JPH07214763A - Ink jet printer and ink - Google Patents

Abstract

PURPOSE:To enable sharp printing by allowing an ink droplet to reach the surface of an object to be printed in proper viscosity without repelling the same therefrom by allowing the UV curable ink emitted from an ink head to reach the object to be printed while curing the same with UV rays from a UV lamp. CONSTITUTION:When a control signal is applied to a charge electrode 25 corresponding to printing content from a control unit, an ink droplet is chareged corresponding to the printing content and the charged ink droplet flies through the space between deflecting electrodes 26 to be changed in direction to draw a flight route shifted from an ink receiver 24 and flies out to the surface of an object to be printed. Since a UV lamp 27 is attached between the ink receiver 24 and the surface of the object to be printed, the ink droplet directed to the object to be printed without being received in the ink receiver 24 because the flight route thereof is bent by the electrodes 26 passes through a UV region. Proper viscosity is imparted to the ink droplet by adjusting the intensity of UV rays or the amt. of the ink droplet and, even when the ink droplet reaches a surface to be printed, it can be solidified without being formed into a spherical shape on the surface to be printed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet printer, and more particularly to an inkjet printer for printing on the surface of plastic or metal.

[0002]

2. Description of the Related Art Conventionally, there are ink jet printers using an oil-based ink and a water-based ink, each of which has the following characteristics.

The ink using the oil-based ink can be used for a wide variety of materials regardless of the type of printed matter because the ink has a quick-drying property, but on the other hand, it is difficult to increase the dot density and it is rough. This is printing and is not suitable for applications that require fine printing. Therefore, it is often used for industrial printing such as bar code and date printing in which fineness is not a problem.

On the other hand, the ink using the water-based ink has properties almost opposite to those of the oil-based ink. That is, since the dot density of the water-based ink can be higher than that of the oil-based ink, it is suitable for fine printing.
Since the ink has no quick-drying property, the material to be printed is limited to paper or the like. Therefore, it is often used mainly as a plotter for characters and pictures on paper.

[0005]

Recently, printers for articles for printing on plastic or metal have come to be used, but it is difficult to perform delicate printing on such materials. Met. That is, since it is difficult to increase the dot density of the oil-based ink, it is originally unsuitable for fine printing. Therefore, in order to print finely on plastic or metal, water-based ink is used, but if the ink used is water-based, the ink attached to the surface of these materials becomes spherical on the surface before drying and solidifying. It will be repelled. Therefore, it is impossible to print, or even if it is made, there are spots, and only aesthetically pleasing printing is obtained.

An object of the present invention is to solve the above problems in printing an article made of a material such as plastic or metal with an ink jet printer and to enable fine printing.

[0007]

An inkjet printer according to a first aspect of the present invention, which has been made to solve the above problems, ejects ink from an ink head onto an object to be printed. Equipped with an ultraviolet lamp that radiates ultraviolet rays to the ultraviolet curable ink until it reaches the printed material,
It is characterized in that the ultraviolet curable ink ejected from the ink head is cured and reaches the printing object.

The water-based ink for an ink jet printer according to the second aspect of the present invention, which has been made to solve the above problems, is characterized by containing an ultraviolet curing agent.

The operation of the ink jet printer and the ink will be described below.

[0010]

In the ink jet printer of the present invention, the ink containing the ultraviolet curing agent is used. The ink containing the ultraviolet curing agent (hereinafter referred to as UV curing ink) is ejected from the ink head of the inkjet printer toward the printing object. The ejected UV curable ink flies in the UV region generated by the UV lamp, and the UV curable ink reaches the substrate while being cured. Then, since the UV curable ink that has reached the surface of the material to be printed has been appropriately hardened, it is attached to the surface of the material to be printed without becoming spherical.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration explanatory view of an ink head portion of an ink jet printer showing an embodiment according to the present invention,
FIG. 2 is an overall view of the inkjet printer.

Inkjet printer 10 shown in FIG.
Is mainly composed of the ink head 20, head moving mechanisms 30 and 31 for moving the ink head 20 in two axial directions of the X direction and the Y direction orthogonal to each other, and a frame 40 containing these.

