JP6379912B2 - Surface flattening method and surface flattening apparatus - Google Patents

Description

  The present invention relates to a surface flattening method and a surface flattening apparatus that perform printing on an inflatable sheet in which a predetermined region expands and becomes three-dimensional by injection of energy such as heat and light.

  As one type of three-dimensional forming technology for forming a three-dimensional printed matter, black ink or toner is printed in a desired pattern on a thermally expandable sheet that is foamed by heating to increase its volume, and then the thermally expandable sheet. A technique for uniformly irradiating light on the entire surface of the substrate is known. This technology utilizes the fact that a thermally expandable sheet has a higher heat absorption rate and is heated to a higher temperature than a non-printed area in which black ink or toner is printed. The region of the thermally expandable sheet on which the toner is printed is expanded by foaming. Patent Literature 1 describes a three-dimensional printing apparatus using this technique.

JP 2012-171317 A

  By the way, on the surface of the thermally expandable sheet three-dimensionalized by the above technique, unintended minute irregularities generated by condensation of the thermally expandable microcapsules in the thermally expandable sheet are formed. For this reason, when an image is printed using the three-dimensional heat-expandable sheet as a printing medium, irregularities are also formed on the surface of the printed matter (printed result). In particular, when a facial photograph or the like is printed on a thermally expandable sheet, the influence of the presence of the unevenness on the quality (image quality) of the printed material cannot be ignored.

  Such a problem is not limited to the thermally expandable sheet. The heat-expandable sheet has a heat-expandable microcapsule (also referred to as a heat-expandable microcapsule) that expands by heat. For example, a sheet having a light-expandable microcapsule that expands by light (hereinafter referred to as light expansion) The same problem may occur even in any inflatable sheet such as an expandable sheet.

  In view of the above circumstances, an object of the present invention is to provide a technique for obtaining a high-quality printed matter from an inflatable sheet that is expanded and three-dimensionalized by energy injection.

According to one embodiment of the present invention, a first ink layer is formed by ejecting ink onto the surface side of an inflatable sheet whose surface is expanded and three-dimensionalized, and a first time from the formation of the first ink layer. After the lapse of time, the first ink layer is cured , and ink is ejected onto the first ink layer on the surface side of the inflatable sheet on which the first ink layer is formed to form a second ink layer. Provided is a surface planarization method for forming and curing the second ink layer after a second time different from the first time since the formation of the second ink layer.

  In the surface flattening method, the second ink layer may be made of a color ink that colors the expandable sheet, and the first time may be longer than the second time. Furthermore, before the formation of the first ink layer, a third ink layer may be formed by directly ejecting ink onto the surface of the expandable sheet, and the third ink layer may be cured. Furthermore, at least one of the first ink layer and the third ink layer may be composed of a single color ink that assists the color development of the second ink layer.

  In the surface flattening method, the second ink layer may be made of a color ink that colors the expandable sheet, and the first time may be longer than the second time. Furthermore, the ink layer formed immediately below the second ink layer may be composed of a single color ink that assists the color development of the second ink layer.

  In the surface flattening method, the first ink layer is formed by directly ejecting the ink onto the surface of the expandable sheet, and the second time is less than the first time. May be longer.

According to another aspect of the present invention, the first ink layer is formed by ejecting the first ink onto the surface side of the inflatable sheet whose surface is expanded to form a three-dimensional structure, and the first ink layer is formed. The first ink layer is cured after elapse of a predetermined time, and the first ink is placed on the first ink layer on the surface side of the expandable sheet on which the first ink layer is formed. Is a surface that forms a second ink layer by ejecting a second ink having different viscosities, and hardens the second ink layer after the predetermined time has elapsed since the formation of the second ink layer. A planarization method may be provided.

Still another embodiment of the present invention includes a layer forming unit that forms an ink layer by ejecting ink onto an inflatable sheet whose surface is expanded and three-dimensionalized, and the ink layer is irradiated with light to cure the ink layer. A layer curing unit for causing the layer to form, a first ink layer that is the ink layer formed on the surface side of the expandable sheet by the layer forming unit, and the layer forming unit on the surface side of the expandable sheet. Control means for controlling the layer curing means so that the time from the formation of the ink layer to curing differs between the second ink layer, which is the ink layer formed on the first ink layer , and A surface flattening apparatus may be provided.

Still another embodiment of the present invention includes a layer forming unit that forms an ink layer by ejecting ink onto an inflatable sheet whose surface is expanded and three-dimensionalized, and the ink layer is irradiated with light to cure the ink layer. A layer curing unit for causing the layer to form, a first ink layer that is the ink layer formed on the surface side of the expandable sheet by the layer forming unit, and the layer forming unit on the surface side of the expandable sheet. Control means for controlling the layer curing means so that the time from formation of the ink layer to curing is the same for the second ink layer, which is the ink layer formed on the first ink layer; And a surface flattening device in which the viscosity of the first ink layer is different from the viscosity of the second ink layer.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which obtains a high quality printed matter from the expandable sheet which expanded | swelled and solidified by energy injection | pouring can be provided.

