JP5633136B2 - Inkjet recording device - Google Patents

Description

  The present invention relates to an image of an ink jet recording apparatus in which a photocurable ink is ejected onto a recording medium by an ink jet recording head, and the ink landed on the recording medium is irradiated with light to be cured to form an image on the recording medium. The present invention relates to a forming method and an ink jet recording apparatus.

  Conventionally, a plurality of colored (colored) ink recording heads (Y, M, C, K) and one transparent (colorless) ink recording head arranged in the recording medium conveyance direction (sub-scanning direction), and these An ultraviolet irradiation device disposed on both outer sides of the recording head, and a head unit formed by mounting the recording head and the ultraviolet irradiation device on a carriage in the main scanning direction, and a recording medium in the sub scanning direction, An ink jet recording apparatus that draws an image on a recording medium while moving each is known (see Patent Document 1). In this ink jet recording apparatus, colored ink is ejected and landed on a recording medium, cured by an ultraviolet irradiation device, then colorless ink is ejected, landed, and cured by an ultraviolet irradiation device, and the recording medium Clear coating is applied to the image drawn above.

JP 2006-289722 A

  However, in the ink jet recording apparatus described above, depending on the image data drawn on the recording medium, a portion where the colored ink is not ejected is generated on the recording medium, and the portion where the colored ink is landed and the portion where the colored ink is not landed Unevenness will be formed on the top. When colorless ink is ejected onto this recording medium and overcoating is performed, irregularities also occur on the surface of the colorless ink layer due to the irregularities on the recording medium where the colored ink landed and where it did not land, There was a problem that good gloss could not be obtained.

  An object of the present invention is to provide an image forming method of an ink jet recording apparatus and an ink jet recording apparatus capable of forming a coat layer having a good gloss on the surface of an image formed (drawn) on a recording medium.

  An image forming method of an ink jet recording apparatus of the present invention is an image forming method of an ink jet recording apparatus in which a desired image is formed on a recording medium by an ink jet recording head, and the first colored ink is discharged. A visible image forming step for forming a visible image on the recording medium, and a non-visible image forming step for discharging the colorless first colorless ink to form a non-visible image so as to fill a portion other than the visible image on the recording medium. And a coat layer forming step of discharging a colorless second ink to form a coat layer on the visible image and the invisible image.

  According to this configuration, since the recording surface of the recording medium on which the visible image and the invisible image are formed is filled with the first colored ink and the first colorless ink, unevenness due to the ink occurs on the recording medium. There is nothing. As a result, the second ink is ejected onto a base (a visible image and an invisible image) that has no unevenness, and thus a coat layer having good gloss without an unevenness can be formed. The first colorless ink and the second ink may be the same (same) or different.

  In this case, the first colored ink, the first colorless ink, and the second ink are photocurable inks, and the first colored ink constituting the visible image is used between the visible image forming step and the coat layer forming step. A first colored semi-curing step for semi-curing, a first colorless semi-curing step for semi-curing the first colorless ink constituting the non-visible image between the invisible image forming step and the coat layer forming step; It is preferable to further include a second semi-curing step of semi-curing the second ink constituting the coat layer after the forming step.

  The inkjet recording apparatus of the present invention forms a desired image on a recording medium by ejecting photocurable ink from the recording unit while moving the inkjet recording unit relative to the recording medium. A first recording unit that ejects a colored first colored ink and ejects a colorless first colorless ink, a second recording unit that ejects a colorless second ink, and a first colored ink, the inkjet recording apparatus And an image semi-light curing part for semi-curing the first colorless ink, a coat layer semi-light curing part for semi-curing the second ink, a first recording part, a second recording part, an image semi-light curing part, and a coat layer half A control unit that controls the photocuring unit, the control unit ejecting the first colored ink to form a visible image on the recording medium, and ejecting the first colorless ink to visualize the visible image on the recording medium. Other than filling An image forming operation for forming a non-visible image, an image semi-curing operation for semi-curing the first colored ink constituting the visible image and the first colorless ink constituting the non-visible image, and discharging the second ink. The coating layer forming operation for forming the coating layer on the visible image and the non-visible image and the coating layer semi-curing operation for semi-curing the second ink constituting the coating layer are performed.

  According to these configurations, the visible image (first colored ink) and the non-visible image (first colorless ink) are semi-cured to control the wetting and spreading of the ink droplets landed on the recording medium. The size of the ink droplet can be made uniform. Thereby, it is possible to prevent the ink droplets from being mixed (color mixture). Furthermore, the surface of the visible and invisible image is flattened. By ejecting the second ink onto these images, a coat layer without unevenness can be formed. Similarly, a beautiful gloss can be obtained by semi-curing the coat layer (second ink) and uniformizing the size of each ink droplet. In the semi-curing of the coating layer, by adjusting the irradiance of light and adjusting the wetting and spreading of the second ink, any gloss adjustment such as matte (matte) or glossy (glossy) is possible. Become.

  In this case, in the second semi-curing step, it is preferable to perform semi-curing at a lower irradiance than in the first colored semi-curing step and the first colorless semi-curing step.

  Similarly, the control unit preferably performs the semi-curing in the coat layer forming operation with an irradiance lower than that in the image semi-curing operation.

  According to these configurations, each ink droplet of the second ink constituting the coat layer does not cure to the central portion but spreads wet. As a result, a coat layer having a smooth surface without irregularities on the visible image and the invisible image is formed, and a more beautiful gloss can be given to the image on the recording medium.

  Moreover, in this case, it is preferable to further include a main curing step in which the visible image, the invisible image, and the coat layer are finally cured after the second semi-curing step.

  Similarly, the image forming apparatus further includes a main curing unit for main curing the visible image, the invisible image, and the coating layer, and the control unit controls the main curing unit and performs the main curing operation after the semi-curing operation of the coating layer. Is preferred.

  According to these configurations, after the coat layer having the desired gloss is formed, that is, after all the image formation (drawing) is completed, all the images (visible image, invisible image, coat layer) are completely transferred. By curing (main curing), it is possible to reliably fix the entire image on the recording medium. Further, since each ink on the recording medium has already been semi-cured, the main curing step (main curing operation) is completed in a short time. Thereby, the mechanism required for the main curing can be configured with a small and lightweight one.

  In this case, the visible image forming step and the invisible image forming step are performed in parallel, and the first colored semi-curing step and the first colorless semi-curing step are simultaneously performed on the visible image and the non-visible image. Preferably, it is done.

  According to this configuration, the visible image and the invisible image can be formed in a short time, and the visible image and the invisible image can be semi-cured in a short time. Thereby, the time required for the image forming (drawing) process on the recording medium can be shortened.

  In the case of this ink jet recording apparatus, a carriage on which the first recording unit, the second recording unit, the image semi-light curing unit, the coat layer semi-photo curing unit, and the main curing unit are mounted, and the carriage with respect to the recording medium in the main scanning direction. It is preferable that the apparatus further includes a moving unit that relatively moves in the sub-scanning direction.

  In this case, the carriage includes a recording carriage on which the first recording unit and the second recording unit are mounted, a photocuring carriage on which the image semi-light curing unit, the coat layer semi-light curing unit, and the main curing unit are mounted; It is preferable to have.

