JP2008246728A - Maintenance device of inkjet head, inkjet head assembly, inkjet recorder equipped with this and maintenance method of inkjet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a gap of a placement position of an inkjet head unit at the time of maintenance of an inkjet head in which a plurality of the inkjet head units each with a plurality of ejection ports for ejecting ink liquid droplets formed in an array shape in an ejection port plate are arranged at a supporting frame with an arrangement direction of the ejection ports agreed with each other. <P>SOLUTION: The maintenance device of the inkjet head has at least two sheets of guide members set at the supporting frame to be disposed at both sides holding each inkjet head unit of a plurality of the inkjet head units between, having end faces in parallel to a face where the ejection ports of the ejection port plate are formed; a suction member opposed to the ejection face of the ejection port plate of each inkjet head unit; and a butting member formed to the suction member to arrange a suction opening of the suction member at a position where it contacts with the end faces of the guide members to be opposed and non-contact to the ejection face. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to the field of maintenance of 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, and an inkjet head assembly having the maintenance device In addition, the present invention relates to an inkjet recording 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 discharges ink droplets from such discharge ports, ink droplets may adhere to the surface of the nozzle plate on which the discharge ports (nozzles) are formed.
When such ink droplets adhere to the discharge port substrate, particularly around the discharge port, there is a problem that the ink discharge 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 liquid repellent, The above-described method using a blade or an absorbent body that is in contact with the surface 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 nozzle plate, 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 openings of the local suction means are arranged in a nozzle arrangement. An ink jet head maintenance device is described that includes a suction opening moving means for relatively moving in a direction. In Patent Document 1, this local suction means is held by a positioning guide, and the suction openings are relatively moved in the nozzle arrangement direction with the positioning guide positioning the local suction means with respect to the head body. It is also described.

Also, in Patent 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 Patent Document 1 and Patent Document 2, it is possible to prevent the nozzle plate surface from being damaged during maintenance by performing suction from a position spaced apart from the nozzle plate by a certain distance.

  However, the maintenance device for the inkjet head described in Patent 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.

In addition, the maintenance device for an inkjet head described in Patent Document 1 positions a local suction unit with respect to the head body by bringing a positioning guide into contact with the head body. Thereby, the installation position of the head body may change.
In FIG. 25A, head units 302A, 302B, and 302C having nozzles (ejection ports) 304 arranged in one direction are arranged so that the arrangement directions of the nozzles are parallel to each other. An inkjet head 300 configured to be able to record corresponding to the entire area of one side is shown. The ink jet head 300 is used in a state where the position of each head unit is adjusted so that the intervals between the droplet ejection points are uniform.
Here, when the local suction means is brought into contact with the head unit and positioned with respect to the head unit during maintenance, the position of each head unit may change. As shown in FIG. 25B, the nozzle interval between the head units 302 adjacent in the nozzle arrangement direction (for example, the interval in the nozzle arrangement direction of nozzle A5 and nozzle B1 in FIG. 25B) is the same. The value is different from the nozzle interval in each of the head units 302A, 302B, and 302C. When drawing in such a state, there is a problem that unevenness occurs in the image.

  In addition, when each of the plurality of head units is disposed on a support plate or the like via a head alignment adjustment mechanism for adjusting the position of the head unit, adjustment and correction of the position of the head unit can be easily performed. it can. However, as in Patent Document 1, when the positioning guide is brought into contact with the head body, that is, when the local suction unit is positioned with respect to each of the head units having the head alignment adjustment mechanism, the head by the head alignment adjustment mechanism There is a problem that the installation position of each head unit may be shifted due to the influence of the variation in unit installation position stability, and streaks are likely to occur in the recorded image. In order to prevent such a problem, if the installation position stability of the head of the head alignment adjustment mechanism is improved, there is a problem that the apparatus configuration becomes complicated or the apparatus becomes expensive.

Further, in the ink ejecting apparatus described in the cited document 2, there is no description about problems when a plurality of nozzles (ejection ports) are formed.
Here, for example, when one cap is arranged for a plurality of nozzles, there is a problem that ink between adjacent nozzles may remain on the nozzle plate.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems based on the above prior art, and even if an ink jet head is configured by arranging a plurality of head units, the ink jet head without changing the positional relationship between the head units. It is an object to provide an inkjet maintenance device, an inkjet head, an inkjet recording device, and an inkjet maintenance method capable of performing maintenance.
Another object of the present invention is to provide an inkjet head maintenance device, an inkjet head, an inkjet recording device, and an inkjet that can perform maintenance of the inkjet head efficiently, in a short time, and without damaging the nozzle plate. To provide a maintenance method.

In order to solve the above-described problems and achieve the object of the present invention, a first aspect of the present invention includes a plurality of ejection openings, each of which ejects ink droplets, formed in a row on an ejection outlet plate. An inkjet head maintenance device disposed on a support frame by an alignment adjustment mechanism that adjusts a relative position between the plurality of inkjet head units, wherein the head unit is aligned with the arrangement direction of the ejection ports,
In the direction orthogonal to the arrangement direction, each inkjet head unit of the plurality of inkjet head units is sandwiched and disposed on both sides thereof, and the ejection port of the ejection port plate is formed on the support frame. At least two guide members having end faces parallel to the surface being
A suction member formed with at least one suction port facing the surface of the ejection port plate of each inkjet head unit on which the ejection port is formed, and provided on the suction member and adjusted by the alignment adjusting mechanism. Further, the surface of the discharge port plate is opposed to the surface on which the discharge port is formed in contact with the end surfaces of the guide members on both sides of each of the inkjet head units so that the relative position between the plurality of inkjet head units does not change. And the abutting member which arrange | positions the said suction opening of the said suction member in the position which becomes non-contact, the said abutting member is made to slide-contact with the said end surface of the said guide member of the both sides, and the said suction opening is said discharge outlet A removal unit comprising a moving mechanism for moving the plate in parallel with the surface on which the discharge port is formed, and
The present invention provides a maintenance device for an ink-jet head having a suction pump for sucking air in the suction member.

In the first aspect of the present invention, the suction port is an opening whose longitudinal direction is the arrangement direction of the discharge ports, and the moving mechanism moves the suction port in a direction orthogonal to the arrangement direction of the discharge ports. Preferably, the moving mechanism moves the suction port a distance longer than at least the size of the discharge port in a direction orthogonal to the arrangement direction of the discharge ports.
Alternatively, in the first aspect of the present invention, the suction port is an opening corresponding to at least one region of the discharge port, and the moving mechanism moves the suction member in the arrangement direction of the discharge port. The abutting member is preferably formed integrally with the suction member.

  Further, in the first aspect of the present invention, it is preferable that the apparatus further comprises means for discharging ink from the discharge port and wetting the surface of the discharge port plate on which the discharge port is formed with ink. The means for wetting is further discharged from the ink jet head between the surface of the discharge port plate facing the surface where the discharge port is formed and the surface of the discharge port plate where the discharge port is formed. It is preferable to have a liquid flow guide that forms an ink flow path, and the liquid flow guide extends along at least one end of the suction port in the moving direction of the suction port of the moving mechanism. It is preferable to be disposed.

  In the first aspect of the present invention, it is preferable that the removal unit further includes a removal unit moving unit that moves the removal unit in a direction orthogonal to a surface of the discharge port plate on which the discharge port is formed.

According to a second aspect of the present invention, there are provided a discharge port plate in which a plurality of discharge ports for discharging ink droplets are formed in a row, and each of the plurality of discharge ports. An inkjet including a plurality of inkjet head units, and a support frame in which the plurality of inkjet head units are arranged with the arrangement direction of the ejection ports aligned. Head,
An ink jet head assembly comprising the ink jet head maintenance apparatus according to the first aspect of the present invention is provided.

According to a third aspect of the present invention, there is provided an inkjet head assembly according to the second aspect of the present invention,
Relative moving means for moving a recording medium for discharging the ink droplets from the plurality of discharge ports of the plurality of ink jet heads of the ink jet head assembly relative to the ink jet head assembly. An ink jet recording apparatus is provided.

According to a fourth aspect of the present invention, each of the plurality of inkjet head units in which a plurality of ejection openings for ejecting ink droplets are formed in a line on the ejection opening plate is arranged to match the arrangement direction of the ejection openings. A maintenance method for an inkjet head disposed on a support frame by an alignment adjustment mechanism that adjusts a relative position between the plurality of inkjet head units,
Discharging ink from the discharge port, wetting the surface of the discharge port plate on which the discharge port is formed with the ink,
Between the plurality of head units adjusted by the alignment adjusting mechanism, abutment member provided on a suction member in which at least one suction port facing the surface on which the discharge port is formed of the discharge port plate is formed. The suction port is brought into contact with a guide member provided on the support frame and having an end surface parallel to the surface on which the discharge port is formed so that the relative position of the discharge port plate does not change. Opposite to the surface where the outlet is formed and close to a non-contact position,
The present invention provides a maintenance method for an inkjet head in which at least one of air and ink is sucked from the suction port and is moved in parallel with the surface of the discharge port plate on which the discharge port is formed.

In the fourth aspect of the present invention, it is preferable that the suction port is an opening whose longitudinal direction is an arrangement direction of the discharge ports, and the suction port is moved in a direction orthogonal to the arrangement direction of the discharge ports.
Alternatively, in the fourth aspect of the present invention, it is preferable that the suction port is an opening corresponding to at least one region of the discharge ports, and the suction member is moved in the arrangement direction of the discharge ports.

According to the present invention, the guide member provided on the support frame and the abutting member provided on the suction member are brought into contact with each other so as to face the surface on which the discharge port of the head unit is formed and to be non-contact. By disposing the suction port of the suction member at the position where it becomes, the ink droplets around the ejection port on the surface on which the ejection port of the head substrate is formed, and dirt such as fixed matter are sucked without contacting the head unit. Thus, maintenance of the recording head can be performed.
Thereby, the positional deviation of the head unit due to maintenance can be prevented, and the drawing performance of the recording head can be maintained in a good state.

  An ink jet head maintenance apparatus according to a first aspect of the present invention, an ink jet head assembly according to a second aspect, an ink jet recording apparatus according to a third aspect, and an ink jet head maintenance method according to a fourth aspect are attached. This will be described in detail based on the embodiment shown in the drawings.

First, a digital label printing apparatus using the ink jet recording apparatus according to the third aspect of the present invention provided with the ink jet head maintenance apparatus according to the first aspect of the present invention will be described.
FIG. 1 is a schematic configuration diagram showing an embodiment of a digital label printing apparatus 100, and FIG. 2 is a longitudinal sectional view of an example of a recording medium for label printing used in the digital label printing apparatus 100 shown in FIG. 3 is a schematic perspective view showing the drawing unit 112 of the digital label printing apparatus 100 shown in FIG. 1 in an enlarged manner.

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, the foil press printing is, for example, a method in which a foil such as a gold foil, a silver foil, or a color foil is pressed against a mating member with a heated letterpress on a cover or spine of a book and the foil is thermocompression-bonded (foil-pressed). 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 pressing 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 for label printing (hereinafter referred to as “recording medium”) P in a certain direction (from left to right in FIG. 1). The section 111, the drawing section 112, the smoothing section 116, the foil pressing section 118, and the label removing section 120 are arranged along the transport direction of the recording medium P, that is, from the upstream to the downstream direction, from the undercoat section 111, the drawing section 112, The smoothing unit 116, the foil pressing unit 118, and the label removing unit 120 are arranged in this order. In addition, a maintenance unit 114 that is a characteristic part of the present invention is arranged at a position of the drawing unit 112 facing 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 laminated and bonded onto a release paper 182 as a mount. It is.

The conveyance unit 110 includes a supply roll 122, conveyance roller pairs 124, 126, 128, 130, and 132, and a product winding unit 134.
The 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 rotated by a conveyance motor (not shown), and the recording medium P is fed out 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 arranged 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, and the drawing unit 112, the smoothing unit 116, the foil pressing unit 118, and The recording medium P that has passed through the label removing unit 120 is taken up.

