194062, acylphosphine sulfide described in JP-B-2-9597, acylphosphine described in JP-B-2-9596, JP-B-63- Examples thereof include thioxanthones described in Japanese Patent No. 61950, and coumarins described in Japanese Patent Publication No. 59-42864.

  Here, as the (b) aromatic onium salt compound, elements of Group V, VI and VII of the periodic table, specifically N, P, As, Sb, Bi, O, S, Se, Te, Or an aromatic onium salt of I. For example, iodonium salts described in European Patent No. 104143, US Pat. No. 4,837,124, Japanese Patent Laid-Open No. 2-150848, Japanese Patent Laid-Open No. 2-96514, European Patent Nos. 370693, 233567, and 297443 are disclosed. , 294442, 279210, and 422570, U.S. Pat. Nos. 3,902,144, 4,933,377, 4,760013, 4,734,344, and 2,833,827, sulfonium salts and diazonium salts (Such as benzenediazonium which may have a substituent), diazonium salt resins (formaldehyde resin of diazodiphenylamine, etc.), N-alkoxypyridinium salts, etc. (for example, US Pat. No. 4,743,528, JP 63-138345 JP-A-63-142345, JP-A-63-142346, and JP-B-46-42363, specifically 1-methoxy-4-phenylpyridinium tetrafluoroborate, etc. In addition, compounds described in JP-B Nos. 52-147277, 52-14278, and 52-14279 can be preferably used. Generates radicals and acids as active species.

  Further, (c) “organic peroxide” includes almost all organic compounds having one or more oxygen-oxygen bonds in the molecule. For example, 3,3 ′, 4,4′-tetrakis ( t-butylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetrakis (t-amylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetrakis (t-hexylperoxycarbonyl) benzophenone 3,3 ′, 4,4′-tetrakis (t-octylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetrakis (cumylperoxycarbonyl) benzophenone, 3,3′4,4′- Peroxides such as tetrakis (p-isopropylcumylperoxycarbonyl) benzophenone and di-t-butyldiperoxyisophthalate It is preferable to use an ether-based.

  Examples of (d) hexaarylbiimidazole include lophine dimers described in JP-B Nos. 45-37377 and 44-86516, such as 2,2′-bis (o-chlorophenyl) -4,4 ′. , 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-bromophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o, p- Dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetrakis (m-methoxyphenyl) biimidazole, 2,2′-bis (o, o′-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-nitrophenyl) -4,4 ′, 5 '-Tetraphenylbiimidazole, 2,2'-bis (o-methylphenyl) -4,4', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-trifluorophenyl) -4 , 4 ′, 5,5′-tetraphenylbiimidazole and the like.

  Examples of the (e) ketoxime ester include 3-benzoyloxyiminobutane-2-one, 3-acetoxyiminobutan-2-one, 3-propionyloxyiminobutan-2-one, and 2-acetoxyimino. Pentan-3-one, 2-acetoxyimino-1-phenylpropan-1-one, 2-benzoyloxyimino-1-phenylpropan-1-one, 3-p-toluenesulfonyloxyiminobutan-2-one, And 2-ethoxycarbonyloxyimino-1-phenylpropan-1-one.

Examples of the (f) borate compound include compounds described in US Pat. Nos. 3,567,453, 4,343,891, European Patents 109,772, and 109,773. .
Examples of (g) azinium salt compounds include JP-A-63-138345, JP-A-63-142345, JP-A-63-142346, JP-A-63-143537, and JP-B-46- The compound group which has NO bond as described in each gazette of 42363 is raised.

  Examples of (h) metallocene compounds include JP-A-59-152396, JP-A-61-151197, JP-A-63-41484, JP-A-2-249, and JP-A-2-4705. Examples thereof include titanocene compounds described in the publication, and iron-arene complexes described in JP-A-1-304453 and JP-A-1-152109.

  Specific examples of the titanocene compound include di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, and di-cyclopentadienyl-Ti-bis-2,3,4. , 5,6-pentafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti-bis -2,4,6-trifluorophen-1-yl, di-cyclopentadienyl-Ti-2,6-difluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4- Difluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis 2,3,5,6-tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4-difluorophen-1-yl, bis (cyclopentadienyl) -bis (2 , 6-Difluoro-3- (pyridin-1-yl) phenyl) titanium, bis (cyclopentadienyl) bis [2,6-difluoro-3- (methylsulfonamido) phenyl] titanium, bis (cyclopentadienyl) ) Bis [2,6-difluoro-3- (N-butylbialoyl-amino) phenyl] titanium and the like.

  Examples of (i) active ester compounds include European Patent Nos. 0290750, 046083, 156153, 271851, and 0388343, U.S. Pat. Nos. 3,901,710, and 4,181,531. Nitrobenzyl ester compounds described in JP-A-60-198538 and JP-A-53-133022, European Patent Nos. 099672, 84515, 199672, 0441115, and 0101122, respectively. Specifications, U.S. Pat. Nos. 4,618,564, 4,371,605, and 4,431,774, JP-A 64-18143, JP-A-2-245756, and JP-A-4-365048, respectively. JP-B 62-6223, JP-B 63-14 No. 40, and compounds, and the like described in the JP-A-59-174831.

