JP2008188826A - Three-dimensional printing method and inkjet printing apparatus used therefor - Google Patents

Abstract

A three-dimensional shape having excellent fixing properties can be formed on the surface of a general-purpose substrate, and the three-dimensional shape and a non-three-dimensional print can be printed without causing a deviation or the three-dimensional shape can be shifted. The present invention provides a three-dimensional printing method that can be colored without occurrence and an ink jet printing apparatus that is suitable for carrying out the three-dimensional printing method.
SOLUTION: Volumes V ₁ and V _{2 of} each ejected ink drop are expressed by the formula (1):
V ₁ ≧ V ₂ × 10 (1)
And curable ink is supplied from the first inkjet head 11 using the inkjet printing apparatus 1 including the first and second inkjet heads 11 and 12 having V _{2 of 3} to 20 pl. It is ejected as droplets to form a three-dimensional shape on the surface of the printing medium, and colored ink is ejected as ink droplets from the second inkjet head to print or color the surface.
[Selection] Figure 2

Description

  The present invention relates to a three-dimensional printing method for performing three-dimensional printing on the surface of a planar printing medium such as paper or a resin film, and an ink jet printing apparatus used for carrying out the three-dimensional printing method.

  An inkjet printing method for ejecting fine ink droplets from an inkjet head to reach the surface of a printing medium such as paper or a resin film and printing arbitrary characters or figures on the surface is, for example, a screen printing method. Unlike other printing methods such as a gravure printing method, electronically produced image data can be directly printed on the surface without performing plate making in advance, and multicolor printing is also possible. It is widely used as a simple printing method. Recently, various studies have been made to utilize the above-described advantages in order to use the inkjet printing method in various fields. One of them is a three-dimensional printing method in which three-dimensional printing is performed on the surface of a printing medium by an ink jet printing method, that is, a three-dimensional shape such as Braille is formed.

  For example, Patent Document 1 discloses that ink containing thermally foamable particles that are foamed by heating is printed on the surface of a printing medium by an inkjet printing method, and then heated to foam the thermally foamable particles. A three-dimensional printing method for forming a three-dimensional shape such as Braille is described. Further, in Patent Document 2, normal ink is printed on the surface of a printing medium by an ink jet printing method, and then the thermally foamable particles are sprayed and selectively fixed to a printed portion before the ink dries. Then, a three-dimensional printing method is described in which a three-dimensional shape such as Braille is formed by heating and foaming the thermally foamable particles. However, in each of the three-dimensional printing methods described in Patent Documents 1 and 2, the solid shape of the three-dimensional shape made of a foam of thermally foamable particles has insufficient fixability on the surface of the printing material, and the three-dimensional shape is There is a problem that it tends to fall off from the surface.

  In Patent Document 3, a printing sheet made of a compressed sheet of a sponge-like tissue body that expands due to moisture absorption is used as a printing medium, and water-based ink is printed by an inkjet printing method. A three-dimensional printing method is described in which a three-dimensional shape is formed by selectively expanding only at a printing portion. Further, in Patent Document 4, roll paper having thermal expansibility that expands by heating is used as a printing medium, and the surface of the printing medium is heated by a thermal head and is selectively expanded by a thermal head. A three-dimensional printing method is described in which a three-dimensional shape is formed and characters and the like are printed on the surface by an inkjet printing method. However, each of the three-dimensional printing methods described in Patent Documents 3 and 4 has a problem that versatility is low because the special printing medium described above is required.

  In Patent Documents 5 and 6, ink that has photocurability that is cured by irradiation with light such as ultraviolet rays and that has low wettability with respect to the surface of the printing medium is printed on the surface of the printing medium by an inkjet printing method. Subsequently, a three-dimensional printing method is described in which a three-dimensional shape such as braille is formed by curing by light irradiation. According to the three-dimensional printing method, by setting the wettability of the ink to be used to the surface of the printing medium to be low, the ink droplets discharged from the inkjet head and reaching the surface of the printing body are It is possible to grow in the thickness direction and the surface direction by supplying a plurality of ink droplets while maintaining the droplet shape without spreading on the surface. Therefore, by irradiating the grown droplets with light to cure the ink, it is possible to form a three-dimensional shape having a sufficient thickness and excellent fixability to the surface of the printing medium.

  However, in the three-dimensional printing method described in Patent Documents 5 and 6, if the three-dimensional shape to be formed changes according to the surface state of the printing medium and the surface state of the printing medium is different, the same ink is used. However, there is a problem that the same three-dimensional shape cannot be formed. That is, as the wettability of the ink with respect to the surface of the printing medium decreases, the droplets tend to spread in the surface direction and become a crushed shape in the thickness direction. Even if the surface is made of the same material or a surface made of the same material, a difference occurs in the three-dimensional shape that can be formed depending on the surface shape (mat surface or gloss surface).

Furthermore, in the three-dimensional printing methods described in Patent Documents 1 to 3 and Patent Documents 5 and 6, a deviation occurs between the three-dimensional shape described above and non-three-dimensional printing such as characters on the surface of the printing medium. There is also a problem that printing cannot be performed without any problem, and the formed three-dimensional shape cannot be colored without causing a shift.
JP 7-61047 A JP 2001-353907 A Japanese Patent Laid-Open No. 10-258506 JP 2003-182158 A JP 2000-37943 A JP 2000-38531 A

  An object of the present invention is to form a three-dimensional shape with excellent fixability on the surface of a general-purpose printing medium such as paper or a resin film, and causes a deviation between the three-dimensional shape and a non-three-dimensional print. An object of the present invention is to provide a three-dimensional printing method capable of printing without forming or coloring a formed three-dimensional shape without causing a shift, and an ink jet printing apparatus suitable for performing the three-dimensional printing method. .

