JP2005313445A - Ink jet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an ink jet recorder in which the quantity of UV-rays sufficient for curing ink can be ensured even when a low output UV-irradiator is employed while reducing the overall size. <P>SOLUTION: In the ink jet recorder comprising a recording head having nozzles for ejecting UV-curing ink onto a recording medium, a UV-irradiator equipped with a UV-light source for irradiating the recording medium with UV-rays after ink is ejected thereto thus curing the ink, and a carriage moving in the main scanning direction while mounting a plurality of recording heads and UV-ray irradiators, the UV-ray irradiators are arranged on the opposite sides of the recording head on the carriage, and also arranged on the downstream side in the carrying direction of the recording medium on the carriage. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus using an ultraviolet curable ink.

  2. Description of the Related Art Conventionally, many image recording apparatuses using an inkjet method have been used as image recording means capable of recording an image easily and inexpensively. An ink jet recording apparatus uses, for example, a piezoelectric element such as a piezo element or a heater to eject ink from a nozzle of a recording head toward a recording medium as fine droplets, and performs recording while penetrating or fixing the ink to the recording medium. An image is recorded on the recording medium by moving the head on the recording medium.

  Further, in recent years, an ultraviolet curable ink jet recording apparatus has been known as a means for forming an image even on a recording medium such as a resin film having poor ink absorbability. This is because ultraviolet curable ink containing a photoinitiator having a predetermined sensitivity to ultraviolet rays is used, and the ink that has landed on the recording medium is irradiated with ultraviolet rays so that the ink is cured and fixed on the recording medium. It is possible to print easily even on transparent or opaque packaging materials.

  In an ink jet recording apparatus used for such ultraviolet curable ink jet recording, as shown in FIG. 4, an ultraviolet light source for curing ink is usually provided on both sides of the carriage recording head in the main scanning direction. When an image is recorded on a recording medium, the ink is cured by irradiating ultraviolet rays from an ultraviolet light source immediately after the ink has landed on the recording medium.

  Therefore, in order to obtain a sufficient amount of light from the ultraviolet light source and to cure the ink easily and reliably and prevent the ink from spreading, the length of the ultraviolet light source in the sub-scanning direction is set to be twice or more that of the recording head, An ink jet recording apparatus that cures ink by irradiating a plurality of times is known (Patent Document 1).

Here, among the ultraviolet curable inks, the cationic polymerizable ink has high sensitivity, and the reaction proceeds once it is irradiated with ultraviolet rays. Therefore, even when a low output type ultraviolet irradiation device is used, a plurality of ultraviolet irradiations are performed. The ink can be cured by repeating the operation or extending the ultraviolet irradiation time. For this reason, if a cationically polymerizable ink is used, the ink can be reliably cured even when a low output type ultraviolet irradiation device is used by increasing the number of times of ultraviolet irradiation as in Patent Document 1. It is.
JP 2004-1326 A

  However, in the conventional ink jet recording apparatus, since the length dimension of the ultraviolet light source in the sub-scanning direction is more than twice that of the recording head, the number of UV irradiations increases, but the length dimension of the carriage in the sub-scanning direction increases. There was a problem to do.

  Therefore, in order to secure an ultraviolet light quantity sufficient for ink curing while suppressing an increase in the length dimension of the carriage in the sub-scanning direction, the width of the ultraviolet irradiation device is increased in the main scanning direction as shown in FIG. An ink jet recording apparatus in which the irradiation time of ultraviolet rays is extended is known. However, in this case, since the width of the carriage in the main scanning direction is increased, the entire carriage cannot be reduced in size and weight.

  On the other hand, when the secondary exposure is provided on the downstream side in the conveyance direction of the recording medium, an ultraviolet light source corresponding to the width of the recording medium is required, which is inefficient when the width of the recording medium is small, and at the same time, an inkjet recording apparatus Will lead to an increase in size.

  The present invention has been made in view of the above points, and even when a low-output type ultraviolet irradiation device is used, the number of ultraviolet irradiations can be increased to obtain a sufficient amount of ultraviolet light for ink curing, and inkjet An object of the present invention is to provide an ink jet recording apparatus capable of reducing the size of the recording apparatus.