Then, as shown in FIG. 1, the ink head 2
At 0, a nozzle 21, an ink tank 22 for storing ink to be supplied to the nozzle 21, a pressure pump 23 for sending ink from the ink tank 22 to the nozzle 21, and a nozzle 2
There is provided an ink liquid circulation loop including an ink receiver 24 that collects the ink ejected during printing from the ink ejected from 1. The ink collected by the ink receiver 24 is returned to the ink tank 22 and sent to the nozzle 21 again.

Further, in order to deflect the ink droplets to the ink head 20, a charging electrode 25 that periodically applies a charge according to the printing content to the ink droplets ejected from the nozzle 21 in response to a command from a control device (not shown). , And the ink droplets charged by the charging electrode 25 change the flight path between the deflection electrodes 26 as indicated by the alternate long and short dash line in the figure.
It comes off and goes toward the substrate under it.

The ink head 20 has an ink receiver 2
An ultraviolet lamp is attached between the surface 4 and the surface (A side) of the printed material so that the ink droplets ejected from the ink receiver 24 are irradiated with ultraviolet rays.

Next, the operation of the ink jet printer having this structure will be described. In this inkjet printer, a water-based ink (UV curable ink S) containing an ultraviolet curing agent is used. As the ultraviolet curing agent, for example, a mixture of ink and acrylic resin liquid is used.
The UV curable ink S is put in the ink tank 22 and ejected from the nozzle 21 via the pressure pump 23. The ink droplets of the UV curable ink S ejected from the nozzle 21 fly into the space and become particles.

When no control signal is given to the charging electrode 25 from the control device (not shown), the ejected ink droplets go straight on and are collected in the ink receiver 24 in front of them and returned to the ink tank 22.

When a control device (not shown) gives a control signal to the charging electrode 25 according to the print content, the ink droplets are given a charge according to the print content. Then, the charged ink droplets change their direction by flying in the space of the deflection electrode 26, and draw a flight path that deviates from the ink receiver 24. Ink droplets will fly out toward you.

An ultraviolet lamp 27 for irradiating the space with ultraviolet rays is attached to the back side of the ink receiver 24 of the ink head 20, that is, the space between the ink receiver 24 and the surface of the printing material. Therefore, since the flight path is bent by the deflection electrode 26, the ink receiver 2
Ink droplets which are not collected in 4 and are directed to the printing material pass through this ultraviolet region. Since the ink droplet contains an ultraviolet curing agent, it gradually cures when it reaches the printing surface by receiving ultraviolet rays. By adjusting the intensity of this ultraviolet ray and the amount of one ink drop and adjusting them to appropriate conditions, it is possible to impart an appropriate viscosity to the ink drop, and even if the ink drop reaches the surface to be printed, the ink The drops can solidify on the printing surface without spheronization. In the present embodiment, the ultraviolet lamp is mounted inside the ink head, but the present invention is not limited to this, and a case different from the ink head is provided in a range where ink can be irradiated during flight, and the ultraviolet lamp is installed in this case. May be. By doing so, the number of parts increases, but it is possible to prevent the ink head from increasing in size.

Further, as long as the material to be printed is not affected by the ultraviolet rays, the surface of the material to be printed may be simultaneously irradiated with the ultraviolet rays in addition to the ink droplets in flight. As a result, the curing can proceed even after the ink droplets have adhered to the surface, so that it is possible to easily adjust the intensity of ultraviolet rays and enable clearer and faster printing.

[0021]

As described above, in the ink jet printer according to the present invention, since the aqueous ink containing the ultraviolet curing agent according to the present invention is used for printing while irradiating the ink with ultraviolet rays, the ink can fly. It gradually hardens inside, and ink droplets can reach these surfaces with an appropriate viscosity, and clear printing is possible without being repelled on the surfaces.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an ink head that is a main part of an inkjet printer that is an embodiment of the present invention.

FIG. 2 is an overall configuration diagram of an inkjet printer that is an embodiment of the present invention.

[Explanation of symbols]

 10: Inkjet printer 20: Ink head 21: Nozzle 25: Charging electrode 26: Deflection electrode 27: Ultraviolet lamp

Claims (2)

[Claims] 1. An inkjet printer that prints ink ejected from an ink head onto a printing object, comprising an ultraviolet lamp that irradiates ultraviolet rays onto the ultraviolet curable ink that is ejected from the ink head and reaches the printing object. An inkjet printer characterized in that an ultraviolet curable ink ejected from an ink head is cured while reaching an object to be printed. 2. A water-based ink for an inkjet printer, which contains an ultraviolet curing agent.