In the three-dimensional printing method of the present invention, a curable ink is ejected as ink droplets, and a first ink jet head for reaching the surface of a planar printing medium, and colored inks are ejected as ink droplets. A second inkjet head for reaching the surface, and a curing means for curing or precuring the curable ink reaching the surface, and from the first inkjet head The volume V ₁ [pl] per droplet of the ejected ink droplet and the volume V ₂ [pl] per droplet of the ink droplet ejected from the second inkjet head are expressed by the following equation (1):
V ₁ ≧ V ₂ × 10 (1)
And curable ink is ejected as ink droplets from the first ink jet head using an ink jet printing apparatus having V _{2 of 3} to 20 pl, and reaches the surface of the planar printing medium. A step of forming a three-dimensional shape or a precursor thereof on the surface by curing or pre-curing by a curing means, and discharging the colored ink as ink droplets from the second inkjet head, Three-dimensional printing is performed on the surface through a step of performing at least one of printing and coloring.

  According to the three-dimensional printing method of the present invention, the curable ink discharged from the first inkjet head and reaching the surface of a general-purpose printing medium such as paper or resin film is cured by the curing means. Thus, a three-dimensional shape having excellent fixability or a precursor thereof can be formed on the surface of the printing material. In addition, a non-three-dimensional print is shifted from the three-dimensional shape on the surface of the substrate by colored ink discharged from the second inkjet head that can be operated in conjunction with the first inkjet head. It is also possible to print without occurrence or to color a three-dimensional shape without causing a shift.

Moreover, according to the three-dimensional printing method of the present invention, the volume V ₂ per droplet of the ink droplets made of colored ink discharged from the second inkjet head is in the range of ₃ to 20 pl. The image quality of printing and three-dimensional coloring can be maintained at a high level, and the volume V ₁ per droplet of ink droplets made of curable ink discharged from the first inkjet head because you are more than 10 times the volume V _2, on the surface of the printing material, the three-dimensional shape having a sufficient thickness may be more short time formation.

  In the three-dimensional printing method of the present invention, the curable ink is ejected as ink droplets from the first ink jet head to reach the surface of the planar printing medium, and is cured by a curing means, It is preferable to form a three-dimensional shape on the surface and then discharge at least one of printing on the surface and coloring by discharging colored ink as ink droplets from the second inkjet head. Has an advantage that three-dimensional printing can be formed only by processing in the ink jet printing apparatus.

  In the three-dimensional printing method of the present invention, as the curable ink, an ink containing thermally foamable particles that are foamed by heating is used, and the ink is ejected as ink droplets from the first inkjet head to form a planar shape. The surface of the substrate to be printed is preliminarily cured by a curing means to form a three-dimensional precursor on the surface, and then the colored ink is ejected as ink droplets from the second inkjet head. After performing printing on the surface and / or coloring, the printed material may be heated to foam the thermally foamable particles and the ink may be cured to form a three-dimensional shape.

  In that case, after the thermally foamable particles in the precursor are foamed, the surface of the substantially planar printed material is printed or colored with colored ink, and then the thermally foamable particles are foamed. Since it is possible to form a three-dimensional shape, the effect of printing a non-three-dimensional print on the surface of the substrate without causing a deviation from the three-dimensional shape, or coloring the three-dimensional shape without causing a deviation, This can be further improved. In addition, since the three-dimensional shape formed on the surface can be made sufficiently thick by foaming the thermally foamable particles, the consumption of curable ink is reduced and the curable property is reduced. The time required to form a three-dimensional shape by printing the ink can be further shortened.

  In addition, as the curable ink containing thermally foamable particles, a photocurable ink is used, and the ink is made to reach the surface of the planar printing medium by light irradiation from the light irradiation unit as the curing unit. In the next step, the thermal foamable particles are prevented from foaming at the time of preliminary curing, and the thermal foamable particles are fixed on the surface of the printing medium by the preliminary curing. Since the thermally foamable particles can be foamed, a three-dimensional shape made of a foam of the thermally foamable particles can be more firmly fixed on the surface.

  According to the three-dimensional printing method of the present invention, it is possible to form braille on the surface of a planar printing medium using a curable ink and to form a print using a colored ink. Further, a three-dimensional shape is formed on the surface of the planar printing material using a curable transparent ink, and then the surface of the three-dimensional shape is coated with a white ink, and then the colored ink is applied. It is also possible to color the formed three-dimensional shape to form, for example, an oil painting-style three-dimensional painting.

The ink jet printing apparatus of the present invention causes a curable ink to be ejected as ink droplets, and causes a first ink jet head to reach the surface of a planar printing medium, and ejects colored ink as ink droplets. A second inkjet head for reaching the surface, and a curing means for curing or precuring the curable ink reaching the surface, and from the first inkjet head The volume V ₁ [pl] per droplet of the ejected ink droplet and the volume V ₂ [pl] per droplet of the ink droplet ejected from the second inkjet head are expressed by the following equation (1):
V ₁ ≧ V ₂ × 10 (1)
And V ₂ is 3 to ₂₀ pl.

  According to the inkjet printing apparatus of the present invention, the three-dimensional printing method of the present invention can be performed to form a three-dimensional shape with excellent fixability on the surface of a printing medium such as paper or a resin film, It is possible to print the three-dimensional shape and the non-three-dimensional print without causing a shift, or to color the formed three-dimensional shape without causing a shift.

  According to the present invention, a three-dimensional shape having excellent fixability can be formed on the surface of a general-purpose substrate such as paper or a resin film, and the three-dimensional shape and a non-three-dimensional print are displaced. It is possible to provide a three-dimensional printing method capable of printing without forming or coloring a formed three-dimensional shape without causing a shift, and an ink jet printing apparatus suitable for performing the three-dimensional printing method. .