1 is a diagram illustrating a configuration of a stereoscopic image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating the configuration of an inkjet printer unit of a stereoscopic image forming apparatus according to an embodiment of the present invention, and is a diagram of the configuration of the inkjet printer unit viewed from the side. FIG. 2 is a diagram illustrating the configuration of an inkjet printer unit of a stereoscopic image forming apparatus according to an embodiment of the present invention, and is a diagram of the configuration of the inkjet printer unit viewed from above. 1 is a circuit block diagram including a control device of a stereoscopic image forming apparatus according to an embodiment of the present invention. It is a figure for demonstrating the surface shape of the three-dimensional recording medium. It is a figure for demonstrating the conventional printing method. It is a figure for demonstrating the printing method which concerns on one Embodiment of this invention. 3 is a flowchart of a printing method according to an embodiment of the present invention. FIG. 10 is a diagram comparing an image printed by a conventional printing method and an image printed by a printing method according to an embodiment of the present invention. It is the figure shown about the laminated structure of the ink layer from Example 1 of this invention to Example 5, and its effect. It is a flowchart of the printing method which concerns on the modification of this invention.

  FIG. 1 is a diagram illustrating the configuration of a stereoscopic image forming apparatus 1 (surface planarization apparatus) according to an embodiment of the present invention. As shown in FIG. 1, a stereoscopic image forming apparatus 1 includes a black toner printing unit 2 provided at the bottom, a thermal expansion processing unit 3 provided on the black toner printing unit 2, and an inkjet printer unit 4 provided at the top. And.

  The black toner printing unit 2 includes an endless transfer belt 6 that extends in the horizontal direction at the center inside the apparatus housing 5. The transfer belt 6 is stretched by a tension mechanism (not shown) and is stretched between a driving roller 7 and a driven roller 8. The transfer belt 6 is driven by a driving roller 7 to circulate in a counterclockwise direction indicated by an arrow a in the figure.

  A photosensitive drum 11 of the image forming unit 9 is disposed in contact with the circulation moving surface on the transfer belt 6. A developing roller 12 and the like are arranged on the photosensitive drum 11 so as to surround the peripheral surface thereof, following a cleaner, an initialization charger, and an optical writing head (not shown).

  The developing roller 12 is disposed in the side opening of the toner container 13. A black toner K is stored in the toner container 13. The black toner K is made of a non-magnetic one-component toner. The developing roller 12 carries a thin layer of black toner K contained in the toner container 13 on the surface, and blackens the electrostatic latent image formed on the peripheral surface of the photosensitive drum 11 by the optical writing head. Develop with toner K.

  A primary transfer roller 14 is pressed against the lower portion of the photosensitive drum 11 via the transfer belt 6, thereby forming a primary transfer portion. A bias voltage is supplied to the primary transfer roller 14 from a bias power source (not shown). The primary transfer roller 14 applies a bias voltage supplied from a bias power source to the transfer belt 6, and transfers an image developed with black toner K on the peripheral surface of the photosensitive drum 11 to the transfer belt 6.

  A secondary transfer roller 15 is pressed against the driven roller 8 across the right end portion of the transfer belt 6 shown in FIG. 1 via the transfer belt 6, thereby forming a secondary transfer portion. A bias voltage is supplied to the secondary transfer roller 15 from a bias power source (not shown). The secondary transfer roller 15 applies a bias voltage supplied from a bias power source to the transfer belt 6, and an image of the black toner K primarily transferred to the transfer belt 6 is indicated by an arrow along the image forming conveyance path 16. Thus, the image is transferred to the recording medium 17 conveyed from below in FIG.

  Note that a thermally expandable sheet is used for the recording medium 17 (also referred to as a printing medium) of this example. A thermally expansible sheet consists of a base material and the foaming layer coated on this base material. The base material is made of a cloth such as paper or canvas, a panel material such as plastic, and the material is not particularly limited. The foamed layer is a layer having a property of foaming by heating to increase its volume, and is made of a resin containing thermally expandable microcapsules.

  The recording medium 17 is stacked and stored in a recording medium storage unit 18 including a paper feed cassette, and the uppermost sheet is taken out by a paper supply roller (not shown) and sent out to the image forming conveyance path 16. Thereafter, the image is conveyed through the image forming conveyance path 16, and the image of the black toner K is transferred when passing through the secondary transfer portion.

