JP2020082460A - Inkjet printer and method for manufacturing printed matter - Google Patents

Abstract

To preferably print on a medium using water-containing ink to solve such the problem that a medium may be deteriorated such that the medium is deformed, discolored or burnt by heat because not only ink but also the medium are heated when being heated by a halogen lamp.SOLUTION: An inkjet printer 100 includes: a print head 40 for applying water-containing ink for inkjet to an application object; and an infrared-ray radiation unit 60 for radiating an infrared ray having a wave length within a range of 2.5 to 3.2 μm to the water-containing ink applied to the application object.SELECTED DRAWING: Figure 2

Description

The present invention relates to an inkjet printer and a method for manufacturing a printed matter.

In recent years, in inkjet printing, there is an increasing demand for inks containing a large amount of water (hereinafter referred to as water-containing inks) such as water-based inks in order to reduce environmental load. However, in inkjet printing using a water-containing ink, the water-containing ink wets and spreads on the media and is absorbed by the media, so that bleeding tends to occur in the print, and the water-containing ink is absorbed by the media and remains on the media surface. There is a problem that the printed color becomes lighter than the desired color (thinning) because the amount of the water-containing ink visible to the eyes decreases.

In Patent Document 1, immediately after the aqueous ink containing an infrared absorber is applied to the medium, the aqueous ink is dried by the infrared rays emitted from the halogen lamp, whereby the aqueous ink is quickly fixed on the medium. This prevents bleeding and fading.

JP, 2013-189596, A

However, the heating by the halogen lamp heats not only the ink but also the medium, so that the medium may be deformed by heat, discolored, or scorched, so that deterioration of the medium may occur.

Further, if the heating temperature by the halogen lamp is lowered and the drying is performed for a long time, deterioration of the medium may be prevented, but the printing speed is reduced.

In view of the above, it is an object of the present invention to provide an inkjet printer and a method for manufacturing a printed matter, which can suitably print on a medium using a water-containing ink.

The inkjet printer according to the first aspect of the present invention is
A print head for applying a water-containing ink for inkjet to an application target;
An infrared irradiation unit for irradiating the water-containing ink applied to the application target with infrared rays having a wavelength in the range of 2.5 to 3.2 μm to evaporate at least a part of the water in the water-containing ink. ,
Equipped with.

According to the above configuration, it is possible to preferably print on the medium using the water-containing ink. In particular, the water-containing ink applied to the medium can be selectively and rapidly dried without causing deterioration of the medium. As a result, it is possible to suppress bleeding and fading of printing.

The infrared irradiation unit irradiates the water-containing ink with light in the wavelength range of 2.5 to 3.2 μm at an integrated energy of 0.3 J/cm ^{2 to 3} J/cm ² , and the water content in the water-containing ink. Is evaporated by 20 mass% or more,
Preferably.

According to the above configuration, it is possible to preferably print on the medium using the water-containing ink. In particular, the water-containing ink applied to the medium can be selectively and rapidly dried without causing deterioration of the medium. As a result, it is possible to suppress bleeding and fading of printing.

The infrared irradiation unit includes an LED or a laser diode,
Preferably.

According to the above configuration, it is possible to preferably print on the medium using the water-containing ink. In particular, the water-containing ink applied to the medium can be selectively and rapidly dried without causing deterioration of the medium. As a result, it is possible to suppress bleeding and fading of printing.

Further comprising a moving device that moves the infrared irradiation unit together with the print head with respect to the application target,
Preferably.

According to the above configuration, similarly to the above configuration, it is possible to preferably print on the medium using the water-containing ink. In particular, it is possible to further suppress bleeding and fading of printing.

A method of manufacturing a printed matter according to a second aspect of the present invention,
An applying step of applying a water-containing ink for inkjet to an application target by an inkjet method;
An infrared irradiation step of irradiating the water-containing ink applied to the application target with infrared rays having a wavelength in the range of 2.5 to 3.2 μm to evaporate at least a part of the water in the water-containing ink. ,
Equipped with.

According to the above configuration, it is possible to preferably print on the medium using the water-containing ink. In particular, the water-containing ink applied to the medium can be selectively and rapidly dried without causing deterioration of the medium. As a result, it is possible to suppress bleeding and fading of printing.

The application target is a medium,
In the infrared irradiation step, the moisture-containing ink on the medium is dried by the irradiation of the infrared rays until the moisture-containing ink is fixed on the medium.
Preferably.

According to the above configuration, similarly to the above configuration, it is possible to preferably print on the medium using the water-containing ink. In particular, since a drying process using an additional heater such as a print heater or an after-heater is unnecessary or can be completed in a short time, the printed matter can be efficiently manufactured.

The application target is a medium,
After the infrared irradiation step, further comprising a heating step of heating the water-containing ink on the medium with a heater until the water-containing ink is fixed on the medium.
Preferably.

According to the above configuration, similarly to the above configuration, it is possible to preferably print on the medium using the water-containing ink. In particular, it is possible to firmly fix the water-containing ink on the medium.

According to the present invention, it is possible to preferably print on a medium using a water-containing ink.

3 is a flowchart of a method for manufacturing a printed matter according to the first embodiment. FIG. 6 is a schematic configuration diagram of an inkjet printer according to a second embodiment. FIG. 6 is a schematic side view of an inkjet printer according to a second embodiment. The schematic top view of the inkjet printer which concerns on 2nd Embodiment. The schematic rear view of the inkjet printer which concerns on 2nd Embodiment. FIG. 9 is a schematic side view of an inkjet printer according to Modification 7. FIG. 8 is a schematic top view of an inkjet printer according to Modification 7. FIG. 10 is a schematic side view of an inkjet printer according to modification example 8.