  According to these configurations, each recording unit and each curing unit can be moved at the same time, so that the formation operation for each image and the semi-curing operation (and the main curing operation) for each image are the same movement. Sometimes it can be carried out continuously. Thereby, it is possible to efficiently form an image on the recording medium. Further, since each recording unit and each curing unit can be exposed to the entire image forming area on the recording medium by moving the carriage, each recording unit and each curing unit need only be small, and the entire apparatus Can be reduced in size. Further, since the recording carriage and the photocuring carriage are separated, heat generated on the photocuring carriage side can be prevented from being transmitted to the recording carriage side. Therefore, it is possible to prevent changes in the discharge amount of each ink, distortion of the recording carriage, and the like due to the influence of heat. As a result, problems such as displacement of the landing positions of the respective inks on the recording medium can be prevented, and high-precision images and the like can be formed.

  In this case, the first recording unit includes a plurality of first colored recording heads that discharge first colored inks of a plurality of colors, and a single first colorless recording head that discharges first colorless ink. It is preferable.

  In this case, it is preferable that the plurality of first colored recording heads and the single first colorless recording head are arranged side by side in the main scanning direction.

  According to these configurations, the first colored ink and the first colorless ink can be ejected in the same main scanning. Thereby, a visible image and an invisible image can be formed in a short time.

  In this case, it is preferable that the second recording unit is disposed downstream of the first recording unit in the sub-scanning direction.

  In this case, it is preferable that the second recording unit has a single second recording head that discharges the second ink.

  According to these configurations, the range in which the first colored ink and the first colorless ink are ejected while moving the first recording unit in the main scanning direction and landed on the recording medium is relatively downstream in the sub-scanning direction. The second ink is ejected while moving the second recording portion in the main scanning direction. Accordingly, the discharge of the first colored ink and the first colorless ink and the discharge of the second ink can be performed in parallel and continuously in the same main scanning, and the visible image, the invisible image, and the coat can be performed. A layer can be formed efficiently.

  In this case, it is preferable that the image half-light curing unit has an image half-light curing unit disposed outside at least one of the first recording units in the main scanning direction.

  In this case, it is preferable that the coat layer semi-light curing portion has a coat layer semi-light curing unit disposed outside at least one of the second recording portions in the main scanning direction.

  According to these configurations, for example, in the case of a configuration in which the first recording unit is reciprocated in the main scanning direction, light is emitted from the image semi-light curing unit immediately after discharging the first colored ink and the first colorless ink during the forward movement. Semi-curing can be performed by irradiation. In addition, each ink can be discharged only during the forward movement, and semi-curing can be performed during the backward movement. Thereby, the time until semi-curing of each ink can be controlled, and each surface roughness of a visible image, a non-visible image, and a coat layer can be set arbitrarily. If semi-curing is performed immediately after landing on the recording medium, the surface becomes rough.

  In this case, it is preferable that the main curing unit is disposed on the downstream side in the sub-scanning direction with respect to the second recording unit.

  According to this configuration, after the first colored ink, the first colorless ink, and the second ink have landed on the recording medium, the landed area of these inks moves relatively downstream in the sub-scanning direction. The main curing is performed by irradiating light while the main curing unit moves in the main scanning direction. Thereby, the ejection of each ink and the main curing can be performed in parallel and continuously in the same main scanning, and the visible image, the invisible image, and the coat layer are efficiently fixed on the recording medium. Can do.

FIG. 2 is a plan view (a) and a side view (b) schematically showing the inside of the ink jet recording apparatus according to the present embodiment (first embodiment). It is the top view (a) and side view (b) of a carriage apparatus. It is the top view which showed typically the head unit and photocuring unit of a carriage apparatus. FIG. 2 is a front and back perspective view schematically showing a recording head. FIG. 4 is a front view and a side view of a recording carriage and a carriage base. It is the top view (a) of a carriage apparatus, a side view (b), and the elements on larger scale (c) of the optical gap adjustment means. 3 is a flowchart of an image forming method according to the present embodiment. It is explanatory drawing (side view) which showed typically a mode that a visible image, an invisible image, and a coat layer were formed in the image forming method which concerns on this embodiment. It is explanatory drawing (plan view) which showed typically a mode that a visible image, an invisible image, and a coat layer were formed in the image forming method which concerns on this embodiment.

  Hereinafter, an ink jet recording apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings. This ink jet recording apparatus discharges ultraviolet curable ink from a recording head to a recording medium, and then irradiates ultraviolet rays from an ultraviolet irradiator to cure the ultraviolet curable ink that has landed on the recording medium. An image is formed (drawn).

(First embodiment)
As shown in FIG. 1, the inkjet recording apparatus 1 has a carriage device 2 on which a head unit 21 having a plurality of inkjet recording heads 30 and a photocuring unit 22 are mounted, a carriage device 2 and a recording medium W relative to each other. Movably moving means 3, medium supplying means 4 on which the recording medium W before drawing is set, and a plurality of recording heads 30 are supplied with a plurality of colors of ultraviolet curable ink (hereinafter referred to as “ink”). And an ink supply unit 5 for controlling the image forming process by the ink jet recording apparatus 1.
Although not shown, maintenance means for preventing nozzle clogging or the like of each recording head 30 is disposed on the home position H side (lower side in FIG. 1A) of the carriage device 2. . In this maintenance means, a capping unit that seals the nozzle formation surface of each recording head 30, a suction unit that forcibly sucks ink from each recording head 30, and the formation surface of the nozzle hole 36 of each recording head 30 are wiped off. And a wiping unit.

  As shown in FIG. 1, the moving unit 3 includes a head moving mechanism 11 that moves the carriage device 2 in the main scanning direction (hereinafter referred to as “X-axis direction”) and the recording medium W in the sub-scanning direction (hereinafter referred to as “ And a medium feeding mechanism 12 that moves the recording medium W to a position facing the carriage device 2 (drawing area DA).

  The head moving mechanism 11 includes a first guide shaft 13 and a second guide shaft 14 that support the carriage device 2 so as to be movable in the X-axis direction, a servo motor 15 that is a drive source for moving the carriage device 2, and a servo motor 15. And a belt transmission mechanism 16 that reciprocates the carriage device 2 in the X-axis direction.

  The belt transmission mechanism 16 is connected to the servomotor 15 and is disposed at one end in the X-axis direction, a driven pulley 16b disposed at the other end in the X-axis direction, a drive pulley 16a, And an endless timing belt 16c spanned between the driven pulleys 16b. A base portion of the carriage device 2 is connected to one portion of the timing belt 16c via a belt fixing portion 62, which will be described later. When the servo motor 15 rotates forward and backward, the carriage device 2 is moved to the X axis via the timing belt 16c. Reciprocates in the direction.

  The first guide shaft 13 is an axis having an upper portion formed in a semicircular cross section, and the recording medium W supplied to the drawing area DA is arranged in the width direction (X-axis direction) on the upstream side of the drawing area DA in the Y-axis direction. It is arrange | positioned so that it may cross. Although omitted in the drawing, the first guide shaft 13 is supported on an apparatus frame (not shown) by a plurality of support members in the extending direction, and vertical deflection is prevented. Similarly, the second guide shaft 14 is a shaft having a substantially rectangular cross section, and is disposed in parallel to the first guide shaft 13 on the downstream side in the Y-axis direction of the drawing area DA. The lengths of the first guide shaft 13 and the second guide shaft 14 are set in accordance with the maximum width of the recording medium W that can be supplied. The carriage device 2 is supported on the first guide shaft 13 on the base side and on the second guide shaft 14 on the tip side, and is guided on the first guide shaft 13 and the second guide shaft 14 so as to support the X axis. Reciprocates in the direction.