<Inkjet printer>
FIG. 1 is a schematic cross-sectional view in the paper feed direction showing the internal structure of an example of an embodiment of an ink jet printing apparatus of the present invention used for carrying out the three-dimensional printing method of the present invention. FIG. 2 is a schematic cross-sectional view in the direction orthogonal to the paper feed direction, showing the internal structure of the ink jet printing apparatus of the above example.

  With reference to both the drawings, the inkjet printing apparatus 1 of this example protrudes obliquely upward from the left surface of the housing 2 and the housing 2 on the left surface in FIG. 1 (the back surface of the inkjet printing device 1). The tray 3 for supplying a printing medium (not shown) such as paper or a resin film attached to the right side of the casing 2 in FIG. 1 (front side of the inkjet printing apparatus 1) , And a tray 4 for receiving a printing medium (not shown) discharged after completion of printing.

  In addition, a plurality of rollers 5 to 8 and a guide member 9 transport the substrate to be printed supplied from the tray 3 in the paper feed direction indicated by a solid arrow in FIG. In addition, a conveyance path 10 for the printing medium to be discharged to the tray 4 is configured, and curable ink is ejected in the middle of the conveyance path 10 so that the conveyance path 10 is in the middle of conveyance. A first inkjet head 11 for forming a three-dimensional shape or a precursor thereof on the surface of the printing body, and a second inkjet head for printing or coloring the surface by discharging colored ink 12 and a curing means 13 for curing or pre-curing the curable ink that has reached the surface.

An ink cartridge 14 for supplying curable ink to the first inkjet head 11 is connected to the first inkjet head 11, and the second inkjet head 12 is connected to the second inkjet head 12. An ink cartridge 15 for supplying colored ink to the inkjet head 12 is connected.
The rollers 5 and 6 are registration rollers for sending out the printing medium accommodated on the tray 3 one by one to the conveyance path 10. The rollers 7 and 8 are set in advance when three-dimensional printing is performed by ejecting ink from the first and second inkjet heads 11 and 12 to the surface of the printing material sent out from the tray 3, respectively. In accordance with the predetermined printing pitch, the paper feeding roller is configured to convey the printing medium at a predetermined pitch in the paper feeding direction indicated by the solid line arrow.

  The first and second inkjet heads 11 and 12, the ink cartridges 14 and 15 connected to the respective inkjet heads 11 and 12, and the curing unit 13 are integrally mounted on a carrier (not shown). 2, as indicated by white arrows in FIG. 2, they are disposed so as to be capable of reciprocating in the width direction of the substrate to be printed, which intersects the paper feeding direction. Each unit stands by at the stand-by position shown in FIG. 2 during standby when 3D printing is not performed. Then, the printing medium is conveyed on the conveyance path 10 at a predetermined pitch by the paper feed rollers 7 and 8, and the three-dimensional printing is performed while reciprocating the carrier in the width direction in accordance with the conveyance. Done.

  That is, a step of discharging a curable ink from the first inkjet head 11 to reach the surface of the printing medium and curing it by the curing means 13 to form a three-dimensional shape; By performing the printing and coloring process by discharging the colored ink continuously in accordance with the reciprocation of the carrier, three-dimensional printing can be performed on the surface. Specifically, for example, the carrier is reciprocated in a state in which the paper feed by the paper feed rollers 7 and 8 is stopped to form a three-dimensional shape in an area of a certain width on the surface of the printing medium, and then the stop is performed. By performing reciprocating movement of the carrier while maintaining the state and performing printing and coloring on the surface of the surface of the fixed width having the three-dimensional shape alternately with paper feeding, the substrate to be printed Three-dimensional printing can be performed on the entire surface of the sheet.

As described above, the first and second inkjet heads 11 and 12 have a volume V ₁ [pl] per droplet of the curable ink droplets ejected from the first inkjet head 11. The volume V ₂ [pl] of each drop of the colored ink ejected from the second inkjet head 12 is expressed by the following equation (1):
V ₁ ≧ V ₂ × 10 (1)
And V ₂ needs to be set to ₃ to 20 pl.

When the volume V ₂ per droplet of the colored ink droplets discharged from the second inkjet head 12 exceeds the range, the ink droplets are formed on the surface of the printing medium by the ink droplets. This is because the image quality of printing and coloring cannot be maintained at a high level. If the volume V ₂ is less than the above range, it is necessary to eject a larger number of ink droplets from the second inkjet head 12 in order to perform printing or coloring with a sufficient density, and printing is performed on the surface of the printing medium. This is because the time required for coloring is increased. Both of these problems are solved satisfactorily, and printing and coloring are performed on the surface of the printing material while maintaining the image quality of printing and coloring formed on the surface of the printing material at a high level. In consideration of shortening the time required for the ink droplets as much as possible, the volume V ₂ per droplet of the ink droplets of the colored ink ejected from the second inkjet head 12 is 3 to 10 pl even within the above range. Is preferred.

In addition, if the volume V ₁ of the ink droplets of the curable ink discharged from the first inkjet head 11 is less than 10 times the volume V ₂ , the surface of the printing medium is sufficient. This is because a three-dimensional shape having a thickness cannot be formed in a short time. Note that the volume V ₁ per droplet of the curable ink droplets ejected from the first inkjet head 11 is within the above range in consideration of improving the definition and reproducibility of the three-dimensional shape. However, it is preferably 500 pl or less, and more preferably 30 to 100 pl, considering that the above effect and the effect of forming a three-dimensional shape in a shorter time are compatible.

