JP2007283732A - Digital label printing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital label printing apparatus with high productivity capable of performing foil pressing-printing to various media to be recorded and printing an added value high quality label. <P>SOLUTION: The digital label printing apparatus 100 has an image forming means 20 for forming an image on the medium S to be recorded being a continuous sheet, and a foil pressing means 40 for providing a foil 45 on the medium S to be recorded after recording. On the upstream of the foil pressing means 40, a smoothing means 30 for smoothing the ink under an imaged state at least within a foil pressing range on the medium S to be recorded by a plane pressing member 31. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a digital label printing apparatus, and more particularly to a digital label printing apparatus capable of high-quality foil stamp printing.

  Conventionally, labels have been produced by flexographic printing, offset printing, letterpress printing, etc. In recent years, digital label printing machines using electrophotographic technology or inkjet technology have been sold due to demands for smaller lots and reduced waste paper. Yes. Among them, the ink jet recording apparatus is attracting attention because of its advantages that high-speed and high-quality recording is possible and running cost is low. In particular, when an active energy curable ink (for example, an ultraviolet curable ink) that is cured by irradiation with active energy (for example, ultraviolet light) is used as the ink, in addition to environmental suitability, it has excellent high-speed fixing properties and is used for label printing. Some labeling systems have been proposed because of the advantage that they can be drawn on various recording media.

  On the other hand, the active energy curable ink cured on the recording medium has a thickness of about 10 microns per color, and the unevenness of the foil in foil press printing, which is one of the important post-printing processes for label printing. There was a problem that the degree of adhesion to the recording medium was insufficient and the foil pressing was not successful. This problem is particularly important because multi-color printing is performed and the unevenness is further increased when multi-color inks overlap.

  Disclosed is an image recording apparatus that eliminates surface irregularities by jetting transparent UV curable ink on the top layer as a means to eliminate irregularities in images recorded on a recording medium using an active energy curable ink. (For example, refer to Patent Document 1).

Japanese Patent Laid-Open No. 2005-74878

  However, the image recording apparatus described in Patent Document 1 improves the poor glossiness of an image caused by non-uniform ink amount by applying and smoothing a transparent ultraviolet curable ink on the image surface. Therefore, the flatness at the level required by foil stamping is not always sufficient. In addition, after transparent UV curable ink is jet-coated, it takes a lot of time for the liquid transparent ink to level naturally and erase the unevenness on the surface, and the effect is not sufficient, such as reduced productivity. It was.

  Furthermore, radical curable inks are the mainstream of UV curable inks from the viewpoint of cost and the like, but radical inks cause polymerization inhibition due to oxygen in the atmosphere, so that strong light intensity is required to cure them. There is a problem that the light source cost becomes very high, and as a result, the apparatus price becomes very high.

  The present invention has been made in view of the above circumstances, and its purpose is high productivity, printing on foils can be performed on various recording media, and high-value labels with added value can be printed. It is to provide a digital label printing apparatus.

The above object of the present invention is achieved by the following digital label printing apparatus.
(1) In a digital label printing apparatus having an image forming unit that forms an image on a recording medium of a continuous sheet based on a digital image signal, and a foil pressing unit that provides a foil to the recording medium after recording.
A digital label printing apparatus comprising a smoothing means for smoothing at least a foil donation range of image state ink on the recording medium upstream of the foil pressing means by a flat pressure member.

  According to the digital label printing apparatus having the above-described configuration, the smoothing means for smoothing at least the foil state image state ink on the recording medium by the flat pressure member is provided upstream of the foil pressing means. The foil can be provided and stamped in the range. As a result, it is possible to improve the degree of adhesion between the recording medium and the foil and perform good foil stamp printing. Further, since the smoothing is performed by the flat pressure member, the smoothing can be performed in a short time without waiting for the leveling of the liquid ink, and the productivity can be improved.

(2) The transparent liquid supply means for supplying the active energy curable transparent ink to the image surface on the recording medium, and the active energy for irradiating the active energy curable transparent ink after the supply with the active energy. The digital label printing apparatus according to (1), further comprising an irradiation unit.

  According to the digital label printing apparatus having the above-described configuration, the smoothing means is active on the transparent liquid supply means for supplying the active energy curable transparent ink to the image surface on the recording medium and the active energy curable transparent ink after the supply. Active energy irradiating means for irradiating energy, so that even if the image surface has large irregularities, the surface of the image surface is covered with an active energy curable transparent ink and smoothed, and the smoothing means A good foil donation range can be formed.

(3) The digital label printing apparatus according to (2), wherein the transparent liquid supply means is a varnish coater.

  According to the digital label printing apparatus having the above configuration, since the transparent liquid supply means is a varnish coater, the transparent liquid is stably applied to the image surface of the recording medium on which the uneven image is formed by a simple and inexpensive mechanism. be able to.

(4) The digital label printing apparatus according to (2), wherein the transparent liquid supply unit is an inkjet.

  According to the digital label printing apparatus having the above configuration, since the transparent liquid supply means is an inkjet, an appropriate amount of the transparent liquid is formed on the image surface of the recording medium on which the uneven image is formed while finely controlling the supply amount of the transparent liquid. Can be supplied.

(5) From the above (2), the planar pressure member has a transparent portion, and transmits the active energy of the active energy irradiation means disposed above the transparent portion to cure the active energy curable transparent ink. (4) The digital label printing apparatus according to any one of (4).

  According to the digital label printing apparatus having the above configuration, the flat pressure member has a transparent portion, and the active energy curable transparent ink is cured by transmitting the active energy of the active energy irradiation means disposed above the transparent portion. Therefore, with the surface of the applied active energy curable transparent ink in contact with the flat pressure member, the active energy is irradiated through the transparent portion of the flat pressure member to cure the active energy curable transparent ink. Can be made.

  As a result, the active energy curable transparent ink can be cured in a state where the contact between the air and the active energy curable transparent ink is cut off. Therefore, the active energy curable transparent ink is a radical active energy curable transparent that causes polymerization inhibition by atmospheric oxygen. Even with ink, polymerization inhibition can be suppressed, and an inexpensive active energy irradiation means with low light intensity can be used. In addition, the curing operation of the active energy curable transparent ink and the smoothing operation by the flat pressure member can be performed at the same time, and the productivity can be improved.

  According to the present invention, it is possible to provide a digital label printing apparatus that has high productivity, can be stamp-printed on various recording media, and can print high-value labels with added value.

  Hereinafter, embodiments of a digital label printing apparatus according to the present invention will be described in detail with reference to the drawings.

(First embodiment)
1 is a schematic configuration diagram of a digital label printing apparatus according to a first embodiment of the present invention, FIG. 2 is a perspective view of image forming means and smoothing means in FIG. 1, and FIG. 3 is a longitudinal sectional view of a recording medium for label printing. 4A and 4B show the foil-pressed state, where FIG. 4A is a cross-sectional view of the main part of the recording medium having irregularities on the image surface, and FIG. 4B is a cross-sectional view of the main part of the recording medium pressed without smoothing. c) is a cross-sectional view of the main part of a recording medium that has been smoothed by a smoothing means and pressed with foil.

  In the following embodiments, an ultraviolet curable inkjet head digital label printing apparatus using an ultraviolet curable ink that is an active energy curable ink will be described as an example of the digital label printing apparatus. The digital label printing apparatus is a label printing apparatus capable of foil stamp printing provided with foil stamping means. Here, foil press printing is a method of pressing a foil such as a gold foil, a silver foil, or a color foil on a book cover or spine cover against a mating member with a heated or unheated letterpress (foil press). It is also called a hot stamp or cold stamp.

  As shown in FIGS. 1 and 2, an ultraviolet curable ink jet head digital label printing apparatus (hereinafter referred to as a digital label printing apparatus) 100 is a continuous sheet label printing recording medium S (hereinafter also referred to as a recording medium S). The image forming area 80, the smoothing area 81, the transport buffer area 82, the foil pressing area 83, and the label removal area 84 are provided in the order of the transport direction.

  In common with each of the areas 80, 81, 82, 83, 84, a conveying unit 10 that conveys the recording medium S of continuous sheets is disposed. In the image forming area 80, an image forming unit 20 that forms an image by discharging and curing ultraviolet curable ink on the recording medium S is disposed.

  In the smoothing area 81, smoothing means 30 for smoothing at least the image state ink in the foil donation range on the recording medium S is disposed.

  The foil pressing area 83 is provided with foil pressing means 40 for supplying a foil to the recording medium S after recording and heat-pressing the recording medium S. The label removing area 84 has a transparent active energy curable ink (hereinafter, transparent). A varnish coater 50 for improving gloss by applying the ink to the image surface, an ultraviolet irradiation unit 56 for irradiating the transparent ink with ultraviolet rays and curing, and a continuous sheet recording medium S with a label-shaped cut. A die cutter 60 to be inserted, a waste removing part 70 that is an unnecessary part peeling part, and a product winding part 19 that takes up a label L that is a product are disposed.

  The image forming unit 20 includes inkjet heads 21Y, 21M, 21C, and 21B that discharge ultraviolet curable ink onto the recording medium S, and an ultraviolet irradiation unit 22 as an active energy irradiation light source.

  The smoothing means 30 is a varnish coater 33 which is a transparent liquid supply means for supplying an active energy curable transparent ink (hereinafter also referred to as a transparent liquid) to the surface of the recording medium S, and the transparent liquid is irradiated with active energy to be cured. It has the ultraviolet irradiation part 32 which is an active energy irradiation means, and the plane pressurization member 31 which presses and smoothes the foil donation range of the recording medium S.

  As shown in FIG. 3, the recording medium S for label printing of continuous sheets has a two-sheet structure in which an adhesive sheet 1 having an adhesive 1a applied on the back surface is superposed on a release paper 2 as a mount. Then, after the image is printed on the surface of the pressure-sensitive adhesive sheet 1 by the image forming unit 20, it is peeled off from the release paper 2 and used.

  The conveyance unit 10 includes a plurality of conveyance roller pairs 11, 12, 13, 14, and 15 that are rotationally driven by a conveyance motor 18 (not shown), and is recorded on a label for printing a continuous sheet wound in a roll shape. The medium S is fed out from the supply roll 16 and is sequentially conveyed to the image forming area 80, the smoothing area 81, the conveyance buffer area 82, the foil pressing area 83, and the label removal area 84.

