JP2017154381A - Image formation device and image formation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively inhibit light from entering into a head.SOLUTION: An image formation device includes: a transport part which transports a recording medium in a first direction; a first head which discharges a photo-curing liquid to a surface of the recording medium; a light radiation part which is disposed at the downstream side of the first head in the first direction and radiates light to the surface of the recording medium; a second head which is disposed at the downstream side of the light radiation part in the first direction and discharges a photo-curing liquid to the surface of the recording medium; and a roller which is rotatably supported between the light radiation part and the second head in the first direction and contacts with the surface of the recording medium.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a technique for curing an optically curable liquid discharged onto a recording medium by light irradiation to form an image composed of the liquid on the recording medium.

  The ink jet recording apparatus described in Patent Document 1 includes a plurality of recording heads arranged in the conveyance direction of the recording medium, and ejects ink that is cured by irradiation of ultraviolet rays from each recording head to the recording medium. In addition, an ultraviolet irradiation device is disposed between the adjacent recording heads, and the ultraviolet irradiation device irradiates the ink ejected onto the recording medium with ultraviolet rays to cure the ink.

JP 2007-203624 A

  In such an image forming apparatus, since the light irradiation unit is disposed adjacent to the head, a part of the light emitted from the light irradiation unit may enter the head and damage the head. Therefore, in Patent Document 1, the incidence of light from the head is suppressed by a light shielding plate. Such a light shielding plate has a certain effect. However, it is necessary to provide a gap between the light shielding plate and the recording medium so that the recording medium can be smoothly conveyed. For this reason, the light passing through the gap may enter the head.

  The present invention has been made in view of the above problems, and an object thereof is to provide a technique capable of effectively suppressing the incidence of light on the head.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects.

  According to a first aspect of the present invention, a transport unit that transports a recording medium in a first direction, a first head that discharges a photocurable liquid onto the surface of the recording medium, and a downstream side of the first head in the first direction. A light irradiating unit that irradiates light on the surface of the recording medium, and a second that is disposed downstream of the light irradiating unit in the first direction and discharges a photocurable liquid to the surface of the recording medium. A head, and a roller that is rotatably supported between the light irradiation unit in the first direction and the second head and that contacts the surface of the recording medium.

  The second aspect of the present invention includes a step of discharging a photocurable liquid from the first head onto the surface of the recording medium conveyed in the first direction, and light disposed downstream of the first head in the first direction. Irradiating the surface of the recording medium with light from the irradiation unit, and discharging a photocurable liquid from a second head disposed downstream of the light irradiation unit in the first direction. A roller disposed between the light irradiation unit and the second head contacts the surface of the recording medium.

  As described above, in the configuration in which the light irradiation unit is provided on the upstream side of the second head in the conveyance direction of the recording medium, a part of the light emitted from the light irradiation unit may enter the second head. Therefore, in the present invention, a roller disposed between the light irradiation unit and the second head contacts the surface of the recording medium. Therefore, the light which goes to a 2nd head among the lights inject | emitted from the light irradiation part can be interrupted | blocked with a roller. In addition, the roller is rotatably supported and is in contact with the recording medium, and the gap between the recording medium and the recording medium can be eliminated without disturbing the conveyance of the recording medium. As a result, the incidence of light on the head can be effectively suppressed.

  The roller diameter may be longer than the gap between the second head and the recording medium. In such a configuration, it is possible to reliably block light from entering the gap between the second head and the recording medium by the roller, and it is possible to more effectively suppress light from entering the head.

  Moreover, you may comprise the diameter of a roller so that it may be longer than the clearance gap between a light irradiation part and a recording medium. In such a configuration, the light that leaks from the gap between the irradiation unit and the recording medium and travels toward the second head can be reliably blocked by the roller, and the incidence of light on the head can be more effectively suppressed. It becomes.

  The second head may include a nozzle row in which nozzles are arranged in a direction orthogonal to the first direction, discharge liquid from the nozzle, and the roller may be longer than the nozzle row. In such a configuration, the incidence of light on the nozzles of the second head can be reliably blocked by the roller. As a result, it is possible to effectively suppress the occurrence of damage such that the liquid adhering to the nozzle is hardened by light irradiation and clogs the nozzle.