(First embodiment)
A method for manufacturing a printed matter according to the first embodiment of the present invention will be described. In this manufacturing method, as shown in FIG. 1, a coating step S1 and a drying step S2 are mainly performed.

(Coating process S1)
In the applying step S1, the ink composition is applied to the medium by ejecting ink onto the medium with an inkjet printer.

(media)
The medium to be printed is arbitrary, and may be a medium such as cloth or porous medium that allows ink to permeate (hereinafter referred to as permeable medium), or a medium such as a plastic film that does not permeate ink (hereinafter referred to as non-permeable medium). Call it media). Examples of media materials include resin materials (polyethylene terephthalate, vinyl chloride, polyethylene, polypropylene, polycarbonate, acrylic, nylon, polystyrene, acrylonitrile-butadiene-styrene resin, etc.), paper, glass, metal materials (iron, aluminum, stainless steel). Etc.) and the like. The shape of the medium is not limited to a flat shape, and may be any three-dimensional shape as long as it can be printed by a three-dimensional inkjet printer.

It is preferable that the medium does not cause deterioration, for example, deformation, discoloration, charring, etc. of the medium due to the irradiation of the infrared ray itself in the drying step S2. For example, a medium in which the absorption of light having a wavelength of 2.5 to 3.2 μm is low enough not to cause deterioration is particularly preferable. For example, a medium having a transmittance of light having a wavelength of 2.5 to 3.2 μm of 30% or more, preferably 70% or more is particularly preferable. It should be noted that general printing materials such as polyethylene terephthalate and nylon usually do not show remarkable absorption in the wavelength range of 2.5 to 3.2 μm.

(Inkjet printer)
In the coating step S1, any inkjet printer can be used as long as it has a print head capable of ejecting ink described below and is compatible with the above-mentioned medium. In particular, it is preferable to use the inkjet printer 100 according to the second embodiment of the present invention, which will be described later, because the coating step S1 and the drying step S2 can be continuously and efficiently performed.

(Inkjet printing ink)
The ink used in the coating step S1 is any water-containing ink containing water, for example, 30% by mass or more, preferably 50% by mass or more, more preferably 70% by mass or more.

The water-containing ink includes, but is not limited to, (1) ink in which a coating film is formed on the medium by evaporation of most of the water in the ink applied on the medium, (2) medium Ink that suppresses wetting and spreading on the media due to evaporation of part of the water in the ink applied on top, (3) Penetration into the media by evaporation of part of the water in the ink applied on the media Examples of the ink include ink that suppresses

Such water-containing inks are not limited to these, but are water-based pigment inks, water-based dye inks, latex inks, gel jet inks, water-based UV inks, inks in which pigment-containing resin particles are dispersed. And so on.

The water-containing ink may further contain a water-soluble solvent as a solvent or a dispersion medium. Such a water-soluble solvent preferably has a boiling point of 60° C. to 100° C. so that it evaporates together with water upon irradiation with infrared rays. Examples of such water-soluble solvents include ethanol.

In the coating step S1, an image is printed on the medium using one or more colors of water-containing ink. For example, a set of four water-containing inks of cyan, magenta, yellow, and black may be used. However, in addition to or instead of these colors, a water-containing ink having a special color such as red, green, blue, white, pearl, metallic, ceramic, fluorescent, and phosphorescent may be used.

(Drying process S2)
In the drying step S2, the medium coated with the water-containing ink in the coating step S1 was irradiated with infrared rays having a wavelength in the range of 2.5 to 3.2 μm by an infrared irradiation device, so that the medium was coated on the medium. At least a part of the water content in the water-containing ink (for example, 20 mass% or more, preferably 50 mass% or more, and more preferably 70 mass% or more based on the mass of the water-containing ink before drying) is evaporated. This fixes the water-containing ink on the medium, or at least suppresses the bleeding of the water-containing ink on the permeable and non-permeable media and the permeation of the water-containing ink into the permeable medium.

(Light irradiation device)
In the drying step S2, any light irradiation device that can irradiate infrared rays having a wavelength in the range of 2.5 to 3.2 μm can be used. Examples of such a light irradiation device include, but are not limited to, an LED (Light Emitting Device) (for example, LED 29 (manufactured by Prolinks Co., Ltd.)) and a laser diode. Particularly, from the viewpoint of energy efficiency, it is preferable to use an LED as the light irradiation device.

When the light emitted from the light irradiation device has a component outside the wavelength range of 2.5 to 3.2 μm, it is preferable that such a component does not cause undesired heating of the medium or the printing device. For example, in the light emitted from the light irradiation device, the irradiation intensity of components other than the wavelength range of 2.5 to 3.2 μm may be less than 100 W/cm ² , 50 W/cm ² , or 10 W/cm ^2. preferable. In addition, the light emitted from the light irradiation device does not have a peak in the absorption wavelength region of the medium and/or a portion of the device that can be irradiated with the light and reflected light thereof (for example, a nozzle of a printing device), It is preferable that the component in the absorption wavelength range is not substantially contained.