  Moreover, (j) As a preferable example of the compound which has a carbon halogen bond, Wakabayashi et al., Bull. Chem. Soc. Examples include compounds described in Japan, 42, 2924 (1969), compounds described in British Patent 1388492, compounds described in JP-A-53-133428, compounds described in German Patent 3333724, and the like.

  F.F. C. J. Schaefer et al. Org. Chem. 29, 1527 (1964), compounds described in JP-A-62-258241, compounds described in JP-A-5-281728, and the like. Further, a compound as described in German Patent No. 2641100, a compound described in German Patent No. 3333450, a compound group described in German Patent No. 3021590, or a compound group described in German Patent No. 3021599 , Etc.

  As a photoinitiator in this invention, although the compound illustrated below can be mentioned, for example, It is not limited to these.

  In addition, as a polymerization initiator, what is excellent in a sensitivity is preferable, However, From a viewpoint of storage stability, it is preferable to use the polymerization initiator which does not raise | generate thermal decomposition at the temperature to 80 degreeC.

  A polymerization initiator can be used 1 type or in combination of 2 or more types. Moreover, a well-known sensitizer can also be used together for the purpose of a sensitivity improvement in the range which does not impair the effect of this invention.

  As content in the undercoat liquid of a polymerization initiator, it shall be in the range of 0.5-20 mass% with respect to the polymeric material in undercoat liquid from a viewpoint of temporal stability, sclerosis | hardenability, and a cure rate. Is preferable, it is more preferable to set it as 1-15 mass%, and it is especially preferable to set it as 3-10 mass%. By setting the content within the above range, it is possible to suppress the occurrence of precipitation or separation over time, or the deterioration of performance such as the strength and rubbing resistance of the ink after curing.

  The polymerization initiator may be contained in the ink as well as in the undercoat liquid. In this case, the polymerization initiator may be appropriately selected and contained within a range in which the storage stability of the ink can be maintained at a desired level. In this case, the content in the ink droplet is preferably 0.5 to 20% by mass and more preferably 1 to 15% by mass with respect to the polymerizable or crosslinkable compound in the ink. .

(Sensitizing dye)
In addition, a sensitizing dye is preferably added to the ink and / or undercoat liquid for the purpose of improving the sensitivity of the photopolymerization initiator. Examples of preferred sensitizing dyes include those belonging to the following compounds and having an absorption wavelength in the 350 nm to 450 nm region.

  Specifically, polynuclear aromatics (eg, pyrene, perylene, triphenylene), xanthenes (eg, fluorescein, eosin, erythrosine, rhodamine B, rose bengal), cyanines (eg, thiacarbocyanine, oxacarbocyanine) ), Merocyanines (eg merocyanine, carbomerocyanine), thiazines (eg thionine, methylene blue, toluidine blue), acridines (eg acridine orange, chloroflavin, acriflavine), anthraquinones (eg anthraquinone), squalium (For example, squalium) and coumarins (for example, 7-diethylamino-4-methylcoumarin).

  Examples of more preferable sensitizing dyes include compounds represented by the following general formulas (IX) to (XIII).

In the formula (IX), A ¹ represents a sulfur atom or —NR ⁵⁰ —, R ⁵⁰ represents an alkyl group or an aryl group, and L ² represents a basic nucleus of the dye in combination with the adjacent A ¹ and the adjacent carbon atom. R ⁵¹ and R ⁵² each independently represents a hydrogen atom or a monovalent nonmetallic atomic group, and R ⁵¹ and R ⁵² are bonded to each other to form an acidic nucleus of the dye. May be. W represents an oxygen atom or a sulfur atom.
In formula (X), Ar ¹ and Ar ² each independently represent an aryl group and are linked via a bond with —L ³ —. Here, L ³ represents —O— or —S—. W is synonymous with that shown in the general formula (IX).
In the formula (XI), A ² represents a sulfur atom or —NR ⁵⁹ —, L ⁴ represents a nonmetallic atomic group that forms a basic nucleus of the dye together with the adjacent A ² and carbon atom, and R ⁵³ , R ⁵⁴ , R ⁵⁵ , R ⁵⁶ , R ⁵⁷ and R ⁵⁸ each independently represents a monovalent non-metallic atomic group, and R ⁵⁹ represents an alkyl group or an aryl group.