  The light irradiation unit may include a light source array in which light sources are arranged in a direction orthogonal to the first direction, irradiate light from the light source, and the roller may be configured to be longer than the light source array. In such a configuration, the light emitted from the light source of the irradiating unit and traveling toward the second head can be reliably blocked by the roller, so that the incidence of light on the head can be more effectively suppressed.

  Further, the distance in the first direction along the recording medium from the roller to the second head may be shorter than the distance in the first direction along the recording medium from the light irradiation unit to the roller. good. By bringing the roller close to the second head in this way, it is possible to more effectively suppress the incidence of light on the second head.

  Moreover, you may comprise so that the direction in which a light irradiation part injects light may incline to the roller side rather than a 1st head. With such a configuration, the amount of light traveling toward the first head after being emitted from the light irradiation unit is suppressed, and the incidence of light from the first head can be effectively suppressed. Moreover, although the light which goes to a 2nd head after inject | emitting from a light irradiation part increases, since these lights are interrupted | blocked by a roller, incidence | injection of the light to a 2nd head can also be suppressed effectively.

  Further, a light shielding plate may be provided between the first head and the light irradiation unit in the first direction so as to be provided with a gap between the recording medium and the recording medium. As a result, the incidence of light on the first head can be suppressed to a certain extent.

  In addition, the roller that contacts the recording medium is supported so as to be movable in the second direction, and a roller support unit that supports the roller so that components in the second direction of the roller's own weight are directed to the recording medium, and the roller's own weight An elastic member that is smaller than the component in the second direction and that gives the roller an elastic force that works in a direction away from the recording medium along the second direction may be provided. Such a configuration can quickly displace the roller according to the foreign matter adhering to the recording medium, and is advantageous in smoothly conveying the recording medium.

  Further, the roller may be configured to follow the recording medium as it is conveyed. Such a configuration is advantageous in smoothly transporting the recording medium.

  Note that not all of the plurality of constituent elements included in each aspect of the present invention described above are essential, and in order to solve part or all of the above-described problems or a part of the effects described in the present specification. Or, in order to achieve all of them, it is possible to change, delete, replace with other new components, or delete some of the limited contents of some components of the plurality of components as appropriate. is there. In order to solve part or all of the above-described problems or to achieve part or all of the effects described in this specification, technical features included in one embodiment of the present invention described above. A part or all of the technical features included in the other aspects of the present invention described above may be combined to form an independent form of the present invention.

1 is a front view illustrating an example of a device configuration of a printer to which the present invention is applied. FIG. 3 is a front view illustrating the arrangement relationship of a light-shielding roller and the like with respect to a recording head and the like. FIG. 3 is a plan view showing a positional relationship of a light shielding roller or the like with respect to a recording head or the like. The front view which shows the arrangement | positioning relationship of the light-shielding roller etc. with respect to the recording head etc. which concern on a modification.

  FIG. 1 is a front view schematically showing an example of a device configuration of a printer to which the present invention is applied. As shown in FIG. 1, in the printer 1, a single web S having both ends wound around a feed shaft 20 and a take-up shaft 40 in a roll shape is stretched along a conveyance path. Printing is received while being conveyed in the conveyance direction Dc from the feeding shaft 20 toward the winding shaft 40. The type of the web S is roughly divided into a paper system and a film system. Specific examples include high-quality paper, cast paper, art paper, coated paper, and the like for paper, and synthetic paper, PET (Polyethylene terephthalate), PP (polypropylene), and the like for film. Schematically, the printer 1 includes a feeding unit 2 (feeding region) for feeding the web S from the feeding shaft 20, a process unit 3 (process region) for recording an image on the web S fed from the feeding unit 2, and a process. A winding unit 4 (winding region) for winding the web S on which the image is recorded in the unit 3 around the winding shaft 40 is provided. In the following description, of both surfaces of the web S, the surface on which an image is recorded is referred to as the front surface, and the opposite surface is referred to as the back surface.

