JP2012020481A - Image recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image recording apparatus for suppressing the dirt of a curing light source and the optical system of the curing light source caused by the adhesion of the generated ink mist and for preventing the light quantity loss of UV light with which a recording medium is irradiated, in an inkjet image recording apparatus using a light curing-type ink.SOLUTION: The image recording apparatus 1 includes a light irradiation part for curing 5 in which a light emitting element 14 and a condenser lens 15 are stored in a housing part 11 for shielding all but an opening that is irradiated with light, to position a conjugate image in front of the incident side of the opening, so that suspended matter including ink mist is suppressed from entering the housing part 11 and the entered ink mist is made to pass through the conjugate image or an optical path near the conjugate image, to cure the ink mist and reduce fixability.

Description

  The present invention relates to an image recording apparatus that forms a fixed image by irradiating light or the like to ink landed on a recording medium and curing the ink.

  In general, an ink jet technique for recording various characters and images by landing ink droplets on a recording medium can be realized with a relatively simple structure, and is used in various fields. As a recording medium, not only recording paper but also a medium made of a material such as resin, metal, and glass is used, and continuous and large-scale image recording is possible.

  As an ink material applied to the above-described various recording media, there is a photocuring type. The photo-curing type ink cures when the ink layer that has landed is irradiated with ultraviolet light even on a recording medium that does not absorb ink, so that an image can be fixed on the recording medium. That is, the photo-curing type ink can be applied to a medium made of various materials and shapes because restrictions required for the recording medium are reduced.

  Also, recording is possible for molded parts and other media having irregular shapes. Furthermore, since it is a photocuring type, there are few problems, such as an irritating odor, compared with the curing reaction using a volatile solvent. Due to these advantages, in recent years, ink jet printer technology using photo-curing type ink has attracted attention.

Japanese Patent No. 3535713

  However, in the conventional ink jet printer technology, when continuous and large-scale recording is performed, floating of minute ink particles generated in addition to ink landed from the recording head, that is, so-called ink mist occurs. The problem caused by this ink mist is, for example, in Japanese Patent Application Laid-Open No. H11-260707, when ultraviolet curable ink (hereinafter referred to as UV ink) is adopted, curing is caused by irradiation with ultraviolet light (hereinafter referred to as UV light). Up to this point, it is pointed out that since the ink remains in a liquid state, the generated ink mist floats and moves inside the device while it is in a liquid state, and may adhere to components and contaminate the inside of the device. ing.

  In particular, the curing light source and an optical system including the curing light source (including a reflection mirror and a condensing lens) are arranged downstream of the recording head in the conveyance direction of the recording medium. Accordingly, when the generated ink mist is caused to flow downstream as the recording medium is conveyed, it adheres to the curing light source and the optical system including the ink and causes ink stains.

  If the optical system becomes dirty, the intensity of the UV light reaching the recording medium will be weakened and the ink will not be sufficiently cured, causing not only a reduction in image quality but also a large amount of landed ink such as a solid image. In this case, since the liquid ink is discharged in a state where a part of the ink remains, it adheres to the transport mechanism and the discharge mechanism, and the subsequent recording medium is stained.

The occurrence of these problems is more noticeable when the number of recording heads and nozzles provided in the apparatus is large, or when the number of ink ejections per unit time is large.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image recording apparatus that suppresses a stain on a curing light source and its optical system due to adhesion of generated ink mist and prevents a loss of light amount of UV light irradiated on a recording medium. To do.

  In order to achieve the above object, an embodiment according to the present invention promotes image fixing by irradiating light to an image recording unit that records an image on a recording medium and an image recorded on the recording medium. In the image recording apparatus having a light irradiation unit, the light irradiation unit includes a light source that emits light, a condensing member that focuses light emitted from the light source, and a light condensing member that surrounds the light source and the condensing member. And a housing formed with an opening through which the light emitted from the light collecting member passes so as to face the recording medium surface, and the light collecting member focuses the light Provided is an image recording apparatus which is held inside the casing so as to form a conjugate image (condensing point) inward of the opening tip of the casing.

  According to the present invention, it is possible to provide an image recording apparatus that suppresses the stain on the curing light source and its optical system due to the generated ink mist adhering and prevents the loss of the amount of UV light irradiated to the recording medium. .