  Conveyance roller pair 11, 12, 13, 14, 15, in particular, conveying roller pair 13, 14, 15 supply roll 16 disposed in foil pressing area 83 and label removing area 84 and product take-up roll 19 described later. The motor is connected to a transport motor control unit (not shown) to control the rotation speed, and the transport speed of the recording medium S is controlled. For example, the recording medium S in the image forming area 80 and the smoothing area 81 is conveyed at a continuous constant speed. On the other hand, the recording medium S in the foil stamping area 83 and the label removal area 84 is intermittently conveyed in conjunction with the movement of the die cutter 60.

  The transport buffer area 82 provided between the smoothing area 81 and the foil stamping area 83 is designed to reduce the slack of the recording medium S for label printing of continuous sheets caused by the difference in transport speed between the smoothing area 81 and the foil stamping area 83. It is designed to absorb.

  As shown in FIG. 2, the image forming unit 20 disposed in the image forming area 80 includes ink jet heads (ink jet head units) 21Y, 21M, 21C, and 21B that eject ink of each color, and the tip of the ink ejecting unit. Are arranged toward the recording medium S to be conveyed. The inkjet heads 21Y, 21M, 21C, and 21B are full-line type heads having an array of the lengths in the width direction of the recording medium S, and employ piezo-type heads. A head drive control unit (not shown) is connected to the inkjet heads 21Y, 21M, 21C, and 21B, and the ejection amount of each ink color is controlled.

  In addition, ultraviolet irradiation units 22 that irradiate ultraviolet rays are respectively arranged on the downstream side of the respective ink jet heads 21Y, 21M, 21C, and 21B, and have strong energy that can be cured immediately after the ink is placed on the recording medium S. Give and cure. The arrangement of the ultraviolet irradiation unit 22 is configured to irradiate only the ink on the recording medium S, and does not irradiate the ink discharge ports of the inkjet heads 21Y, 21M, 21C, and 21B. Prevent ink curing at the outlet. 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 22.

  The varnish coater 33 of the smoothing means 30 disposed in the smoothing area 81 (downstream of the image forming unit 20) is an active energy curable type on the surface of a pair of coating rollers 34 and 35 that rotate while sandwiching the recording medium S. A transparent ink (transparent liquid) is attached and supplied and applied to the surface (image surface) of the recording medium S on which the image is formed by the image forming unit 20.

  The transparent liquid applied by the varnish coater 33 is an active energy curable transparent ink that can be cured by ultraviolet irradiation, and contains at least a polymerizable compound and a photoinitiator as main components. For example, a cationic polymerization composition, radical polymerization System compositions, aqueous compositions, and the like. Details will be described later.

  The flat pressure member 31 disposed on the downstream side of the varnish coater 33 has a smooth surface 31a facing the recording medium S, moves in the vertical direction (the arrow direction in the figure), and is at least covered. The surface (image surface) in the foil donation range of the recording medium S is pressed by the smooth surface 31a, and the image state ink is smoothed. The smooth surface 31a has an area at least larger than the foil donation range.

  The applied and smoothed transparent liquid is irradiated with active energy (ultraviolet rays) and cured by the ultraviolet irradiation unit 32 disposed on the downstream side of the flat pressure member 31. As the ultraviolet irradiation unit 32, for example, a metal halide lamp, a high pressure mercury lamp, a UV-LED, or the like can be used.

  The varnish coater 33 and the ultraviolet irradiation unit 32 for applying and curing the transparent liquid are not essential devices for smoothing the foil donation range of the recording medium S, but smoothing is better when the transparent liquid is applied to some extent. It is desirable to install it because it provides a surface.

  Further, the foil pressing means 40 arranged downstream is wound around a pair of rollers 43, 44 in which a tape-like foil 45 supplied from a foil supply roll 41 is arranged in parallel with the surface of the recording medium S to be conveyed. After being rolled up, the books are wound around the foil winding roll 42. That is, the tape-shaped foil 45 is disposed between the pair of rollers 43 and 44 so as to be parallel to and almost in contact with the surface of the recording medium S.

  Above the tape-like foil 45 arranged in parallel with the recording medium S, a hot stamp plate (letter plate) 46 made of zinc or brass is disposed. The hot stamp plate 46 includes a relief plate portion 46a formed in a shape to be pressed with a foil on the lower surface thereof, and is configured to be heated in a direction approaching or separating from the recording medium S while being heated by a heating device (not shown). ing. By lowering the hot stamp plate 46 and pressing the relief plate portion 46a against the recording medium S through the foil 45, the foil 45 is heat-pressed on the recording medium S according to the shape formed on the relief plate portion 46a. .

  On the downstream side of the foil pressing means 40, the varnish coater 50 for applying the active energy curable transparent ink to the recording medium S and the active energy curable transparent ink are applied to the recording medium S in order to impart gloss to the image surface and improve the image quality. An ultraviolet irradiation unit 56 is disposed as an active energy irradiation light source for irradiating and curing ultraviolet rays.

  The die cutter 60 is provided with a cut 1b having a desired label shape only in the adhesive sheet 1 of the recording medium S for label printing of a continuous sheet printed (see FIG. 3). The cylinder cutter 61 and the recording medium And a receiving roller 62 disposed on the opposite side of the cylinder cutter 61 with respect to S. In the cylinder cutter 61, a plurality of cutting blades 61a formed in a label shape are wound around the cylindrical surface of the cylinder 61b.

  The die cutter 60 oscillates and rotates intermittently at a speed synchronized with the conveyance speed of the recording medium S while the recording medium S is sandwiched between the cylinder cutter 61 and the receiving roller 62, so that the cutting blade 61a is recorded. Only the adhesive sheet 1 of the medium S is provided with a label-shaped cut 1b.

  Here, the reason why the die cutter 60 swings and rotates intermittently is to solve the problem caused by the mismatch between the circumferential length of the cylindrical surface of the cylinder 61b and the required length of the cutting blade 61a. That is, when the die cutter 60 is continuously rotated to make the label-shaped cut 1b, the recording medium S corresponding to the portion where the cutting blade 61a of the cylinder cutter 61 does not exist is also fed and the recording medium S is wasted. However. By turning and rotating the die cutter 60, the cut 1b can be formed continuously, and the recording medium S can be eliminated.

  The scrap removing part 70 peels off an unnecessary part (peripheral part of the label L) of the pressure-sensitive adhesive sheet 1 that does not become the label (product) L from the release paper 2 and discards it. The label L, which is a product, is wound on the product take-up unit 19 together with the release paper 2 in a state of being attached to the release paper 2 to be a product.

  Next, the operation of the ultraviolet curable inkjet head digital label printing apparatus 100 will be described. As shown in FIG. 1, a continuous sheet label recording medium S fed from a supply roll 16 wound in a roll shape is driven by a plurality of conveying roller pairs 11 and 12 driven by a supply roll 16 and a product roll 19. It is conveyed to the image forming area 80.

  The inkjet heads 21Y, 21M, 21C, and 21B are controlled by a head drive control unit (not shown) and receive UV curable ink from the ink discharge unit at a timing that matches the transport speed of the recording medium S. Discharge toward S. The ink adhering to the recording medium S is immediately irradiated with ultraviolet rays from the ultraviolet irradiation unit 22 to be cured and printed.

  As shown in FIG. 4 (a), the image surface of the recording medium S is three-dimensionally raised by overlapping the cured inks 3 of a plurality of colors. The rising height of the ink varies depending on the ink absorption of the recording medium S (the lower the absorption, the higher the height), but it is about 10 μm per color, and multi-colored ink such as a color portion is used. In some cases, the thickness may be approximately 40 μm. The image surface of the recording medium S is uneven. This unevenness greatly affects the adhesion between the foil 45 and the recording medium S (more specifically, the ink 3 on the recording medium S) when the foil is pressed onto the image surface of the recording medium S.

  Accordingly, the recording medium S on which the image is recorded is conveyed to the smoothing area 81, and first, the transparent liquid 4 having a thickness of about 5 to 30 μm (dry film thickness) is covered by the varnish coater 33 so as to cover the entire raised ink 3. Is applied (see FIG. 4A).

  The recording medium S to which the transparent liquid 4 is applied is pressed by the smooth surface 31a of the flat pressure member 31 that moves downward toward the recording medium S, and as shown by a broken line in FIG. The state ink is crushed and smoothed. The smooth surface 31a of the flat pressure member 31 has an area at least larger than the foil supply range.

  The recording medium S in which the surface of the foil supply range is smoothed in this way is further transported to the foil pressing area 83 via the transport buffer area 82, and the hot stamp plate 46 is transferred to the recording medium via the foil 45. By pressing against S, the foil 45 is heat-pressed onto the recording medium S in accordance with the shape formed on the hot stamp plate 46 (the relief plate portion 46a).

  At this time, as shown in FIG. 4 (b), foil pressing is performed on the image surface in which the foil donation range is not smoothed (in other words, the ultraviolet ray curable ink is discharged and cured in the image forming unit 20). Then, the foil 45 is heated and pressure-bonded only to the convex and concave portions, and is not crimped to the concave portions. That is, the degree of adhesion between the foil 45 and the recording medium S is low and is easily peeled off.

  However, as shown in FIG. 4C, when foil pressing is performed on the recording medium S in which the foil donation range is smoothed in advance by the flat pressure member 31, the foil 45 is thermocompression bonded to a smooth surface having a large area. Therefore, it is possible to perform foil pressing that has a high degree of adhesion between the recording medium S and the foil 45 and is difficult to peel off.

  The recording medium S on which the foil 45 has been pressed is conveyed to a label removal area 84, applied with an active energy curable transparent ink by a varnish coater 50, and further irradiated with ultraviolet rays from an ultraviolet irradiation unit 56 to be activated energy curable transparent. Cure the ink. The formation of the UV curable transparent ink film by the varnish coater 50 and the UV irradiation unit 56 is not always necessary because it is intended to give a glossy image to the image surface to obtain a high-quality image. This step is skipped.

  The die cutter 60 is provided with a cut 1b having a desired label shape only in the adhesive sheet 1 of the recording medium S for label printing of a continuous sheet printed (see FIG. 3), and includes a cylinder cutter 61 and a receiving roller 62. Thus, the cut 1b is made in the shape of the label L only in the pressure-sensitive adhesive sheet 1.

