WO2012029867A1

WO2012029867A1 - Ink-jet printer

Info

Publication number: WO2012029867A1
Application number: PCT/JP2011/069814
Authority: WO
Inventors: 加藤　茂; 加藤　鉄也; 昇修武田; 良人山口
Original assignee: 株式会社ミマキエンジニアリング
Priority date: 2010-08-31
Filing date: 2011-08-31
Publication date: 2012-03-08
Also published as: JP5584899B2; JP2012051160A

Abstract

Provided is an ink-jet printer capable of quickly curing ultraviolet curable ink and finely setting curing conditions of the ultraviolet curable ink according to the type and printing conditions of a medium. This ink-jet printer comprises: first ultraviolet curing lamp units (5a, 5b) mounted in a carriage (3) and primarily curing ultraviolet curable ink that is just ejected from an ink-jet head (H) by irradiating the ink with ultraviolet rays; and a second ultraviolet curing lamp unit (9) secondarily curing the primarily-cured ultraviolet curable ink by irradiating the ink with ultraviolet rays again. The first ultraviolet curing lamp units (5a, 5b) and the second ultraviolet curing lamp unit (9) are provided such that the interval between a medium and each unit can be adjusted.

Description

Inkjet printer

The present invention relates to an inkjet printer.

Conventionally, inkjet printers using ultraviolet curable ink are known. For example, the ink jet printer described in Patent Document 1 includes an ink head that discharges ultraviolet curable ink, and an ultraviolet lamp that irradiates ultraviolet light to the ultraviolet curable ink discharged from the ink head onto a medium. In this ink jet printer, printing is performed by curing the ultraviolet curable ink discharged from the ink head onto the medium by irradiating the ultraviolet ray with ultraviolet rays.

By the way, in an ink jet printer, an increase in printing speed is demanded while a medium size is increased. In order to realize this, it is necessary to quickly cure the ultraviolet curable ink. For this reason, an ultraviolet lamp that irradiates the ink discharged from the inkjet head onto the medium is integrally assembled with the carriage. When the carriage is scanned back and forth in the width direction of the medium (main scanning direction), the inkjet head The ultraviolet curable ink is cured by irradiating each color ink ejected on the medium with ultraviolet rays to increase the integrated light quantity.

JP 2008-229949A (FIG. 1)

In recent years, in an inkjet printer, it is necessary to quickly cure ultraviolet curable ink in order to increase the printing speed. In order to cure the ultraviolet curable ink quickly, the illuminance of the ultraviolet lamp may be increased. For this reason, it is conceivable to increase the number of ultraviolet lamps mounted on the carriage.

However, the ultraviolet lamps mounted on the carriage are equipped with LEDs in order to reduce the size and power consumption. However, increasing the number of relatively expensive LEDs increases the manufacturing cost and at the same time increases the number of relatively expensive LEDs. An increase in physical size causes a decrease in printing speed. There is also a method of increasing the illuminance of the ultraviolet lamp, but the amount of heat generation increases and the lamp life can be shortened. The illuminance of the ultraviolet lamp also affects the distance of the medium having a different thickness from the ultraviolet lamp.
In particular, since the amount of ink ejected from the inkjet head increases as the size of the medium to be printed increases, it may be assumed that curing is insufficient with only the ultraviolet lamp mounted on the carriage together with the inkjet head. Further, if the discharged ultraviolet curable ink is cured before it spreads uniformly on the medium, a streak-like pattern or the like appears on the printing surface, resulting in a problem that the printing image quality deteriorates.

The present invention has been made in order to solve the above-described problems, and is an ink jet capable of quickly curing an ultraviolet curable ink and finely setting the curing condition of the ultraviolet curable ink according to the type of medium and printing conditions. An object is to provide a printer.

In order to solve the above-described problems, an ink jet printer according to the present invention includes an ink jet head that is mounted on a carriage that reciprocates in a main scanning direction, and that discharges ultraviolet curable ink onto a facing medium, and the carriage reciprocates. An inkjet printer including a printing unit that can reciprocate in a sub-scanning direction orthogonal to a main scanning direction, wherein the printing unit is mounted on the carriage and irradiates ultraviolet curable ink that has just been ejected from the inkjet head with ultraviolet rays. First ultraviolet irradiation means for primary curing, and second ultraviolet irradiation means for performing secondary curing by irradiating ultraviolet light again to the primary cured ultraviolet curable ink, the first ultraviolet irradiation means and the second ultraviolet radiation The irradiating means is characterized in that the distance from the medium can be adjusted.

The ultraviolet curable ink immediately after being ejected from the inkjet head by the first ultraviolet irradiation means that scans in the main scanning direction is irradiated with ultraviolet rays to be primary cured, and then the primary cured ultraviolet curable ink is again irradiated with ultraviolet rays by the second ultraviolet irradiation means. Can be cured by secondary irradiation, so that the ultraviolet curable ink can be cured quickly and reliably.
In addition, since the printing unit capable of scanning in the main scanning direction and the sub-scanning direction has both the first ultraviolet irradiation unit and the second ultraviolet irradiation unit, the printing unit immediately after printing is compared with the case where either one of the ultraviolet irradiation units is fixed. In addition to increasing the amount of UV irradiation on the medium, various printing expressions such as printing the printed matter in a matte tone or printing in a glossy tone by setting the printing conditions finely by the cooperative action of the two UV irradiation means Is possible.
In particular, since the first ultraviolet irradiation means and the second ultraviolet irradiation means are provided so that the distance between the medium and the medium can be adjusted, the curing conditions of the ultraviolet curable ink are set in detail according to the type of the medium and the printing conditions. Therefore, different textures (matte, glossy, etc.) depending on printing conditions can be printed with high definition.