  The servo motor 15 can control the position of the carriage device 2 in the X-axis direction. The servo motor 15 is on the side opposite to the home position H of the carriage device 2 (upper side in FIG. 1A), and the drive shaft is in the Y-axis direction. It is arrange | positioned toward the upstream. The carriage device 2 reciprocates along the first guide shaft 13 and the second guide shaft 14 via the timing belt 16c by forward and reverse rotation driving of the servo motor 15. Then, the servo motor 15 controls the carriage device 2 that moves on the recording medium W (the drawing area DA) in the X-axis direction so as to have a constant speed.

  The medium feeding mechanism 12 includes a platen 17 that supports the recording medium W from the back surface (non-recording surface) side, a feed roller 18 that contacts the recording medium W with the back surface, and feeds the recording medium W in the Y-axis direction, and the recording medium W. A medium pressing roller 19 (see FIG. 1B) that faces the feed roller 18 and a feed motor (not shown) that rotates the feed roller 18 and intermittently feeds the recording medium W. The recording medium W is intermittently fed with a length corresponding to the length of the nozzle row NL (see FIG. 4B) of the recording head 30 as one pitch.

  A plurality of small holes (not shown) are formed in a matrix (or zigzag) on the surface of the platen 17 so as to penetrate the back surface, and a suction fan (not shown) is provided below the platen 17. It has been. By rotating the suction fan, a suction force acts on the recording medium W on the platen 17 through a plurality of small holes, and the recording medium W is positioned and fixed on the platen 17 with uniform flatness. The As a result, since the drawing process can be performed on the recording medium W without distortion, it is possible to form a highly accurate image with no deviation in the ink landing position.

  The feed roller 18 and the medium presser roller 19 are located below the first guide shaft 13, that is, upstream of the drawing area DA in the Y-axis direction. The medium pressing roller 19 is a driven roller that rotates as the recording medium W is conveyed by the rotation of the feeding roller 18, and presses the recording medium W on the feeding roller 18 from above. That is, the feeding roller 18 and the medium pressing roller 19 are each constituted by a nip roller including a driving roller and a driven roller, and feed the recording medium W when the movement of the carriage device 2 is stopped. A paper discharge roller that feeds the recording medium W while performing slip rotation may be provided on the downstream side of the platen 17.

  The medium supply unit 4 is set with a recording medium W to be drawn and serves as a supply source of the recording medium W. The form of the recording medium W used in the present embodiment may be any form such as a roll or a cut sheet, and is not particularly shown, but the former recording medium W is a reel-to-reel paper. The latter recording medium W is fed one by one from the paper cassette by the paper feed roller. The recording medium W can be made of a material such as paper (plain paper, glossy paper, etc.), cloth (nonwoven fabric), resin, metal, glass, or the like.

  The ink supply means 5 is composed of a plurality of ink packs 5a each filled with colored or colorless ink, and each ink pack 5a is connected to each recording head 30 via an ink supply channel (not shown). ing. The ink of each color is supplied to each recording head 30 through each ink supply channel by pressurizing (atmospheric pressure) each ink pack 5a from the outside. Each ink supply channel and each recording head 30 are covered with a film heater (not shown) for heating the ink flowing through each ink supply channel. Each color ink is heated by a film heater, adjusted to a predetermined viscosity, and supplied to each recording head 30.

  The ultraviolet curable ink is roughly classified into a radical polymerization type ink containing a radical polymerizable compound and a cationic polymerization type ink containing a cationic polymerizable compound as a polymerizable compound. May be. Further, the ultraviolet curable ink used in the present embodiment includes cyan (C), magenta (M), yellow (Y), black (K), orange (Or), green (Gr), light magenta (LM), Although there are 10 colors of light cyan (LC), white (W), and clear (CL), the color (color) and the number of colors are not limited to this.

  Next, the carriage device 2 will be described in detail with reference to FIGS. As shown in FIG. 2, the carriage device 2 includes a head unit 21 that ejects ink onto the recording medium W, a photocuring unit 22 that cures ink landed on the recording medium W, and a first guide shaft 13. The carriage base 23 slidably supported, the second guide shaft 14, the support frame 24, which is slidably supported by the second guide shaft 14, and the photocuring unit 22 are supported by the support frame 24. And a plurality of support members 25 for suspending. The carriage device 2 faces the recording medium W fixed on the platen 17 and ejects ink from the head unit 21 onto the recording medium W while reciprocating in the X-axis direction by the head moving mechanism 11. The ink that has landed on the recording medium W is cured by the curing unit 22.

  The carriage device 2 also has a head gap adjusting means 26 for adjusting the gap between the head unit 21 and the recording medium W (see FIG. 5), and the roll angle of the head unit 21 (parallelism with the recording medium W). Parallelism adjusting means 27 for adjusting (see FIG. 5), and optical gap adjusting means 28 for adjusting the gap between the photocuring unit 22 and the recording medium W (see FIG. 6) are provided.

  As shown in FIGS. 2 and 3, the head unit 21 includes a first recording unit 31 having a plurality of recording heads 30 that discharge colored and colorless inks to the recording medium W, and an arbitrary recording medium W. A second recording unit 32 having one recording head 30 (second recording head 32a) for discharging the ink, and a recording carriage on which the first recording unit 31 and the second recording unit 32 are mounted separately in the Y-axis direction. 33.

  As shown in FIG. 4, the recording head 30 ejects ink by a so-called ink jet method, and is connected to the ink supply flow path described above, and a pump unit 34 to which ink is supplied, and a nozzle connected to the pump unit 34. Plate 35. Two nozzle rows NL are arranged in parallel to each other on the nozzle surface of the nozzle plate 35, and each nozzle row NL is composed of a large number of nozzle holes 36 arranged at an equal pitch. The number of nozzle rows NL and the number of nozzle holes 36 are arbitrary. Moreover, the pump part 34 is formed in two each so as to correspond to the nozzle row NL of each row. The recording head 30 is connected to the above-described control means 6 via a flexible flat cable (not shown), and the drive waveform output from the control means 6 is applied to the piezoelectric element (not shown) of the pump unit 34. As a result, ink is ejected from each nozzle hole 36.

  As shown in FIGS. 2 and 3, the first recording unit 31 is configured so that the nozzle array NL is directed in the Y-axis direction and the 10 recording heads 30 are arranged in a line at equal intervals in the X-axis direction. It is configured to be fixed to one head plate 37a. The ten recording heads 30 mounted on the first recording unit 31 include a plurality of first colored recording heads 31a that discharge colored (C, M, Y, K, Or, Gr, LM, LC, W) inks. And a single first colorless recording head 31b that discharges colorless (CL) ink are arranged side by side in the X-axis direction. In this embodiment, the inks of C, M, Y, K, Or, Gr, LM, LC, W, CL are applied to the recording head 30 (each first colored recording head 31a and the first colorless recording head from the upper end in FIG. 31 b), each recording head 30 is adapted to eject ink of each color. Note that the number of recording heads 30 is arbitrary, and the order of the colors of ink to be supplied is also arbitrary.