FIG. 1 is a diagram showing a conceptual configuration of an image recording apparatus equipped with a UV light irradiation apparatus according to the first embodiment. FIG. 2 is a conceptual diagram for explaining generation and floating of ink mist. FIG. 3 is a diagram illustrating an external configuration of the housing portion of the UV light irradiation unit as viewed from obliquely above. FIG. 4 is a diagram illustrating an external configuration of the housing portion of the UV light irradiation unit as viewed from obliquely below on the recording medium side. FIG. 5 is a diagram for explaining ink mist entering the housing. FIG. 6 is a diagram for explaining the ink mist that enters the housing portion when the UV light is irradiated. FIG. 7 is a diagram for explaining the floating direction of the ink mist that has entered the housing. FIG. 8 is a cross-sectional view showing a conceptual configuration of the UV light irradiation unit of the second embodiment. FIG. 9 is a diagram illustrating an external configuration of a UV light irradiation unit viewed from the UV light irradiation side. FIG. 10 is a diagram illustrating an irradiation state in which UV light is irradiated. FIG. 11 is a cross-sectional view showing a conceptual configuration of a UV light irradiation unit in the third embodiment. FIG. 12 is a cross-sectional view showing a conceptual configuration of a UV light irradiation unit according to the fourth embodiment. FIG. 13 is a cross-sectional view illustrating a conceptual configuration of a UV light irradiation unit according to a modification of the fourth embodiment. FIG. 14 is a diagram illustrating the position of the conjugate image (condensing point) in the irradiation light as the first example. FIG. 15 is a diagram of the position of the conjugate image of the first example as viewed from below the opening. FIG. 16 is a diagram illustrating a state in which the position of the conjugate image is set in the opening. FIG. 17 is a diagram illustrating an example in which the position of the conjugate image is set in front of the opening and the opening is formed in a wide tapered shape.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
An image recording apparatus according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a conceptual configuration of an image recording apparatus equipped with a UV light irradiation apparatus, for example, an ultraviolet curable ink jet printer. In the present embodiment and the embodiments described below, ink that is cured by UV light is used, and thus UV light is described as an example of light to be irradiated. However, in practice, light is used. Belongs to electromagnetic waves and includes not only UV light but also visible light and infrared light.

  The image recording apparatus 1 according to the present embodiment includes a wound long recording medium 3, a transport mechanism 7 that transports the recording medium 3, a platen 4 that transports the fed recording medium 3 flatly, and a platen An image recording unit 2 that ejects UV ink droplets 9 onto the recording medium 3 on the upper side, a UV light irradiation unit 5 that irradiates UV light that has landed on the recording medium 3, and a recording medium 3 on which an image is recorded. The processing storage unit 6 is cut and stored by the cutting unit 16 and the control unit 10 controls the image processing and the entire apparatus.

  An external device 18 such as a personal computer is connected to the control unit 10 directly or via a network, and image data, recording conditions, and the like are input. Although not shown, the image recording apparatus according to the present embodiment drives an input operation unit including a keyboard and a touch panel, a display panel that displays recorded images and recording conditions, and other mechanisms. Drive sources such as motors and actuators.

  Among these components, the control unit 10 is not shown, but includes an input / output interface unit, a calculation processing unit including a CPU, and a memory for storing an image processing control program, input image data, and recording conditions thereof. Part. The control unit 10 controls the entire apparatus according to an instruction from the external device 18 or the input operation unit.

  In the present embodiment, the recording medium (moving medium) 3 is an example of a roll paper form, but is not limited thereto, and is a cut sheet by changing the medium supply mechanism or the transport mechanism. Can also be easily applied. Further, the recording medium may be formed of a material described later.

  The transport mechanism 7 fits and holds the recording medium 3 rotatably on a support rotating shaft that can be braked, pulls out the recording medium 3 by a plurality of rollers, transports the platen 4, and stores it in the processing storage unit 6. The image recording unit 2 and the UV light irradiation unit are disposed above the platen 4 and eject a UV ink droplet onto the recording medium 3 conveyed so as to pass over the platen. The ink is cured. In this embodiment, the conveyance speed of the conveyance mechanism 7 is set to, for example, 500 mm / s, and can cope with high-speed recording. Although not shown, the platen 4 has a constant distance (gap) to the recording head in a state where the recording medium 3 to be conveyed is adsorbed by suction by a negative suction pressure by a fan or the like or by electrostatic attraction. To maintain.

  The image recording unit 2 includes an ink jet type recording head 8 formed with a nozzle row in which a plurality of nozzles are arranged in a row, and a recording head driving unit (not shown) that drives the recording head 8 in accordance with instructions from the control unit 10. Z). Although one recording head 8 is typically shown in FIG. 1, the present invention is not limited to this. For recording a color image, four recording heads that discharge at least four colors of UV ink are used. It has a head. That is, ink droplets of four colors of cyan: C, magenta: M, yellow: Y, and black: K are ejected to form an image on a recording medium. The recording head has a performance of 600 dpi, for example.

  The processing storage unit 6 includes a cut unit 16 that cuts the recording medium 3 on which an image is recorded, and a stacker unit that stores the cut recording medium. In the processing storage unit 6, the recording medium 3 is cut into a predetermined size and is stacked and stored on one or more designated trays. The stored recording medium is taken out by the user.