  At this time, as described above, since the die cutter 60 makes the cut 1b having the shape of the label L while swinging intermittently, the cut 1b can be continuously formed, and the recording medium S is wasted. The part never occurs.

  Unnecessary portions other than the label L of the pressure-sensitive adhesive sheet 1 are peeled off from the release paper 2 and taken up by the residue removing portion 70. On the other hand, the label L is wound on the product winder roll 19 together with the release paper 2 in a state of being stuck on the release paper 2 to become a product.

  According to the digital label printing apparatus 100 of the present embodiment, smoothing is performed by the flat pressure member 31 to smooth the image state ink 3 and the transparent liquid 4 in at least the foil donation range on the recording medium S upstream of the foil pressing unit 40. Since the means 30 is provided, the foil 45 can be provided and pressed into the range smoothed by the smoothing means 30. Thereby, the adhesiveness of the recording medium S and the foil 45 can be improved, and favorable foil press printing can be performed. Moreover, since it is smoothed by the flat pressure member 31, it can be smoothed in a short time, and productivity can be improved.

  Further, the smoothing means 30 applies the transparent liquid supply means (varnish coater) 33 for supplying the active energy curable transparent ink to the image surface on the recording medium S and the active energy curable transparent ink (transparent liquid) after the supply. Active energy irradiating means 32 for irradiating active energy, so that even if the image surface has large irregularities, the surface of the image surface is covered with the active energy curable transparent ink and smoothed, and the smoothing means 30 A foil donating range with good flatness can be formed.

  Further, since the transparent liquid supply means 33 is a varnish coater, the transparent liquid 4 can be stably applied to the surface of the recording medium S on which the uneven image is formed by a simple and inexpensive mechanism.

  The transport buffer area 82 may be arranged between the image forming unit 20 and the smoothing unit 30 as in the digital label printing apparatus 101 shown in FIG. The relationship of the arrangement position of the transfer buffer area 82 is the same in the following embodiments.

(Second Embodiment)
Next, a digital label printing apparatus according to the second embodiment will be described with reference to FIG. FIG. 6 is a schematic configuration diagram of a digital label printing apparatus according to the second embodiment of the present invention.

  The smoothing means 30 of the digital label printing apparatus 200 of the present embodiment does not include the varnish coater 33 and the ultraviolet irradiation unit 32 shown in the digital label printing apparatus 100 (see FIG. 1) of the first embodiment, and smoothes. In this embodiment, the means 30 is composed only of the flat pressure member 31.

  Accordingly, the image surface formed by the image forming unit 20 is pressed and smoothed by the flat pressure member 31 as it is (without applying the transparent liquid). Since the other parts are the same as those of the digital label printing apparatus 100 of the first embodiment, the same parts are denoted by the same reference numerals or equivalent signs, and the description is diverted.

  According to the digital label printing apparatus 200 of the present embodiment, the smoothing means 30 for smoothing the image state ink 3 and the transparent liquid 4 on the recording medium S by the flat pressure member 31 is provided upstream of the foil pressing means 40. The foil 45 can be pressed onto the image surface smoothed by the flat pressure member 31. Thereby, the adhesiveness of the recording medium S and the foil 45 can be improved, and favorable foil press printing can be performed.

  Since other configurations and operations are the same as those of the digital label printing apparatus 100 of the first embodiment, the description will be diverted.

(Third embodiment)
Next, a digital label printing apparatus according to a third embodiment will be described with reference to FIG. FIG. 7 is a schematic configuration diagram of a digital label printing apparatus according to a third embodiment of the present invention.

  In the digital label printing apparatus 300 according to the present embodiment, the smoothing unit 330 is a transparent liquid supply unit that supplies active energy curable transparent ink (transparent liquid) to the surface of the recording medium S, and a recording medium. It has a flat pressure member 31 that presses and smoothes the foil supply range of S, and an ultraviolet irradiation unit 32 that is an active energy irradiation means that irradiates and cures the transparent liquid with active energy.

  On the recording medium S on which an image is formed by the image forming unit 20, the transparent liquid 4 is ejected from the inkjet nozzle 333, and the unevenness of the image surface formed by curing the ultraviolet curable ink is covered (FIG. 4 ( a)).

  The recording medium S to which the transparent liquid 4 is applied is pressed by the smooth surface 31a of the flat pressure member 31 that moves downward toward the recording medium S, and as shown by a broken line in FIG. The state ink is crushed and smoothed. The smooth surface 31a of the flat pressure member 31 has an area at least larger than the foil supply range.

  The ultraviolet irradiation unit 32 disposed on the downstream side of the flat pressure member 31 irradiates the transparent liquid 4 applied by the inkjet nozzle 333 with active energy (ultraviolet rays) and cures it. As the ultraviolet irradiation unit 32, for example, a metal halide lamp, a high pressure mercury lamp, a UV-LED, or the like can be used.

  The inkjet nozzle 333 and the ultraviolet irradiation unit 32 for applying and curing the transparent liquid 4 are not essential devices for smoothing the foil donation range of the recording medium S, but somewhat transparent liquid 4 is applied. However, it is desirable to install it because a good smooth surface can be obtained.

  According to the digital label printing apparatus 300 of the present embodiment, since the transparent liquid supply means is the inkjet nozzle 333, the optimum amount is applied to the image surface of the uneven recording medium S while finely controlling the supply amount of the transparent liquid 4. The clear liquid 4 can be supplied.

  Since other configurations and operations are the same as those of the digital label printing apparatus 100 of the first embodiment, the description will be diverted.

(Fourth embodiment)
Next, a digital label printing apparatus according to a fourth embodiment will be described with reference to FIG. FIG. 8 is a schematic configuration diagram of a digital label printing apparatus according to the fourth embodiment of the present invention.

  The smoothing means 430 of the digital label printing apparatus 400 of the present embodiment irradiates the transparent liquid 4 with active energy, and the varnish coater 33 that supplies transparent active energy curable transparent ink (transparent liquid) 4 to the surface of the recording medium S. And a flat pressure member 431 for pressing and smoothing the foil supply range of the recording medium S.

  The flat pressure member 431 has a transparent portion 431b capable of transmitting ultraviolet light in the vicinity of the center thereof, and the lower surface thereof is a smooth surface 431a. The ultraviolet irradiation part 32 is disposed above the transparent part 431b, and the ultraviolet light from the ultraviolet irradiation part 32 passes through the transparent part 431b and is applied to the transparent liquid 4 applied by the varnish coater 33.

  According to the digital label printing apparatus 400, the transparent liquid 4 is applied by the varnish coater 33 to the recording medium S on which an image having unevenness is formed by the image forming unit 20. Then, the recording medium S is pressed by the smooth surface 431a of the flat pressure member 431 that moves downward, and the ultraviolet light of the ultraviolet irradiation unit 32 passes through the transparent part 431b and is irradiated to the transparent liquid 4, and the transparent liquid 4 is cured.

  At this time, the transparent liquid 4 is sandwiched between the recording medium S and the smooth surface 431a of the flat pressure member 431 and hardens while being blocked from oxygen in the air, so that the transparent liquid 4 is absorbed by oxygen in the atmosphere. Even radical inks that easily cause polymerization inhibition can inhibit polymerization inhibition and use a light source with low light intensity.

  According to the digital label printing apparatus 400 of this embodiment, the flat pressure member 431 has a transparent portion 431b, and the active energy irradiation means 32 disposed above the transparent portion 431b receives the transparent portion 431b. Since the active energy curable transparent ink (transparent liquid) 4 is cured by passing through, the surface of the active energy curable transparent ink 4 can be cured while being in contact with the flat pressure member 431.

  As a result, the active energy curable transparent ink 4 can be cured in a state where contact between the air and the air is cut off. Therefore, the active energy curable transparent ink 4 is a radical active energy curable that causes polymerization inhibition due to oxygen in the atmosphere. Even with the type transparent ink 4, polymerization inhibition can be suppressed, and the inexpensive active energy irradiation means 32 with low light intensity can be used. Further, the curing operation of the active energy curable transparent ink 4 and the smoothing operation by the flat pressure member 431 can be performed at the same time, and the productivity can be improved.

  Since other configurations and operations are the same as those of the digital label printing apparatus 100 of the first embodiment, the description will be diverted.

(Fifth embodiment)
Next, a digital label printing apparatus according to a fifth embodiment will be described with reference to FIG. FIG. 9 is a schematic configuration diagram of a digital label printing apparatus according to the fifth embodiment.

  The digital label printing apparatus 500 of the fifth embodiment includes an image forming area 80 and a smoothing area 81, a foil stamping area 83, and a label removal area 84 of the digital label printing apparatus 200 of the second embodiment already described in FIG. These are configured as independent individual devices.

  As shown in FIG. 9, the digital label printing apparatus 500 includes a pre-processing device 501 including an image forming area 80 and a smoothing area 81, and a post-processing device 502 including a foil stamping area 83 and a label removal area 84. .

  The detailed configuration of the image forming area 80, the smoothing area 81, the foil stamping area 83, and the label removal area 84 is the same as that of the digital label printing apparatus 200 of the second embodiment already described with reference to FIG. Are denoted by the same reference numerals or equivalent signs, and the description is diverted.

  The recording medium S is first ejected by the pre-processing device 501 from the ink ejection portions of the inkjet heads 21Y, 21M, 21C, and 21B of the image forming unit 20, and the ultraviolet curable ink is irradiated with ultraviolet rays. It is cured and printed by the ultraviolet rays irradiated from the portion 22. Next, the recording medium S is pressed by the smooth surface 31a of the planar pressure member 31 that moves downward, and the image state ink is crushed to smooth the foil donation range.

  The recording medium S on which the image is formed and the foil supply range is smoothed is supplied to the post-processing device 502, and the hot stamp plate 46 is pressed by the foil pressing means 40 through the foil 45. Thereby, the foil 45 is heat-pressed on the recording medium S in accordance with the shape formed on the hot stamp plate 46 (the relief plate portion 46a). At this time, since the foil supply range is smoothed in advance by the flat pressure member 31, the foil 45 is heat-pressed to a smooth surface having a large area. As a result, the recording medium S and the foil 45 are heat-bonded with a high degree of adhesion, and thus are difficult to peel off.