In formula (XII), A ³ and A ⁴ each independently represent —S— or —NR ⁶² — or —NR ⁶³ —, and R ⁶² and R ⁶³ each independently represent a substituted or unsubstituted alkyl group, substituted or Represents an unsubstituted aryl group, and L ⁵ and L ⁶ each independently represent a nonmetallic atomic group that forms a basic nucleus of a dye in cooperation with adjacent A ³ , A ^4, and adjacent carbon atoms, and R ⁶⁰ , R ⁶¹ each independently represents a hydrogen atom or a monovalent nonmetallic atomic group, or may be bonded to each other to form an aliphatic or aromatic ring.
In formula (XIII), R ⁶⁶ represents an aromatic ring or a hetero ring which may have a substituent, and A ⁵ represents an oxygen atom, a sulfur atom or —NR ⁶⁷ —. R ⁶⁴ , R ⁶⁵ and R ⁶⁷ each independently represent a hydrogen atom or a monovalent non-metallic atomic group, R ⁶⁷ and R ⁶⁴ , and R ⁶⁵ and R ⁶⁷ each represent an aliphatic or aromatic ring. Can be combined to form.

  Specific examples of the compounds represented by the general formulas (IX) to (XIII) include the exemplified compounds (A-1) to (A-20) shown below.

(Co-sensitizer)
Furthermore, it is preferable to add a known compound as a co-sensitizer to the ink and / or undercoat liquid that has a function of further improving sensitivity or suppressing polymerization inhibition by oxygen.
Examples of co-sensitizers include amines such as M.I. R. Sander et al., “Journal of Polymer Society”, Vol. 10, 3173 (1972), Japanese Patent Publication No. 44-20189, Japanese Patent Publication No. 51-82102, Japanese Patent Publication No. 52-134692, Japanese Patent Publication No. 59-138205. No. 60-84305, JP-A 62-18537, JP-A 64-33104, Research Disclosure 33825, and the like. Specific examples include triethanolamine. P-dimethylaminobenzoic acid ethyl ester, p-formyldimethylaniline, p-methylthiodimethylaniline and the like.

Other examples include thiols and sulfides, for example, thiol compounds described in JP-A-53-702, JP-B-55-500806, JP-A-5-142772, and JP-A-56-75643. Specific examples include 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, 2-mercapto-4- (3H) -quinazoline, β-mercaptonaphthalene, and the like. It is done.
Other examples include amino acid compounds (eg, N-phenylglycine), organometallic compounds described in Japanese Patent Publication No. 48-42965 (eg, tributyltin acetate), and hydrogen described in Japanese Patent Publication No. 55-34414. Donors, sulfur compounds described in JP-A-6-308727 (eg, trithiane), phosphorus compounds described in JP-A-6-250387 (diethylphosphite, etc.), Si-- described in JP-A-8-65779 H, Ge-H compound, etc. are mentioned.

(Coloring agent)
At least the ink or the ink and the undercoat liquid contain at least one colorant. In addition to the ink, the colorant may be contained in an undercoat liquid or other liquid.

  The colorant is not particularly limited, and can be appropriately selected from known water-soluble dyes, oil-soluble dyes, pigments, and the like. In particular, when the ink and the undercoat liquid are composed of a water-insoluble organic solvent system that can suitably obtain the effects of the present invention, the colorant is an oil-soluble material that is easily dispersed and dissolved in a water-insoluble medium. It is preferable to use dyes and pigments.

  The content of the colorant in the ink is preferably 1 to 30% by mass, more preferably 1.5 to 25% by mass, and particularly preferably 2 to 15% by mass. When the undercoat liquid contains a white pigment as the colorant, the content of the colorant in the undercoat liquid is preferably 2 to 45% by mass, and more preferably 4 to 35% by mass.

Hereinafter, the pigment suitable for the present invention will be mainly described.
<Pigment>
An embodiment using a pigment as the colorant is preferred.
As the pigment, either an organic pigment or an inorganic pigment can be used, and as the black pigment, a carbon black pigment or the like is preferable. In general, pigments of three primary colors of black and cyan, magenta, and yellow are used, but other hues such as pigments having hues such as red, green, blue, brown, white, gold, silver, etc. Metal luster pigments, colorless or light extender pigments, and the like can also be used depending on the purpose.

  The organic pigment is not limited in hue, and includes, for example, perylene, perinone, quinacridone, quinacridonequinone, anthraquinone, anthanthrone, benzimidazolone, disazo condensation, disazo, azo, indanthrone, phthalocyanine, triaryl carbo Examples thereof include nium, dioxazine, aminoanthraquinone, diketopyrrolopyrrole, thioindigo, isoindoline, isoindolinone, pyranthrone, isoviolanthrone pigment, and mixtures thereof.