  In order to solve the above-described problem, an ink jet recording apparatus according to claim 1 includes a recording head formed with a nozzle for discharging an ultraviolet curable ink onto a recording medium, an ultraviolet ray on the recording medium after the ink has landed. And a carriage having the plurality of recording heads and the ultraviolet light source mounted thereon, the ultraviolet light source being in the direction of transport of the recording medium with respect to the recording head of the carriage Are arranged on both sides in a direction perpendicular to the recording medium and on the downstream side of the carriage in the conveyance direction of the recording medium.

According to the first aspect of the present invention, after the ultraviolet rays are irradiated from the ultraviolet light sources arranged on both sides in the direction perpendicular to the conveyance direction of the recording medium with respect to the recording head of the carriage, By irradiating ultraviolet rays from an ultraviolet light source arranged on the downstream side in the transport direction, the number of ultraviolet irradiations is increased, so that a sufficient amount of ultraviolet light can be obtained for curing of the ink ejected to the recording medium. In addition, even when using a low-output type UV light source, sufficient UV light can be obtained by taking advantage of the characteristics of the cationically polymerizable ink that accumulates and cures the ink by multiple irradiations even with a small amount of UV light. The amount of light can be obtained.
Further, since the ultraviolet light source is arranged taking advantage of the space downstream of the carriage in the conveyance direction of the recording medium, the width of the carriage does not spread in the main scanning direction.

  The invention according to claim 2 is the ink jet recording apparatus according to claim 1, wherein the ultraviolet light source disposed on both sides of the carriage in a direction perpendicular to the recording medium conveyance direction with respect to the recording head of the carriage An ultraviolet light source disposed on the downstream side in the conveyance direction of the recording medium of the carriage is integrally formed.

  According to the second aspect of the invention, the number of low-pressure mercury lamps or the like that are ultraviolet light sources can be reduced, and the ultraviolet light source can be unified.

  A third aspect of the invention is the ink jet recording apparatus according to the second aspect, wherein the ultraviolet light source has a U-shape.

  According to the third aspect of the present invention, the space on both sides in the direction perpendicular to the recording medium conveyance direction and the downstream side in the conveyance direction of the recording medium in the carriage is efficiently utilized with respect to the carriage recording head. Space for arranging the light source can be secured.

  The invention according to claim 4 is the ink jet recording apparatus according to any one of claims 1 to 3, wherein the ink is a cationic polymerizable ink.

  According to the invention described in claim 4, while using a cationically polymerizable ink having high sensitivity and capable of using a low-output type ultraviolet irradiation device, The same operation as the ink jet recording apparatus described can be obtained.

  According to the first aspect of the present invention, by efficiently securing the space of the ultraviolet light source around the carriage, the carriage can obtain a sufficient amount of ultraviolet light for ink curing even in a low output type ultraviolet irradiation device. Can be minimized.

  According to the invention described in claim 2, by reducing the number of low-pressure mercury lamps that are ultraviolet light sources and the number of power supplies, the manufacturing cost is reduced and the frequency of malfunction due to disconnection of the wiring is reduced. can do.

  According to the third aspect of the present invention, by efficiently securing a space for arranging the ultraviolet light source, even with a low output type ultraviolet irradiation device, while obtaining a sufficient amount of ultraviolet light for ink curing, Increase in size can be minimized.

  According to the invention described in claim 4, while using a cationically polymerizable ink having high sensitivity and capable of using a low-output type ultraviolet irradiation device, The same effects as those of the described ink jet recording apparatus can be obtained.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples, and it is needless to say that various modifications can be made without departing from the scope of the invention.
(First embodiment)

  As shown in FIG. 1, the ink jet recording apparatus of the present embodiment is provided with a platen 5 that supports the recording medium P from below. A transport device 6 such as a roller for transporting the recording medium P is disposed so as to sandwich the platen 5 upstream and downstream of the transport direction (hereinafter referred to as sub-scanning direction Y) of the recording medium P on the platen 5. A pair of guide rails 7 extending in a direction perpendicular to the sub-scanning direction Y (hereinafter referred to as main scanning direction X) is provided above the platen 5. A carriage 1 is supported on the guide rail 7 so as to be reciprocally movable in the main scanning direction X.

As shown in FIG. 1, a recording head 2 that discharges yellow (Y), magenta (M), cyan (C), and black (K) inks on a recording medium P is mounted on the carriage 1. Has been. The color of the ink used in the ink jet recording apparatus is not limited to this, and for example, light yellow (LY), light magenta (LM), light cyan (LC), or the like can be used.
In the recording head 2, a plurality of nozzles (not shown) for ejecting ink are arranged along the sub-scanning direction Y.

