JP2010260360A - Digital label printing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital label printing apparatus which surely carries out an after-treatment of printing, and is high in productivity, low in cost and high in image quality. <P>SOLUTION: The digital label printing apparatus 100 includes an image forming means 20 for forming, based on a digital image signal, an image on a label-printing recording medium S of a continuous paper form, an after-treatment means 40 for carrying out the after-treatment on the recording medium S after recording, and an after-treatment step transportation rate changing means 54 for changing a transportation rate corresponding to a label position to be treated in the after-treatment means 40 based on a label edge-part data of the digital image signal. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a digital label printing apparatus, and more specifically, a digital that can reliably perform post-processing steps such as scrap removal for removing unnecessary portions from a label printed on a continuous paper-like label printing recording medium. The present invention relates to a label printing apparatus.

  Conventionally, labels have been produced by flexographic printing, offset printing, letterpress printing, and the like, but in recent years, digital printing machines using electrophotographic technology or ink jet technology have been announced due to demands for smaller lots and reduced waste paper. In addition, with the digitization of such printing, the flow of digitization is also in the post-process of label printing, and laser digital punching machines are being sold. According to laser processing, the degree of freedom of the punching shape is greatly improved, so the shape of the label is changed to a simple shape such as a conventional square or circle, and a complicated shape is required. .

JP 2002-226127 A

  However, if the shape of the label becomes complicated and the non-printing part is thin or has an acute angle part, the adhesive sheet for the non-printing part (unnecessary part) of the label, called scrap removal, which is a post-printing process, is mounted. In the process of peeling off, there was a problem that the thin non-printed part was broken, or the force at the time of peeling was concentrated on the acute angle part, causing damage from the acute angle part.

In addition, when laser processing is performed using a laser digital punching machine, it is necessary to apply a lot of energy to the thick part of the label. When laser processing is performed, uncut portions may be left in a thick portion, and there is a possibility that a failure may occur when the adhesive sheet of the non-printed portion (unnecessary portion) of the label is peeled off from the mount.
In this way, when a problem occurs in the post-printing process, the apparatus must be stopped and a repair operation must be performed each time, resulting in a problem of reduced productivity.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a digital label printing apparatus capable of performing label printing with high productivity, low cost, and high image quality so that post-processing of printing can be reliably performed. Is to provide.

The above object of the present invention is achieved by the following digital label printing apparatus.
(1) A digital label printing apparatus having image forming means for forming an image on a continuous paper-like label printing recording medium based on a digital image signal, and post-processing means for performing post-processing on the recording medium after recording In
A digital label printing apparatus comprising post-processing step transport speed changing means for changing a transport speed in accordance with a label processing position on the label in the post-processing means based on label edge data of the digital image signal.

  According to the digital label printing apparatus having the above-described configuration, the transport speed is changed by the post-processing process transport speed changing means in accordance with the label processing position on the post-processing means based on the label edge data of the digital image signal. Therefore, post-processing can be performed while transporting the label at the transport speed most suitable for each processing position on the label. As a result, post-processing can be performed reliably, troubles during post-processing can be prevented, and productivity can be greatly improved.

(2) The digital label printing apparatus according to (1), wherein the post-processing step conveyance speed changing unit changes the conveyance speed based on the label shape data of the label edge data.

  According to the digital label printing apparatus having the above-described configuration, the post-processing process conveyance speed changing unit changes the conveyance speed based on the label shape data of the label edge data, so that the optimum conveyance speed corresponding to the change in the label shape can be obtained. Post-processing can be performed to prevent a failure from occurring during post-processing.

(3) The post-processing step is composed of a die-cut for cutting the label shape and an unnecessary partial peeling portion for removing other than the label portion, and the post-processing step transport speed changing means is a label that is weak against unnecessary partial peeling with the label shape data. The digital label printing apparatus according to (2), wherein the recording medium conveyance speed is decreased at the partial position.