  The feeding unit 2 includes a feeding shaft 20 around which the end of the web S is wound, and a driven roller 21 around which the web S drawn from the feeding shaft 20 is wound. The feeding shaft 20 supports the end of the web S by winding it with the surface of the web S facing outward. Then, the web S wound around the feed shaft 20 is fed to the process unit 3 via the driven roller 21 as the feed shaft 20 rotates clockwise in FIG. Incidentally, the web S is wound around the feeding shaft 20 via a core tube 22 that can be attached to and detached from the feeding shaft 20. Therefore, when the web S of the feeding shaft 20 is used up, it is possible to replace the web S of the feeding shaft 20 by attaching a new core tube 22 around which the roll-shaped web S is wound to the feeding shaft 20. It has become.

  The process unit 3 performs processing by the functional units 5a, 5b, 6a, 6b, and 6c arranged along the outer peripheral surface of the rotating drum 30 while supporting the web S fed from the feeding unit 2 by the rotating drum 30. An image is recorded on the web S as appropriate. In the process unit 3, a front drive roller 31 and a rear drive roller 32 are provided on both sides of the rotary drum 30, and the web S that is transported from the front drive roller 31 to the rear drive roller 32 in the transport direction Dc. Is supported by the rotary drum 30 and receives printing.

  The front driving roller 31 has a plurality of minute protrusions formed by thermal spraying on the outer peripheral surface, and winds the web S fed from the feeding unit 2 from the back side. Then, the front drive roller 31 rotates in the clockwise direction of FIG. 1 to convey the web S fed from the feeding unit 2 to the downstream side in the transport direction Dc. A nip roller 31 n is provided for the front drive roller 31. The nip roller 31n is in contact with the surface of the web S while being urged toward the front drive roller 31 and sandwiches the web S between the front drive roller 31 and the nip roller 31n. Thereby, the frictional force between the front drive roller 31 and the web S is ensured, and the web S can be reliably conveyed by the front drive roller 31.

  The rotary drum 30 is a cylindrical drum having a diameter of, for example, 400 [mm] supported by a support mechanism (not shown) so as to be able to rotate in both the transport direction Dc and the opposite direction. The web S conveyed to the driving roller 32 is wound from the back side. The rotating drum 30 supports the web S from the back side while receiving the frictional force with the web S and rotating in the conveyance direction Dc of the web S. Incidentally, the process unit 3 is provided with driven rollers 33 and 34 for folding the web S on both sides of the winding part around the rotary drum 30. Among these, the driven roller 33 wraps the surface of the web S between the front drive roller 31 and the rotary drum 30 and folds the web S. On the other hand, the driven roller 34 wraps the surface of the web S between the rotating drum 30 and the rear drive roller 32 and folds the web S. In this way, by folding the web S on the upstream and downstream sides in the transport direction Dc with respect to the rotating drum 30, it is possible to secure a long winding portion of the web S around the rotating drum 30.

  The rear driving roller 32 has a plurality of minute protrusions formed by thermal spraying on the outer peripheral surface, and winds the web S conveyed from the rotating drum 30 via the driven roller 34 from the back surface side. Then, the rear driving roller 32 rotates clockwise in FIG. 1 to convey the web S to the winding unit 4. A nip roller 32n is provided for the rear drive roller 32. The nip roller 32 n is in contact with the surface of the web S while being biased toward the rear drive roller 32, and sandwiches the web S with the rear drive roller 32. Thereby, the frictional force between the rear drive roller 32 and the web S is ensured, and the web S can be reliably conveyed by the rear drive roller 32.

  Thus, the web S conveyed from the front drive roller 31 to the rear drive roller 32 is supported on the outer peripheral surface of the rotary drum 30. In the process unit 3, a plurality of recording heads 5 a corresponding to different colors are provided in order to record a color image on the surface of the web S supported by the rotary drum 30. Specifically, four recording heads 5a corresponding to yellow, cyan, magenta, and black are arranged in the transport direction Dc in this color order. Each recording head 5a is opposed to the surface of the web S wound around the rotary drum 30 with a slight clearance, and ejects the corresponding color ink (colored ink) from the nozzles by an ink jet method. Then, each recording head 5a ejects ink onto the web S conveyed in the conveyance direction Dc, whereby a color image is formed on the surface of the web S.

