JPH02155651A - Ink jet head - Google Patents

Abstract

PURPOSE:To prevent the unnecessary deposition of imperfectly emitted ink on an ink emitting surface by allowing the nozzle outlet of the emitting surface to protrude. CONSTITUTION:A part 1a of a nozzle plate 1 has an orifice shape and a nozzle outlet protrudes from an ink emitting surface. The protruding quantity of the nozzle outlet is pref. 10-150mum from experimental results and the pref. width of the protruding part is 150mum or less. Imperfectly emitted ink 9 is not separated from the nozzle plate 1 after the emission of ink to be accumulated on the ink emitting surface 1-b but, when the accumulation of the ink is generated, the ink is not accumulated on the ink emitting surface 1-b in a definite amount or more from the relation of the surface tension of the ink with the nozzle plate 1 to transfer to a non-protruding surface 1-c and, when the accumulation of the ink on the non-protruding surface 1-c is further advanced, the imperfectly emitted ink 9 is recovered under gravity.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to inkjet print recording.
In particular, the present invention relates to an inkjet head that performs printing by driving a pressure generator in ink to eject ink from a nozzle orifice.

[Conventional technology]

Conventionally, as shown in Japanese Patent Publication No. 60-8953, for example, the nozzle shape of the ink ejection surface was flat, and a piezoelectric transducer was configured to have a slight gap on the back surface of the nozzle, and the piezoelectric transducer was inserted through a support member. It was locked and locked.

[Problem to be solved by the invention]

However, in the above-mentioned conventional technology, since the ink ejection surface is flat, incompletely ejected ink accumulates at the nozzle outlet of the ink ejection surface, resulting in an obstacle when ejecting the ink. An object of the present invention is to solve these problems, and to provide stable ink ejection and good print quality.

[Means to solve the problem]

It is characterized by the nozzle outlet protruding from the ink ejection surface.

[Effect]

According to the above configuration of the present invention, since the area in which the incompletely ejected ink can accumulate at the nozzle outlet is extremely small and constant, it is obvious that the incompletely ejected ink moves to the non-projecting surface.

〔Example〕

The structure and features of the inkjet head according to the present invention will be explained below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of an embodiment of an inkjet head according to the present invention, in which 1 is a nozzle plate, and a portion 1a of the nozzle plate 1 is in the shape of an orifice. A portion lb of the nozzle plate 1 is an ink ejection surface from which nozzle outlets protrude. According to experimental results, the above-mentioned protrusion fi7 of the nozzle outlet is preferably 10 μ or more, and the width 8 of the protrusion is preferably 150 μ or less.

The nozzle plate 1 can be easily formed, for example, by electroforming. 2 is a gap agent, and adhesive 3 is used to maintain a constant gap between the vibrator, which is composed of a diaphragm 4 (for example, nickel), a piezoelectric element 5 (PZT), and an electrode 6 (for example, nickel, chromium, or gold) and the nozzle plate 1. is held through. A portion 3a of the adhesive 3 is overlapped and bonded in the direction of arrow A on the ink discharge side.

FIG. 2 is a conceptual diagram showing a state in which incompletely ejected ink 9 accumulates. (a) shows the occurrence and initial accumulation of incompletely ejected ink 9. Incompletely ejected ink 9 refers to ink that remains on the ink ejection surface 1-b of the nozzle plate 1 without separating from the nozzle plate 1 after ink ejection. (b) further shows that when incompletely ejected ink 9 occurs, the ink and nozzle plate 1
The figure shows how a certain amount or more of ink does not stay on the ink ejection surface 1-b but moves to the non-projecting surface 1-c due to the surface tension relationship with the surface tension. (c) shows how incompletely ejected ink 9 is recovered due to forces such as gravity as the accumulation on the non-projecting surface 1-c further progresses.

FIGS. 3(a) and 3(b) are application examples of the present invention aimed at improving the mechanical strength of the nozzle plate, and the nozzle plate 1 of FIGS. The nozzle plates shown in FIGS. 3(a) and 3(b) can be easily created by covering the shaded area 10 in FIG. 3 with a resist and further electroforming.

〔Effect of the invention〕

As described above, according to the present invention, since the nozzle outlet is configured to protrude, the ink ejection surface 1 of the incompletely ejected ink 9 is
Unnecessary accumulation at -b can be prevented. In other words, even if there is contact with a very small amount of accumulated incompletely ejected ink 9 during normal ejection of ink, variations in the ejection direction can be extremely reduced and stable and good print quality can be obtained.

Furthermore, when the same orifice shape is required, the thickness of the nozzle plate can be made thinner. For example, when this configuration is manufactured by electroforming, the variation in plate thickness can be reduced due to the thinness, improving orifice shape accuracy. However, the amount of ejected ink is stabilized, which improves print quality, and since it is thin, the manufacturing process time can be shortened, and an inexpensive inkjet printer can be provided.

1... Nozzle plate 2...Gap agent 3...Adhesive 4...Vibration plate 5...Piezoelectric element 6...electrode that's all Applicant: Seiko Epson Corporation Agent, Patent Attorney, Picture Book, Kisanbe (t!! 1 person)

[Brief explanation of the drawing]

Figure 1 is a sectional view showing one embodiment of the present invention, Figure 2 (a)
~(c) is a conceptual diagram showing the accumulation state of incompletely ejected ink;
FIGS. 3(a) and 3(b) are diagrams showing an example of application of the present invention. Figure 2 Figure 3

Claims (1)

[Claims] A plurality of nozzles have piezoelectric transducers arranged in pairs with a certain gap between the nozzles, and by operating the piezoelectric transducers in the ink, the pressure of the ink near the nozzles is increased, and the ink is drawn from the nozzles. An inkjet head for ejecting droplets, characterized in that a nozzle outlet on an ink ejection surface is protruded.