Printing method

Abstract

To provide a printer which dries printed matters in a short time and enables reducing damage to the printed matters caused by heat, and to provide a printing method.SOLUTION: A printer includes: a printing part 20 which causes a conductive metallic paste 51 which absorbs light energy to adhere to a film-like base material 50 to form a printed matter 50b; and a dry part 30 which radiates the printed matter with light A emitted by an LED light emitting device 31 to cause the conductive metal paste 51 of the printed matter 50b to absorb the light energy and dry.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a printing apparatus and a printing method. [Background technology]

[0002] Known methods for drying a printed matter, which is a print object printed with a printing material such as ink, include the method described in Patent Document 1. In the method described in Patent Document 1, a pattern is printed on the surface of a substrate, which is the print object, using a photosinterable metal ink to form a printed matter, and then the printed matter is dried by placing the printed matter in an oven or irradiating it with infrared rays before the photosintering step. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2011-521055 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the method of drying the printed matter using an oven has the problem that it takes a long time to dry, and the method of drying the printed matter using an oven or infrared rays has the problem that the substrate of the printed matter may be damaged by heat.

[0005] This invention has been made to solve these problems, and its object is to provide a printing device and printing method that can dry printed materials in a short time and reduce damage to printed materials caused by heat. [Means for solving the problem]

[0006] In order to solve the above problems, the printing device of the present invention comprises a printing unit that forms a printed matter by attaching a printing material that absorbs light energy to a printing object, and a drying unit that irradiates the printed matter with light emitted from a light source, causing the printing material to absorb the light energy and dry the printing material.

[0007] The light source may also be an LED. The light emitted by the light source may be visible light. Furthermore, the illuminance on the printed surface of the printed matter when irradiated with light may be 5,000,000 Lx or more. In addition, the light source may be a linear light source in which multiple light-emitting elements are arranged in a line, and the minimum illuminance on the printed surface of the printed material in the direction in which the light-emitting elements of the linear light source are arranged when irradiating light may be 70% or more and less than 100% of the maximum illuminance. The printing apparatus may also have a photosintering unit that photosinters the dried printing material. The printer may also have an airflow generating section that generates an airflow between the light source and the printed material when drying the printing material.

[0008] In order to solve the above-mentioned problems, the printing method of the present invention includes a step of forming a print by adhering a printing material that absorbs light energy to a printing object, and a step of irradiating the print with light emitted from a light source to cause the printing material to absorb the light energy and dry the printing material. A printing method in which the light source is an LED, the light emitted by the light source is visible light, and the illuminance on the printed surface of the printed matter when irradiating the light is 5,000,000 Lx or more. .

[0009] The light source may also be an LED. The light emitted by the light source may be visible light. Furthermore, the illuminance on the printed surface of the printed matter when irradiated with light may be 5,000,000 Lx or more. In addition, the light source may be a linear light source in which multiple light-emitting elements are arranged in a line, and the minimum illuminance on the printed surface of the printed material in the direction in which the light-emitting elements of the linear light source are arranged when irradiating light may be 70% or more and less than 100% of the maximum illuminance. The temperature of the printed surface of the printed matter in the step of forming the printed matter may be 5°C or higher and 35°C or lower. Furthermore, a step of photosintering the printing material may be included after the step of drying the printing material. In addition, in the step of drying the printing material, an air flow may be generated between the light source and the printed material. [Effects of the Invention]

[0010] The printing device and printing method of this invention irradiate the printed matter with light emitted from a light source, causing the printing material to absorb the light energy and dry the printing material, thereby drying the printed matter in a short time and reducing heat damage to the printed matter. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a printing device according to a first embodiment; [Figure 2] FIG. 2 is a schematic view showing the inside of the drying unit shown in FIG. [Figure 3] 3 is a flowchart showing a printing method for printed matter in the first embodiment. [Figure 4] 1 is a schematic diagram of a printed matter according to a first embodiment. [Figure 5] FIG. 10 is a schematic view showing the inside of a drying unit according to a second embodiment. [Figure 6] 10 is a flowchart showing a printing method for printed matter according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Embodiment 1 A printing device and a printing method according to a first embodiment will be described below with reference to the accompanying drawings. 1 is a schematic diagram of a printing apparatus according to the present embodiment 1. The printing apparatus 1 includes a control unit 11 that controls the entire system, a printing unit 20 that prints a printing material on a substrate, a drying unit 30 that dries the printing material on the substrate that has been printed in the printing unit 20, and a light-sintering unit 40 that sinters the printing material that has been dried in the drying unit 30.