  The recording medium 17 to which the image of the black toner K is transferred is conveyed along the fixing conveyance path 19 to the fixing unit 21. The heating roller 22 and the pressing roller 23 of the fixing unit 21 sandwich the recording medium 17 and convey it while applying heat and pressure. As a result, the image of the black toner K that has been secondarily transferred is fixed on the recording medium 17. Thereafter, the recording medium 17 is further conveyed by the heating roller 22 and the pressing roller 23 and is discharged to the thermal expansion processing unit 3 above the black toner printing unit 2 by the fixing unit discharge roller pair 24. Note that the conveyance speed of the recording medium 17 (thermally expandable sheet) in the fixing unit 21 is relatively fast. For this reason, the portion of the thermally expandable sheet on which the image of the black toner K is printed (hereinafter, the black toner print portion) does not expand due to the heating by the heating roller 22.

  In the thermal expansion processing unit 3, a medium transport path 25 is formed at the top, and four transport roller pairs 26 (26 a, 26 b, 26 c, 26 d) are arranged along the medium transport path 25. A heat ray radiating unit 27 is disposed substantially below the center of the medium transport path 25. The heat ray radiating section 27 includes a halogen lamp 27a and a reflecting mirror 27b having a substantially semicircular cross section surrounding the lower half of the halogen lamp 27a. In this example, a 900 W lamp is used as the halogen lamp 27a, and is arranged at a position 4 cm away from the surface of the recording medium 17 conveyed through the medium conveyance path 25. The conveyance speed of the conveyance roller pair 26 that conveys the recording medium 17 is 20 mm / second. Under this condition, the recording medium 17 is heated to 100 ° C. to 110 ° C., and the black toner print portion of the recording medium 17 is thermally expanded.

Although the recording speed of the recording medium 17 in the black toner printing unit 2 is high and the conveying speed of the recording medium 17 in the thermal expansion processing unit 3 is low, the recording medium 17 is conveyed from the recording medium storage unit 18 one by one. Continuous conveyance is not performed until conveyance in the thermal expansion processing part 3 is completed. Therefore, the recording medium 17 conveyed to the thermal expansion processing unit 3 is bent along the conveyance path b between the fixing unit discharge roller pair 24 of the black toner printing unit 2 and the first conveyance roller pair 26a of the thermal expansion processing unit 3. In the state where it stays, there is no inconvenience in conveyance as a whole only by staying for a short time. The conveyance roller pair 26 may be constituted by a pair of long rollers extending in the width direction of the recording medium 17 orthogonal to the conveyance direction, or a short length that conveys the recording medium 17 while sandwiching only both end portions thereof. It can also be composed of a pair of rollers.
The recording medium 17 in which the black toner printing portion is thermally expanded by the thermal expansion processing unit 3 and is three-dimensionalized is carried into the inkjet printer unit 4 along the conveyance path c.

  2 and 3 are diagrams illustrating the configuration of the inkjet printer unit 4 of the stereoscopic image forming apparatus 1 according to the embodiment of the invention. FIG. 2 is a side view of the configuration of the inkjet printer unit 4, and FIG. 3 is a diagram of the configuration of the inkjet printer unit 4 viewed from above.

  The ink jet printer unit 4 is, for example, an ink jet printing apparatus that uses ink containing ultraviolet curable resin (hereinafter referred to as UV ink). As shown in FIG. 2, the inkjet printer unit 4 includes a transport unit 30 that transports a three-dimensional recording medium 17 in which a predetermined area is expanded, and a head unit (printer head 34 a, And a light source unit (light source 35a, light source 35b) for irradiating ultraviolet rays.

  The conveyance unit 30 includes a drive roller 31, a driven roller 32, and a conveyance belt 33 that is stretched over the drive roller 31 and the driven roller 32. The transport unit 30 transports the recording medium 17 that is a thermally expandable sheet in the transport direction by the transport belt 33 being driven by the rotation of the drive roller 31 and circulated in the clockwise direction indicated by the arrow in FIG. .

  The head unit includes a printer head 34a and a printer head 34b that discharge UV ink at different positions in the transport direction. The printer head 34a is configured to eject color (cyan C, magenta M, yellow Y) UV ink, and the printer head 34b is configured to eject white W UV ink. The printer head 34a and the printer head 34b are layer forming units that form ink layers by ejecting UV ink onto the three-dimensional recording medium 17.

  Although FIG. 2 shows an example in which two printer heads are provided, three or more printer heads may be provided. Further, the UV ink ejected from the printer head is not limited to the color and white W UV ink, and other UV ink such as clear UV ink may be ejected.

  The light source unit includes a light source 35a and a light source 35b that irradiate ultraviolet rays to cure UV ink at different positions in the transport direction. The light source 35a is configured to irradiate the color UV ink discharged from the printer head 34a with ultraviolet rays, and the light source 35b is configured to irradiate the white W UV ink discharged from the printer head 34b with ultraviolet rays. The light source 35a and the light source 35b are layer curing means for irradiating the ink layer formed on the recording medium 17 with the printer head 34a and the printer head 34b with ultraviolet rays to cure the ink layer.