  Incidentally, as the ink, UV (ultraviolet) ink (photo-curable ink) that is cured by irradiating ultraviolet rays (light) is used. Therefore, in the process unit 3, UV irradiators 6 a and 6 b are provided to cure the ink and fix it on the web S. The ink curing is performed in two stages, temporary curing and main curing. A temporary curing UV irradiator 6a is disposed between each of the plurality of recording heads 5a. That is, the UV irradiator 6a irradiates the ultraviolet rays having a weak irradiation intensity to cure (temporarily cure) the ink so that the way in which the ink wets and spreads is sufficiently slower than the case where the ultraviolet rays are not irradiated. It does not cure the ink. On the other hand, a UV irradiator 6b for main curing is provided on the downstream side in the transport direction Dc with respect to the plurality of recording heads 5a. That is, the UV irradiator 6b is cured (mainly cured) by irradiating ultraviolet rays having a stronger irradiation intensity than the UV irradiator 6a so that the wetting and spreading of the ink is stopped.

  In this way, the UV irradiator 6a disposed between each of the plurality of recording heads 5a temporarily cures the colored ink ejected to the web S from the recording head 5a on the upstream side in the transport direction Dc. Accordingly, the ink ejected from the one recording head 5a onto the web S is temporarily cured before reaching the recording head 5a adjacent to the one recording head 5a on the downstream side in the transport direction Dc. As a result, the occurrence of color mixing such as mixing of colored inks of different colors is suppressed. In a state where the color mixture is suppressed in this way, the plurality of recording heads 5 a ejects colored inks of different colors to form a color image on the web S. Furthermore, a UV irradiator 6b for main curing is provided on the downstream side in the transport direction Dc from the plurality of recording heads 5a. Therefore, the color image formed by the plurality of recording heads 5a is permanently cured by the UV irradiator 6b and fixed on the web S.

  Furthermore, a recording head 5b is provided downstream of the UV irradiator 6b in the transport direction Dc. The recording head 5b is opposed to the surface of the web S wound around the rotary drum 30 with a slight clearance, and discharges transparent UV ink from the nozzles onto the surface of the web S by an inkjet method. That is, the transparent ink is further ejected with respect to the color image formed by the recording heads 5a for four colors. The transparent ink is ejected over the entire surface of the color image, and gives the color image a texture such as a glossy feeling or a matte feeling. Further, a UV irradiator 6c is provided on the downstream side in the transport direction Dc with respect to the recording head 5b. The UV irradiator 6c irradiates strong ultraviolet rays to fully cure the transparent ink ejected by the recording head 5b. Thereby, the transparent ink can be fixed on the surface of the web S.

  In the above description, the recording heads 5a and 5b are distinguished from each other, and the UV irradiators 6a, 6b, and 6c are distinguished from each other. In contrast, in the following description, the recording heads 5a and 5b are collectively referred to as the recording head 5 as appropriate, and the UV irradiators 6a, 6b, and 6c are collectively referred to as the UV irradiator 6 as appropriate.

  In the process unit 3 configured as described above, the recording heads 5 and the UV irradiators 6 are alternately arranged in the transport direction Dc. In other words, the UV irradiators 6 are adjacent to the recording heads 5 from the transport direction Dc. . Therefore, the process unit 3 arranges the light shielding plate 7 or the light shielding roller 8 between the recording head 5 and the UV irradiator 6 so that the light emitted from the adjacent UV irradiator 6 enters the recording head 5. It is restrained to do. Details of these will be described later with reference to FIGS.

  As described above, in the process unit 3, ink ejection and curing are appropriately performed on the web S wound around the outer peripheral portion of the rotary drum 30, and a color image coated with the transparent ink is formed. Then, the web S on which the color image is formed is conveyed to the winding unit 4 by the rear drive roller 32.

  The winding unit 4 includes a driven roller 41 that winds the web S from the back side between the winding shaft 40 and the rear drive roller 32 in addition to the winding shaft 40 around which the end of the web S is wound. The winding shaft 40 winds and supports the end of the web S with the surface of the web S facing outward. That is, when the winding shaft 40 rotates clockwise in FIG. 1, the web S conveyed from the rear drive roller 32 is wound around the winding shaft 40 via the driven roller 41. Incidentally, the web S is wound around the winding shaft 40 via a core tube 42 that can be attached to and detached from the winding shaft 40. Therefore, when the web S wound around the winding shaft 40 becomes full, the web S can be removed together with the core tube 42.