The UV ink employed by the present embodiment will be described.
In this embodiment, for example, a cationic ultraviolet curable ink containing a minute object such as a pigment is used. CI Pigment Blue, CI Pigment Red, CI Pigment Yellow, CI Pigment Black, titanium oxide, or the like can be used as the pigment of the ink. The UV ink is filled in a tank (not shown) in advance, and an appropriate amount is supplied to the recording head 8 as needed. The recording head 8 has a recording width (recording area) wider than the width of the landing medium, corresponds to the UV ink equivalent to that described above, and can perform monochrome and color recording of at least 8 gradations. Further, although the curing energy is about 200 mJ / cm ² or less, radical ink of about 500 mJ / cm ² may be filled and used.

Next, generation of ink mist will be described with reference to FIG.
Usually, the ink mist means that when a desired ink droplet is directly ejected from the recording head 8 toward the recording medium 3, a minute droplet of unintended ink is generated due to the mechanism and is not fixed on the recording medium 3. An unintended minute droplet floating inside the device. There are ink droplets known as so-called satellites and the like, but the ink mist is a droplet having a size approximately equal to or smaller than this satellite. Specifically, the diameter of the ink droplet fixed on the recording medium 3 is usually about several tens of μm, but is about several μm or less in the generation of the droplet.

  The smaller the volume (ink amount) of this ink mist, the greater the force due to air resistance compared to its own weight, so the floating time in the atmosphere in the apparatus becomes longer. In this environment, when an object such as a recording medium moves, the ink mist also moves along with a nearby air current caused by the movement of the object.

  In the present embodiment, the recording head 8 is disposed above the recording medium 3 in the gravity direction. A recording medium is conveyed at a high speed in the direction in which the ink mist generated from the recording head 8 falls, that is, in the vertical direction. An air flow is generated near the surface of the recording medium to be transported, and turbulence may occur particularly when moving at a high speed of about 500 mm / s as described above. For this reason, even if the ink mist is generated from the recording head 8 and is about to fall downward, the ink mist is rolled up in this air current or turbulent flow, and the recording medium 3 and the UV light irradiation unit 5 are disposed in the transport direction. Move downstream.

  Next, the configuration and operation of the UV light irradiation unit 5 will be described in detail with reference to FIGS. FIG. 3 shows an external configuration of the casing of the UV light irradiation unit as viewed from obliquely above. FIG. 4 shows an external configuration of the housing portion of the UV light irradiation unit as viewed from an obliquely lower side on the recording medium side.

  The UV light irradiation unit 5 includes a light emitting element 14 as a light source composed of a plurality of ultraviolet LED elements that emit ultraviolet light, and a collector that collects the emitted ultraviolet light and irradiates the recording medium 3 with UV light. The optical lens 15 constitutes an irradiation optical system. This irradiation optical system is provided in a housing portion 11 (light shielding plate) that shields UV light so that the optical axis of the UV light faces the recording medium 3. Further, a driving circuit board (not shown) for driving the light emitting element 14 is provided in the housing portion 11, and the ultraviolet LED elements are spaced apart on the substrate surface, for example. Has been implemented.

  Furthermore, the configuration of the irradiation optical system in the present embodiment is an example of irradiating UV light with a linear optical axis by the configuration of only the light emitting element 14 and the condenser lens 15 in order to explain as a simple configuration. The arrangement is not limited to this. For example, a well-known optical system member (including a filter or the like) such as a reflecting mirror is disposed on the optical axis of the light emitting element 14 and the condenser lens 15, and UV light is irradiated with a bent optical axis. Good. In other words, in the present embodiment, it is configured to have an irradiation width of UV light having a length equal to or greater than the width of the recording medium, but when there is a restriction on the configuration of the image recording apparatus or temperature management, The configuration may be such that UV light emitted at a separated position is transmitted without disposing the light emitting element 14 immediately after the recording head. Moreover, you may provide the optical instrument which scans and irradiates UV light. Even in such a configuration, since an optical system member such as a lens and an emission window is arranged immediately after the recording head, problems due to ink mist similarly occur.

  By the UV light irradiation unit 5, the UV ink layer that forms an image landed on the recording medium 3 is fixed and cured by being irradiated with UV light. In general, a plurality of UV light irradiation units 5 are arranged so as to be paired with the recording head 3, but only one is shown in FIG. The UV light irradiation unit 5 is provided immediately after the downstream side (conveying direction) of each of the plurality of recording heads 3 for the purpose of fixing ink, and irradiates the downstream side of the recording head group with a large amount of UV light. Further, an arrangement configuration in which an object that finally cures the ink layer may be added.

  The casing 11 is made of a member that blocks UV light, for example, metal. In the configuration shown in FIGS. 3 and 4, a planar light shielding cover portion 11 a that covers both ends in the width direction of the recording medium and extends in the conveyance direction of the recording medium is provided at the lower portion of the housing portion 11. Yes. The cover portion 11a shields UV light, which also acts as harmful light for the eyes, from leaking out as much as possible from the horizontal direction. The cover portion 11a is formed of an aluminum member having a size of about 500 mm × 400 mm and a thickness of about 2 mm.