  On the other hand, the second recording unit 32 is configured such that a single recording head 30 (hereinafter referred to as a second recording head 32a) is fixed to the second head plate 38a with the nozzle row NL directed in the Y-axis direction. ing. The number of the second recording heads 32a is arbitrary. However, although details will be described later, in consideration of cantilever support of the recording carriage 33, suppression of mist generation, and the like, the number is preferably smaller than the number mounted on the first recording unit 31, and one or two is optimal. It is.

  The recording carriage 33 includes a first head holding portion 37 formed in a square shape having a long side in the X-axis direction, a second head holding portion 38 formed in a square shape smaller than the first head holding portion 37, and a first head. The holding portion 37 is integrally formed with a pair of standing portions 39 (see FIG. 5) standing on both ends in the X-axis direction. The second head holding part 38 is formed so as to protrude from the center in the X axis direction toward the downstream side in the Y axis direction of the first head holding part 37. That is, the recording carriage 33 is formed in a step shape in the plane.

  The first head holding portion 37 has a first head opening 37b facing a first head plate 37a in which a plurality of first colored recording heads 31a and first colorless recording heads 31b are positioned and fixed in the thickness direction (Z-axis direction). It is formed through. Similarly, in the second head holding portion 38, a second head opening 38b facing the second head plate 38a on which the second recording head 32a is positioned and fixed is formed penetrating in the thickness direction. In addition, one (three in total) positioning pins P stand in the vicinity of the first head opening 37b and the second head opening 38b. Each positioning pin P is fitted into a positioning hole (not shown) of the first head plate 37a and the second head plate 38a, so that the first head plate 37a is second with respect to the first head holding portion 37. The head plate 38a is fixed to the second head holding portion 38 in a state of being positioned in the X-axis direction, the Y-axis direction, and the yawing direction (three screws). Thus, the first recording unit 31 and the second recording unit 32 are assembled and mounted on the recording carriage 33, and the nozzle plate 35 (nozzle surface) of each recording head 30 is conveyed onto the platen 17. It faces the recording medium W.

  The recording carriage 33 is cantilevered by the carriage base 23 on the upstream side in the Y-axis direction of the first head holding portion 37, and the downstream side in the Y-axis direction of the second head holding portion 38 is a free end. That is, in the direction away from the first guide shaft 13, the recording heads 30 are arranged in ascending order. In this way, by making the head unit 21 cantilevered, adjustments specific to the head unit 21 such as gap adjustment and parallelism adjustment of the head unit 21 with respect to the recording medium W can be easily performed with high accuracy. Moreover, since the recording unit 30 with a large number of recording heads 30 is provided on the first guide shaft 13 side, the head unit 21 can be stably moved with little influence of inertia and can be started and stopped. Vibration due to inertia can be prevented. As a result, blurring and overrun of the recording carriage 33 can be suppressed, and no deviation occurs in the ink landing position on the recording medium W, so that highly accurate image formation (drawing) is possible. .

  As shown in FIGS. 2 and 3, the photocuring unit 22 includes a first semicuring unit 41 (image semiphotocuring unit) for semicuring the ink ejected by the first recording unit 31, and a second recording unit 32. A second semi-curing portion 42 (coat layer semi-curing portion) for semi-curing the ejected ink, and a main curing means 43 (main curing portion) for main-curing the ink ejected by the first recording portion 31 and the second recording portion 32. And a photocuring carriage 44 on which the first semicuring portion 41, the second semicuring portion 42, and the main curing means 43 are mounted.

  The first semi-curing unit 41 has a pair of first semi-curing means 45 located at both ends of the first recording unit 31 in the X-axis direction, and the first recording unit is reciprocated in the X-axis direction. The ink droplets are discharged from the ink 31 and land on the recording medium W. Similarly, the second semi-curing unit 42 has a pair of second semi-curing means 46 positioned at both ends of the second recording unit 32 in the X-axis direction, and landed on the recording medium W by the second recording unit 32. Facing each ink drop. The first semi-curing unit 41 and the second semi-curing unit 42 semi-cure the ink droplets that have landed on the recording medium W, thereby suppressing the wetting and spreading of the ink droplets on the recording medium W and transporting the recording medium W. Sometimes it prevents ink droplets from flowing out. Thereby, it is possible to prevent ink droplets from being mixed (color mixing) on the recording medium W, and to align each ink droplet to a certain size. Here, semi-curing means partial curing of ink droplets, which means a partially cured but not completely cured state. It is in a state where it has been cured in a state where it is not mixed with the droplets to such an extent that it does not fade visually and is smooth so that the surface has some glossiness.

  The main curing unit 43 is located downstream of the second recording unit 32 in the Y-axis direction, and is semi-cured by the first semi-curing unit 41 and the second semi-curing unit 42 along with the reciprocating movement in the X-axis direction. Facing each ink drop. The main curing unit 43 completely cures the inside of the landed ink droplet and fixes it on the recording medium W. Therefore, the irradiance (illuminance) of the main curing means 43 is set higher (stronger) than the first semi-cured portion 41 and the second semi-cured portion 42. The main curing unit 43 is provided on the most downstream side of the carriage device 2, and after the image is drawn by the first recording unit 31 and the second recording unit 32, the ink droplets that form the image are main cured. Let In addition, since the ink droplets on the recording medium W have already been semi-cured, the main curing unit 43 can be configured with a small and lightweight one having a relatively low output.

  Each of the first semi-curing means 45, each second semi-curing means 46, and the main curing means 43 has substantially the same structure, and a light irradiating unit 51 composed of a plurality of LEDs (Light Emitting Diodes) that emit ultraviolet rays. And a cooling unit 52 for cooling the light irradiation unit 51. The light irradiation unit 51 is a so-called LED array in which a plurality of chip-type ultraviolet LEDs are arranged in a matrix (or zigzag), and constitutes a surface light source as a whole. The first semi-curing means 45, the second semi-curing means 46, and the main curing means 43 have a width (length in the Y-axis direction) substantially the same as the length of the nozzle row NL of the recording head 30. The length in the X-axis direction is designed so as to obtain a predetermined irradiance in relation to the moving speed in the X-axis direction.

  The cooling unit 52 includes a heat sink 53 that is in close contact with the upper surface of the light irradiation unit 51, and a cooling fan 54 that blows air (air) toward the heat sink 53. The heat sink 53 is a so-called fin type, and the plurality of standing fins 53a extend in the X-axis direction and are arranged at equal intervals in the Y-axis direction. The heat sink 53 is covered with a cover 53b, and a cooling fan 54 is fixed to an opening formed on the upper surface of the cover 53b. The cooling fans 54 are respectively located on the head unit 21 side, and the air blown by each cooling fan 54 is exhausted (exhaust heat) to the outside along the fins 53a while absorbing heat from the fins 53a of the heat sink 53. The Thereby, since the heat generated from each light irradiation unit 51 is effectively exhausted, it is possible to prevent the light emission performance of the light irradiation unit 51 from being deteriorated by heat and to stably photocure the ink. Although details will be described later, the exhaust (exhaust heat) from the cooling fan 54 is blocked by a rib 58 erected on the recording carriage 33 side of the photocuring carriage 44.

