WO2020129568A1

WO2020129568A1 - Printing device and printing method

Info

Publication number: WO2020129568A1
Application number: PCT/JP2019/046621
Authority: WO
Inventors: 大西　勝
Original assignee: 株式会社ミマキエンジニアリング
Priority date: 2018-12-19
Filing date: 2019-11-28
Publication date: 2020-06-25
Also published as: JP7098516B2; JP2020097192A

Abstract

[Problem] To properly perform high-quality printing on various media. [Solution] A printing device 10 that performs printing on a medium 50 is provided with: an inkjet head 102 that is an ejection head; an ultraviolet-ray light source 104 that is an energy-ray irradiation unit; and an infrared-ray heater 26 that is a post-heating means. Ink is ink that generates heat when absorbing ultraviolet rays irradiated from the ultraviolet-ray light source 104, and includes a color material, a heat fixing resin, and a solvent. The ultraviolet-ray light source 104 vaporizes at least part of the solvent included in the ink by irradiating the ink attached to the medium 50 with ultraviolet rays. The infrared-ray heater 26 fixes the heat fixing resin to the medium together with the color material by heating the ink.

Description

Printing device and printing method

The present invention relates to a printing device and a printing method.

Conventionally, as an ink for inkjet printers, an evaporation drying type ink that is fixed on a medium by evaporating a solvent has been widely used. Further, in recent years, as the evaporation type ink, an ink (instantaneous drying type ink) in which the ink itself generates heat by irradiation with energy rays such as ultraviolet rays has been proposed (for example, see Patent Document 1). When such an instant dry type ink is used, for example, by irradiating the ink on the medium with energy rays immediately after landing on the medium, a short time may occur before ink bleeding (between colors, etc.) occurs. The ink can be dried efficiently in time.

International Publication No. 2017/135425

Instant flash ink is a new type of ink developed in recent years. Therefore, it is desired to carry out further various studies on the constitution and usage of the instant dry type ink. Further, in this case, for various uses, it is desired to use an instant dry type ink having a structure suitable for the use. Therefore, an object of the present invention is to provide a printing apparatus and a printing method that can solve the above problems.

The inventor of the present application has conducted earnest research on the use of instant dry ink in various application fields. Then, in this earnest research, it was considered to use an instant dry type ink in a field where coating was conventionally performed by a powder coating method (powder coating). In this case, the powder coating method is, for example, a coating method of electrostatically adhering the powder to the object to be coated by spraying the powder from the spray to the object to be coated with compressed air. That is. The powder coating method can be considered as, for example, an electrostatic coating method in which powder is electrostatically attached. Further, in the powder coating method, by heating the object to be coated after adhering the powder, the powder is heated and melted to form a film. The powder coating method does not require the use of an organic solvent (VOC-free), can coat uneven or three-dimensional objects, and has excellent fastness. Therefore, it is used for coating various objects to be used indoors or outdoors. More specifically, for example, in the past, household appliances, road materials, and many other industrial products have been widely coated with the powder coating method.

However, the conventional powder coating method was usually used for filling with a single color. This is because, in the case of the powder coating method, the area where the powder adheres is large due to the configuration of spraying the powder, and it is difficult to draw a high-definition image or a full-color image. Further, when the powder coating method is used, it is usually necessary to prepare a working environment and take safety measures in order to prevent the powder from scattering and preventing electric shock due to the use of high voltage. Therefore, there is also a problem that much cost and time are required for preparation before painting.

On the other hand, the inventor of the present application uses the same or similar material as the object to be coated, which has been conventionally coated by the powder coating method, as the medium to be printed, and uses the ink of the instant drying type, It has been found that printing can be performed on. Further, in this case, the powder coating method is performed by using ink containing a predetermined heat-fixing resin and sufficiently heating the ink adhering to the medium, rather than simply using the instant-drying type ink. It has been found that the ink can be fixed to the medium in a state of having a high fastness as high as required in the field.

Then, the inventor of the present application discovered the features necessary for obtaining such effects by further earnest research, and arrived at the present invention. In order to solve the above problems, the present invention is a printing apparatus that prints on a medium, including an ejection head that ejects ink onto the medium, and an energy beam irradiation unit that irradiates the medium with energy beams. A post-heating means for heating the ink after being irradiated with energy rays by the energy ray irradiating section, wherein the ink is ink that generates heat by absorbing the energy rays emitted by the energy ray irradiating section. And a color material, a heat-fixing resin that is a resin that is fixed to the medium by being heated by the post-heating means, and a solvent, and the energy ray irradiating unit is attached to the ink attached to the medium. At least a part of the solvent in the ink is evaporated by irradiating with energy rays, and the post-heating means fixes the heat fixing resin together with the coloring material on the medium by heating the ink. The printing device is configured to be.

According to the present invention, it is possible to appropriately print on various media.

In a printing apparatus according to one aspect of the present invention,
The post-heating unit heats the ink to form a film of the heat-fixing resin on the medium, and fixes the heat-fixing resin together with the coloring material on the medium.

According to the present invention, the ink can be fixed to the medium more appropriately.

In a printing apparatus according to one aspect of the present invention,
The thermosetting resin is a thermoplastic resin. The post-heating means heats the ink until the heat-fixing resin is dissolved so that the heat-fixing resin cooled after the heating by the post-heating means is fixed to the medium. Heating the ink.

According to the present invention, the ink can be properly fixed on the medium.

In a printing apparatus according to one aspect of the present invention,
The thermosetting resin is a thermosetting resin. The post-heating means heats the ink until the heat-fixing resin is cured so that the heat-fixing resin cooled after the heating by the post-heating means is fixed to the medium. Heating the ink.

In a printing apparatus according to one aspect of the present invention,
The post-heating unit is a heater that heats the ink through the medium by heating the medium, and heats the medium such that the temperature of the medium becomes at least 80°C.

According to the present invention, heating for fixing the heat-fixing resin on the medium can be performed reliably and appropriately.

In a printing apparatus according to one aspect of the present invention,
The energy ray irradiating unit heats the ink so that the temperature of the ink on the medium does not exceed the boiling point of the solvent, and the post-heating means sets the temperature of the ink on the medium to the boiling point of the solvent. The ink is heated so as to reach a temperature of more than.

According to the present invention, it is possible to appropriately prevent bumping or the like of ink during heating in the energy ray irradiation section. Further, the ink can be appropriately and sufficiently heated during the heating by the post-heating means.

According to the present invention, high-quality printing can be appropriately performed on various media.

FIG. 1 is a diagram showing a printing device 10 according to this embodiment. FIG. 3 is a diagram showing a configuration of ink according to the present embodiment. FIG. 6 is a diagram showing a printing operation of the printing device 10. FIG. 3 is a diagram showing a configuration of ink according to the present embodiment. It is a figure which shows the further modification of the structure of ink. It is a figure which shows the printing apparatus 10A concerning a 1st modification. It is a figure which shows an example of a structure of the thermostat 32 used as a post-heating means.

Hereinafter, the present embodiment will be described with reference to the drawings. FIG. 1 shows a printing device 10 according to this embodiment. FIG. 1A is a simplified top view showing an example of a configuration of a main part of the printing apparatus 10. FIG. 1B is a side sectional view showing a simplified example of the configuration of the main part of the printing apparatus 10.

Note that the printing apparatus 10 may have the same or similar characteristics as a known printing apparatus except for the points described below. For example, the printing apparatus 10 may further include various configurations that are the same as or similar to known printing apparatuses in addition to the configurations described below. In addition, in the present embodiment, the printing apparatus 10 uses, for example, the same or similar material to be coated, which has been conventionally coated by the powder coating method, as a medium to be printed. Further, as can be understood from the following description and the like, the medium 50 may be a medium which is difficult to be coated by the conventional powder coating.

In the present embodiment, the printing apparatus 10 is an inkjet printer that prints on a medium 50 by an inkjet method, and includes a head unit 12, a platen 14, a guide rail 16, a scan drive unit 18, a print heater 20, a preheater 22, and an after-sales printer. The heater 24, the infrared heater 26, and the control unit 30 are provided.

The head portion 12 is a portion that ejects ink onto the medium 50. In addition, in the present embodiment, the head unit 12 is an example of an instant-drying type printing unit, and includes a plurality of inkjet heads 102c to 102k, which eject inks of different colors, and a plurality of ultraviolet light sources 104. .. The inkjet heads 102c to 102k are examples of ejection heads and eject color inks of respective colors for color printing. Further, more specifically, the inkjet head 102c ejects cyan (C color) ink. The inkjet head 102m ejects magenta (M) color ink. The inkjet head 102y ejects yellow (Y) ink. The inkjet head 102k ejects black (K) ink. Further, as shown in FIG. 1A, the inkjet heads 102c to 102k are aligned in the X direction (X axis direction) and arranged side by side in the Y direction (Y axis direction) orthogonal to the X direction. It In this case, the X direction is a direction parallel to the sub scanning direction in which the head unit 12 is moved relative to the medium 50 during the sub scanning operation described later. The Y direction is a direction parallel to the main scanning direction in which the head unit 12 is moved relative to the medium 50 during the main scanning operation. The main scanning operation is, for example, an operation of ejecting ink while moving in the main scanning direction.