If an ultraviolet fluorescent lamp unit is used as the second ultraviolet irradiation means, it is cheaper than an LED, and even one can be irradiated over a wide range in the width direction of the medium. Thereby, the ultraviolet curable ink can be efficiently secondary-cured.

The second ultraviolet irradiation means is provided with an ultraviolet fluorescent lamp unit over a length equivalent to the main scanning range of the carriage. Thereby, since the scanning direction of the carriage can be covered with a single ultraviolet fluorescent lamp, it is not necessary to provide a plurality of lamps in the main scanning direction, so that uneven irradiation hardly occurs.

Also, a plurality of ultraviolet fluorescent lamps are provided in the sub-scanning direction as the second ultraviolet irradiation means, and each ultraviolet fluorescent lamp is independently controlled on and off. Accordingly, the second ultraviolet irradiation means can be appropriately selected and turned on according to the necessary ultraviolet irradiation amount. Therefore, it is possible to efficiently irradiate ultraviolet rays according to the discharge amount of the ultraviolet curable ink discharged onto the medium. Further, by turning on / off only the number of ultraviolet fluorescent lamps necessary for curing while moving the printing unit in the sub-scanning direction, the ink can be efficiently cured according to the ink discharge amount.

In the printing unit cover, a lamp housing cover for housing the ultraviolet fluorescent lamp unit is formed so as to protrude in the sub-scanning direction so as to cover the movement range of the carriage in the main scanning direction. Accordingly, the lamp housing cover can be attached / detached as an option to / from the printing unit cover, and heat generated from the ultraviolet fluorescent lamp can be easily released to the outside.

An opening / closing member that opens and closes the upper portion of the lamp housing cover is pivotably provided. The opening / closing member is made of a resin material that blocks ultraviolet rays and can be seen through the cover. The inside can be visually confirmed, and the height of the ultraviolet fluorescent lamp from the medium can be adjusted by opening the opening / closing member.

According to the present invention, the ultraviolet curable ink can be cured rapidly and the curing conditions of the ultraviolet curable ink can be set finely according to the type of medium and the printing conditions.

1 is an external perspective view of an ink jet printer. 2A and 2B are external perspective views of the ink jet printer showing the open / close state of the lamp housing cover. 3A to 3D are perspective views of the printing unit, and layout diagrams showing a planar arrangement, a front arrangement, and a side arrangement of the first ultraviolet curing lamp and the second ultraviolet curing lamp in the printer. It is the figure which looked at the lamp unit from the lower part. It is a figure which shows the structure of a lamp unit. It is a flowchart which shows operation | movement of an inkjet printer. It is a figure which shows the irradiation amount of the ultraviolet-ray in an inkjet printer. It is an expansion perspective view which shows the height adjustment mechanism of a 1st ultraviolet curing lamp. It is a partially expanded perspective view which shows the height adjustment mechanism of a 2nd ultraviolet curing lamp.

Hereinafter, embodiments of an ink jet printer according to the present invention will be described in detail with reference to the drawings. In the drawings, the same members are denoted by the same reference numerals. In the following description, the main scanning direction is the longitudinal direction of the printing unit (the direction in which the carriage reciprocates), and the sub-scanning direction is the longitudinal direction of the stage unit (suction plate) (the direction perpendicular to the main scanning direction). Shall point to.

FIG. 1 is a perspective view showing the appearance of an ink jet printer. As shown in the figure, for example, a flatbed ink jet printer is used as the ink jet printer 1. The printing unit 4 is provided with a carriage 3 that reciprocates in the main scanning direction. The carriage 3 includes an inkjet head H that ejects ultraviolet curable ink droplets (hereinafter referred to as “ultraviolet curable ink”) onto a medium to be printed that is adsorbed and supported by an opposing stage unit 2 (adsorption plate). It is installed. The printing unit 4 is provided so as to reciprocate in the sub-scanning direction (X-axis direction) orthogonal to the main scanning direction (Y-axis direction) in which the carriage 3 reciprocates. In addition to paper such as plain paper, the medium includes resin sheets such as PLA (polylactic acid), PP (polypropylene), PET (polyethylene terephthalate), PC (polycarbonate), PMMA (polymethyl methacrylate), Various materials such as a woven fabric, a fabric sheet such as a nonwoven fabric, a metal sheet such as aluminum or stainless steel, or a synthetic sheet made of a composite material are included.

In the printing unit 4, first

ultraviolet curing lamps

5 a and 5 b (first ultraviolet irradiation means) which are mounted on the carriage 3 and are primarily cured by irradiating the ultraviolet curable ink immediately after being ejected from the inkjet head H with ultraviolet rays are the main components of the carriage 3. Provided on both sides in the scanning direction. The first ultraviolet curing

lamp units

5a and 5b are mounted with LED elements as light sources, and are provided corresponding to the printing ranges of the respective color heads provided in the inkjet head H.