  The undercoat unit 111 includes an application roll 202 that applies the undercoat liquid to the recording medium P, a driving unit 204 that rotates the application roll 202, a blade 206 that adjusts the amount of the undercoat liquid that adheres to the application roll 202, and an application roll. The undercoat liquid is applied to a positioning portion 210 that supports the recording medium P so that the recording medium P is positioned at a predetermined position, and an undercoat liquid layer (hereinafter also referred to as an undercoat layer) is formed. An undercoat liquid semi-curing portion 216 that irradiates the recording medium P with ultraviolet rays to make the undercoat liquid (undercoat layer) semi-cured;

The coating roll 202 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 coating roll 202 is a roll wider 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 202 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 204 is connected to the application roll 202 and rotates the application roll 202 in a direction opposite to the conveyance direction of the recording medium P (clockwise in FIG. 1).
The driving method by the driving unit 204 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 206 is disposed in contact with the surface of the coating roll 202 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 208”) formed in an upper portion of a contact portion (contact portion) between the coating roll 202 and the blade 206. The reservoir 208 is supplied with an undercoat liquid from a supply tank (not shown) as necessary.
Accordingly, the application roll 202 is immersed in the undercoat liquid in the storage unit 208 and is in contact with the recording medium P.
The blade 206 immerses the coating roll 202 in the storage unit 208 to scrape off the undercoating liquid adhering more than necessary from the adhering undercoating liquid, so that the amount of the undercoating liquid adhering to the coating roll 202 is fixed. . Specifically, the blade 206 scrapes off the undercoat liquid adhering to other parts of the application roll 202 except for the undercoat liquid held in the recesses formed on the surface of the application roll 202.
As a result, the undercoat liquid held in the portion of the coating roll 202 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 210 includes positioning rolls 212 and 214, and supports the recording medium P so that the recording medium P at a position in contact with the application roll 202 is at a predetermined position. That is, the positioning unit 210 sets the transport path of the recording medium P at a position where the coating roll 202 and the recording medium P are in contact with each other to a predetermined position.
The positioning roll 212 is on the surface (hereinafter also referred to as the back 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 the transport direction of the recording medium P In FIG. 2, it is disposed between the conveying roller pair 124 and the coating roll 202.
The positioning roll 214 is disposed on the back side of the recording medium P and between the coating roll 202 and an undercoat liquid semi-curing portion 216 described later in the conveyance direction of the recording medium P.
That is, the positioning rolls 212 and 214 are sandwiched between the coating roll 202 in the conveyance direction of the recording medium P on the opposite side of the coating roll 202 via the recording medium P, that is, upstream of the coating roll 202. Are arranged on the downstream side.
The positioning rolls 212 and 214 support the recording medium P from the back surface of the recording medium P.

The undercoat unit 111 has the above-described configuration, and the drive unit 204 rotates the application roll 202 in the direction opposite to the conveyance direction of the recording medium P. The surface of the rotating coating roll 202 is immersed in the undercoat liquid stored in the storage unit 208, and then comes into contact with the blade 206. 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. In this way, by applying the undercoat liquid to the recording medium P by rotating the coating roll 202 in the direction opposite to the conveyance direction of the recording medium P, the coating roll 202 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 202 that has come into contact with the recording medium P further rotates and is immersed again in the undercoat liquid of the storage unit 208.
In this way, the undercoat unit 111 rotates the application roll 202 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, the undercoat layer U with improved surface shape can be formed on the recording medium P by rotating the coating roll 202 in the direction opposite to the conveyance direction of 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 unit 216 includes 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 216 irradiates the entire area in the width direction of the recording medium P passing through the opposing position with ultraviolet rays.

  The undercoat liquid semi-curing unit 216 irradiates the recording medium P with the undercoat liquid applied to the surface passing through the opposing position, and puts the undercoat liquid applied on the surface of the recording medium P into a semi-cured state. To do. That is, the undercoat liquid semi-curing unit 216 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”) 136W, 136C, 136M, 136Y, and 136K, and discharges ink droplets at positions facing the conveyance path of the recording medium P. The leading end of the ejecting section is disposed to face the recording medium P.

The recording heads 136W, 136C, 136M, 136Y, and 136K are ink jet heads that discharge white (W), cyan (C), magenta (M), yellow (Y), and black (K) ink from the discharge unit, respectively. The recording head 136W, the recording head 136C, the recording head 136M, the recording head 136Y, and the recording head 136K are arranged in this order from upstream to downstream in the conveyance direction of the recording medium P. The recording heads 136 </ b> W, 136 </ b> C, 136 </ b> M, 136 </ b> Y, and 136 </ b> K are connected to the ink storage / loading unit 137 and the control unit 121.
The recording heads 136W, 136C, 136M, 136Y and 136K have a plurality of ejection portions (nozzles) up to 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 inkjet head arranged. 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 136W, 136C, 136M, 136Y 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 136W, 136C, 136M, 136Y, 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 136W, 136C, 136M, 136Y, and 136K via a pipe line (not shown), and each recording head 136W, 136C, 136M, 136Y, and 136K. Ink is supplied.

The ultraviolet irradiation unit 138 includes an active energy ray irradiation light source, and is disposed on the downstream side of each recording head 136W, 136C, 136M, 136Y, and 136K corresponding to each recording head 136W, 136C, 136M, 136Y, and 136K. Has been. 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.
Each ultraviolet irradiation unit 138 passes the recording heads 136W, 136C, 136M, 136Y, and 136K, and irradiates the recording medium P on which an image is formed with ultraviolet rays. That is, each 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, each ultraviolet irradiation unit 138 irradiates the ink on the recording medium P with the emitted ultraviolet rays and does not irradiate the ink ejection ports of the recording heads 136W, 136C, 136M, 136Y, and 136K. A configuration is preferable. In this way, by preventing the ink discharge port from being irradiated with ultraviolet rays, it is possible to prevent the ink of each color from being cured at the discharge 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 136W, 136C, 136M, 136Y, 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 transparent active energy rays (ultraviolet rays in the present embodiment) curable liquid (on the present embodiment). Hereinafter, the varnish coater 142 which is a transparent liquid supply means for supplying “active energy ray-curable transparent liquid” or simply “transparent liquid”) and a foil supply range described later of the recording medium P are pressed smoothly. A flat pressure member 146 that performs the irradiation, and an ultraviolet irradiation unit 148 that is an active energy ray irradiating 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, a fluorescent lamp, 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 should be 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 stamping plate 160 is in a state in which the recording medium P is stopped in contact with the recording medium P through the foil 158 while the conveyance of the recording medium P is stopped. According to the shape, the foil 158 is heat-pressed on the recording medium P, that is, a foil pressing process is performed. When the foil pressing is completed, the recording medium P is conveyed until the area of the recording medium P to be subjected to the foil pressing process reaches a position facing the relief plate 160a. That is, the recording medium P is intermittently conveyed at the foil pressing unit 116.

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, a continuous paper-like shape caused by a difference in transport speed between the smoothing unit 116 disposed upstream of the foil pressing unit 118 and the foil pressing unit 118 that intermittently transports the recording medium P and performs foil pressing. The slack of the recording medium P can be absorbed, and the label can be manufactured 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 irradiating unit 164 for improving gloss by being applied to the substrate, a die cutter 166 for making a label-like 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 application rolls with UV-curing transparent liquid adhered (impregnated) on the surface thereof, and supports the movement of the recording medium P (synchronously) 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), and cures 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 surface can be protected. 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 136W, 136C, 136M, 136Y, and 136K will be described in detail. Here, since the recording heads 136W, 136C, 136M, 136Y, 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 front view showing a schematic configuration of the recording head 136K, and FIG. 4B is a cross-sectional view taken along line BB of FIG. 4A.
As shown in these drawings, the recording head 136K includes a plurality of inkjet head units (hereinafter referred to as head units) 70, a support frame 72, and an alignment adjustment mechanism 74, and each head unit 70 has an alignment adjustment mechanism. 74 is disposed on the support frame 72 via 74. In the present embodiment, the recording head 136K has four head units 70.
The head unit 70 ejects ink droplets from the tip openings 16a of the plurality of nozzles 16 arranged in one direction, and details will be described later.

The support frame 72 is disposed to face the recording medium conveyance path with the direction orthogonal to the recording medium conveyance direction (that is, the width direction of the recording medium) as the longitudinal direction, and includes a plurality of head units 70 (this embodiment). In the embodiment, the four head units 70) are members that support the recording medium toward the conveyance path.
The support frame 72 includes flat plate members 72a, 72b and 72c arranged in three rows parallel to the longitudinal direction so as to form two parallel groove portions 76 and 77, and these flat plate members 72a, 72b and A plate-like support member 72d for fixing one end surface in the width direction of 72c and side surface fixing members 72e and 72f for fixing both end surfaces in the longitudinal direction of the plate-like members 72a, 72b and 72c are provided. The flat plate member 72b is disposed as a partition wall separating the two groove portions 76 and 77 in parallel between the flat plate members 72a and 72c. In the illustrated example, the thickness is thinner than the flat plate members 72a and 72c. ing.

  In the two grooves 76 and 77 formed by the flat members 72a, 72b, and 72c, the four head units 70 are attached to the plate-like support member 72d via the alignment adjusting mechanism 74, respectively. In these two grooves 76 and 77, the four head units 70 are arranged in the direction in which the nozzles 16 (tip openings 16a) are arranged (hereinafter also referred to as arrangement direction) and in the longitudinal direction of the support frame 72 (grooves 76). , 77 in the longitudinal direction of the support frame 72, and the groove portions 76 and 77 are alternately arranged. In the illustrated example, one end of the head unit 70 disposed in the groove 76 and the other end of the head unit 70 disposed in the adjacent groove 78 partially overlap in the longitudinal direction. Placed in.

Here, the alignment adjustment mechanism 74 adjusts the relative position between the plurality of head units 70 by fixing the head unit 70 after adjusting the position and / or angle of the head unit 70. The alignment adjustment mechanism 74 adjusts the relative position between the plurality of head units 70 to adjust the ink droplet ejection position in the nozzle arrangement direction, that is, performs alignment adjustment. The alignment adjustment mechanism 74 may be one that manually adjusts the position of the head unit 70 or may be one that automatically.
As such an alignment adjusting mechanism 74, for example, the head unit 70 is pivotally supported on a pedestal arranged for each head unit 70 so that the angle can be changed, and the pedestal is arranged in a direction or arrangement by a moving means using a ball screw or the like. Although the thing arrange | positioned at the support frame so that a movement in the direction orthogonal to a direction is possible is mentioned, it is not limited to this, Various mechanisms can be used.

The flat members 72a, 72b, and 72c of the support frame 72 are respectively provided with guide members 78 on the end surface on the transport path side of the recording medium.
The guide member 78 is a plate-like member extending in a direction parallel to the arrangement direction of the tip openings 16a of the head unit 70 and perpendicular to the surface (discharge surface) on which the tip openings 16a of the nozzle plate 14 are formed. . In the illustrated example, the three guide members 78 are disposed on both sides of the head unit with the head unit 70 sandwiched in the arrangement direction of the tip openings 16a. Further, the end surface 79 of the guide member 78 on the side opposite to the support frame 72 is parallel to the surface of the head unit 70 where the tip opening 16a is formed. Moreover, each guide member 78 is comprised so that each end surface 79 may be located on the same plane.
In the present embodiment, the end surface 79 of the guide member 78 protrudes closer to the transport path than the ejection surface of the head unit 70.
The guide member 78 comes into contact with an abutting member of a removing unit of the maintenance device 30 described later. This point will be described later.

  The recording head 136K configured in this manner has the arrangement direction of the leading end openings 16a of the head unit 70 aligned with the width direction of the recording medium, and the surface on the side where the leading end openings 16a of the head unit 70 are formed is the recording medium. It is arranged toward the transport path.

By arranging the plurality of head units 70 alternately in two rows as in this embodiment, even when the plurality of head units 70 are arranged, the intervals between all the tip openings are made substantially uniform in the arrangement direction of the tip openings. be able to.
Further, in the present embodiment, as described above, the head unit 70 is arranged via the head alignment adjustment mechanism 74 to adjust the position of the head unit 70 so that the head units 70 are adjacent in the arrangement direction. Even at the boundary of the head unit 70, the interval between the tip openings can be made substantially uniform.

  In the present embodiment, the recording head 136K has the head units 70 arranged alternately in the two rows of grooves. However, the present invention is not limited to this, and the head units may be arranged over a plurality of rows of three or more. A plurality of head units may be arranged in a row.

  5A is a side view illustrating a schematic configuration of the head unit 70 of the recording head 136K, and FIG. 5B is a bottom view illustrating an arrangement pattern of the ejection units 12 of the head unit 70. (C) is CC sectional view taken on the line which shows schematic structure of the discharge part of the head unit 70 of FIG. 5 (A).