Further, in the present embodiment, as the ink ejected from the inkjet heads 102c to 102k, an instantaneous dry type ink (instantaneous dry type liquid) that is a liquid that generates heat by being irradiated with energy rays is used. The instant dry type ink is, for example, an ink which itself generates heat when irradiated with energy rays. The fact that the ink itself generates heat due to the irradiation of energy rays means, for example, that the temperature of the entire ink rises because any component in the ink absorbs the energy rays. Further, in the present embodiment, ultraviolet rays (UV light) emitted from the ultraviolet light source 104 are used as such energy rays.

In addition, in the present embodiment, the ink ejected from the inkjet heads 102c to 102k contains at least a coloring material of each color, a heat fixing resin, and a solvent. In this case, the color material is, for example, a substance showing the color of ink. The heat-fixing resin is, for example, a resin that is fixed on the medium 50 by being heated at a predetermined temperature or higher. In the present embodiment, as the heat fixing resin, a resin that is fixed to the medium 50 by being heated by the infrared heater 26 is used. The solvent is a liquid component that dissolves or disperses other components in the ink. In addition to the above, the ink of each color may further include the same or similar component as a known ink (for example, a known instant drying type ink). The characteristics of the ink used in this embodiment will be described in more detail later.

The ultraviolet light source 104 is an example of an energy ray irradiation unit that irradiates the medium 50 with energy rays, and irradiates the ink of each color attached to the medium 50 with ultraviolet rays, which is an example of energy rays. As the ultraviolet light source 104, for example, a UVLED that is an LED that emits ultraviolet light can be preferably used. In this case, the ultraviolet light source 104 can be considered to be, for example, a UV LED instant drying unit or a UV instant drying unit. As the UVLED constituting the ultraviolet light source 104, for example, a known high-output UVLED having a central wavelength of light emission of about 360 to 390 nm (for example, 356 nm or 385 nm) can be preferably used. Further, each of the ultraviolet light sources 104 may be composed of, for example, a plurality of UVLEDs. In this case, a plurality of UVLEDs are arranged side by side so that a uniform irradiation distribution can be obtained with the required intensity within the print width, which is the width in the sub-scanning direction of the area where ink is ejected in each main scanning operation. It is possible to set it up.

Further, in the present embodiment, each of the plurality of ultraviolet light sources 104 is arranged on each of the one side and the other side in the main scanning direction with respect to the arrangement of the inkjet heads 102c to 102k, as shown in FIG. To be done. Further, the ultraviolet light source 104 radiates ultraviolet rays to heat the ink on the medium 50 to evaporate at least a part of the solvent in the ink. In this case, evaporating at least a part of the solvent in the ink means evaporating at least a part of the solvent so that the ink is sufficiently dried, for example, according to the required print quality and the like. Further, in the present embodiment, the ultraviolet light source 104 irradiates the ink on the medium 50 with ultraviolet rays to evaporate at least a part of the solvent, so that the medium 50 is heated before being heated by the infrared heater 26 or the like. The viscosity of the ink is increased to a viscosity at which bleeding does not occur. The fact that no bleeding occurs on the medium 50 means that no bleeding, which is a problem in the quality required for printing, occurs. In this case, for example, even when a medium 50 that causes a problem of bleeding when using a normal evaporative drying type ink (for example, an evaporative drying type ink other than the instant drying type ink), the bleeding is appropriately performed. Can be suppressed. Further, even when a plurality of colors of ink are used, it is possible to appropriately suppress ink bleeding. Therefore, as in the present embodiment, a plurality of inkjet heads (inkjet heads 102c to 102k) that eject inks of different colors are used. ), it is possible to perform color printing (for example, full-color printing). Therefore, according to this embodiment, for example, high-quality printing (for example, high-definition printing) can be appropriately performed on various media 50.

As shown in FIG. 1B, the platen 14 is a base member that supports the medium 50, and supports the medium 50 while facing the head unit 12. In addition, in the present embodiment, the platen 14 houses the print heater 20, the preheater 22, and the afterheater 24 inside. The guide rail 16 is a rail member that guides the movement of the head unit 12 during the main scanning operation.

The scan driving unit 18 is a driving unit that causes the head unit 12 to perform a main scanning operation and a sub scanning operation. In this case, to cause the head unit 12 to perform the main scanning operation and the sub-scanning operation means to cause the inkjet heads 102c to 102k in the head unit 12 to perform the main scanning operation and the sub-scanning operation. During the main scanning operation, the scan driving unit 18 causes the inkjet heads 102c to 102k to eject ink according to the image to be printed, while moving the head unit 12 along the guide rail 16, for example.

Further, in the present embodiment, the scan driving unit 18 further drives the ultraviolet light source 104 in the head unit 12. In addition, the scan driver 18 causes the head unit 12 to perform the main scanning operation in both (one) and the other (both) directions in the main scanning direction. Then, in this case, the ultraviolet light source 104 is driven so that the ultraviolet light source 104 located on the rear side of the inkjet heads 102c to 102k in the moving direction during the main scanning operation irradiates the ink on the medium 50 with ultraviolet light. With this configuration, for example, the ink immediately after landing on the medium 50 can be appropriately irradiated with ultraviolet rays. Further, depending on the quality required for printing, it may be possible to irradiate the ultraviolet light source 104 with ultraviolet light after a certain time has elapsed since the ink has landed on the medium 50. In this case, for example, it is conceivable to adjust the time until the irradiation of ultraviolet rays by appropriately changing the positional relationship between the inkjet heads 102c to 102k in the head unit 12 and the ultraviolet light source 104.

Further, the scan driving unit 18 changes the area of the medium 50 facing the head unit 12 by driving the sub-scanning operation between main scanning operations. In this case, the sub-scanning operation is, for example, an operation of moving in the sub-scanning direction relative to the medium 50. The scan driving unit 18 drives the sub-scanning operation by driving a roller or the like (not shown) to move the medium 50 in the transport direction (media transport direction) parallel to the sub-scanning direction.

The print heater 20, preheater 22, and afterheater 24 are heating means for heating the medium 50. Of these, the print heater 20 is a heater that heats the medium 50 at a position facing the head unit 12. By using the print heater 20, for example, the ink on the medium 50 can be heated more efficiently. Further, in this case, the configuration of the printing apparatus 10 of the present embodiment can be considered as a configuration in which the ultraviolet light source 104 and the print heater 20 are used together to dry the ink.

Here, when the heating temperature of the print heater 20 is high, for example, the inkjet head in the head unit 12 is heated, so that problems such as nozzle clogging easily occur. In this case, the nozzle clogging is, for example, that the nozzles of the inkjet head are clogged due to the drying of the ink. Therefore, the heating temperature of the print heater 20 is preferably 70° C. or lower. Further, when using the instant dry type ink as in the present embodiment, it is possible to efficiently heat the ink by irradiating the ultraviolet light from the ultraviolet light source 104. Therefore, it is sufficient for the heating temperature of the print heater 20 to suppress the influence on the environmental temperature (ambient temperature) and to keep the temperature of the medium 50 constant, and it is more preferable not to overheat. .. More specifically, the print heater 20 heats a region facing the print heater 20, for example, at a temperature closer to room temperature (for example, about 50° C. or lower). The heating temperature of the medium 50 by the print heater 20 is preferably 40° C. or lower, more preferably 35° C. or lower. With this configuration, for example, it is possible to appropriately suppress the influence of environmental temperature and the like while suppressing problems such as nozzle clogging.

The preheater 22 is a heater that heats the medium 50 on the upstream side of the head unit 12 in the transport direction. By using the preheater 22, preheating can be performed before reaching the position of the head unit 12, and the initial temperature of the medium 50 can be appropriately adjusted. Further, in this case, the heating temperature of the medium 50 by the preheater 22 is sufficient if it is intended to suppress the influence on the environmental temperature, for example, and the temperature at which it is not overheated (for example, 50° C. or lower, preferably 40° C. or lower). C. or lower, more preferably 35.degree. C. or lower).

The after-heater 24 is a heater that heats the medium 50 on the downstream side of the head unit 12 in the transport direction. The after-heater 24 can be considered as, for example, a post-drying unit for promoting drying. By using the after-heater 24, for example, the ink can be dried more reliably until the printing is completed. The heating temperature of the medium 50 by the after-heater 24 may be about 30 to 50° C., for example. Further, the heating temperature of the after-heater 24 may be set to a certain high temperature within a range not higher than the heat resistant temperature of the medium 50 used.