Also, a printing unit cover 7 that is an exterior of the printing unit 4 is provided with a lamp housing cover 8 that protrudes in the sub-scanning direction and is detachable by external attachment. The lamp housing cover 8 is provided with a second ultraviolet curing lamp unit 9 (second ultraviolet irradiation means) for performing secondary curing by irradiating the ultraviolet cured ink that has been primarily cured with ultraviolet rays again. As will be described later, the first ultraviolet curing

lamp units

5a and 5b and the second ultraviolet curing lamp unit 9 are provided such that the distance from the medium can be adjusted. The lamp housing cover 8 is rotatably provided with an opening / closing member 11 that opens and closes an upper portion of the cover body 10.

The wavelength range of the first ultraviolet curing

lamp units

5a and 5b is 300 nm to 400 nm. In the inkjet printer 1, the printing unit 4 is moved from one side to the other side in the longitudinal direction of the stage unit 2 in the sub-scanning direction orthogonal to the main scanning direction every time the inkjet head H finishes printing for one line. Move towards.

2A and 2B, the lamp housing cover 8 is provided with an opening / closing member 11 that can be opened and closed with respect to a casing-like cover body 10. The opening / closing member 11 is formed of a resin material (acrylic resin or the like) that blocks ultraviolet rays and can be seen through the cover. With the opening / closing member 11 closed, the inside of the cover can be seen from the outside while blocking the ultraviolet rays. By opening the opening / closing member 11, the height of the second ultraviolet curing lamp unit 9 from the medium is adjusted as will be described later. Can be performed.

As shown in FIG. 3A, three

ultraviolet fluorescent lamps

9 a, 9 b, and 9 c are housed in the cover body 10 covered with the lamp housing cover 8 as the second ultraviolet curing lamp unit 9. The

ultraviolet fluorescent lamps

9 a, 9 b, 9 c are provided over a length equivalent to the scanning range of the carriage 3. In this embodiment, the number is three, but it may be smaller or larger. By using the

ultraviolet fluorescent lamps

9a, 9b, and 9c, it is cheaper than the LED, and even a single lamp can be irradiated over a wide range in the width direction of the medium. Thereby, the ultraviolet curable ink can be efficiently secondary-cured. In addition, since it is not necessary to provide a plurality of lamps in the main scanning direction, uneven irradiation hardly occurs.

In FIG. 4, the cover body 10 is a casing having openings at the top and bottom, and a lower opening 10a and an upper opening 10b (see FIG. 2B) are formed respectively. The upper opening 10 b is opened and closed by the lamp storage cover 8. The cover body 10 is disposed on the downstream side of the medium in the printing unit 4 with the lower opening 10a facing the stage 2 side. Specifically, the cover main body 10 is provided at the center front portion of the printing unit cover 7 so as to protrude from the side surface 7a of the printing unit cover 7 (see FIG. 1). The lateral width of the cover body 10 (width in the main scanning direction of the inkjet head H) is about 1800 mm, which is equal to or larger than the ultraviolet curable ink ejection region in the scanning direction of the inkjet head H, that is, the lateral width (1600 mm) of the stage unit 2. It has become. The vertical width (the width in the sub-scanning direction orthogonal to the main scanning direction) of the first

ultraviolet curing lamps

5a and 5b is about 200 mm. Corresponding to the configuration of the first

ultraviolet curing lamps

5a and 5b, the inkjet printer 1 has a printing area having a width of 1600 mm and a length of 2700 mm.

The ultraviolet fluorescent lamps 9a to 9c arranged in parallel in the cover body 10 extend substantially in parallel along the scanning direction (main scanning direction) of the inkjet head H. The ultraviolet fluorescent lamps 9a to 9c irradiate ultraviolet rays from the lower opening 10a of the cover body 10 toward the stage unit 2 side. The

ultraviolet fluorescent lamps

9a, 9b, and 9c are ultraviolet low-pressure mercury lamps that irradiate ultraviolet rays, and have a wavelength range of 350 nm to 400 nm (365 nm peak). That is, the wavelength range of the

ultraviolet fluorescent lamps

9a, 9b, 9c is different from the wavelength range of the first

ultraviolet curing lamps

5a, 5b. The length of the

ultraviolet fluorescent lamps

9a, 9b, 9c is about 1750 mm.