[0013] In addition, multiple rollers and reels are provided in various locations of the printing device 1, and the continuous, long film-like substrate 50 is fed, transported, or wound up, thereby transporting the film-like substrate 50 through the printing section 20, drying section 30, and photosintering section 40 in that order.

[0014] The film substrate 50 is a continuous, long, thin film substrate used for flexible substrates that form electronic circuits. This film substrate 50 is made of paper, polyethylene terephthalate (PET), polyimide (PI), or any other material, or any combination of these materials. The film substrate constitutes the object to be printed.

[0015] The printing unit 20 forms a print by screen-printing a conductive metal paste containing cuprous oxide for photosintering and a solvent onto the film-like substrate 50. The conductive metal paste constitutes the printing material.

[0016] The drying unit 30 has a light-emitting LED device inside, and irradiates light onto the film-like substrate 50 on which the conductive metal paste has been printed, thereby drying the conductive metal paste.

[0017] The light sintering unit 40 is a light sintering device that sinters the conductive metal paste on the film-shaped substrate 50 that has been dried in the drying unit 30 , thereby adhering the conductive metal paste to the film-shaped substrate 50 .

[0018] FIG. 2 is a schematic diagram showing the interior of the drying unit 30. An LED light-emitting device 31 having a light-emitting unit 32 is provided at the vertically upper side of the interior of the drying unit 30. The light-emitting unit 32 is formed by arranging multiple LEDs constituting light emitters in a straight line vertically below the LED light-emitting device 31, and irradiates light A vertically downward. The light A irradiated by the light-emitting unit 32 is preferably visible light. The wavelength of this visible light is 360 nm or more and 830 nm or less. The wavelength of the light A irradiated by the light-emitting unit 32 is more preferably 400 nm or more and 800 nm or less. The LED light-emitting device 31 constitutes a linear light source.

[0019] A film-like substrate 50 is disposed vertically below the LED light-emitting device 31. The film-like substrate 50 is fed by a feed roller 33 from the upstream printing unit 20 (see FIG. 1 ) to the downstream photosintering unit 40, i.e., in the direction of arrow B. The film-like substrate 50 is disposed such that the printed surface 50a, on which the conductive metal paste 51 is printed in the printing unit 20, faces the light-emitting unit 32 of the LED light-emitting device 31. The LED light-emitting device 31 is disposed such that the angle X formed between the direction of light A emitted from the light-emitting unit 32 and the printed surface 50a below the light-emitting unit 32 in the vertical direction is 90 degrees. The distance between the light-emitting unit 32 and the printed surface 50a below the light-emitting unit 32 in the vertical direction is preferably 1 mm or more and 50 cm or less. Furthermore, the illuminance of the printed surface 50a below the light-emitting unit 32, i.e., the illuminance of the printed matter 50b illuminated by the light-emitting unit 32, is preferably 5,000,000 Lx or more.

[0020] Furthermore, since the light-emitting unit 32 of the LED light-emitting device 31 has multiple LEDs arranged in a straight line, when light A is irradiated onto the printed surface 50a of the printed matter 50b, a region of the printed surface 50a irradiated with light A is generated along the linear direction of the LEDs. To ensure a uniform illuminance distribution in this region of the printed surface 50a, the angle X formed between the direction of irradiation of light A from the light-emitting unit 32 of the drying unit 30 and the printed surface 50a, and the distance from the light-emitting unit 32 to the printed surface 50a are determined. As described above, in the first embodiment, the LED light-emitting device 31 is arranged so that the angle X is 90 degrees. The angle X and the distance from the light-emitting unit 32 to the printed surface 50a are preferably determined so that the minimum illuminance value on the printed surface 50a in the direction in which the LEDs are arranged is 70% or more and less than 100% of the maximum illuminance value. More preferably, the minimum illuminance value on the printed surface 50a in the direction in which the LEDs are arranged is 80% or more and less than 100% of the maximum illuminance value.