  The foil-pressed recording medium S is transported to the label removal area 84, applied with an active energy curable transparent ink by the varnish coater 50, and further irradiated with ultraviolet rays from the ultraviolet irradiation unit 56 to cure the ultraviolet curable transparent ink. .

  Then, the cut 1b is made in the shape of the label L only in the pressure-sensitive adhesive sheet 1 by the die cutter 60 (see FIG. 3). On the other hand, the label L is wound on the product take-up unit 19 together with the release paper 2 in a state of being stuck on the release paper 2 to become a product.

  According to the digital label printing apparatus 500 of the present embodiment, the pre-processing apparatus 501 and the post-processing apparatus 502 are configured as separate and independent apparatuses, so that the label L printing and image surface smoothing pre-processing are performed. The process and post-processing processes such as foil stamping, transparent ink application (glossy surface formation), scoring, and scrap removal can be performed as separate operations, and post-processing of various types of labels L can be performed collectively. .

  In general, the time required for printing is often slower than the time required for post-processing such as scrap removal, and one post-processing device 502 can handle a plurality of pre-processing devices 501. Efficient processing is possible.

  Since other configurations and operations are the same as those of the digital label printing apparatus 200 of the second embodiment, the description will be diverted.

  In addition, this invention is not limited to each embodiment and modification which were mentioned above, A deformation | transformation, improvement, etc. are possible suitably.

  In the present invention, the digital label printing apparatus has been described as an ultraviolet curable inkjet head label printing machine. However, the present invention is not limited to this, and can be applied to any type of printing apparatus capable of foil stamp printing. Have the same effect.

  Here, the “active energy” referred to in the present invention is not particularly limited as long as it can impart energy capable of generating a starting species in the ink composition by the irradiation, and broadly includes α rays, Including gamma rays, X-rays, ultraviolet rays, visible rays, electron beams, and the like. Among these, from the viewpoints of curing sensitivity and device availability, ultraviolet rays and electron beams are preferable, and ultraviolet rays are particularly preferable. Therefore, the ink composition of the present invention is preferably an ink composition that can be cured by irradiation with ultraviolet rays.

In the inkjet recording apparatus of the present invention, the peak wavelength of the active energy depends on the absorption characteristics of the sensitizing dye in the ink composition, but is, for example, 200 to 600 nm, preferably 300 to 450 nm, and more preferably 350 to It is suitable that it is 450 nm. In addition, the (a) electron transfer type initiation system of the ink composition of the present invention has sufficient sensitivity even with low output active energy. Therefore, the output of active energy is, for example, 2,000 mJ / cm ² or less, preferably 10 to 2,000 mJ / cm ² , more preferably 20 to 1,000 mJ / cm ² , and still more preferably 50 to 800 mJ. An irradiation energy of / cm ² is appropriate. The active energy exposure surface illuminance (the maximum illuminance of the surface of the recording medium) is, for example, 10 to 2,000 mW / cm ^2, preferably, suitably be irradiated at 20 to 1,000 mW / cm ² is there.
In particular, in the ink jet recording apparatus of the present invention, irradiation with active energy generates ultraviolet rays having an emission wavelength peak of 390 to 420 nm and a maximum illuminance of 10 to 1,000 mW / cm ^{2 on the} surface of the recording medium. The light emitting diode is preferably irradiated.

In the ink jet recording apparatus of the present invention, it is appropriate that the active energy is applied to the ink composition ejected on the recording medium, for example, 0.01 to 120 seconds, preferably 0.1 to 90 seconds. It is.
Furthermore, in the ink jet recording apparatus of the present invention, the ink composition is heated to a constant temperature, and the time from the landing of the ink composition on the recording medium to the irradiation of the active energy is 0.01 to 0.5 seconds. Preferably, it is 0.02 to 0.3 seconds, and more preferably 0.03 to 0.15 seconds. Thus, by controlling the time from the landing of the ink composition to the recording medium to the irradiation of the active energy to an extremely short time, it is possible to prevent the landed ink composition from bleeding before curing. .

  In order to obtain a color image using the ink jet recording apparatus of the present invention, it is preferable to superimpose in order from the color with the lowest brightness. By overlapping in this way, the active energy can easily reach the lower ink, and good curing sensitivity, reduction of residual monomers, reduction of odor, and improvement of adhesion can be expected. In addition, although irradiation with active energy can be performed by injecting all the colors and exposing them together, exposure for each color is preferable from the viewpoint of promoting curing.

  Further, as described above, since the active energy curable ink such as the ink composition of the present invention desirably has a constant temperature for the discharged ink composition, from the ink supply tank to the inkjet head portion, It is preferable to perform temperature control by heat insulation and heating. Moreover, it is preferable that the head unit to be heated is thermally shielded or insulated so that the apparatus main body is not affected by the temperature from the outside air. In order to shorten the printer start-up time required for heating or to reduce the loss of heat energy, it is preferable to insulate from other parts and reduce the heat capacity of the entire heating unit.

  Further, mercury lamps and gas / solid lasers are mainly used as active energy sources, and mercury lamps and metal halide lamps are widely known as ultraviolet light curable ink jets. Furthermore, replacement with a GaN-based semiconductor ultraviolet light emitting device is very useful industrially and environmentally. Furthermore, LED (UV-LED) and LD (UV-LD) are small, have a long lifetime, high efficiency, and low cost, and are expected as radiation sources for active energy curable ink jets.

  Further, as described above, a light emitting diode (LED) and a laser diode (LD) can be used as the active energy source. In particular, when an ultraviolet light source is required, an ultraviolet LED and an ultraviolet LD can be used. For example, Nichia Corporation has introduced a purple LED whose main emission spectrum has a wavelength between 365 nm and 420 nm. Further, when shorter wavelengths are required, US Pat. No. 6,084,250 discloses an LED that can emit active energy centered between 300 nm and 370 nm. Other ultraviolet LEDs are also available and can emit radiation in different ultraviolet bands. A particularly preferable active energy source in the present invention is a UV-LED, and a UV-LED having a peak wavelength of 350 to 420 nm is particularly preferable.

[Recording medium]
The recording medium to which the ink composition of the present invention can be applied is not particularly limited, and various kinds of non-absorbing resin materials used for ordinary non-coated paper, coated paper, so-called soft packaging, or the like. A resin film formed into a film can be used, and examples of the various plastic films include PET film, OPS film, OPP film, ONy film, PVC film, PE film, and TAC film. In addition, examples of the plastic that can be used as the recording medium material include polycarbonate, acrylic resin, ABS, polyacetal, PVA, and rubbers. Metals and glasses can also be used as the recording medium.
In the ink composition of the present invention, when a material with low thermal shrinkage at the time of curing is selected, the adhesive property between the cured ink composition and the recording medium is excellent. Films that tend to curl and deform, such as heat-shrinkable PET film, OPS film, OPP film, ONy film, PVC film, etc., have the advantage that a high-definition image can be formed.

Below, each component used for the ink composition which can be used by this invention is demonstrated sequentially.
[Ink composition]
The ink composition used in the present invention is an ink composition that can be cured by irradiation with active energy, and examples thereof include a cationic polymerization ink composition, a radical polymerization ink composition, and a water-based ink composition. These compositions will be described in detail below.

(Cationically-polymerized ink composition)
The cationic polymerization-type ink composition contains (a) a cationic polymerizable compound, (b) a compound that generates an acid upon irradiation with active energy, and (c) a colorant. If desired, it may further contain an ultraviolet absorber, a sensitizer, an antioxidant, an antifading agent, a conductive salt, a solvent, a polymer compound, a surfactant and the like.
Hereafter, each component used for a cationic polymerization type ink composition is demonstrated one by one.

[(A) Cationic polymerizable compound]
The (a) cationic polymerizable compound used in the present invention is not particularly limited as long as it is a compound that causes a polymerization reaction by an acid generated from a compound that generates an acid by irradiation of active energy (b) described later and cures. Various known cationic polymerizable monomers known as photo cationic polymerizable monomers can be used. Examples of the cationic polymerizable monomer include JP-A-6-9714, JP-A-2001-31892, JP-A-2001-40068, JP-A-2001-55507, JP-A-2001-310938, JP-A-2001-310937, and JP-A-2001-220526. Examples thereof include epoxy compounds, vinyl ether compounds, oxetane compounds and the like.

Examples of the epoxy compound include aromatic epoxides, alicyclic epoxides, and aliphatic epoxides.
Aromatic epoxides include di- or polyglycidyl ethers produced by the reaction of polyphenols having at least one aromatic nucleus or their alkylene oxide adducts and epichlorohydrin, such as bisphenol A or its alkylene oxides. Examples thereof include di- or polyglycidyl ethers of adducts, di- or polyglycidyl ethers of hydrogenated bisphenol A or alkylene oxide adducts thereof, and novolak type epoxy resins. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.

  As the alicyclic epoxide, cyclohexene oxide obtained by epoxidizing a compound having at least one cycloalkane ring such as cyclohexene or cyclopentene ring with a suitable oxidizing agent such as hydrogen peroxide or peracid. Or a cyclopentene oxide containing compound is mentioned preferably.

  Examples of the aliphatic epoxide include dihydric polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof. Typical examples include diglycidyl ether of ethylene glycol, diglycidyl ether of propylene glycol or diglycidyl ether of alkylene glycol such as diglycidyl ether of 1,6-hexanediol, di- or tri- or di- or tri-glycol or adducts thereof. Polyglycidyl ether of polyhydric alcohol such as glycidyl ether, diglycidyl ether of polyethylene glycol or alkylene oxide adduct thereof, diglycidyl ether of polyalkylene glycol represented by diglycidyl ether of polypropylene glycol or alkylene oxide adduct thereof, etc. Can be mentioned. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.

The epoxy compound may be monofunctional or polyfunctional.
Examples of monofunctional epoxy compounds that can be used in the present invention include, for example, phenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, 1,2-butylene oxide, 1,3-butadiene monooxide, 1,2-epoxydodecane, epichlorohydrin, 1,2-epoxydecane, styrene oxide, cyclohexene oxide, 3-methacryloyloxymethylcyclohexene oxide, 3-acryloyloxymethylcyclohexene oxide, 3 -Vinylcyclohexene oxide etc. are mentioned.