  Each of the first and second inkjet heads 11 and 12 is a so-called multi-nozzle type including a plurality of nozzles for ejecting ink droplets and a mechanism for ejecting ink droplets from each nozzle. Is preferable. Thereby, in the 1st inkjet head 11, it becomes possible to form the said solid shape in a shorter time, improving the precision of the solid shape formed on the surface of a to-be-printed body, reproducibility, etc. Further, the second inkjet head 12 shortens the time required for printing and coloring on the surface of the printing medium while maintaining the image quality of printing and coloring formed on the surface of the printing medium at a high level. can do.

Further, the second inkjet head 12 is configured to individually add, for example, four colors of cyan, magenta, yellow, and black, or more, colored inks in order to support multicolor printing. It is preferable that the ink can be discharged. On the other hand, only one kind of curable ink is ejected from the first inkjet head 11.
However, for example, when using a photocurable ink to form a three-dimensional shape that is the basis of an oil painting-style three-dimensional painting, a transparent, photocurable ink that does not contain a pigment is most likely to undergo a curing reaction. Therefore, it is preferable to form a three-dimensional shape having the above-mentioned laminated structure for the purpose of providing a concealing property and adjusting the ground color in addition to forming a three-dimensional shape with the transparent ink. In this case, it is preferable that the first inkjet head 11 can eject the two types of inks individually as ink droplets.

  In the first and second ink jet heads 11 and 12, as a mechanism for ejecting ink droplets from the nozzles, for example, a thermal method [thermal jet (registered trademark) method, bubble jet (registered trademark) method], piezo method, or the like. Any of various conventionally known so-called on-demand mechanisms can be employed. As the curing means 13, various means can be employed according to the curing mechanism of the curable ink. For example, when the curable ink is a thermosetting ink, examples of the curing means 13 include a heater. In addition, when the curable ink is a photocurable ink that undergoes a curing reaction upon irradiation with light such as ultraviolet rays, a lamp capable of irradiating the surface of the printing medium with light such as ultraviolet rays as the curing means 13. And light sources such as semiconductor lasers and LEDs. For example, examples of the ultraviolet light source include a high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, a cold cathode tube, a semiconductor ultraviolet laser, and an ultraviolet LED.

As a suitable example of the three-dimensional printing method of the present invention using the inkjet printing apparatus 1, one of the following methods may be mentioned.
<3D printing method (I)>
The curable ink is ejected as ink droplets from the first inkjet head 11 to reach the surface of the planar printing medium and is cured by the curing means 13 to form a three-dimensional shape on the surface. Then, a three-dimensional printing method in which colored ink is ejected as ink droplets from the second inkjet head 12 to perform at least one of printing on the surface and coloring.

<3D printing method (II)>
As the curable ink, an ink containing thermally foamable particles that are foamed by heating is used, and the ink is ejected as ink droplets from the first inkjet head 11 so as to reach the surface of the planar printing medium. , Pre-curing by the curing means 13 to form a three-dimensional precursor on the surface, and then discharging the colored ink as ink droplets from the second inkjet head 12 to print on the surface; And a method of three-dimensional printing in which, after performing at least one of coloring, the printed material is heated to foam the thermally foamable particles and the ink is cured to form a three-dimensional shape.

According to the three-dimensional printing method (I), there is an advantage that three-dimensional printing can be formed only by processing in the inkjet printing apparatus 1. In the three-dimensional printing method (I), the curing reaction may be completed by, for example, heating the printed substrate discharged from the inkjet printing apparatus 1.
In addition, according to the three-dimensional printing method (II), after foaming the thermally foamable particles in the precursor, after performing printing or coloring with colored ink on the surface of the substantially planar substrate, Since the three-dimensional shape can be formed by foaming the thermally foamable particles, a non-three-dimensional print can be printed on the surface of the printing body without causing a deviation from the three-dimensional shape, or the three-dimensional shape can be produced without causing a deviation. The effect of coloring can be further improved. In addition, the solid shape formed on the surface has a sufficient thickness by foaming the thermally foamable particles by heating the printed material discharged from the inkjet printer 1 or the like. Therefore, the consumption of the curable ink can be reduced, and the time required to form the three-dimensional shape by printing the curable ink can be further shortened.

  Further, as the curable ink containing thermally foamable particles, a photocurable ink is used, and the surface of the planar printing medium is reached by light irradiation from the light irradiation unit as the curing unit 13. When the ink is pre-cured, in the next process, the heat-foamable particles are prevented from foaming during the pre-curing and the heat-foamable particles are fixed on the surface of the printing medium by the pre-curing. Since the thermally foamable particles can be foamed, the three-dimensional shape made of the foam of the thermally foamable particles can be more firmly fixed on the surface.

《Curable ink》
As the curable ink ejected from the first inkjet head 11, any of various inks that have thermosetting properties, photocuring properties, and the like and can be printed by inkjet printing can be used. As the curable ink, for example, a resin precursor such as a monomer, an oligomer, or a prepolymer having radical polymerizability, cation polymerizability, and the like, and a polymerization reaction of the resin precursor are started to be printed. And an ink containing a polymerization initiator (thermal polymerization initiator, photopolymerization initiator) or the like for curing the ink reaching the surface by heat or light from the curing means 13.

  As described above, the curable ink that is discharged from the first inkjet head 11 to form a three-dimensional shape is preferably a transparent ink that does not contain a pigment or the like and easily undergoes a curing reaction. The transparent ink has a temperature of 25 ° C. in consideration of forming a three-dimensional shape having a sufficient thickness on the surface of the substrate to be printed in a shorter time and discharging the nozzles of the first inkjet head 11 satisfactorily. The viscosity in is preferably 0.02 to 0.03 Pa · s.