  Further, a guide member 12 made of a transparent member that can be exchanged by attaching and detaching is fitted on the irradiation surface of the housing portion 11 facing the recording medium 3. The guide member 12 can use glass, for example, quartz glass, resin (UV light resistant), or the like as a transparent member. When the guide member 12 is formed of the same metal material as the light shielding cover portion 11a, the same effect is obtained even if the slit 12a is directly formed in the light shielding cover portion 11a.

  When the guide member 12 is made of glass so as to be replaceable, even the UV light that is emitted from the light emitting element 14, is irregularly reflected on the wall surface in the casing portion, and cannot pass through the slit 12 a, Through the glass, it can reach the recording medium, and the emitted irradiation power can be efficiently irradiated to the outside. In such a case, the inner surface of the housing part 11 may be subjected to a mirroring process such as a polishing process or a plating process to increase the reflection efficiency and make it difficult to attach floating substances.

  The guide member 12 is formed with a slit 12 a serving as an opening having a length corresponding to a storage area (or a landing area of UV ink) in the width direction (main scanning direction) of the recording head 8. The slit 12a has at least a slit width through which the UV light condensed by the condenser lens 15 can pass. The slit width is about 5 mm in the transport direction, and is an opening area of several percent compared to the total area of the cover portion 11a described above.

  With such a configuration of the casing unit 11, the portion other than the slit 12 a is shielded and shielded from the outside, and UV light from the light emitting element 14 is prevented from being irradiated from other than the slit 12 a and includes ink mist. It is difficult for floating substances to enter the housing from the outside.

The condensing lens 15 of this embodiment is formed of a glass material having a refractive index of 1.46 to 1.48 in the vicinity of the wavelength λ = 365 nm to 405 nm. Specifically, synthetic quartz or natural quartz can be used. In FIG. 1, the shape of the lens shows a cylindrical type, but a rod type lens can also be used, and is not particularly limited.
The condenser lens 15 emits the UV light incident from the light emitting element 14 toward the slit 12a and condenses the emitted light.

  As shown in FIG. 6, the condensing lens 15 is designed with lens characteristics so that the condensed UV light is set to a condensing point (conjugate image of the light source) in the housing part inside the slit 12a. Or the position of the optical system member such as the light emitting element 14 and the condenser lens 15 is adjusted. Further, in the direction perpendicular to the optical axis of the irradiation light of the UV light, the slit 12a has an opening width through which UV light having a light beam diameter smaller than the width of the condensing lens 15 passes, and a conjugate image of the light source (condensing point). ) Is adjusted so as to be located in the casing. Note that the opening width of the slit 12a is about the same as the diameter of the light beam passing therethrough. By such adjustment, the opening area of the slit 12a becomes smaller than the area of the effective surface of the lens 15 on the conjugate image side. Thereby, invasion of ink mist into the housing portion 11 can be suppressed.

The UV light irradiation unit 5 irradiates UV light having a radiation intensity of about 500 to 1000 mW / cm ^{2 in} the vicinity of the slit 12a. Accordingly, the ink that has landed on the recording medium 3 is fixed and cured by irradiation for about 0.15 to 0.5 sec. The peak wavelength of the UV light in the present embodiment is 385 nm, but may partially include visible light.

  In the configuration as shown in FIG. 5, even if the minute suspended matter 17 including the ink mist 9a flowing along the air flow generated along with the conveyance of the recording medium 3 flows in the vicinity of the slit 12a, most of the ink mist 9a. Can pass along with the recording medium 3 or adhere to the recording medium 3 or the cover portion 11a, and can prevent the slit 12a from entering the housing portion 11. The suspended matter 17 includes, for example, not only dust, dust, or paper powder in the atmosphere, but also those having ink mist attached thereto.

  Since the cover portion 11a and the recording medium 3 are both in a flat plate shape and are in a parallel relationship, the moving speed and the traveling direction of the suspended matter including the flowing ink mist are restricted. In general, as is known as Newton's viscosity law, a velocity distribution due to the viscosity of the gas occurs between the moving plates. Specifically, the flow velocity of the airflow generated in the vicinity of the surface of the recording medium 3 is equivalent to the conveyance speed of the recording medium 3 of 500 mm / s, that is, about 500 mm / s. On the other hand, the speed in the vicinity of the fixed shielding plate surface is about 0 mm / s. The velocity of the atmosphere in these intermediate regions is distributed so as to be approximately proportional to the distance from the parallel plate.

  Further, the interior of the UV light irradiation unit 5 is configured to shield the air current around the light source and the UV light, except for the slit 12a. That is, it is configured so that the airflow does not constantly enter the slit 12a. Furthermore, the pressure decreases near the surface of the recording medium 3 conveyed at high speed, and the inside of the casing 11 becomes a relatively positive pressure, so that the floating substance 17 including the ink mist 9 enters through the slit 12a. Suppress.