In addition, the irradiation intensity of components other than the wavelength range of 2.5 to 3.2 μm in the light emitted from the light irradiation device is the wavelength range of 2.5 to 3.2 μm in the light emitted from the light irradiation device. It is preferable that the irradiation intensity of the component is less than that. Such light heats the water-containing ink more than the medium, that is, the water-containing ink selectively heats even if the medium absorbs light in all wavelength regions other than the wavelength region of 2.5 to 3.2 μm. It can be said that it will be done.

The light emitted from the light irradiation device may have a peak in the wavelength range of 2.5 to 3.2 μm. For example, the light emitted from the light irradiation device may exhibit a peak at one point in the wavelength range of 2.5 to 3.2 μm, or a peak plateau (peak) including a part or all of this wavelength range. Range). The light emitted from the light irradiation device preferably exhibits only a single peak. When the light emitted from the light irradiation device shows a plurality of peaks, wavelength components represented by peaks outside the wavelength range of 2.5 to 3.2 μm (for example, an irradiation intensity of 1/2 of the irradiation intensity of the peak wavelength is The irradiation intensity of the components within the two wavelengths shown) is preferably lower than the irradiation intensity of the wavelength component represented by the peak in the wavelength range of 2.5 to 3.2 μm.

(Infrared irradiation condition)
The infrared irradiation in the drying step S2 is performed immediately after the water-containing ink is applied to the medium in the applying step S1 so that the ink does not spread or penetrate too much. For example, the infrared irradiation in the drying step S2 is preferably started within 0.1 to 1.0 seconds after coating.

Further, the evaporation of at least a part of the water in the water-containing ink due to the infrared irradiation in the drying step S2 is completed in a short time so that the bleeding or the permeation of the ink does not proceed too much. For example, it is preferable to complete the evaporation of at least a part of the water in the water-containing ink by the infrared irradiation in the drying step S2 within 1 to 10 seconds.

The integrated energy of the light (particularly, the component in the wavelength range of 2.5 to 3.2 μm) with which the ink is irradiated in the drying step S2 is determined by the desired drying result (the water-containing ink is fixed on the medium, on the medium). It is optional as long as the bleeding of the water-containing ink is suppressed, the permeation of the water-containing ink into the permeable medium is suppressed, and the like, and it is 0.3 J/cm ^{2 to 5} J/cm ^2. Good. In particular, the component in the wavelength range of 2.5 to 3.2 μm of the light emitted to the ink in the drying step S2 is the accumulated energy sufficient to evaporate at least a part of the moisture in the moisture-containing ink by the component alone. It is preferable to have

The irradiation intensity of the light (particularly, the component in the wavelength range of 2.5 to 3.2 μm) with which the ink is irradiated in the drying step S2 is set according to the integrated energy and the desired drying time. For example, when the integrated energy is 0.3 J/cm ² and the drying time is 1 second, the irradiation intensity is preferably 0.3 W/cm ² . Further, for example, when the integrated energy is 3 J/cm ² and the drying time is 0.1 seconds, the irradiation intensity is preferably 30 W/cm ² .

(Other processes)
In the drying step S2, the bleeding of the water-containing ink on the permeable and non-penetrable media and the penetration of the water-containing ink into the permeable medium are suppressed, but the water-containing ink is not fixed on the medium to such an extent. In the case of evaporating the water in the above water-containing ink, after the drying step S2, in order to fix the water-containing ink on the medium, an arbitrary heater such as an electric heater, a warm air heater, an infrared heater, or the like is used on the medium. It is preferable to perform an additional drying step of further drying the water-containing ink. This makes it possible to firmly fix the water-containing ink on the medium.

Further, such an additional drying step may be performed when the moisture in the moisture-containing ink on the medium is evaporated to the extent that the moisture-containing ink is fixed to the medium in the drying step S2. Thereby, the fixing of the water-containing ink on the medium can be further strengthened.

Further, according to the type of the water-containing ink, the conventional process necessary for printing may be appropriately performed. For example, when a water-based UV ink is used as the water-containing ink, it is preferable to further include an ultraviolet irradiation step.

(Effects of the first embodiment)
Since the water-containing ink has high wettability and penetrability with water, it is easy to wet and spread on the medium, and it is easy to penetrate the penetrable medium such as cloth and porous medium. For this reason, conventionally, when printing is performed on a medium using a water-containing ink, there is a possibility that printing bleeding or fading may occur.

In addition, in order to eliminate printing bleeding and fading, it may be possible to dry the media printed with water-containing ink at high speed with a heater such as a xenon lamp. Since the medium is heated, the medium is deformed by heat, discolored, burnt, or the like, which causes deterioration of the medium.

Further, in order to eliminate the deterioration of the medium, an infrared absorbent is mixed with the water-containing ink, and the medium printed with the ink is irradiated with infrared rays by an infrared LED or a xenon flashlight, so that the ink is selectively and at high speed. Although it may be possible to dry it, in this case, since many infrared absorbers are colored, there is a risk that dullness of the ink may occur.

On the other hand, according to the manufacturing method of the first embodiment, the moisture in the water-containing ink can be selectively and quickly heated by infrared rays of a specific wavelength without blending a special infrared absorber, so that the deterioration of the medium Bleeding and fading of printing can be suppressed without causing dullness of ink or ink.

In addition, when an infrared absorbing agent is added to colored ink to make it easier to absorb infrared rays, the color of the colored ink becomes dull (blackens). Need not be added. Therefore, in the present manufacturing method, it is possible to print a more vivid image than before by using an ink having a vivid color tone, particularly, a special color ink having a vivid color tone.