  According to the digital label printing apparatus having the above-described configuration, the post-processing step includes a die-cut for cutting a label shape and an unnecessary portion peeling portion that removes portions other than the label portion. Since the shape data is used to remove the recording medium at a label part position that is weak against unwanted part peeling, the recording medium is transported at a lower speed to prevent tearing and breakage of the label during post-processing (during scrap removal). It is possible to reliably remove unnecessary portions. As a result, it is possible to improve productivity by eliminating an apparatus stop caused by tearing or breakage of the label, and to provide the label at a low cost.

(4) The digital label printing apparatus according to (1), wherein the post-processing stroke conveyance speed changing unit changes the speed based on the image density data of the label edge data.

  According to the digital label printing apparatus having the above configuration, the post-process stroke conveyance speed changing unit changes the speed based on the image density data of the label edge data, so that the conveyance is performed at the optimum conveyance speed for the image density. It can be reliably post-processed.

(5) The post-processing step includes a laser cutter portion and an unnecessary portion peeling portion that removes portions other than the label portion, and the post-processing step conveyance speed changing means records in the portion where the density of the image density data of the label edge portion is high. The digital label printing apparatus according to (4), wherein the medium conveyance speed is decreased.

  According to the digital label printing apparatus having the above-described configuration, the post-processing step includes a laser cutter unit and an unnecessary portion peeling unit that removes other than the label portion, and the post-processing step conveyance speed changing means is an image of the label edge portion. Since the recording medium conveyance speed is slowed down in areas where the density data is dark, parts with high image density and therefore thick ink can be slowly cut at a slow speed with a laser cutter. Generation of uncut portions can be prevented.

  In particular, when the ink is an active energy curable ink such as an ultraviolet curable ink, a portion (color image portion) printed by overlapping a plurality of color inks is thick and therefore difficult to cut out, and thus has a thick portion. Laser processing of the recording medium at a low speed is effective from the viewpoint of preventing partial uncutting.

  ADVANTAGE OF THE INVENTION According to this invention, the post-process of printing can be implemented reliably and can provide the digital label printing apparatus which can print a label with high productivity and cheap and high quality.

1 is a schematic configuration diagram of a digital label printing apparatus according to a first embodiment of the present invention. The block diagram of the control part which controls the digital label printing apparatus in FIG. The longitudinal cross-sectional view of the recording medium for label printing. Sectional drawing of the die cutter by which the cutting blade was arrange | positioned on the cylindrical surface, and the perspective view which shows the state of the cut | interruption of the adhesive sheet by which this die cutter was rotated continuously and the cut | interruption was made. The perspective view which shows the state of the cut | interruption of the adhesive sheet by which the cut | interruption was put by the die cutter which rock | fluctuates and rotates. The schematic block diagram of the digital label printing apparatus which is 2nd Embodiment of this invention. The block diagram of the control part which controls the digital label printing apparatus in FIG. The schematic block diagram of the digital label printing apparatus which is 3rd Embodiment of this invention.

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 block diagram of a control unit that controls the digital label printing apparatus in FIG. 1, and FIG. 3 is a longitudinal section of a recording medium for label printing. FIG.

  In the digital label printing apparatus of the first embodiment, a continuous paper-like label printing recording medium is cut with a label shape by a die cutter, and an unnecessary portion of the adhesive sheet is peeled off from the mount (release paper) and removed. It is embodiment which performs a taking operation as a back process. In each of the following embodiments, an active energy curable digital label printing apparatus that uses an active energy curable ink that is cured by irradiation with active energy will be described as an example. It can be applied to the digital label printing apparatus.

  As shown in FIG. 1, the digital label printing apparatus 100 according to the first embodiment includes a transport unit 10 that transports a continuous paper-like label printing recording medium S, an image forming unit 20, a die cutter 30, and unnecessary part peeling. The waste removal part 40 which is a part, and the control means 50 are provided.

  As shown in FIG. 3, the continuous sheet-like recording medium S for label printing 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 that is a backing sheet. After the image is printed on the surface of the pressure-sensitive adhesive sheet 1 by the image forming means 20, it is peeled off from the release paper 2 and used.

  The transport unit 10 includes a supply roll 16 and a take-up roll 19 that are rotationally driven by a transport motor 18 (see FIG. 2), and supplies the continuous paper-like label printing recording medium S wound up in a roll shape to the supply roll 16. From the image forming unit 60 to the post-processing unit 61.