However, since the slit 12a is open, it is assumed that the ink mist 9 enters the housing portion 11 although it is slight. Hereinafter, the situation where the ink mist 9 enters the housing portion 11 will be described.
The ink mist 9b that has entered the housing portion 11 from the slit 12a is substantially shielded by the light shielding cover portion 11a and the guide member 12, and thus is not significantly affected by the airflow generated by the conveyance of the recording medium 3. For this reason, as shown in FIG. 7, the speed of the ink mist that has entered the housing portion 11 is approximately 0 mm / s, and it floats in the housing portion 11 in a random direction at an extremely low speed.

  Since the optical path of the UV light is formed in the housing part 11 from the condenser lens 15 toward the slit 12a, the ink mist 9b that has entered the optical path is cured. Furthermore, in the case of the present embodiment, a conjugate image, that is, a condensing point is provided before entering the opening (inside the casing 11). In this conjugate image, the curing energy is very high, and the curing efficiency is remarkably high with respect to UV light in the vicinity of the slit 12a. Specifically, if the light beam diameter in the slit 12a is about 10 mm and the light beam diameter in the conjugate image is about 1 mm, the light intensity in the conjugate image is about 10 times that of the slit 12a.

  Therefore, the ink mist 9b that has entered the housing 11 from the slit 12a is likely to pass through a conjugate image of UV light or an optical path in the vicinity of the conjugate image in the process toward the condenser lens 15, and stronger irradiation energy is obtained. Given it will cure quickly. The cured ink mist is granulated and loses its viscosity, so that the fixing property is lowered. Therefore, the ink mist does not adhere to the condensing lens 15 and lens contamination is prevented. Further, when the ink is composed of a cation system or a radical system, the ink mist 9b is cured if the irradiation time is about 1 second when passing through the focal point.

  As described above, according to the present embodiment, first, the UV light irradiation unit 5 includes an optical system member including the plurality of light emitting elements 14 and the condenser lens 15 in the housing unit 11. Since the structure other than the narrow slit smaller than the lens opening is shielded, it is possible to suppress the intrusion of the floating substance including the ink mist from the outside.

  Secondly, the ink mist that has entered the housing 11 is not significantly affected by the airflow generated by the conveyance of the recording medium 3, and it takes a long time to reach the optical system member by moving at low speed. , The progress of dirt due to adhesion can be delayed.

  Third, the ink mist that has entered the casing 11 has set the conjugate image (condensing point) of the UV light that has the maximum radiation intensity on the incident side of the opening (inside the casing). When passing through the conjugate image or the optical path in the vicinity thereof, the ink mist can be quickly cured, and the fixing property (viscosity) to the inside of the casing 11 or the optical system member can be largely lost.

Next, a second embodiment of the present invention will be described.
FIG. 8 is a cross-sectional view showing a conceptual configuration of the UV light irradiation unit 5 of the second embodiment. FIG. 9 is a diagram illustrating an external configuration of the UV light irradiation unit 5 viewed from the UV light irradiated side (recording medium side). FIG. 10 is a diagram illustrating an irradiation state in which UV light is irradiated in the appearance configuration in FIG. 9. In the first embodiment described above, the opening is an example configured with one slit, but in this embodiment, a plurality of circular openings are opened, and the irradiation range is overlapped from each location. It is the structure which irradiates UV light so that it may have. In the image recording apparatus of the present embodiment, the components other than the UV light irradiation unit 5 are the same as those of the first embodiment described above, and the same reference numerals are used and the description thereof is omitted.

  As shown in FIG. 8, a plurality of divided UV light irradiation units 30 (30a, 30b, 30c...) Are arranged at equal intervals on the cover portion 31 of the housing unit 11 of the UV light irradiation unit 5 of the present embodiment. Has been. Each divided UV light irradiation unit 30 includes a light emitting element 14 made of an ultraviolet LED element and a condensing lens 15 for irradiating UV light in a housing unit 11, and an opening 32 provided in a cover unit 31. It is the structure which irradiates the UV light condensed from.

  In this arrangement, for example, as shown in FIG. 9, the guide member 32 is detachably fitted in the cover part 31 of the housing part 11 in an even arrangement. The cover part 31 is formed of a light shielding member such as metal. The guide member 32 is made of a transparent member such as glass or resin (UV resistant light) or a light shielding member such as metal, and a circular opening 32a is opened at the center thereof. When the guide member 32 is formed of the same metal material as that of the cover portion 31, the cover portion 31 itself may have a circular opening 32a. The guide member 32 has the same function even if it is formed of the same metal material as that of the cover portion 31.