As shown in FIGS. 5A and 5B, the head unit 70 includes a head substrate 13 and a nozzle plate 14, and a plurality of ejection units 12 (tip openings 16a) for ejecting ink droplets are arranged at regular intervals. It is formed in a row. Here, each of the head substrate 13 and the nozzle plate 14 is a plate-like member common to the plurality of ejection units 12. The head substrate 13 is formed with a plurality of actuators 24 (see FIG. 5C) serving as ejection means for ejecting ink droplets, and the nozzle plate 14 corresponds to each of the plurality of actuators 24 on the head substrate 13. A plurality of tip openings (hereinafter also referred to as nozzles) 16 are formed. The nozzle plate 14 is attached on the head substrate 13 by pasting or the like so that the plurality of nozzles 16 correspond to the plurality of actuators 24 of the head substrate 13 respectively.
As the head substrate 13 and the nozzle plate 14, various materials such as a resin material, a polymer material, glass, and silicon can be used.

Hereinafter, one discharge unit 12 will be described.
As shown in FIG. 5C, the discharge unit 12 has a common flow path 22 and an actuator 24 common to the plurality of discharge units 12 formed on the head substrate 13, and a surface of the nozzle plate 14 corresponding to the actuator 24. The nozzle 16 is formed and communicates with the tip opening 16a facing the recording medium P.

As shown in FIG. 5C, the nozzle 16 is a tubular member that discharges ink droplets corresponding to the actuator 24 of the head substrate 13, and one opening is formed on the surface of the head substrate 13, and recording is performed. Opposite to the medium P, the other opening is connected to the common flow path 22. An opening formed on the surface of the head substrate 13 of the nozzle 16 is a tip opening 16a.
The nozzle 16 has a shape that a part of the tip opening 16a side becomes smaller in diameter toward the tip opening 16a.
As shown in FIG. 5A, the common flow path 22 is formed inside the head substrate 13 and is connected to the nozzles 16 of the plurality of ejection units 12 and is also connected to the ink tank 60 via the supply pipe 61. is doing.

Next, the actuator 24 is disposed on the head substrate 13 at a position facing the tip opening 16 a of the nozzle 16, and includes a pressure plate 26 and an individual electrode 28.
The actuator 24 applies a driving voltage to the individual electrode 28, whereby the pressure plate 26 is deformed, and the ink in the nozzle 16 is ejected as ink droplets from the tip opening 16a.

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 is filled in the nozzle 16.
When a drive voltage is applied to the individual electrode 28 while the nozzle 16 is filled with ink, the pressure plate 26 is deformed, the ink of the nozzle 16 is pressurized, and the ink is ejected from the tip opening 16a of the nozzle 16. Is done. That is, by driving the actuator 24, ink droplets are ejected from the tip opening 16a of the nozzle 16.
When ink droplets are ejected from the nozzle 16, negative pressure is generated in the nozzle 16, and ink is supplied from the common flow path 22.
As described above, the drawing unit 112 forms an image on the recording medium P by ejecting ink droplets from the tip opening 16 a of the nozzle 16.

  In the head unit 70, the nozzle 16 and the common flow path 22 are directly connected, and the actuator 24 is disposed in the nozzle 16. However, the present invention is not limited to this. For example, in the head unit, a nozzle and a common flow path are connected via a pressure chamber, an actuator is disposed in the pressure chamber, and the ink in the nozzle is added by pressurizing the nozzle and the ink in the pressure chamber with the actuator. The ink droplets may be discharged from the opening at the tip.

Next, the maintenance unit 114 will be described in detail.
FIG. 6 is a side view showing a schematic configuration of the head unit 70 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. 7 shows the maintenance device shown in FIG. FIG. 8 is a partial cross-sectional view taken along the line VII-VII showing a schematic configuration of FIG. 30, and FIG.

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 136W, 136C, 136M, 136Y, 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. 6, the maintenance device 30 is disposed so as to face a surface (hereinafter also referred to as “the discharge surface of the nozzle plate 14”) in which the tip opening 16 a of the nozzle plate 14 of the head unit 70 is formed. Yes. That is, the maintenance device 30 is disposed on the transport path side of the recording medium P of the recording head 136K.
Further, the maintenance device 30 has an arrangement direction of the plurality of tip openings 16a formed in the nozzle plate 14, that is, a length in a direction parallel to a line connecting the plurality of tip openings 16a formed in a row. The length is substantially the same as the length of the nozzle plate 14 or longer than the length of the nozzle plate 14. That is, the maintenance device 30 is formed with a length corresponding to all the ejection units 12 of the head unit 70.

As shown in FIG. 7, the maintenance device 30 includes a removing unit 32 and a removing mechanism moving unit 34.
The removing unit 32 includes a suction member 36, a support 42, a suction member moving mechanism 44, an ink trap 46, a suction pump 48, and an abutting member 80.

As shown in FIG. 7, the suction member 36 is disposed at a position facing the discharge unit 12 of the head unit 70 and not in contact with (no contact with) the nozzle plate 14, and a part on the discharge unit 12 side. Is a hollow box shape whose width decreases as it goes toward the discharge section 12.
In addition, the suction member 36 has a slit 38 formed at the tip on the discharge unit 12 side, and a connecting tube 39 is provided on a part of the surface (opposite surface) opposite to the surface on which the slit 38 is formed. It has been.
In the cross section perpendicular to the arrangement direction of the tip openings 16a, one of the side surfaces of the suction member 36, that is, the surface sandwiched between the surface where the slit 38 is formed and the surface where the connecting tube 39 is formed. A handle 40 is provided on this surface, and a handle 41 is provided on the other surface.
Further, as shown in FIG. 8, the suction member 36 has 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 tip opening 16a, and a connection portion with the suction pump 48 is formed in part. It is substantially the same shape except for the point.

Here, as shown in FIG. 7 and FIG.
The suction member 36 is disposed on both the side surface orthogonal to the side surface on which the handles 40 and 41 are formed. The contact surface 82 which is the surface of the abutting member 80 facing the head unit 70 is formed so as to be in the same plane as the surface of the suction member 36 where the slit 38 is formed, and the nozzle plate 14. Is parallel to the discharge surface. That is, the contact surface 82 of the abutting member 80 is a surface parallel to the end surface 79 of the guide member 78. Further, the contact surface 82 of the abutting member 80 extends in a direction orthogonal to the longitudinal direction of the slit 38 of the suction member 36, that is, a direction orthogonal to the arrangement direction of the tip openings 16 a of the head unit 70.

  The tube 45 is connected to the connection pipe 39 and is also connected to the suction pump 48. That is, the tube 45 allows the suction member 36 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, and sucks the air in the suction member 36 through the tube 45 to make the inside of the suction member 36 have a negative pressure.

  The removing means 32 has such a configuration. By sucking the air around the slit 38 from the slit 38 into the suction member 36, ink droplets and dirt adhered to the nozzle plate 14 at a position facing the slit 38. Aspirate (fixed matter, etc.). This point will be described in detail later.

  The ink trap 46 is disposed in a tube 45 between the suction member 36 and the suction pump 48. The ink trap 46 removes foreign matters such as ink and dust that are sucked by the suction pump 48 and mixed in the air passing through the tube 45, and prevents foreign matters from adhering to and mixing in the suction pump 48. .

  The support 42 has a box shape with one surface open, and supports the suction member 36 in a movable manner. More specifically, the support 42 has a shape that covers the surface of the suction member 36 except the surface on which the slits 38 are formed at a predetermined interval, and can slide the handles 40 and 41 of the suction member 36. Support in the state. Further, the support 42 has an opening formed in a portion corresponding to the connection pipe 39.

The suction member moving mechanism 44 is disposed on the outer wall of the support 42 on the side where the handle 40 of the suction member 36 is formed. That is, the suction member moving mechanism 44 is disposed to face the suction member 36 with the support 42 interposed therebetween.
The suction member moving mechanism 44 is connected to the handle 40 of the suction member 36, and the suction member 36 is parallel to the discharge surface of the nozzle plate 14 and perpendicular to the arrangement direction of the tip openings 16a (arrow in FIG. 7). (X direction).
Here, the suction member moving mechanism 44 moves the slit 38 of the suction member 36 away from one end portion of the tip opening 16a with respect to the center of the tip opening 16a in a direction orthogonal to the arrangement direction of the tip openings 16a. The position is moved from the position facing the part to the position facing the part farther from the other end of the tip opening 16a. That is, the vicinity of the tip opening 16a (around the tip opening 16a) is moved so as to pass through the center of the tip opening 16a. In other words, the vicinity of the tip opening 16a is moved a distance longer than the diameter of the tip opening 16a.
The method by which the suction member moving mechanism 44 moves the suction member 36 is not particularly limited, and various methods such as a method using a cam, a method using an air cylinder, and a method using linear drive can be used.

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, and the suction member 36 and the support body 42 are orthogonal to the discharge surface of the nozzle plate 14. In the direction of movement (arrow Y direction in FIG. 7).
That is, the removal mechanism moving unit 34 moves the suction member 36 from a standby position separated from the discharge surface of the nozzle plate 14 by a predetermined distance to a position close to the nozzle plate 14.

The support base 50 is fixed at a predetermined position such as a housing (not shown).
The drive screw 52 is formed of a ball screw (not shown) having a male screw portion that is screwed with a female screw portion (not shown) formed in the coupling body 56, and the direction orthogonal to the discharge surface of the nozzle plate 14. Is supported by the support base 50 so as to be rotatable.
The drive screw 52 is rotated by a drive unit 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. A drive screw 52 is screwed into the coupling body 56 and a guide rail 54 is penetrated.
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 discharge surface of the nozzle plate 14. By moving the coupling body in this manner, the support body 42 and the suction member 36 supported by the support body 42 are also moved in a direction orthogonal to the discharge surface of the nozzle plate 14.
In this way, the removal mechanism moving unit 34 can bring the suction member 36 into and out of contact with the discharge unit 12. That is, the distance between the slit 38 of the suction member 36 and the tip opening 16a of the discharge unit 12 can be adjusted.

  Here, the removal mechanism moving unit 34 moves the suction member 36 in a direction orthogonal to the discharge surface of the nozzle plate 14, and brings the contact surface 82 of the abutting member 80 into contact with the end surface 79 of the guide member 78. In the present embodiment, by appropriately setting the length of the guide member 78 in the direction orthogonal to the discharge surface of the nozzle plate 14, the slit 38 of the suction member 36 faces the discharge surface of the nozzle plate 14, and this discharge It can be brought close to a position that is not in contact with the surface.

  Thus, the removal mechanism moving means 34 moves the suction member 36 so that the suction member 36 is brought close to the head unit 70 when the maintenance device 30 is used, and the suction member 36 is moved to the head unit when not used. More specifically, by separating the suction member 36 from the recording head 136 rather than the transport path of the recording medium P, the maintenance device 30 transports the recording medium P and the recording medium when creating a label. It is possible to prevent the image drawing on 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.

  Further, the suction member moving mechanism 44 moves the suction member 36 in a state where the abutting member 80 is in contact with the guide member 79, that is, in a state where the slit 38 is opposed to and close to the discharge surface of the nozzle plate 14. Let That is, the abutting surface 82 of the abutting member 80 is slidably brought into contact with the end surface 79 of the guide member 78, and the suction member 36 is moved in a direction orthogonal to the arrangement direction of the tip openings 16a. Thereby, the slit 38 of the suction member 36 can be moved in a direction orthogonal to the arrangement direction of the tip openings 16 a and parallel to the discharge surface of the nozzle plate 14 without contacting the suction unit 36. .

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 136K.
The ink pressurization mechanism 64 pressurizes the ink in the supply pipe 61 to discharge the ink from the front end openings 16a of the respective 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 tip opening 16a.
The solenoid valve is not limited to this embodiment. For example, the electromagnetic valve is a three-way valve, and is provided at a connection 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; The state where 136K and the ink tank 60 communicate with each other may be switched.

  As shown in FIG. 9, the maintenance device 30 configured in this manner is arranged to face each of the head units 70 in one of the arrangements of the head units arranged in the arrangement direction of the tip openings 16 a. Is done. For the sake of simplicity, FIG. 9 shows the suction member 36 provided with an abutment member 80 as a main part of the maintenance device 30. Here, the maintenance device 30 has a moving mechanism for moving the head unit 70 from the arrangement of one head unit 70 to the head units 70 of the other arrangement. The moving mechanism is not particularly limited, and a moving mechanism using various methods such as a method using a drive screw, a method using a cam, a method using an air cylinder, and a method using linear drive can be used.