In FIG. 5, each of the

ultraviolet fluorescent lamps

9a, 9b, 9c is attached to each

lamp socket

12a, 12b, 12c, and each of the

lamp sockets

12a, 12b, 12c is connected to a

connector

13a, 13b, 13c. ing. The

connectors

13a, 13b, and 13c are connected to the power supply box 14 (see FIG. 1). The power supply box 14 is disposed on the upper portion of the printing unit 4 and includes a plurality of ballasts (inverter function built-in; not shown) for supplying a stable power to the

ultraviolet fluorescent lamps

9a, 9b, 9c. The

connectors

13a, 13b, and 13c are connected to ballasts, respectively. With such a configuration, in the second ultraviolet curing lamp 9, each of the

ultraviolet fluorescent lamps

9a, 9b, 9c can be turned on independently. Further, the

ultraviolet fluorescent lamps

9 a, 9 b, 9 c are independently controlled on / off by the control unit 15. Thereby, the necessary number of

ultraviolet fluorescent lamps

9a, 9b, 9c can be appropriately selected and turned on according to the required amount of ultraviolet irradiation. *

As described above, the on / off of the

ultraviolet fluorescent lamps

9a, 9b, 9c is controlled by the control unit 15. The control unit 15 (installed in the printer as firmware) also controls printing and the like in the ink jet printer 1. For example, a CPU (Central Processing Unit) or ROM
(Read Only Memory) and RAM (Random Access Memory). When the control unit 15 receives print data transmitted from, for example, a personal computer connected to the inkjet printer 1, the control unit 15 turns on the

ultraviolet fluorescent lamps

9a, 9b, and 9c. At this time, the control unit 15 sets the optimal number of

UV fluorescent lamps

9a, 9b, and 9c to be used for curing the ultraviolet curable ink based on the print data for printing on the medium. Specifically, the control unit 15 sets the number of lighting of the second ultraviolet curing lamp unit 9 based on a command related to ink ejection in the received print data (amount of ink droplets ejected from the nozzles). More specifically, for example, when the control unit 15 determines that the discharge amount of the ultraviolet curable ink necessary for printing is smaller than a predetermined amount in the print data, only a part of the ultraviolet fluorescent lamps 9a to 9c is turned on. If it is determined that the discharge amount of the ultraviolet curable ink necessary for printing is larger than the predetermined amount, all the ultraviolet fluorescent lamps 9a to 9c are turned on. Further, when the printing is completed, the control unit 15 turns off all the ultraviolet fluorescent lamps 9a to 9c.

FIG. 6 is a flowchart showing the operation of the inkjet printer. As shown in the figure, first, the control unit 15 determines whether or not print data is received in the inkjet printer 1 (step S01). When it is determined that the print data has been received, the control unit 15 sets the number of lighting of the second ultraviolet curing lamp unit 9 based on the print data, and any of the ultraviolet fluorescent lamps 9a to 9c is set based on this setting. Or all of them are turned on (step S02). On the other hand, if it is determined that print data has not been received, the process of step S01 is repeated.

Next, printing is executed based on the print data in the inkjet printer 1 (step S03). Specifically, in the inkjet printer 1, the ultraviolet curable ink ejected by the first ultraviolet

curable lamp units

5a and 5b is primarily cured while the ultraviolet curable ink is ejected onto the medium while moving the inkjet head H in the main scanning direction. Further, the ultraviolet curable ink first cured by the second ultraviolet curable lamp unit 9 is secondarily cured while moving the printing unit 4 in the sub-scanning direction, thereby printing an image on the medium. When the printing is completed and the area necessary for curing the ultraviolet curable ink is passed, the movement of the printing unit 4 is stopped (step S04). Finally, the ultraviolet fluorescent lamps 9a to 9c of the second ultraviolet curing lamp 9 are turned off by the control unit 15 (step S05).

As described above, in the inkjet printer 1, the ultraviolet curable ink discharged from the inkjet head H is provided in the first ultraviolet

curable lamp units

5 a and 5 b and the second ultraviolet curable lamp unit 9 provided in the carriage 3. Cured with ultraviolet fluorescent lamps 9a to 9c. With such a configuration, the ultraviolet curable ink ejected from the inkjet head H onto the medium is firstly cured by the first ultraviolet

curable lamp units

5 a and 5 b provided on the carriage 3. The primary cured ultraviolet curable ink is secondarily cured by the ultraviolet fluorescent lamps 9a to 9c of the second ultraviolet curable lamp unit 9 provided on the downstream side of the medium in the printing unit 4.

FIG. 7 is a diagram showing the irradiation amount of ultraviolet rays in the ink jet printer. In the same figure, the area | region shown by "A" has shown the irradiation amount of the ultraviolet-ray irradiated with the conventional ultraviolet curing lamp, and the area | region shown by "B" is 1st ultraviolet curing lamp unit 5a of this embodiment, The irradiation amount of the ultraviolet rays irradiated by 5b and the second ultraviolet curing lamp unit 9 is shown. The region “A” and the region “B” indicate the irradiation amount of ultraviolet rays necessary for printing the same print data at the same printing speed, and the irradiation amounts of ultraviolet rays are the same.

As shown in FIG. 7, in the conventional inkjet printer (area “A”), ultraviolet rays are irradiated only by the first

ultraviolet curing lamps

5a and 5b provided on both sides of the inkjet head, so that the ultraviolet curing ink is rapidly cured. In order to achieve this, ultraviolet rays with high illuminance are irradiated in a short time. In this case, since the ultraviolet curable ink discharged from the inkjet head H is cured before it spreads uniformly on the medium, streaks or the like may occur on the printing surface.

In contrast, in the inkjet printer 1 (region “B”) of the present embodiment, ultraviolet rays are irradiated by the first ultraviolet curing

lamp units

5a and 5b that perform primary curing and the second ultraviolet curing lamp unit 9 that performs secondary curing. Therefore, it is possible to irradiate ultraviolet rays having the same irradiation amount as the region “A” with low illuminance. As a result, the ultraviolet curable ink discharged onto the medium can be cured after it has spread uniformly. Therefore, it is possible to prevent the occurrence of streak-like patterns on the printing surface.