  The transparent ink may contain thermally expandable particles that are foamed by heating. Examples of the heat-foamable particles include those made of a copolymer of vinylidene chloride and acrylonitrile and the like, in which a low-boiling hydrocarbon or the like is enclosed in a shell having thermosoftening properties. In consideration of good discharge from the nozzles of the inkjet head 11, the particle size is preferably 30 μm or less. In addition, considering that the thermally foamable particles are foamed in a temperature range that does not affect the printed material or the like, during the preliminary curing of the photocurable ink, for example, by light irradiation, etc. It is preferable that the softening temperature of the shell which defines the foaming start temperature is 70 to 150 ° C.

  Examples of the thermally foamable particles include Matsumoto Microsphere (registered trademark) F-30 manufactured by Matsumoto Yushi Seiyaku Co., Ltd. (particle size: 10 to 20 μm, true specific gravity: 1.13, pore expansion ratio: about 70 times, shell softening temperature: 80 to 85 ° C., F-50 [particle size: 10 to 20 μm, true specific gravity: 1.02, pore expansion ratio: about 20 times, shell softening temperature: 100 to 105 ° C. F-80S [particle diameter: 20-30 μm, true specific gravity: 1.05, pore expansion ratio: about 60 times, shell softening temperature: 135-140 ° C.], F-85 [particle diameter: 20-30 μm , True specific gravity: 1.05, pore expansion ratio: about 60 times, shell softening temperature: 140-145 ° C.] and the like.

  The content of the heat-expandable particles is preferably 1 to 10% by mass of the total amount of the components that form a solid shape after curing in the ink. If the content is less than the above range, the effect of forming a three-dimensional shape having a sufficient thickness cannot be obtained sufficiently by the small amount of ink described above by containing thermally foamable particles in the ink. On the contrary, when the above range is exceeded, the amount of ink for fixing the foam of thermally foamable particles on the surface of the printing medium is relatively short, The resulting three-dimensional shape may not be satisfactorily fixed on the surface.

  In addition, when the content exceeds the above range, a large amount of thermally foamable particles are clogged in the nozzles of the first inkjet head 11, or the viscosity of the ink exceeds the preferred range described above. Since the ink tends to be trapped, there is a possibility that the ink cannot be ejected stably and satisfactorily from the nozzle. When the heat-expandable particles are contained in the transparent ink, a predetermined amount of the heat-expandable particles is dispersed in the transparent ink in order to increase the dispersibility of the heat-expandable particles in the transparent ink and prevent aggregation. It is preferable to contain an agent.

  Examples of the white ink for covering the three-dimensional surface include the curable transparent ink containing a white pigment such as titanium oxide. The white ink preferably wets and spreads well when printed on a three-dimensional surface and has a lower viscosity than that of a transparent ink in consideration of covering the three-dimensional surface as uniformly as possible. The viscosity in is preferably 0.015 to 0.025 Pa · s. In order to adjust the viscosity, for example, the composition of the resin precursor to be used may be adjusted, the content of the white pigment may be adjusted, or a reactive diluent capable of reacting with the resin precursor may be added. .

  The content of the white pigment is preferably 5 to 20% by mass with respect to the total amount of components in the ink which form a solid content after curing to form a coating film covering the three-dimensional surface. If the content is less than the above range, the effect of imparting concealing property to the coating or adjusting the ground color may not be obtained due to the inclusion of the white pigment. In this case, since a large amount of white pigment is likely to be clogged in the nozzle of the first inkjet head 11 or the viscosity of the ink exceeds the preferred range described above, the ink is used as the nozzle. Therefore, there is a possibility that the ink cannot be discharged stably and satisfactorily. The white ink preferably contains a predetermined amount of a dispersant in order to enhance the dispersibility of the white pigment in the white ink and prevent aggregation.

《Colored ink》
As the colored ink to be discharged from the second inkjet head 12, water-based ink used for ordinary inkjet printing can be used. In consideration of coloring the three-dimensional shape, it is preferable that the surface of the three-dimensional shape or the surface of the white ink coating covering the surface is excellent in wettability and fixability, such wettability, As the ink having excellent fixability, it is preferable to use an ink colored by adding a pigment or the like to the curable ink similar to that described above.

  That is, the curable ink containing a pigment or dye of each color such as cyan, magenta, yellow, and black as a colorant in a predetermined ratio is preferably used as the color ink. When a pigment is used as the colorant, it is preferable to contain a predetermined amount of a dispersant in order to increase the dispersibility of the pigment in the ink and prevent aggregation. Considering that the colored ink is preferably ejected from the second inkjet head 12 as fine droplets of 3 to 20 pl as described above to reproduce fine depiction, The viscosity is preferably 0.008 to 0.012 Pa · s.

  When the curable ink is used as the colored ink, in the three-dimensional printing method using the inkjet printing apparatus 1 described above, the curable ink is ejected from the first inkjet head 11, After forming a three-dimensional shape on the surface of the printing material, and then performing printing and coloring by discharging colored curable ink from the second inkjet head 12, the carrier is operated while the curing means 13 is operated. The ink that forms the printing or coloring may be cured by reciprocating.

  For example, when the three-dimensional printing is performed on the surface of a resin film such as a polypropylene film as the printing material, each of the transparent ink, the white ink, and the colored ink is used, for example, wettability to the surface or fixing after curing. In order to improve the property, the surface tension at 25 ° C. is preferably 25 to 32 mN / m. In order to adjust the surface tension of the ink, for example, the composition of the resin precursor to be used may be adjusted, or a surfactant may be added.

  According to the three-dimensional printing method of the present invention, paper or resin is formed by forming braille on the surface of a planar printed material using a curable ink and forming a print using a colored ink. As described above, as a characteristic of the ink jet printing method, the conventional printing method is a print product in which the braille and the print are three-dimensionally printed on the surface of a general-purpose substrate such as a film without causing a deviation. Compared to the above, it becomes possible to manufacture very easily.