The infrared heater 26 is a heater that heats the medium 50 by irradiating infrared rays. As the infrared heater 26, for example, an infrared light source that emits infrared rays including far infrared rays can be preferably used. Further, in the present embodiment, the infrared heater 26 heats the medium 50 together with the after-heater 24 on the downstream side of the head portion 12 in the transport direction. The infrared heater 26 can be considered as a heater for post-heating using infrared rays, for example. Further, in the present embodiment, the infrared heater 26 is disposed at a position facing the after-heater 24 with the medium 50 interposed therebetween as shown in FIG. To heat the medium 50. Further, as a result, the infrared heater 26 irradiates infrared rays toward the surface of the medium 50 on which the ink is attached.

In addition, in the present embodiment, the infrared heater 26 is an example of a post-heating unit that heats the ink after being irradiated with ultraviolet rays by the ultraviolet light source 104, and is used for fixing the heat fixing resin in the ink to the medium 50. The ink on the medium 50 is heated so that the temperature of the ink rises above the temperature. Further, as a result, the infrared heater 26 fixes the heat fixing resin together with the coloring material on the medium 50. With this configuration, for example, the ink can be fixed to the medium 50 in a state of having high robustness. Further, the infrared heater 26 can be considered as, for example, a unit that indirectly heats the ink via the medium 50 by heating the medium 50. The characteristics of the heat-fixing resin, the operation of fixing the heat-fixing resin on the medium 50, and the like will be described in more detail later together with the characteristics of the ink used in this embodiment.

Here, as described above, in the present embodiment, the after-heater 24 can also be considered as a means for heating the ink after being irradiated with ultraviolet rays by the ultraviolet light source 104. Therefore, the configuration in which the after-heater 24 and the infrared heater 26 are combined may be considered as an example of the post-heating means. Further, in this case, regarding the configuration that performs heating at a relatively high temperature (for example, the infrared heater 26) as the main post-heating means, the configuration that performs heating at a relatively low temperature (for example, the after-heater 24) May be considered an auxiliary post-heating means. Further, as the print heater 20, the preheater 22, the afterheater 24, and the infrared heater 26, various known heating means may be used. Further, some or all of the print heater 20, the preheater 22, and the afterheater 24 may be omitted depending on the environment in which the printing apparatus 10 is used and the required print quality. Further, as the post-heating means, a heating means other than the infrared heater 26 may be used. In this case, for example, a warm air heater or a tungsten heater may be used as the post-heating means.

The control unit 30 is, for example, the CPU of the printing apparatus 10 and controls the operation of each unit of the printing apparatus 10. According to the present embodiment, for example, by ejecting the color ink onto the medium 50 by the inkjet heads 102c to 102k in the head unit 12, it is possible to appropriately draw an image or the like to be printed on the medium. Further, when the instant dry type ink is used as in the present embodiment, it is possible to suppress the occurrence of bleeding on the medium 50 of various materials and perform printing with high quality. Further, in this case, not only the ink of the instant drying type is used, but the ink having the heat fixing resin is used to fix the heat fixing resin to the medium 50 by heating, so that a state having high robustness is obtained. The ink can be fixed on the medium 50 with. Therefore, according to this embodiment, high-quality and highly durable printing can be appropriately performed.

For example, it is conceivable to use, as the medium 50, the same or similar material used as the object to be coated in the conventional powder coating method. As such a medium, for example, an uneven medium 50, a three-dimensional medium 50, or the like may be used.
In this embodiment, unlike the powder coating method, the powder does not scatter and it is not necessary to apply a high voltage to the medium. Therefore, compared with the case where coating is performed by the powder coating method, the cost and time required for environmental maintenance can be significantly reduced.
Further, in this case, since it is not necessary to apply a high voltage to the medium 50, it is possible to more appropriately perform printing on the medium 50 which is a material which is difficult to be coated by the conventional powder coating method.

Next, the features of the ink used in this embodiment will be described in more detail. FIG. 2 is a diagram showing an example of the configuration of the ink used in this embodiment, and schematically shows a part of the ink components. FIG. 2A shows an example of the ink composition. FIG. 2B shows another example of the ink composition. As described above, the ink used in this embodiment contains the coloring material, the heat fixing resin, and the solvent 202. In the case shown in FIG. 2A, the ink contains a solid and particulate pigment 204 as a coloring material. The pigment 204 can be considered as a powdery coloring material, for example. In addition, in this configuration, the ink contains, as the heat-fixing resin, the heat-fixing resin particles 206 that are resin particles. The heat-fixing resin particles 206 can be considered as, for example, resin particles that become powdery in a dry state. In this case, the pigment 204 and the heat-fixing resin particles 206 are contained in the ink in a state where they are dispersed in the solvent 202, as shown in the figure.

Further, the ink having this configuration can be considered as, for example, an ink obtained by further adding heat-fixing resin particles 206 to an instant drying type ink that uses the pigment 204 as a color material. In this case, as the particulate components such as the pigment 204 and the heat-fixing resin particles 206, for example, particles having a size that can secure aggregation stability during ink storage and ejection stability in an inkjet head are used. It is preferable. More specifically, the average particle size of each of these particles is preferably, for example, 30 nm or more and 1500 nm or less. When the average particle size is less than 30 nm, it is conceivable that agglomeration between particles tends to occur. Further, if the average particle size exceeds 1500 nm, precipitation tends to occur, which may cause a problem of storage stability. Further, in this case, ejection may be unstable in a high-resolution inkjet head having a nozzle diameter of 50 μm or less, for example.

Further, the pigment 204 and the heat-fixing resin particles 206 are not individually dispersed in the solvent 202, but the heat-fixing resin particles 206 include the pigment 204 therein as shown in FIG. 2B, for example. It may be integrated with the mixed resin particles and dispersed in the solvent 202. FIG. 2B shows another example of the ink composition. In this case, for example, the pigment 204 can be included in the heat-fixing resin particles 206 by using a method in which the resin as the material of the heat-fixing resin particles 206 and the pigment 204 are subjected to turbid polymerization, a kneading pulverization method, or the like. it can. Further, in this case, the heat-fixing resin particles 206 including the pigment 204 can be considered as, for example, colored heat-fixing resin particles including a coloring material and a heat-fixing resin. Further, the colored heat-fixing resin particles can be considered as particles of a resin containing the pigment 204 and the heat-fixing resin particles 206 as main components, for example. The heat-fixing resin particles 206 can be considered as particles of a resin containing a coloring material, for example. Further, in this case, it is preferable that the average particle diameter of the pigment 204 including the pigment 204 is 30 nm or more and 1500 nm or less. Further, as the pigment 204, a nano pigment or the like having an average particle diameter of less than 1 μm can be preferably used.

Further, in the ink of the present embodiment as shown in FIGS. 2A and 2B, for example, the solvent may be the same as or similar to that of the known instant drying type ink. In this case, for example, water can be preferably used as the main solvent which is the liquid component contained in the ink in the largest weight ratio. With this configuration, for example, the safety of the ink can be appropriately increased. Further, depending on the quality required for printing and the medium 50 used, it may be possible to use a solvent (organic solvent) as the solvent. More specifically, for example, depending on the material of the medium 50, a solvent may be used as a solvent for the purpose of improving the adhesiveness of the ink to the medium 50 and preventing curling or cockling of the medium 50 during printing. Conceivable.

In this case, a solvent (eco-solvent) having a boiling point of about 100° C. or higher (for example, 100° C. or higher and 250° C. or lower) is used from the viewpoint of improving the safety of the ink and preventing the nozzle clogging. preferable. As such a solvent, it is conceivable to use, for example, a solvent of isoparapines, a solvent of naphthenes, or a solvent of alkylbenzenes which is not subject to the organic law. Further, as the solvent, for example, it is possible to use a solvent composed of vegetable oils such as turpentine oil or linseed oil. Moreover, you may use the solvent which mixed the above-mentioned some solvent, for example.

Also, at least a part of the solvent of the ink is not limited to water, an eco solvent, etc., but a low boiling point solvent etc. may be used if necessary. In this case, for example, a solvent having a low boiling point may be added for the purpose of adjusting the drying speed of the ink. In addition, for example, when the heat-fixing resin particles 206 made of a special resin are used, it may be necessary to use a solvent corresponding to the organic law in combination with the heat-fixing resin particles 206. .. In such a case, it is possible to use a solvent having a low boiling point, if necessary.

Further, in the ink of the present embodiment, when the solvent 202 evaporates on the medium 50, the pigment 204 and the heat-fixing resin particles 206 remain as a powder on the medium. Then, in this state, heating is performed by the infrared heater 26 (see FIG. 1) used as the post-heating means, so that the heat-fixing resin forming the heat-fixing resin particles 206 becomes a film and is fixed on the medium 50. In this case, the ink preferably contains the heat-fixing resin forming the heat-fixing resin particles 206 in a weight ratio of 20% by weight or more. According to this structure, the ink can be appropriately formed into a film by heating with the infrared heater 26. In this case, it is conceivable that the infrared heater 26 heats the medium 50, for example, so that the temperature of the medium becomes 80° C. or higher (preferably 90° C. or higher, more preferably 100° C. or higher). Further, in this case, the infrared heater 26 can be considered as an example of a high temperature fixing unit and a high temperature post-drying unit.