Here, as shown in FIG. 9, the maintenance device 30 is not limited to a configuration in which the maintenance device 30 is arranged in only one of the head unit arrangements, and one maintenance device 30 is provided for each of the head units 70. Therefore, it is not necessary to provide a moving mechanism for moving the maintenance device 30 from one arrangement of the head units 70 to the other arrangement, and the moving mechanism can be simplified.
In addition, one maintenance device 30 may be arranged for one recording head so that the recording head can be moved to a position facing each of the head units 70 of the recording head. 30 need not be provided, the device configuration of the maintenance device 30 can be simplified, and the device cost can be reduced.
When a plurality of maintenance devices 30 are arranged, a set of ink traps 46 and suction pumps 48 may be connected to the plurality of maintenance devices 30.
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, FIG. 10A is a cross-sectional view showing the main part of the recording medium having irregularities on the image surface, and FIG. 10B shows the main part of the recording medium pressed without being smoothed. FIG. 10C is a cross-sectional view showing the main part of the recording medium that has been smoothed by the smoothing part and pressed with a 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 202 of the undercoat part 111, and an undercoat liquid is applied to the surface to form an undercoat layer U.
Here, the application roll 202 is rotated in the direction opposite to the conveyance direction of the recording medium P by the drive unit 204. That is, the drive unit 204 moves the coating roll 202 in a direction in which the moving direction of the surface of the coating roll 202 and the moving direction of the recording medium P are opposite to each other at the contact position between the coating roll 202 and the recording medium P. It is rotating.

The recording medium P on which the undercoat liquid has been 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 216.
The undercoat liquid semi-curing unit 216 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. The semi-curing will be described in detail later.

  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> W, 136 </ b> C, 136 </ b> M, 136 </ b> Y, and 136 </ b> K discharge 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 136W, 136C, 136M, and 136Y, ink droplets are ejected from the recording heads 136W, 136C, 136M, and 136Y toward the recording medium P, and thereafter The ultraviolet rays are irradiated from the ultraviolet irradiation unit 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 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. 10A, the image surface of the recording medium P is three-dimensionally swelled by overlapping the cured inks 184 of a plurality of 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. 10B, when foil pressing is performed on an image surface in which the foil donation range is not smoothed (in other words, 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. 10C, the foil 158 can be thermocompression bonded to a smooth surface with a large 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 unit) 148 for irradiating active energy rays, and the image surface is covered with a transparent active energy ray curable liquid and smoothed, whereby the image surface is greatly uneven. 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.

Next, the semi-curing of the undercoat liquid and the ink liquid will be described.
In the present invention, “semi-cured” means partially cured (partial cured), and the undercoat liquid and / or the ink liquid (that is, the colored liquid) is partially cured, but completely cured. The state that is not cured. In addition, when the undercoat liquid applied on the recording medium (base material) P or the ink liquid discharged onto the undercoat liquid is semi-cured, the degree of curing may be uneven. It is preferable that the ink liquid is cured in the depth direction. Here, in this embodiment, the undercoat liquid to be semi-cured is an undercoat liquid forming an undercoat layer, and the ink liquid to be semi-cured is an ink liquid that lands on an undercoat layer or a recording medium to form an ink layer. It is a drop.

  For example, when a radical polymerizable undercoating liquid or ink liquid is cured in air or air partially substituted with an inert gas, the surface of the undercoating liquid or ink liquid may be used for suppressing radical polymerization of oxygen. There is a tendency for radical polymerization to be inhibited. As a result, the semi-curing becomes non-uniform, the curing proceeds more inside the undercoat liquid or the ink liquid, and the surface curing tends to be delayed.

  In the present invention, a radical photopolymerizable undercoat liquid or ink liquid is used in the presence of radical polymerization-inhibiting oxygen and partially photocured, whereby the degree of cure of the undercoat liquid and / or ink liquid is The inside can be higher than the outside.

In addition, in the case where the cationic polymerizable undercoat liquid or ink liquid is cured in the air having moisture, the curing proceeds more inside the undercoat liquid or ink liquid because of the cationic polymerization inhibiting action of moisture, Surface hardening tends to be delayed.
Even if this cationically polymerizable undercoat liquid or ink liquid is partially photocured using humidity conditions having an inhibitory effect on cationic polymerization, the degree of cure of the undercoat liquid and / or ink liquid is higher than that of the outside. Can be higher.

  In this way, the undercoat liquid or ink liquid is semi-cured, and ink droplets are ejected onto the semi-cured undercoat liquid, or an ink liquid having a different hue is applied to the semi-cured ink liquid. When droplets are ejected, a technical effect favorable to the quality of the obtained printed matter can be obtained. Moreover, the action mechanism can be confirmed by observing the cross section of the printed matter.

Hereinafter, the semi-curing of the undercoat liquid (that is, the undercoat layer formed on the recording medium with the undercoat liquid) will be described in detail. In the following, when about 12 pL of ink liquid (that is, ink droplets) is deposited on the semi-cured undercoat liquid having a thickness of about 5 μm provided on the recording medium P. A high density portion will be described as an example.
FIG. 11 is a schematic cross-sectional view showing an example of a recording medium in which an ink liquid is ejected onto a semi-cured undercoat liquid. FIGS. 12A and 12B are uncured undercoat liquids, respectively. FIG. 12C is a schematic cross-sectional view showing an example of a recording medium on which ink liquid has been deposited, and FIG. 12C is a diagram of the recording medium on which ink liquid has been deposited on an undercoat liquid that has been completely cured. It is a typical sectional view showing an example.

According to the present invention, the undercoat liquid is semi-cured, so that the degree of cure on the recording medium P side becomes higher than the degree of cure of the surface layer. In this case, three features are observed. That is, as shown in FIG. 11, when the ink liquid d is ejected onto the semi-cured undercoat liquid U, (1) a part of the ink liquid d comes out on the surface of the undercoat liquid U. (2) Ink liquid A part of d is immersed in the undercoat liquid U, and (3) the undercoat liquid exists between the lower side of the ink liquid d and the recording medium P.
As described above, when the undercoat liquid and the ink liquid satisfy the above conditions (1), (2), and (3) when the ink liquid is ejected onto the undercoat liquid, the undercoat liquid is in a semi-cured state. It can be said that there is.
By semi-curing the undercoat liquid, that is, by curing the undercoat liquid so as to satisfy the above (1), (2), and (3), droplets of ink liquid that has been ejected at high density (that is, Ink droplets) are connected to each other to form an ink liquid film layer (that is, an ink liquid film or an ink layer), which gives a uniform and high color density.

On the other hand, when the ink liquid is ejected onto the uncured undercoat liquid, all of the ink liquid d enters the undercoat liquid U as shown in FIG. 12A and / or FIG. As shown in B), the undercoat liquid U does not exist below the ink liquid d.
In this case, even when the ink liquid is applied at a high density, the droplets are independent of each other, which causes a decrease in color density.

Further, when the ink liquid is ejected onto the completely hardened undercoat liquid, the ink liquid d does not enter the undercoat liquid U as shown in FIG.
In this case, droplet ejection interference occurs, a uniform ink liquid film layer cannot be formed, and color reproducibility cannot be increased (that is, color reproducibility is reduced).

Here, when droplets of ink liquid are applied at high density, the droplets do not become independent, from the viewpoint of forming a uniform ink liquid film layer, and from the viewpoint of suppressing the occurrence of droplet ejection interference, The amount of the uncured portion of the undercoat liquid (that is, the undercoat layer) per unit area is preferably smaller than the maximum droplet amount of the ink liquid applied per unit area, and more preferably sufficiently small. That is, the weight M _u (also referred to as M (undercoat liquid)) per unit area of the uncured portion of the undercoat liquid layer and the maximum weight m _i (m (ink liquid)) of the ink liquid ejected per unit area. ) Preferably satisfies (m _i / 30) <M _u <m _i , more preferably satisfies (m _i / 20) <M _u <(m _i / 3), and (m _i / 10) <M _u <(m _i / 5) is particularly satisfied. Here, the maximum weight of the ink liquid ejected per unit area is the maximum weight per color.
By setting (m _i / 30) <M _u , the occurrence of droplet ejection interference can be prevented, and the dot size reproducibility can be increased. Further, by setting M _u <m _i , the liquid layer of the ink liquid can be formed uniformly, and the decrease in density can be prevented.

Here, the weight of the uncured portion of the undercoat liquid per unit area is determined by a transfer test. Specifically, after completion of the semi-curing process (for example, after irradiation of active energy rays) and before ink droplet ejection, a penetrating medium such as plain paper is pressed against the semi-cured undercoat liquid. Then, the amount of the undercoat liquid transferred to the permeation medium is measured by weight measurement, and the measured value is defined as the weight of the uncured portion of the undercoat liquid.
For example, the maximum amount of the second ink, in droplet deposition density of 600 × 600 dpi, is set to 12 picoliters per pixel, the maximum weight _{m i} of the ink ejected per unit area, and 0.04 g / cm ² (Note that the density of the ink liquid is about 1.1 g / cm ³ ). Therefore, in this case, the weight _{M u} uncured portions per unit area of the undercoat liquid is preferably to 0.0013 g / cm ² greater than 0.04 g / cm less than ^2, from 0.002 g / cm ² greater more preferably to less than 0.013 g / cm ^2, it is particularly preferable to increase the 0.008 g / cm ² than 0.004 g / cm ^2.

Next, the semi-curing of the ink liquid (that is, the ink droplet landed on the recording medium or the undercoat layer or the ink layer formed by the landed ink droplet) will be described.
FIG. 13 is a schematic cross-sectional view on the semi-cured first ink d _a shown a recording medium where ink droplets have been deposited d _b, FIG. 14 (A) and (B) is in an uncured state, respectively is a schematic sectional view showing an example of a recording medium having ink d _b is deposited as droplets onto the first ink d _a, FIG. 14 (C) hitting the ink on the ink liquid while being fully cured It is a typical sectional view showing an example of a recording medium dropped.
The ink d _a after ejected, when forming a secondary color by ink d _b is deposited as droplets onto the first ink d _a is the ink d _b onto the first ink d _a semi-cured It is preferable to give.
Here, the semi-cured state of the first ink d _a, the same as the semi-cured state of the undercoating liquid described above, as shown in FIG. 13, when the second ink d _b is deposited as droplets onto the first ink d _a , (1) a portion of the second ink _{d b} emerges at the surface of the first ink _{d a,} (2) a portion of the second ink _{d b} lies within the first ink _{d a,} and (3) ink _{d b} the lower is a condition where there is an ink d _a.
By thus semi-curing the ink, can be suitably superimposed cured film of the ink d _a a (colored film A) and an ink liquid d _b cured film (colored film B), good color reproduction Is possible.

In contrast, when ink d _b is deposited as droplets onto the first ink d _a uncured, or all of the ink d _b as shown in FIG. 14 (A) sinks into ink d _a, and / or in a state where there is no ink d _a is the lower layer of the ink d _b as shown in FIG. 14 (B). In this case, even if high density imparts ink d _b droplets, since the droplets are independent of each other, causing the color saturation of the secondary color to decrease.

Also, if ink d _b is deposited _as droplets completely cured ink on d _a, ink d _b as shown in FIG. 14 (C) does not sink into ink d _a. In this case, droplet ejection interference occurs, a uniform ink liquid film layer cannot be formed, and color reproducibility is reduced.

Here, the droplets are not independent of each other when applying droplets of a high density ink d _b, the viewpoint of forming a uniform film of the second ink d _b, and suppress the occurrence of fired droplet interference from the viewpoint of the amount of the uncured portion of the ink d _a per unit area is preferably less than the maximum droplet amount of the ink d _b applied per unit area, and more preferably substantially smaller. That is, _(also referred to as _M (ink liquid A).) Weight M _da per unit surface area of uncured regions of the first ink d _a layer and the maximum weight of the ink ejected per unit area m _{db (m} (ink liquid B )))) Preferably satisfies (m _db / 30) <M _da <m _db, and more preferably satisfies (m _db / 20) <M _da <(m _db / 3). , (M _db / 10) <M _da <(m _db / 5) is particularly preferable.
By setting (m _db / 30) <M _da , the occurrence of droplet ejection interference can be prevented, and the dot size reproducibility can be increased. In _addition, by setting M da _{<m db,} can uniformly form a film of the first ink _{d a,} a decrease in density can be prevented.

