The present invention relates to an inkjet printer which is configured to perform single-pass system image formation with aqueous ink on a web-shaped printing base material, and an inkjet printing method using the inkjet printer.
Hitherto, as a method of performing inkjet printing with aqueous ink on a printing base material through use of an inkjet printer, there has been proposed a method of performing printing while heating the printing base material being conveyed (Patent Document 1).
As a method of heating the printing base material being conveyed as described above, there has been employed a method of heating a back surface of the printing base material through use of a hot plate or the like.
However, even when the back surface of the printing base material is heated through use of the hot plate or the like, there arises the following problem in a case of performing printing while continuously conveying the printing base material. That is, when a printing speed reaches a speed of about 15 m/min, ink flow and color blurring caused by insufficient drying of ink and the like, color mixing during multicolor printing, and the like occur.
Further, as methods of performing printing while continuously conveying the printing base material, there are given a scan system and a single-pass system. Of those systems, the single-pass system is more suitable for high-speed printing because the single-pass system does not require scanning. A single-pass system inkjet recording method is disclosed, for example, in Patent Document 2. However, when the printing speed reaches the speed of about 15 m/min as described above, there arises a problem in that ink flow and color blurring caused by insufficient drying of ink and the like, color mixing during multicolor printing, and the like occur, with the result that there is difficulty in increasing the printing speed.
It is an object of the present invention to provide an inkjet printer which is capable of preventing ink flow and color blurring as well as color mixing during multicolor printing when image formation is performed with aqueous ink on a web-shaped printing base material, and to provide an inkjet printing method using the inkjet printer.
In order to solve the above-mentioned problems, an inkjet printer according to the present invention is an inkjet printer for aqueous ink which is configured to perform image formation by discharging aqueous ink to a web-shaped printing base material, and comprises: a conveyance mechanism configured to continuously convey the web-shaped printing base material; a single-pass system inkjet head configured to discharge, by a single-pass system, the aqueous ink to a surface of the web-shaped printing base material conveyed by the conveyance mechanism; and a surface pre-heating unit which is arranged on an upstream side of conveyance from the single-pass system inkjet head and is configured to heat at least the surface of the web-shaped printing base material, wherein image formation through use of the single-pass system inkjet head is performed on the web-shaped printing base material heated by the surface pre-heating unit.
Heating by the surface pre-heating unit is preferably performed through use of hot air blowing means for applying hot air to the surface of the web-shaped printing base material. As heating other than application of hot air to the surface of the web-shaped printing base material, the web-shaped printing base material can be heated by irradiation with a laser having a wavelength which is equal to an absorption wavelength of the web-shaped printing base material. Heating by irradiation with infrared light is also conceivable. However, when the web-shaped printing base material is a transparent film, infrared light passes through the web-shaped printing base material, with the result that the web-shaped printing base material is not heated. Therefore, in the case of heating by irradiation with infrared light, it is necessary that the web-shaped printing base material have black color or that the web-shaped printing base material be a base material having such a wavelength as to absorb infrared light. A combination of the above-mentioned heating through use of the hot air blowing means, heating by irradiation with a laser, and heating by irradiation with infrared light can also be used.
For example, hot air at a temperature of from 40° C. to 80° C. is preferably applied to the surface of the web-shaped printing base material through use of the hot air blowing means.
The hot air blowing means preferably comprises: a nozzle group main body having a plurality of slit-shaped hot air blowing nozzles arranged so as to form gaps therebetween, the plurality of slit-shaped hot air blowing nozzles each having a slit-shaped hot air outlet port extending in a width direction of the web-shaped printing base material; and a suction mechanism configured to suck an atmosphere of the gaps formed in the nozzle group main body.
The inkjet printer preferably further comprises a back surface heating unit configured to heat a back surface of the web-shaped printing base material. Heating by the back surface heating unit is preferably performed through use of hot air blowing means or a hot plate.
Further, heating means similar to the above-mentioned surface pre-heating unit may be arranged, as a surface post-heating unit, on a downstream side of conveyance of the web-shaped printing base material from the inkjet head.