  As shown in FIG. 3, one light source 35a is provided on each side in the scanning direction of the printer head 34a orthogonal to the transport direction with respect to the printer head 34a, and moves in conjunction with the printer head 34a. It is configured. One light source 35b is also provided on each side of the printer head 34b in the scanning direction with respect to the printer head 34b, and is configured to move in conjunction with the printer head 34b.

  FIG. 4 is a circuit block diagram including a control device of the stereoscopic image forming apparatus 1 shown in FIG. As shown in FIG. 4, an I / F_CONT (interface controller) 46, a PR_CONT (printer controller) 47, and an image cutout unit 48 are connected to a CPU (central processing unit) 45 via a data bus, respectively. Has been.

  A printer printing unit 49 is connected to PR_CONT 47. The image cutout unit 48 is also connected to the I / F_CONT 46. The image cutout unit 48 is loaded with an image processing application.

The CPU 45 is connected to a ROM (read only memory) 51, an EEPROM (electrically erasable programmable ROM) 52, an operation panel 53, and a sensor unit 54 to which an output from a sensor arranged in each unit is input. The ROM 51 stores a system program. The operation panel 53 includes a touch-type display screen.
The CPU 45 reads a system program stored in the ROM 51 and controls each unit according to the read system program.

  The I / F_CONT 46 converts, for example, print data supplied from a host device such as a personal computer into bitmap data and develops it in the frame memory 55.

  In the frame memory 55, storage areas corresponding to the print data of black toner K and the print data of white W, cyan C, magenta M, and yellow Y color ink are set. In this storage area, the print data of each color image is converted into bitmap data and developed. The developed data (denoted as image data) is output to PR_CONT 47, and is output from PR_CONT 47 to the printer printing unit 49.

  The printer printing unit 49 is an engine unit, and controls operations of the black toner printing unit 2, the thermal expansion processing unit 3, and the inkjet printer unit 4 shown in FIG. 1 under the control of the PR_CONT 47. That is, in the stereoscopic image forming apparatus 1, the printer printing unit 49 is a control unit that controls the operation of each unit.

  Then, the image data of the black toner K output from the PR_CONT 47 is supplied from the printer printing unit 49 to the optical writing head (not shown) of the image forming unit 9 of the black toner printing unit 2 shown in FIG.

  Also, the image data of the white W, cyan C, magenta M, and yellow Y color inks output from the PR_CONT 47 is supplied to the printer head 34a and the printer head 34b shown in FIGS.

  FIG. 5 is a diagram for explaining the surface shape of the three-dimensional recording medium 17. FIG. 6 is a diagram for explaining a conventional printing method. FIG. 7 is a diagram for explaining a printing method according to an embodiment of the present invention. FIG. 8 is a flowchart of a printing method according to an embodiment of the present invention. FIG. 9 is a diagram comparing an image printed by a conventional printing method and an image printed by a printing method according to an embodiment of the present invention.

The three-dimensional recording medium 17 will be described with reference to FIG.
Even if the recording medium 17 conveyed to the ink jet printer unit 4 is printed and processed so as to be three-dimensionalized at a certain height by the black toner printing unit 2 and the thermal expansion processing unit 3, strictly speaking, It is not three-dimensionalized to a certain height. As shown in FIG. 5, minute irregularities are formed with a period of about 0.3 mm to 1.0 mm, for example. One reason for this is that the thermally expandable microcapsules 17b are foamed and aggregated in the resin 17a whose fluidity has been increased by heating the recording medium 17, and the aggregated part rises more than the other part. Is considered.

A conventional printing method for printing an image on a three-dimensional recording medium 17 will be described with reference to FIG.
When a color image is printed by the conventional printing method, first, the printer head 34 b ejects white W UV ink onto the recording medium 17 under the control of the printer printing unit 49. As a result, a white W ink layer 60 is formed as a base of a color image. Thereafter, under the control of the printer printing unit 49, the light source 35b irradiates the ink layer 60 with ultraviolet rays to cure the ink layer 60. Further, the printer head 34 a ejects color UV ink onto the ink layer 60 to form a color ink layer 61 (that is, a color image). Finally, in order to prevent the color image from bleeding, the light source 35a immediately irradiates the ink layer 61 with ultraviolet rays to cure the ink layer 61.

  In the conventional printing method, in order to shorten the printing time, the printer printing unit 49 controls the light source 35b so that the ink layer 60 is irradiated with ultraviolet rays immediately after the layer formation, similarly to the ink layer 61. It is normal. As a result, as shown in FIG. 6, the amplitude of the unevenness of the three-dimensional recording medium 17 (the height of the foam layer in the direction orthogonal to the surface of the base material of the recording medium 17 on which the foam layer is formed). The difference between the high portion and the low portion is inherited by the ink layer 60 and the ink layer 61.