  As shown in FIGS. 8 and 9, the openings 32 a are provided so as to be evenly arranged corresponding to the emission optical systems including the respective light emitting elements 14 and the condenser lens 15. The light emitted from the opening 32a has a spot shape as shown in FIG. 14 to be described later, but the irradiation area increases as the distance from the opening 32a increases. Therefore, one point in the irradiation area is irradiated with UV light from a plurality of openings. Therefore, the irradiation light becomes substantially uniform on the print medium surface, and the incident angle of the irradiation light can be plural, which is suitable for irradiating a flat medium such as an ink jet print surface.

As shown in FIG. 10, the recording medium 3 on which the ink has landed is irradiated with UV light with a substantially uniform light intensity by arranging the irradiation areas 33 by the divided UV light irradiation units 30 to be the same as each other. be able to.
The arrangement of the openings is not limited to the arrangement shown in FIG. 10, and any arrangement may be used as long as the irradiated UV light is distributed with a uniform intensity. Similarly, the shape of the opening surface of the opening is not limited to a circle, and the shape of the opening surface may be another shape such as a rectangle or an ellipse.

  As described above, according to the UV light irradiation unit 5 of the present embodiment, in addition to the effects of the first embodiment described above, the UV light irradiation opening is developed on a plurality of circular openings. Therefore, the irradiation time to the recording medium being conveyed can be lengthened. In addition, since the condensing point of the UV light is set in the vicinity of the opening, the circular opening has a small diameter and the structure other than the opening is shielded, so that the floating substance including the ink mist enters from the outside. Can be suppressed.

Next, a third embodiment of the present invention will be described.
FIG. 11 shows an opening 12b that is opened obliquely so that the UV light irradiation unit 5 in the present embodiment has an acute angle of attack with respect to the recording medium conveyance direction. In other words, the present embodiment has an opening that opens in a non-parallel manner by inclining the direction of the optical axis and the central axis direction of the opening provided in the direction perpendicular to the conveyance direction of the recording medium in the first embodiment. 12b is provided. As shown in FIG. 11, the light emitting unit 14 and the condenser lens 15 are arranged in an oblique direction so that UV light is irradiated along the opening direction.

  As described above, the suspended matter 17 including the ink mist 9a is regulated by the light shielding cover portion 11a and flows along the conveyance direction of the recording medium 3, as shown in FIG. By providing an angle of attack in the opening direction with respect to the flowing direction, it is difficult for the ink mist 9b to enter from the opening 12b. Even if the ink mist 9b enters from the opening 12b, since the optical system member such as a condenser lens is not disposed in the traveling direction, the problem of soiling the optical system member due to ink mist adhesion is further improved. . Further, when the ink mist 9b enters through the opening 12b, the ink mist 9b passes through the conjugate image of the ultraviolet light set in front of the opening 12b (inside the housing), so at least the surface of the ink mist is cured. As a result, the fixing property due to adhesion is lost, and the occurrence of contamination in the casing 11 is remarkably improved.

  As described above, according to the present embodiment, in addition to the effect of the first embodiment described above, when the generated ink mist floats in the recording medium conveyance direction, the opening 12a has an acute angle of attack. By opening in the direction, entry of ink mist can be further suppressed. Furthermore, even if there is a floating substance that moves downstream in the conveyance direction, fixing can be prevented, and problems such as contamination on the optical system member can be remarkably improved.

Next, a fourth embodiment of the present invention will be described.
FIG. 12 shows light-emitting elements 14a, 14b, 14c and condenser lenses 15a, 15b that emit UV light from different directions so that the UV light irradiation unit 5 in this embodiment passes through one opening 12a. 15c shows a configuration example in which three sets of irradiation optical systems are arranged in the casing 41.

  In this example, the three sets of irradiation optical systems are arranged so as to spread in the width direction of the recording medium 3, and the set of the light emitting element 14a and the condensing lens 15a arranged at the center position has UV in the central portion of the recording medium. Irradiate light. Another set of the light emitting element 14b and the condensing lens 15b and the set of the light emitting element 14c and the condensing lens 15c irradiate UV light from an oblique direction to different end portions of the respective recording media. Further, both conjugate images (condensing points) are arranged at individual positions in the casing 41 that do not match before the opening.

  According to this embodiment, since the man-hour for forming the three openings can be realized by the man-hour for forming one opening, the processing cost due to the reduction in the number of openings can be reduced. Further, by reducing the number of openings, it is possible to suppress the number and opportunities of ink mist entering the casing.

  FIG. 13 is a diagram showing a modification of the fourth embodiment. Each set of irradiation optical systems has both conjugate images (condensing points) in the casing 41 at the same position before the opening. The example of a structure arrange | positioned so that it may correspond is shown. In this modification, the same effect as that of the above-described fourth embodiment can be obtained, and furthermore, since the conjugate images match, it is possible to enhance the irradiation energy for curing with UV light.