  FIG. 2 is a front view schematically showing the arrangement relationship of the light shielding plate and the light shielding roller with respect to the recording head and the UV irradiator, and FIG. 3 schematically shows the arrangement relationship of the light shielding plate and the light shielding roller with respect to the recording head and the UV irradiator. FIG. Although the rotary drum 30 has a cylindrical shape as described above, in each of the drawings, each configuration is shown by being linearly developed in the conveyance direction Dc of the web S.

  As shown in the figure, the recording head 5, the UV irradiator 6, and the recording head 5 are arranged in the transport direction Dc and face the surface of the web S wound around the circumferential surface of the rotary drum 30. The recording head 5 has a plurality of nozzles 51 that are shown by broken lines in FIG. 3, and ejects ink from each nozzle 51. These nozzles 51 are arranged in a matrix, and a plurality of nozzle rows 52 each including a plurality of nozzles 51 arranged in parallel in the width direction Dw (that is, the width direction Dw of the web S) perpendicular to the transport direction Dc. Arranged in the transport direction Dc. Further, the UV irradiator 6 has a plurality of light sources 61 that are transmitted and broken in FIG. 3 and indicated by broken lines, and irradiates light (ultraviolet rays) from each light source 61 configured by LEDs (Light Emitting Diodes). These light sources 61 are arranged in a matrix, and a light source array 62 composed of a plurality of light sources 61 arranged in parallel in the width direction Dw is arranged in a plurality of transport directions Dc. Then, the image formed by the upstream recording head 5 ejecting ink onto the surface of the web S is transported toward the UV irradiator 6 in the transport direction Dc, and the UV irradiator 6 irradiates light. This image is cured. The image thus cured is transported toward the downstream recording head 5 in the transport direction Dc, and the downstream recording head 5 ejects ink toward the image to further overlap the images.

  A light shielding plate 7 is disposed between the upstream recording head 5 and the UV irradiator 6 in parallel to the width direction Dw. A gap Δ7 is provided between the surface of the web S and the light shielding plate 7. Accordingly, it is possible to prevent the image from being disturbed by the light shielding plate 7 coming into contact with the image formed on the surface of the web S by the upstream recording head 5. A gap Δ 7 between the surface of the web S and the light shielding plate 7 is narrower than a gap Δ 5 between the surface of the web S and the recording head 5 and a gap Δ 6 between the surface of the web S and the UV irradiator 6. In the width direction Dw, the width W7 of the light shielding plate 7 is wider than the width W52 of the nozzle row 52 and the width W62 of the light source row 62, and the nozzle row 52 and the light source row 62 are respectively located inside the light shielding plate 7.

  Further, between the UV irradiator 6 and the downstream recording head 5, a light shielding roller 8 having a gap Δ5 and a diameter R larger than the gap Δ6 is arranged in parallel to the width direction Dw. The light shielding roller 8 is formed of, for example, metal, alloy steel such as stainless steel, rubber, synthetic resin, or the like. The light shielding roller 8 comes into contact with the web S on its peripheral surface, and is driven to rotate as the web S is transported in the transport direction Dc. At this time, the image of the surface of the web S that is in contact with the light shielding roller 8 has been temporarily cured by light irradiation from the UV irradiator 6 disposed on the upstream side, and therefore the image is disturbed by the contact with the light shielding roller 8. There is no.

  In the width direction Dw, the width W8 of the light shielding roller 8 is wider than the width W52 of the nozzle row 52 and the width W62 of the light source row 62, and the nozzle row 52 and the light source row 62 are respectively located inside the light shielding roller 8. The light shielding roller 8 is disposed closer to the recording head 5 on the downstream side of the UV irradiator 6 in the transport direction Dc. That is, the distance in the conveyance direction Dc along the web S from the light shielding roller 8 to the downstream recording head 5 is larger than the distance La in the conveyance direction Dc along the web S from the UV irradiator 6 to the light shielding roller 8. Lb is shorter. Here, the distance La is an image obtained by projecting a plurality of light sources 61 onto the surface of the web S in the light emission direction (in other words, the optical axis direction of the light source 61), and the light shielding roller 8 on the surface of the web S. It can be determined as an interval in the conveyance direction Dc between the contact portion 81 and the contact portion 81 in contact. The distance Lb is defined between the contact portion 81 and the image projected on the surface of the web S from the plurality of nozzles 51 in the respective ink ejection directions (in other words, the center line direction of the nozzles 51). It can be obtained as an interval in the transport direction Dc.