The web-shaped printing base material is preferably a transparent film. As the web-like printing base material being the transparent film, a transparent film using PET (polyethylene terephthalate), PVC (polyvinyl chloride), PP (polypropylene), or the like may be suitably used.
An inkjet printing method according to the present invention comprises performing, through use of the said inkjet printer, single-pass system image formation through use of the single-pass system inkjet head with aqueous ink on the web-shaped printing base material heated by the surface pre-heating unit of the inkjet printer.
According to the present invention, there is provided a remarkable effect of being capable of providing an inkjet printer which is capable of preventing ink flow and color blurring, and color mixing during multicolor printing when image formation is performed with aqueous ink on a web-shaped printing base material, and an inkjet printing method using the inkjet printer.
Embodiments of the present invention are described below but those embodiments are described as examples and hence it is understood that various modifications may be made thereto without departing from the technical spirit of the present invention. In addition, the same members are denoted by the same reference symbols.
In
The surface pre-heating units 18b to 18e also act as surface post-heating units and also serve as the surface post-heating units 18b to 18e.
As the inkjet heads 16a to 16e, various known single-pass system inkjet discharge devices can be used.
As the conveyance mechanism 14, any known mechanism can also be used as long as the mechanism can convey the web-shaped printing base material 12. As illustrated in
Further, the original roller 22 around which the web-shaped printing base material 12 is wound is accommodated in a heating box 36, and is heated in advance (pre-heated) to a temperature of from 60° C. to 70° C. As a method of heating in the heating box 36, heating may be performed with hot air or by various known heaters. In the illustrated example, there is illustrated a configuration in which the inside of the heating box 36 is heated with hot air.
At least the surface of the web-shaped printing base material 12 heated in advance as described above is heated by the surface pre-heating unit 18a arranged on the upstream side of conveyance from the inkjet heads 16a to 16e. As the surface pre-heating unit 18a, an example is given of hot air blowing means. In the hot air blowing means, hot air at a temperature of from about 40° C. to about 80° C., for example, a temperature of 70° C. is applied to the surface of the web-shaped printing base material 12. A time period for applying hot air is from about 2 seconds to about 3 seconds in the case of a printing speed of 15 m/min, but is appropriately changed also depending on the temperature of the hot air.
An embodiment of the hot air blowing means to be used as the surface pre-heating units 18a to 18e is illustrated in
Further, in the example illustrated in
Further, in the embodiment illustrated in
Further, as the back surface heating unit 38, the hot air blowing means similar to the surface pre-heating unit 18a can also be used. Further, when the hot air blowing means is used as the back surface heating unit 38, it is suitable that, for example, hot air at a temperature of from 40° C. to 80° C. be applied to the back surface of the web-shaped printing base material 12.
In
Next, still another embodiment of an inkjet printer according to the present invention is illustrated in
In
With the inkjet printers 10A and 10B constructed as described above, when ink discharge by the inkjet heads 16a to 16e is performed with aqueous ink to the web-shaped printing base material 12 heated by the surface pre-heating unit 18a of the inkjet printers 10A and 10B, printing can be suitably performed with respect to a transparent PET film as the web-shaped printing base material without ink flow and color blurring, color mixing during multicolor printing, and the like even at a printing speed of 15 m/min. Further, as illustrated in the inkjet printers 10A and 10B, when the surface post-heating units and the back surface heating unit are combined, ink flow and ink blurring, color mixing during multicolor printing, and the like are further eliminated, and printing can be suitably performed.
10A, 10B: inkjet printer, 12: web-shaped printing base material, 14, 14a, 14b: conveyance mechanism, 16a to 16e: single-pass system inkjet head, 18a to 18e: surface pre-heating unit, 18b to 18f: surface post-heating unit, 20, 34: drive belt, 22: original roller, 24, 26, 28, 30: roller, 32: roll-up roller, 36: heating box, 38: back surface heating unit, 40a to 40e: laser irradiation device, 42, 52: hot air blowing means, 44: slit-shaped hot air outlet port, 46: slit-shaped hot air blowing nozzle, 48: gap, 50: nozzle group main body, H: hot air, I: aqueous ink, O: operator.
Number | Date | Country | Kind |
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2015-254090 | Dec 2015 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2016/086125 | 12/6/2016 | WO | 00 |