  More specifically, for example, C.I. I. Pigment red 190 (C.I. No. 71140), C.I. I. Pigment red 224 (C.I. No. 71127), C.I. I. Perylene pigments such as CI Pigment Violet 29 (C.I. No. 71129); I. Pigment orange 43 (C.I. No. 71105) or C.I. I. Perinone pigments such as CI Pigment Red 194 (C.I. No. 71100); I. Pigment violet 19 (C.I. No. 73900), C.I. I. Pigment violet 42, C.I. I. Pigment red 122 (C.I. No. 73915), C.I. I. Pigment red 192, C.I. I. Pigment red 202 (C.I. No. 73907), C.I. I. Pigment red 207 (C.I. No. 73900, 73906), or C.I. I. Pigment Red 209 (C.I. No. 73905), a quinacridone pigment, C.I. I. Pigment red 206 (C.I. No. 73900/73920), C.I. I. Pigment orange 48 (C.I. No. 73900/73920), or C.I. I. Quinacridone quinone pigments such as CI Pigment Orange 49 (C.I. No. 73900/73920); I. Anthraquinone pigments such as C.I. Pigment Yellow 147 (C.I. No. 60645); I. Anthanthrone pigments such as CI Pigment Red 168 (C.I. No. 59300); I. Pigment brown 25 (C.I. No. 12510), C.I. I. Pigment violet 32 (C.I. No. 12517), C.I. I. Pigment yellow 180 (C.I. No. 21290), C.I. I. Pigment yellow 181 (C.I. No. 11777), C.I. I. Pigment orange 62 (C.I. No. 11775), or C.I. I. Benzimidazolone pigments such as CI Pigment Red 185 (C.I. No. 12516); I. Pigment yellow 93 (C.I. No. 20710), C.I. I. Pigment yellow 94 (C.I. No. 20038), C.I. I. Pigment yellow 95 (C.I. No. 20034), C.I. I. Pigment yellow 128 (C.I. No. 20037), C.I. I. Pigment yellow 166 (C.I. No. 20003), C.I. I. Pigment orange 34 (C.I. No. 21115), C.I. I. Pigment orange 13 (C.I. No. 21110), C.I. I. Pigment orange 31 (C.I. No. 20050), C.I. I. Pigment red 144 (C.I. No. 20735), C.I. I. Pigment red 166 (C.I. No. 20730), C.I. I. Pigment red 220 (C.I. No. 20055), C.I. I. Pigment red 221 (C.I. No. 20065), C.I. I. Pigment red 242 (C.I. No. 20067), C.I. I. Pigment red 248M. I. Pigment red 262, or C.I. I. Disazo condensation pigments such as CI Pigment Brown 23 (C.I. No. 20060),

C. I. Pigment yellow 13 (C.I. No. 21100), C.I. I. Pigment yellow 83 (C.I. No. 21108), or C.I. I. Disazo pigments such as CI Pigment Yellow 188 (C.I. No. 21094); I. Pigment red 187 (C.I. No. 12486), C.I. I. Pigment red 170 (C.I. No. 12475), C.I. I. Pigment yellow 74 (C.I. No. 11714), C.I. I. Pigment yellow 150 (C.I. No. 48545), C.I. I. Pigment red 48 (C.I. No. 15865), C.I. I. Pigment red 53 (C.I. No. 15585), C.I. I. Pigment orange 64 (C.I. No. 12760), or C.I. I. Azo pigments such as C.I. Pigment Red 247 (C.I. No. 15915), C.I. I. Indanthrone pigments such as CI Pigment Blue 60 (C.I. No. 69800); I. Pigment green 7 (C.I. No. 74260), C.I. I. Pigment Green 36 (C.I. No. 74265), Pigment Green 37 (C.I. No. 74255), Pigment Blue 16 (C.I. No. 74100), C.I. I. Phthalocyanine pigments such as CI Pigment Blue 75 (C.I. No. 74160: 2) or 15 (C.I. No. 74160); I. Pigment blue 56 (C.I. No. 42800) or C.I. I. Triarylcarbonium pigments such as C.I. Pigment Blue 61 (C.I. No. 42765: 1); I. Pigment violet 23 (C.I. No. 51319) or C.I. I. Dioxazine pigments such as CI Pigment Violet 37 (C.I. No. 51345); I. Aminoanthraquinone pigments such as C.I. Pigment Red 177 (C.I. No. 65300); I. Pigment red 254 (C.I. No. 56110), C.I. I. Pigment Red 255 (C.I. No. 561050), C.I. I. Pigment red 264, C.I. I. Pigment red 272 (C.I. No. 561150), C.I. I. Pigment orange 71, or C.I. I. Diketopyrrolopyrrole pigments such as C.I. Pigment Orange 73; I. Thioindigo pigments such as CI Pigment Red 88 (C.I. No. 7313), CI Pigment Yellow 139 (C.I. No. 56298), C.I. I. Pigment Orange 66 (C.I. No. 48210) and the like, isoindoline pigments such as C.I. I. Pigment yellow 109 (C.I. No. 56284), or C.I. Pigment Orange 61 (C.I. No. 11295) and the like, isoindolinone pigments such as C.I. I. Pigment Orange 40 (C.I. No. 59700), or C.I. I. Pyranthrone pigments such as CI Pigment Red 216 (C.I. No. 59710), or C.I. I. And isoviolanthrone pigments such as CI Pigment Violet 31 (60010).
As the colorant, two or more kinds of organic pigments or solid solutions of organic pigments can be used in combination.