  Further, a roller support mechanism 9 that supports the light shielding roller 8 is provided. The roller support mechanism 9 includes a rotation shaft 91 that supports the light-shielding roller 8 and a support frame 92 that supports the rotation shaft 91 so as to be slidable in the sliding direction Ds. The rotation shafts 91 are provided at both ends of the light shielding roller 8, and the light shielding rollers 8 can rotate with respect to the rotation shafts 91. The support frame 92 is an annular member having a long hole 921 extending in the sliding direction Ds, and is provided for each rotating shaft 91. At this time, the support frame 92 is provided so that the slide direction Ds intersects the horizontal direction, and the lower end of the support frame 92 faces the web S side. Each rotating shaft 91 is fitted in the long hole 921 of the corresponding support frame 92 and can slide in the sliding direction Ds with the light shielding roller 8. At this time, since the slide direction Ds intersects the horizontal direction, the light-shielding roller 8 approaches the lower end side of the support frame 92 and contacts the web S by its own weight. Thus, the light-shielding roller 8 is in contact with the web S while being supported so as to be rotatable and displaceable in the sliding direction Ds. In this example, the slide direction Ds is parallel to the normal direction of the web S in the contact portion 81, in other words, parallel to the radial direction of the rotary drum 30.

  Further, the roller support mechanism 9 has a tension spring 93 that gives elastic force to the light shielding roller 8 with respect to both ends of the light shielding roller 8. That is, at each of both ends of the light shielding roller 8, one end of the tension spring 93 is attached to the rotating shaft 91 and the other end of the tension spring 93 is attached to the upper end of the support frame 92. The tension spring 93 provides the light shielding roller 8 with an elastic force that works toward the side away from the web S along the sliding direction Ds. At this time, the elastic force acting on the light shielding roller 8 is smaller than the component in the sliding direction Ds of its own weight (that is, gravity acting on the light shielding roller 8), and the resultant force of the gravity acting on the light shielding roller 8 and the elastic force is The force is directed toward the web S along the sliding direction Ds. Therefore, the light-shielding roller 8 contacts the web S with a force (combined force) weaker than its own weight.

  As described above, in this embodiment, the light shielding roller 8 disposed between the UV irradiator 6 and the recording head 5 contacts the surface of the web S. Therefore, the light directed to the recording head 5 among the light emitted from the UV irradiator 6 can be blocked by the light blocking roller 8. In addition, the light-shielding roller 8 is in contact with the web S in a state where the light-shielding roller 8 is rotatably supported, and a gap between the web S and the web S can be eliminated without obstructing the conveyance of the web S. As a result, the incidence of light on the recording head 5 can be effectively suppressed.

  Further, the diameter R of the light shielding roller 8 is longer than the gap Δ5 between the recording head 5 and the web S. With such a configuration, it is possible to reliably block light from entering the gap Δ5 between the recording head 5 and the web S by the light-shielding roller 8, and it is possible to more effectively suppress light from entering the recording head 5. It becomes.

  Further, the diameter R of the light shielding roller 8 is longer than the gap Δ6 between the UV irradiator 6 and the web S. In such a configuration, the light that leaks from the gap Δ6 between the UV irradiator 6 and the web S and travels toward the recording head 5 can be reliably blocked by the light-shielding roller 8, and the light incident on the recording head 5 is more effective. Can be suppressed.

  The light blocking roller 8 is longer than the nozzle row 52 of the recording head 5. With this configuration, the light incident on the nozzles 51 of the recording head 5 can be reliably blocked by the light blocking roller 8. As a result, it is possible to effectively suppress the occurrence of damage such that the ink adhering to the nozzle 51 is cured by light irradiation and clogs the nozzle 51.