  The conveyance motor 18 is connected to a conveyance motor control unit 55 to be described later, and the rotation speed is controlled, and the conveyance speed of the continuous paper-like label printing recording medium S by the supply roll 16 and the take-up roll 19 is controlled. .

  A conveyance buffer unit 62 is provided between the image forming unit 60 and the post-processing unit 61, and a continuous paper-like label printing record caused by a difference in conveyance speed between the image forming unit 60 and the post-processing unit 61. The slack of the medium S is absorbed.

  The image forming unit 20 disposed in the image forming unit 60 includes ink jet heads (ink jet head units) 21Y, 21M, 21C, and 21B that discharge ink of each color, and a continuous paper-like shape on which the tip of the ink discharge unit is conveyed. It is arranged toward the label printing recording medium S. The inkjet heads 21Y, 21M, 21C, and 21B are full-line heads that have an array of width-direction lengths of the continuous paper-like label printing recording medium S, and employ piezo-type heads. The head drive control unit 52 of the control means 50 is connected to the inkjet heads 21Y, 21M, 21C, and 21B, and the ejection amount of each ink color is controlled.

  In addition, an active energy irradiation unit 22 as an active energy irradiation unit is disposed on the downstream side of each inkjet head 21Y, 21M, 21C, and 21B, and immediately after the ink rides on the continuous paper-like label printing recording medium S. Enough energy is given to cure properly. The arrangement of the active energy irradiation unit 22 is configured to irradiate only the ink on the continuous paper-like label printing recording medium S, and does not irradiate the ink discharge ports of the inkjet heads 21Y, 21M, 21C, and 21B. With this configuration, ink curing at the ejection port is prevented. In addition, it is preferable to perform a light reflection preventing treatment (for example, a matte black treatment) on each part in the vicinity of the active energy irradiation unit 22.

  The die cutter 30 is provided with a cut 1b of a desired label shape only in the adhesive sheet 1 of the printed continuous paper-like label printing recording medium S. The cylinder cutter 31 and the continuous paper-like label printing recording are provided. A receiving roller 32 disposed on the opposite side of the cylinder cutter 31 with respect to the medium S. In the cylinder cutter 31, a plurality of cutting blades 31a formed in a label shape are wound around the cylindrical surface of the cylinder 31b.

  The die cutter 30 sandwiches the continuous paper-like label printing recording medium S between the cylinder cutter 31 and the receiving roller 32, and swings intermittently at a speed synchronized with the conveying speed of the continuous paper-like label printing recording medium S. By rotating, the cutting blade 31a cuts the label-shaped cut 1b only in the adhesive sheet 1 of the continuous sheet-like label printing recording medium S (see FIG. 3).

  As shown in FIG. 4, it is rare that the circumferential length CL of the cylindrical surface of the cylinder 31b is an integral multiple of the length LL of the label L, in other words, the length CL1 of the cutting blade 31a. In the cylindrical surface of the cylinder 31b, a blank portion W where the cutting blade 31a is not provided is generated.

  Accordingly, when the die cutter 30 is continuously rotated to form the label-shaped cut 1b, a large space corresponding to the blank portion W is formed between the label group LB having the previous cut 1b and the label group LA having the current cut 1b. The unnecessary portion S1 is formed, and the continuous paper-like label printing recording medium S is wasted.

  In order to eliminate the formation of the unnecessary portion S1 in this way, the die cutter 30 is intermittently swung to continue to the rear end of the label group LB having the previous cut 1b as shown in FIG. A cut 1b can be made. Thereby, the generation of the unnecessary portion S1 between the label L groups LB and LA is eliminated, and the continuous paper-like label printing recording medium S can be used efficiently.

  Further, a UV varnish coater 45 can be disposed upstream of the die cutter 30, and the surface of the printed continuous paper-like label printing recording medium S is coated with UV varnish.

  The scrap removal part 40 peels and removes the unnecessary part of the adhesive sheet 1 that does not become the label L from the release paper 2 and discards it. The label L, which is a product, is wound around the take-up drum 19 together with the release paper 2 in a state of being attached to the release paper 2 to be a product.