[0021] Next, a method for printing a printed matter using the printing device 1 of the first embodiment will be described. 3 is a flowchart showing the printing method for printed matter in the present embodiment 1. In step S1 of the printing method for printed matter in the present embodiment 1, a yellow-brown conductive metal paste to be printed on film-like substrate 50 (see FIG. 3) is prepared by a known conductive metal paste preparation means (not shown). This conductive metal paste is supplied to printing unit 20 shown in FIG.

[0022] Next, in step S2, the printing unit 20 forms a print by screen-printing the conductive metal paste onto the printing surface 50a (see FIG. 2) of the film-like substrate 50 transported to the printing unit 20. Note that the temperature of the printing surface 50a at this time is room temperature, specifically, 5°C or higher and 35°C or lower.

[0023] 4 is a schematic diagram of a printed matter 50b formed by printing conductive metal paste 51 on a film-like substrate 50 by printing unit 20. Printed matter 50b has a conductor pattern 52 formed on a printing surface 50a by conductive metal paste 51. Note that conductor pattern 52 in the first embodiment is merely an example and is not limited thereto, and any conductor pattern required for other flexible substrates may be formed thereon.

[0024] Next, in step S3 shown in Fig. 3, the film-like substrate 50 is sent from the printing unit 20 (see Fig. 1) to the drying unit 30 as shown in Fig. 2. Then, when the printed matter 50b on the film-like substrate 50 is positioned directly under the light-emitting unit 32 of the LED light-emitting device 31, light A is irradiated from the light-emitting unit 32 of the LED light-emitting device 31 once for a predetermined period of time.

[0025] When light A is irradiated onto printed matter 50b, yellowish-brown conductive metal paste 51 forming conductor pattern 52 (see FIG. 4) absorbs light A, and heat is generated by the energy of light A. This generated heat evaporates components such as the solvent contained in conductive metal paste 51, causing conductive metal paste 51 to dry.

[0026] As described above, the light emitted by the light-emitting unit 32 of the LED light-emitting device 31 is preferably visible light. The wavelength of this visible light is 360 nm or more and 830 nm or less. Furthermore, the wavelength of the light A emitted by the light-emitting unit 32 is more preferably 400 nm or more and 800 nm or less. When the light A is visible light, the heat generation efficiency when the light A hits the conductive metal paste 51 is improved, and the heat generation when the light A hits the film-like substrate 50 is suppressed, thereby suppressing damage to the film-like substrate 50 due to heat. When the wavelength of the light A emitted by the light-emitting unit 32 is 400 nm or more and 800 nm or less, damage to the film-like substrate 50 due to heat can be further suppressed.

[0027] As described above, the distance between the light-emitting unit 32 of the LED light-emitting device 31 and the printed surface 50a is preferably 1 mm or more and 50 cm or less. When the printed matter 50b is irradiated with light A, the components contained in the conductive metal paste 51 evaporate and may scatter due to rapid heating. By setting the distance between the light-emitting unit 32 and the printed surface 50a to 1 mm or more, it is possible to prevent the scattered or evaporated components of the conductive metal paste 51 from adhering to and contaminating the light-emitting unit 32. Furthermore, by setting the distance between the light-emitting unit 32 and the printed surface 50a to 50 cm or less, it is possible to ensure that the illuminance on the printed surface 50a is sufficient to dry the conductive metal paste 51 of the printed matter 50b.