As the heat-fixing resin forming the heat-fixing resin particles 206, for example, a thermoplastic resin or a thermosetting resin can be preferably used. When a thermoplastic resin is used as the heat-fixing resin, for example, a resin having a glass transition point of 100° C. or higher can be preferably used. Further, in this case, by heating the medium 50 by the infrared heater 26, for example, the ink is heated to a temperature at which the heat fixing resin is melted or higher. Further, as a result, for example, the ink is heated so that the heat fixing resin cooled after being heated by the infrared heater 26 is fixed to the medium 50. When a thermosetting resin is used as the heat fixing resin, for example, a resin having a polymerization initiation temperature of 90° C. or higher can be preferably used. Further, in this case, by heating the medium 50 by the infrared heater 26, for example, the ink is heated to a temperature equal to or higher than the temperature at which the heat fixing resin is cured. With such a configuration, for example, the ink can be appropriately fixed to the medium.

Further, more specifically, when a thermoplastic resin is used as the heat-fixing resin, for example, vinyl chloride, polyethylene, nylon resin, or powder of a mixture thereof can be preferably used. When a thermosetting resin is used as the heat-fixing resin, for example, an epoxy-based resin, an epoxy-polyester-based (hybrid resin), a polyester-based resin, a fluororesin-based resin, or a powder mixture thereof is preferably used. You can

Further, as described above, the ink used in the present embodiment may further contain the same or similar component as the known ink (for example, known instant drying type ink). More specifically, as a component other than the above, the ink may further include, for example, an ultraviolet absorber (UV absorber). The ultraviolet absorber is, for example, a substance that absorbs ultraviolet rays and converts them into heat. In this case, for example, it is conceivable to add the ultraviolet absorber in an amount of about 0.2 to 5% by weight with respect to the total weight of the ink. As the ultraviolet absorber, for example, a known ultraviolet absorber can be preferably used. Further, if another component in the ink sufficiently absorbs ultraviolet rays to generate heat without separately adding an ultraviolet absorber, it can be considered that the component also serves as an ultraviolet absorber.

Also, the ink may further contain other components. In this case, for example, it is possible to further add a binder resin as a component of the ink. The binder resin is, for example, a resin that can be formed into a film only by evaporating the solvent and without performing additional heating or the like. By using such a binder resin, it is possible to appropriately prevent the components of the ink remaining on the medium from scattering after the solvent in the ink is evaporated and before the heating by the infrared heater 26 is performed. be able to. Further, in this case, the binder resin can be considered as a resin or the like for temporarily fixing (hypothetical attachment) the powdery component in the ink onto the medium. When the binder resin is used, for example, it is preferable to add the binder resin in a weight ratio of about 10% by weight or less (for example, about 0.1 to 10% by weight) with respect to the entire ink. Further, the binder resin is not an essential component of the ink, but can be considered as a component or the like added when it is desired to increase the strength of temporary fixing after the ink is dried. Therefore, the binder resin may not be added depending on the required print quality. In comparison with the binder resin, the heat-fixing resin used in the present embodiment does not form a film only by evaporating the solvent, but forms a film by heating to a predetermined temperature or higher. It can be considered as a resin or the like.

Further, as a component of the ink, for example, in order to promote the flattening of the ink layer (ink image) at the time of fixing, a low temperature melting resin (for example, paraffin or wax) having a melting point of 100° C. or less is added. Things can be considered. In addition to the above, as an ink component, for example, an additive for stabilizing dispersion or adjusting viscosity may be added. Further, the components of the ink of the present embodiment are not limited to the printing ink, and it is conceivable to further add a known additive or the like used in paints and the like.

Next, the printing operation performed by the printing apparatus 10 (see FIG. 1) of this embodiment will be described in more detail. FIG. 3 shows the printing operation of the printing apparatus 10. 3A to 3D show examples of the state of the medium 50 at various timings in the printing operation.

FIG. 3A is a diagram illustrating an operation of ejecting ink onto the medium 50. Further, for convenience of illustration, in FIG. 3A, a plurality of inkjet heads (inkjet heads 102c to 102k) in the head unit 12 is represented by one inkjet head 102. Further, among the plurality of ultraviolet light sources 104, only the ultraviolet light source 104 which is on the rear side of the inkjet head 102 in the moving direction of the head portion 12 in the main scanning operation is illustrated. In the operation shown in the drawing, the head unit 12 ejects ink from the inkjet head 102 while moving in the direction shown by the arrow in the drawing. Further, the temperature of the ink is raised by irradiating the image (ink image) drawn by the ink landed on the medium 50 with ultraviolet rays from the ultraviolet light source 104. This also prevents the solvent of the ink from rapidly evaporating and prevents the ink from bleeding. Further, in the present embodiment, as described above, the print heater 20 provided in the platen 14 heats the medium 50 at a low temperature of 50° C. or lower, thereby suppressing the influence of the environmental temperature. There is.

FIG. 3B shows an example of the state of the medium 50 immediately after the solvent in the ink is evaporated by the irradiation of the ultraviolet light from the ultraviolet light source 104 (after the evaporation of the solvent in the instant drying method). In this case, of the ink components, the components that do not evaporate remain on the medium 50. More specifically, in the present embodiment, the pigment and the dried heat-fixing resin particles become aggregated powder and remain on the medium 50. Therefore, this state can be considered, for example, as a state in which an image composed of agglomerated powder is formed on the medium 50. Further, this state can be considered as, for example, a state in which an unfixed image (unfixed ink image) is formed on the medium 50. Further, such an unfixed image can be considered to be, for example, an image in which the ink is powdered and roughened.

FIG. 3C is a diagram illustrating an operation of heating ink by the infrared heater 26 to fix the ink on the medium 50. As described above, in the present embodiment, the ink on the medium 50 is heated to a high temperature (for example, 100° C. or higher) by the infrared heater 26 to form a film of the heat fixing resin, and the ink Is fixed to the medium 50. Further, in the present embodiment, as described above, the afterheater 24 provided in the platen 14 is further used to heat the ink at a high temperature.

More specifically, when a thermoplastic resin is used as the heat-fixing resin, for example, by heating the portion of the medium 50 that has been conveyed to the position of the infrared heater 26 by the infrared heater 26, the heat-fixing resin is Heating is performed to raise the temperature above the melting temperature. In addition, this softens the heat-fixing resin and forms a film of the heat-fixing resin in a molten state containing the pigment and the like. With this configuration, for example, the ink layer can be appropriately flattened. In this case, by cooling the medium 50 thereafter, the ink layer can be firmly adhered (adhered) to the medium 50. Such an operation can be considered as, for example, an operation of heating and melting and fixing the ink on the medium 50 at a high temperature. When a thermosetting resin is used as the thermosetting resin, the thermosetting resin is cured by heating the portion of the medium 50 that has been conveyed to the position of the infrared heater 26 by the infrared heater 26 ( Heating and heating is performed to a temperature not lower than the (curing by heating). Further, by this, the heat-fixing resin is formed into a film while containing the pigment and the like. Even with such a configuration, the ink layer can be firmly attached to the medium 50.

Here, the operation of heating the ink by the infrared heater 26 and fixing the ink on the medium 50 can be considered as, for example, an operation of sinter fixing. Further, as described above, the heating temperature by the infrared heater 26 is set to, for example, 100° C. or higher (for example, 100° C. or higher and 250° C. or lower) according to the characteristics of the heat fixing resin used. It is possible to do it. In addition, the heating temperature of the infrared heater 26 is usually preferably set to a high temperature of 130° C. or higher (for example, 130° C. or higher and 200° C. or lower). When the heating temperature of the infrared heater 26 is too low, for example, the degree of flattening may be low, and the printed image may have a roughened impression. In addition, the adhesive strength of the ink layer may be insufficient. If the heating temperature of the infrared heater 26 is too high, for example, the ink or the medium 50 may be burnt. Further, it is considered that the viscosity of the ink is excessively lowered due to the melting of the heat fixing resin, which causes a problem of bleeding.

Further, in FIG. 1, for convenience of illustration, a configuration in which heating by the infrared heater 26 is performed only in a relatively short section in the transport path of the medium 50 is illustrated. However, when considering fixing the ink on the medium 50 with higher quality, it is preferable to sufficiently lengthen the heating time of the infrared heater 26. Therefore, for example, when heating is performed by the infrared heater 26 in a part of the conveyance path of the medium 50, it is preferable to dispose the infrared heater 26 so that the time for heating by the infrared heater 26 can be sufficiently secured.