  As shown in FIG. 2, the control means 50 includes a memory 51 for storing recording image data for ink ejection by the inkjet heads 21Y, 21M, 21C, and 21B, and recording image data for the inkjet heads 21Y, 21M, and 21C. , 21B, a head drive control unit 52, an image data analysis unit 53 for analyzing the shape of the label L, and a continuous paper-like label printing record based on the shape of the label L analyzed by the image data analysis unit 53 The conveyance speed changing means 54 for changing the conveyance speed of the medium S, the die cutter controller 56 for controlling the rotation speed of the die cutter 30 based on the conveyance speed changed by the conveyance speed changing means 54, and the conveyance speed changing means 54 are changed. A transport motor controller 55 that controls the rotational speed of the transport motor 18 based on the transport speed.

  The recording image data stored in the memory 51 can be input from an input unit 70 by a computer or the like (not shown) connected to the digital label printing apparatus 100.

  Next, the operation of the digital label printing apparatus 100 will be described. As shown in FIG. 1, a continuous paper-like label printing recording medium S fed from a supply roll 16 wound up in a roll shape is conveyed to an image forming unit 60 via a plurality of conveyance roller pairs 11 and 12. The The inkjet heads 21Y, 21M, 21C, and 21B are controlled by the head drive control unit 52, and the ink is ejected from the ink ejection unit at a timing that matches the transport speed of the continuous sheet-like label printing recording medium S. It discharges toward the recording medium S for label printing. The ink adhering to the continuous paper-like recording medium S for label printing is immediately irradiated with the active energy from the active energy irradiation unit 22 and cured, thereby being printed.

  The printed continuous paper-like label printing recording medium S is further transported to the post-processing unit 61 via the transport buffer unit 62, and the continuous paper-like label printing recording medium S is printed by the UV varnish coater 45. After the surface is coated with UV varnish, it is supplied to the die cutter 30 and only the adhesive sheet 1 is provided with a cut 1b in the shape of the label L.

  At this time, as described above, since the die cutter 30 cuts the cut 1b in the shape of the label L while swinging intermittently, the cut 1b can be continuously formed, and there is no wasted portion.

  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 40. On the other hand, the label L is wound on the take-up drum 19 together with the release paper 2 in a state of being stuck on the release paper 2 to become a product.

  The conveyance speed of the continuous paper-like label printing recording medium S in the post-processing unit 61 is changed based on the label shape data of the label edge data. That is, as shown in FIG. 2, the image data stored in the memory 51 is analyzed by the image data analyzing unit 53 for the shape of the label L of the label edge data, and the conveying speed changing unit 54 is analyzed by the image data analyzing unit 53. The conveyance speed is changed based on the shape of the label L of the analyzed label edge data. The conveyance speed changing means 54 stores in advance a conveyance speed optimum for post-processing for each shape of the label L, and from the shape of the label L of the analyzed label edge data and the stored conveyance speed, Change the transport speed to the optimal transport speed.

  The die cutter control unit 56 controls the rotational speed of the die cutter 30 based on the transport speed changed by the transport speed changing unit 54. Further, the transport motor control unit 55 controls the rotational speed of the transport motor 18 based on the transport speed changed by the transport speed changing unit 54 and transports the continuous sheet-like label printing recording medium S. At this time, the conveyance speed of the continuous sheet-like label printing recording medium S and the peripheral speed of the cutting blade 31a of the die cutter 30 are controlled to be the same speed.

  Specifically, the conveyance speed changing means 54 controls the recording medium conveyance speed to be slowed down at the label portion position that is weak against unnecessary part peeling by the shape data of the label L. As a result, it is possible to prevent tearing and breakage during scrap removal, and to reliably remove unnecessary portions other than the label portion.

  Conditions that are likely to cause tearing or breakage due to peeling of unnecessary parts are different depending on the material of the adhesive paper, but when the width of the unnecessary part is 5 mm or less, there is an acute angle part of 30 ° or less, etc. An optimum peeling speed determined in advance by a test under the above conditions is set in the conveyance speed changing means 54.