  In addition, according to the three-dimensional printing method of the present invention, a three-dimensional shape is formed on the surface of a planar printing body using a curable transparent ink, and then the surface of the three-dimensional shape is formed using a white ink. After the coating, the three-dimensional shape formed was colored on the surface of the general-purpose substrate by coloring the formed three-dimensional shape using a colored ink. For example, a three-dimensional painting in an oil painting style can be manufactured very easily as a characteristic of the ink jet printing method as compared with the conventional printing method.

《Curable ink》
As the curable ink for forming a three-dimensional shape on the surface of the printing material, the following transparent inks (i) and (ii) and a white ink, both of which are ultraviolet curable, were prepared.
<Transparent ink (i)>
Thermally expandable particles [Matsumoto Microsphere (registered trademark) F-30 manufactured by Matsumoto Yushi Seiyaku Co., Ltd., particle size: 10-20 μm, true specific gravity: 1.13, pore expansion ratio: about 70 times, shell Softening temperature: 80 to 85 ° C.] 20.0 parts by mass, dispersant [Solsperse (registered trademark) 36000 manufactured by The Lubrizol Corporation] 0.8 parts by mass, acrylate monomer [SR-238 manufactured by Sartomer] 79. 2 parts by mass was mixed for 1 hour using a paint shaker to prepare a dispersion.

Next, to 25.0 parts by mass of the dispersion, 19.8 parts by mass of an acrylate monomer [SR-238 manufactured by Sartomer], 25.0 parts by mass of an acrylate monomer [SR-351 manufactured by Sartomer], N 20.0 parts by mass of vinyl-2-pyrrolidone [manufactured by Nippon Shokubai Co., Ltd.] was added and stirred.
Next, 89.8 parts by mass of the above mixture was mixed with 5.0 parts by mass of an ultraviolet polymerization initiator [Irgacure (registered trademark) 1700 manufactured by Ciba Specialty Chemicals Co., Ltd.] and an ultraviolet polymerization initiator [Darocur (Ciba Specialty Chemicals Co., Ltd.) (Registered Trademark) 1173] 5.0 parts by mass and 0.2 parts by mass of a surfactant (TEGORAD 2100 manufactured by Degussa) were further stirred and then filtered using a membrane filter to obtain a thermal foaming property. A transparent ink (i) containing particles was produced. The transparent ink had a viscosity at 25 ° C. of 0.0252 Pa · s and a surface tension of 27.7 mN / m.

<Transparent ink (ii)>
39.8 parts by mass of an acrylate monomer [SR-238 manufactured by Sartomer], 30.0 parts by mass of an acrylate monomer [SR-351 manufactured by Sartomer], and N-vinyl-2-pyrrolidone [manufactured by Nippon Shokubai Co., Ltd.] ] 20.0 parts by mass were added and stirred.
Next, 89.8 parts by mass of the above mixture was mixed with 5.0 parts by mass of an ultraviolet polymerization initiator [Irgacure (registered trademark) 1700 manufactured by Ciba Specialty Chemicals Co., Ltd.] and an ultraviolet polymerization initiator [Darocur (Ciba Specialty Chemicals Co., Ltd.) (Registered Trademark) 1173] 5.0 parts by mass and 0.2 parts by mass of a surfactant (TEGORAD 2100 manufactured by Degussa) were further stirred and then filtered using a membrane filter to obtain a thermal foaming property. A transparent ink (i) containing no particles was produced. The transparent ink had a viscosity at 25 ° C. of 0.0241 Pa · s and a surface tension of 27.5 mN / m.

<White ink>
40.0 parts by mass of titanium oxide as a white pigment, 2.0 parts by mass of a dispersant [Solsperse (registered trademark) 36000 manufactured by The Lubrizol Corporation], and 58.0 parts by mass of an acrylate monomer (SR-238 manufactured by Sartomer) Were mixed for 1 hour using a paint shaker to prepare a dispersion.

Next, to 25.0 parts by mass of the dispersion, 19.8 parts by mass of an acrylate monomer [SR-238 manufactured by Sartomer], 25.0 parts by mass of an acrylate monomer [SR-351 manufactured by Sartomer], N 20.0 parts by mass of vinyl-2-pyrrolidone [manufactured by Nippon Shokubai Co., Ltd.] was added and stirred.
Next, 89.8 parts by mass of the above mixture was mixed with 5.0 parts by mass of an ultraviolet polymerization initiator [Irgacure (registered trademark) 1700 manufactured by Ciba Specialty Chemicals Co., Ltd.] and an ultraviolet polymerization initiator [Darocur (Ciba Specialty Chemicals Co., Ltd.) (Registered trademark) 1173] 5.0 parts by mass and 0.2 parts by mass of a surfactant [TEGORAD 2100 manufactured by Degussa] were further stirred, and then filtered using a membrane filter to produce a white ink. did. The white ink had a viscosity at 25 ° C. of 0.0203 Pa · s and a surface tension of 27.4 mN / m. The composition and characteristics of each ink are summarized in Table 1.

《着色されたインク》
被印刷体の表面に印字したり着色したりするための着色されたインクとしては、いずれも紫外線硬化性を有する４色のインクを用意した。すなわち、着色剤としての、下記いずれか１種の顔料１２．０質量部と、分散剤〔ザ リューブリゾル コーポレーション製のソルスパース（登録商標）３６０００〕０．８質量部と、アクリレートモノマー〔サートマー社製のＳＲ−２３８〕８７．２質量部とを、ペイントシャーカーを用いて１時間、混合して分散液を調製した。

《Colored ink》
As colored inks for printing or coloring on the surface of the printing material, four colors of ink having ultraviolet curing properties were prepared. That is, as a colorant, 12.0 parts by mass of any one of the following pigments, 0.8 part by mass of a dispersant (Solsperse (registered trademark) 36000 manufactured by The Lubrizol Corporation), and an acrylate monomer (manufactured by Sartomer) SR-238] 87.2 parts by mass were mixed using a paint shaker for 1 hour to prepare a dispersion.