Further, more specifically, the time for heating the medium 50 by the infrared heater 26 is preferably 10 minutes or more (for example, about 10 to 20 minutes). In this case, the time for heating the medium 50 by the infrared heater 26 is, for example, the time for heating each position (one position) of the medium 50 by the infrared heater 26. According to this structure, for example, it is possible to properly secure the time for flattening the heat fixing resin by melting or the like. Further, in this case, for example, by sufficiently fixing the ink, it is possible to appropriately perform defoaming or the like for removing the air contained in the ink layer.

After heating by the infrared heater 26, the area of the medium 50 heated by the infrared heater 26 is cooled to complete the fixing of the ink. In this case, for example, cooling to room temperature by natural cooling can be considered. Further, if necessary, the medium 50 may be cooled by using a cooling unit such as a blower fan. Further, in order to fix the ink on the medium 50 with higher quality, for example, cooling the medium 50 so as not to quench it may be considered. In this case, for example, a configuration in which a section for heating at a temperature lower than that of the infrared heater 26 is provided, a configuration in which a heat annealing process in which a low temperature state (section) and a high temperature state (section) are repeated a plurality of times, and the like are performed. Can be used. According to this structure, for example, the influence of thermal strain can be reduced and the adhesive force of the ink layer can be increased more appropriately.

FIG. 3D shows an example of the state of the medium 50 in which the fixing of the ink layer is completed. As shown in the figure, according to the present embodiment, for example, by using the ink containing the heat fixing resin, the ink on the medium 50 is heated by the infrared heater 26, and thus the adhesiveness to the medium 50 is extremely high. Ink can be firmly adhered in a high state. Further, this makes it possible to appropriately perform high-quality printing with high smoothness and high robustness. Further, more specifically, as described above, in the present embodiment, the medium 50 is, for example, the same as or similar to the object to be coated which has been conventionally coated by the powder coating method. Can be used. Then, in this case, for example, it is possible to appropriately perform printing having high fastness similar to the conventional powder coating method. The same as or similar to the object to be coated, which has been conventionally coated by the powder coating method, is, for example, household electric appliances, road materials, and many other industrial products. Further, as such a medium 50, it is conceivable to use, for example, a material that is required to have high durability, such as a material that constitutes a road sign, a guide rail, or an outdoor signboard.

Next, a supplementary explanation about each configuration explained above will be given. First, in this embodiment, an ink containing a component which becomes powdery when dried is used. Therefore, the ink used in the present embodiment can be considered to be, for example, liquefied powder coating ink. An inkjet head that ejects such an ink can be considered as, for example, a unit that applies liquefied powder coating ink. In addition, as described above, the ink used in this embodiment is an instant dry type ink that generates heat when irradiated with ultraviolet rays. Therefore, the ink of the present embodiment can be considered to be, for example, UV instant dry powder dispersion ink. Further, when considering the inclusion of heat-fixing resin particles and the use of UVLED as an ultraviolet light source, the ink of this embodiment may be, for example, a UV flash drying type heat-fixing resin particle ink or a UV-LED flash drying. It can be considered as a heat fixing resin particle ink or the like.

Further, the specific configuration of the ink used in this embodiment is not limited to the configuration described above, and various modifications are possible. FIG. 4 is a diagram for explaining the example of the ink used in this embodiment in more detail. As described above, in the present embodiment, an ink containing a coloring material, heat fixing resin particles, a solvent and the like is used. Further, the configuration of such an ink is not limited to the ink having the configuration described above, and various changes can be made. FIGS. 4A to 4G are views showing various examples of the ink used in the present embodiment. When the ink containing the colored heat-fixing resin particles 206 is used, the heat-fixing resin particles 206 are shown. The various examples of the structure of are shown.

FIG. 4A is a diagram showing the configuration of the ink shown in FIG. 2B. As shown in the figure, in this case, the heat-fixing resin particles 206 are colored by the inclusion of the pigment 204 in the heat-fixing resin particles 206. Further, this configuration can be considered to be, for example, a configuration in which the pigment 204 used as a color material is dispersed in the heat fixing resin particles 206 in advance. With this configuration, for example, the aggregation of the pigment 204 in the ink can be appropriately prevented. Further, in this case, for example, by using an ink having a small size such as a nano-pigment, it is possible to appropriately realize an ink configuration capable of high-definition printing.

Further, in the modified example of the ink composition, the surface of the heat-fixing resin particles 206 is further covered with another polymer substance (for example, a polymer resin), so that the heat-fixing resin particles 206 are microencapsulated. It is also conceivable to form particles. In this case, for example, as shown in FIG. 4B, it is possible to cover the outside of the heat-fixing resin particles 206 having the configuration shown in FIG. With this configuration, for example, the properties of the surface of the particles contained in the ink can be appropriately adjusted (modified) as necessary. Further, as a result, for example, when the heat fixing resin particles 206 are melted by heating by the infrared heater 26, it is possible to improve the familiarity between the particles and thereby to have an effect of assisting the agglomeration between the particles. become.

Further, the color material of the ink is not limited to the pigment 204, and other types of color materials may be used. In this case, for example, it is possible to use an inorganic or organic coloring material that dissolves or disperses in any of the components in the ink. Further, more specifically, it is possible to use a dye as the color material other than the pigment 204. Further, in this case, for example, as shown in FIG. 4C, both the pigment 204 and the dye may be used as the coloring material.

In the case shown in FIG. 4C, the heat fixing resin particles 206 are colored (dyed) with a dye. In addition, the heat-fixing resin particles 206 are encapsulated by being covered with a polymer substance 208 around them. Further, the polymer substance 208 covers the periphery of the heat fixing resin particles 206 in a state where the pigment 204 is included therein. With respect to this configuration, for example, a configuration in which the heat-fixing resin particles 206 forming the central portion (core) of the particles contained in the ink are colored with a dye, and the pigment 204 such as a nanopigment is attached (adhered) around the dye I can think. With this configuration, for example, darker color ink can be appropriately created. Further, by using a dye and a pigment, for example, an ink having both the color rendering properties of the dye and the weather resistance of the pigment can be prepared.

Also, it is possible to use only dyes as the color material of the ink. In this case, for example, as shown in FIG. 4D, it may be considered to use heat fixing resin particles 206 colored with a dye. With this configuration, for example, it is possible to perform printing with high color rendering properties by utilizing the high transparency realized by the dye. Further, for example, as shown in FIG. 4E, a polymer substance 208 may be added to the heat-fixing resin particles 206 having the configuration shown in FIG. Also in this case, for example, the property of the surface of the particles contained in the ink can be modified, and the effect of assisting the agglomeration between the particles when the heat fixing resin particles 206 are melted can be obtained.

Regarding the configuration using both the pigment and the dye as the coloring material, for example, the configuration shown in FIG. 4(f) may be used. This structure is, for example, a structure in which the polymer substance 208 for microencapsulation is further colored with a dye in addition to the structure shown in FIG. Further, for example, as shown in FIG. 4G, it is possible to color the heat-fixing resin particles 206 containing the pigment 204 with a dye. With such a configuration, for example, darker color ink can be appropriately created. Also in these cases, by using the dye and the pigment, for example, an ink having both the color rendering properties of the dye and the weather resistance of the pigment can be prepared.

As described above, the printing device 10 according to this embodiment has the following configuration.
(1) The printing device 10 prints on the medium 50.
The printing device 10 includes a head unit 12 (ejection head) that ejects ink onto the medium 50,
An ultraviolet light source 104 (energy ray irradiation unit) for irradiating the medium 50 with ultraviolet rays (energy rays);
An infrared heater 26 (post-heating means) that heats the ink after being irradiated with ultraviolet rays by the ultraviolet light source 104.
The ink generates heat by absorbing the ultraviolet light emitted by the ultraviolet light source 104.
The ink includes a pigment 204 (coloring material), heat fixing resin particles 206 (heat fixing resin) that is a resin that is fixed to the medium 50 by being heated by the infrared heater 26, and a solvent 202.
The ultraviolet light source 104 irradiates the ink attached to the medium 50 with ultraviolet light to evaporate at least a part of the solvent 202 in the ink.
The infrared heater 26 heats the ink to fix the heat fixing resin particles 206 to the medium 50 together with the pigment 204.

By using this configuration and using the instant dry type ink that generates heat when irradiated with ultraviolet rays, it is possible to perform printing appropriately on various media 50. For example, it is possible to form an ink layer having the same high adhesiveness and high fastness as the coating film formed by the powder coating described above.

Also, unlike the powder coating method, the powder does not scatter, and it is not necessary to apply a high voltage to the medium 50. Therefore, compared with the case of coating by the powder coating method, the cost and time required for environmental maintenance can be significantly reduced, and the working environment can be improved.

Further, by irradiating the ink on the medium 50 with ultraviolet rays to evaporate at least a part of the solvent 202, the viscosity of the ink can be appropriately increased before heating with the infrared heater 26. This makes it possible to appropriately suppress ink bleeding even when a plurality of colors of ink are used. Therefore, a plurality of heads 12 that eject inks of different colors are used to perform color printing (for example, full-color printing). ) Is also possible.
Further, by using the ink containing the heat fixing resin particles 206 and heating the ink on the medium 50 by the infrared heater 26, the ink can be more firmly attached to the medium 50.