A printing method (surface flattening method) according to an embodiment of the present invention for printing an image on the three-dimensional recording medium 17 will be described.
The printing method according to an embodiment of the present invention is different from the conventional printing method in that the unevenness of the three-dimensional recording medium 17 is absorbed by the ink layer (the amplitude of the unevenness is reduced by the ink layer). Is different. Absorption of irregularities is realized by ejecting ink onto the recording medium 17 to form an ink layer and then curing the ink layer after a lapse of time until the upper surface of the ink layer becomes approximately flat. . The time until the upper surface becomes approximately flat varies depending on various conditions such as the viscosity of the ink and the degree of unevenness, but at least after the ink layer is formed, the ink layer is cured after a longer time than before, The effect of suppressing unevenness is obtained compared to the conventional case. In order to shorten the time until flattening, it is desirable that the ink has a low viscosity.

The above-described printing method according to an embodiment of the present invention will be described more specifically with reference to FIGS.
When printing a color image by the printing method according to an embodiment of the present invention, first, the printer head 34 b directly discharges white W UV ink onto the surface of the recording medium 17 under the control of the printer printing unit 49. Thus, the white W ink layer 60 serving as the base of the color image is formed so that the ink layer 60 contacts the surface of the recording medium 17 (step S1). Thereafter, under the control of the printer printing unit 49, after the second time has elapsed from the formation of the ink layer 60, the light source 35b irradiates the ink layer 60 with ultraviolet rays to cure the ink layer 60 (step S2). Note that the processing in step S1 and step S2 is the same as the conventional printing method.

  Next, under the control of the printer printing unit 49, the printer head 34b discharges the white W UV ink onto the ink layer 60 to form the white W ink layer 62 that functions as an absorption layer that absorbs irregularities ( Step S3). The light source 35b does not immediately irradiate the ink layer 62 with ultraviolet rays. The light source 35b cures the ink layer 62 by irradiating the ink layer 62 with ultraviolet light after a first time different from the second time has elapsed since the formation of the ink layer 62 (step S4). Here, the first time is longer than the second time, and is, for example, 5 to 10 minutes. On the other hand, the second time is, for example, about several seconds. By performing such light emission control in the printer printing unit 49, the upper surface of the ink layer 62 becomes flatter than the upper surface of the ink layer 60, and the unevenness of the recording medium 17 is absorbed. The first time may be longer than the second time, and 5 to 10 minutes is merely an example. Depending on various conditions such as the viscosity of the ink used to form the ink layer 62, for example, even if it is several tens of seconds to 2 or 3 minutes, the first time is set to be the same as the second time. In comparison, the ink layer can absorb the unevenness of the three-dimensional recording medium 17.

  Lastly, under the control of the printer printing unit 49, the color UV ink for coloring the recording medium 17 is ejected onto the ink layer 62 having a flat upper surface by the printer head 34a to form the color ink layer 61 ( Step S5). Thereafter, after the second time has elapsed from the formation of the ink layer 61, the light source 35a irradiates the ink layer 61 with ultraviolet rays to cure the ink layer 61 (step S6).

  According to the above printing method, the unevenness of the recording medium 17 is absorbed by the ink layer 62 and the unevenness generated on the upper surface of the ink layer 62 is suppressed (the amplitude of the unevenness is reduced). For this reason, the unevenness | corrugation which arises on the upper surface of the color image (ink layer 61) formed on the ink layer 62 is also suppressed. Therefore, as shown in the right half of FIG. 9, a high-quality printed matter in which smooth skin texture is appropriately expressed can be obtained from the three-dimensional recording medium 17. In addition, the left half of FIG. 9 shows the printing result by the conventional printing method, and the right half shows the printing result by the printing method described above.

  7 and 8 show an example in which the ink layer 62 that is an absorption layer is formed on the ink layer 60 as a base, but the absorption layer may be formed directly on the recording medium 17. That is, step S1 and step S2 in FIG. 8 may be omitted. As a result, the number of ink layers can be reduced and the time required for printing can be shortened. However, from the viewpoint of obtaining a high quality image by eliminating the influence of the unevenness of the recording medium 17, the absorbing layer is not formed directly on the recording medium 17, but another ink as shown in FIGS. 7 and 8. Desirably, it is formed on layer 60. This is because, by forming the absorption layer on another ink layer, the upper surface of the absorption layer can be made flatter than when the absorption layer is formed directly on the surface of the recording medium 17. As for this action, for example, the ink layer formed between the absorption layer and the recording medium 17 functions as a so-called sealing layer, so that the ink constituting the absorption layer soaks into the recording medium 17. This may be due to the prevention of

  7 and 8 show an example in which the ink layer 61 constituting the color image is formed, but the formation of the ink layer 61 made of color ink may be omitted if coloring is not necessary. That is, step S5 and step S6 in FIG. 8 may be omitted.