According to the digital label printing apparatus 100 of the present embodiment, the post-processing step is configured by the die-cut for cutting the label L-shaped cut 1b and the unnecessary part peeling portion 40 that removes portions other than the label L portion. Since the conveyance speed changing means 54 performs the peeling process by slowing the recording medium conveyance speed at the label portion position that is weak to the unnecessary part peeling with the label shape data, It is possible to prevent damage and to reliably remove unnecessary portions other than the label portion. As a result, it is possible to improve productivity by eliminating an apparatus stop caused by tearing or breakage of the label L, and to provide the label L at low cost.
(Second Embodiment)

  Next, a second embodiment of the digital label printing apparatus will be described with reference to FIGS. FIG. 6 is a schematic configuration diagram of a digital label printing apparatus according to the second embodiment of the present invention, and FIG. 7 is a block diagram of a control unit that controls the digital label printing apparatus in FIG. The digital label printing apparatus according to the second embodiment is the same as the digital label printing apparatus according to the first embodiment except that the die cutter is changed to a laser cutter. The explanation will be diverted.

  As shown in FIG. 6, the digital label printing apparatus 200 according to the second embodiment includes a laser cutter 35 in the post-processing unit 61 between the UV varnish coater 45 and the residue removing unit 40. The laser cutter 35 irradiates the continuous paper-like label printing recording medium S printed and conveyed in the same manner as the digital label printing apparatus 100 of the first embodiment by irradiating a laser to the adhesive sheet 1 and forms a label-like cut 1b. Insert. In laser processing, it is necessary to apply energy according to the thickness of the label L, and the greater the thickness of the label L, the more energy is required.

  On the other hand, when the active energy curable ink is used as the ink, the cured ink is formed on the pressure-sensitive adhesive sheet 1 so as to rise. The rising height of the cured ink is, for example, about 12 μm, and the color printing portion to which a plurality of (Y, M, C) inks are stacked and adhered is further increased. When an active energy curable ink is used, a label printing recording medium S that does not absorb ink at all is often used, and the raised height is increased as it is. Moreover, since a lot of ink adheres to the portion where the image density is high, the swell height is also high and thick. In addition, in the case of the thinnest thickness of the label printing recording medium S, it is about 12 μm, which is thinner than the ink thickness, and the influence is further increased.

  Next, the operation of the digital label printing apparatus 200 of this embodiment will be described. Similar to the digital label printing apparatus 100 of the first embodiment, the continuous paper-like label printing recording medium S fed from the supply roll 16 is conveyed to the image forming unit 60. The inkjet heads 21Y, 21M, 21C, and 21B eject ink toward the continuous paper-like label printing recording medium S at a timing that matches the transport speed from the ink ejection unit. The ink is immediately irradiated with active energy from the active energy irradiation unit 22 and cured.

  The printed continuous paper-like label printing recording medium S is further transported to the post-processing unit 61 via the transport buffer unit 62, and the continuous paper-like label printing recording medium S is printed by the UV varnish coater 45. After the surface is coated with UV varnish, a laser is irradiated from the laser cutter 35, and the cut 1b is made in the shape of the label L only on the adhesive sheet 1.

  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 40. On the other hand, the label L is wound around the product drum 19 together with the release paper 2 in a state of being stuck on the release paper 2 to become a product.

  The conveyance speed of the continuous paper-like label printing recording medium S in the post-processing unit 61 is changed based on the density of the image density data at the label edge. That is, as shown in FIG. 7, the image data stored in the memory 51 is analyzed for image density at the label edge by the image data analysis means 53, and the conveying speed changing means 54 is based on the image density at the label edge. Change the transport speed. The conveyance speed changing means 54 stores in advance the optimum post-processing conveyance speed corresponding to the image density. The image density of the label edge obtained by the image data analysis means 53, the stored conveyance speed, and the like. To change to the optimum transport speed.