  Examples of polyfunctional epoxy compounds include, for example, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, and brominated bisphenol. S diglycidyl ether, epoxy novolac resin, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxy 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-meta-dioxane, bis (3,4-epoxycyclo) Xylmethyl) adipate, vinylcyclohexene oxide, 4-vinylepoxycyclohexane, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3 ′, 4′-epoxy-6 '-Methylcyclohexanecarboxylate, methylenebis (3,4-epoxycyclohexane), dicyclopentadiene diepoxide, ethylene glycol di (3,4-epoxycyclohexylmethyl) ether, ethylenebis (3,4-epoxycyclohexanecarboxylate) , Epoxyhexahydrophthalate dioctyl, epoxyhexahydrophthalate di-2-ethylhexyl, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether Glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ethers, 1,1,3-tetradecadiene dioxide, limonene dioxide, 1,2,7,8- Examples include diepoxyoctane and 1,2,5,6-diepoxycyclooctane.

  Among these epoxy compounds, aromatic epoxides and alicyclic epoxides are preferable from the viewpoint of excellent curing speed, and alicyclic epoxides are particularly preferable.

  Examples of the vinyl ether compound include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, cyclohexanedimethanol divinyl ether, Di- or trivinyl ether compounds such as methylolpropane trivinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexane dimethanol monovinyl ether, n-propyl Pills vinyl ether, isopropyl vinyl ether, isopropenyl ether -O- propylene carbonate, dodecyl vinyl ether, diethylene glycol monovinyl ether, and octadecyl vinyl ether.

The vinyl ether compound may be monofunctional or polyfunctional.
Specifically, examples of monofunctional vinyl ethers include, for example, 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 , Methoxypolyethyleneglycol 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, Examples thereof include 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, and bisphenol F. Divinyl ethers such as alkylene oxide divinyl ether; trimethylolethane trivinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol Hexavinyl 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 addition Examples thereof include polyfunctional vinyl ethers such as pentaerythritol tetravinyl ether, ethylene oxide-added dipentaerythritol hexavinyl ether, and propylene oxide-added dipentaerythritol hexavinyl ether.

  As the vinyl ether compound, a di- or trivinyl ether compound is preferable from the viewpoints of curability, adhesion to a recording medium, surface hardness of the formed image, and the like, and a divinyl ether compound is particularly preferable.

The oxetane compound in the present invention refers to a compound having an oxetane ring, and a known oxetane compound can be arbitrarily selected and used as described in JP-A Nos. 2001-220526, 2001-310937, and 2003-341217. .
The compound having an oxetane ring that can be used in the ink composition of the present invention is preferably a compound having 1 to 4 oxetane rings in the structure. By using such a compound, it becomes easy to maintain the viscosity of the ink composition within a good handling range, and obtain high adhesion between the cured ink composition and the recording medium. Can do.

The compound having such an oxetane ring is described in detail in the above-mentioned JP-A No. 2003-341217, paragraph numbers [0021] to [0084], and the compounds described therein can be suitably used in the present invention.
Among the oxetane compounds used in the present invention, it is preferable to use a compound having one oxetane ring from the viewpoint of the viscosity and tackiness of the ink composition.

In the ink composition of the present invention, these cationic polymerizable compounds may be used alone or in combination of two or more, but from the viewpoint of effectively suppressing shrinkage during ink curing. Is preferably a combination of at least one compound selected from an oxetane compound and an epoxy compound and a vinyl ether compound.
The content of the (a) cationic polymerizable compound in the ink composition is suitably 10 to 95% by mass, preferably 30 to 90% by mass, and more preferably 50 to 85%, based on the total solid content of the composition. It is the range of mass%.

[(B) Compound that generates acid upon irradiation with active energy]
The ink composition of the present invention contains a compound that generates an acid upon irradiation with active energy (hereinafter, appropriately referred to as “photoacid generator”).
Examples of the photoacid generator that can be used in the present invention include photoinitiators for photocationic polymerization, photoinitiators for photoradical polymerization, photodecolorants for dyes, photochromic agents, and light used for microresists. (400-200 nm ultraviolet rays, far ultraviolet rays, particularly preferably g-line, h-line, i-line, KrF excimer laser beam), ArF excimer laser beam, electron beam, X-ray, molecular beam, ion beam, etc. A compound capable of generating can be appropriately selected and used.

  Examples of such a photoacid generator include an onium salt such as a diazonium salt, an ammonium salt, a phosphonium salt, an iodonium salt, a sulfonium salt, a selenonium salt, and an arsonium salt, which decomposes upon irradiation with active energy to generate an acid. Organic halogen compounds, organic metal / organic halides, photoacid generators having an o-nitrobenzyl-type protecting group, compounds that generate sulfonic acids by photolysis, such as iminosulfonates, disulfone compounds, diazoketo A sulfone and a diazo disulfone compound can be mentioned.

  As the photoacid generator, oxazole derivatives and s-triazine derivatives described in JP-A No. 2002-122994, paragraphs [0029] to [0030] are also preferably used. Furthermore, onium salt compounds and sulfonate compounds exemplified in JP-A No. 2002-122994, paragraph numbers [0037] to [0063] can also be suitably used as the photoacid generator in the present invention.

(B) A photo-acid generator can be used individually by 1 type or in combination of 2 or more types.
The content of the (b) photoacid generator in the ink composition is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, and still more preferably in terms of the total solid content of the ink composition. Is 1-7 mass%.

[(C) Colorant]
The ink composition of the present invention can form a visible image by adding a colorant. For example, when forming an image area of a lithographic printing plate, it is not always necessary to add it, but it is also preferable to use a colorant from the viewpoint of plate inspection of the obtained lithographic printing plate.
There is no restriction | limiting in particular in the coloring agent which can be used here, According to a use, well-known various color materials and (pigment, dye) can be selected suitably, and can be used. For example, when forming an image excellent in weather resistance, a pigment is preferable. As the dye, both water-soluble dyes and oil-soluble dyes can be used, but oil-soluble dyes are preferred.

[Pigment]
The pigment preferably used in the present invention will be described.
The pigment is not particularly limited, and all commercially available organic and inorganic pigments or pigments dispersed in an insoluble resin or the like as a dispersion medium, or the resin is grafted onto the pigment surface Can be used. Moreover, what dye | stained the resin particle with dye can be used.
Examples of these pigments include, for example, “Pigment Dictionary” (2000), edited by Seijiro Ito. Herbst, K.M. Hunger “Industrial Organic Pigments”, JP 2002-12607 A, JP 2002-188025 A, JP 2003-26978 A, and JP 2003-342503 A3.

  Specific examples of organic pigments and inorganic pigments that can be used in the present invention include C.I. I. Pigment Yellow 1 (Fast Yellow G etc.), C.I. I. A monoazo pigment such as C.I. Pigment Yellow 74; I. Pigment Yellow 12 (disaji yellow AAA, etc.), C.I. I. Disazo pigments such as C.I. Pigment Yellow 17; I. Non-benzidine type azo pigments such as CI Pigment Yellow 180; I. Azo lake pigments such as C.I. Pigment Yellow 100 (eg Tartrazine Yellow Lake); I. Condensed azo pigments such as CI Pigment Yellow 95 (Condensed Azo Yellow GR, etc.); I. Acidic dye lake pigments such as C.I. Pigment Yellow 115 (quinoline yellow lake, etc.); I. Basic dye lake pigments such as CI Pigment Yellow 18 (Thioflavin Lake, etc.), anthraquinone pigments such as Flavantron Yellow (Y-24), isoindolinone pigments such as Isoindolinone Yellow 3RLT (Y-110), and quinophthalone yellow Quinophthalone pigments such as (Y-138), isoindoline pigments such as isoindoline yellow (Y-139), C.I. I. Nitroso pigments such as C.I. Pigment Yellow 153 (nickel nitroso yellow, etc.); I. And metal complex salt azomethine pigments such as CI Pigment Yellow 117 (copper azomethine yellow, etc.).

  C. As a thing which exhibits red or magenta color, C.I. I. Monoazo pigments such as CI Pigment Red 3 (Toluidine Red, etc.); I. Disazo pigments such as C.I. Pigment Red 38 (Pyrazolone Red B, etc.); I. Pigment Red 53: 1 (Lake Red C, etc.) and C.I. I. Azo lake pigments such as C.I. Pigment Red 57: 1 (Brilliant Carmine 6B); I. Condensed azo pigments such as C.I. Pigment Red 144 (condensed azo red BR, etc.); I. Acidic dye lake pigments such as C.I. Pigment Red 174 (Phloxine B Lake, etc.); I. Basic dye lake pigments such as C.I. Pigment Red 81 (Rhodamine 6G ′ Lake, etc.); I. Anthraquinone pigments such as C.I. Pigment Red 177 (eg, dianthraquinonyl red); I. Thioindigo pigments such as C.I. Pigment Red 88 (Thioindigo Bordeaux, etc.); I. Perinone pigments such as C.I. Pigment Red 194 (perinone red, etc.); I. Perylene pigments such as C.I. Pigment Red 149 (perylene scarlet, etc.); I. Pigment violet 19 (unsubstituted quinacridone), C.I. I. Quinacridone pigments such as CI Pigment Red 122 (quinacridone magenta, etc.); I. Isoindolinone pigments such as CI Pigment Red 180 (isoindolinone red 2BLT, etc.); I. And alizarin lake pigments such as CI Pigment Red 83 (Mada Lake, etc.).

  As a pigment exhibiting blue or cyan, C.I. I. Disazo pigments such as C.I. Pigment Blue 25 (Dianisidine Blue, etc.); I. Phthalocyanine pigments such as C.I. Pigment Blue 15 (phthalocyanine blue, etc.); I. Acidic dye lake pigments such as C.I. Pigment Blue 24 (Peacock Blue Lake, etc.); I. Basic dye lake pigments such as C.I. Pigment Blue 1 (Viclotia Pure Blue BO Lake, etc.); I. Anthraquinone pigments such as C.I. Pigment Blue 60 (Indantron Blue, etc.); I. And alkali blue pigments such as CI Pigment Blue 18 (Alkali Blue V-5: 1).