  7 and 8 show an example in which both the ink layer 60 and the ink layer 62 are made of white W ink, but at least one of the ink layer 60 and the ink layer 62 assists the color development of the ink layer 61. It may be formed with white W ink. However, from the viewpoint of obtaining an image having a desired hue by eliminating the influence of the black toner K attached to the black toner printing unit 2 for three-dimensionalization, as shown in FIGS. 7 and 8, the ink layer 60 and the ink are used. It is desirable to form both layers 62 with white W ink. In order to make the color tone more appropriate, three or more white W ink layers may be formed.

  Furthermore, when one of the ink layer 60 and the ink layer 62 is printed with the white W ink and the other is printed with, for example, a transparent clear ink, the ink layer 61 is formed to be in contact with the ink layer 61 immediately below the ink layer 61. It is desirable to form the formed ink layer 62 with white W ink. This is because some printing apparatuses do not eject ink to the white W portion of the color image. In such a printing apparatus, the ink layer 61 is formed on the white W portion of the color image. This is because the ink layer 62 immediately below the layer is exposed on the surface. When the ink layer 62 is formed of clear ink, the clear ink is exposed in the white W portion of the color image, and the finish is stronger than in other portions. Thus, such a situation can be prevented by forming the ink layer 62 with the white W ink.

  7 and 8 show an example in which only one absorption layer is formed, two or more absorption layers may be formed. Thereby, the influence of the unevenness of the recording medium 17 can be more reliably eliminated.

  FIG. 10 is a diagram showing the laminated structure of ink layers formed on the recording medium 17 and the effects thereof. Hereinafter, with reference to FIG. 10, Examples 1 to 5 having different ink layer stacking configurations will be described.

  Example 1 shown in FIG. 10 is an example in which three ink layers are formed on the recording medium 17, and in order from the recording medium 17 side, a white W ink layer, a white W ink layer (absorption layer), and a color ink layer. It has a configuration in which ink layers are laminated. This configuration is the same as the configuration shown in FIG.

  Example 2 shown in FIG. 10 is an example in which three ink layers are formed on the recording medium 17, and in order from the recording medium 17 side, a white W ink layer, a clear ink layer (absorption layer), and a color ink. It has a configuration in which layers are stacked.

  Example 3 shown in FIG. 10 is an example in which four ink layers are formed on the recording medium 17, and in order from the recording medium 17 side, a white W ink layer, a clear ink layer (absorption layer), and a white W layer. The ink layer and the color ink layer are stacked.

  Example 4 shown in FIG. 10 is an example in which three ink layers are formed on the recording medium 17, and in order from the recording medium 17 side, a white W ink layer (absorbing layer), a white W ink layer, and a color ink layer. It has a configuration in which ink layers are laminated.

  Example 5 shown in FIG. 10 is an example in which three ink layers are formed on the recording medium 17, and in order from the recording medium 17 side, a clear ink layer (absorbing layer), a white W ink layer, and a color ink. It has a configuration in which layers are stacked.

  In any of the configurations of Example 1 to Example 5, since the absorption layer is provided below the color ink layer, unevenness appearing in the color image can be suppressed. In particular, in the configurations of Example 1 to Example 3, since the absorption layer is not directly formed on the recording medium 17 but is formed on another ink layer, a higher unevenness suppressing effect can be obtained. .

  In any of the configurations of the first to fifth embodiments, since the white W ink layer is formed below the color ink layer, a color image with good hue can be obtained. In particular, in the configurations of the first embodiment, the third embodiment, and the fourth embodiment, since the plurality of white W ink layers are formed, the hue of the color image can be further improved.

  In the configurations of Example 1 and Examples 3 to 5, a white W ink layer is formed immediately below the color ink layer. For this reason, even when printing is performed by a printing apparatus that does not print white W in color printing, the white W portion of the image can be prevented from having a different finish from the other portions. .

  Note that when the number of ink layers to be formed is smaller, the time required for printing can be shortened, and the amount of ink consumed for printing can be suppressed, so that the printing cost can be reduced. On the other hand, if the effects as shown in FIG. 10 are taken into consideration and the ink layers are appropriately combined, a higher quality image can be obtained when the number of ink layers to be formed is larger.