The positions of the conjugate images according to the first to fourth embodiments described above may be set to the positions shown in FIGS.
FIG. 14 is a first example in which the position of the conjugate image of the UV light emitted from the light source is set in the opening 12b. FIG. 15 is a diagram in which the optical system has the same arrangement as FIG. 14 and the position of the conjugate image of the UV light is viewed from below the opening 12a. Here, the opening 12a includes both the slit shown in FIG. 4 and the circular opening 32a shown in FIG.

  Thus, when the position of the conjugate image (condensing point) is set within the range in the opening 12a, the opening area can be minimized without loss of irradiation light as in the optical path shown in FIG. . That is, the area of the opening can be made much smaller than the area of the effective surface of the optical member, for example, the condenser lens 15 (the region through which UV light passes), and the entry of minute droplets can be minimized. Can do.

  As a next example, as shown in FIG. 17, in the second example, the position of the conjugate image (condensing point) of the UV light emitted from the light source is set inside the housing 11 before the opening 12a. is there. Since the UV light that has passed through the conjugate image has a divergence angle, in the case of the thick opening portion 12a, the opening shape in FIG. 16 generates restrictions due to the opening wall surface, bending of the optical path due to irregular reflection, and the like. Further, the opening may be provided with a slope that spreads. That is, the wall surface inclination of the opening 12a is designed to be equal to or greater than the spread angle of the UV light.

  Thus, by providing the opening 12a with an expanding inclination, that is, by forming the opening 12a in a tapered shape, the opening area on the incident side can be minimized to the extent that the processing tolerance is limited. In addition, this tapered shape makes the opening 12a smaller in the inner opening area than in the outer opening area, so that it is difficult for ink mist and the like to enter the casing, and the position of the conjugate image is set on the irradiation side of the opening. By making the inside from the surface of the ink, the minute ink mist that tries to enter the casing part passes or floats on the optical path near the conjugate image, and at least the hardening of the surface of the ink mist is promoted, and the fixing property is increased. Can be lowered.

[Image recording device]
The image recording apparatus of each embodiment described above is not necessarily limited to an image recording apparatus, that is, a printer apparatus. For example, it can be used for a color filter manufacturing device, a three-way shape forming device, a printing machine, a dispensing device, a precision medical device, a curing device, a bonding device, a coating film forming device, a rapid model forming device, a production device, and the like. In addition, a mobile order ink jet printer and a barcode reader can be combined to form an ordering / ordering system for use outdoors or in an airplane. Since fixability and the like are improved, a character recognition system may be configured as an OCR (Optical Character Reader) device. Moreover, in the said Example, since ultraviolet light is irradiated, you may comprise the sterilizer for medical devices which performs ultraviolet disinfection at the time of the printing of a package.

  Further, the ternary shape forming apparatus applies an adhesive to a powder or the like from an ink jet head and cures it, and then removes the powder to form a three-dimensional shape. Therefore, any material may be used as long as the liquid droplets are landed on an arbitrary surface and cured.

[recoding media]
In each of the embodiments described above, a long roll paper is described as the recording medium. However, the recording medium that can be employed in each embodiment is not limited, and can be cured by landing ultraviolet ink. Thus, the choice of media material is relatively free. For example, polycarbonate, acrylic resin, ABS, polyacetal, rubber or the like can be used as the recording medium. A film can also be used. For example, a PET film, a TAC film, etc. can be used. In addition, metal, glass, resin, wood, paper, coated paper, plain paper, cardboard, or the like can be used.

[Light source wavelength and ink type in the light irradiation section]
In each of the above-described embodiments, the ultraviolet light curing ink is taken as an example of the combination of the ink and the curing light source, and the combination of the UV light irradiation unit is taken as an example. However, the present invention is not limited to this. For example, a combination of a water-based ink and a curing light source that cures by an evaporation reaction by radiant heat may be used. In the case of this combination, it is preferable that the curing light source uses a wavelength longer than infrared light. That is, not only ultraviolet light but also general electromagnetic waves such as infrared light, visible light, and microwaves can be used.

[Conjugate image (focusing point)]
In each of the embodiments described above, by setting the position of the conjugate image in front of the opening in the space inside the casing, floating matter (including ink mist) that may enter the casing from the opening is used. On the other hand, it is possible to selectively irradiate an electromagnetic wave having the maximum radiation intensity.

  Furthermore, it is possible to selectively irradiate an electromagnetic wave having a maximum radiation intensity with respect to a floating substance that has already entered and floated in the casing. Accordingly, the hardening is strongly promoted until the floating material reaches the position of the optical system component provided at a position substantially opposite to the opening, and the fixing property can be strongly lost.

  When the floating material passes through the optical path of the irradiation light, the size of the opening is about several mm, whereas the size of the floating material is about several μm, and the floating material stops at a certain place. Therefore, it does not substantially affect the light irradiation on the moving medium.