Incidentally, there are various media printed by the inkjet printer 1, and the sizes thereof are also different. Therefore, the discharge amount of the ultraviolet curable ink discharged from the inkjet head H onto the medium also varies depending on the size of the medium. Therefore, for example, even when the medium size is small and the discharge amount of the ultraviolet curable ink is small, it is not efficient to always turn on the second ultraviolet curable lamp unit 9. On the other hand, in the inkjet printer 1, the control unit 15 controls the number of the ultraviolet fluorescent lamps 9a to 9c that are turned on based on the print data for printing on the medium. Therefore, when the control unit 15 determines that, for example, the discharge amount of the ultraviolet curable ink is small in the print data, only a part of the ultraviolet fluorescent lamps 9a to 9c is turned on. Therefore, it is possible to efficiently irradiate ultraviolet rays according to the print data.

Next, an example of the height adjustment mechanism of the first ultraviolet curing

lamp units

5a and 5b and the second ultraviolet curing lamp unit 9 will be described.
There are three possible methods for adjusting the distance between the first ultraviolet curing

lamp units

5a and 5b and the medium. The first configuration is a configuration in which a Y-axis rail fixing member 21 (see FIG. 8) to which the Y-axis rail 20 on which the carriage 3 reciprocates is fixed is moved up and down, and the second configuration is the stage unit 2 on which the medium is placed. The configuration that moves up and down, and the third configuration, are configurations that raise and lower the carriage 3 itself.

In the present embodiment, the second ultraviolet curing lamp unit 9 is mounted on the printing unit cover 7 and is configured to be scanned in the sub-scanning direction together with the printing unit cover 7. For this reason, in the first configuration, the Y-axis rail 20 is moved up and down so that the printing unit cover 7 fixed to the Y-axis rail 20 also moves up and down at the same time, and the second ultraviolet curing lamp fixed to the printing unit cover 7 is obtained. The unit 9 also moves up and down. That is, in the first configuration, when the Y-axis rail 20 (see FIG. 8) is moved up and down in order to adjust the distance between the first ultraviolet curing

lamp units

5a and 5b, the second ultraviolet curing lamp unit 9 is also moved. It is configured to move up and down at the same time.

In addition, since the second configuration is a configuration in which the stage unit 2 itself on which the medium is placed is moved up and down, as the stage unit 2 moves up and down, the distance between the first ultraviolet curing

lamp units

5a and 5b and the medium, And both the space | interval of the 2nd ultraviolet curing lamp unit 9 and a medium changes simultaneously.

On the other hand, according to the third configuration, by adjusting the height of the carriage 3 with respect to the Y-axis rail fixing member 21, the distance between the first ultraviolet curing

lamp units

5a and 5b and the medium is independently adjusted. can do. Thus, since the carriage 3 can be moved up and down independently, only the carriage 3 can be moved up and down without moving the printing unit cover 7 up and down. Accordingly, the lamp housing cover 8 is assembled integrally with the printing unit cover 7, and the carriage 3 is moved up and down while maintaining the distance between the second ultraviolet curing lamp unit 9 housed in the lamp housing cover 8 and the medium. Thus, the distance between the first ultraviolet curing

lamp units

5a and 5b and the medium can be adjusted independently.

Further, in addition to the adjustment of the distance between the first ultraviolet curing

lamp units

5a and 5b and the medium, the distance between the second ultraviolet curing lamp unit 9 and the medium can be adjusted independently as described later. Further, the second ultraviolet curing lamp unit 9 can be moved in the sub-scanning direction together with the first ultraviolet curing

lamp units

5a and 5b by assembling the second ultraviolet curing lamp unit 9 integrally with the printing unit cover 7. It has become. When the printing unit 4 moves in the sub-scanning direction, the height of the Y-axis rail fixing member 21 is always constant. Therefore, only the carriage 3 can be moved up and down without moving the printing unit cover 7 up and down. Accordingly, the distance between the first ultraviolet curing

lamp units

5a and 5b and the medium can be adjusted independently while maintaining the distance between the second ultraviolet curing lamp unit 9 and the medium. Further, since the second ultraviolet curing lamp unit 9 is attached to the printing unit cover 7 so as to be adjustable in height, the second ultraviolet curing lamp unit 9 can also be independently adjusted with respect to the medium. .

