JPH0480039A - Thermal ink jet recorder - Google Patents

Abstract

PURPOSE:To obtain printing having neither scumming nor tailing and prevent a change on standing of drying or the like of ink from occurring by a method wherein hot melt ink having thermal plasticity is used and an application means which applies a bubble generating agent to a surface opposed to a thermal head of perforated film, is provided. CONSTITUTION:Ink 2 is thermal plastic hot melt ink and is dissolved by being heated with a heater 6. A perforated film 1 is driven with a roller 7. The ink 2 stuck to the perforated film 1 is controlled with a doctor blade and besides a bubble generating agent 9 is applied to a surface opposed to a thermal head 4 of the perforated film 1 with a coating roller 8. Further, recording paper 5 is so supported with a roller as to face the thermal head 4 keeping a micro gap, and recording is performed by the ink jetted from the perforated film 1. Further, for this bubble generating agent 9, a surface active agent dissolved in water may be also used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an inkjet image forming apparatus, and particularly to a thermal inkjet recording apparatus.

[Conventional technology]

Conventionally, the following recording method has been proposed as an inkjet recording method. The recording principle is that a perforated film filled with liquid ink with many fine through holes is run while in contact with a thermal head, and electricity is applied to the thermal head according to the recording pattern to cause a heating element to generate heat. The boiling point components vaporize to generate vapor bubbles, and the pressure of the bubbles causes ink to be ejected from the through holes. The ejected ink droplets reach and adhere to the opposing recording paper across a small gap to form a recording spot.

In this recording method, the number of through holes through which ink is ejected to form a recording spot corresponding to one heating element is not fixed, and if the density of the through holes is fine compared to the recording density, Since one recording spot is made up of ink droplets jetted from multiple through-holes, even if some of the through-holes become clogged and ink cannot be jetted, the recording result will not change. It has the characteristics of being able to perform highly reliable recording without causing major problems and without missing any dots.

[Problem that the invention seeks to solve]

In the conventional thermal ink sheet recording device described above, the ink filled in the through holes is a liquid ink with a low viscosity.
Since the ejected ink flies while diverging, increasing the distance from the opposing paper has the disadvantage that the diameter of the recording dots increases. Furthermore, if the distance between the sheet and the sheet facing the sheet is shortened, there is a drawback that stains and trailing dots occur when the sheet comes into contact with the perforated film.

[Means to solve the problem]

The thermal inkjet recording device of the present invention includes a perforated film having micropores and holding ink therein, a thermal head disposed opposite to the back surface of the perforated film, and a thermal head disposed opposite to the surface of the perforated film. A thermal ink sheet recording device comprising a recording paper and printing by jetting the ink onto the recording paper, wherein the ink is a thermoplastic hot melt ink, and the thermal head of the perforated film and It has application means for applying a bubble generating agent to the opposing surfaces. Further, the bubble generating agent may be a surfactant dissolved in water [Example] Next, the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing one embodiment of the present invention. In FIG. 1, ink 2 is a thermoplastic hot melt ink, and is heated and melted by a heater 6. The perforated film 1 is driven in the direction of the arrow by the rollerf.

The ink 2 adhering to the perforated film 1 is regulated by a doctor blade, and a bubble generating agent 9 is applied to the surface of the perforated film 1 facing the thermal head 4 by an application roller 8. The recording paper 5 is supported by a roller so as to face the thermal head 4 with a small gap therebetween, and recording is performed using ink jetted from the perforated film 1.

Note that the bubble generating agent 9 may be one in which a surfactant is dissolved in water.

FIGS. 2(a) to 2(d) are diagrams showing the process of printing by the thermal ink jet recording apparatus of the present invention. First, when a current is passed through the heating element 21 of the thermal head 4, heat is generated, and the water in the bubble generating agent reaches its boiling point, causing bubbles 22.
occurs (see Figure 2(a)). The generated air bubbles 22 develop by heating and gradually form the through holes 2 of the perforated film 1.
Push up the ink 2 attached to 5 (see Figure 2 (b))
Finally, the ink droplet 23 is ejected from the through hole 25 (see FIG. 2(c)). Then, a recording dot 24 corresponding to the energized heating zone 21 is formed on the recording paper 5 (second
(See figure (d)).

J Effects of the Invention: As explained above, the present invention can provide printing without background smudges or trailing by using the H-'z+~melt ink and the bubble generating agent. Furthermore, since the ink solidifies while the device is not printing, the problem of ink drying up over time, which has been a problem in the past, does not occur. Furthermore, because hot melt ink solidifies on the surface of the recording paper, it is less affected by the material of the recording paper than water-soluble ink.
It is also possible to print on special paper, which was difficult with conventional inkjet printers.

[Brief explanation of drawings]

Figure 1 is a sectional view showing one embodiment of the present invention, Figure 2 (a)
- Figure (d) is a diagram showing the process of printing by the thermal inkjet recording device of the present invention. DESCRIPTION OF SYMBOLS 1... Perforated film, 2... Ink, 3... Doctor blade, 4... Thermal head, 5... Recording paper, 6... Heater, 7... Roller, 8... - Application roller, 9...Bubble generating agent, 1...Heating element, 2...Bubble, 3...Ink droplet, 24...Recording dot, 5...Through hole.

Claims (1)

[Claims] 1. A perforated film having micropores and holding ink therein, a thermal head disposed opposite to the back surface of the perforated film, and a recording member facing the surface of the perforated film. a thermal inkjet recording device that prints by jetting the ink onto the recording paper, the ink being a thermoplastic hot melt ink, and a surface of the perforated film facing the thermal head; A thermal inkjet recording device characterized by comprising a coating means for coating a bubble generating agent on the surface of the thermal inkjet recording device. 2. The thermal ink jet recording apparatus according to claim 1, wherein the bubble generating agent is a surfactant dissolved in water.