Here, the weight of the uncured portion of the ink d _a per unit area, as in the case of the undercoating liquid described above, and requests the transfer test. Specifically, after completion of the semi-curing step (e.g., after irradiation of an active energy ray) before deposition of the droplets of the second ink d _b a, a permeable medium such as plain paper in a semi-cured state ink is pressed against the liquid d _a layer, the amount of _the first ink d _a that transfers to the permeable medium is determined by weight measurement. the measured value is defined as the weight of the uncured regions of the first ink.
For example, the maximum amount of the second ink _{d b,} in droplet deposition density of 600 × 600 dpi, is set to 12 picoliters per pixel, the maximum weight _{m db} of the second ink _{d b} ejected per unit surface area, 0.04 g / cm ² and becomes (assuming the density of the second ink _{d b} is about 1.1g / cm3.). Therefore, in this case, the weight _{M da} uncured portions per unit area of the first ink _{d a} layer is preferably set to 0.0013 g / cm ² greater than 0.04 g / cm less than ^2, 0.002 g / more preferably greater 0.013 g / cm less than ² than cm ^2, and particularly preferably a large 0.008 g / cm less than ² than 0.004 g / cm ^2.

  When the semi-cured state of the undercoat liquid and / or the ink liquid is realized by a polymerization reaction of a polymerizable compound that is initiated by irradiation with active energy rays or heating, a non-polymerization rate (that is, from the viewpoint of improving the scratching property of the printed matter A (after polymerization) / A (before polymerization) is preferably from 0.2 to 0.9, more preferably from 0.3 to 0.9, and from 0.5 to 0.00. Particularly preferably, it is 9 or less.

Here, A (before polymerization) is the absorbance of the infrared absorption peak due to the polymerizable group before the polymerization reaction, and A (after polymerization) is the absorbance of the infrared absorption peak due to the polymerizable group after the polymerization reaction. .
For example, when the polymerizable compound contained in the undercoat liquid and / or the ink liquid 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 peak absorbance. Moreover, when a polymeric compound is an oxetane compound, the absorption peak based on a polymeric group (oxetane ring) can be observed in 986 cm < ^-1 > vicinity, It is preferable to define the said polymerization rate with the absorption luminous intensity of this peak. When the polymerizable compound is an epoxy compound, an absorption peak based on a 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.

  In addition, 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.

  In the case of a curing reaction based on an ethylenically unsaturated compound or a cyclic ether, the unpolymerization rate can be quantitatively measured by the reaction rate of the ethylenically unsaturated group or the cyclic ether group.

  As a method for semi-curing the undercoat liquid and / or the ink liquid, (1) a basic compound is imparted to the acidic polymer, or an acidic compound or a metal compound is imparted to the basic polymer. , A method using a so-called agglomeration phenomenon, (2) The undercoating liquid and / or the ink liquid is prepared to have a high viscosity in advance, and the viscosity is lowered by adding a low boiling organic solvent thereto, and the low boiling organic solvent is evaporated. (3) A method of returning to the original high viscosity by heating and cooling the undercoat liquid and / or ink liquid prepared to a high viscosity, and (4) a method of returning to the original high viscosity. There are known thickening methods such as a method in which an active energy ray or heat is applied to the ink liquid to cause a curing reaction. Among these, (4) a method in which an active energy ray or heat is applied to the undercoat liquid and / or the ink liquid to cause a curing reaction is preferable.

  The method of causing a semi-curing reaction by applying active energy rays or heat is a method in which the polymerization reaction of the polymerizable compound on the surface of the undercoat liquid and / or ink liquid applied to the recording medium is insufficient. is there. On the surface of the undercoat liquid and / or ink liquid, the polymerization reaction tends to be hindered by the influence of oxygen in the air as compared with the inside. Therefore, the semi-curing reaction of the undercoat liquid and / or the ink liquid can be caused by controlling the application conditions of the active energy ray or heat.

The amount of energy required for semi-curing the undercoat liquid and / or ink liquid varies depending on the type and content of the polymerization initiator, but generally 1 to 500 mJ / cm ² when energy is applied by active energy rays. The degree is preferred. In addition, when energy is applied by heating, it is preferable to heat for 0.1 to 1 second under the condition that the surface temperature of the recording medium is in a temperature range of 40 to 80 ° C.

The generation of active species due to decomposition of the polymerization initiator is promoted by applying active energy rays such as actinic light and heating, or heat, and the polymerization property or cross-linking property due to the active species is increased by increasing the active species or increasing the temperature. The curing reaction by polymerization or crosslinking of the material is accelerated.
Moreover, thickening (viscosity increase) can also be suitably performed by irradiation with actinic light or heating.

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.

In addition, an ultraviolet irradiation unit is arranged between the recording heads, and ink droplets that have landed on the recording medium by the recording heads, that is, images are semi-cured so that ink droplets of different colors landed at close positions. Can be prevented, and the landed ink droplets can be prevented from moving. Further, by semi-curing the ink liquid, a uniform ink layer can be formed, interference between ink droplets can be prevented, and a plurality of different ink layers can be suitably stacked.
The ultraviolet irradiation unit irradiates ultraviolet rays for several hundred milliseconds to five seconds after the ink droplets have landed on the recording medium by the recording head, so that the ink droplets that have landed on the recording medium are half cut. It is preferable to cure.
By semi-curing the ink droplets within a few hundred milliseconds to 5 seconds after the ink droplets have landed, the shape of the ink droplets on the recording medium can be prevented from collapsing, and high-quality images can be formed. can do.

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 202 and further rotating the coating roll 202 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 202 is separated from the recording medium P after the coating roll 202 has applied the undercoat liquid to the recording medium P by rotating the coating roll 202 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, the inkjet head according to the fourth aspect of the present invention that removes droplets and dirt adhering to the ejection surfaces of the nozzle plates 14 of the recording heads 136W, 136C, 136M, 136Y, and 136K, particularly around the tip opening 16a. A maintenance method will be described.
The maintenance method for the ink jet head (recording head) is the same for all of the recording heads 136W, 136C, 136M, 136Y, and 136K. Therefore, the case of the recording head 136K will be described as a representative.
FIGS. 15A and 15B 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 removing member 32 such as the support member) is used as shown in FIG. More specifically, it is on standby 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 the maintenance of the head unit 70 of the recording head 136K is performed, the maintenance apparatus 30 first uses the suction member moving mechanism 44 as shown in FIG. The suction member 36 is moved toward the discharge surface of the nozzle plate 14 so that the contact surface 82 of the abutting member 80 contacts the end surface 79 of the guide member 78. In this manner, the suction member 36 is moved to the head unit 70 side of the recording head 136K, and the slit 38 of the suction member 36 is brought close to the front end opening 16a of the ejection unit 12. In other words, the slit 38a is moved to the tip opening 16a side to a position where it does not contact the tip opening 16a.

Next, the maintenance device 30 is in a state where the abutting member 80 is in contact with the guide member 79, that is, in a state where the slit 38 is opposed to and close to the discharge surface of the nozzle plate 14, by the suction pump 48. While sucking air and / or ink around the slit 38 by sucking the air inside the suction member 36 to a negative pressure, that is, in this embodiment, suction is performed while sucking ink together with air from the slit 38. The slit 38 of the suction member 36 is moved by the member moving mechanism 44. Here, the maintenance device 30 slides the contact surface 82 of the abutting member 80 against the end surface 79 of the guide member 78 and moves the suction member 36, thereby being parallel to the discharge surface of the nozzle plate 14, and The slit 38 of the suction member 36 is moved in a direction orthogonal to the arrangement direction of the tip openings 16a.
Specifically, the maintenance device 30 shows the suction member 36 in FIG. 15B while sucking air and / or ink from the slit 38 in a state where the slit 38 is close to the ejection surface of the nozzle plate 14. Move from the position of the solid line to the position of the dotted line. That is, the slit of the suction member 36 passes through both end portions of the tip opening 16a.

In this way, the maintenance device 30 causes the guide member 78 provided on the support frame 72 to abut the abutment surface 82 of the abutting member 80, thereby preventing the head unit 70 from contacting the head unit 70. A slit 38 of the suction member 36 can be disposed at a position facing and close to the discharge surface.
Also, the maintenance device 30 moves the suction member 36 by bringing the contact surface 82 of the abutting member 80 into sliding contact with the end surface 79 of the guide member 78 provided on the support frame 72 so that the suction member 36 moves. Without contacting the head unit 70, the slit 38 of the suction member 36 can be moved in a direction orthogonal to the arrangement direction of the tip openings 16 a and parallel to the ejection surface of the nozzle plate 14.

Thus, the maintenance device 30 can perform maintenance without contacting the head unit 70 disposed on the support frame 72. Thereby, compared with the case where the removal unit 80 is positioned with reference to the head unit 70 as in the prior art, in particular, the removal unit with reference to the head unit 70 attached to the support frame 72 via the alignment adjustment mechanism 74. As compared with the case of positioning the head unit 70, it is possible to prevent the displacement of the arrangement position of the head unit 70. That is, the abutting surface 82 of the abutting member 80 is not contacted with the end surface 79 of the guide member 78 that does not interfere with the alignment adjusting mechanism 74 without using the head unit 70 disposed on the support frame 72 via the alignment adjusting mechanism 74 as a reference. Since the removal unit is positioned by being brought into contact with the end surface 79 of the guide member 78 as a reference, it is possible to prevent the head unit 70 from being displaced.
Further, by preventing the deviation in the arrangement interval between the head units 70, it is possible to prevent the occurrence of streak unevenness (see FIG. 25) due to the deviation in the interval between the tip openings due to the deviation in the arrangement interval between the head units 70. can do. That is, according to the present invention, the arrangement of the head unit 70 can be maintained in a good state, and the drawing performance of the recording head can be maintained in a good state.

Further, the slit 38 in the state of sucking air and / or ink is moved in the vicinity of the discharge surface of the nozzle plate 14 and moved around the tip opening 16a in this way, so that the periphery of the tip opening 16a on the discharge surface of the nozzle plate 14 is moved. Ink droplets and dirt adhering to the ink can be sucked and removed.
By sucking and removing ink droplets and dirt around the tip opening 16a in this way, the ejection direction of the ink droplets ejected from the tip opening 16a can be made constant. That is, it is possible to prevent the ink droplet landing positions from being displaced.
Thereby, a high-quality image can be stably formed on the recording medium.

Also, the slits of the suction member are elongated in the arrangement direction of the tip openings, and the ink droplets and dirt adhered around the plurality of tip openings formed in a line on the nozzle plate by the slit of one suction member Can be sucked and removed simultaneously, and the head unit 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 nozzle plate, that is, in this embodiment, the length of the suction members in the arrangement direction is arranged in a row. By setting the length to cover all the tip openings arranged in the nozzle plate, it is possible to simultaneously maintain all the tip openings formed in a row on the nozzle plate with one suction member. The head unit can be maintained without being moved in the arrangement direction.

  In addition, the ink droplets and solid matter adhering around the tip opening of the nozzle plate ejection surface can be removed without contacting the nozzle plate ejection surface, which can damage the nozzle plate ejection surface. Can be prevented.

In addition, since the distance for moving the slit of the suction member is as short as only one tip opening in a direction perpendicular to the arrangement direction of the tip openings, the drive mechanism can be simplified.
Moreover, the opening diameter of a slit can be made small by attracting | sucking, moving the slit of a suction member. That is, even with a slit having a small opening diameter, the entire area around the tip opening can be scanned to remove ink droplets and dirt around the tip opening.
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, ink droplets and dirt around the tip opening can be sucked more reliably.

  In addition, by moving the slit and changing the position for sucking ink droplets and dirt, the suction force acting on the ink droplets and dirt adhering to the nozzle plate can be changed, and more suction is performed. It can be made easier.

  Thus, according to the present embodiment, ink droplets and dirt around the tip opening 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.

  In the present embodiment, the surface of the suction member where the slit is formed and the contact surface of the abutting member are configured to be on the same plane, and the length of the guide member is determined appropriately, thereby However, the present invention is not limited to this, and the length in the direction perpendicular to the discharge surfaces of the guide member and the abutting member is appropriately set. You may decide.