  The photocuring carriage 44 includes a pair of carriage side portions 55 that are symmetrically positioned on both sides of the recording carriage 33 in the X-axis direction, and a carriage connecting portion 56 that connects the pair of carriage side portions 55. Since the photocuring carriage 44 is integrally formed of a resin having reinforcing rib portions appropriately disposed, it can be configured to be light and inexpensive while maintaining sufficient strength. It is also possible to suppress the propagation of heat.

  Each carriage side portion 55 has two holding portions 57 that hold the first semi-curing means 45 and the second semi-curing means 46. The two holding portions 57 are each formed in a square shape and are connected by a corner portion 59. That is, the carriage side portion 55 is formed in a step shape. The pair of carriage side portions 55 are located symmetrically so as to sandwich the recording carriage 33 from both sides in the X-axis direction in the plane, and are connected by the carriage connecting portion 56 on the downstream side in the Y-axis direction. In addition, the carriage connecting portion 56 is also formed in a square shape and holds the main curing means 43. Therefore, the first recording unit 31 and the second recording unit 32 mounted on the recording carriage 33 and the main curing unit 43 mounted on the photocuring carriage 44 are aligned at the center in the X-axis direction in the Y-axis direction. doing. That is, the first recording unit 31, the second recording unit 32, and the main curing unit 43 are arranged on the same center line in order from the upstream side in the Y-axis direction. Therefore, the carriage device 2 having a good weight balance in the X-axis direction can be configured, and the carriage device 2 can be reciprocated in the X-axis direction with the shortest distance with respect to the width of the recording medium W. As a result, the carriage device 2 can be stably moved in the X-axis direction, and an increase in size of the carriage device 2 can be suppressed.

  Further, a large amount of mist (mist ink) generated when ink is ejected from the recording head 30 is generated from the first recording unit 31 on which more recording heads 30 are mounted. However, in the present embodiment, the main curing unit 43 is provided at a position away from the first recording unit 31 with the second recording unit 32 interposed therebetween. That is, the main curing means 43 is provided at a position away from the generation source where a lot of mist is generated and further at a position away in the Y-axis direction. Therefore, the risk that mist adheres to the main curing means 43 can be reduced. As a result, a decrease in the light emission performance (irradiance) of the main curing unit 43 can be appropriately prevented, and the ink on the recording medium W can be reliably main cured, thereby effectively preventing drawing defects due to uncured ink. be able to. Since the second recording unit 32 has few mist generation sources (single second recording head 32a), the possibility that the mist adheres to the main curing unit 43 located downstream in the Y-axis direction is low. .

  Further, in each holding portion 57, a rib 58 that stands perpendicular to the holding portion 57 is provided on a side (surface) facing the recording carriage 33 (see FIG. 3). The rib 58 increases the structural strength of the photocuring carriage 44 and blocks heat exhausted by the cooling unit 52 of the first semi-curing unit 45 or the second semi-curing unit 46 mounted on each holding unit 57. Acts as a barrier. As a result, the performance of each recording head 30 (each first colored recording head 31a, first colorless recording head 31b, and second recording head 32a), each first semi-curing means 45, and each second semi-curing means 46 is deteriorated by heat. Can be effectively prevented.

  The photocuring carriage 44 is disposed outside the recording carriage 33 with a predetermined gap, and sides (surfaces) where the photocuring carriage 44 and the recording carriage 33 face each other are formed in a complementary manner. ing. In other words, the photocuring carriage 44 is formed in a “V” -shaped stepped shape so as to cover the recording carriage 33 from the downstream side in the Y-axis direction. Reference numeral 44 denotes a triangular shape arranged on one side so as to follow the carriage base 23 (or the first guide shaft 13) (see FIGS. 1 and 2). Thus, since the recording carriage 33 and the photocuring carriage 44 are physically separated without contacting each other, the first semi-curing portion 41 and the second semi-curved portion mounted on the photocuring carriage 44 are disposed. The heat generated from the curing unit 42 and the main curing unit 43 does not propagate to the recording carriage 33 (and each recording head 30). Therefore, it is possible to prevent changes in the ejection amount of each ink, distortion of the recording carriage 33, and the like due to the influence of heat. As a result, problems such as displacement of the landing positions of the respective inks on the recording medium W can be prevented, and highly accurate ink ejection can be performed.

  Further, in the photocuring carriage 44 (carriage side portion 55), since the holding portion 57 and the holding portion 57 are connected by the corner portion 59, the heat transfer area between the holding portions 57 is very small. The propagation of heat between the holding parts 57 can also be suppressed. Thereby, since the thermal influence between the 1st semi-hardening part 41, the 2nd semi-hardening part 42, and the main hardening means 43 can be excluded, the light emission performance of each light hardening means does not fall. Therefore, the ink is cured well and the image drawing quality can be maintained well.

  As shown in FIGS. 2 and 5, the carriage base 23 is a resin member, and a shaft engaging portion 61 that is slidably engaged with the first guide shaft 13 and a timing belt 16 c are sandwiched and fixed. And a cantilever support mechanism 63 that cantilever-supports the head unit 21.

  The shaft engaging portion 61 is recessed in a substantially circular shape in a shape complementary to the first guide shaft 13 (semicircular shaft), and slidably engages with the first guide shaft 13 so as to cover the first guide shaft 13 from above. (See FIG. 2 (b)). Further, the belt fixing portion 62 protrudes on the upstream side in the Y-axis direction at the center in the X-axis direction of the carriage base 23, and holds the timing belt 16c (see FIG. 1A). Then, the carriage device 2 reciprocates in the X-axis direction by being pulled by the timing belt 16 c by driving the servo motor 15.

  As shown in FIG. 5, the cantilever support mechanism 63 supports the head unit 21 in a cantilever manner on the downstream side in the Y-axis direction. The cantilever support mechanism 63 includes a pair of pulling springs 64 that pulls the head unit 21 upward, a pair of first pulling springs 65 and a pair of second pulling springs 66 that pull the head unit 21 toward the carriage base 23, have.

  The pair of pulling springs 64 are respectively engaged with hooks provided at both ends of the first head holding portion 37 in the X-axis direction, and the other ends thereof are convex portions protruding from both ends of the carriage base 23 in the X-axis direction. Each is engaged. The pair of first pulling springs 65 engage one end with hooks provided at the upper ends of both ends of the upright portion 39 in the X-axis direction, and the other ends on the upper sides of both sides in the X-axis direction of the carriage base 23. Are respectively engaged with hooks provided on the. Similarly, one pair of the second pulling springs 66 engages with hooks provided at the lower ends of both ends of the upright portion 39 in the X-axis direction, and the other ends of both sides of the carriage base 23 in the X-axis direction. Each hook is engaged with a hook provided on the lower side.

  The head unit 21 is pulled up by a pair of pulling springs 64 and is pressed (pressed down) by a head gap adjusting means 26 (details will be described later). The head unit 21 is attracted to the upstream side in the Y-axis direction by a pair of first attracting springs 65 and a pair of second attracting springs 66, and parallelism adjusting means 27 (details will be described later). Is pressed by. Thus, the head unit 21 is supported on the carriage base 23 in a cantilever state. An X-axis pulling spring 67 that adjusts the position of the head unit 21 (recording carriage 33) in the X-axis direction is provided below the pulling spring 64 on the left side in FIG.