(Coloring agent)
Cyan pigment: C.I. I. Pigment Blue 15: 3
Magenta pigment: C.I. I. Pigment Red 122
Yellow pigment: C.I. I. Pigment Yellow 12
Black pigment: C.I. I. Pigment Black 7
Next, to 25.0 parts by mass of the dispersion, 34.8 parts by mass of acrylate monomer [SR-238 manufactured by Sartomer], 10.0 parts by mass of acrylate monomer [SR-351 manufactured by Sartomer], N 20.0 parts by mass of vinyl-2-pyrrolidone [manufactured by Nippon Shokubai Co., Ltd.] was added and stirred.

  Next, 89.8 parts by mass of the above mixture was mixed with 5.0 parts by mass of an ultraviolet polymerization initiator [Irgacure (registered trademark) 1700 manufactured by Ciba Specialty Chemicals Co., Ltd.] and an ultraviolet polymerization initiator [Darocur (Ciba Specialty Chemicals Co., Ltd.) (Registered trademark) 1173] 5.0 parts by mass and 0.2 parts by mass of a surfactant [TEGORAD 2200N manufactured by Degussa] were further stirred and then filtered using a membrane filter to obtain cyan, magenta , Yellow and black inks were produced. The viscosity at 25 ° C. and the surface tension of each ink were as shown in Table 2.

《インクジェット印刷装置》
インクジェット印刷装置１としては、図１に示す構造を有すると共に、ピエゾ方式のメカニズムを有する第１および第２のインクジェットヘッド１１、１２を備え、かつ、前記第１のインクジェットヘッドから吐出されるインク滴の、１滴あたりの体積Ｖ₁が５０ｐｌと、第２のインクジェットヘッドから吐出されるインク滴の、１滴あたりの体積Ｖ₂が５ｐｌであるものを用意した。前記第１および第２のインクジェットヘッド１１、１２は、それぞれ、インク滴を吐出するためのノズルと、個々のノズルからインク滴を吐出させるためのメカニズムとを複数個ずつ備えた、いわゆるマルチノズルタイプとすると共に、第１のインクジェットヘッド１１は、透明インクと白色インクとを、個別に、インク滴として吐出できるものとし、第２のインクジェットヘッドは、前記４色のインクを、個別に、インク滴として吐出できるものとした。硬化手段１３としては、メタルハライドランプを用いた。インクカートリッジ１４としては、透明インクを充填する小室と、白色インクを充填する小室とを有すると共に、各小室から、対応するノズルに、個別に、透明インクまたは白色インクを供給できるものを用いた。さらに、インクカートリッジ１５としては、前記４色のインクを充填する４つの小室を有すると共に、各小室から、対応するノズルに、個別に、各色のインクを供給できるものを用いた。

<Inkjet printer>
The ink jet printing apparatus 1 includes first and second ink jet heads 11 and 12 having the structure shown in FIG. 1 and a piezo mechanism, and ink droplets ejected from the first ink jet head. A volume V ₁ per droplet of 50 pl and an ink droplet ejected from the second inkjet head having a volume V ₂ per droplet of 5 pl were prepared. Each of the first and second inkjet heads 11 and 12 is a so-called multi-nozzle type including a plurality of nozzles for ejecting ink droplets and a mechanism for ejecting ink droplets from each nozzle. In addition, the first inkjet head 11 is capable of ejecting transparent ink and white ink individually as ink droplets, and the second inkjet head individually ejects the four color inks into ink droplets. It can be discharged as. A metal halide lamp was used as the curing means 13. As the ink cartridge 14, a cartridge having a small chamber filled with transparent ink and a small chamber filled with white ink and capable of individually supplying transparent ink or white ink from each small chamber to the corresponding nozzle was used. Further, as the ink cartridge 15, an ink cartridge having four chambers filled with the four color inks and capable of individually supplying ink of each color from each chamber to the corresponding nozzle is used.

Example 1
One of the chambers of the ink cartridge 14 connected to the first ink jet head 11 of the ink jet printing apparatus 1 is filled with the transparent ink (i) containing the heat-expandable particles described above, and the second ink jet Each of the ink cartridges 14 and 15 was connected to the first and second inkjet heads 11 and 12 in a state where one small chamber of the ink cartridge 15 connected to the head 12 was filled with black ink. The tray 3 of the ink jet printing apparatus 1 accommodated a polypropylene film as a printing medium. Further, a computer for inputting electronically produced image data was connected to the inkjet printing apparatus 1.

  Then, by inputting electronically produced image data from the computer, the ink jet printing apparatus 1 is operated, and transparent ink is ejected from the first ink jet head 11 as ink droplets. From the second inkjet head 12 to reach the surface and preliminarily cure by irradiating ultraviolet rays by the curing means 13 to form a circular, braille precursor having a diameter of 1.6 mm on the surface; After the black ink is ejected as ink droplets to reach the surface of the polypropylene film and cured by irradiating with ultraviolet rays by the curing means 13 to print 8.0 points on the surface The tray 4 was discharged.

  Thereafter, the polypropylene film is allowed to stand for 60 minutes in a thermostatic bath at 150 ° C. to foam the thermally foamable particles, and the curing of the transparent ink and the black ink is completed. A three-dimensional printed material was obtained. As a result of confirming the printing, it was confirmed that the image was clear and did not deviate from Braille. Furthermore, when the braille was rubbed with a cotton swab while applying a load of 0.98 N, it was confirmed that the braille had sufficient practical durability without easily falling off the surface of the polypropylene film. It was.