(Second embodiment)
An inkjet printer 100 according to the second embodiment will be described with reference to FIGS. The inkjet printer 100 prints an image on the medium M made of a cloth roll using the above-described water-containing ink.

(Structure of Inkjet Printer 100)
As shown in FIG. 2, the inkjet printer 100 includes a transport mechanism 10, an ink tank 20, an ink supply mechanism 30, a print head 40, a drive mechanism 50, an infrared irradiation unit 60, a preheater 70, a print heater 71, an afterheater 72, And a control unit 80.

The transport mechanism 10 transports the medium M along the front-rear direction. As shown in FIG. 3, the transport mechanism 10 spreads the wrinkles of the medium M and the feeding roller that feeds the medium M from the roll so that the medium M is directly opposed to the nozzle surface of the print head 40. The holding platen (pre-platen 73, print platen 74, and after-platen 75) and a take-up roller that winds the medium M coated with the water-containing ink into a roll shape. The transport mechanism 10 may appropriately include a transport roller that changes the transport angle of the medium according to the transport path.

The ink tank 20 is an ink cartridge or an ink bottle that stores the water-containing ink of each color, and is attached to the inkjet printer 100.

The ink supply mechanism 30 is a mechanism that supplies the water-containing ink in the ink tank 20 to the corresponding print head 40. The ink supply mechanism 30 includes a sub-tank for storing the water-containing ink, a supply pipe for supplying the water-containing ink in the ink tank 20 to the sub-tank, and a circulation path for circulating the water-containing ink stored in the sub-tank via the print head 40. And a valve that controls the circulation of the water-containing ink in the circulation path, and a drive device that drives this valve.

The print head 40 discharges the water-containing ink supplied from the ink supply mechanism 30 by an on-demand type ink jet system and applies it to the medium M. In the figure, the water-containing ink ejected from the print head 40 is indicated by a broken line. The print head 40 stores the ink that circulates in the circulation path of the ink supply mechanism 30, a piezoelectric element or a heater that pushes out the water-containing ink stored in the storage chamber, and ejects the pushed water-containing ink. And a plurality of nozzles. Arrangement of the nozzles in the print head 40 is arbitrary, and for example, they may be arranged linearly in a line. One print head 40 may be provided for each color to be printed, or a plurality of colors of water-containing ink may be ejected from one print head 40.

The drive mechanism 50 moves the print head 40 in a direction (main scanning direction) orthogonal to the transport direction (sub scanning direction) of the medium M. As shown in FIGS. 3 to 4, the drive mechanism 50 includes a carriage 51 on which the print head 40 is mounted, a guide rail 52 that movably supports the carriage 51 in the main scanning direction, and one guide rail 52 at each end. The carriage 51 includes a towing line and a winding mechanism that winds the towing line, which are arranged as a set.

The infrared irradiation section 60 is for irradiating the water-containing ink applied to the medium M with infrared rays having a wavelength in the range of 2.5 to 3.2 μm, and includes a light irradiation device. In the figure, the outline of the light emitted from the infrared irradiation unit 60 is indicated by an arrow. The infrared irradiation units 60 are mounted on the carriage 51 one by one before and after the print head 40 (left and right in FIGS. 4 and 5) in the moving direction of the carriage (in the present embodiment, that is, the main scanning direction).

Examples of such a light irradiation device include, but are not limited to, an LED (Light Emitting Device) (for example, LED 29 (manufactured by Prolinks Co., Ltd.)), a laser diode, and the like.

The light irradiator may itself irradiate infrared rays having a peak emission wavelength in the wavelength range of 2.5 to 3.2 μm, or may have a wavelength of 2.5 to 3.2 μm due to the wavelength conversion mechanism. It may be one that emits light that can be converted into light having a peak in the region.

Examples of wavelength conversion mechanisms include, but are not limited to, wavelength conversion elements, wavelength conversion films, and the like.

When the light emitted from the light irradiating device has a component other than the wavelength range of 2.5 to 3.2 μm, this component is contained in the medium M or the member of the inkjet printer 100 (for example, the tip of the nozzle of the print head 40). The light irradiation device may be provided with a filter that suppresses or cuts at least a part of components other than the wavelength range of 2.5 to 3.2 μm so as not to cause undesired heating.

Examples of such filters include, but are not limited to, infrared bandpass filters.

Set the maximum print length setting value (in the present embodiment, that is, the length of the nozzle array of the print head 40 in the sub-scanning direction) that the print head 40 can print in the direction perpendicular to the moving direction of the infrared irradiation unit 60. When the print width W of the print head 40 is set, the infrared irradiation unit 60 defines the shape of the irradiated surface formed on the medium M by the light emitted from the light irradiation device as the print width W of the print head 40 and/or the ink. A light irradiation adjusting mechanism suitable for the light irradiation time required for drying may be provided.

Examples of such light irradiation adjustment mechanisms include, but are not limited to, beam expanders, cylindrical lenses, and the like.

The length A of the surface to be irradiated by the infrared irradiation unit 60 in the direction perpendicular to the moving direction of the infrared irradiation unit 60 (the sub-scanning direction in this embodiment) may be equal to or greater than the print width W of the print head 40, and energy efficiency can be improved. From the viewpoint, it is preferable that the print width is substantially the same as the print width W of the print head 40.