  As shown in FIG. 2, the support frame 24 has a pair of beam members 71 connected at one end to the upper end surface of the carriage base 23 and extending downstream in the Y-axis direction, and the upper surfaces of the beam members 71. And a wall member 73 suspended from the other end of the pair of beam members 71. In addition, a pair of braces 74 are connected to the upper surfaces of the beam members 71 and the wall member 73 to increase the strength of the support frame 24 as a structure. On the downstream surface of the wall member 73 in the Y-axis direction, a plurality (five) of rollers 75 that are in rolling contact with the second guide shaft 14 are arranged at equal intervals in the X-axis direction and are rotatably supported in a cantilever manner. Has been. In addition, the beam member 71, the girder member 72, and the bracing 74 are comprised with the channel material made from an aluminum alloy, and the wall member 73 is comprised with resin. Further, the number of the beam members 71, the girder members 72, and the bracings 74 is arbitrary.

  The plurality of (four) column members 25 have one end connected to both ends of the beam member 72 and a slightly downstream side from the center in the Y-axis direction of each beam member 71, and the other end extending downward is photocured. It is connected to the carriage 44. That is, the light curing carriage 44 is suspended from the support frame 24 by the four support members 25. The four strut members 25 are connected to the photocuring carriage 44 in the vicinity of the first semi-curing means 45 and the second semi-curing means 46, respectively. The photocuring carriage 44 is supported by the strong support frame 24 via the four support members 25, and the photocuring carriage 44 is heated by the heat generated by the first semi-curing means 45 and the second semi-curing means 46. 44 can be effectively prevented from being distorted (thermal deformation). Thereby, the flatness (attitude) which set the photocuring unit 22 is maintainable. Although details will be described later, each post member 25 includes an optical gap adjusting means 28. Further, the number of support members 25 is arbitrary.

  As described above, the photocuring unit 22 is supported by the first guide shaft 13 and the second guide shaft 14 so as to be slidable through the carriage base 23 and the support frame 24 (the plurality of support members 25). The head unit 21 and the light curing unit 22 are located between the first guide shaft 13 and the second guide shaft 14 (see FIG. 1). That is, the carriage device 2 is stably supported by the first guide shaft 13 and the second guide shaft 14 with the entire weight dispersed. As a result, the carriage device 2 as a whole can be moved in the X-axis direction while maintaining a stable posture without vibration when the movement is started and stopped.

  Further, since the head unit 21 and the light curing unit 22 are integrated as the carriage device 2 and can be simultaneously moved in the X-axis direction, the image drawing operation and the semi-curing operation (and the main curing operation) are the same. Can be performed continuously during the movement. Thereby, it is possible to draw and cure an image efficiently and in a short time. Further, since the head unit 21 and the photocuring unit 22 can face the entire recording surface F (all areas to be recorded) of the recording medium W by moving the carriage device 2, the head unit 21 and the photocuring unit 22 are photocured. The unit 22 can be configured in a small size, so that the entire carriage device 2 can be reduced in size.

  As shown in FIG. 5, the head gap adjusting means 26 includes an adjustment gear 82 (a reduction gear train made up of planetary gears) connected to an adjustment motor (not shown) via a gear train 81 (see FIG. 1B). A gap adjusting shaft 83 to which rotation is transmitted from the adjusting gear 82 and a pair of eccentric cams 84 connected to the gap adjusting shaft 83 are provided.

  In this gap adjustment, first, when the carriage device 2 moves to the home position H, the drive shaft of the adjustment motor is connected to the gear train 81 and the gear train 81 rotates and engages with the adjustment gear 82. Then, each eccentric cam 84 rotates through a gap adjustment shaft 83 that is rotatably supported by the carriage base 23 by driving the adjustment motor. Each eccentric cam 84 is in contact with the upper end surface of each standing portion 39 of the recording carriage 33 (the first head holding portion 37). For this reason, the recording carriage 33 (head unit 21) is pushed down against each pulling spring 64 of the above-mentioned cantilever support mechanism 63 or pulled up by each pulling spring 64 with the rotation of each eccentric cam 84. Or move up and down. Therefore, the gap between the head unit 21 (each recording head 30) and the recording medium W can be appropriately changed according to the thickness and type of the recording medium W (such as ink permeation or non-penetration). As a result, optimal ink ejection can be performed, and high-precision image drawing can be performed on the recording medium W. The adjustment motor may be omitted so that it can be adjusted manually, or each eccentric cam 84 can be rotated separately so that the pitch angle can be finely adjusted.

  As shown in FIG. 5, the parallelism adjusting means 27 includes an eccentric shaft 85 that is in contact with the upstream side (rear side) of each standing portion 39 in the Y-axis direction. The eccentric shaft 85 is rotatably supported by the carriage base 23. As the eccentric shaft 85 rotates, the recording carriage 33 (head unit 21) moves to each first pulling spring of the cantilever support mechanism 63 described above. 65 and the second pulling springs 66 are pushed out against each other, or pulled by the first pulling springs 65 and the second pulling springs 66 to rotate in the rolling direction. In this way, the head unit 21 (each recording head 30) can be maintained in parallel, and the parallelism for each recording head 30 can be made uniform. As a result, each recording head 30 (each first colored recording head 31a, first colorless recording head 31b, and second recording head 32a) can face the recording medium W in parallel with an appropriate gap. Can be discharged.

  As shown in FIG. 6, the optical gap adjusting means 28 includes two adjusting rotating shafts 87 to which rotation from the geared motor 86 is transmitted, a pair of two pinions 88 connected to the adjusting rotating shaft 87, and A plurality of racks 89 with which the pinions 88 are engaged, and a plurality of guide mechanisms (not shown) that maintain the engaged state between the racks 89 and the pinions 88 and guide the vertical movement (lifting). .

  Each rack 89 is formed on the column member 25, and each adjustment rotary shaft 87 is supported rotatably with respect to the photocuring carriage 44 (see FIG. 6C). In this optical gap adjustment, when the carriage device 2 moves to the home position H, the drive shaft of each geared motor 86 is connected to each adjustment rotary shaft 87. A pair of pinions 88 (see FIG. 6A) arranged in the X-axis direction on the upstream side in the Y-axis direction are moved along the racks 89 by driving a geared motor 86 connected to one end of the adjustment rotating shaft 87. Rotate. The same applies to the pair of pinions 88 arranged in the X-axis direction on the downstream side in the Y-axis direction. In this way, the photocuring carriage 44 moves up and down (up and down) along each rack 89 by the rotation of each pinion 88. For this reason, the gap between the photo-curing unit 22 and the recording medium W can be changed as appropriate according to the thickness and type of the recording medium W, and the optimum depending on the type of ink and the type of recording medium W. The ink droplets on the recording medium W can be appropriately cured by irradiating light of intensity (irradiance). Note that the optical gap adjusting means 28 may be provided on the upper side of each column member 25 (or in the middle in the Z-axis direction). Alternatively, the adjustment rotation shaft 87 may be omitted, and each pinion 88 may be rotated individually. In addition, each strut member 25 may have a nested slide structure, and the inner strut and the outer strut may be screwed together to rotate the screw (lead screw mechanism). The member 25 may be slid as a cylinder / piston structure.

