JPS63191644A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To confine influence of breakdown of cavitation within a portion of a heating element, by splitting the heating element into a plurality of parallel sections. CONSTITUTION:In an ink jet recorder, recording liquid drip 25 is delivered through a delivery port 17 by means of foam 24. A substrate 15 where five heating units 26 are arranged in parallel to from a heating element 14. A delivery port board 18 formed with a delivery port 17 and a gap board 16 are employed to form a recording head. Damage of the heating element 14 due to breakdown of cavitation can be found near the position where the foam disappears. Since the heating element 14 is splitted into plural sections, influence of damage can be prevented from extending to the entirety. Furthermore, since the splitted heating unit 26 is constructed into a parallel circuit. breakdown of single heating unit 26 causes no influence on the heating value of other heating unit 26.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a head structure for inkjet recording that ejects droplets by heating the recording liquid and changing its state.

[Conventional technology]

As a conventional example of an inkjet recording device that ejects recording droplets by heating the recording liquid and changing its state, the US II E
The May 1985 issue of WLETT-PACKA RD's Journal introduces the structure of the recording device and recording head in detail, and describes an inkjet recording device that has a simple structure and is capable of high-speed, high-density recording. It is an effective means of achieving this.

[Problem to be solved by the invention]

However, in the above-mentioned technology, when the bubbles generated for ejecting the recording liquid disappear, a high-speed flow is generated against the nearby solid surface, causing damage to the solid surface due to impact (hereinafter referred to as cavitation damage). ), the central part of the heating element is destroyed. Furthermore, if a part of the heating element is damaged by cavity dion destruction, heat generation will be unevenly distributed around the damaged area, causing rapid deterioration such as oxidation, causing the entire heating element to break and the recording head to lose its function. This is the 17ff issue.

The present invention is intended to solve these problems, and its purpose is to provide an inkjet printer HH with high durability.

[Means for solving problems]

The inkjet recording apparatus of the present invention is characterized in that at least a part of the heating element corresponding to one ejection port is divided into a plurality of parts having mutually parallel circuit configurations.

〔Example〕

The present invention will be explained in detail based on examples.

FIG. 1 is a schematic overall diagram showing an embodiment of an inkjet recording apparatus of the present invention.

In FIG. 1, a recording head 1 is guided by a carriage guide 6 and moves in the direction of arrow I while being supplied with recording liquid from a recording liquid tank 5 through a recording liquid supply pipe 12. Inkjet recording is performed on a recording paper 3 that is fed intermittently with a line feed synchronized with 1. Note that 9 is the paper feed motor;
11 is a paper feed gear, 11 is a carriage motor, 10 is a carriage belt, and 7 is a frame of the apparatus.

FIG. 2 is a schematic exploded view showing the structure of the recording head 1 of the ink jet recording apparatus of the present invention.

In FIG. 2, the substrate 15 on which the heating element 14 is formed includes:
Gap plate 16 is installed so that heating element 14 and discharge 018 face each other.
The bottom plate 13 and the recording liquid supply pipe 12 are attached so that the recording liquid is supplied to the gap between the substrate 15 and the discharge outlet plate 17 formed by the gap plate 16. The heating element 14 is connected to the switching element sw through an electrode 19.

FIG. 3 is a sectional view showing the structure of the recording liquid ejecting section of the recording head of FIG. 2. FIG.

In FIG. 3, a heat storage layer 20, a heating resistance layer 21. fii electrode I layer 22, electrode 1 layer 23 are stacked,
The heating resistor layer 21, the first electrode layer 22, and the first electrode layer 23 are etched in the pattern shown in FIG.

In the inkjet recording apparatus of the present invention, the heating element 14 has a second
Electric power is intermittently supplied by the switching element Sw shown in the figure to generate Joule heat, and the recording liquid in contact with the heating element 14 undergoes rapid film boiling, causing bubbles 24 to generate and grow, resulting in a pressure change at the discharge port 17. The recording liquid droplet 25 is ejected.

FIG. 4 is a plan view showing the shape of the heating element of the recording head 1 in one embodiment of the inkjet recording apparatus of the present invention, and FIG. 5 is a plan view showing the shape of the heating element of a conventional inkjet recording apparatus.

An inkjet recording device having a heating element shape shown in FIGS. 4 and 5 was manufactured as follows.

On the Si substrate, 3μ of SiO* is deposited as heat storage fi20.
m, heating resistance 1ff121 T a −S I O
* B is 0, 7 μm 1TI pole I B 22, T amount is 0.058m1 electrode ■ layer, Au is 1.5
Lamination was performed by μm sputtering, and a heating element shape shown in FIGS. 4 and 5 was formed by one step of photolithography.

The heating element 14 in FIG. 4 has a length of 150 μm and a width of 30 μm, and the heating element unit 26 has a capacity of 10 μml? The heating element shown in the figure is 150 mm in length and width, with 5 pieces arranged in parallel at the tl corner.
It is μm. Next, the substrate 15 as described above and a diameter of 60 μm
Temporary 14 x 50 μm discharge port plate 1 with discharge ports 17 formed thereon.
Recording Hepto 1 using 8 and 50 μm gap plate 1G
was formed. The resistance value of the heating element 14 was 50Ω in both cases, and the recording liquid could be stably discharged by applying a pulse of 6 μs at an applied voltage of 20V. Daft is 50% water.
, 47% triethylene glycol, and 3% water-soluble dye are used.

