JPH02198851A - Ink-jet recording head - Google Patents

Abstract

PURPOSE:To bring nozzles to a multiple state, and to increase density by concentrating and arranging one each nozzle tube body at specified positions with high density, disposing other each injection unit at other locations and communicating and connecting each nozzle tube body and each ink pressure chamber through flexible connecting tube bodies at 1:1 ratio. CONSTITUTION:Ink pressure chambers 5, adhesives 4 for the flow path tubes 3 of flexible tubes connected to the chambers 5, ink supply paths 6 and an ink fountain 7 are formed onto both surfaces of a cavity plate 1 as grooves. Narrow filter flow paths 8 are shaped to sections connecting the ink supply paths 6 and the ink fountain 7. Insular protrusions 9 for preventing the sag of a diaphragm 10 are formed for smoothing the flow of ink in the inlets and outlets of the ink pressure chambers 5. The flow path tubes 3 are bonded with the tube bonding groove 4 sections of the cavity plate 1, and the diaphragm 10 is stuck. Ink nozzles 2 and the ink pressure chambers 5 can be connected at 1:1 through the flow path tubes 3, and the ink nozzles 2 are concentrated and arranged to a nozzle plate 11, thus acquiring an ink-jet recording head, which is brought to a multi-nozzle state having excellent injection characteristics and density of which is increased.

Description

[Detailed description of the invention] [Industrial application field]

The present invention particularly relates to an inkjet recording head with multi-nozzle design and high density nozzles.

[Conventional technology]

Conventionally, a method of recording by ejecting ink from fine nozzle holes and depositing it on a recording medium such as paper is known as an inkjet recording method. One of the principles behind this is the on-demand type inkjet recording head. This type of inkjet recording head has a plurality of ink nozzles formed by etching or machining on a glass or metal plate, as shown in Figure 3, which is a plan view, and Figure 4, which is a side sectional view. 22. Injection channel 23. Ink pressurization chamber 25. After the cavity plate 21 forming the ink supply path 26 and the ink reservoir 27 and the diaphragm 29 are laminated and integrated, a piezoelectric element 30 as an electromechanical transducer is bonded to a position facing the ink pressurizing chamber 25. It has a similar structure. In such a structure, when a voltage as an electric signal is applied to the piezoelectric element 30, the diaphragm 29 moves into the ink pressurizing chamber 25.
The ink is displaced inward and rapidly reduces its volume, and ink corresponding to that volume is ejected from the ink nozzle 22, which becomes ink droplets that are spotted on the recording paper and printed.

[Problem to be solved by the invention]

As explained above, in the conventional technology, the ink nozzle 2
If a large number of ink nozzles 2 are to be concentrated at high density, the length of the ejection flow path 23 from the ink pressurizing chamber 25 of the ink nozzle 22 located on the outside inevitably becomes long.
Fluid resistance increases. For this reason, each ink nozzle 22
The ejection characteristics of the ink may vary, and in extreme cases, a certain ink nozzle 22 may become unable to eject. Further, in the vicinity of the nozzle concentration area, the outer jet flow path 23 must be bent at a steep angle, resulting in large resistance, which may result in a decrease in ink jetting force. In order to overcome this large resistance, it is necessary to increase the capacitance of the piezoelectric element 30, which necessarily requires a larger capacitance of the piezoelectric element 30. This leads to an increase in the size of the ink pressurizing chamber 25 and prevents the ink nozzles 22 from becoming smaller and more highly integrated. Furthermore, this also leads to deterioration of the piezoelectric element 30 due to an increase in applied voltage. Furthermore, for these reasons, there are many restrictions on the arrangement of the ink pressurizing chambers 25, and the number of ink nozzles 22 is also limited. Even if the ink nozzle 2 is arranged in a fan shape as shown in FIG.
The limit for 2 is 15 to 18 pieces. An object of the present invention is to provide an inkjet recording head that solves the problems of the conventional technology and has multiple nozzles and a high density.

[Means to solve the problem]

In order to solve this problem, an inkjet recording head according to the present invention includes a substrate formed as a groove in which a common ink reservoir and a plurality of ink pressure chambers communicate with each other, and an adhesive bonded to the groove side of this substrate. and a diaphragm on which a piezoelectric actuator is provided at a position facing each of the ink pressurizing chambers on a surface opposite to the substrate; and a plurality of nozzle pipe bodies for ejecting ink; ; a flexible connecting tube for connecting each of the nozzle tubes and each of the ink pressurizing chambers in a one-to-one communication manner;

[For use]

The nozzle pipe bodies on one side are arranged in high density at a predetermined location, and the injection units on the other hand are arranged in different locations, for example, in multiple stages.
Arranged in multiple rows or combinations thereof. Since each nozzle tube body and each ink pressurizing chamber are connected one-to-one through the flexible connecting tube body, ink is ejected from each corresponding nozzle tube body by driving each piezoelectric actuator.