As described above, since the printing unit 4 has the first ultraviolet curing

lamp units

5a and 5b and the second ultraviolet curing lamp unit 9, the printed matter can be printed in a matte tone or in a glossy manner. Print expression is possible. Specifically, the first ultraviolet curing

lamp units

5a and 5b are turned off, and printing is performed by ejecting ink onto the medium while scanning the inkjet head H in the main scanning direction with the second ultraviolet curing lamp unit 9 turned on. . As a result, the printed material becomes glossy. Further, the first ultraviolet curing

lamp units

5a and 5b are turned off, the ink is ejected onto the medium while the inkjet head H is scanned in the main scanning direction while the second ultraviolet curing lamp unit 9 is also turned off, and then printing is performed. Only the two ultraviolet curing lamp unit 9 is turned on, and the printing unit 4 is moved in the sub-scanning direction. As a result, the printed material becomes glossy. To perform matte printing, the first ultraviolet curing

lamp units

5a and 5b are turned on, and ink is ejected onto the medium while the inkjet head H is scanned in the main scanning direction while the second ultraviolet curing lamp unit 9 is turned on. To print.
In particular, in the present embodiment, the first ultraviolet irradiation means and the second ultraviolet irradiation means are provided such that the distance between the medium and the medium can be adjusted. Therefore, the curing conditions for the ultraviolet curable ink depending on the type of the medium and the printing conditions. Can be set in detail. That is, the amount of ultraviolet light from the two types of ultraviolet irradiation means with respect to the medium has a property that is inversely proportional to the square of the distance from each of the two types of ultraviolet irradiation means to the medium. For this reason, the printing conditions desired by the user can be realized by adjusting each of the two types of ultraviolet irradiation means independently to set the printing conditions more finely.

FIG. 8 illustrates the height adjustment mechanism of the first ultraviolet curing

lamp units

5a and 5b. Although not shown, the carriage 3 is mounted with an inkjet head H that ejects inks of M (magenta), Y (yellow), C (cyan), and K (black). First ultraviolet curing

lamp units

5a and 5b are fixed to both

side surfaces

3a and 3b of the carriage 3, respectively. Although not shown in the drawings, each of the first ultraviolet curing

lamp units

5a and 5b is assembled with a light source unit on which an LED chip is mounted, a cooling fin, a cooling fan, and the like for cooling the light source unit.

The back surface 3c of the carriage 3 is slidably connected to a Z-axis rail 17 via a Z-axis linear guide 16. The Z-axis rail 17 is fixed to the Y-axis scanning member 18. The Y-axis scanning member 18 is slidably connected to the Y-axis rail 20 via the Y-axis linear motion guide 19. The Y-axis rail 20 is fixed to a Y-axis rail fixing member 21 (Y bar). The Y-axis scanning member 18 is connected to a timing belt (not shown), and scans the carriage 3 along the Y-axis rail 20 in the main scanning direction by driving the belt.

Also, a Z-axis motor 18a is assembled to the Y-axis scanning member 18. The motor shaft of the Z-axis motor 18a is connected to the screw shaft 18b through a coupling. The screw shaft 18 b is screwed with a nut 3 d fixed to the back surface 3 c of the carriage 3. When the Z-axis motor 18a is rotationally driven, the carriage 3 linked to the screw shaft 18b via the nut 3d moves up and down along the Z-axis rail 17. Thereby, the space | interval of the inkjet head H and a medium and the space | interval of 1st ultraviolet curing

lamp unit

5a, 5b and a medium can be adjusted. The first ultraviolet curing

lamp units

5a and 5b can be arranged at intervals between the inkjet head H and the medium (carriage) by changing the mounting positions of the first ultraviolet curing

lamp units

5a and 5b on the side surfaces 3a and 3b of the carriage 3. (3) can be finely adjusted.

FIG. 9 illustrates the height adjustment mechanism of the second ultraviolet curing lamp unit 9.
Standing plates 22 are integrally fixed to both sides of the second ultraviolet curing lamp unit 9 housed in the cover body 10. Further, side covers 10c are erected on both sides of the upper opening 10b. On the side of the printing unit cover 7 of the side cover 10c, guide plates 23 bent in an L shape are fixed to both sides. Each guide plate 23 is formed with a guide rail 23a and an elongated screw hole 23b side by side in the Z-axis direction (height direction). The side cover 10c blocks leakage of ultraviolet rays from the ultraviolet fluorescent lamps 9a to 9c, and an upper end portion thereof serves as a receiving portion for the opening / closing member 11.

A part of the upright plate 22 is disposed so as to overlap the guide plate 23, and the guide portion 22a is slidably connected to the guide rail 23a. Further, a screw hole plate 22b having a screw hole 22c formed adjacent to the guide portion 22a is provided. The height of the upright plate 22 with respect to the guide plate 23 is obtained by screwing the fixing screw 24 through the screw hole 22c and the screw hole 23b in a state where the screw hole 22c of the screw hole plate 22b is overlapped with the screw hole 23b. The position is fixed.

When adjusting the height of the second ultraviolet curing lamp unit 9, the opening / closing member 11 of the lamp housing cover 8 is opened (see FIG. 2B), and the upright plate 22 is moved to the guide plate 23 while loosening the fixing screws 24 on both sides. The height is adjusted by sliding the guide rail 23a along the guide rail 23a to a predetermined height and then tightening the fixing screw 24 again. The height position with respect to the medium is determined by inserting a plate material having a predetermined thickness (not shown) between the second ultraviolet curing lamp unit 9 and the stage portion 2. Also, when replacing any or all of the ultraviolet fluorescent lamps 9a to 9c, the open / close member 11 of the lamp housing cover 8 is opened (see FIG. 2B) and the fixing screws 24 on both sides are loosened together with the upright plate 22. Maintenance is performed because the second ultraviolet curing lamp unit 9 is raised to the uppermost end and the fixing screw 24 is tightened to secure a sufficient space between the lower opening 10a of the cover body 10 and the stage portion 2 and then the replacement work can be performed. Work becomes easier.