As a pigment exhibiting green, C.I. I. Pigment green 7 (phthalocyanine green), C.I. I. Phthalocyanine pigments such as C.I. Pigment Green 36 (phthalocyanine green); I. And azo metal complex pigments such as CI Pigment Green 8 (Nitroso Green).
As a pigment exhibiting an orange color, C.I. I. An isoindoline pigment such as C.I. Pigment Orange 66 (isoindoline orange); I. And anthraquinone pigments such as CI Pigment Orange 51 (dichloropyrantron orange).

Examples of the black pigment include carbon black, titanium black, and aniline black.
Specific examples of the white pigment include basic lead carbonate (2PbCO ₃ Pb (OH) ₂ , so-called silver white), zinc oxide (ZnO, so-called zinc white), titanium oxide (TiO ₂ , so-called titanium white), Strontium titanate (SrTiO ₃ , so-called titanium strontium white) or the like can be used.

  Here, titanium oxide has a smaller specific gravity than other white pigments, a large refractive index, and is chemically and physically stable, so that it has a large hiding power and coloring power as a pigment. Excellent durability against other environments. Therefore, it is preferable to use titanium oxide as the white pigment. Of course, other white pigments (may be other than the listed white pigments) may be used as necessary.

For dispersing the pigment, for example, a dispersion device such as a ball mill, a sand mill, an attritor, a roll mill, a jet mill, a homogenizer, a paint shaker, a kneader, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, or a wet jet mill is used. be able to.
It is also possible to add a dispersant when dispersing the pigment. Examples of the dispersant include a hydroxyl group-containing carboxylic acid ester, a salt of a long-chain polyaminoamide and a high molecular weight acid ester, a salt of a high molecular weight polycarboxylic acid, a high molecular weight unsaturated acid ester, a high molecular copolymer, a modified polyacrylate, an aliphatic Examples thereof include polyvalent carboxylic acids, naphthalene sulfonic acid formalin condensates, polyoxyethylene alkyl phosphate esters, and pigment derivatives. It is also preferable to use a commercially available polymer dispersant such as the Solsperse series from Zeneca.
Moreover, it is also possible to use a synergist according to various pigments as a dispersion aid. These dispersants and dispersion aids are preferably added in an amount of 1 to 50 parts by mass with respect to 100 parts by mass of the pigment.

  In the ink composition, as a dispersion medium for various components such as pigments, a solvent may be added, or the solvent-free low molecular weight component (a) cationic polymerizable compound may be used as a dispersion medium. However, the ink composition of the present invention is an active energy curable ink, and is preferably solventless in order to cure the ink after it is applied to a recording medium. This is because if the solvent remains in the cured ink image, the solvent resistance is deteriorated or a VOC (Volatile Organic Compound) problem of the remaining solvent occurs. From such a viewpoint, as the dispersion medium, (a) a cationically polymerizable compound is used, and among them, it is preferable to select a cationically polymerizable monomer having the lowest viscosity in terms of dispersion suitability and handling properties of the ink composition. .

The average particle size of the pigment is preferably 0.02 to 4 μm, more preferably 0.02 to 2 μm, and more preferably 0.02 to 1.0 μm.
Selection of pigments, dispersants, and dispersion media, dispersion conditions, and filtration conditions are set so that the average particle diameter of the pigment particles falls within the above preferred range. By controlling the particle size, clogging of the head nozzle can be suppressed, and ink storage stability, ink transparency, and curing sensitivity can be maintained.

〔dye〕
The dye used in the present invention is preferably oil-soluble. Specifically, it means that the solubility in water at 25 ° C. (the mass of the dye dissolved in 100 g of water) is 1 g or less, preferably 0.5 g or less, more preferably 0.1 g or less. Accordingly, so-called water-insoluble oil-soluble dyes are preferably used.

The dye used in the present invention preferably has an oil-solubilizing group introduced into the above-described dye mother core in order to dissolve the necessary amount in the ink composition.
As the oil-solubilizing group, long chain, branched alkyl group, long chain, branched alkoxy group, long chain, branched alkylthio group, long chain, branched alkylsulfonyl group, long chain, branched acyloxy group, long chain, branched alkoxycarbonyl group, Long chain, branched acyl group, long chain, branched acylamino group long chain, branched alkylsulfonylamino group, long chain, branched alkylaminosulfonyl group and these long chains, aryl groups containing branched substituents, aryloxy groups, aryloxycarbonyl Group, arylcarbonyloxy group, arylaminocarbonyl group, arylaminosulfonyl group, arylsulfonylamino group and the like.
In addition, for water-soluble dyes having carboxylic acid and sulfonic acid, long chain, branched alcohol, amine, phenol, aniline derivatives are used as oil-solubilizing alkoxycarbonyl groups, aryloxycarbonyl groups, alkylaminosulfonyl groups, A dye may be obtained by conversion to an arylaminosulfonyl group.

The oil-soluble dye preferably has a melting point of 200 ° C. or lower, more preferably has a melting point of 150 ° C. or lower, and still more preferably has a melting point of 100 ° C. or lower. By using an oil-soluble dye having a low melting point, the precipitation of dye crystals in the ink composition is suppressed, and the storage stability of the ink composition is improved.
Further, it is desirable that the oxidation potential is noble (high) in order to improve fading, particularly resistance to oxidizing substances such as ozone and curing characteristics. For this reason, as the oil-soluble dye used in the present invention, those having an oxidation potential of 1.0 V (vs SCE) or more are preferably used. The oxidation potential is preferably higher, the oxidation potential is more preferably 1.1 V (vs SCE) or more, and particularly preferably 1.15 V (vs SCE) or more.

As the yellow dye, a compound having a structure represented by the general formula (Y-I) described in JP-A No. 2004-250483 is preferable.
Particularly preferred dyes are dyes represented by the general formulas (Y-II) to (Y-IV) described in paragraph [0034] of JP-A No. 2004-250483. And the compounds described in paragraphs [0060] to [0071] of JP-A-250483. The oil-soluble dye of the general formula (Y-I) described in the publication may be used not only for yellow but also for inks of any color such as black ink and red ink.

The magenta dye is preferably a compound having a structure represented by the general formulas (3) and (4) described in JP-A No. 2002-114930. Specific examples include paragraphs of JP-A No. 2002-114930. Examples include the compounds described in [0054] to [0073].
Particularly preferred dyes are azo dyes represented by the general formulas (M-1) to (M-2) described in paragraph numbers [0084] to [0122] of JP-A No. 2002-121414, and specific examples Examples thereof include compounds described in paragraph numbers [0123] to [0132] of JP-A No. 2002-121414. The oil-soluble dyes represented by the general formulas (3), (4) and (M-1) to (M-2) described in the publication are used not only for magenta but also for any color ink such as black ink and red ink. May be.

Examples of cyan dyes include dyes represented by formulas (I) to (IV) described in JP-A No. 2001-181547, and paragraphs [0063] to [0078] of JP-A No. 2002-121414. The dyes represented by the general formulas (IV-1) to (IV-4) are listed as preferable examples, and specific examples include paragraph numbers [0052] to [0066] in JP-A No. 2001-181547. Examples thereof include the compounds described in paragraph Nos. [0079] to [0081] of Kai 2002-121414.
Particularly preferred dyes are phthalocyanine dyes represented by general formulas (CI) and (C-II) described in paragraphs [0133] to [0196] of JP-A No. 2002-121414, A phthalocyanine dye represented by formula (C-II) is preferred. Specific examples thereof include the compounds described in JP-A No. 2002-121414, paragraph numbers [0198] to [0201]. The oil-soluble dyes of the formulas (I) to (IV), (IV-1) to (IV-4), (CI) and (C-II) are not only cyan but also black ink or green ink. The ink may be used for any color ink.

These colorants are preferably added in an amount of 1 to 20% by mass in terms of solid content in the ink composition, and more preferably 2 to 10% by mass.
In the ink composition of the present invention, various additives can be used in combination with the essential components according to the purpose. These optional components will be described.

[Ultraviolet absorber]
In the present invention, an ultraviolet absorber can be used from the viewpoint of improving the weather resistance of the obtained image and preventing discoloration.
Examples of the ultraviolet absorber are described in JP-A-58-185679, JP-A-61-190537, JP-A-2-782, JP-A-5-97075, JP-A-9-34057, and the like. Benzotriazole compounds, benzophenone compounds described in JP-A No. 46-2784, JP-A No. 5-194843, US Pat. No. 3,214,463, etc., JP-B Nos. 48-30492 and 56-21141 Cinnamic acid compounds described in JP-A-10-88106, JP-A-4-298503, JP-A-8-53427, JP-A-8-239368, JP-A-10-182621, JP The triazine compounds described in JP-A-8-501291, Research Disclosure No. Examples thereof include compounds described in No. 24239, compounds that emit ultraviolet light by absorbing ultraviolet rays typified by stilbene and benzoxazole compounds, so-called fluorescent brighteners, and the like.
Although the addition amount is appropriately selected according to the purpose, it is generally about 0.5 to 15% by mass in terms of solid content.

[Sensitizer]
If necessary, a sensitizer may be added to the ink composition of the present invention for the purpose of improving the acid generation efficiency of the photoacid generator and increasing the photosensitive wavelength. Any sensitizer may be used as long as the photoacid generator is sensitized by an electron transfer mechanism or an energy transfer mechanism. Preferably, aromatic polycondensed compounds such as anthracene, 9,10-dialkoxyanthracene, pyrene and perylene, aromatic ketone compounds such as acetophenone, benzophenone, thioxanthone and Michlerketone, and heterocyclic compounds such as phenothiazine and N-aryloxazolidinone Is mentioned. The addition amount is appropriately selected according to the purpose, but is generally 0.01 to 1 mol%, preferably 0.1 to 0.5 mol%, based on the photoacid generator.

〔Antioxidant〕
An antioxidant can be added to improve the stability of the ink composition. Examples of the antioxidant include European published patents, 223739, 309401, 309402, 310551, 310552, 359416, and 3435443. JP, 54-85535, 62-262417, 63-113536, 63-163351, JP-A-2-262654, JP-A-2-71262, Examples thereof include those described in Kaihei 3-121449, JP-A-5-61166, JP-A-5-119449, US Pat. No. 4,814,262, US Pat. No. 4,980,275, and the like.
The addition amount is appropriately selected according to the purpose, but is generally about 0.1 to 8% by mass in terms of solid content.