Here, in the case of the powder coating method, in principle, the object to be coated is limited to a conductive metal or the like that can effectively apply an electric field.
On the other hand, with the above configuration, it is not necessary to apply an electric field, and thus various media 50 can be used. For example, it is possible to use various media 50 that can withstand the temperature at the time of heating for fixing the heat fixing resin particles 206.
Examples of the medium 50 include inorganic materials such as insulating glass and ceramics, and organic materials such as heat resistant plastics. When the printing result is compared with the printing result of a general inkjet printer, a strong film-like ink layer can be formed on various media 50.
Therefore, high-quality printing can be appropriately performed on various media.

Note that it is possible to apply a voltage between the inkjet head and the medium 50, if necessary. In this case, by charging the ink ejected from the inkjet head so that it can be attracted to the medium 50, the space between the inkjet head and the medium 50 is widened as in the case of coating by the powder coating method. Then, printing can be performed.

As described above, the printing device 10 according to this embodiment has the following configuration.
(2) The infrared heater 26 heats the ink to form the heat-fixing resin particles 206 on the medium 50 and fix the heat-fixing resin particles 206 to the medium 50 together with the pigment 204.

With this configuration, the ink can be fixed to the medium 50 more appropriately.

As described above, the printing device 10 according to this embodiment has the following configuration.
(3) The heat fixing resin particles 206 are a thermoplastic resin.
The infrared heater 26 heats the ink until the heat-fixing resin particles 206 are dissolved, so that the heat-fixing resin particles 206 that have been cooled after being heated by the infrared heater 26 are fixed to the medium 50. Heat the ink.

With this configuration, the ink can be appropriately fixed to the medium 50.

As described above, the printing device 10 according to this embodiment has the following configuration.
(4) The heat-fixing resin particles 206 are thermosetting resins.
The infrared heater 26 heats the ink until the heat-fixing resin particles 206 are cured, so that the heat-fixing resin particles 206 that have been cooled after being heated by the infrared heater 26 are fixed to the medium 50. Heat the ink.

With this configuration, the ink can be appropriately fixed to the medium 50.

As described above, the printing device 10 according to this embodiment has the following configuration.
(5) The infrared heater 26 heats the ink by heating the medium 50. The infrared heater 26 heats the medium 50 so that the temperature of the medium 50 is at least 80°C.

With this configuration, heating for fixing the heat-fixing resin particles 206 on the medium 50 can be performed reliably and appropriately.

As described above, the printing device 10 according to this embodiment has the following configuration.
(6) The ultraviolet light source 104 heats the ink so that the temperature of the ink on the medium 50 does not exceed the boiling point of the solvent 202. The infrared heater 26 heats the ink so that the temperature of the ink on the medium 50 exceeds the boiling point of the solvent.

With this configuration, it is possible to appropriately prevent bumping of ink or the like when heating with the ultraviolet light source 104. In addition, the ink can be appropriately and sufficiently heated when being heated by the infrared heater 26.

As described above, the invention of the printing method can be specified.
That is,
(7) A printing method of printing on the medium 50.
A head unit 12 (ejection head) that ejects ink onto the medium 50;
An ultraviolet light source 104 (energy ray irradiation unit) for irradiating the medium 50 with ultraviolet rays (energy rays);
An infrared heater 26 (post-heating means) that heats the ink after being irradiated with ultraviolet rays by the ultraviolet light source 104 is used.
The ink is an ink that generates heat by absorbing the ultraviolet light emitted from the ultraviolet light source 104.
The ink includes a pigment 204 (coloring material), heat fixing resin particles 206 (heat fixing resin) that is a resin that is fixed to the medium 50 by being heated by the infrared heater 26,
And a solvent 202.
The ultraviolet light source 104 irradiates the ink attached to the medium 50 with ultraviolet light to evaporate at least a part of the solvent 202 in the ink.
The infrared heater 26 heats the ink to fix the heat fixing resin particles 206 to the medium 50 together with the pigment 204.

With this configuration, it is possible to appropriately perform high-quality printing on various media.

Further, in order to further enhance the fastness of the ink after fixing, a substance for enhancing the fastness of the ink may be further added to the ink. FIG. 5 is a diagram showing a further modified example of the ink composition, showing an example of the ink composition when zinc oxide particles are further added as a component of the ink.
5A and 5B show an example of the configuration of the ink containing the zinc oxide particles 210. 5 may have the same or similar characteristics as those in FIGS. 1 to 4 except for the points described below.

As shown in FIG. 5, the ink contains a solvent 202, a pigment 204, heat-fixing resin particles 206, and zinc oxide particles 210. In the ink of the example shown in FIG. 5A, the pigment 204 and the heat-fixing resin particles 206 are included in the heat-fixing resin particles 206. In addition, in the case of the example shown in FIG. 5B, in addition to the pigment 204 and the zinc oxide particles 210 contained in the heat-fixing resin particles 206, the ink also contains the pigment 204 outside the heat-fixing resin particles 206. And zinc oxide particles 210. Even when such an ink is used, the ink containing the heat-fixing resin particles 206 can be used to appropriately fix the ink to the medium 50.

Also, zinc oxide is a highly stable and hard substance. Therefore, by adding the zinc oxide particles 210 to the ink, for example, the robustness of the ink after fixing can be further improved. Further, in this case, since zinc oxide is a substance that is almost colorless (for example, transparent or white), it is unlikely that the color of the ink changes greatly when added. Therefore, it becomes possible to add a sufficient amount of zinc oxide particles 210, etc., if necessary.

Also, zinc oxide is a substance that generates heat by absorbing ultraviolet rays. Therefore, in the ink to which the zinc oxide particles 210 are added, the zinc oxide particles 210 can also be used as an ultraviolet absorber. In this case, the ultraviolet light source 104 (see FIG. 1) heats the ink by causing the zinc oxide particles 210 in the ink to generate heat by irradiation with ultraviolet light. According to this structure, for example, the fastness of the ink after fixing can be increased by utilizing the substance for heating the ink. When using the zinc oxide particles 210 as an ultraviolet absorber, it is preferable to use, for example, a UVLED having a central wavelength of light emission of about 350 to 380 nm in the ultraviolet light source 104. The central wavelength of the light emitted by the UVLED is more preferably about 360 to 370 nm. As the zinc oxide particles 210, it is preferable to use particles having an average particle size of about 1 μm or less (for example, 0.01 to 1 μm). The average particle size of the zinc oxide particles 210 is preferably 0.2 μm or less.

Here, in the ink of this configuration, the zinc oxide particles 210 are an example of particles of a solid inclusion and a metal oxide contained in the ink. In this case, the solid inclusion is, for example, a solid substance that is fixed to the medium together with the thermosetting resin. Further, the solid-containing material can be considered to be, for example, a solid substance dispersed in a solvent. Further, the solid content can be considered as, for example, a filler added to the ink.

As such a solid inclusion, a substance other than the zinc oxide particles 210, for example, calcium carbonate, titanium oxide, polysiloxane, silicon oxide, aluminum oxide or the like may be used. Further, as the solid inclusion, only one kind of substance may be used alone, or a plurality of substances may be used in combination. Also in this case, as in the case of using the zinc oxide particles 210, for example, it is conceivable to use a substance or the like that enhances the hardness of the ink fixed to the medium 50 as compared with the ink not containing the solid content. With this configuration, for example, the robustness of the ink after fixing can be appropriately increased. Further, more specifically, as such a solid-containing material, for example, particles of a metal oxide other than zinc oxide may be used. Also in this case, it is possible to use, for example, a metal oxide that generates heat by absorbing ultraviolet rays as the solid-containing material. Further, as the solid-containing material added to the ink, a substance that does not function as an ultraviolet absorber may be used. In this case, for example, it is conceivable to add an ultraviolet absorber to the ink separately from the solid inclusion.

When the UV absorber is added to the ink separately from the solid-containing material, it is considered to use, for example, a known organic compound-based UV absorber. Examples of such UV absorbers include UV absorbers used in radical polymerization chemical reactions (radical polymerization UV absorbers) and UV absorbers used in cationic polymerization chemical reactions (cations). It is conceivable to use a polymerization type ultraviolet absorber). More specifically, examples of radical polymerization type ultraviolet absorbers include benzyl dimethyl ketal (type) 1, α-hydroxyacetophenone (type) 2 to 6, and α-aminoacetophenone (type) 7 to 9 and the like. Acetophenone-based UV absorbers, acylphosphine oxide-based photocuring initiators such as monoacylphosphine oxide (MAPO) and bisacylphosphine oxide (MAPO), O-acyloximes such as O-acyloximes 16 and 17 It is conceivable to use a photo-curing initiator, an oxime ester-based photo-curing initiator such as IRGACURE01-02, a titanocene-based photo-curing initiator such as titanocene, or a bimolecular reactive photo-curing initiator such as benzophenone, thioxanthone or ketocoumarin. .. Examples of the cationic polymerization type ultraviolet absorber include onium salt-based substances such as onium salts 27 to 29, iodonium salt 24, nonionic diaryliodonium salt, triaryliodonium salt, diphenyliodonium salt, and the like. It is conceivable to use a nonionic photocationic polymerization initiator such as iodonium salt or sulfonium salt, imide sulfonate, oxime sulfonate, and the like. In addition to these, for example, it is possible to use a known inorganic ultraviolet absorber or the like. Also, a plurality of types of substances may be added to the ink as the ultraviolet absorber.
As a result, the robustness of the ink after fixing on the medium 50 can be further improved.