  In addition, particles having silica, alumina, resin, or the like as a core material and having a dye or pigment fixed on the surface, an insoluble raked product of a dye, a colored emulsion, a colored latex, or the like can also be used as a pigment. Furthermore, resin-coated pigments can also be used. This is called a microcapsule pigment, and commercially available products such as those manufactured by Dainippon Ink and Chemicals and Toyo Ink are available.

  The volume average particle diameter of the pigment particles contained in the liquid is preferably in the range of 10 to 250 nm, more preferably 50 to 200 nm, from the viewpoint of balance between optical density and storage stability. Here, the volume average particle diameter of the pigment particles can be measured by a particle size distribution measuring device such as LB-500 (manufactured by HORIBA).

  The colorant may be used alone or in combination of two or more. Different colorants may be used for each droplet and liquid to be ejected, or the same colorant may be used.

(Other ingredients)
In addition to the above-described components, known additives and the like can be used in combination with the ink and / or undercoat liquid depending on the purpose.

<Storage stabilizer>
A storage stabilizer is preferably added to the ink and the undercoat liquid (particularly ink) for the purpose of suppressing undesired polymerization during storage. The storage stabilizer is preferably used in combination with a polymerizable or crosslinkable material, and it is preferable to use a storage stabilizer that is soluble in the contained droplets or liquid or other coexisting components.

  Storage stabilizers include quaternary ammonium salts, hydroxylamines, cyclic amides, nitriles, substituted ureas, heterocyclic compounds, organic acids, hydroquinones, hydroquinone monoethers, organic phosphines, copper compounds, and the like. Specific examples include benzyltrimethylammonium chloride, diethylhydroxylamine, benzothiazole, 4-amino-2,2,6,6-tetramethylpiperidine, citric acid, hydroquinone monomethyl ether, hydroquinone monobutyl ether, and copper naphthenate. It is done.

  The amount of storage stabilizer added is preferably adjusted as appropriate based on the activity of the polymerization initiator, the polymerizability of the polymerisable or crosslinkable material, and the type of storage stabilizer, but the balance of storage stability and curability is balanced. In terms of solids content in the liquid, it is preferably 0.005 to 1% by mass, more preferably 0.01 to 0.5% by mass, and 0.01 to 0.2% by mass. More preferably.

<Conductive salts>
Conductive salts are solid compounds that improve conductivity. In the present invention, it is preferable not to use it substantially because there is a great concern of precipitation during storage, but it is possible to increase the solubility of conductive salts or use a highly soluble liquid component. If it is good, an appropriate amount may be added.
Examples of the conductive salts include potassium thiocyanate, lithium nitrate, ammonium thiocyanate, dimethylamine hydrochloride and the like.

<solvent>
In the present invention, a known solvent can be used as necessary. The solvent can be used for the purpose of improving the polarity and viscosity of liquid (ink), surface tension, solubility and dispersibility of coloring materials, adjusting conductivity, and adjusting printing performance.
Since the solvent is a water-insoluble liquid and does not contain an aqueous solvent, it is preferable in terms of recording a high-quality image with quick drying and uniform line width. It is desirable to do.
As the high-boiling organic solvent, those having a property excellent in compatibility with the constituent materials, particularly with the monomers are preferable.
Specifically, tripropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, ethylene glycol monobenzyl ether, diethylene glycol monobenzyl ether should be used. Is preferred.

  Known solvents include low boiling point organic solvents that are organic solvents at 100 ° C. or lower, but there is a concern of affecting the curability, and it is desirable not to use low boiling point organic solvents in consideration of environmental pollution. . When used, it is preferable to use a highly safe solvent, and a highly safe solvent is a solvent having a high management concentration (an index indicated by the work environment evaluation criteria), preferably 100 ppm or more, More preferably, it is 200 ppm or more. Specific examples include alcohols, ketones, esters, ethers, hydrocarbons, and the like, and specific examples include methanol, 2-butanol, acetone, methyl ethyl ketone, ethyl acetate, and tetrahydrofuran.

  Solvents can be used in combination other than one type alone, but when water and / or a low boiling point organic solvent is used, the amount of both used should be 0 to 20% by mass in each liquid. It is more preferable to set it as 0-10 mass%, and it is especially preferable not to contain substantially. The ink and undercoat liquid according to the present invention contain substantially no water, thereby improving the stability over time such as non-uniformity over time, turbidity of the liquid due to precipitation of dyes, etc. The drying property when using a slow-penetrating recording medium can also be improved. In addition, it does not contain substantially means accepting presence of an inevitable impurity.

<Other additives>
Furthermore, known additives such as polymers, surface tension adjusters, ultraviolet absorbers, antioxidants, anti-fading agents and pH adjusters can be used in combination.
Regarding the surface tension adjusting agent, ultraviolet absorber, antioxidant, anti-fading agent, and pH adjusting agent, known compounds may be appropriately selected and used. For example, JP-A-2001-181549 discloses a specific example. The additives described can be used.