Here, the suction member moving mechanism preferably reciprocates the suction member (its slit) in a direction parallel to the ejection surface of the nozzle plate 14 and perpendicular to the arrangement direction.
By reciprocating the slit with respect to the tip opening, ink droplets and dirt around the tip opening can be sucked and removed more reliably.
In addition, since the region in which the slit is reciprocated in the direction orthogonal to the arrangement direction is only around one ejection unit, the suction member (slit) can be reciprocated in a short time with a simple apparatus configuration.

Further, when the distance between the tip openings is d [mm] and the size of the suction port in the direction perpendicular to the arrangement direction of the tip openings is L [mm], the suction member moving mechanism moves the suction member in the arrangement direction of the tip openings. It is preferable to move (2 × d + L) [mm] or more in the orthogonal direction. That is, it is preferable that the suction member moving mechanism moves the slit by (2 × d + L) [mm] or more in a direction orthogonal to the arrangement direction of the tip openings.
By setting the moving distance of the suction member as the above condition, ink droplets and dirt around the tip opening of the discharge surface of the nozzle plate can be reliably removed in a shorter time.

The size of the slit (suction port described later) in the direction orthogonal to the arrangement direction of the tip openings is preferably 0.5 mm or more and 2.0 mm or less, and preferably 0.5 mm or more and 1.0 mm or less. More preferred.
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.

Next, another example of the recording head maintenance method will be described. In the present embodiment, the recording head maintenance method is the same for each of the plurality of head units of the recording head, and therefore, one head unit will be described as a representative.
FIGS. 16A to 16E are process diagrams for explaining another example of the maintenance method of the head unit 70 of the recording head.

  At the start of the maintenance, as shown in FIG. 16A, ink droplets or the like are attached around the tip opening 16a of the ejection surface of the nozzle plate 14 of the head unit 70.

  From this state, first, as shown in FIG. 16B, the ink in the supply pipe 61 is pressurized from the ink pressurizing mechanism 64, and ink droplets are discharged from all the tip openings 16 a of the head unit 70. At this time, the valve of the electromagnetic valve 66 is closed to seal the supply pipe 61. This prevents the ink in the supply pipe 61 from flowing back into the ink tank 60 when the ink in the supply pipe 61 is pressurized by the ink pressurization mechanism 64.

  By discharging the ink from all the tip openings 16a of the head unit 70, as shown in FIG. 16C, the ink is attached to the entire ejection surface of the nozzle plate 14, that is, the ink is wet (ink Wetted).

Thereafter, as shown in FIG. 16D, ink droplets and dirt adhering to the ejection surface of the nozzle plate 14 are sucked by the maintenance device 30 in the same manner as described above.
Specifically, the slit is brought close to the tip opening, the slit in a state of sucking air and / or ink is moved, and ink droplets and dirt adhering to the ejection surface of the nozzle plate 14 are sucked.

  By sucking ink droplets and dirt adhering to the ejection surface of the nozzle plate 14 by the maintenance device 30, the ink droplets and dirt adhere to the ejection surface of the nozzle plate 14 as shown in FIG. Not in a state.

As described above, the ink pressurization mechanism discharges ink droplets from the opening at the front end and wets the ejection surface of the nozzle plate 14 with ink, whereby the ink droplets can be easily sucked.
Further, the dirt adhering around the tip opening of the discharge surface of the nozzle plate 14 can be removed together with the discharge of the ink from the tip opening, and the dirt (fixed matter) is easily sucked by wetting with the ink. be able to.

  As described above, according to the present embodiment, ink droplets attached to the ejection surface of the nozzle plate 14 and dirt can be more easily sucked, and ink droplets attached to the ejection surface of the nozzle plate 14 Dirt can be removed more reliably.

Here, when discharging ink from the opening at the tip, it is preferable to arrange a plate-like liquid flow guide 68 at a position facing the ejection surface of the nozzle plate 14 as shown in FIG.
In this way, the liquid flow guide 68 is disposed at a position facing the discharge surface of the nozzle plate 14, and a flow path for the ink discharged from the tip opening is formed between the discharge surface of the nozzle plate 14 and the liquid flow guide. can do.
Thus, by disposing the liquid flow guide 68, the discharge surface of the nozzle plate 14 can be easily wetted with a small amount of ink.
Further, the solid matter adhering to the ejection surface of the nozzle plate 14, that is, the dirt, can be washed away by the liquid flow of the ink flowing through the flow path formed between the ejection surface of the nozzle plate 14 and the liquid flow guide 68. It is possible to reliably remove the dirt adhering to the ejection surface.

  In this embodiment, the ink in the supply pipe 61 is pressurized by the ink pressurizing mechanism 64 to discharge the ink from the tip opening 16a. However, the method of attaching the ink to the ejection surface of the nozzle plate 14 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 part and discharged from each tip opening.

Next, another example of the maintenance device of the present invention will be described.
FIG. 18 is a schematic configuration diagram showing another example of the maintenance apparatus of the present invention.
The maintenance device 31 shown in FIG. 18 has the same configuration as the maintenance device 30 shown in FIG. 7 except that the suction member 36 is provided with a liquid flow guide 69. The same reference numerals are attached, and the description thereof is omitted. Hereinafter, the points peculiar to the maintenance device 31 will be mainly described.

  As shown in FIG. 18, the maintenance device 31 includes a removing unit 32 and a removing mechanism moving mechanism 34. The removing means 32 includes a suction member 36, a support 42, a suction member moving mechanism 44, an ink trap 46, a suction pump 48, and a liquid flow guide 69.

As shown in FIG. 18, the liquid flow guide 69 is formed on the side where the slit 38 of the suction member 36 is formed, that is, on the side facing the discharge surface of the nozzle plate 14 from the longitudinal end of the slit 38. , A plate-like member extending along a direction orthogonal thereto.
The liquid flow guide 69 is provided along one end of the ends in the direction orthogonal to the longitudinal direction of the slit 38, in this embodiment, the end on the side where the handle 40 is provided, and the nozzle plate 14. It protrudes in a direction perpendicular to the longitudinal direction of the slit 38 in the same plane as the surface facing the discharge surface.
The liquid flow guide 69 is formed over the long side of the surface of the suction member 36 on the side where the slit 38 is formed. That is, the liquid flow guide 69 has a length substantially equal to the length of the slit 38 in the longitudinal direction.

  The liquid flow guide 69 is located between the nozzle plate 14 and the nozzle plate 14 at a position close to the tip opening 16a so as to face the nozzle plate 14 (the discharge surface on which the tip opening 16a of the nozzle plate 14 is formed). A gap is formed in This gap is filled with ink, and this gap becomes a flow path of the ink ejected from the tip opening 16a.

  Next, a recording head maintenance method of the present invention using this maintenance device 31 will be described. 19A to 19C are cross-sectional views showing how the maintenance of the recording head is performed by the maintenance device 31. FIG.

  First, while the image is recorded by the recording head, that is, while the label is produced, the suction member 36 (and the removing member 32 such as the support member) is connected to the recording head as shown in FIG. Waiting at a remote position, specifically, waiting at a position (standby position) that does not hinder the conveyance of the recording medium P.

When the label printing apparatus 100 finishes producing the label and performs maintenance of the recording head 136K, the maintenance apparatus 31 uses the removal mechanism moving mechanism 34 to direct the suction member 36 and the liquid flow guide 69 toward the discharge surface of the nozzle plate 14. By moving, the contact surface 82 of the abutting member 80 is brought into contact with the end surface 79 of the guide member 78. That is, the suction member 36 and the liquid flow guide 69 are brought close to the discharge surface of the nozzle plate 14. Further, as shown in FIG. 19B, the suction member moving mechanism 44 moves the suction member 36 in a direction orthogonal to the arrangement direction of the tip openings 16a until the liquid flow guide 69 faces the tip openings 16a.
As described above, the liquid flow guide 69 is close to the position facing the ejection surface of the nozzle plate 14, whereby a gap is formed between the nozzle plate 14 and the liquid flow guide 69.

  In this manner, in a state where the nozzle plate 14 and the liquid flow guide 69 are close to each other, first, the ink in the supply pipe 61 is pressurized using the ink pressurizing mechanism 64 (see FIG. 6). As shown in (B), the ink droplets are discharged from all the tip openings 16a of the recording head 136K. The discharged ink passes through the gap formed by the ejection surface of the nozzle plate 14 and the liquid flow guide 69 and spreads in the direction in which the tip openings 16a are arranged and in the direction perpendicular to the direction of arrangement. That is, the gap formed between the ejection surface of the nozzle plate 14 and the liquid flow guide 69 becomes an ink flow path.

In this way, the ink flow path is formed between the discharge surface of the nozzle plate 14 and the liquid flow guide 70 by making the discharge surface and the liquid flow guide 69 face each other. With this ink flow path, ink can flow along the ejection surface, and the ejection surface including the periphery of the tip opening 16a can be reliably and easily wetted even with a small amount of ink discharged. Further, the solid matter and the like attached to the discharge surface of the nozzle plate 14 can be washed away by the liquid flow of the ink flowing along the discharge surface. It can be removed reliably.
At this time, the valve of the electromagnetic valve 66 is closed to seal the supply pipe 61. This prevents the ink in the supply pipe 61 from flowing back into the ink tank 60 when the ink in the supply pipe 61 is pressurized by the ink pressurization mechanism 64.

When the discharge of ink from the tip opening 16a is stopped, the ink is attached to the entire ejection surface of the nozzle plate. That is, the ejection surface is wet with ink (wet with ink).
The maintenance device 30 sucks air and / or ink around the slit 38 by sucking the air inside the suction member 36 by the suction pump 48 to negative pressure, and using the suction member moving mechanism 44 to suck the air and / or ink around the slit 38. The suction members 36 (slits 38) are moved in a direction parallel to the ejection surface of the nozzle plate 14 and perpendicular to the arrangement direction. Specifically, the suction member 36 is moved from the solid line position shown in FIG. 15B to the dotted line position. That is, the slit of the suction member 36 passes through both end portions of the tip opening 16a.

  Thus, the slit 38 in a state of sucking air and / or ink (in this embodiment, air and ink) is not in contact with the ejection surface of the nozzle plate 14, in other words, the slit 38a is on the tip opening 16a side. By disposing it at a position not in contact with the tip opening 16a and moving around the tip opening 16a, dirt such as ink droplets and fixed matter adhering around the tip opening of the ejection surface of the nozzle plate 14 is sucked, Can be removed.

  In this way, by sucking and removing ink droplets and solid matter around the tip opening 16a, the ejection direction of the ink droplets ejected from the tip opening 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 liquid flow guide 69 is integrally formed with the suction member 36 so as to extend on the side of the suction member 36 where the slit 38 is formed so as to face the surface where the tip opening 16a of the discharge portion 12 is formed. It is not necessary to separately provide a moving mechanism for the liquid flow guide 69, or it is not necessary to provide a separate liquid flow guide including the moving mechanism, and the apparatus configuration can be simplified.

  Here, as shown in FIG. 19B, the amount of ink discharged for the maintenance of the recording head is such that the ink flow path formed by the ejection surface and the liquid flow guide 69 is filled with ink, and the ink is further discharged. By setting the amount to be able to flow out from the ink flow path, it is possible to wash away dirt such as solid matter attached to the discharge surface and the periphery of the tip opening 16a.

Here, a part of the ink flowing out from the ink flow path flows into the suction member 36 from the suction port 38, but a part of the ink is sucked from between the ejection surface and the liquid flow guide 70 (ink flow path). There is a case where the gas flows out to the side of the member 36. Therefore, in this embodiment, when the amount of ink discharged during maintenance flows out from the ink flow path, it is preferable to provide a leakage prevention mechanism that prevents the ink flowing out from the ink flow path from leaking into the apparatus.
As an ink leakage prevention mechanism, an ink receiver configured by disposing a sponge-like resin member or a non-woven fabric absorbing member around the suction member 36 or between the suction member 36 and the support 42. Is exemplified. By providing such an ink leakage prevention mechanism, the ink that has flowed out from the ink flow path to the side surface of the suction member 36 is absorbed to prevent the ink from leaking into the apparatus, thereby causing the ink to leak into the apparatus. , It is possible to prevent the inside of the apparatus from becoming dirty.