As described above, the further modified example of the configuration of the ink used in the printing apparatus 10 has the following configuration.
(8) The ink is a solid substance that is fixed to the medium 50 together with the heat-fixing resin particles 206, and further contains metal oxide particles (solid content).

With this configuration, the robustness of the ink after fixing can be appropriately increased.

As described above, the further modified example of the configuration of the ink used in the printing apparatus 10 has the following configuration.
(9) The metal oxide particles contained in the ink are zinc oxide particles 210.
The zinc oxide particles 210 generate heat by absorbing the ultraviolet light emitted from the ultraviolet light source 104, and increase the hardness of the ink fixed on the medium 50 to be higher than the hardness of the ink not containing the zinc oxide particles 210.

With this configuration, it is possible to appropriately increase the robustness of the ink after fixing by using a substance that causes the ink to generate heat.

[First Modification]
FIG. 6 shows a printer 10A according to a first modification. 6 has the same or similar features as the configuration of the printing apparatus 10 according to the present embodiment, except for the points described below.

The printing apparatus 10 according to the present embodiment has been described by way of an example in which the printing apparatus 10 is integrally configured including the post-heating means for fixing the ink on the medium 50, but the present invention is not limited to this. For example, the printing device 10A may include a plurality of devices.

As shown in FIG. 6, the printing device 10A includes a printing unit 42, a heating unit 44, and a winding unit 46. The printing unit 42 is a main body portion (printer portion) of the printing apparatus 10A and performs an operation of ejecting ink onto the medium 50 and an operation of drying ink on the medium 50. The printing unit 42 has a configuration in which the infrared heater 26, which is a post-heating unit, is provided separately from the printing apparatus 10 in FIG.

The heating unit 44 is a portion having the infrared heater 26, and heats the ink on the medium 50 after the processing in the printing unit 42 is completed by the infrared heater 26, so that the heat fixing resin in the ink is removed. After being formed into a film, the heat fixing resin is fixed to the medium 50 together with the coloring material. The heating unit 44 can be considered as a portion corresponding to the infrared heater 26 in the configuration of the printing device 10. Further, the heating unit 44 is configured as a device having a housing different from that of the printing unit 42. When a thermoplastic resin is used as the heat-fixing resin, the printing unit 42 can be considered as, for example, a melting heating unit that melts the heat-fixing resin in the ink. Further, in the printing apparatus 10A, as the medium 50, a roll-shaped medium 50 that is wound after being heated by the heating unit 44 is used. The winding unit 46 is a unit that winds the medium 50 after the processing in the heating unit 44 is completed.

As described above, the printing apparatus 10A according to the first modified example has the following configuration.
(10) The printing device 10A prints on the medium 50.
The printing apparatus 10A includes a head unit 12 that ejects ink onto the medium 50,
An ultraviolet irradiation unit 104 that irradiates the medium 50 with ultraviolet rays.
The ink generates heat by absorbing the ultraviolet rays emitted by the ultraviolet ray irradiation unit 104.
The ink includes a pigment 204, thermofixable resin particles 206 that are fixed to the medium 50 by being heated by the infrared heater 26 (post-heating means) of the heating unit 44, and the solvent 202.
The ultraviolet irradiation unit 104 irradiates the ink attached to the medium 50 with ultraviolet rays to evaporate at least a part of the solvent 202 in the ink.
The infrared heater 26 of the heating unit 44 heats the ink after being irradiated with ultraviolet rays by the ultraviolet ray irradiation unit 104. The infrared heater 26 of the heating unit 44 heats the ink to fix the thermosetting resin particles 206 together with the pigment 204 on the medium 50.

With this configuration, even when the heating temperature of the heating unit 44, which is a housing different from the printing unit 42, is increased, it is possible to more appropriately prevent the influence of high-temperature heating from affecting each configuration of the printing unit 42. be able to. Further, this can more appropriately prevent, for example, nozzle clogging of the inkjet head in the head unit 12 of the printing unit 42 and frequent occurrence of ejection defects.

FIG. 7 shows an example of the configuration of the constant temperature bath 32 used as a heating means.

In the printing apparatus 10A according to the first modified example, the case where the heating unit 44 configured as a device of a housing different from the printing unit 42 has the infrared heater 26 has been described as an example, but the present invention is not limited to this. ..
For example, as shown in FIG. 7, instead of the infrared heater 26, a heating unit 44A having a constant temperature bath 32 may be used. In the constant temperature bath 32, heating is performed under the condition that the temperature of the medium 50 is 130° C. or higher.
As the medium 50, for example, a rigid type medium 50 (rigid medium) is used instead of the roll-shaped medium 50 (see FIG. 7).

In this case, as the configuration of the printing unit 42, for example, a flat bed type configuration or the like can be preferably used. The flatbed type configuration is, for example, a configuration in which an image is drawn on the medium 50 by moving the head unit side in the main scanning direction and the sub-scanning direction while the position of the medium 50 is fixed. Also in this case, for example, in the same or similar manner as described above with reference to FIGS. 3A and 3B, the ink is ejected to the medium 50, the operation of drying the ink by the instantaneous drying method, or the like is performed. It can be performed. Further, in this case, after the ink is dried by the instant drying method, the medium 50 is moved to the inside of the constant temperature bath 32 in the heating unit 44 and heated at high temperature.

By doing so as well, the ink can be firmly adhered to the medium 50 in a film-formed and flattened state.
Further, it is possible to more appropriately perform the post-heating on the medium 50 which is difficult to be conveyed by the roller or the like. Further, it becomes possible to perform heating at a higher temperature while suppressing the influence on the surroundings.

[Second Modification]
In the printing apparatus 10 according to this embodiment, the case where the infrared heater 26 is used as the post-heating unit has been described as an example, but the present invention is not limited to this. For example, instead of the infrared heater 26, a printing device may be used that uses a unit that heats the ink by irradiating the ink with ultraviolet rays (energy rays).

It is conceivable that the irradiation of ultraviolet rays by the post-heating means is performed under conditions different from the irradiation of ultraviolet rays performed immediately after landing on the medium 50.
In the case of using ultraviolet rays (for example, ultraviolet rays having a central wavelength of light emission of about 360 to 390 nm), the ultraviolet light source 104 (see FIG. 1) in the head portion 12 is transferred to the medium 50 in order to prevent ink bleeding. Immediately after landing the ink, the ink is irradiated with ultraviolet rays. In this case, if the ink vigorously bumps, the heat-fixing resin or the like, which has been powdered by drying, may be greatly scattered around. Therefore, for the conditions for irradiating ultraviolet rays (required irradiation intensity), the irradiation intensity and irradiation time of ultraviolet rays are selected so that the temperature of the solvent does not greatly exceed the boiling point, depending on the boiling point of the main solvent contained in the ink.
More specifically, the energy per unit area irradiated from the ultraviolet light source 104 to the medium 50 may be, for example, 0.01 J/cm 2 or more and 5 J/cm 2 or less. Further, the irradiation intensity of ultraviolet rays per unit area is set to 1 to 15 W/cm 2, and the irradiation time for irradiating each position of the medium 50 with ultraviolet rays is usually preferably less than 1 second. The irradiation time for irradiating each position on the medium 50 with ultraviolet rays is more preferably about 0.05 to 0.5 seconds.