The length B of the surface to be irradiated by the infrared irradiation unit 60 in the moving direction of the infrared irradiation unit 60 (main scanning direction in this embodiment) is adjusted so that the light irradiation time required for drying the ink is secured. The length B of the surface to be irradiated is determined based on the moving speed v of the print head 40 and the light irradiation time t required for drying the ink. For example, when the print head 40 moves at a constant speed, that is, when v is constant, B may be tv or more.

Further, when the light irradiation device is small enough to be mounted on the carriage 51 and has high directivity, for example, the light irradiation device emits infrared rays having a peak emission wavelength in a wavelength range of 2.5 to 3.2 μm. When a plurality of infrared LEDs are used, the shape of the irradiated surface can be adjusted as described above only by the orientation and/or arrangement of the plurality of light irradiation devices without a light irradiation adjustment mechanism.

Further, the light (particularly, the ultraviolet ray reflection component) emitted from the infrared irradiator 60 and reflected by the medium M heats and dries the ink adhering to the nozzle surface of the print head 40 and the ink remaining in the nozzles. In order to prevent this, the infrared irradiation unit 60 irradiates the light at an irradiation angle at which the reflected light does not face the nozzle surface of the print head 40 by the light irradiation adjustment mechanism and/or the orientation and/or arrangement of the light irradiation device. Is preferably adjusted so that Therefore, it is particularly preferable to use a light source with high directivity, for example, an LED as the light irradiation device.

Furthermore, it is preferable that the infrared irradiation unit 60 irradiates the medium M with light so that the amount of light on the surface to be irradiated is uniform. Accordingly, the water-containing ink applied on the medium M can be dried uniformly. For example, when using a plurality of infrared LEDs that irradiate infrared rays of the same wavelength as the light irradiating device, each infrared LED emits the same amount of light, and there is no overlap between the surfaces to be illuminated by the individual infrared LEDs or all If the orientations of the infrared LEDs are adjusted so that the irradiated surfaces also overlap, the amount of light on the irradiated surface can be made uniform. Further, for example, when a laser diode is used as the light irradiation device, if the light irradiation adjusting mechanism such as a beam expander uniformly collects the light on the entire surface to be irradiated, the amount of light on the surface to be irradiated can be made uniform.

As will be described later, the infrared irradiation unit 60 uses at least a part (for example, 20% by mass or more, preferably 20% by mass, or more, of the water content of the water-containing ink applied on the medium M so that bleeding and lightening are hardly generated. , 50 mass% or more) in a short time (for example, in less than 1 second, preferably in less than 0.1 second). Therefore, it is preferable that the infrared irradiation unit 60, and thus the light irradiation device, can emit light with an irradiation intensity of 10 W/cm ² or more. In particular, the infrared irradiation unit 60, and by extension, the light irradiation device, has integrated energy (for example, 0.3 J/cm ^{2 to} 3.0 J/cm ² ) sufficient to evaporate at least a part of the water in the water-containing ink, It is preferable to irradiate light, particularly light in the wavelength range of 2.5 to 3.2 μm.

The pre-heater 70, the print heater 71, and the after-heater 72 are electric heaters for heating the medium M before, during, and after ink application, respectively, and include a pre-platen 73, a print platen 74, and It is attached to the after platen 75.

According to the preheater 70, for example, the temperature of the medium M can be set to a predetermined temperature in advance, so that the drying condition for drying by the infrared irradiation unit 60 can be made constant. The heating temperature of the preheater 70 is preferably close to the ambient temperature, for example, a temperature in the range of 25°C to 45°C, particularly preferably about 35°C.

Further, according to the print heater 71, in addition to the heating by the infrared irradiation unit 60, by further heating the water-containing ink applied to the medium M by the print heater 71, the bleeding of the water-containing ink can be further suppressed. it can. The heating temperature of the print heater 71 is preferably in the range of 30°C to 60°C, more preferably 35°C to 50°C.

Furthermore, by using the after-heater 72, for example, by completely drying the water-containing ink applied on the medium M, the fixing of the water-containing ink on the medium M can be made more reliable. The heating temperature of the print heater 71 is preferably in the range of 40°C to 150°C, and more preferably 60°C to 100°C.

As shown in FIG. 2, the control unit 80 includes a transport mechanism 10 (for example, a feeding roller and a take-up roller), an ink supply mechanism 30 (for example, the driving device described above), and a print head 40 (for example, a tactical piezoelectric element). Element or heater), the drive mechanism 50 (for example, the winding mechanism described above), the infrared irradiation unit 60, the pre-heater 70, the print heater 71, and the after-heater 72 to control the water-containing ink on the medium M. Is applied and dried to perform a printing process.

In order to perform such processing, the control unit 80 executes a storage device (hard disk, flash memory, etc.) that stores a program and various data and a program stored in the storage device, and uses the various data to perform the printing process. It is configured to include a processor (CPU (Central Processing Unit) or the like) to be executed, a main memory of the processor, and various interfaces. The control unit 80 may be, for example, a personal computer.

(Printing process)
The printing process starts when image data is supplied from an external host computer or the like. The image data includes data on whether or not the water-containing ink is ejected for each pixel.

The controller 80 first controls the transport mechanism 10 to move the medium M to the print start position.

Next, the control unit 80 controls the drive mechanism 50 to move the carriage 51, on which the print head 40 and the two infrared irradiation units 60 are mounted, relative to the medium M from right to left along the main scanning direction. Move (see FIG. 5).