  Further, the light shielding roller 8 is longer than the light source row 62 of the UV irradiator 6. In such a configuration, the light emitted from the light source 61 of the UV irradiator 6 and traveling toward the recording head 5 can be reliably blocked by the light-shielding roller 8, and the light incident on the recording head 5 can be more effectively suppressed. It becomes possible.

  Further, the distance Lb in the transport direction Dc along the web S from the light shielding roller 8 to the recording head 5 is shorter than the distance La in the transport direction Dc along the web S from the UV irradiator 6 to the light shielding roller 8. . Thus, by making the light-shielding roller 8 close to the recording head 5, it is possible to more effectively suppress the incidence of light on the recording head 5.

  Further, between the recording head 5 and the UV irradiator 6 in the transport direction Dc, a light shielding plate 7 is disposed which is disposed with a gap Δ7 between the web S. Thereby, the incidence of light on the recording head 5 can be suppressed to a certain extent.

  Further, the support frame 92 brings the light shielding roller 8 into contact with the web S while supporting the light shielding roller 8 movably in the sliding direction Ds so that the component of the light shielding roller 8 in its own weight in the sliding direction Ds is directed to the web S. . Then, the tension spring 93 gives the light blocking roller 8 an elastic force that is smaller than the component of the light blocking roller 8 in its own weight in the sliding direction Ds and works away from the web S along the sliding direction Ds. Such a configuration can quickly displace the light-shielding roller 8 according to the foreign matter attached to the web S, and is advantageous in smoothly transporting the web S.

  Further, the light shielding roller 8 is driven as the web S is conveyed. Such a configuration is advantageous in smoothly transporting the web S.

  Thus, in the present embodiment, the printer 1 corresponds to an example of the “image forming apparatus” of the present invention, and the front driving roller 31 and the rear driving roller 32 cooperate with each other as an example of the “conveying unit” of the present invention. The web S corresponds to an example of the “recording medium” of the present invention, the transport direction Dc corresponds to an example of the “first direction” of the present invention, and the two recording heads 5 of FIGS. Of these, the recording head 5 on the upstream side in the transport direction Dc corresponds to an example of the “first head” in the present invention, and the recording head 5 on the downstream side in the transport direction Dc corresponds to an example of the “second head” in the present invention. The UV irradiator 6 corresponds to an example of the “light irradiation unit” of the present invention, the light shielding roller 8 corresponds to an example of the “roller” of the present invention, and the nozzle 51 corresponds to an example of the “nozzle” of the present invention. The light source 61 corresponds to an example of the “light source” of the present invention, and the light shielding plate 7 of the present invention The rotating shaft 91 and the support frame 92 cooperate to function as an example of the “roller support portion” of the present invention, and the tension spring 93 corresponds to an example of the “elastic member” of the present invention. To do.

  The present invention is not limited to the above-described embodiment, and various modifications can be made to the above-described one without departing from the spirit of the present invention. For example, the recording head 5, the light shielding plate 7, the UV irradiator 6, the light shielding roller 8 and the recording head 5 arranged in the transport direction Dc are arranged at intervals, the size of the light shielding roller 8, the size of the light shielding plate 7, or the gaps Δ5 and Δ6, The magnitude relationship of Δ7 can be changed as appropriate.

  Further, the specific mechanism for supporting the light shielding roller 8 may be appropriately changed, and the tension spring 93 is not necessarily provided. Further, although the light shielding roller 8 is driven to carry the web S, the rotation of the light shielding roller 8 may slightly slip with respect to the web S conveyance.

  Various changes can be made to the specific configurations of the recording head 5 and the UV irradiator 6. Therefore, for example, as proposed in Japanese Patent Application Laid-Open No. 2014-195889, the direction in which the UV irradiator 6 emits light may be inclined with respect to the conveyance direction Dc of the web S in front view. At this time, various specific configurations for tilting the light emission direction are conceivable. For example, the light source 61 has a virtual tangent to the web S at the intersection of the optical axis of the light source 61 and the web S in front view. The UV irradiator 6 can be configured such that the optical axis is inclined.