In the maintenance device 31, assuming that the opening diameter of the tip opening is R and the suction port size in the direction perpendicular to the arrangement direction of the tip openings is L, the size in the direction perpendicular to the longitudinal direction of the liquid flow guide 69, that is, The size in the direction orthogonal to the slit arrangement direction is preferably (L + R + 2 mm) or more.
By making the width in the direction perpendicular to the longitudinal direction of the liquid flow guide satisfy the above range, the discharge surface can be wetted with a smaller amount of ink. In addition, the ink flow that flows through the ink flow path can surely wash off dirt such as fixed matter adhering to the ejection surface.

  Here, in the present embodiment, the amount of ink discharged during maintenance is not limited to the amount of ink flowing out of the ink flow path as in the illustrated example, and at least the ink fills the ink flow path, and from the ink flow path. It may be an amount that does not flow out. Thereby, the periphery of the tip opening can be wetted with ink with a small amount of ink discharge.

  In the present embodiment, the liquid flow guide 70 is provided along the end on the side where the handle 40 is provided in the end in the direction orthogonal to the longitudinal direction of the slit 38, but the handle 41 is provided. It may be provided along the end on the other side, or may be provided on both sides.

Next, another embodiment of the maintenance device will be described.
FIG. 20 is a cross-sectional view illustrating a schematic configuration of the maintenance device 220.
FIG. 21 is a perspective view showing the recording head 136 </ b> K and the maintenance device 220.
The maintenance device 220 includes a removing unit 222 and a removing mechanism moving unit 224.
The removing unit 222 includes a suction member 226, a suction member moving mechanism 234, an ink trap 46, and a suction pump 48. The maintenance device 220 is composed of the same members as the above-described maintenance device 30 except for the suction member 226, the suction member moving mechanism 234, and the removal mechanism moving means 224 of the removing means 222. Are denoted by the same reference numerals, and the description thereof is omitted.

The suction member 226 includes a suction nozzle 227, a suction port 228, a contact surface 230, and a guide part 232, and is disposed to face the discharge part 12 of the head unit 70.
The contact surface 230 which is the surface on the discharge surface side of the nozzle plate 14 of the suction member 226 is the length of the contact surface 230 in the direction orthogonal to the arrangement direction of the tip openings 16a parallel to the discharge surface of the nozzle plate 14. Is at least larger than the arrangement interval of the pair of guide members 78 sandwiching the head unit 70 facing each other, whereby the suction member 226 can abut against the pair of guide members 78 simultaneously.

  Here, as shown in FIG. 20, the guide part 232 protrudes in the direction orthogonal to the contact surface 230, and extends in the arrangement direction of the tip openings 16a. The guide portion 232 is separated by a distance that allows the pair of guide members 78 sandwiching the head unit 70 to be sandwiched from both sides in the arrangement direction of the tip openings 16 a when the contact surface 230 contacts the guide member 78. And provided parallel to each other.

  The suction nozzle 227 is a tubular member provided inside the suction member 226 in a direction orthogonal to the discharge surface of the nozzle plate 14. The suction nozzle 227 has a suction port 228 that opens on the surface of the suction member 226 on the head unit side. Further, the side of the suction nozzle 227 opposite to the side where the suction port 228 is formed is connected to the suction pump 48 via the tube 45.

The suction member 226 configured as described above causes the contact surface 230 to contact the guide member 78 during maintenance of the recording head. Thereby, the suction port 228 of the suction member 226 can be disposed at a position facing the discharge surface of the nozzle plate 14 and being in non-contact. That is, the suction port 228 of the suction member 226 can be opposed to and close to the ejection surface of the nozzle plate 14.
Here, in the suction port 228, the size of the tip openings 16a in the arrangement direction is preferably larger than (2 × d) [mm] when the distance between the tip openings 16a is d [mm]. The suction port 228 preferably has a size in a direction perpendicular to the arrangement direction of the tip openings 16a of 0.5 mm or more and 2.0 mm or less, and more preferably 0.5 mm or more and 1.0 mm or less. .

  The suction member moving mechanism 234 is a moving mechanism that moves the suction member 226 in the arrangement direction of the tip openings. As the suction member moving mechanism 234, for example, a mechanism similar to the removing mechanism moving means 224 using a drive screw and a guide rail can be used. The suction member moving mechanism 234 is not particularly limited, and various moving mechanisms using a method using a cam, a method using an air cylinder, and a method using linear drive may be used.

  The suction member 226 is moved in the direction in which the tip openings 16a are arranged by the suction member moving mechanism 234 in a state where the suction member 226 is brought close to the discharge surface of the nozzle plate 14. At this time, the contact surface 230 is slidably contacted with the end surface 79 of the guide member 78, so that the suction port 228 is positioned parallel to the discharge surface and in the arrangement direction of the front end openings 16a at a position facing the front end opening 16a. Moved.

The removing mechanism moving unit 224 is a moving mechanism that moves the removing unit 222 in a direction orthogonal to the ejection surface of the nozzle plate 14. That is, the removal mechanism moving unit 224 moves the suction member 226 from a standby position separated from the discharge surface of the nozzle plate by a predetermined distance to a position where the contact surface 230 contacts the end surface 79 of the guide member 78.
The removal mechanism moving unit 224 can use the same mechanism as the above-described removal mechanism moving unit 34, and thus detailed description thereof is omitted.

  As shown in FIG. 21, the thus configured maintenance device 220 is arranged in each array of head units 70 (two rows in this embodiment) arranged in the direction of arrangement of the leading end openings 16a in the recording head 136K. Arranged every time.

  Next, when performing maintenance of the recording head, the maintenance device 220 moves the suction member 226 toward the discharge surface of the nozzle plate 14 by the suction member moving mechanism 224 and moves the contact surface 230 of the suction member 226 to the guide member 78. It is made to contact | abut to the end surface 79 of this. That is, the suction member 226 is brought close to the discharge surface of the nozzle plate 14, and the suction port 228 is brought close to the discharge surface at a position facing the tip opening 16a.

  Next, the maintenance device 220 uses the suction member moving mechanism 234 to suck air and / or ink around the suction port 228 by sucking the air inside the suction nozzle 227 by the suction pump 48 to negative pressure. The contact surface 230 is slidably contacted with the end surface 79, and the suction member 226 and the suction port 228 are moved in parallel with the discharge surface of the nozzle plate 14 and in the arrangement direction of the tip openings 16a. The maintenance device 220 moves the suction port 228 from one end to the other end of the array of the tip openings 16a formed by the corresponding array of head units. That is, the maintenance device 220 moves the suction member 226 so that the suction port 228 passes through a position facing the entire front end opening 16a of the array of head units facing each other. The suction member 226 may be moved in one direction in the arrangement direction of the tip openings, or may be reciprocated in the arrangement direction.

  Thus, the suction port 228 in a state of sucking air and / or ink (in this embodiment, air and ink) is disposed at a position facing the tip opening 16a, parallel to the ejection surface of the nozzle plate 14, and By moving the suction member 226 and the suction port 228 in the arrangement direction of the front end openings 16a, ink droplets and fixed matter attached around the front end opening of the discharge surface of the nozzle plate 14 as in the above-described maintenance device 30. Such as dirt can be sucked and removed. Further, this makes it possible to make the ejection direction of the ink droplets ejected from the tip opening 16a constant. That is, it is possible to prevent the landing positions of the ink droplets from being shifted, and a high-quality image can be stably formed on the recording medium.

Further, the contact surface 230 of the suction member 226 is brought into contact with the end surface 79 of the guide member 78 and is brought into sliding contact, that is, the guide member 78 provided on the support frame 72 is used to support the support frame. By determining the position in the ejection surface direction of the nozzle plate 14 of the maintenance device 220, the maintenance of the recording head can be performed without the suction member 226 coming into contact with the plurality of head units 70 arranged on the support frame, as in the maintenance device 30. It can be performed. Further, since the head unit 70 is not contacted, it is possible to prevent the head unit from being displaced due to maintenance.
Further, by providing the guide portion 236 on the contact surface 230 of the suction member 226, when the contact surface 230 contacts the end surface 79 of the guide member 78, the suction member 226 is orthogonal to the arrangement direction of the tip openings. Can be prevented.

Here, the maintenance device 220 is arranged for each arrangement of the head units. However, the present invention is not limited to this, and a moving mechanism for moving the maintenance device between the head unit arrangements is provided to perform maintenance of the plurality of head unit arrangements. You may make it carry out with one maintenance apparatus. Thus, by using one maintenance device, the device configuration can be simplified and the device can be made inexpensive.
Further, a maintenance device may be provided for each head unit 70, whereby the recording head can be maintained in a short time.
In the maintenance device 220, the contact surface of the suction member is abutted against the guide member, that is, the suction member is abutted against the guide member. However, an abutment member may be provided separately from the suction member.

Here, in the above-described embodiment, before the air and / or ink is sucked from the suction port, that is, when the suction pump 48 is stopped, the suction member of the removal means is orthogonal to the discharge surface of the nozzle plate by the removal mechanism moving means. The slit is arranged in the vicinity of the discharge surface of the nozzle plate by moving in the direction, that is, the distance between the suction port and the discharge surface is set to a certain distance or less. May be moved parallel to the discharge surface of the nozzle plate and parallel to the arrangement direction of the tip openings.
That is, as shown in FIGS. 22 (A) and (B), the standby position of the removing means is spaced from the position facing the discharge surface of the nozzle plate by a predetermined distance in a direction parallel to the arrangement direction of the tip openings, Specifically, it is located outside the width direction of the transport path of the recording medium P, and the removal mechanism moving mechanism positions the removal means from the standby position (solid line in FIG. 22A) to the nozzle plate (head substrate). You may make it move to (FIG. 22 (A) middle dotted line).
Here, although not shown in FIGS. 22A and 22B, the moving mechanism for moving the removing means in a direction parallel to the arrangement direction of the tip openings is not particularly limited. For example, a suction member (removing means) Similarly to the method of moving the nozzle plate in the direction perpendicular to the discharge surface of the nozzle plate, various moving means such as a method using a ball screw, linear drive, and belt conveyance can be used.
In this way, the moving device can also be moved by setting the standby position of the removing means to the outside of the recording medium conveyance path and moving the maintenance device parallel to the ejection surface of the nozzle plate and parallel to the arrangement direction of the tip openings. 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. 22A and 22B, when the standby position of the removing unit is outside the transport path of the recording medium P, the removing unit 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. 22A) to the position (dotted line in FIG. 22A) facing the nozzle plate by the removal mechanism moving mechanism. Subsequent operations are the same as the maintenance method described above.

  Here, at the start of maintenance, the removal mechanism is moved by the removal mechanism moving mechanism from the standby position (solid line in FIG. 22A) to the position facing the nozzle plate (dotted line in FIG. 22A). Although the maintenance is performed by the above-described maintenance method, the present invention is not limited to this. For example, as shown in FIG. 16B, in a state where the removal means is made to wait at the standby position (solid line in FIG. 22A) by the removal mechanism moving mechanism, the ink is discharged from the front end opening and the discharge is stopped. After that, the removal means may be moved from the standby position to a position facing the nozzle plate (dotted line in FIG. 22A), and then maintenance may be performed. As a result, it is possible to prevent ink from being applied to the maintenance device 30 when the ink is discharged.

  In addition, when discharging the ink while the maintenance device is in the standby position, a leakage prevention device that prevents the discharged ink from leaking into the printing device at a position facing the nozzle plate when discharging the ink. The leakage prevention device may be retracted after disposing and stopping discharging, and the maintenance device may be moved to a position facing the nozzle plate. By providing the leakage prevention device, it is possible to prevent the ink from leaking into the label printing apparatus and being contaminated with the ink. The leakage prevention device includes, for example, an ink receiving mechanism in which a member that absorbs ink is disposed on a support having a size corresponding to the entire region where the tip opening of the recording head is formed, and the ink receiving mechanism is moved. And a moving mechanism to be moved.

  In each of the above embodiments, the recording head of the drawing unit is a full-line head type in which the discharge ports (discharge units) are arranged in a row. However, the present invention is not limited to a single row arrangement, as shown in FIG. The recording heads 640 may be arranged in a staggered manner with a plurality of rows of ejection openings (ejection sections) being shifted by a certain pitch. 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. 23, when the ejection portions of the recording head are arranged two-dimensionally, that is, in a matrix arrangement, the suction port of the maintenance device may be provided for each row of the ejection portions of the recording head. A moving mechanism for moving in the direction perpendicular to the arrangement direction of the tip openings (ejection units), that is, in the row direction is provided, and the nozzle plate of the recording head having a plurality of columns of ejection units by moving one suction port in the row direction. Ink droplets and dirt around the tip opening of the ejection surface may be sucked and removed.