  In each of the above-described embodiments, the time from the formation of the ink layer 62 serving as the absorbing layer to the time when the ink layer 62 is cured by irradiating the ultraviolet rays is determined from the time when the ink layer 60 serving as a layer other than the absorbing layer is formed. Although the absorption layer that absorbs the irregularities is formed by making it longer than the time until the ink layer 60 is cured by irradiation, the method of forming the absorption layer is not limited to this. For example, the time from the formation of the ink layer 62 to be the absorption layer to the time when the ink layer 62 is cured by irradiating the ultraviolet ray, and the time from the formation of the ink layer 60 to be a layer other than the absorption layer to which the ink layer 60 is irradiated A material having the same time to be cured and having a viscosity lower than that of the material of the ink layer 60 other than the absorbing layer may be used as the material of the ink layer 62 serving as the absorbing layer. When the time from the formation of the ink layers 60 and 62 to the curing thereof is the same, the smaller the viscosity of the material of the ink layers 60 and 62, the more easily the material spreads. This is because the effect is high.

With reference to FIGS. 7 and 11, the printing method according to the above-described modification of the present invention will be described more specifically. Note that the description of the same processing as in the above embodiment will be omitted as appropriate.
The step (step S11) for forming the ink layer 60 as the base and the step (step S12) for curing the ink layer 60 are the same as the above-described step S1 and step S2, respectively.

  Next, as in the above-described embodiment, the white W ink layer 62 that functions as an absorption layer that absorbs irregularities is formed. The UV ink that forms the ink layer 62 is white that serves as the base of a color image. An ink having a viscosity lower than that of the UV ink forming the W ink layer 60 is used (step S13). Thereafter, under the control of the printer printing unit 49, after the second time has elapsed from the formation of the ink layer 62, the light source 35b irradiates the ink layer 62 with ultraviolet rays to cure the ink layer 62 (step S14).

  Finally, the step of forming the color ink layer 61 (step S15) and the step of curing the ink layer 61 by irradiating the ink layer 61 with ultraviolet rays (step S16) are the same as the above-described steps S5 and S6, respectively. is there.

  According to the above printing method, the unevenness of the recording medium 17 is absorbed by the ink layer 62 and the unevenness generated on the upper surface of the ink layer 62 is suppressed. For this reason, the unevenness | corrugation which arises on the upper surface of the color image (ink layer 61) formed on the ink layer 62 is also suppressed.

  The above-described embodiments and modifications are specific examples for facilitating the understanding of the invention, and the present invention is not limited to these embodiments. The surface flattening method and the surface flattening apparatus can be variously modified and changed without departing from the spirit of the present invention defined by the claims.

Hereinafter, the invention described in the scope of claims at the beginning of the application of the present application will be added.
[Appendix 1]
Forming a first ink layer by discharging ink to the surface side of the inflatable sheet that has been three-dimensionalized by expanding the surface;
Curing the first ink layer after a first time has elapsed since the formation of the first ink layer;
Forming a second ink layer by ejecting ink onto the surface side of the inflatable sheet on which the first ink layer is formed;
A method for planarizing a surface, comprising: curing the second ink layer after a lapse of a second time different from the first time since the formation of the second ink layer.

[Appendix 2]
In the surface planarization method according to attachment 1,
The second ink layer is made of a color ink that colors the expandable sheet,
The method for planarizing a surface, wherein the first time is longer than the second time.

[Appendix 3]
In the surface flattening method according to appendix 2, further, before forming the first ink layer,
Forming a third ink layer by directly ejecting ink onto the surface of the expandable sheet;
A surface flattening method comprising curing the third ink layer.

[Appendix 4]
In the surface planarization method according to attachment 3,
At least one of the first ink layer and the third ink layer is made of a single color ink that assists the color development of the second ink layer.

[Appendix 5]
In the surface planarization method according to attachment 2,
The surface flattening method according to claim 1, wherein the ink layer formed immediately below the second ink layer is made of a single color ink that assists color development of the second ink layer.

[Appendix 6]
In the surface planarization method according to attachment 1,
The first ink layer is formed by directly ejecting the ink onto the surface of the expandable sheet,
The method for planarizing a surface, wherein the second time is longer than the first time.

[Appendix 7]
A first ink layer is formed by ejecting a first ink on the surface side of the inflatable sheet that has been three-dimensionalized by expanding the surface;
Curing the first ink layer after elapse of a predetermined time from the formation of the first ink layer;
A second ink layer is formed by ejecting a second ink having a viscosity different from that of the first ink on the surface side of the expandable sheet on which the first ink layer is formed;
A method for planarizing a surface, comprising: curing the second ink layer after elapse of the same time as the predetermined time from the formation of the second ink layer.

[Appendix 8]
Layer forming means for forming ink layers by ejecting ink onto an inflatable sheet whose surface is expanded and three-dimensionalized;
Layer curing means for irradiating the ink layer with light to cure the ink layer;
A first ink layer that is the ink layer formed on the surface side of the expandable sheet by the layer forming unit; and the ink layer that is formed on the surface side of the expandable sheet by the layer forming unit. A surface flattening apparatus comprising: a control unit that controls the layer curing unit so that a time from layer formation to curing differs with a certain second ink layer.