[0028] As described above, it is preferable that the angle X formed between the direction of irradiation of light A from the light-emitting section 32 of the LED light-emitting device 31 and the printed surface 50a is 90 degrees. When the angle X is 90 degrees, the irradiation efficiency of light A is improved, and the illuminance on the printed surface 50a can be made sufficient to dry the conductive metal paste 51 of the printed matter 50b.

[0029] Furthermore, because the LEDs of the light-emitting unit 32 of the LED light-emitting device 31 are arranged in a straight line, the illuminance distribution of the light A on the printed surface 50a may become large depending on the position of the light-emitting unit 32 and the distance between the light-emitting unit 32 and the printed surface 50a, which may cause uneven drying of the printed surface 50a. Such uneven drying of the printed surface 50a may cause the conductive metal paste 51 to scatter.

[0030] On the other hand, in the first embodiment, the LED light-emitting device 31 is disposed relative to the film-like substrate 50 such that the angle X and the distance from the light-emitting portion 32 to the printed surface 50a result in a uniform illuminance distribution on the printed surface 50a. Furthermore, the LED light-emitting device 31 is disposed relative to the film-like substrate 50 such that the minimum illuminance in the direction in which the LEDs on the printed surface 50a are arranged is preferably 70% or more and less than 100% of the maximum, and more preferably 80% or more and less than 100% of the maximum, in the direction in which the LEDs on the printed surface 50a are arranged. This reduces the illuminance distribution of the light A on the printed surface 50a, thereby preventing uneven drying across the printed surface 50a and preventing scattering of the conductive metal paste.

[0031] As described above, the illuminance on the printing surface 50a vertically below the light-emitting unit 32 is preferably 5,000,000 Lx or more. In other words, the illuminance on the printing surface 50a is preferably 5,000,000 Lx or more by appropriately setting the intensity and wavelength of light A emitted from the LED light-emitting device 31, the distance between the light-emitting unit 32 and the printing surface 50a, the angle X, and other factors. In this case, by setting the irradiation time of light A from the LED light-emitting device 31 to approximately 10 seconds or less and irradiating it once, sufficient heat is generated in the conductive metal paste 51, allowing the conductive metal paste 51 to dry within approximately 10 seconds. Furthermore, by setting the irradiation time of light A from the LED light-emitting device 31 to approximately 10 seconds or less, thermal damage to the film-like substrate 50 and the conductive metal paste 51 can be reduced.

[0032] Furthermore, the irradiation time of light A by the LED light-emitting device 31 is not limited to this, but should be set appropriately based on the intensity and wavelength of light A irradiated from the LED light-emitting device 31, the distance between the light-emitting part 32 and the printing surface 50a, the angle X, the type of printing object and substrate, etc.

[0033] In known prior art, in order to facilitate drying of the ink printed on the printing surface of the printed matter, a method has been used in which the printing surface is heated in advance by irradiating the printing surface with infrared light or other light immediately before the step of forming the printed matter. On the other hand, in the present embodiment 1, by irradiating light A using the LED light emitting device 31, the conductive metal paste 51 can be dried by the drying unit 30 from a room temperature state without preheating the printing surface 50a of the printed matter 50b, which has the advantage that a step of heating the printed matter immediately before the step of forming the printed matter is not required and a separate heating means for heating the printed matter is not required.

[0034] Next, the film-like substrate 50 is sent in the direction of arrow B to the photosintering unit 40. Next, in step S4 shown in FIG. 3, the photosintering unit 40 (see FIG. 1) photosinters the dried conductive metal paste 51 of the printed matter 50b. This causes the conductive metal paste 51 to adhere to the film-like substrate 50, and a conductor pattern 52 (see FIG. 4) is formed stably on the film-like substrate 50. Next, the film-like substrate 50 is cut to a predetermined length by a cutting device (not shown), and a flexible substrate having the conductor pattern 52 is obtained.

[0035] As described above, the printing device according to the first embodiment comprises a printing unit 20 that forms a printed matter 50b by applying a conductive metal paste 51 that absorbs light energy to a film-like substrate 50, and a drying unit 30 that irradiates the printed matter 50b with light A emitted by an LED light-emitting device 31, causing the conductive metal paste 51 to absorb the light energy and dry the conductive metal paste 51. This allows the printed matter to dry in a short time, reducing damage to the printed matter caused by heat.