  Further, in the above 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. A single maintenance device may be used to maintain a plurality of recording heads, that is, remove ink droplets and dirt adhering around the front end opening of the ejection surface of the nozzle plate. Thus, by using one maintenance device, the device configuration can be simplified and the device can be made inexpensive.

  Further, in this embodiment, one slit corresponding to all the tip openings arranged in a row is formed as the suction port of the suction member, but the present invention is not limited to this, and the slit is divided into a plurality of pieces. It may be provided. For example, a suction port may be provided for each tip opening arranged in a row, and ink droplets and dirt adhering around each discharge portion of the discharge surface of the nozzle plate may be sucked.

Note that, as in the suction members of the maintenance devices 30 and 31 described above, the suction port whose longitudinal direction is the arrangement direction of the tip openings is preferably divided in a direction orthogonal to the arrangement direction of the ejection units. That is, it is preferable to arrange a partition plate parallel to the arrangement direction at the tip opening of the suction member.
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 tip opening can be more reliably removed.

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. 24 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 shown in FIG. 24, a buffer is arranged 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 positions.

  In this embodiment, the active energy curable ink is used as the ink, and the active energy curable ink is ejected from the recording head to form an image of the active energy curable ink on the recording medium P. Although described as a digital label printing apparatus that irradiates light, cures an image, and fixes an image on a recording medium, the present invention is not limited to this, and will be described in detail later with specific examples. An ink jet recording apparatus that fixes an image on the recording medium P by heating and pressurizing the image recorded on the recording medium P can also 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.

  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) ^max ) / 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. γs (saturation) ^max 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) ^max ) / 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. γs (saturation) ^max is the maximum value of γs (saturation) determined 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.

The γs (0), γs (saturated), and γs (saturated) ^max will be specifically described below.
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 (Saturation) ^max 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, γs (saturation) ^max is the maximum value of γs (saturation) ¹ and γs (saturation) ² , and 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) ^max = 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) ^max ) /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 (saturated) ^max } / 4
It is more preferable to satisfy the relationship
γs ≦ γs (saturation) ^max
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)
In the present invention, as the surfactant, 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, A substance having strong surface activity against at least one solvent among methanol, water, isobornyl acrylate, 1,6-hexanediol diacrylate, and polyethylene glycol diacrylate, preferably hexane, toluene, propylene glycol monomethyl ether, For at least one solvent among isobornyl acrylate, 1,6-hexanediol diacrylate, and polyethylene glycol diacrylate More preferably, the substance has a strong surface activity against at least one solvent among propylene glycol monomethyl ether, isobornyl acrylate, 1,6-hexanediol diacrylate, and polyethylene glycol diacrylate. It is preferable to use a substance, particularly preferably a substance having a strong surface activity with respect to at least one solvent among isobonyl acrylate, 1,6-hexanediol diacrylate, and polyethylene glycol diacrylate.

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, the curing sensitivity being double 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 has either a constitution that does not contain a colorant or a content of the colorant that is less than 1% by mass, or a constitution in which the undercoat liquid contains a white pigment as a colorant. It is preferable.
Hereinafter, each component constituting the ink and / or the 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 ′ -Peroxidation of tetrakis (p-isopropylcumylperoxycarbonyl) benzophenone, di-t-butyldiperoxyisophthalate, etc. It is preferable to use an ester type.

  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 combination with adjacent A ³ , A ⁴ and an adjacent carbon atom, 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 reduce 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 a 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, as the undercoat liquid and ink, an active light curable undercoat liquid and ink are used and cured by irradiating the undercoat liquid and ink with actinic rays. 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. 2A is a bottom view illustrating a schematic configuration of a recording head, and is a cross-sectional view taken along line BB of the recording head of FIG. (A) is a side view showing a schematic configuration of the recording head, (B) is a bottom view showing an arrangement pattern of ejection portions of the recording head, and (C) is a recording head of FIG. 5 (A). 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. It is a VII-VII line fragmentary sectional view showing a schematic structure of a maintenance device shown in FIG. It is a schematic perspective view which shows the shape of the attraction | suction member shown in FIG. FIG. 2 is a perspective view illustrating a schematic configuration of a recording head and a maintenance device. 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. FIG. 6 is a schematic cross-sectional view showing an example of a recording medium in which an ink liquid is ejected onto a semi-cured undercoat liquid. (A) and (B) are schematic cross-sectional views showing an example of a recording medium in which an ink liquid is deposited on an uncured undercoat liquid, and (C) is a completely cured state. FIG. 3 is a schematic cross-sectional view showing an example of a recording medium in which an ink liquid is ejected onto an undercoat liquid. FIG. 5 is a schematic cross-sectional view illustrating an example of a recording medium in which an ink liquid is ejected onto a semi-cured ink liquid. (A) and (B) are schematic cross-sectional views showing an example of a recording medium in which an ink liquid is ejected onto an uncured ink liquid, respectively, and (C) is a completely cured state. FIG. 3 is a schematic cross-sectional view illustrating an example of a recording medium on which ink liquid is ejected onto the ink liquid. (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. (A)-(C) is process drawing which shows an example of the maintenance method using the maintenance apparatus shown in FIG. 18, respectively. It is sectional drawing which shows schematic structure of the other example of a maintenance apparatus. FIG. 2 is a perspective view illustrating a schematic configuration of a recording head and a maintenance device. (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. It is explanatory drawing which shows a mode that a stripe unevenness generate | occur | produces when drawing with the recording head which has several head units.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 Discharge part 13 Head substrate 14 Nozzle plate 16 Nozzle 16a Tip opening 18 Pressure chamber 20 Supply port 22 Common flow path 24 Actuator 26 Pressure plate 28 Individual electrode 30 Maintenance device 32 Removal means 34 Removal mechanism moving means 36 Suction member 38 Slit 40, DESCRIPTION OF SYMBOLS 41 Handle 42 Support body 44 Suction member moving mechanism 45 Tube 46 Ink trap 48 Suction pump 50 Support stand 52 Drive screw 54 Guide rail 56 Connection body 60 Ink tank 61 Supply piping 62 Filter 64 Ink pressurization mechanism 66 Solenoid valve 68 Liquid flow guide DESCRIPTION OF SYMBOLS 70 Head unit 72 Support frame 74 Alignment adjustment mechanism 76, 77 Groove part 78 Guide member 79 End surface 80 Abutting member 82 Contact surface 90 Axis 100 Digital label printing apparatus 110 Conveying part 1 DESCRIPTION OF SYMBOLS 1 Undercoat part 112 Drawing part 114 Maintenance part 116 Smoothing part 118 Foil pushing part 120 Label extraction part 121 Control part 122 Supply roll 124,126,128,130,132 Conveying roller pair 134 Product winding part 135 Recording head unit 136C, 136C 136M, 136K recording head (inkjet head)
137 Ink storage / loading unit 138 Ultraviolet irradiation unit 142 Varnish coater 144, 145 Application roll 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 202 Coating roll 204 Drive part 206 Blade 208 Storage part 210 Positioning part 212, 214 Positioning roller 216 Undercoat liquid semi-curing part 220 Maintenance device 222 Removal means 224 Removal mechanism moving means 226 Suction member 227 Suction nozzle 228 Suction port 230 Contact surface 232 Guide portion 234 Suction member moving mechanism

Claims (14)

Each of the plurality of ejection ports for ejecting ink droplets is formed in a row on the ejection port plate, the plurality of head units match the arrangement direction of the ejection ports, and the relative positions between the plurality of inkjet head units are determined. An inkjet head maintenance device arranged on a support frame by an alignment adjustment mechanism for adjusting,
In the direction orthogonal to the arrangement direction, each inkjet head unit of the plurality of inkjet head units is sandwiched and disposed on both sides thereof, and the ejection port of the ejection port plate is formed on the support frame. At least two guide members having end faces parallel to the surface being
A suction member formed with at least one suction port facing the surface of the ejection port plate of each inkjet head unit on which the ejection port is formed, and provided on the suction member and adjusted by the alignment adjusting mechanism. Further, the surface of the discharge port plate is opposed to the surface on which the discharge port is formed in contact with the end surfaces of the guide members on both sides of each of the inkjet head units so that the relative position between the plurality of inkjet head units does not change. And the abutting member which arrange | positions the said suction opening of the said suction member in the position which becomes non-contact, the said abutting member is made to slide-contact with the said end surface of the said guide member of the both sides, and the said suction opening is said discharge outlet A removal unit comprising a moving mechanism for moving the plate in parallel with the surface on which the discharge port is formed, and
An inkjet head maintenance device comprising a suction pump for sucking air in the suction member. The suction port is an opening whose longitudinal direction is the arrangement direction of the discharge ports,
The inkjet head maintenance apparatus according to claim 1, wherein the moving mechanism moves the suction port in a direction orthogonal to an arrangement direction of the discharge ports.   The inkjet head maintenance apparatus according to claim 2, wherein the moving mechanism moves the suction port by a distance longer than at least the size of the ejection port in a direction orthogonal to the arrangement direction of the ejection ports. The suction port is an opening corresponding to at least one region of the discharge port;
The inkjet head maintenance apparatus according to claim 1, wherein the moving mechanism moves the suction member in an arrangement direction of the discharge ports.   The inkjet head maintenance device according to claim 4, wherein the abutting member is formed integrally with the suction member.   The inkjet head maintenance device according to claim 1, further comprising means for discharging ink from the ejection port and wetting the surface of the ejection port plate on which the ejection port is formed with ink.   The means for wetting is further discharged from the inkjet head between a surface of the discharge port plate on which the discharge port is formed and a surface of the discharge port plate on which the discharge port is formed. The inkjet head maintenance apparatus according to claim 6, further comprising a liquid flow guide that forms a flow path of the ink.   The inkjet head maintenance device according to claim 7, wherein the liquid flow guide is disposed along at least one end of the suction port in the moving direction of the suction port of the moving mechanism.   The inkjet head maintenance device according to claim 1, further comprising a removal unit moving unit that moves the removal unit in a direction orthogonal to a surface of the discharge port plate on which the discharge port is formed. . A plurality of discharge ports for discharging ink droplets are arranged corresponding to each of the plurality of discharge ports and a plurality of discharge ports for discharging the ink droplets from the respective discharge ports. A plurality of inkjet head units, and an inkjet head having a support frame that arranges the plurality of inkjet head units with the arrangement direction of the ejection ports aligned, and
An ink-jet head assembly comprising the ink-jet head maintenance device according to claim 1. An inkjet head assembly according to claim 10;
Relative moving means for moving a recording medium for discharging the ink droplets from the plurality of discharge ports of the plurality of ink jet heads of the ink jet head assembly relative to the ink jet head assembly. An inkjet recording apparatus. A plurality of ejection openings for ejecting ink droplets are formed in a row on the ejection orifice plate, the plurality of inkjet head units match the arrangement direction of the ejection openings, and the relative positions between the plurality of inkjet head units A maintenance method for an ink jet head disposed on a support frame by an alignment adjustment mechanism for adjusting
Discharging ink from the discharge port, wetting the surface of the discharge port plate on which the discharge port is formed with the ink,
Between the plurality of head units adjusted by the alignment adjusting mechanism, abutment member provided on a suction member in which at least one suction port facing the surface on which the discharge port is formed of the discharge port plate is formed. The suction port is brought into contact with a guide member provided on the support frame and having an end surface parallel to the surface on which the discharge port is formed so that the relative position of the discharge port plate does not change. Opposite to the surface where the outlet is formed and close to a non-contact position,
A maintenance method for an ink jet head, wherein at least one of air and ink is sucked from the suction port and is moved in parallel to a surface of the discharge port plate on which the discharge port is formed. The suction port is an opening whose longitudinal direction is the arrangement direction of the discharge ports,
The ink jet head maintenance method according to claim 12, wherein the suction port is moved in a direction orthogonal to the arrangement direction of the discharge ports. The suction port is an opening corresponding to at least one region of the discharge port;
The inkjet head maintenance method according to claim 12, wherein the suction member is moved in a direction in which the discharge ports are arranged.

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