In addition to the above, a set of compounds that react by mixing to generate aggregates or thicken can be separately contained in the ink and the undercoat liquid according to the present invention. The set of compounds has a feature of rapidly forming aggregates or rapidly thickening the liquid, thereby more effectively suppressing coalescence between adjacent droplets. Can do.
Here, examples of reaction of a set of compounds include acid / base reaction, hydrogen bond reaction by carboxylic acid / amide group-containing compound, cross-linking reaction represented by boronic acid / diol, and electrostatic interaction by cation / anion. And the like.

  Although the ink jet recording apparatus according to the present invention has been described in detail above, the present invention is not limited to the above embodiment, and various improvements and modifications are made without departing from the gist of the present invention. Also good.

  For example, as described above, since the image formed on the recording medium can have higher image quality, it is preferable to semi-cure the undercoat liquid. However, the present invention is not limited to this, and the coating was performed on the recording medium. After the undercoat liquid is completely cured, ink droplets may be ejected onto the recording medium (more precisely, the undercoat layer) to form an image, or the undercoat liquid applied onto the recording medium may be Without curing, ink droplets are ejected onto the recording medium (more precisely, the undercoat layer) to form an image, and then irradiated with actinic rays, so that the image area on the recording medium and the undercoat layer are simultaneously applied. It may be cured.

Further, the method of semi-curing the undercoat liquid (undercoat layer) and / or the ink is not limited to the above method, and a basic compound is imparted to the acidic polymer, or the acidic compound or metal is applied to the basic polymer. A method using a so-called agglomeration phenomenon, such as adding a compound, and preparing an undercoat liquid (ink) with a high viscosity in advance, adding a low boiling point organic solvent to this to lower the viscosity, and evaporating the low boiling point organic solvent The method of returning to the original high viscosity, the method of heating the undercoat liquid (ink) prepared to high viscosity and cooling it to the original high viscosity by cooling, and applying the heat to the undercoat liquid (ink) to cause the curing reaction A known thickening method, such as a method of causing it, can be mentioned.
In addition, as a method for semi-curing the undercoat liquid and the ink, it is preferable to use a method in which a curing reaction is caused by applying heat or irradiating the above-described active energy rays.

  Further, in this embodiment, an active light curable undercoat liquid and ink are used as the undercoat liquid and ink, and the undercoat liquid and ink are cured by irradiating active light. However, the present invention is not limited to this. Undercoat liquid and ink other than the actinic ray curable type may be used. For example, an image may be formed by a conventionally known means using thermosetting ink. Further, a thermosetting liquid may be used as the undercoat liquid.

  The inkjet head maintenance apparatus, inkjet head, inkjet recording apparatus, and inkjet head maintenance method according to the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments. Various improvements and changes may be made without departing from the scope of the invention.

It is a front view which shows schematic structure of an example of the digital label printing apparatus which can use the maintenance apparatus of this invention. It is a longitudinal cross-sectional view which shows the layer structure of a recording medium. It is a schematic perspective view which expands and shows the drawing part of the digital label printing apparatus shown in FIG. FIG. 4A is a side view showing a schematic configuration of a recording head, FIG. 4B is a bottom view showing an arrangement pattern of ejection portions of the recording head, and FIG. 4C is a recording head shown in FIG. It is CC sectional view taken on the line which shows schematic structure. It is a side view which shows schematic structure of the recording head and maintenance apparatus of the digital label printing apparatus shown in FIG. FIG. 6 is a partial cross-sectional view taken along the line VI-VI showing the schematic configuration of the maintenance apparatus shown in FIG. 5. It is a schematic perspective view which shows the shape of the attraction | suction member shown in FIG. (A)-(C) are sectional drawings which show the state which applied the ink droplet to the surface of undercoat liquid, respectively. The foil pressing state is shown, (A) is a cross-sectional view of the main part of the recording medium having a large unevenness on the image surface, (B) is a cross-sectional view of the main part of the recording medium pressed without smoothing, (C) is It is principal part sectional drawing of the recording medium which smoothed the unevenness | corrugation by the smoothing means, and was foil-pressed. (A) and (B) are process diagrams for explaining a maintenance method of the recording head. (A)-(E) are process drawings for demonstrating another example of the maintenance method of a recording head, respectively. FIG. 10 is a process diagram for explaining another example of a recording head maintenance method. It is sectional drawing which shows schematic structure of the other example of a maintenance apparatus. It is sectional drawing which shows schematic structure of the other example of a maintenance apparatus. (A) is a top view which shows the maintenance apparatus periphery of another example of a label printing apparatus, (B) is a front view of (A). FIG. 10 is a bottom view illustrating another example of an arrangement pattern of ejection portions of a recording head. It is a front view which shows schematic structure of the other example of the digital label printing apparatus using the maintenance apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 Ejection part 13 Head substrate 14 Ink chamber unit 16 Nozzle 16a Ejection port 18 Pressure chamber 20 Supply port 22 Common flow path 24 Actuator 26 Pressure plate 28 Individual electrode 30, 202, 220 Maintenance device 32, 204, 222 Removal mechanism 36 1st Suction member 36a Suction member 37 Second suction member 38, 39, 208, 226 Slits 40, 41, 210, 228 Connection pipe 42 Support body 44 Suction member moving mechanism 45, 45a, 212 Tube 46 Ink trap mechanism 48 Suction pump 50 Support Table 52 Drive screw 54 Guide rail 56 Coupling body 60 Ink tank 61 Supply pipe 62 Filter 64 Ink pressurizing mechanism 66 Solenoid valve 70 Liquid flow guide 100 Digital label printing apparatus 110 Conveying section 112 Drawing section 114 Maintenance section 116 Smoothing unit 118 Foil pressing unit 120 Label removing unit 121 Control unit 122 Supply roll 124, 126, 128, 130, 132 Pair of conveying rollers 134 Product winding unit 135 Recording head unit 136M, 136C, 136Y, 136K Recording head (inkjet head) )
137 Ink storage / loading unit 138 Ultraviolet irradiation unit 142 Varnish coater 144, 145 Application roller 146 Flat pressure member 148 Ultraviolet irradiation unit 150 Foil supply roll 152 Foil winding roll 154, 156 Roller 158 Foil 160 Hot stamp plate 162 Varnish coater 164 Ultraviolet irradiation Part 166 Die cutter 168 Cylinder cutter 170 Receiving roller 172 Waste removal part 206, 224 Blowout member 214 Blowout pump