  The transport motor control unit 55 controls the rotational speed of the transport motor 18 based on the transport speed changed by the transport speed changing unit 54 and transports the continuous sheet-like label printing recording medium S. Specifically, control is performed so as to reduce the recording medium conveyance speed at a position where the image density at the label edge is high. As a result, a portion having a high image density, that is, a portion where the label L is thick and difficult to be cut out by a laser is irradiated with a large amount of energy by slowing the conveying speed, and a label-shaped cut 1b is made in the adhesive sheet 1. .

  Conditions that are difficult to cut out by a laser are places where the ink film thickness is thick (especially ink that is difficult to absorb laser light), etc., and an optimum conveyance speed determined in advance by a test under each condition is supplied to the conveyance speed changing means 54. Is set.

According to the digital label printing apparatus 200 of the present embodiment, the post-processing process transport speed changing unit 54 decreases the recording medium transport speed in a portion where the density of the image density data at the label edge is high. A portion that is thick and therefore thick, such as an active energy curable ink, can be cut at a slower speed by the laser cutter 35, thereby preventing partial cutouts from occurring.
(Third embodiment)

  Next, a third embodiment of the digital label printing apparatus of the present invention will be described with reference to FIG. FIG. 8 is a schematic configuration diagram of a digital label printing apparatus according to the third embodiment of the present invention. The digital label printing apparatus of the third embodiment is the same as that of the second embodiment except that the image forming unit 60 and the post-processing unit 61 of the digital label printing apparatus of the second embodiment are configured as independent devices. Since it is the same as that of the digital label printing apparatus, the same parts are denoted by the same or corresponding reference numerals, and description thereof will be simplified or omitted.

  As shown in FIG. 8, the digital label printing apparatus 300 according to the third embodiment is a printing apparatus 160 in which a portion corresponding to the image forming unit 60 of the digital label printing apparatus 200 according to the second embodiment is independent. A portion corresponding to the post-processing unit 61 of the apparatus 200 is configured as an independent post-processing apparatus 161. Accordingly, the transport buffer unit 62 does not exist.

  The configurations of the printing device 160 and the post-processing device 161 are exactly the same as those of the image forming unit 60 and the post-processing unit 61 of the digital label printing device 200.

  In the digital label printing apparatus 300 according to the third embodiment, first, ink is ejected from the ink ejection units of the inkjet heads 21Y, 21M, 21C, and 21B toward the continuous paper-like label printing recording medium S by the printing apparatus 160. The active energy is irradiated from the active energy irradiation unit 22 and printed.

  The printed continuous paper-like label printing recording medium S is supplied to the post-processing device 161 and processed in exactly the same manner as the post-processing unit 61 of the digital label printing device 200 of the second embodiment. That is, based on the image density of the label edge analyzed by the image data analysis unit 53, the conveyance speed changing unit 54 changes the conveyance speed to the optimum conveyance speed. The conveyance motor control unit 55 controls the rotation speed of the conveyance motor 18 so as to achieve the changed optimum conveyance speed, and conveys the continuous paper-like label printing recording medium S. Specifically, control is performed so as to reduce the recording medium conveyance speed at a position where the image density at the label edge is high.

  According to the digital label printing apparatus 300 of the present embodiment, since the printing apparatus 160 and the post-processing apparatus 161 are configured as separate and independent apparatuses, respectively, a label printing process and a post-process such as scrap removal are performed. Can be performed as a separate operation, and post-processes of many 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 161 can correspond to a plurality of printing devices 160. Therefore, efficient processing is possible by installing the printing apparatus 160 and the post-processing apparatus 161 independently.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. For example, in the above-described embodiment, the full-line active energy curable digital label printing apparatus has been described as an example of the digital label printing apparatus. However, the present invention is not limited to this, and any other type of digital label printing is possible. It can also be applied to an apparatus and has 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 inkjet recording apparatus of the present invention, active energy irradiation 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, for 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 a 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 are susceptible to curling and deformation, such as heat-shrinkable PET film, OPS film, OPP film, ONy film, PVC film, etc., have the advantage that high-definition images 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 its alkylene oxide adducts, 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 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 in 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 herein 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, JP 2003-342503 A, and the like.