Example 2
One of the small chambers of the ink cartridge 14 connected to the first inkjet head 11 of the inkjet printing apparatus 1 is filled with the transparent ink (ii) that does not contain the heat-expandable particles described above, and the other small chamber. The ink cartridge 14 was connected to the first inkjet head 11 in a state in which the white ink was filled. Further, the ink cartridge 15 connected to the second inkjet head 12 is filled with ink of each color of cyan, magenta, yellow, and black, and the ink cartridge 15 is connected to the second ink jet head 12. The ink jet head 12 was connected. The tray 3 of the ink jet printing apparatus 1 accommodated a polypropylene film as a printing medium. Further, a computer for inputting electronically produced image data was connected to the inkjet printing apparatus 1.

  Then, by inputting electronically produced image data from the computer, the ink jet printing apparatus 1 is operated, and transparent ink is ejected from the first ink jet head 11 as ink droplets. A step of forming a three-dimensional shape on the surface by irradiating and curing the ultraviolet ray by the curing means 13 and discharging the white ink as ink droplets from the first inkjet head 11, The surface of the shape is reached and cured by irradiating the ultraviolet ray with the curing means 13 to cover the solid shape, and the four inks are ejected from the second inkjet head 12 to form the solid shape. The surface is made to reach the surface and is cured by irradiating with ultraviolet rays by the curing means 13, After repeating the step of coloring the Jo, it was discharged to the tray 4.

  Thereafter, the polypropylene film was allowed to stand for 60 minutes in a thermostatic bath at 150 ° C. to complete the curing of each ink to obtain an oil painting-style three-dimensional painting. As a result of observing the surface of the three-dimensional painting, it was confirmed that the swell of the oil paint expressed by the three-dimensional shape was colored without any deviation and reproduced like a real oil painting.

It is a schematic sectional drawing of the paper feed direction which shows the internal structure of an example of embodiment of the inkjet printing apparatus of this invention used in order to implement the three-dimensional printing method of this invention. It is a schematic sectional drawing of the direction orthogonal to a paper feeding direction which shows the internal structure of the inkjet printing apparatus of the said example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet printing apparatus 2 Housing | casing 3 Tray 4 Tray 5 Roller 6 Roller 7 Roller 8 Roller 9 Guide member 10 Conveyance path 11 First inkjet head 12 Second inkjet head 13 Curing means 14 Ink cartridge 15 Ink cartridge

Claims (7)

A first inkjet head for ejecting curable ink as ink droplets to reach the surface of a planar printing medium and a colored ink as ink droplets for reaching the surface A second inkjet head, and a curing means for curing or pre-curing the curable ink that has reached the surface, and 1 of the ink droplets ejected from the first inkjet head The volume V ₁ [pl] per droplet and the volume V ₂ [pl] per droplet of the ink droplets ejected from the second inkjet head are expressed by the formula (1):
V ₁ ≧ V ₂ × 10 (1)
And curable ink is ejected as ink droplets from the first ink jet head using an ink jet printing apparatus having V _{2 of 3} to 20 pl, and reaches the surface of the planar printing medium. A step of forming a three-dimensional shape or a precursor thereof on the surface by curing or pre-curing by a curing means, and discharging the colored ink as ink droplets from the second inkjet head, A three-dimensional printing method comprising performing three-dimensional printing on the surface through at least one of printing on the surface and coloring.   The curable ink is ejected as ink droplets from the first inkjet head to reach the surface of the planar printing medium and is cured by a curing means to form a three-dimensional shape on the surface, The three-dimensional printing method according to claim 1, wherein at least one of printing on the surface and coloring is performed by discharging colored ink as ink droplets from the second inkjet head.   As the curable ink, an ink containing thermally foamable particles that are foamed by heating is used, and the ink is ejected as ink droplets from the first inkjet head to reach the surface of the planar printing medium and cured. Precuring by means to form a three-dimensional precursor on the surface, and then discharging colored ink from the second inkjet head as ink droplets, printing on the surface, and coloring The three-dimensional printing method according to claim 1, wherein after performing at least one of the steps, the printing medium is heated to foam the thermally foamable particles and the ink is cured to form a three-dimensional shape.   A photo-curable ink is used as the curable ink containing thermally foamable particles, and the ink that has reached the surface of the planar printing medium by light irradiation from the light irradiation unit as the curing unit is preliminarily used. The three-dimensional printing method of Claim 3 made to harden | cure.   The three-dimensional printing method according to any one of claims 1 to 4, wherein a braille is formed on a surface of a planar printing material using a curable ink and a print is formed using a colored ink.   A three-dimensional shape is formed on the surface of the planar printing medium using a curable transparent ink, and then the surface of the three-dimensional shape is coated with a white ink, and then a colored ink is used. The three-dimensional printing method according to claim 1, wherein the formed three-dimensional shape is colored to form a three-dimensional painting. An inkjet printing apparatus for carrying out the three-dimensional printing method according to any one of claims 1 to 6, wherein curable ink is ejected as ink droplets to reach the surface of a planar printing medium. The first inkjet head, the second inkjet head for discharging the colored ink as ink droplets to reach the surface, and the curable ink reaching the surface is cured or precured. And a volume V ₁ [pl] of ink droplets ejected from the first inkjet head, and ink droplets ejected from the second inkjet head, The volume V ₂ [pl] per drop is expressed by the formula (1):
V ₁ ≧ V ₂ × 10 (1)
And an ink jet printing apparatus characterized in that V ₂ is 3 to ₂₀ pl.

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