[Anti-fading agent]
In the ink composition of the present invention, various organic and metal complex anti-fading agents can be used. Examples of the organic anti-fading agent include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, and heterocycles. Examples of the metal complex anti-fading agent include nickel complexes and zinc complexes. No. 17643, VII, I to J, No. 15162, ibid. No. 18716, page 650, left column, ibid. No. 36544, page 527, ibid. No. 307105, page 872, ibid. The compounds described in the patent cited in No. 15162 and the compounds included in the general formulas and compound examples of representative compounds described in JP-A-62-215272, pages 127 to 137 can be used. .
The addition amount is appropriately selected according to the purpose, but is generally about 0.1 to 8% by mass in terms of solid content.

[Conductive salts]
Conductive salts such as potassium thiocyanate, lithium nitrate, ammonium thiocyanate, and dimethylamine hydrochloride can be added to the ink composition of the present invention for the purpose of controlling ejection properties.

〔solvent〕
In order to improve the adhesion to the recording medium, it is also effective to add a very small amount of an organic solvent to the ink composition of the present invention.
Examples of the solvent include ketone solvents such as acetone, methyl ethyl ketone, and diethyl ketone, alcohol solvents such as methanol, ethanol, 2-propanol, 1-propanol, 1-butanol, and tert-butanol, and chlorine such as chloroform and methylene chloride. Solvents, aromatic solvents such as benzene and toluene, ester solvents such as ethyl acetate, butyl acetate and isopropyl acetate, ether solvents such as diethyl ether, tetrahydrofuran and dioxane, glycols such as ethylene glycol monomethyl ether and ethylene glycol dimethyl ether And ether solvents.
In this case, it is effective to add the solvent within a range that does not cause the problem of solvent resistance and VOC, and the amount is preferably 0.1 to 5% by mass, more preferably 0.1 to 3% by mass with respect to the whole ink composition. % Range.

[Polymer compound]
Various polymer compounds can be added to the ink composition of the present invention in order to adjust film physical properties. Examples of polymer compounds include acrylic polymers, polyvinyl butyral resins, polyurethane resins, polyamide resins, polyester resins, epoxy resins, phenol resins, polycarbonate resins, polyvinyl butyral resins, polyvinyl formal resins, shellacs, vinyl resins, acrylic resins. Rubber resins, waxes and other natural resins can be used. Two or more of these may be used in combination. Of these, vinyl copolymer obtained by copolymerization of acrylic monomers is preferred. Furthermore, a copolymer containing “carboxyl group-containing monomer”, “methacrylic acid alkyl ester”, or “acrylic acid alkyl ester” as a structural unit is also preferably used as the copolymer composition of the polymer binder.

[Surfactant]
A surfactant may be added to the ink composition of the present invention.
Examples of the surfactant include those described in JP-A Nos. 62-173463 and 62-183457. For example, anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalenesulfonates, fatty acid salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene / polyoxypropylene blocks Nonionic surfactants such as copolymers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts. An organic fluoro compound may be used in place of the surfactant. The organic fluoro compound is preferably hydrophobic. Examples of the organic fluoro compounds include fluorine surfactants, oily fluorine compounds (eg, fluorine oil) and solid fluorine compound resins (eg, tetrafluoroethylene resin). No. (columns 8 to 17) and those described in JP-A Nos. 62-135826.

In addition to this, for example, leveling additives, matting agents, waxes for adjusting film physical properties, polymerization to improve adhesion to a recording medium such as polyolefin or PET, and the like. It can contain a tackifier that does not obstruct.
As a tackifier, specifically, a high molecular weight adhesive polymer (for example, (meth) acrylic acid and an alkyl group having 1 to 20 carbon atoms) described in JP-A-2001-49200, 5-6p. An ester with an alcohol having, an ester of (meth) acrylic acid and an alicyclic alcohol having 3 to 14 carbon atoms, a copolymer comprising an ester of (meth) acrylic acid and an aromatic alcohol having 6 to 14 carbon atoms) Or a low molecular weight tackifying resin having a polymerizable unsaturated bond.

[Preferred physical properties of ink composition]
The ink composition of the present invention preferably has an ink viscosity of 20 mPa · s or less, more preferably 10 mPa · s or less at the temperature at the time of ejection in consideration of ejection properties. It is preferable to adjust and determine the composition ratio.

  The common surface tension of the ink composition of the present invention is preferably 20 to 40 mN / m, more preferably 25 to 35 mN / m. When recording on various recording media such as polyolefin, PET, coated paper, and non-coated paper, 20 mN / m or more is preferable from the viewpoint of bleeding and penetration, and 40 mN / m or less is preferable in terms of wettability.

The ink composition of the present invention thus adjusted is suitably used as an ink for inkjet recording. When used as an ink for ink jet recording, the ink composition is ejected onto a recording medium by an ink jet printer, and then the ejected ink composition is irradiated with active energy and cured to perform recording.
In the printed matter obtained with this ink, the image portion is cured by irradiation with active energy such as ultraviolet rays, and the strength of the image portion is excellent. Therefore, in addition to image formation with ink, for example, an ink receiving layer ( It can be used for various purposes such as formation of an image portion.

[Radical polymerization ink composition]
The radical polymerization ink composition contains (d) a radical polymerizable compound, (e) a polymerization initiator, and (f) a colorant. If desired, it may further contain a sensitizing dye, a co-sensitizer and the like.
Hereinafter, each component used for the radical polymerization ink composition will be sequentially described.

(D) [Radically polymerizable compound]
Examples of the radically polymerizable compound include compounds having an ethylenically unsaturated bond capable of addition polymerization as described below.

[Compound having an ethylenically unsaturated bond capable of addition polymerization]
Examples of compounds having addition-polymerizable ethylenically unsaturated bonds that can be used in the ink composition of the present invention include unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid Etc.) and an aliphatic polyhydric alcohol compound, an amide of the unsaturated carboxylic acid and an aliphatic polyamine compound, and the like.

  Specific examples of the monomer of an ester of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, and tetramethylene glycol. Diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol di Acrylate, Tetraethylene glycol diacrylate, Pentaerythritol diacrylate, Pentaerythritol triacrylate , Pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, polyester acrylate oligomer.

  Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, Hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- (3-methacryloxy 2-hydroxypro ) Phenyl] dimethyl methane, bis - [p- (acryloxyethoxy) phenyl] dimethylmethane. Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate Sorbitol tetritaconate, etc.

  Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate. Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate. Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate. Furthermore, the mixture of the above-mentioned ester monomer can also be mention | raise | lifted. Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexa. Examples include methylene bis-methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, and xylylene bismethacrylamide.

As another example, a vinyl compound containing a hydroxyl group represented by the following general formula (A) is added to a polyisocyanate compound having two or more isocyanate groups per molecule described in JP-B-48-41708. Examples thereof include vinyl urethane compounds containing two or more polymerizable vinyl groups in one molecule to which a monomer is added. CH ₂ = C (R) COOCH ₂ CH (R ′) OH (A) (where R and R ′ represent H or CH ₃ )
Further, as described in JP-A-51-37193, urethane acrylates, JP-A-48-64183, JP-B-49-43191, JP-B-52-30490, etc. Polyfunctional acrylates and methacrylates such as polyester acrylates and epoxy acrylates obtained by reacting an epoxy resin with (meth) acrylic acid can be used. Furthermore, Journal of Japan Adhesion Association vol.20, No. 7, pages 300 to 308 (1984) as photocurable monomers and oligomers can also be used. In the present invention, these monomers may be used in a chemical form such as a prepolymer, that is, a dimer, a trimer and an oligomer, or a mixture thereof and a copolymer thereof.

  The amount of the radical polymerizable compound used is usually 1 to 99.99%, preferably 5 to 90.0%, more preferably 10 to 70%, based on all components of the ink composition. Mass%).

(E) [Photoinitiator]
Next, the photopolymerization initiator used in the radical polymerization ink composition of the present invention will be described.
The photopolymerization initiator in the present invention is a compound that undergoes a chemical change through the action of light or interaction with the electronically excited state of a sensitizing dye to generate at least one of radicals, acids, and bases. It is.

  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, (to) azinium compounds, (thi) metallocene compounds, (li) active ester compounds, (nu) compounds having a carbon halogen bond, and the like.

(F) [Colorant] The same colorant as (c) described in the cationic polymerization ink composition can be used.
In the ink composition of the present invention, various additives can be used in combination with the essential components according to the purpose. These optional components will be described.
[Sensitizing dye]
In the present invention, a sensitizing dye may be added 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.
Polynuclear aromatics (eg, pyrene, perylene, triphenylene), xanthenes (eg, fluorescein, eosin, erythrosine, rhodamine B, rose bengal), cyanines (eg, thiacarbocyanine, oxacarbocyanine), merocyanines ( For example, merocyanine, carbomerocyanine), thiazines (eg, thionine, methylene blue, toluidine blue), acridines (eg, acridine orange, chloroflavin, acriflavine), anthraquinones (eg, anthraquinone), squalium (eg, squalium) ), Coumarins (eg 7-diethylamino-4-methylcoumarin).

[Co-sensitizer]
Further, the ink of the present invention may contain a known compound having a function of further improving sensitivity or suppressing polymerization inhibition by oxygen as a co-sensitizer.

  Examples of such co-sensitizers include amines such as MR Sander et al., “Journal of Polymer Society”, Vol. 10, page 3173 (1972), Japanese Examined Patent Publication No. 44-20189, Japanese Patent Laid-Open No. 51-82102. Publication, JP 52-134692, JP 59-138205, JP 60-84305, JP 62-18537, JP 64-33104, Research Disclosure 33825 Specifically, triethanolamine, p-dimethylaminobenzoic acid ethyl ester, p-formyldimethylaniline, p-methylthiodimethylaniline and the like can be mentioned.

  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 disulfide compounds, and specific examples include 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, 2-mercapto-4 (3H) -quinazoline, β-mercaptonaphthalene, and the like.

  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 Japanese Patent Application No. 6-191605 H, Ge-H compound, etc. are mentioned.

  Moreover, it is preferable to add 200-20000 ppm of a polymerization inhibitor from a viewpoint of improving storability. The ink for ink jet recording of the present invention is preferably ejected by heating and lowering the viscosity in the range of 40 to 80 ° C., and a polymerization inhibitor is preferably added to prevent clogging of the head due to thermal polymerization. Examples of the polymerization inhibitor include hydroquinone, benzoquinone, p-methoxyphenol, TEMPO, TEMPOL, and cuperon Al.

