JPH0387262A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To remove occurrence of bleeding of ink when plain paper is used by a method wherein ink to be hardened by water content is used and just after the ink is discharged from a head, its viscosity is raised by directing humid ink onto the ink. CONSTITUTION:Cyanoacrylate liquid ink 10, discharged from an ink jet head, which is low in viscosity and difficult to be clogged flies as an ink liquid drop 11 in a recording paper direction 12, and is stuck as an ink liquid drop 13 onto the recording paper 12 wound on a recording drum 17 to perform recording. Hardening reaction is accelerated by striking a humid air flow 14 onto the ink liquid drops 10, 11, 13 in flying, and the viscosity is raised. The humid air flow 14 is guided from an air blowing pump 16 by a pipe 15. An opening of the pipe 15 sends the ink liquid drops 10, 11, 13 while just after discharge of the ink to sticking onto the recording paper 12, and allows the humid air not to strike the ink in the ink jet head 9. Further, a nozzle opening part of the head 9 is thoroughly exposed to dry air in stop of operation, and hardening at the head nozzle part is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an on-demand inkjet recording device that prints characters, figures, etc. by ejecting ink droplets according to image signals to form dots on a recording medium. Regarding.

BACKGROUND OF THE INVENTION Conventionally, various methods have been devised regarding inkjet heads, which are a means of ink recording technology.
Normally, the viscosity is set to be low in order to easily eject liquid ink without clogging.

However, if the ink viscosity is set to a low value, the problem of ink smearing occurs on the recording paper. Therefore, for example, as disclosed in Japanese Patent Application Laid-Open No. 62-288048, solid ink is heated to raise its temperature, lowered in viscosity, and then ejected.
A method of cooling and solidifying on recording paper to prevent bleeding has been proposed.

An example of the structure of a conventional inkjet head using this solid ink is shown in FIG. In the figure, 1 is solid ink, which is heated and melted by a heater 3 to become liquefied ink 2. The liquefied ink 2 soaks into the infiltrated body 4 and is ejected from the tip 7 of the signal electrode 5 as a droplet due to the electrostatic field between the signal electrode 5 and the counter electrode 6, and adheres to the recording paper 8. By such means, the ink droplets adhere and solidify on the recording paper 8 without blurring.

Problems to be Solved by the Invention However, in this method, it is necessary to liquefy the solid ink 1 once, and it takes a considerable amount of time to bring it into operation. There is a method of preheating the solid ink 1 to shorten the rise time, but in this case, power is required even when it is not in use, and the power consumed cannot be ignored. Power consumption can be reduced by using a low melting point solid ink, but in that case, the ink solidified on the recording paper 8 will melt and flow with a slight increase in temperature, making it unsuitable for practical use.

The present invention makes it possible to realize an inkjet recording device that does not cause ink bleeding on recording paper even on plain paper other than a special paper board, and does not require a heating and melting process, which is a disadvantage of conventional methods using solid ink. The purpose is to

Means for Solving the Problems In order to achieve the above object, the present invention uses ink that hardens with moisture in the air, and immediately after the ink is ejected from the head, moist air is applied to the ink to reduce its viscosity. The above problem is solved by means of increasing the height.

Effect of the present invention With the above-described structure, immediately after ejecting a low-viscosity liquid ink that is unlikely to cause clogging, a humid air flow that has a curing effect due to a polymerization reaction is applied to the ink, so that the ink is cured before it adheres to the recording medium. can increase the viscosity. This action makes it possible to record ink without clogging the nozzle portion and without smearing on the recording medium.

Example Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing an inkjet recording apparatus according to an embodiment of the present invention, in which ink droplets 10 ejected from an inkjet head 9 are deposited as ink droplets 11 on a recording paper 1.
Recording paper 12 that flies in the direction and is wound around the recording drum 17
The ink droplets 13 are deposited on the surface and recorded. By exposing the in-flight ink droplets 10.11.13 to a stream of moist air 14, the curing reaction is accelerated and the viscosity is increased. The moist air flow 14 is led from the blower pump 16 through a pipe 15, and the opening of the pipe 15 sends it to the ink droplets 10, 11, 13 from immediately after the ink is ejected until it adheres to the recording paper 12, and the ink in the inkjet head 9. The opening is so that it will not be hit. Further, the nozzle opening of the inkjet head 9 is completely exposed to dry air when the inkjet head 9 is not in operation, to prevent the head nozzle from curing.

The liquid ink, which is cured by the humid air flow 14, is mainly composed of methyl α-cyanoacrylate monomer, which has a high curing speed, and contains trace amounts of a polymerization inhibitor (e.g., hydroquinone), a stabilizer (e.g., sulfur dioxide), a plasticizer, etc. A composition with a viscosity of several centipoise was used. After the ink was ejected, the ink was cured by polymerization several milliseconds before it adhered to the recording paper 12, and its viscosity increased, so that it adhered to the recording paper 12.

The inkjet head 9 is preferably a so-called on-demand type inkjet head that ejects ink by applying a recording signal to a piezo vibrator as described in Japanese Patent Publications No. 53-12138, No. 5345698, etc. , or Special Publick No. 62-4858
A method using electrostatic force and air flow described in Publication No. 7 can be used.

Effects of the Invention As described above, the present invention uses a cyanoacrylate liquid ink that has low viscosity and does not easily clog, and ejects it from an inkjet head, and immediately after that, a stream of humid air is applied to the ink. It causes a polymerization reaction on the ink, causing a hardening effect on the ink and increasing its viscosity before it can be applied to recording paper. As a result, it is possible to realize a full multi-nozzle inkjet recording apparatus that can perform recording without any ink smearing or clogging of nozzles even when using plain paper.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an inkjet device according to an embodiment of the present invention, and FIG. 2 is a sectional view showing the structure of a conventional inkjet head using solid ink. 9... Inkjet head, 10. 11. 13
... Ink droplet, 12 ... Recording paper, 14 ... Moist air flow, 15 ... Pipe, 16 ... Air pump, 1
7... Recording drum.

Claims (4)

[Claims] (1) An inkjet head that discharges liquid ink;
An inkjet recording apparatus characterized by comprising means for applying a humid air flow to flying ink ejected from the inkjet head. (2) The means for applying a humid air flow consists of a blower pump that blows humid air and a pipe that guides the humid air, and the opening of the pipe extends into the space from immediately after the ink droplets are ejected until they adhere to the recording medium. The inkjet recording device according to claim 1, wherein the inkjet recording device is open. (3) The inkjet recording apparatus according to claim 1, wherein the outside of the inkjet head is sealed with dry air when the inkjet head is not in operation. (4) The inkjet recording apparatus according to claim 1, wherein the liquid ink is an ink containing a methyl α-cyanoacrylate monomer as a main component.