Ink jet print head

Abstract

An ink jet print head comprises a substrate formed with a heating resistor, an ink path defining member for defining an ink supply path, and an orifice plate, and in the orifice plate, there is formed an ink outlet at the position opposing the heating resistor. Further, a heating zone surrounding the heating resistor is formed at the position corresponding to the heating resistor of the ink supply path. The channel resistance of the ink supply path is set so that a relationship is established between a quantity q of the discharged ink drop, a sectional area A of the ink outlet, and a maximal projection h that a meniscus of the ink has when it projects from the ink outlet after it has restored the exit level from a retreat position it had after the drop of the ink had been discharged such that <DEL-S DATE="20011127" ID="DEL-S-00001">0<h<0.3q / A<DEL-E ID="DEL-S-00001"> <INS-S DATE="20011127" ID="INS-S-00001">0<h<0.25q / A<INS-E ID="INS-S-00001">. Consequently, there is obtained a high-speed printing of high quality without dispersion.

Description

BACKGROUND OF THE INVENTIONThe present invention relates to an ink jet print head for discharging ink drops from ink outlets by use of thermal energy.Description of the Related ArtRecently, in contrast with the wire dot printing methods, non-impact recording method is attracting interest became the recording noise level is negligible. In particular, an ink et recording method is attractive as it permits high-speed recording on ordinary paper without the need of a deposition treatment on the paper side. In the field, therefore, aiming at an optimal ink discharge performance, various approaches have been made, with associated implementations.In the ink jet recording method, a recording is effected with discharged droplets of recording liquid, called "ink" deposited on a recordable material. This method is categorized into several systems according to the manner in which the drops of recording liquid are formed.FIG. 1 illustrates a bubble jet recording system as a conventional example....

AI Technical Summary

Benefits of technology

It therefore is an object of the present invention to provide an ink jet print head with criteria such as on an sectional area of an ink outlet and a fluid resistance of an ink supply path to achieve an optimal high-speed ink discharge with an increased reliability and an improved cost effect, without additional elements.

Thus, the larger the diameter of the ink outlet is, the smaller the mean momentum becomes, with a reduced frequency of occurrence of an overshooting ink meniscus.

According to the present invention, after an ink drop is discharged from an ink outlet by grown bubbles, the projection of a meniscus at ink refill is kept small by optimizing the channel resistance value of an ink supply path.

Therefore, the periodic damping time of the meniscus becomes short, and the unfavorable effect to be caused at the subsequent discharge is avoided.

Moreover, in the case in which the sectional area of the ink outlet is set large within the predetermined range, the projection of the meniscus at ink refill becomes small, and the damping time of the vibration of the meniscus becomes short.

Further, in a constitution in which the relation between the restoring time of the meniscus and the minimum driving period of a print head is set within the predetermined range, no dead time exists before the subsequent discharge without an undesirable deformation of the discharged ink drop, and the discharge interval becomes short.

Problems solved by technology

Such satellites adversely affect the printing.

This causes an undesirable deformation of an ink drop and an undesirable development of low-speed satellites, resulting in a reduced quality of recording.

Further, some volume of ink may flood over a surface area around the ink outlet 38, causing an ink drop to be discharged in an oblique direction, or bubbles to be involved, stopping the discharge, with a reduced reliability of recording.

A probable solution to such problems may include entering subsequent discharge after a sufficient damping of vibration, which however is inconsistent with an intended high-speed recording.

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