  FIG. 4 is a front view schematically showing the arrangement relationship of the light shielding plate and the light shielding roller with respect to the recording head and the UV irradiator according to the modification. The notation in FIG. 4 is the same as that in FIG. In the modification of FIG. 4, the light emitting direction of the UV irradiator 6 is inclined toward the recording head 5 on the downstream side of the upstream recording head 5 in the transport direction Dc, that is, on the optical axis of the light source 61. The UV irradiator 6 is configured so that the light Lo that travels along the head is directed toward the recording head 5 on the downstream side of the recording head 5 on the upstream side. In such a configuration, the amount of light that is emitted from the UV irradiator 6 and then travels toward the upstream recording head 5 is suppressed, and the incidence of light on the upstream recording head 5 can be effectively suppressed. In addition, although the amount of light directed to the downstream recording head 5 after being emitted from the UV irradiator 6 increases, the light is blocked by the light-shielding roller 8, so that the incidence of light on the downstream recording head 5 is also effective. Can be suppressed.

  In the above embodiment, the web S is supported by the cylindrical rotary drum 30. However, the shape of the member that supports the web S is not limited to this. For example, the web S may be supported by a flat surface.

  DESCRIPTION OF SYMBOLS 1 ... Printer, 30 ... Rotary drum, 31 ... Front drive roller, 32 ... Rear drive roller, 5 ... Recording head, (DELTA) 5 ... Gap, 6 ... UV irradiator, [Delta] 6 ... Gap, 7 ... Light-shielding plate, [Delta] 7 ... Gap, R ... diameter of light shielding roller, 8 ... light shielding roller, 81 ... contact portion, 9 ... roller support mechanism, 91 ... rotating shaft, 92 ... support frame, 921 ... long hole, 93 ... tension spring, S ... web, Dc ... transport direction , Ds ... slide direction

Claims (11)

A transport unit for transporting the recording medium in the first direction;
A first head for discharging a photocurable liquid onto the surface of the recording medium;
A light irradiator disposed on the downstream side of the first head in the first direction to irradiate light on the surface of the recording medium;
A second head that is disposed downstream of the light irradiation unit in the first direction and that discharges a photocurable liquid onto the surface of the recording medium;
An image forming apparatus comprising: a roller that is rotatably supported between the light irradiation unit and the second head in the first direction and that contacts a surface of the recording medium.   The image forming apparatus according to claim 1, wherein a diameter of the roller is longer than a gap between the second head and the recording medium.   The image forming apparatus according to claim 1, wherein a diameter of the roller is longer than a gap between the light irradiation unit and the recording medium. The second head has a nozzle row in which nozzles are arranged in a direction orthogonal to the first direction, and discharges liquid from the nozzles.
The image forming apparatus according to claim 1, wherein the roller is longer than the nozzle row. The light irradiation unit includes a light source array in which light sources are arranged in a direction orthogonal to the first direction, and irradiates light from the light source.
The image forming apparatus according to claim 1, wherein the roller is longer than the light source row.   The distance from the roller to the second head in the first direction along the recording medium is shorter than the distance from the light irradiation unit to the roller in the first direction along the recording medium. Item 6. The image forming apparatus according to any one of Items 1 to 5.   The image forming apparatus according to claim 1, wherein a direction in which the light irradiation unit emits light is inclined toward the roller with respect to the first head.   8. The light shielding plate according to claim 1, further comprising: a light shielding plate disposed between the first head and the light irradiation unit in the first direction with a gap between the recording medium and the recording medium. Image forming apparatus. A roller support unit that supports the roller in contact with the recording medium so as to be movable in a second direction, and supports the roller such that a component of the weight of the roller in the second direction is directed to the recording medium;
9. The elastic member according to claim 1, further comprising: an elastic member that is smaller than a component of the weight of the roller in the second direction and that exerts an elastic force acting on the roller in a direction away from the recording medium along the second direction. The image forming apparatus according to one item.   The image forming apparatus according to claim 1, wherein the roller is driven as the recording medium is conveyed. Discharging a photocurable liquid from the first head onto the surface of the recording medium conveyed in the first direction;
Irradiating the surface of the recording medium with light from a light irradiator disposed downstream of the first head in the first direction;
A step of discharging a photocurable liquid from a second head disposed on the downstream side in the first direction of the light irradiation unit,
An image forming method in which a roller disposed between the light irradiation unit and the second head in the first direction contacts the surface of the recording medium.

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