As a result of testing the recording liquid ejecting section at a driving frequency of 3kl-1z using a conventional recording device with a heating element shape shown in FIG.
In 12 out of 50 heating elements 14 were broken by the 5th turn,
When it became impossible to eject the recording liquid, we conducted a similar experiment using the heating element of the present invention shown in Fig. 4.5
All 50 units were able to eject recording liquid up to 100 million times.

After the experiment, we developed the recording device and examined the heating element 14. As a result, we found that the conventional shape of the heating element 14 shown in FIG. It is thought that the damage caused by cavitation fracture grew and caused the fracture. On the other hand, in the case of the present invention shown in FIG. 4, one or two of the five heating element units 26 arranged in parallel were all broken, and Of the 5 pieces, the one in the center is all broken, and 2 pieces from the edge are broken.
In the 50th case, the heating element unit 26 located at the farthest end was broken.

After the experiment, the substrate 13 was placed in water and driven to create bubbles 240.
When we observed the generation and extinction process, we found that bubbles 2 were not found in any of the heating element shapes shown in FIGS.
4 was observed to coalesce into one during the growth process, contract near the center of the heating element 14, and disappear.

From the above results, damage due to cavitation destruction is seen near the disappearing position of the bubble 24 regardless of whether the heating element 14 is divided into multiple parts, and it is clear that the heating element 14 is divided into multiple parts as in the present invention. It can be seen that it is possible to prevent the influence of the damage from reaching the entire heating element 14. Furthermore, the divided heating element units 26 have a parallel circuit configuration, so that one heating element unit 26
Even if the heating element unit 26 is broken, it does not affect the heating poison in other heating element units 26.

6 and 7 are plan views showing the shape of a heating element in another embodiment of the inkjet recording apparatus of the present invention.

It is only necessary that the heating element 14 is divided only at the part that is damaged by cavitation destruction.It is also effective if only a part of the heating element 14 is divided as shown in the fXSe diagram.

Further, as shown in FIG. 7, by arranging the heating element unit 26 avoiding the portion most susceptible to cavitation damage, it is possible to prevent cavitation damage to the heating element. The heating element unit 26 may have a curved shape as shown in FIG. 7 (or it is also possible that there is no heating element unit 26 in the center of the heating elements 14 in FIG. 3. FIG. 8(a) is a sectional view of a heating element of another embodiment of the Inokjet Ki Q design of the present invention,
FIG. 8(b) is a plan view of the heating element of FIG. 8(a).

Even in the case where the heating element 14 and the electrode 19 are covered with a protective layer 27 made of an electrical insulator in order to prevent electrical corrosion caused by the recording liquid in part or all of the layers constituting the heating resistance layer 21 and the electrodes, the protective layer 27 is a caviteller. If the heating element 14 is damaged by the destruction of the protective layer 27, the damage reaches the underlying layer of the protective layer 27, and if the heating element 14 is located there, the heating element 14 will not be damaged by cavitation destruction or electrical corrosion by the recording liquid. break. Even when the protective layer 27 is provided as shown in FIGS. 8(a) and 8(b), the effect of cavity destruction caused by the heating element 14 being divided into a plurality of parts can be avoided.
It can be kept as part of 4.

〔Effect of the invention〕

As described above, according to the present invention, at least a part of the heating element corresponding to one discharge port is divided into a plurality of parts having a parallel circuit configuration, thereby preventing cavitation destruction that occurs when bubbles disappear. It is possible to limit the influence of the heat to a part of the heating element, and furthermore, it is possible to eliminate the influence on the heating element.This makes it possible to manufacture an inkjet recording device with stable recording liquid ejection, reliability, and high durability. It produces the effect of

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the general structure of an inkjet recording apparatus according to the present invention. FIG. 2 is a schematic exploded view showing the structure of the recording head of the inkjet recording device of the present invention. FIG. 3 is a cross-sectional view showing the structure of the recording liquid ejecting section of the recording head of FIG. 2. Fig. 4 shows the inkjet recording according to the present invention, and Fig. 5 shows the conventional inkjet recording g.
FIG. 3 is a plan view showing the shape of the heating element of the device. FIGS. 6 and 7 are plan views showing the shape of a heating element in another embodiment of the inkjet recording device of the present invention. FIG. 8(a) is a sectional view of a heating element in another embodiment of the inkjet recording KH of the present invention. FIG. 8(b) is a plan view of FIG. 8(a). Above 1 w1t Yuto Yatsu V Figure 1 Figure 2 Figure 3 Figure 19: Electric set 26: Da 6 heat rice 9. . Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] In an inkjet recording apparatus that performs recording by heating a recording liquid with a heating element and ejecting recording liquid droplets from an ejection opening corresponding to the heating element due to a change in the state of the recording liquid due to the heating, one of the ejection openings is heated. An inkjet recording device characterized in that at least a part of a corresponding heating element is divided into a plurality of parts having mutually parallel circuit configurations.