[0036] Furthermore, the printing method according to the first embodiment thus includes step S2 of forming a printed matter 50b by adhering a conductive metal paste 51 that absorbs light energy to a film-like substrate 50, and step S3 of irradiating the printed matter 50b with light A emitted by the LED light-emitting device 31 to cause the conductive metal paste 51 to absorb the light energy and dry the conductive metal paste 51, thereby enabling the printed matter to dry in a short time and reducing damage to the printed matter due to heat.

[0037] Furthermore, since the light source of the printing device according to the first embodiment is the LED light emitting device 31, the light A with sufficient illuminance can be irradiated onto the printed matter on the printing surface 50a.

[0038] Furthermore, since the light A irradiated in this embodiment 1 is visible light, the efficiency of heat generation when the light A hits the conductive metal paste 51 is improved, and the heat generation when the light A hits the film-like substrate 50 is suppressed, thereby suppressing thermal damage to the film-like substrate 50.

[0039] Furthermore, in this embodiment 1, the illuminance on the printed surface 50a of the printed matter 50b when irradiated with light A is 5,000,000 Lx or more, so the irradiation time of light A can be shortened and the occurrence of thermal damage to the film-like substrate 50 and the conductive metal paste 51 can be reduced.

[0040] Furthermore, the LED light-emitting device 31 is a linear light source in which multiple light-emitting bodies are arranged in a line, and when light A is emitted, the minimum illuminance in the direction in which each LED of the LED light-emitting device 31 is arranged on the printed surface 50a of the printed matter 50b is 70% or more and less than 100% of the maximum value, thereby preventing uneven drying depending on the position on the printed surface 50a and preventing the conductive metal paste 51 from scattering due to uneven drying.

[0041] Furthermore, since the temperature of the printed surface of the printed matter 50b in the step of forming the printed matter 50b is 5° C. or higher and 35° C. or lower, there is no need for a step of heating the printed matter immediately before the step of forming the printed matter.

[0042] The printing apparatus according to the first embodiment also includes a light-sintering unit 40 that light-sinters the dried conductive metal paste 51. Furthermore, the printing method according to the first embodiment also includes a step S4 of light-sintering the conductive metal paste 51 after a step S3 of drying the conductive metal paste 51. Therefore, the drying and light-sintering of the conductive metal paste 51 can be performed continuously in a short time.

[0043] Embodiment 2 Next, a second embodiment will be described. In the second embodiment, the same reference numerals as those in Figures 1 to 4 of the first embodiment denote the same or similar components, and detailed description thereof will be omitted. In the second embodiment, the drying section 30 has an airflow generating device in comparison with the first embodiment.

[0044] FIG. 5 is a schematic diagram showing the inside of the drying section 30 of the second embodiment. The drying section 30 is provided with an airflow generating device 60. The airflow generating device 60 is connected to the inside of the drying section 30 by a communication pipe 61. The tip of the communication pipe 61 is directed between the LED light-emitting device 31 and the printing surface 50a. The airflow generating device 60 can be any airflow generating device, such as a device that generates airflow using a fan. The other configurations are the same as those of the first embodiment.

[0045] Next, the operation of the printing device of the second embodiment will be described. Fig. 6 is a flowchart showing a printing method for a printed matter of the second embodiment. After the conductive paste is printed on the film-like substrate 50 in step S2, the airflow generating device 60 shown in Fig. 5 generates an airflow C in step S5. This airflow C is sent out from the communication pipe 61 and passes between the LED light-emitting device 31 and the film-like substrate 50. In other words, the airflow generating device 60 generates the airflow C between the LED light-emitting device 31 and the film-like substrate 50.

[0046] At this time, the gas flowing as the air current C is preferably a gas that is unlikely to affect the film-like substrate 50 and the conductive metal paste 51, and is preferably a gas such as air. Furthermore, more preferable examples of the gas flowing as the air current C include inert gases such as nitrogen, argon, and helium.