Claims (18)

A maintenance device for an inkjet head in which a plurality of ejection openings for ejecting ink droplets are formed in a row on a head substrate,
The surface of the head substrate facing the surface on which the discharge port is formed and not contacting the head substrate is disposed on the surface of the head substrate facing the surface on which the discharge port is formed. At least one first suction port whose longitudinal direction is a direction parallel to the arrangement direction of the outlets and at least one second suction port whose longitudinal direction is a direction parallel to the arrangement direction of the discharge ports are the discharge ports. A removal unit comprising suction members opened in parallel and spaced apart from each other in a direction orthogonal to the arrangement direction;
An inkjet head maintenance device comprising: a suction pump for sucking air in the suction member.   The inkjet head maintenance device according to claim 1, wherein the suction member includes a first suction member in which the first suction port is formed and a second suction member in which the second suction port is formed.   In the suction member, an opening diameter of the discharge port in a direction orthogonal to the arrangement direction of the discharge ports is R [mm], and a size of the suction port in a direction orthogonal to the arrangement direction of the discharge ports is L [mm]. Then, the maintenance device according to claim 1 or 2, wherein an interval between the first suction port and the second suction port in a direction orthogonal to the arrangement direction of the discharge ports is equal to or less than (R + L + 2) [mm]. The first suction port of the suction member is disposed at a position facing one end of the discharge port in a direction orthogonal to the arrangement direction of the discharge ports,
The said 2nd suction port of the said suction member is arrange | positioned in the position which opposes the other edge part of the said discharge port in the direction orthogonal to the arrangement direction of the said discharge port. Inkjet head maintenance device. The removal unit is further disposed adjacent to the suction member, and a direction parallel to the arrangement direction of the ejection ports of the inkjet head is arranged on a surface of the head substrate facing the surface where the ejection ports are formed. A blow-out member having at least one blow-out opening in the longitudinal direction opened;
Furthermore, the maintenance apparatus of the inkjet head in any one of Claims 1-4 which has a blowing pump which supplies air to the said blowing member.   The inkjet head maintenance according to claim 5, wherein the blowout port of the blowout member is disposed between the first suction port and the second suction port in a direction orthogonal to the arrangement direction of the discharge ports. apparatus. A maintenance device for an inkjet head in which a plurality of ejection openings for ejecting ink droplets are formed in a row on a head substrate,
The ink jet is disposed on a surface of the head substrate facing the surface on which the ejection port is formed and not contacting the head substrate, and facing the surface on which the ejection port of the head substrate is formed. A suction member having at least one suction port having a longitudinal direction parallel to the arrangement direction of the ejection ports of the head as a longitudinal direction and the suction member of the head substrate are formed adjacent to the suction member. A removal unit comprising a blowing member having at least one blower outlet having a longitudinal direction parallel to the arrangement direction of the discharge ports of the inkjet head as a longitudinal direction on a surface opposed to the surface being formed;
A suction pump for sucking air in the suction member;
An ink jet head maintenance device comprising: a blow pump for supplying air to the blow member.   The inkjet head maintenance according to any one of claims 1 to 7, wherein the suction port and the blow-out port have a length in the arrangement direction of the discharge ports longer than an arrangement interval of the discharge ports arranged in a row. apparatus.   Furthermore, it has an immersion mechanism which discharges ink from the discharge port of the inkjet head and wets the surface of the head substrate on which the discharge port is formed with ink when the suction pump is stopped. An inkjet head maintenance apparatus according to claim 1.   The dipping mechanism is further disposed at a position facing the surface of the head substrate where the discharge port is formed and not contacting the head substrate, and the surface of the head substrate where the discharge port is formed; The ink jet head maintenance apparatus according to claim 9, further comprising a liquid flow guide that forms a flow path for ink discharged from the ink jet head.   Furthermore, it has a removal unit attachment / detachment mechanism which moves the said removal unit to the direction orthogonal to the surface in which the said discharge port of the said head substrate is formed at the time of the said suction pump pause. Inkjet head maintenance device.   The inkjet head maintenance device according to claim 1, wherein the suction member includes a plurality of the first suction ports and a plurality of the second suction ports that are opened in series in the arrangement direction of the discharge ports. A droplet discharge unit in which a plurality of discharge ports for discharging ink droplets are formed in a line on the head substrate;