【Example】

Embodiments of the inkjet recording head according to the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of essential parts of this embodiment, and FIG. 2 is a side sectional view of the ink nozzle shown in FIG. 1. In FIGS. 1 and 2, an ink pressurizing chamber 5 is provided on both sides of a cavity plate l serving as a glass substrate, an adhesive groove 4 for a flow path tube 3 formed of a flexible tube connected thereto, an ink supply path 6, and an ink pressurizing chamber 5. The reservoir 7 is formed as a groove by photoetching or the like. Furthermore, a narrow filter channel 8 is provided at the portion connecting the ink supply channel 6 and the ink reservoir 7.
This is provided. In addition, in order to smooth the flow of ink at the inlet and outlet of the ink pressurizing chamber 5, island-like protrusions 9 are provided to prevent the diaphragm lO from sagging. The channel tube 3 is bonded to the tube bonding groove 4 of this cavity plate 1, and the diaphragm 10 is bonded thereto. Vibration plate 10
A piezoelectric element 12 is fixed at a location facing the pressurizing chamber 5 . Further, the ink nozzles 2 are attached to the nozzle plate 11 in a concentrated manner. In this embodiment, the flow path pipe 3 and the ink nozzle 2
It is made of Teflon tube. For example, the ink nozzle 2 has an inner diameter of 50 μm and an outer diameter of 0.3 m.
A heat-shrinkable tube (initial inner diameter: 0.76 ffia+, inner diameter after shrinkage: 0.3 nua) is used for the tube m and the flow path pipe 3. First, the left opening (the second
(see figure), fit the ink nozzle 2 into the 150-180°
Heat to C to shrink and firmly bond the two together. The right end of the channel pipe 3 is fitted into the adhesive groove 4, and the diaphragm 10 whose surface is thinly coated with Teflon is placed on the cavity plate 1 and heat-pressed at around 250°C. A structure in which the cavity plate 1 and the diaphragm 10 including the piezoelectric element 12 are fixed together corresponds to the injection unit in the invention. In the embodiment shown in FIGS. 1 and 2, the injection unit is one
Although it is only one set, multiple sets of this injection unit can be arranged in multiple stages,
That is, it is possible to stack them perpendicularly to the surface of the cavity plate 1, to arrange them in multiple rows, that is, in rows in the direction of the surface of the cavity plate 1, or to arrange them in a composite form of multi-stages and multi-rows. In the illustrated embodiment, the ink pressurizing chamber 5. The diaphragms 10 are provided on both sides of the cavity plate 1, but of course they may be provided on only one side if the number is not necessary. In this way, the ink nozzles 2 and the ink pressurizing chambers 5 can be connected one-to-one via the wave path pipes 3 having a length of 10 to 20+++*, and the ink nozzles 2 can be concentrated on the nozzle plate 11. It is possible to obtain a multi-nozzle, high-density inkjet recording head with good jetting characteristics at a pitch of 0.3 tsm and 40 nozzles.

【Effect of the invention】

As explained above, in this invention, each of the nozzle tubes on the - side is arranged in a high density at a predetermined location, and each injection unit on the other side is arranged at a different location, and each nozzle tube and each ink Since they are connected one-to-one to the pressure chambers via the flexible connecting tubes, ink is ejected from the corresponding nozzle tubes by driving each piezoelectric actuator. Therefore, the present invention has the following superior effects compared to the conventional technology. (1) Multiple nozzles and higher density can be achieved. (2) Since the connecting pipe body is flexible, its length, that is, the ink flow path length, can be made as short and uniform as possible by free spatial arrangement.In other words, the flow resistance can be made small and uniform. be able to. Therefore, the voltage required to be applied to the piezoelectric actuator can be lowered, and the ink pressurizing chamber can be made smaller, and the recording head can be made smaller. (3) Related to the previous item, since the ink jetting strength from each nozzle can be made uniform, the recording becomes even and easy to see.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the main part of the embodiment according to the present invention, Fig. 2 is a side sectional view thereof, Fig. 3 is a plan view of the main part of the conventional example, and Fig. 4 is a side sectional view thereof. . Symbol explanation 1: Cavity plate, 2: Ink nozzle, 3: Channel pipe, 4
: Adhesive groove, 5: Ink pressure chamber, 6: Ink supply path, 7:
Ink reservoir, 1o: Vibration plate, 11: Nozzle plate, 1
2: Piezoelectric element.・~ Figure 1 Ryo Figure 2

Claims (1)

[Claims] 1) A substrate formed as a groove in which a common ink reservoir and a plurality of ink pressurizing chambers communicate with each other, and each ink pressurizing chamber is bonded to the groove side of this substrate and on the opposite side to the substrate. one or more sets of injection units having a diaphragm provided with a piezoelectric actuator at a position facing the pressure chamber;
An inkjet recording characterized by comprising: a plurality of nozzle pipe bodies for ejecting ink; and a flexible connecting pipe body for connecting each of the nozzle pipe bodies and each of the ink pressurizing chambers in a one-to-one communication manner. head.