As described above, the first

ultraviolet lamp units

5a and 5b and the second ultraviolet lamp unit 9 adjust the curing conditions of the ultraviolet curable ink according to the type of the medium and the printing conditions by adjusting the height from the medium. Can be set finely. Therefore, different textures depending on the printing conditions, such as curing immediately after ink droplets have landed on the medium to give a matte tone, or curing after ink droplets have landed on the medium with a predetermined interval (see the timing of leveling) To make it glossy. Moreover, the request | requirement of exposure prevention of the ultraviolet-ray generated by the space | interval of the 1st

ultraviolet lamp unit

5a, 5b or the 2nd ultraviolet lamp unit 9 and a medium can also be satisfy | filled.

In particular, by attaching a lamp housing cover 8 housing the second ultraviolet curing lamp unit 9 to the printing unit cover 7, the ultraviolet fluorescent lamps 9a to 9c are appropriately selected and turned on according to the necessary ultraviolet irradiation amount. be able to. Therefore, it is possible to efficiently irradiate ultraviolet rays according to the discharge amount of the ultraviolet curable ink discharged onto the medium. Further, as shown in FIGS. 3B to 3D, the printing unit 4 is moved in the sub-scanning direction (longitudinal direction of the stage unit 2) without scanning the carriage 3 (first ultraviolet curing

lamp units

5a and 5b; see FIG. 1). By turning on and off only the second ultraviolet curing lamp unit 9 (ultraviolet fluorescent lamps 9a to 9c) while being moved, the ink can be efficiently cured according to the ink discharge amount.

As described above, in the inkjet printer 1, the ultraviolet curable ink can be quickly cured, and the curing conditions of the ultraviolet curable ink can be set finely according to the type of the medium and the printing conditions. For example, in a low-viscosity ink such as clear ink that has a remarkable matte and glossy printing effect, the ink is ejected from the inkjet head H while the first ultraviolet curing

lamp units

5a and 5b are turned off. The ink is discharged from the inkjet head H by turning on the second ultraviolet curing lamp unit 9 or with the first ultraviolet curing

lamp units

5a and 5b and the second ultraviolet curing lamp unit 9 turned off, and after the printing is finished, the second ultraviolet curing lamp unit 9 is turned on. Printing is performed by scanning the printing unit 4 in the sub-scanning direction with the ultraviolet curing lamp unit 9 turned on. At this time, since the printing unit 4 does not scan the carriage 3 in the main scanning direction and does not perform an intermittent operation, the printing quality can be improved.

Further, each of the ultraviolet fluorescent lamps 9a to 9c extends substantially in parallel along the scanning direction of the inkjet head H, and the length of the ultraviolet fluorescent lamps 9a to 9c is the ink in the scanning direction of the jet head H. It becomes more than the discharge area. According to this configuration, the ultraviolet fluorescent lamps 9a to 9c of the second ultraviolet curing lamp unit 9 can reliably irradiate ultraviolet rays over the entire ejection area of the ultraviolet curing ink ejected from the inkjet head H.

Further, the wavelength range of the ultraviolet fluorescent lamps 9a to 9c is different from the wavelength range of the first ultraviolet curing

lamp units

5a and 5b. As described above, by changing the wavelength range of the ultraviolet rays irradiated to the ultraviolet curable ink between the primary curing and the secondary curing, it is possible to perform printing with good print quality.

In the above embodiment, the control unit 15 sets the number of the UV lamps 9a to 9c to be turned on based on the print data and lights the corresponding UV lamps 9a to 9c. However, the lighting control of the UV lamps 9a to 9c is performed. The printing may be performed by a printer who performs printing.

In the above-described embodiment, three ultraviolet fluorescent lamps 9a to 9c are provided in the second ultraviolet curing lamp unit 9, but the number of ultraviolet fluorescent lamps is not limited to this.

Further, in the above embodiment, the second ultraviolet curing lamp unit 9 is externally attached to the flood bed type inkjet printer 1, but the inkjet printer on which the second ultraviolet curing lamp unit 9 is mounted is limited to the flood bed type. It may be a grid rolling type or the like.

In the above embodiment, the control unit 15 controls the turning on and off of the ultraviolet fluorescent lamps 9a to 9c. However, the control unit 15 adjusts the illuminance of ultraviolet rays in the ultraviolet fluorescent lamps 9a to 9c by controlling the driving frequency. You may go.

In the above embodiment, the control unit 15 sets the number of the ultraviolet lamps 9a to 9c to be turned on based on the print data, and turns on the ultraviolet fluorescent lamps 9a to 9c. The lighting positions of the ultraviolet fluorescent lamps 9a to 9c may be controlled based on the above. Specifically, the control unit 15 sets the lighting positions of the ultraviolet fluorescent lamps 9a to 9c based on a command related to the type of ink in the received print data. More specifically, for example, when the viscosity of the ultraviolet curable ink is high in print data, that is, when the speed of spreading when discharged onto the medium is low, the control unit 15 causes the second ultraviolet curable lamp unit 9 to print the printing unit 4. If, for example, the ultraviolet lamp 9a arranged at the farthest position is turned on and the viscosity of the ultraviolet curable ink is low, that is, the speed of spreading when ejected onto the medium is high, the second ultraviolet curable lamp unit 9 performs printing. For example, an ultraviolet lamp 9c arranged at a position closest to the unit 4 is turned on. In this way, by changing the ultraviolet lamps 9a to 9c to be turned on according to the viscosity of the ultraviolet curable ink, that is, the spread of the ultraviolet curable ink on the medium, the time from the primary curing to the secondary curing can be changed. Each of them can be changed according to the characteristics.