The surface of the head substrate facing the surface on which the ejection port is formed and not in contact with the head substrate, the surface of the head substrate facing the surface on which the ejection port is formed, At least one first suction port whose longitudinal direction is a direction parallel to the arrangement direction of the discharge ports and at least one second suction port whose longitudinal direction is a direction parallel to the arrangement direction of the discharge ports are the discharge ports. A removal unit comprising suction members spaced apart and opened in parallel in a direction perpendicular to the arrangement direction of the outlets;
An ink jet head having a suction pump for sucking air in the suction member. A droplet discharge unit in which a plurality of discharge ports for discharging ink droplets are formed in a line on the head substrate;
The liquid is disposed on a surface of the head substrate facing the surface on which the discharge ports are formed and not in contact with the head substrate, and facing the surface of the head substrate on which the discharge ports are formed. A suction member having at least one suction port whose longitudinal direction is parallel to the arrangement direction of the discharge ports of the droplet discharge unit, and the discharge port of the head substrate, which is disposed adjacent to the suction member. A removal unit comprising a blowing member having a surface opposite to the surface on which is formed, at least one outlet having a longitudinal direction parallel to the direction of arrangement of the discharge ports of the droplet discharge unit as a longitudinal direction;
A suction pump for sucking air in the suction member;
An ink jet head having a blow pump for supplying air to the blow member. An inkjet head in which a plurality of ejection openings for ejecting ink droplets are formed in a row on a head substrate;
The surface of the head substrate facing the surface where the discharge port is formed and not contacting the head substrate, and the surface of the head substrate facing the surface where the discharge port is formed, At least one first suction port whose longitudinal direction is parallel to the array direction of the discharge ports and at least one second suction port whose longitudinal direction is the direction parallel to the array direction of the discharge ports are the discharge ports A removal unit comprising suction members that are spaced apart from each other in the direction orthogonal to the arrangement direction of
An ink jet recording apparatus having a suction pump for sucking air in the suction member. An inkjet head in which a plurality of ejection openings for ejecting ink droplets are formed in a row on a head substrate;
The inkjet head is disposed on a surface of the head substrate that faces the surface on which the ejection ports are formed and that does not contact the head substrate, and that faces the surface on which the ejection ports are formed. A suction member having at least one suction port whose longitudinal direction is parallel to the direction in which the discharge ports are arranged, and the suction member disposed adjacent to the suction member to form the discharge port of the head substrate. A removal unit comprising a blowing member having at least one blower outlet having a longitudinal direction parallel to the arrangement direction of the discharge ports of the inkjet head as a longitudinal direction on a surface facing the surface of the inkjet head;
A suction pump for sucking air in the suction member;
An ink jet recording apparatus comprising: a blow pump for supplying air to the blow member. A maintenance method for an inkjet head in which a plurality of ejection openings for ejecting ink droplets are formed in a row on a head substrate,
Discharging ink from the discharge port, wetting the surface of the head substrate on which the discharge port is formed with the ink,
There is a suction port whose longitudinal direction is the arrangement direction of the discharge ports, and a suction member that sucks air from the suction port does not contact a plurality of the discharge ports on the surface of the head substrate on which the discharge ports are formed Close to the position,
An inkjet head maintenance method for sucking at least one of air and ink from the suction port and sucking deposits around the discharge port of the head substrate. Further, at the same time as the suction member, there is a blower outlet in which the arrangement direction of the discharge outlets is the longitudinal direction, and a blower member for injecting air from the blower outlet is formed on the surface on which the discharge outlet of the head substrate is formed. Proximity to a position that does not contact a plurality of the discharge ports,
18. The inkjet according to claim 17, wherein air is ejected from the air outlet to the vicinity of the discharge port, and at least one of air and ink is sucked from the suction port to suck the deposit around the discharge port of the head substrate. Head maintenance method.

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