[0047] Next, step S3 (see FIG. 6) is performed, and light A is irradiated onto the printed matter 50b on the film-like substrate 50. Because airflow C is generated while light A is irradiating the printed matter 50b, the vapor generated when the conductive metal paste 51 is heated by light A is expelled by the airflow C from between the LED light-emitting device 31 and the film-like substrate 50. In addition, airflow C improves the rate at which the temperature of the printed matter 50b decreases after irradiation with light A, thereby reducing damage to the film-like substrate 50 due to heat. Next, after irradiation of light A by the LED light-emitting device 31 is completed, generation of airflow C by the airflow generating device 60 is stopped. Other operations are the same as those in embodiment 1.

[0048] As described above, the printing apparatus according to the second embodiment includes an airflow generating device 60 that generates an airflow between the LED light emitting device 31 and the printed matter when drying the conductive metal paste 51. The printing method according to the second embodiment also includes a step S5 that generates an airflow between the LED light emitting device 31 and the printed matter in the step S2 that dries the conductive metal paste 51. This allows steam that is generated when the conductive metal paste 51 dries to be quickly discharged, preventing contamination of the light emitting section 32 of the LED light emitting device 31.

[0049] In addition, although the airflow generating device 60 in this embodiment 2 is connected to the inside of the drying section 30 by a connecting pipe 61, the airflow generating device 60 may be provided inside the drying section 30 and may not have a connecting pipe 61.

[0050] Next, modifications of the first and second embodiments will be described. In the first and second embodiments, the LED light-emitting device 31 is positioned so that the angle X (see FIGS. 2 and 5) between the direction of light A emitted from the light-emitting unit 32 and the printed surface 50a is 90 degrees, which is the most preferable angle. However, the angle X may be an angle other than 90 degrees as long as the light A can irradiate the printed matter 50b on the printed surface 50a with sufficient illuminance to evaporate the solvent in the conductive metal paste 51. In this case, the angle X is preferably between 30 degrees and 150 degrees to ensure the necessary illuminance on the printed matter 50b. This allows the vapor generated when the conductive metal paste 51 on the printed matter 50b evaporates to be efficiently diffused into the surrounding air, preventing the vapor from accumulating.

[0051] Furthermore, in the first and second embodiments, the angle X formed between the direction of irradiation of light A from the light-emitting unit 32 and the printed surface 50a is constant, but the LED light-emitting device 31 or the light-emitting unit 32 may be moved or rotated during irradiation of light A to vary the angle X. This allows the vapor generated when the conductive metal paste 51 of the printed matter 50b evaporates due to the movement or rotation of the LED light-emitting device 31 or the light-emitting unit 32 to be efficiently diffused into the surrounding air, preventing the vapor from accumulating.

[0052] In addition, in embodiments 1 and 2, an LED light-emitting device 31 is used as the light source for the drying section 30, but any light source, such as a mercury lamp or a halogen lamp combined with a lens, may be used instead of the LED light-emitting device 31 as long as it can irradiate the printing surface 50a with sufficient illuminance.

[0053] In addition, in the first and second embodiments, when the printed matter 50b of the film-like substrate 50 is positioned directly below the light-emitting unit 32 of the LED light-emitting device 31, the light A is emitted from the light-emitting unit 32 of the LED light-emitting device 31 once for a predetermined time. However, the method of emitting light A is not limited to this. For example, the LED light-emitting device 31 may emit light A two or more times for a total predetermined time, or the light-emitting unit 32 may be blinked to emit light A in pulses. Furthermore, when the LED light-emitting device 31 emits light A two or more times, the intensity of light A may be reduced in the first irradiation and gradually increased in the second and subsequent irradiations, or the intensity of light A may be increased in the first irradiation and gradually increased in the second and subsequent irradiations. This suppresses a rapid increase in the temperature of the conductive metal paste 51 compared to when light A is emitted only once for a predetermined time, and suppresses contamination of the surroundings of the printed matter 50b due to evaporation or scattering of components of the conductive metal paste 51.