  Next, an image forming method controlled by the control unit 6 of the inkjet recording apparatus 1 according to the present embodiment will be described with reference to FIGS. In the following description, nine colored inks excluding the colorless (CL) ink supplied to the first recording unit 31 are referred to as “first colored ink 91”, and the colorless ink is referred to as “first colorless ink 92”. " Similarly, the colorless ink supplied to the second recording unit 32 is referred to as “second ink 93”. The first colored ink 91 is supplied to the plurality of first colored recording heads 31a of the first recording unit 31, and the first colorless ink 92 is supplied to the first colorless recording head 31b. Further, colorless second ink 93 is supplied to the second recording head 32 a of the second recording unit 32. Further, prior to the image forming operation, the carriage device 2 is positioned at the home position H, and the recording surface F of the recording medium W (the recording surface F of the recording medium W) is adjusted by the head gap adjusting unit 26, the parallelism adjusting unit 27, and the optical gap adjusting unit 28. ) And the parallelism adjustment of the head unit 21 (each recording head 30) and the gap adjustment of the photocuring unit 22 are performed.

  As shown in FIG. 7, in this image forming method, the first colored ink 91 and the first colorless ink 92 are ejected, and the visible image D1 and the portion other than the visible image D1 are embedded on the recording medium W so as to be invisible. Image forming step S1 for forming image D2 and first semi-curing unit 41, image semi-curing that semi-cures first colored ink 91 constituting visible image D1 and first colorless ink 92 constituting non-visible image D2 The coating layer D3 is configured by the step S2, the coating layer forming step S3 that discharges the second ink 93 and forms the coating layer D3 on the visible image D1 and the invisible image D2, and the second semi-cured portion 42. A second semi-curing step S4 for semi-curing the second ink 93; and a main curing step S5 for main-curing the visible image D1, the invisible image D2 and the coat layer D3 by the main curing means 43. . Note that the “visible image forming step” and “invisible image forming step” in the claims are performed simultaneously as “image forming step S1” in the present embodiment. Similarly, the “first colored semi-curing step” and the “first colorless semi-curing step” in the claims are performed simultaneously as the “image semi-curing step S2”.

  In the image forming step S1 (image forming operation), the carriage device 2 is reciprocated in the X-axis direction with respect to the recording medium W transported to the position facing the first recording unit 31, and based on the image data, the first The first colored ink 91 is ejected from the recording unit 31 to form (draw) the visible image D1. Concurrently with this, the first colorless ink 92 is ejected to draw a non-visible image D2 on the portion of the image data where the first colored ink 91 is not ejected, that is, on the background portion of the visible image D1 (FIG. 8). (See (a)). As described above, the recording surface F of the recording medium W on which the visible image D1 and the invisible image D2 are formed is filled with the first colored ink 91 and the first colorless ink 92 (see FIG. 9A). ). Therefore, unevenness due to the presence or absence of ink landing does not occur on the recording medium W. In this embodiment, each head discharges (draws) ink from the head unit 21 during reciprocating movement (forward movement and backward movement), but drawing is performed only during forward movement or backward movement. You may do it.

  In the image semi-curing step S2 (image semi-curing operation), the first colored ink 91 and the first colorless ink 92 landed on the recording medium W in the image forming step S1 while reciprocating the carriage device 2 in the X-axis direction. (Ink droplet) is semi-cured. For example, when the carriage device 2 draws the visible image D1 and the invisible image D2 during the forward movement, the first semi-curing means 45 on the downstream side in the forward movement direction (the right side in FIG. 8) is used to emit ultraviolet rays. Moving forward while irradiating (see FIG. 8B). That is, semi-curing can be performed immediately after the first colored ink 91 and the first colorless ink 92 are ejected. In this case, since the ink droplets on the recording medium W can be semi-cured continuously with the movement for drawing, the visible image D1 and the invisible image D2 can be formed in a short time (drawing and half-printing). Curing).

  In addition, it is possible to perform drawing only during forward movement and to perform semi-curing using the first semi-curing means 45 on the downstream side in the backward movement direction during backward movement. In this case, each ink droplet on the recording medium W takes a long time until it is irradiated with ultraviolet rays, so that the ink droplet is greatly wetted and spreads, resulting in a smooth surface in which unevenness is further suppressed. In this manner, the time until the first colored ink 91 and the first colorless ink 92 are semi-cured can be controlled, and the surface roughness of the visible image D1 and the invisible image D2 can be arbitrarily set. Further, by semi-curing, not only the color mixing of each ink is prevented, but also the size of each ink drop is made uniform, so that the unevenness of the surface of the visible image D1 and the invisible image D2 is suppressed and flattened. Can do. Thereby, a smooth coat layer D3 can be formed in a subsequent step.

  When the image forming step S1 and the image semi-curing step S2 are completed, the portion on which the visible image D1 and the invisible image D2 of the recording medium W are drawn by the medium feeding mechanism 12 reaches the position facing the second recording unit 32 in the Y axis. It is moved downstream in the direction and fixed on the platen 17 again. Then, the subsequent coat layer forming step S3 is performed on the drawn visible image D1 and invisible image D2.

  In the coat layer forming step S3 (coat layer forming operation), the second ink 93 is ejected from the second recording unit 32 while the carriage device 2 is reciprocated in the X-axis direction, and the visible image D1 and the invisible image D2 are generated. A transparent coat layer D3 for protecting and giving gloss is formed (see FIG. 8C). As described above, the recording medium W (recording surface F) is filled with the semi-cured visible image D1 and non-visible image D2, and the recording medium W is not uneven due to ink droplets. As a result, the second ink 93 is ejected on the ground without any irregularities (visible image D1 and invisible image D2), so that the coat layer D3 having no gloss and having good gloss is formed. Can do. Similar to the image forming step S1, the coat layer forming step S3 also discharges the second ink 93 during reciprocating movement (during forward movement and backward movement), but either during forward movement or during backward movement. Only the coat layer forming operation may be performed.

  In the second semi-curing step S4 (coating layer semi-curing operation), as in the image semi-curing step S2, the second semi-curing means 46 is used to form the coat layer while reciprocating the carriage device 2 in the X-axis direction. In step S3, the second ink 93 landed on the visible image D1 and the non-visible image D2 is semi-cured (see FIG. 8D). Accordingly, the second ink 93 can be semi-cured with the coating layer forming operation and continuously or at intervals, and the surface roughness of the coating layer D3 can be adjusted. Note that the visible image D1 (first colored ink 91) and the non-visible image D2 (first colorless ink 92) are semi-cured, so the second ink 93 does not mix.

  Here, in the second semi-curing step S4, semi-curing is performed with an irradiance lower than that in the image semi-curing step S2. That is, the second semi-cured portion 42 irradiates ultraviolet rays having a lower irradiance than the first semi-cured portion 41 by current control. For this reason, each ink droplet of the second ink 93 constituting the coat layer D3 is not cured from the surface to a deep position inside, and is easily spread. Thereby, the coat layer D3 has a smooth surface without unevenness on the visible image D1 and the invisible image D2, and can have more beautiful gloss. Further, by adjusting the irradiance of ultraviolet rays and adjusting the wetting and spreading of the second ink 93, any gloss adjustment such as matte (matte) or glossy (glossy) may be performed. In the present embodiment, the first colorless ink 92 and the second ink 93, which are colorless inks, use the same ink. However, inks having different viscosities, gloss when cured, and the like may be used. Good. In this case, the irradiance of the ultraviolet rays irradiated from the second semi-cured portion 42 is appropriately changed. For example, when the second ink 93 is difficult to cure, the irradiance is set equal to or higher than that of the first semi-cured portion 41.