On the other hand, in the post-heating for melting or curing the heat-fixing resin, it is preferable to heat the ink so that the high temperature continues for a certain time or longer. Then, in this case, for example, it is preferable to maintain the temperature of the ink at a high temperature while preventing the temperature of the medium 50 or the ultraviolet light source from rising excessively. Therefore, it is conceivable that the ultraviolet light source used as the post-heating means (the ultraviolet light source for post-heating) irradiates the ink on the medium 50 with pulsed ultraviolet light for at least 1 second, for example. In this case, it is preferable to irradiate the ink with ultraviolet rays having a duty ratio of 50% or less. According to this structure, the ink can be appropriately heated while preventing the temperature of the medium 50 and the like from rising excessively. Further, more specifically, in an ultraviolet light source for post-heating, for example, the irradiation intensity of ultraviolet light per unit area is 1 to 200 W/cm 2, and the irradiation time for irradiating each position of the medium 50 with ultraviolet light is It can be considered to be about 1 to 100 seconds. According to this structure, the ink can be appropriately fixed to the medium 50. Further, when the heat resistant temperature of the medium 50 is sufficiently high, the temperature of the medium 50 may be raised to a higher temperature (for example, 100° C. or higher) by irradiation with ultraviolet rays. Further, considering how to heat the ink by the ultraviolet light source 104 and how to heat the ink by the ultraviolet light source for post-heating in consideration of the boiling point of the solvent contained in the ink immediately after landing, for example, the ultraviolet light source The heating by 104 heats the ink so that the temperature of the ink on the medium does not exceed the boiling point of the solvent, and the heating by the ultraviolet light source for post-heating causes the temperature of the ink on the medium to reach this boiling point (the solvent that has already been volatilized and removed). It can be considered that the ink is heated to a temperature exceeding the boiling point of the ink. According to this structure, it is possible to appropriately prevent bumping of the ink or the like during heating with the ultraviolet light source 104. Further, the ink can be appropriately and sufficiently heated when being heated by the ultraviolet light source for post-heating.

As a result, only the temperature of the ink can be increased without significantly increasing the temperature of the medium 50. Specifically, the temperature of the ink is heated to 80°C or higher (preferably 90°C or higher, more preferably 100°C or higher) while suppressing the temperature of the medium 50 to about 60°C or lower (preferably 50°C or lower). You can
Accordingly, even when the heat resistant temperature of the medium 50 is low, the heat fixing resin can be appropriately and sufficiently heated.

As described above, the printing apparatus according to the second modified example has the following configuration.
(12) The ultraviolet light source as the post-heating means irradiates the ink with ultraviolet rays (energy rays) to heat the ink. The ultraviolet light source heats the ink by irradiating the ink with pulsed ultraviolet light for at least 1 second.

With this configuration, the ink can be appropriately heated while preventing the temperature of the medium 50 from rising excessively.

Further, in the printing apparatus 10, various changes can be made to each unit other than the post-heating means. For example, when ejecting ink containing a particulate component such as powder using an inkjet head (for example, a high-resolution head) used in recent inkjet printers, the ejectable particle size is usually 500 nm. It becomes the following. On the other hand, the size and the like of the heat-fixing resin and other components added to the ink in the above configuration are not particularly limited, and it is conceivable to use those having various particle diameters depending on the application and the like. Further, as a result, the particle diameter of the ink component may vary in the range of, for example, several nm to several μm. Therefore, the diameter (diameter) of the nozzle of the inkjet head may be 50 μm or more, if necessary. Further, in this case, it is preferable that the frequency of the signal for driving the inkjet head (driving frequency) and the like be appropriately changed according to the configuration of the inkjet head.

Also, the color of the ink used for printing is not limited to the color described above, and various changes are possible. More specifically, for example, in addition to each color of YMCK, it is possible to further use inks of each color of red color (R color), green color (G color), and blue color (B color). Further, a light color of each color, or a special color ink such as a pearl color, a metallic color, a white color, or a clear color may be further used. Further, in this case, it is conceivable to use an ink containing a color material of each color, a heat fixing resin, and a solvent as the ink of each color. Further, it is preferable to further add a solid-containing material such as zinc oxide, if necessary. Further, among the special colors, the clear color is a colorless and transparent color. When a solid content such as zinc oxide is added to a clear color ink, it can be considered that the solid content also serves as a color material for the clear ink.

Further, in the above description, as the configuration of the printing apparatus 10, the configuration of the serial method in which the head unit mainly performs the main scanning operation and the sub scanning operation has been described. In this case, the printing apparatus 10 ejects ink to each position of the medium by, for example, a multi-pass method in which the main scanning operation is performed a plurality of times for each position of the medium. However, the ink described above, the method of fixing the ink, and the like can be applied regardless of the printing conditions such as the print width. Therefore, as the configuration of the printing apparatus 10, it is also possible to use a line system (line printer) configuration in which ink is ejected by a one-pass system in which each position of the medium is passed through the inkjet head only once. .. Further, the present invention is not limited to these, and the type, arrangement, scanning method, etc. of the printing apparatus 10 are not limited.

The present invention can also be considered as a method for manufacturing a printed matter.

10, 10A... Printing device, 12... Head section, 14... Platen, 16... Guide rail, 18... Scan drive section, 20... Print heater, 22... Preheater, 24... After heater, 26... Infrared heater, 30... Control part, 32... Constant temperature bath, 42... Printing part, 44... Heating part, 46... Winding part, 50... Medium, 102... Inkjet head, 104... Ultraviolet light source, 202... Solvent, 204... Pigment, 206... Heat fixing resin particles, 208... Polymer substance, 210: Zinc oxide particles

Claims

A printing device for printing on a medium,
An ejection head for ejecting ink onto the medium,
An energy ray irradiation unit that irradiates the medium with energy rays,
A post-heating means for heating the ink after being irradiated with energy rays by the energy ray irradiating section,
The ink is an ink that generates heat by absorbing energy rays emitted by the energy ray irradiation unit,
Color material,
A heat-fixing resin that is a resin that is fixed to the medium by being heated by the post-heating means,
Including a solvent,
The energy beam irradiating unit irradiates the ink attached to the medium with an energy beam to evaporate at least a part of the solvent in the ink,
The printing apparatus, wherein the post-heating unit fixes the thermosetting resin together with the coloring material on the medium by heating the ink.
The post-heating unit heats the ink to form a film of the thermosetting resin on the medium, and fixes the thermosetting resin together with the coloring material on the medium. The printing apparatus according to Item 1.
The heat-fixing resin is a thermoplastic resin,
The post-heating means heats the ink until the heat-fixing resin is dissolved so that the heat-fixing resin cooled after heating by the post-heating means is fixed to the medium. The printing apparatus according to claim 1, wherein the ink is heated.
The thermosetting resin is a thermosetting resin,
The post-heating means heats the ink until the heat-fixing resin is cured so that the heat-fixing resin cooled after the heating by the post-heating means is fixed to the medium. The printing apparatus according to claim 1, wherein the ink is heated.
The post-heating means is a heater that heats the ink by heating the medium, and heats the medium so that the temperature of the medium becomes at least 80° C. The printing device according to claim 1.
The post-heating unit is a unit that heats the ink by irradiating the ink with energy rays, and heats the ink by irradiating the ink with pulsed energy rays for at least 1 second. The printing apparatus according to claim 1, wherein the printing apparatus is a printing apparatus.
The printing apparatus according to any one of claims 1 to 4, wherein the ink further includes a solid-containing material that is a solid substance that is fixed to the medium together with the thermosetting resin.
The printing apparatus according to claim 7, wherein the solid inclusions are metal oxide particles.
The solid-containing material generates heat by absorbing the energy rays irradiated by the energy-ray irradiating section, and enhances the hardness of the ink fixed on the medium as compared with the ink not containing the solid-containing material. Is a substance,
The printing apparatus according to claim 7, wherein the energy ray irradiating unit heats the ink by causing the solid content in the ink to generate heat by irradiating the energy ray.
The energy ray irradiator radiates ultraviolet rays as energy rays,
The printing apparatus according to any one of claims 7 to 9, wherein the solid inclusions are particles of zinc oxide.
The energy ray irradiation unit heats the ink so that the temperature of the ink on the medium does not exceed the boiling point of the solvent,
The printing apparatus according to claim 1, wherein the post-heating unit heats the ink so that the temperature of the ink on the medium exceeds the boiling point.
A printing device for printing on a medium,
An ejection head for ejecting ink onto the medium,
An energy ray irradiation unit that irradiates the medium with energy rays,
The ink is an ink that generates heat by absorbing energy rays emitted by the energy ray irradiation unit,
Color material,
A heat-fixing resin that is a resin that is fixed to the medium by being heated by a post-heating unit,
Including a solvent,
The energy beam irradiating unit irradiates the ink attached to the medium with an energy beam to evaporate at least a part of the solvent in the ink,
The post-heating means is a means for heating the ink after being irradiated with energy rays by the energy ray irradiating section, and by heating the ink, the heat fixing resin together with the coloring material on the medium. A printing device characterized by fixing.
A printing method for printing on a medium,
An ejection head for ejecting ink onto the medium,
An energy ray irradiation unit that irradiates the medium with energy rays,
Using a post-heating means for heating the ink after being irradiated with energy rays by the energy ray irradiation section,
The ink is an ink that generates heat by absorbing energy rays emitted by the energy ray irradiation unit,
Color material,
A heat-fixing resin that is a resin that is fixed to the medium by being heated by the post-heating means,
Including a solvent,
By irradiating the ink adhering to the medium with an energy ray by the energy ray irradiating section, at least a part of the solvent in the ink is evaporated,
A printing method comprising heating the ink by the post-heating means to fix the thermosetting resin together with the coloring material on the medium.