  Here, the ink used in this embodiment will be described. When the ink is cured, the polymerizable compound contained in the ink undergoes a polymerization reaction. In this embodiment, the ink includes an activation energy ray-curable compound as the polymerizable compound, and the activation energy that initiates the polymerization reaction. As an ultraviolet curable ink using ultraviolet rays.

  The ultraviolet curable ink is roughly classified into a radical polymerizable ink and a cationic polymerizable ink, and both inks can be applied as the ink used in the present embodiment. The radical polymerizable ink, the cationic polymerizable ink, Alternatively, a hybrid type ink may be applied.

However, cationically polymerizable inks are attracting attention as inks that have high sensitivity and can use low-output type ultraviolet irradiation devices. In addition, since cationic polymerizable inks have the feature of storing light energy, even a small amount of UV light accumulates over time, and eventually cures the ink, resulting in a lower output type. Suitable for UV irradiation equipment.
Furthermore, the cationic polymerizable ink has very little inhibition of the polymerization reaction by oxygen and is excellent in functionality and versatility.

  Therefore, in this embodiment, a cationic polymerizable ink is used in particular. A cationically polymerizable ink is a mixture containing at least a cationically polymerizable compound such as an oxetane compound, an epoxy compound, or a vinyl ether compound, a photocationic initiator, and a coloring material, and has a property of being cured by irradiation with ultraviolet rays. It is.

  Next, as shown in FIG. 1, both ends of the recording head 2 of the carriage 1 in the main scanning direction X are irradiated with ultraviolet rays to the ink ejected from the nozzles onto the recording medium P to cure the ink. An ultraviolet irradiation device 3a is provided. Further, on the downstream side of the carriage 1 in the sub-scanning direction Y, an ultraviolet irradiating device 3b is arranged in parallel with the main scanning direction X, and a position covering the downstream end of the ultraviolet irradiating device 3a in the sub-scanning direction Y. It extends to.

The ultraviolet irradiation devices 3a and 3b are provided with a cover member, and ultraviolet rays are irradiated radially by the ultraviolet light sources 4a and 4b provided therein.
As the ultraviolet light sources 4a and 4b, any of a high output type such as a high pressure mercury lamp and a metal halide lamp and a low output type such as a low pressure mercury lamp, a cold cathode tube and an LED can be used. The low output type ultraviolet light sources 4a and 4b are preferably used.

  As the recording medium P used in the present embodiment, various papers such as plain paper, recycled paper, and glossy paper, various fabrics, various nonwoven fabrics, resin, metal, glass, and the like, which are applied to a normal inkjet recording apparatus. Can be applied. Moreover, as a form of the recording medium P, a roll shape, a cut sheet shape, a plate shape, or the like is applicable. Further, known opaque recording media P such as various papers whose surfaces are coated with a resin, a film containing a pigment, and a foamed film are also applicable.

  Next, the operation of the ink jet recording apparatus in this embodiment will be described.

  In the ink jet recording apparatus of the present embodiment, the cation polymerizable ink of each color from the nozzles of the recording head 2 mounted on the carriage 1 while the carriage 1 reciprocates in the main scanning direction X along a carriage rail (not shown). Is discharged. Then, the ink that has landed on the recording medium P is irradiated with ultraviolet rays from the ultraviolet light sources 4a and 4b of the ultraviolet irradiation devices 3a and 3b that have moved above the ink that has landed along with the movement of the carriage 1, thereby curing the ink. Then, the image is fixed on the recording medium P.

  Here, as described above, in the present embodiment, after ultraviolet rays are irradiated from the ultraviolet light sources arranged on both sides of the recording head of the carriage in the main scanning direction X, the downstream side of the carriage in the sub-scanning direction Y is applied. By irradiating ultraviolet rays from the arranged ultraviolet light source, the number of times of ultraviolet irradiation is increased, so that it is possible to obtain a sufficient amount of ultraviolet rays for curing the ink ejected to the recording medium. In addition, even when using a low-output type UV light source, even with a small amount of UV light, taking advantage of the characteristics of cationically polymerizable ink that accumulates and cures the ink by multiple irradiations, sufficient UV light is used. The amount of light can be obtained.