[Appendix 9]
Layer forming means for forming ink layers by ejecting ink onto an inflatable sheet whose surface is expanded and three-dimensionalized;
Layer curing means for irradiating the ink layer with light to cure the ink layer;
A first ink layer that is the ink layer formed on the surface side of the expandable sheet by the layer forming unit; and the ink layer that is formed on the surface side of the expandable sheet by the layer forming unit. Control means for controlling the layer curing means so that the time from formation of the ink layer to curing is the same for a certain second ink layer,
The surface flattening device, wherein the viscosity of the first ink layer is different from the viscosity of the second ink layer.

DESCRIPTION OF SYMBOLS 1 Three-dimensional image forming apparatus 2 Black toner printing part 3 Thermal expansion process part 4 Inkjet printer part 5 Apparatus housing 6 Transfer belt 7, 31 Driving roller 8, 32 Followed roller 9 Image forming unit 11 Photosensitive drum 12 Developing roller 13 Toner container 14 Primary transfer roller 15 Secondary transfer roller 16 Image forming conveyance path 17 Recording medium 17a Resin 17b Thermal expansion microcapsule 18 Recording medium container 19 Fixing conveyance path 21 Fixing part 22 Heating roller 23 Pressing roller 24 Fixing part discharge roller pair 25 Media conveying path 26, 26a, 26b, 26c, 26d Conveying roller pair 27 Heat ray emitting unit 27a Halogen lamp 27b Reflector 30 Conveying unit 33 Conveying belts 34a, 34b Printer heads 35a, 35b Light source 45 CPU
46 I / F_CONT
47 PR_CONT
48 Image cutting part 49 Printer printing part 51 ROM
52 EEPROM
53 Operation Panel 54 Sensor Unit 55 Frame Memory 60, 61, 62 Ink Layer

Claims (9)

Forming a first ink layer by discharging ink to the surface side of the inflatable sheet that has been three-dimensionalized by expanding the surface;
Curing the first ink layer after a first time has elapsed since the formation of the first ink layer;
Ejecting ink onto the first ink layer on the surface side of the expandable sheet on which the first ink layer is formed to form a second ink layer;
A method for planarizing a surface, comprising: curing the second ink layer after a lapse of a second time different from the first time since the formation of the second ink layer. The surface flattening method according to claim 1,
The second ink layer is made of a color ink that colors the expandable sheet,
The method for planarizing a surface, wherein the first time is longer than the second time. In the surface planarization method according to claim 2, before Symbol third forming an ink layer by ejecting ink directly on the surface of the expandable sheet, curing the third ink layer,
The surface flattening method, wherein the first ink layer is formed on the third ink layer . The surface flattening method according to claim 3, wherein
At least one of the first ink layer and the third ink layer is made of a single color ink that assists the color development of the second ink layer. The surface flattening method according to claim 2,
The surface flattening method according to claim 1, wherein the ink layer formed immediately below the second ink layer is made of a single color ink that assists color development of the second ink layer. The surface flattening method according to claim 1,
The first ink layer is formed by directly ejecting the ink onto the surface of the expandable sheet,
The method for planarizing a surface, wherein the second time is longer than the first time. A first ink layer is formed by ejecting a first ink on the surface side of the inflatable sheet that has been three-dimensionalized by expanding the surface;
Curing the first ink layer after elapse of a predetermined time from the formation of the first ink layer;
A second ink having a viscosity different from that of the first ink is ejected onto the first ink layer on the surface side of the expandable sheet on which the first ink layer is formed. Forming a layer,
A surface flattening method, comprising: curing the second ink layer after elapse of the same time as the predetermined time from the formation of the second ink layer. Layer forming means for forming ink layers by ejecting ink onto an inflatable sheet whose surface is expanded and three-dimensionalized;
Layer curing means for irradiating the ink layer with light to cure the ink layer;
A first ink layer that is the ink layer formed on the surface side of the expandable sheet by the layer forming unit, and the first ink layer on the surface side of the expandable sheet by the layer forming unit. And a control means for controlling the layer curing means so that the time from the formation of the ink layer to the curing is different from that of the second ink layer, which is the ink layer formed on the ink layer. Surface flattening device. Layer forming means for forming ink layers by ejecting ink onto an inflatable sheet whose surface is expanded and three-dimensionalized;
Layer curing means for irradiating the ink layer with light to cure the ink layer;
A first ink layer that is the ink layer formed on the surface side of the expandable sheet by the layer forming unit, and the first ink layer on the surface side of the expandable sheet by the layer forming unit. A control means for controlling the layer curing means so that the time from the formation of the ink layer to the curing is the same with the second ink layer that is the ink layer formed on
The surface flattening device, wherein the viscosity of the first ink layer is different from the viscosity of the second ink layer.