During this movement, the control unit 80 controls the print head 40 at the timing when the nozzle of the print head 40 reaches the position of the pixel that ejects the water-containing ink (specified by the image data), and controls the print head 40 from the nozzle. The contained ink is ejected. In this way, the print layer P of the water-containing ink is formed on the medium M. Note that, in FIG. 5, the printing layer P is shown as a continuous film for the sake of simplification, but the printing layer P may be a continuous film made of a water-containing ink that is uniform throughout, or may be partially formed. It may be an assembly of a plurality of dots that are connected or are completely separated.

Further, during this movement, the control unit 80 controls the infrared irradiation unit 60 mounted on the right side of the carriage 51 to light the infrared irradiation unit 60 so that the printing layer P on the medium M is irradiated with infrared rays. In this way, at least part of the water in the water-containing ink in the print layer P and the permeation layer I is evaporated. From the viewpoint of energy efficiency, it is preferable that the control unit 80 controls the infrared irradiation unit 60 mounted on the left side of the carriage 51 to turn it off during the movement.

After that, the control unit 80 controls the transport mechanism 10 to feed the medium M in the sub-scanning direction by the printing width.

After that, the control unit 80 relatively moves the print head 40 from left to right along the main scanning direction. During this movement, the control unit 80 controls the print head 40 in the same manner as above to form the next print layer P. On the other hand, during this movement, the control unit 80 controls the infrared irradiation unit 60 mounted on the left side of the carriage 51 to turn on, instead of the infrared irradiation unit 60 mounted on the right side of the carriage 51. By irradiating the printing layer P with infrared rays, at least a part of the water in the water-containing ink in the printing layer P and the permeation layer I is evaporated. From the viewpoint of energy efficiency, it is preferable that the control unit 80 controls the infrared irradiation unit 60 mounted on the right side of the carriage 51 to turn off the infrared irradiation unit 60 during the movement.

By repeating the above, the entire image represented by the image data is printed on the medium M.

Note that the control unit 80 may control the pre-heater 70, the print heater 71, and the after-heater 72 at predetermined temperatures in the above printing process to accelerate the drying of the print layer P. Since the moisture in the print layer P is at least partially evaporated by the infrared irradiation unit 60, the heating temperature of these heaters can be set to a temperature lower than the conventional temperature. In general, the heat generation amount per unit power is better in a light irradiation device such as an LED or a laser diode than in other heaters such as an electric heater, and thus such temperature setting saves power consumption. ..

In particular, the control unit 80 controls the after-heater 72 to heat the printing layer P and the permeation layer I at a predetermined temperature so that the water-containing ink applied to the medium M can be firmly dried and fixed to the medium M. Good.

(Effects of the second embodiment)
The medium M made of cloth has a fine mesh structure. Therefore, as shown in FIG. 5, the water-containing ink in the printing layer P is localized on the medium M immediately after coating, but permeates into the mesh structure of the medium M due to a capillary phenomenon with the passage of time. I will do it. When the portion that has permeated into the mesh structure of the medium M is the permeation layer I, the amount of the water-containing ink in the printing layer P is reduced by the amount of the water-containing ink in the permeation layer I. May be thinner than the desired finish. Further, when the print layer P includes dots, there is a possibility that the boundary between the dots may be blurred as the water-containing ink in the dots permeates the medium M.

On the other hand, in the inkjet printer 100, the printed layer P is at least partially dried by the infrared irradiation unit 60 immediately after its formation, so that the permeation amount into the medium M is suppressed as compared with the case where it is not dried. Therefore, the degree of fading and bleeding is suppressed.

Further, when an infrared absorbing agent is added to the colored ink to make it easier to absorb infrared rays, the color of the colored ink becomes dull (blackened). No need to add absorbent. Therefore, in the inkjet printer 100, it is possible to print a more vivid image than before using an ink having a vivid color tone, particularly an ink having a special color having a vivid color tone.

(Modification 1)
In the second embodiment, a cloth roll is used as the medium M, but the shape and material of the medium M are arbitrary. For example, as the medium M, a non-permeable medium such as a vinyl chloride sheet may be used. Also in this case, the wettability of the water-containing ink is reduced by evaporating at least a part of the water content in the water-containing ink before the water-containing ink applied to the non-permeable medium wets and spreads on the medium and exhibits bleeding. By doing so, bleeding of the printed matter can be suppressed.

(Modification 2)
In the second embodiment and the above-described modified example, the inkjet printer 100 can be appropriately configured according to the medium M according to the related art.

For example, the transport mechanism 10 is optional as long as it can transport the medium M, and may be a belt conveyor. The table on which the medium M is placed and the table horizontally (for example, along the main scanning direction and the sub scanning direction). It may be provided with a drive mechanism that drives the motor to move. The belt conveyor type or table type conveying mechanism 10 is suitable for conveying articles such as sewn products such as shirts and products such as coasters as the medium M.

Further, the inkjet printer 100 may be configured as a three-dimensional printer. This configuration is suitable for printing as a medium M on a three-dimensional product such as a cup or a wine bottle.

(Modification 3)
In the second embodiment and the modifications described above, the configuration of the print head 40 itself is arbitrary.

For example, in the second embodiment, as the print head 40, the on-demand type ink jet system is adopted, but the continuous type ink jet system may be adopted.