Further, since the ultraviolet irradiation devices 3a and 3b are arranged on the side surface of the carriage 1 on which the recording head 2 is mounted, the size of the ultraviolet irradiation devices 3a and 3b greatly affects the size of the carriage. In addition to the ultraviolet irradiating device 3a, the ultraviolet irradiating device 3b is arranged taking advantage of the space on the downstream side in the sub-scanning direction Y of the carriage 1, so that the width of the carriage 1 is expanded in the main scanning direction X. In addition, the enlargement of the carriage 1 can be minimized while ensuring the amount of ultraviolet light.
(Second Embodiment)

  Next, a second embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the same part as 1st Embodiment, the description is abbreviate | omitted, and a different part from 1st Embodiment is demonstrated.

As shown in FIG. 2, in the present embodiment, the ultraviolet light sources 4 a disposed on both sides of the recording head 2 of the carriage 1 in the main scanning direction X and the downstream side of the carriage 1 in the sub-scanning direction Y are disposed. The ultraviolet light source 4b is integrally formed as a single ultraviolet light source 4c, and is disposed so as to surround the recording head 2.
As the ultraviolet light source 4c in this embodiment, a low-pressure mercury lamp that can be freely deformed is particularly preferably used. The low-pressure mercury lamp is processed and deformed into a U shape as shown in FIG. 2 is arranged so as to surround 2.
Further, as shown in FIG. 3, after the low-pressure mercury lamp is bent twice on one side in the direction perpendicular to the recording medium conveyance direction with respect to the recording head 2 of the carriage 1, the conveyance direction of the recording medium P in the carriage 1 is obtained. The recording head 2 can also be arranged so as to be bent twice on the opposite side of the carriage 1 through the downstream side.

  With the configuration as described above, the same effects as those of the first embodiment can be obtained, and the number of low-pressure mercury lamps and the like can be reduced. Further, since the ultraviolet light sources 4a and 4b are unified as the ultraviolet light source 4c, the number of power sources can be reduced.

As described above, according to the inkjet recording apparatus of the present invention, the space for the ultraviolet irradiation device 3 is efficiently secured around the carriage 1, thereby extending the ultraviolet irradiation time and using a low output type ultraviolet light source. Even in such a case, it is possible to obtain a sufficient amount of ultraviolet light for curing the ink, and it is possible to reduce the size of the ink jet recording apparatus by reducing the size of the carriage 1.
In addition, the number of low-pressure mercury lamps, which are ultraviolet light sources, can be reduced, and the number of power supplies can be reduced by unifying the ultraviolet light sources, thereby reducing the number of wirings and reducing manufacturing costs. The frequency of malfunctions can be reduced.

FIG. 1 is a plan view schematically showing a carriage and an ultraviolet irradiation device in the first embodiment. FIG. 2 is a plan view schematically showing a carriage and an ultraviolet irradiation device in the second embodiment. FIG. 3 is a plan view schematically showing a carriage and an ultraviolet irradiation device according to the third embodiment. FIG. 4 is a plan view schematically showing a carriage and an ultraviolet irradiation device in a conventional ink jet recording apparatus. FIG. 5 is a plan view schematically showing a carriage and an ultraviolet irradiation device in another conventional ink jet recording apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Carriage 2 Recording head 3a, 3b, 3c Ultraviolet irradiation device 4a, 4b, 4c Ultraviolet light source 5 Guide rail 6 Conveying mechanism 7 Platen X Main scanning direction Y Sub scanning direction

Claims (4)

A recording head formed with a nozzle for discharging ultraviolet curable ink onto a recording medium;
An ultraviolet light source for irradiating the recording medium with ultraviolet rays after the ink has landed to cure the ink;
A carriage having the plurality of recording heads and the ultraviolet light source mounted thereon;
The ultraviolet light source is disposed on both sides of the carriage in the direction perpendicular to the recording medium conveyance direction with respect to the recording head, and is disposed on the downstream side of the carriage in the conveyance direction of the recording medium. Inkjet recording apparatus.   An ultraviolet light source disposed on both sides of the carriage in the direction perpendicular to the recording medium conveyance direction and an ultraviolet light source disposed on the downstream side of the carriage recording medium conveyance direction are integrated. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is formed.   The inkjet recording apparatus according to claim 2, wherein the ultraviolet light source has a U-shape.   The inkjet recording apparatus according to claim 1, wherein the ink is a cationic polymerizable ink.

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