  When the coating layer forming step S3 and the second semi-curing step S4 are completed, the portion where the visible image D1, the invisible image D2, and the coating layer D3 of the recording medium W are formed by the medium feeding mechanism 12 is transferred to the main curing unit 43. It moves to the downstream side in the Y-axis direction to the position where it faces, and is fixed on the platen 17 again. Then, the subsequent main curing step S5 is performed on the formed visible image D1, invisible image D2, and coat layer D3.

  In the main curing step S5 (main curing operation), the visible image D1, the non-visible image D2, and the coat layer D3 are fully cured by the main curing unit 43 while the carriage device 2 is reciprocated in the X-axis direction (FIG. 8 ( e)). In this case, since the visible image D1, the non-visible image D2, and the coat layer D3 are already semi-cured, the time required for the main curing operation can be shortened. Further, since the visible image D1, the invisible image D2, and the coat layer D3 are completely cured, even if the drawn recording media W are stacked one after another, the drawing result (image) may be lost or ink stains may appear. Absent.

  When the coat layer forming step S3 and the second semi-curing step S4 are performed, the image forming step S1 and the image semi-curing step S2 are performed in parallel on the upstream side in the Y-axis direction (FIG. 9 ( b)). Similarly, when the main curing step S5 is performed, on the upstream side in the Y-axis direction, the coating layer forming step S3 and the second semi-curing step S4, the image forming step S1 and the image semi-curing step S2 are performed in parallel. (See FIG. 9C). That is, in the inkjet recording apparatus 1 of the present embodiment, (1) drawing of the visible image D1 and the invisible image D2 and their semi-curing, (2) formation of the coating layer D3 and its semi-curing, and (3) the visible image D1. The main curing of the invisible image D2 and the coat layer D3 can be performed in parallel and continuously in the same main scan (movement in the X-axis direction). Thereby, the visible image D1, the invisible image D2, and the coat layer D3 can be efficiently formed on the recording medium W.

  Note that the above-described image forming method (the procedure thereof) is an example, and each step may be performed at least when the carriage device 2 moves forward or backward. For example, the image forming step S1, the image semi-curing step S2, and the main curing step S5 may be performed when the carriage device 2 moves forward, and the coat layer forming step S3 and the second semi-curing step S4 may be performed when returning.

  According to the above configuration, the visible image D1 and the invisible image D2 are formed in a semi-cured state so as to fill the recording surface F on the recording medium W. Unevenness due to non-uniform size does not occur. Thereby, the smooth coat layer D3 without an unevenness | corrugation can be formed, and favorable gloss can be given to the formed image (visible image D1 and invisible image D2).

(Second Embodiment)
The curing method of the ultraviolet curable ink can be controlled not only by the irradiance (illuminance) of the received ultraviolet rays but also by the integrated amount of the received ultraviolet rays (time when the ultraviolet rays are received).
Therefore, by making the length of each second semi-curing means 46 in the X-axis direction shorter (smaller) than that of each first semi-curing means 45, ultraviolet rays are applied to the second ink 93 on the recording medium W. The irradiation time may be shortened. That is, by reducing the area of the light irradiation part 51 of each second semi-curing means 46, the integrated amount of ultraviolet rays received by the second ink 93 on the recording medium W is reduced. Thereby, similarly to the first embodiment, the second ink 93 is easily wetted and spread, and a smooth coat layer D3 can be formed.

  1: ink jet recording apparatus, 2: carriage apparatus, 3: moving means, 6: control means, 21: head unit, 22: photocuring unit, 30: recording head, 31: first recording section, 31a: first color recording Head 31b: first colorless recording head 32: second recording unit 32a: second recording head 33: recording carriage 41: first semi-curing unit 42: second semi-curing unit 43: main curing means 44: light curing carriage, 91: first colored ink, 92: first colorless ink, 93: second ink, D1: visible image, D2: invisible image, D3: coat layer, W: recording medium

Claims (8)

An inkjet recording apparatus that forms a desired image on the recording medium by ejecting photocurable ink from the recording unit while moving an inkjet recording unit relative to the recording medium,
A first recording unit that ejects a colored first colored ink and ejects a colorless first colorless ink;
A second recording unit that discharges colorless second ink;
An image semi-light curing portion for semi-curing the first colored ink and the first colorless ink;
A first coat layer semi-light-curing part and a second coat layer semi- light- curing part for semi-curing the second ink;
A main-curing unit that permanently cures the first colored ink, the first colorless ink, and the second ink;
A recording carriage on which the first recording unit and the second recording unit are mounted;
The main curing unit, and the photocuring carriage mounted with the image half photocuring unit, the first coating layer half photocured portion and the second coating layer half photocured sections,
Moving means for integrally moving the recording carriage and the photocuring carriage relative to the recording medium in a main scanning direction and a sub-scanning direction;
A control unit for controlling the first recording unit, the second recording unit, the main curing unit, the image semi-photo curing unit, the first coat layer semi-photo curing unit, and the second coat layer semi-photo curing unit; With
The first recording unit and the second recording unit are arranged side by side in the sub-scanning direction, and are arranged in the center of the recording carriage in the main scanning direction,
The photocuring carriage has a first holding part on which the first coat layer semi-light curing part is mounted and a second holding part on which the second coat layer semi-light curing part is mounted, and the first holding part; The second holding portion is disposed symmetrically with the recording carriage interposed therebetween,
The control unit ejects the first colored ink to form a visible image on the recording medium, and ejects the first colorless ink to fill a portion other than the visible image on the recording medium. An image forming operation for forming a non-visible image;
Image semi-curing operation for semi-curing the first colored ink constituting the visible image and the first colorless ink constituting the non-visible image;
A coat layer forming operation of discharging the second ink to form a coat layer on the visible image and the invisible image;
An ink jet recording apparatus, comprising: a coat layer semi-curing operation for semi-curing the second ink constituting the coat layer.   The inkjet recording apparatus according to claim 1, wherein the control unit performs the semi-curing in the coat layer forming operation at an irradiance lower than that of the image semi-curing operation. The main curing unit is configured to main cure the visible image, the invisible image, and the coat layer,
The ink jet recording apparatus according to claim 1, wherein the control unit controls the main curing unit, and performs the main curing operation after the coat layer semi-curing operation.   The first recording unit includes a plurality of first colored recording heads that eject the first colored inks of a plurality of colors, and a single first colorless recording head that ejects the first colorless ink. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is an ink jet recording apparatus.   5. The ink jet recording apparatus according to claim 1, wherein the second recording unit is disposed downstream of the first recording unit in the sub-scanning direction. 6.   The inkjet recording apparatus according to claim 1, wherein the second recording unit includes a single second recording head that discharges the second ink.   7. The image half-light curing unit includes an image half-light curing unit disposed outside at least one of the first recording units in the main scanning direction. 2. An ink jet recording apparatus according to item 1.   The inkjet recording apparatus according to claim 3, wherein the main curing unit is disposed on the downstream side in the sub-scanning direction with respect to the second recording unit.

Images