Further, for example, in the second embodiment, one print head 40 is provided with a plurality of nozzles, but only one nozzle may be provided. Further, in the second embodiment, one print head 40 corresponds to one color, but one print head 40 may be provided with nozzles for a plurality of colors.

(Modification 4)
In the second embodiment and the modifications described above, the pre-heater 70, the print heater 71, and the after-heater 72 may be arbitrary heaters, and may be non-contact heaters such as warm air heaters. If it is a non-contact type heater, the pre-heater 70, the print heater 71, and the after-heater 72 may not be attached to the pre-platen 73, the print platen 74, and the after-platen 75.

Further, in the second embodiment and the above-described modified example, the pre-heater 70, the print heater 71, and the after-heater 72 may be omitted.

(Modification 5)
In the second embodiment and the above-described modified example, the print head 40 and the infrared irradiation unit 60 are provided on the same carriage 51, but the infrared irradiation unit 60 is provided after the ejection of the water-containing ink by the print head 40. The arrangement of the print head 40 and the infrared irradiation unit 60 is arbitrary as long as the infrared irradiation is performed on the water-containing ink applied to the medium M by the method.

For example, the infrared irradiation unit 60 may be configured to relatively move so as to follow the print head 40 with the relative movement of the print head 40. For example, as in Modification 6 described later, the print head 40 and the infrared irradiation unit 60 may be arranged in this order along the transport direction of the medium M (from front to back).

(Modification 6)
In the second embodiment and the modified example described above, the print processing is performed by the single-pass method, but the print processing may be performed by the multi-pass method.

In the second embodiment, when the printing process is performed by the multi-pass method, the light may be emitted from both of the two infrared irradiation units 60 during the printing process of the first and subsequent passes. In the case of the single-pass type, the printing layer P does not exist below the infrared irradiation unit 60 located in the front in the moving direction. Since the printing layer P exists, the infrared irradiation by the infrared irradiation unit 60 can further strengthen the drying of the printing layer P.

(Modification 7)
Although the print head 40 is configured as a serial printer type in the second embodiment and the above-described modified example, the print head 40 may be configured as a line printer type. Also in this case, the same effect as that of the second embodiment can be obtained.

An inkjet printer 200 is shown in FIGS. 6 and 7 as an example of such a line printer. The inkjet printer 200 has the same configuration as the inkjet printer 100 except for the print head 40, the driving mechanism 50, and the infrared irradiation unit 60, and thus the description of these configurations will be omitted.

In the inkjet printer 200, the print head 40 and the infrared irradiation unit 60 are arranged in this order along the sub-scanning direction and via a housing or the like so as to be at a constant distance from the print platen 74, which is the printing surface. It is fixedly arranged. Therefore, the drive mechanism 50 is omitted. Although only one infrared irradiation unit 60 is shown in FIGS. 6 and 7, a plurality of infrared irradiation units 60 may be provided as long as they are arranged behind the print head 40 along the sub-scanning direction. ..

The print head 40 and the infrared irradiation unit 60 extend along the main scanning direction, preferably with a length comparable to the length of the medium M in the main scanning direction, and more preferably with a length longer than that. ing.

In the print head 40, a plurality of nozzles are arranged along the main scanning direction. At this time, the print width W of the print head 40 becomes the length of the nozzle array of the print head 40 in the main scanning direction, as shown in FIG.

In the infrared irradiation unit 60, as shown in FIG. 7, the length A of the surface to be irradiated by the infrared irradiation unit 60 in the direction perpendicular to the relative movement direction of the infrared irradiation unit 60 is as follows: The length in the main search direction of the stippled portion in FIG. 7 and the length B of the surface to be irradiated by the infrared irradiation unit 60 in the relative movement direction of the infrared irradiation unit 60 are the same as the length of the surface to be irradiated in the sub-scanning direction. Become.

In the print process of the inkjet printer 200, when printing is started, the control unit 80 first controls the transport mechanism 10 to move the medium M to the print start position.

Next, the control unit 80 controls the transport mechanism 10 to feed the medium M from the front to the rear along the sub-scanning direction, that is, the print head 40 and the infrared irradiation unit 60 relative to the medium M. It is moved from the rear to the front along the scanning direction (see FIGS. 6 and 7).

During this movement, the control unit 80 controls the print head 40 at the timing when the nozzle of the print head 40 reaches the position of the pixel that ejects the water-containing ink (specified by the image data), and controls the print head 40 from the nozzle. The contained ink is ejected. In this way, the print layer P made of the water-containing ink is formed on the medium M.

Also, during this movement, the control unit 80 controls the infrared irradiation unit 60 to light it and irradiate the printing layer P on the medium M with infrared rays. In this way, at least part of the water in the water-containing ink in the print layer P and the permeation layer I is evaporated.

As a result, the entire image represented by the image data is printed on the medium M.

(Modification 8)
In the first embodiment, the second embodiment, and the modified example described above, the water-containing ink is applied to the medium. Instead of this, the water-containing ink is applied to any application target, and then the application target is applied. It is also possible to irradiate the water-containing ink applied to the substrate with infrared rays to vaporize at least a part of the water. Also in this case, the bleeding of the water-containing ink on the application target is suppressed.