  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 (such as quinoline yellow lake); 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 dispersing 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 weight 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, and the problem of VOC (Volatile Organic Compound) 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.
The selection of pigment, dispersant, dispersion medium, dispersion conditions, and filtration conditions are set so that the average particle diameter of the pigment particles is within the above-mentioned preferable 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. Therefore, a so-called water-insoluble oil-soluble dye is 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 paragraph numbers [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 mentioned as preferable examples, and specific examples include paragraph numbers [0052] to [0066] of 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.
The addition amount is appropriately selected according to the purpose, but is generally about 0.5 to 15% by mass in terms of solid content.

[Sensitizer]
A sensitizer may be added to the ink composition of the present invention as necessary 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, 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. High molecular 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, if necessary, for example, leveling additives, matting agents, waxes for adjusting film physical properties, polymerization to inhibit the adhesion to recording media such as polyolefin and PET, and the like, The tackifier which does not do can be contained.
As the tackifier, specifically, a high molecular weight adhesive polymer described in JP-A-2001-49200, 5-6p (for example, (meth) acrylic acid and an alkyl group having 1 to 20 carbon atoms). An ester with an alcohol having, an ester of (meth) acrylic acid with an alicyclic alcohol having 3 to 14 carbon atoms, a copolymer comprising an ester of (meth) acrylic acid with an aromatic alcohol having 6 to 14 carbon atoms) And 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 uncoated 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 the compound having an addition polymerizable ethylenically unsaturated bond that can be used in the ink composition of the present invention include unsaturated carboxylic acids (for example, 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 an amide monomer of an aliphatic polyvalent amine compound and an unsaturated carboxylic acid 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.

Other examples include vinyls containing a hydroxyl group represented by the following general formula (A) in a polyisocyanate compound having two or more isocyanate groups per molecule described in JP-B-48-41708. Examples thereof include a vinylurethane compound 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, urethane acrylates as described in JP-A-51-37193, as described in 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%, and more preferably 10 to 70% with respect to all the components of the ink composition (where% is used herein) 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]
Furthermore, 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, p. 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. Examples thereof 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, 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.

  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.

  Further, in the present invention, a water-soluble derivative (hereinafter abbreviated as an 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 color material, the concentration of the polymerization initiator and the polymerizable substance in the ink can be adjusted in accordance with the absorption characteristics of the contained color material. preferable. As described above, the amount of water or solvent is in the range of 40% to 90%, preferably 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% on the mass basis with respect to the total amount of the ink. Although the polymerization initiator depends on the content of the polymerizable compound, it 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.

20 Image forming means 30 Die cutter 35 Laser cutter 40 Waste removal part (unnecessary part peeling part, post-processing means)
54 Conveying speed changing means (post-processing process conveying speed changing means)
DESCRIPTION OF SYMBOLS 100 Digital label printing apparatus 200 Digital label printing apparatus 300 Digital label printing apparatus L Label S Continuous paper-like label printing recording medium

Claims (5)

In a digital label printing apparatus having image forming means for forming an image on a continuous paper-like label printing recording medium based on a digital image signal, and post-processing means for performing post-processing on the recording medium after recording.
A digital label printing apparatus comprising post-processing step transport speed changing means for changing the transport speed in accordance with a label processing position on the label in the post-processing means based on label edge data of the digital image signal.   2. The digital label printing apparatus according to claim 1, wherein the post-processing step transport speed changing unit changes the transport speed based on label shape data of the label edge data.   The post-processing step is composed of a die-cut for cutting the label shape and an unnecessary partial peeling portion for removing the part other than the label portion, and the post-processing step transport speed changing means is at the label portion position weak against unnecessary partial peeling with the label shape data. The digital label printing apparatus according to claim 2, wherein the recording medium conveyance speed is decreased.   The digital label printing apparatus according to claim 1, wherein the post-process stroke conveyance speed changing unit changes the speed based on image density data of the label edge data.   The post-processing step includes a laser cutter portion and an unnecessary portion peeling portion that removes parts other than the label portion, and the post-processing step conveying speed changing means is a recording medium conveying speed in a portion where the density of the image density data at the label edge is high. The digital label printing apparatus according to claim 4, which slows down the printing speed.

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