[0054] Furthermore, in the first and second embodiments, a continuous, elongated film substrate 50 is used as the printing object, but this is not limited thereto, and any printing object can be used. For example, instead of a continuous, elongated film substrate, a film substrate cut into a rectangular shape may be used as the printing object, or a rigid substrate may be used. Furthermore, the printing object is not limited to the substrate of an electronic circuit, and may be paper, film, plate-shaped resin member, or other form of member used for other general purposes. Note that in the first and second embodiments, it is preferable to use a film-shaped or plate-shaped printing object.

[0055] In addition, in the first and second embodiments, the film-like substrate 50, which is the object to be printed, is transported in the direction of arrow B shown in Figures 2 and 5 by the feed roller 33, but the object to be printed may be fixed and the LED light-emitting device 31 may be moved to irradiate light A from directly above the printed matter on the object to be printed.

[0056] Furthermore, in the first and second embodiments, a yellowish-brown conductive metal paste 51 containing cuprous oxide for photosintering and a solvent is printed as the printing member. However, the printing member is not limited to this, and any printing member having a color capable of absorbing light A and generating heat may be used. For example, conductive metal pastes in black, brown, gray, blue, red, green, and dark colors thereof may be used as the printing member. Furthermore, the metal contained in the conductive metal paste may be any conductive metal, such as copper or silver. Furthermore, the printing member is not limited to the conductive metal paste. A conductive nanoink may be used as long as it has a color capable of absorbing light A and generating heat, as described above. Furthermore, pastes, inks, paints, and other printing members commonly used in printing may be used, even if they do not contain conductive materials capable of forming electronic circuits.

[0057] Furthermore, in the first and second embodiments, there is a space between the light-emitting unit 32 and the printed surface 50a, but a cover made of transparent glass, a transparent resin film, or other transparent material may be provided between the light-emitting unit 32 and the printed surface 50a as long as it does not significantly reduce the illuminance of the printed surface 50a when irradiated with light A. This prevents the conductive metal paste 51 of the printed matter 50b from evaporating and scattering, thereby adhering to and contaminating the light-emitting unit 32.

[0058] Furthermore, in the first and second embodiments, the printing unit 20 screen-prints the conductive metal paste 51 onto the film-like substrate 50, but the type of printing on the film-like substrate 50 is not limited to this, and any method that can be used, for example, flexographic printing, gravure printing, gravure offset printing, inkjet printing, and other methods that can deposit paste or ink onto the substrate surface, can be used. [Explanation of symbols]

[0059] 20 printing unit, 30 drying unit, 31 LED light emitting device (light source), 40 light sintering unit, 50 film-like substrate (printing object), 50a printing surface, 50b printed matter, 51 conductive metal paste (printing material), 60 airflow generating device (airflow generating unit), A light, C airflow.

Claims

1. A step of forming a print by attaching a printing material that absorbs light energy to a print target; a step of irradiating a printed surface of the printed matter with light emitted from a light source, causing the printing material to absorb light energy and dry the printing material; A printing method comprising: the light source is an LED; the light emitted by the light source is visible light, A printing method, wherein the illuminance on the printed surface of the printed matter when irradiating the light is 5,000,000 Lx or more.

2. The light source is a linear light source in which a plurality of light-emitting elements are arranged in a line, 2. The printing method according to claim 1, wherein the minimum illuminance on the printed surface of the printed matter in the direction in which the light-emitting element of the linear light source is arranged when the light is irradiated is 70% or more and less than 100% of the maximum illuminance.

3. 3. The printing method according to claim 1, wherein the temperature of the printing surface of the printed matter in the step of forming the printed matter is 5° C. or higher and 35° C. or lower.

4. The printing method according to any one of claims 1 to 3, further comprising a step of photosintering the printing material after the step of drying the printing material.

5. 5. The printing method according to claim 1, wherein an air flow is generated between the light source and the printed matter in the step of drying the printing material.

Images