In particular, in the second embodiment and the above-described modified example, the water-containing ink is directly applied to the medium M by the print head 40, but instead, the water-containing ink is first applied to the transfer belt by the print head 40, The moisture-containing ink on the transfer belt may be irradiated with infrared rays to evaporate at least part of the moisture, and then the moisture-containing ink may be transferred from the transfer belt to the medium M. Also in this case, the bleeding of the water-containing ink on the transfer belt is suppressed, and as a result, the bleeding of the water-containing ink transferred from the transfer belt to the medium is also suppressed. As described above, also in the eighth modification, the same effect as that of the second embodiment can be obtained.

An inkjet printer 300 is shown in FIG. 8 as an example of such a transfer printer. The inkjet printer 300 has the same configuration as the inkjet printer 200 except for the print head 40, the infrared irradiation unit 60, and the transfer unit 90, and thus the description of these configurations will be omitted.

The configurations of the print head 40 and the infrared irradiation unit 60 in the inkjet printer 300 are the same as the configurations of the print head 40 and the infrared irradiation unit 60 in the inkjet printer 200, except that the arrangement is reversed. .. In the inkjet printer 300, the infrared irradiation unit 60 and the print head 40 are provided with a housing or the like in this order along the sub-scanning direction and at a certain distance with respect to a part of a transfer belt 91 described later. It is fixedly arranged through.

The transfer unit 90 includes a transfer belt 91, a drive roller 92, and a pressing roller 93.

The transfer belt 91 is an infinite loop belt driven by a plurality of drive rollers 92 so as to be synchronized with the movement of the medium M by the transport mechanism 10. The transfer belt 91 is arranged such that a part thereof faces the print head 40 and the infrared irradiation unit 60, and another part thereof contacts the medium M.

The transfer belt 91 includes a support layer formed of a flexible belt (for example, a rubber belt), and a hydrophobic release layer attached to the surface of the support layer facing the print head 40 and the infrared irradiation unit 60.

The pressing roller 93 presses the transfer belt 91 against the medium M from the back surface at the contact point between the transfer belt 91 and the medium M, and transfers the water-containing ink applied on the transfer belt 91 to the medium M.

In the printing process of the inkjet printer 300, when printing is started, the control unit 80 first controls the transport mechanism 10 to move the medium M to the print start position.

Next, the controller 80 controls the transport mechanism 10 to feed the medium M from the front to the rear along the sub-scanning direction, and at the same time, controls the drive roller 92 to synchronize the transfer belt 91 with the movement of the medium M. And drive it. As a result, the print head 40 and the infrared irradiation unit 60 are moved relative to the medium M from the front to the rear along the sub-scanning direction (see FIG. 8).

During this movement, the control unit 80 controls the print head 40 at the timing when the nozzle of the print head 40 reaches the position of the pixel that ejects the water-containing ink (specified by the image data), and controls the print head 40 from the nozzle. The contained ink is ejected. In this way, the print layer P of the water-containing ink is formed on the transfer belt 91.

In addition, during this movement, the control unit 80 controls the infrared irradiation unit 60 to light it and irradiates the printing layer P on the transfer belt 91 with infrared rays. In this way, at least a part of the water in the water-containing ink in the print layer P is evaporated.

Further, the control unit 80 controls the pressing roller 93 to press the transfer belt 91 from the back surface toward the medium M when the print layer P on the transfer belt 91 reaches the medium M, and thus the transfer belt 91 is pressed. The print layer P is transferred to the medium M.

As a result, the entire image represented by the image data is printed on the medium M.

100, 200, 300 inkjet printer 10 transport mechanism 20 ink tank 30 ink supply mechanism 40 print head 50 drive mechanism 51 carriage 52 guide rail 60 infrared irradiation unit 70 preheater 71 print heater 72 afterheater 73 preplaten 74 print platen 75 afterplaten 80 Control unit 90 Transfer unit 91 Transfer belt 92 Drive roller 93 Pressing roller M Media P Printing layer I Penetration layer

Claims (7)

A print head for applying a water-containing ink for inkjet to an application target;
An infrared irradiation unit for irradiating the water-containing ink applied to the application target with infrared rays having a wavelength in the range of 2.5 to 3.2 μm to evaporate at least a part of the water in the water-containing ink. ,
With
Inkjet printer. The infrared irradiation unit irradiates the water-containing ink with light in the wavelength range of 2.5 to 3.2 μm at an integrated energy of 0.3 J/cm ^{2 to 3} J/cm ² , and the water content in the water-containing ink. The inkjet printer according to claim 1, wherein 20% by mass or more is evaporated. The inkjet printer according to claim 1, wherein the infrared irradiation unit includes an LED or a laser diode. Further comprising a moving device that moves the infrared irradiation unit together with the print head with respect to the application target,
The inkjet printer according to claim 1 or 2. An applying step of applying a water-containing ink for inkjet to an application target by an inkjet method;
An infrared irradiation step of irradiating the water-containing ink applied to the application target with infrared rays having a wavelength in the range of 2.5 to 3.2 μm to evaporate at least a part of the water in the water-containing ink. ,
A method of manufacturing a printed matter, comprising: The application target is a medium,
In the infrared irradiation step, the moisture-containing ink on the medium is dried by the irradiation of the infrared rays until the moisture-containing ink is fixed on the medium.
The method for manufacturing the printed matter according to claim 5. The application target is a medium,
After the infrared irradiation step, further comprising a heating step of heating the water-containing ink on the medium with a heater until the water-containing ink is fixed on the medium.
The method for manufacturing a printed matter according to claim 5 or 6.

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