[Others]
In addition, known compounds can be used as necessary. For example, surfactants, leveling additives, matting agents, polyester resins for adjusting film properties, polyurethane resins, vinyl resins, acrylic resins. Resin, rubber resin, wax and the like can be appropriately selected and used. In order to improve the adhesion to a recording medium such as polyolefin or PET, it is also preferable to contain a tackifier that does not inhibit the polymerization. Specifically, high molecular weight adhesive polymers described in JP-A-2001-49200, 5-6p (for example, esters of (meth) acrylic acid and alcohols having an alkyl group having 1 to 20 carbon atoms) , An ester of (meth) acrylic acid and an alicyclic alcohol having 3 to 14 carbon atoms, a copolymer formed of an ester of (meth) acrylic acid and an aromatic alcohol having 6 to 14 carbon atoms), A low molecular weight tackifying resin having a saturated bond.

  It is also effective to add a trace amount of organic solvent in order to improve the adhesion to the recording medium. In this case, it is effective to add the solvent within a range that does not cause the problem of solvent resistance and VOC. % Range.

  In addition, as a means for preventing a decrease in sensitivity due to the light-shielding effect of the ink color material, it is also preferable to combine a cationic polymerizable monomer having a long polymerization initiator lifetime with a polymerization initiator to obtain a radical-cation hybrid type curable ink. One.

[Water-based ink composition]
The aqueous ink composition contains a water-soluble photopolymerization initiator that generates radicals by the action of a polymerizable compound and active energy. If desired, it may further contain a coloring material and the like.

[Polymerizable compound]
As the polymerizable compound contained in the aqueous ink composition of the present invention, a polymerizable compound contained in a known aqueous ink composition can be used.
A reactive material can be added to the water-based ink composition in order to optimize the formulation considering end-user characteristics such as curing speed, adhesion, and flexibility. Examples of such reactive materials include (meth) acrylate (ie, acrylate and / or methacrylate) monomers and oligomers, epoxides, and oxetanes.
Examples of acrylate monomers include phenoxyethyl acrylate, octyl decyl acrylate, tetrahydrofuryl acrylate, isobornyl acrylate, hexanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, polyethylene glycol diacrylate (e.g., tetraethylene glycol). Diacrylate), dipropylene glycol diacrylate, tri (propylene glycol) triacrylate, neopentyl glycol diacrylate, bis (pentaerythritol) hexaacrylate, ethoxylated or propoxylated glycols and polyol acrylates (e.g. propoxylated neopentyl glycol) Diacrylate, ethoxylated trimethylol proppant Acrylate), and mixtures thereof.
Examples of acrylate oligomers include ethoxylated polyethylene glycol, ethoxylated trimethylolpropane acrylate and polyether acrylate and ethoxylates thereof, and urethane acrylate oligomers.
Examples of methacrylates include hexanediol dimethacrylate, trimethylolpropane trimethacrylate, triethylene glycol dimethacrylate, diethylene glycol dimethacrylate, ethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, and mixtures thereof.
The amount of oligomer added is preferably 1 to 80% by weight, more preferably 1 to 10% by weight, based on the total weight of the ink composition.

[Water-soluble photopolymerization initiator that generates radicals by the action of active energy]
The polymerization initiator that can be used in the ink composition of the invention will be described. As an example, for example, a photopolymerization initiator having a wavelength of up to about 400 nm may be mentioned. As such a photopolymerization initiator, for example, a photopolymerization initiator represented by the following general formula (hereinafter referred to as TX), which is a substance having functionality in a long wavelength region, that is, a sensitivity to generate a radical upon receiving ultraviolet rays. In the present invention, it is particularly preferable to select and use them appropriately.

In the above general formulas TX-1 to TX-3, R2 represents — (CH ₂ ) _x — (x = 0 or 1), —O— (CH ₂ ) _y — (y = 1 or 2), substituted or unsubstituted Represents a phenylene group. When R2 is a phenylene group, at least one hydrogen atom in the benzene ring is, for example, a carboxyl group or a salt thereof, a sulfonic acid or a salt thereof, a linear or branched alkyl having 1 to 4 carbon atoms. May be substituted with one or more groups or atoms selected from a group, a halogen atom (fluorine, chlorine, bromine, etc.), an alkoxyl group having 1 to 4 carbon atoms, an aryloxy group such as a phenoxy group, and the like. . M represents a hydrogen atom or an alkali metal (for example, Li, Na, K, etc.). R3 and R4 each independently represents a hydrogen atom or a substituted or unsubstituted alkyl group. Examples of the alkyl group include, for example, a linear or branched alkyl group having about 1 to 10 carbon atoms, particularly about 1 to 3 carbon atoms. Moreover, as an example of the substituent of these alkyl groups, a halogen atom (a fluorine atom, a chlorine atom, an oxalic atom etc.), a hydroxyl group, an alkoxyl group (C1-C3 grade) etc. are mentioned, for example. M represents an integer of 1 to 10.

  Furthermore, in the present invention, a water-soluble derivative (hereinafter abbreviated as IC system) of a photopolymerization initiator Irgacure 2959 (trade name: manufactured by Ciba Specialty Chemicals) having the following general formula may be used. Specifically, IC-1 to IC-3 having the following formulas can be used.

[Prescription for clear ink]
The above-mentioned water-soluble polymerizable compound can be made into a clear ink by making it into the form of a transparent water-based ink without containing the above-mentioned coloring material. In particular, if it is prepared so as to have ink jet recording characteristics, a clear ink for water-based photocurable ink jet recording can be obtained. If such an ink is used, a clear film can be obtained because it does not contain a color material. Clear inks that do not contain color materials can be used for undercoats to give recording materials suitable for image printing, or for surface protection of images formed with ordinary inks, further decoration and gloss The use etc. for the overcoat for the purpose of provision etc. are mentioned. In the clear ink, colorless pigments or fine particles that are not intended for coloring can be dispersed and contained according to these applications. By adding these, it is possible to improve various properties such as image quality, fastness, and workability (handling property) of the printed matter in both the undercoat and the overcoat.

  Prescription conditions for application to such a clear ink include 10 to 85% of a water-soluble polymerizable compound as a main component of the ink, a photopolymerization initiator (for example, an ultraviolet polymerization catalyst), and the above water-soluble polymerization. It is preferable to prepare such that 1 to 10 parts by mass with respect to 100 parts by mass of the active compound and at least 0.5 part of the photopolymerization initiator is simultaneously contained with respect to 100 parts of ink.

[Material composition of colorant-containing ink]
When the above-described water-soluble polymerizable compound is used in an ink containing a coloring material, the concentration of the polymerization initiator and the polymerizable substance in the ink can be adjusted according to the absorption characteristics of the contained coloring material. preferable. As described above, the amount of water or solvent is in the range of 40% to 90%, preferably in the range of 60% to 75%, based on mass, as the blending amount. Furthermore, the content of the polymerizable compound in the ink is in the range of 1% to 30%, preferably in the range of 5% to 20%, based on the mass, with respect to the total amount of the ink. The polymerization initiator depends on the content of the polymerizable compound, but is generally in the range of 0.1 to 7%, preferably 0.3 to 5% on the mass basis with respect to the total amount of the ink.

  When a pigment is used as the color material of the ink, the concentration of the pure pigment in the ink is generally in the range of 0.3% by mass to 10% by mass with respect to the total amount of the ink. The coloring power of the pigment depends on the dispersion state of the pigment particles, but if it is in the range of about 0.3 to 1%, it becomes a range used as a light-colored ink. On the other hand, if it is more than that, it gives a concentration used for general color coloring.

1 is a schematic configuration diagram of a digital label printing apparatus according to a first embodiment of the present invention. FIG. 2 is a perspective view of an image forming unit and a smoothing unit in FIG. 1. It is a longitudinal cross-sectional view of the recording medium for label printing. The foil pressing state is shown, (a) is a cross-sectional view of the main part of the recording medium having large irregularities on the image surface, (b) is a cross-sectional view of the main part of the recording medium pressed without being smoothed, (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. It is a schematic block diagram of the digital label printing apparatus of the modification of the digital label printing apparatus of 1st Embodiment shown in FIG. It is a schematic block diagram of the digital label printing apparatus of 2nd Embodiment of this invention. It is a schematic block diagram of the digital label printing apparatus of 3rd Embodiment of this invention. It is a schematic block diagram of the digital label printing apparatus of 4th Embodiment of this invention. It is a schematic block diagram of the digital label printing apparatus of 5th Embodiment of this invention.

Explanation of symbols

20 Image forming unit (image forming means)
30 Smoothing means 31 Flat pressure member 32 Ultraviolet irradiation part (active energy irradiation means)
33 Varnish coater (transparent liquid supply means)
40 foil pressing means 45 foil 100 UV curable inkjet head digital label printing device (digital label printing device)
101 Digital Label Printing Device 200 Digital Label Printing Device 300 Digital Label Printing Device 330 Smoothing Unit 333 Inkjet Nozzle (Transparent Liquid Supply Unit)
400 Digital Label Printing Device 430 Smoothing Unit 431 Flat Pressure Member 431b Transparent Part 500 Digital Label Printing Device S Recording Medium (Continuous Sheet Recording Medium)

Claims (5)

In a digital label printing apparatus comprising: an image forming unit that forms an image on a continuous sheet recording medium based on a digital image signal; and a foil pressing unit that provides a foil to the recording medium after recording.
A digital label printing apparatus comprising a smoothing means for smoothing at least a foil donation range of image state ink on the recording medium upstream of the foil pressing means by a flat pressure member.   A transparent liquid supplying means for supplying the active energy curable transparent ink to the image surface on the recording medium; and an active energy irradiating means for irradiating the active energy curable transparent ink after the supply with the active energy. The digital label printing apparatus according to claim 1.   The digital label printing apparatus according to claim 2, wherein the transparent liquid supply means is a varnish coater.   The digital label printing apparatus according to claim 2, wherein the transparent liquid supply unit is an inkjet.   The planar pressure member has a transparent portion, and transmits the active energy of the active energy irradiation means disposed above the transparent portion to cure the active energy curable transparent ink. The digital label printing apparatus according to any one of the above.

Images