  Therefore, the present invention is suitable for a curing light source for irradiating a moving medium. In addition, when there is no floating substance in the optical path, there is no shielding and all electromagnetic waves are irradiated to the moving medium, and the irradiation efficiency is not impaired. Therefore, the curing light source of the present invention is suitable for irradiating a medium moving at high speed.

Each embodiment described above includes the following gist.
(1) A transport mechanism that transports a recording medium, an inkjet printer that ejects UV curable ink toward the transported recording medium to form an image on the recording medium, a light source that emits UV light, and the light source A condensing member that focuses the emitted UV light to form a conjugate image (focal point) of the light source, and holds the light source and the condensing member inward so as to surround and emits the light from the condensing member. An ink jet printer that has a housing formed with an opening through which UV light passes so as to face the surface of the recording medium, and irradiates the recording medium with UV light to cure the UV curable ink on the recording medium The condensing member is held inside the casing so as to form a conjugate image (focal point) of UV light from the light source inward from the opening tip of the casing. Inkjet printer Rinta. (Effect) Since the probability that the ink mist that has entered the casing is irradiated to the focal point having the highest curing efficiency is increased, the ink mist can be cured before adhering to the light collecting member.

  (2) The condensing member is held inward of the casing so as to form a conjugate image of the light source in an opening in the casing. Inkjet printer. With this configuration, by setting a conjugate image in the opening, the beam diameter in the opening is reduced. Therefore, the opening area can be reduced. As a result, the amount of ink mist entering from the opening can be reduced.

(3) The inkjet printer according to (1), wherein the opening is formed in a tapered shape (cone shape) so that the opening area decreases from the outside toward the inside. . With this configuration, the ink mist can be prevented from entering and the curing probability can be increased. (4) An image recording unit that records an image composed of an ink layer on a recording medium;
A light irradiation unit for irradiating the ink layer with a curing light beam;
In an image recording apparatus having
The light irradiator is
A light source that emits a curing light beam;
A condensing member that condenses the luminous flux emitted from the light source;
An opening formed in the width or diameter of the light beam that allows the light beam emitted from the light collecting member to pass therethrough, and formed opposite to the recording surface of the recording medium. A housing part containing the light source and the light collecting member so as to be shielded;
Have
The condensing member forms a conjugate image of light emitted from the light source at a position before the opening, and then passes the opening to irradiate the ink layer with a curing light beam. Image recording device.

  DESCRIPTION OF SYMBOLS 1 ... Image recording device, 2 ... Image recording part, 3 ... Recording medium, 4 ... Platen, 5 ... UV light irradiation part, 6 ... Processing accommodation part, 7 ... Conveyance mechanism, 8 ... Recording head, 9 ... UV ink droplet, 9a, 9b ... ink mist, 10 ... control unit, 11 ... housing unit, 11a ... cover unit, 12 ... guide member, 12a ... slit or opening 13 ..., 14 ... light emitting element, 15 ... condensing lens, 16 ... Cut part, 17 ... suspended matter, 18 ... external equipment.

Claims (8)

An image recording unit for recording an image on a recording medium;
A light irradiation unit for irradiating the image with light and fixing the image on the recording medium;
In an image recording apparatus having
The light irradiator is
A light source that emits light;
A condensing member that focuses light emitted from the light source;
A housing that includes the light source and the light collecting member, and an opening through which the light emitted from the light collecting member passes is formed to face the recording medium surface;
Comprising
The image recording apparatus according to claim 1, wherein the condensing member forms a conjugate image obtained by condensing light emitted from the light source at a position before the opening, and then allows the light to pass through the opening.   The image recording apparatus according to claim 1, wherein the condensing member is disposed and held in the casing so as to form the conjugate image in the opening.   The opening of the casing is formed in a tapered shape in which the opening area of the opening gradually increases from the incident side to the emission side according to the spread of the light that has passed through the conjugate image. The image recording apparatus according to claim 2. A transport unit for transporting the recording medium;
The image recording unit records an image on the recording medium conveyed by the conveyance unit;
The image recording apparatus according to claim 2, wherein the opening portion of the housing portion is formed to be inclined so as to have an acute angle of attack with respect to a conveyance direction of the recording medium.   The image according to claim 2, wherein the opening of the casing is formed so that an inclination of a central axis of the opening intersects an optical axis of a light beam emitted from the light collecting member. Recording device. The light irradiation unit has a plurality of sets including the light source and a light collecting member,
The plurality of light collecting members are held in the housing portion so that the plurality of light beams emitted from the respective light collecting members of each set pass through one opening formed in the housing portion. The image recording apparatus according to claim 1, wherein the image recording apparatus is characterized.   The opening of the casing is formed so as to be larger than a diameter of light passing through the opening and smaller than an irradiation area when the recording medium is irradiated with light. Item 2. The image recording apparatus according to Item 1.   The image recording apparatus according to claim 1, wherein the opening of the casing is formed to be larger than a diameter of light passing through the opening and smaller than the light collecting member.

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