That is, in the case of a UV-curable ink having a high viscosity, the UV lamp 9a disposed at the position farthest from the first UV-curing

lamp units

5a and 5b and the printing unit 4 is used, and from the primary curing to the secondary curing. By extending the time in between, the ultraviolet curable ink can be cured after sufficiently spreading on the medium. As a result, the print quality can be improved.

Further, in the case of UV curable ink having a low viscosity, the UV lamp 9c is used which is disposed at a position closest to the first UV

curable lamp units

5a and 5b and the printing unit 4, and the time from primary curing to secondary curing is increased. By shortening the length, the ultraviolet curable ink on the medium can be instantaneously cured. As a result, it is possible to improve the printing speed. Note that the above-described control can also cope with a difference in curing speed of the ultraviolet curable ink.

In the above-described embodiment, the three ultraviolet fluorescent lamps 9a to 9c that extend in the scanning direction of the inkjet head H and have a length (about 1750 mm) longer than the ultraviolet curable ink ejection region in the scanning direction are used. However, the type and arrangement of the ultraviolet lamp are not limited to this. For example, the ultraviolet fluorescent lamps 9a to 9c may have a length that is ½ of the discharge area of the ultraviolet ink in the scanning direction of the inkjet head H. For example, three such ultraviolet fluorescent lamps 9a to 9c are arranged in parallel in the sub-scanning direction around the central portion of the printing unit 4 in the lamp housing cover 8, for example, six in total. In such a configuration, the control unit 15 turns on only three ultraviolet lamps arranged on one side, for example, across the center of the printing unit 4 based on the print area in the print data. Thereby, an ultraviolet-ray can be efficiently irradiated according to a printing area | region. Of course, the ultraviolet fluorescent lamp may have a length of 1/3 or 1/4 as well as 1/2 the length of the ultraviolet ink ejection region. The point is that the second ultraviolet curing lamp unit 9 may be configured to irradiate ultraviolet rays over the entire discharge area of the ultraviolet curing ink in the main scanning direction.

Further, the height adjusting mechanism of the first ultraviolet curing

lamp units

5a and 5b and the second ultraviolet curing lamp unit 9 is not limited to the embodiment. For example, although the first ultraviolet curing

lamp units

5a and 5b move the carriage 3 up and down through the screw shaft by driving the motor, it may be moved up and down by meshing the rack and the pinion. It is also possible to use another drive source such as a solenoid. In addition, the second ultraviolet curing lamp unit 9 is manually lifted and lowered by the operator by loosening the fixing screw 24, but may be lifted and lowered using a drive source (motor, cylinder, solenoid, etc.).

Claims

A printing unit that is mounted on a carriage that reciprocates in the main scanning direction, includes an inkjet head that discharges ultraviolet curable ink onto a facing medium, and is capable of reciprocating in the sub-scanning direction perpendicular to the main scanning direction in which the carriage reciprocates. An inkjet printer comprising:
The printing unit is mounted on the carriage with first ultraviolet irradiation means for irradiating the ultraviolet curable ink immediately after being ejected from the inkjet head with ultraviolet rays for primary curing, and the primary cured ultraviolet curable ink is again irradiated with ultraviolet rays. An ink jet printer comprising: a second ultraviolet irradiation means for secondary curing, wherein the first ultraviolet irradiation means and the second ultraviolet irradiation means are provided such that the distance between the medium and the medium can be adjusted. .
2. The ink jet printer according to claim 1, wherein the second ultraviolet irradiation means is an ultraviolet fluorescent lamp unit.
The inkjet printer according to claim 1, wherein the second ultraviolet irradiation means is provided with an ultraviolet fluorescent lamp unit over a length equivalent to a main scanning range of the carriage.
The inkjet printer according to claim 1, wherein a plurality of ultraviolet fluorescent lamps are provided in the sub-scanning direction as the second ultraviolet irradiation means, and each ultraviolet fluorescent lamp is independently controlled on and off.
The printing unit cover which is an exterior of the printing unit is characterized in that a lamp housing cover for housing the ultraviolet fluorescent lamp unit is formed to protrude in the sub-scanning direction so as to cover the movement range of the carriage in the main scanning direction. The ink jet printer according to claim 1.
In the printing unit cover that is an exterior of the printing unit, a lamp housing cover that houses the ultraviolet fluorescent lamp unit is formed to protrude in the sub-scanning direction so as to cover the movement range of the carriage in the main scanning direction. 2. An ink jet printer according to claim 1, wherein an opening and closing member for opening and closing the upper part is rotatably provided, and the opening and closing member is made of a resin material that blocks ultraviolet rays and can be seen through the cover. .