JPH0137277B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid supply element for a liquid ejecting device such as an inkjet recording device that ejects liquid to record characters and figures, and is aimed at improving the earlier application filed by the present applicant. It is. An explanation will be given below using the applicant's prior application as an example.

For example, in a device such as an X-Y recorder or a line printer in which a recording head (hereinafter referred to as a head) having an ejection port of a liquid ejecting device is scanned, a supply pipe connected to the head that supplies liquid moves accordingly. However, if the pressure fluctuations in the liquid in the supply pipe that occur due to this are propagated to the head, it will have an adverse effect on the head. A device for alleviating this pressure fluctuation will be explained.

FIG. 1 shows a structure in which the liquid supply pipe 2 is formed into a loop shape in order to alleviate the inertial force of the liquid within the liquid supply pipe 2, as proposed by E. STEMME et al.
(Division of Computer Research, Research
Report No. 8 1972 Chalmers University of
In this system, the liquid supply pipe 2 is branched into two routes for the head 1 via the fluid supply element 3, and arranged in a symmetrical shape that looks like two U-shaped liquid supply pipes combined. The length from the left end of the liquid supply pipe 2 to the right end is at least 1/1 of the moving range of the head 1.
2 or more are required. In a liquid supply pipe having such a shape, when the head 1 moves from side to side as shown in FIGS. 2B and 2C, the inertial force of the liquid tends to be offset between the left and right sides, so that fluctuations in the pressure of the liquid are easily reduced.

Next, an example of the structure of the fluid supply element 3 is shown in FIG. The liquid communication passage 4 and the liquid communication passage 5 have orifices 8 and 9 provided in thin orifice plates 6 and 7, respectively, and these two orifices 8,
9 is a thin liquid supply layer 10 that supplies liquid to the head.
are connected via.

Now, in FIG. 1, head 1 is scanned to the left,
Considering the state shown in Fig. b where the liquid is stopped at the end, an inertial force is generated in the liquid in the liquid communication passage 5 in Fig. 2 and in the liquid supply pipe on the right side connected thereto. The inertial force is expressed as the sum of static pressure and dynamic pressure. As shown in FIG. 2, the liquid communication passages 4, 5 and the orifice 8,
If the ratio of the cross-sectional areas of 9 is large, the velocity of the liquid in the orifices 8, 9 is significantly increased compared to the liquid communication channels 4, 5. Therefore, orifice 8,
The dynamic pressure within 9 increases. Assuming that Bernoulli's equation holds approximately true, static pressure + dynamic pressure = constant, so static pressure will decrease by the amount that dynamic pressure increases. Therefore, the static pressure in the thin liquid supply layer 10 existing between the orifices 8 and 9 is reduced by the communication passage 5.
This shows a value lower than the static pressure at . Since the static pressure in the thin liquid supply layer 10 indicates the pressure propagated to the head, this fluid supply element 3 can alleviate pressure fluctuations in the liquid propagated to the head. The same theory as above holds true even when the head 1 in FIG. 1c remains at the right end. Therefore, by using the liquid supply pipe 2 shown in FIG. 1 and the fluid supply element 3 shown in FIG. 2, the pressure fluctuations at both ends b and c in FIG. 1 can be alleviated.

Figure 3 shows that to further improve this effect,
Liquid chambers 11, 12, 13 are provided between the liquid communication passages 4, 5 with the liquid supply pipe 2 and the orifices 8, 9, and between the passages communicating between the thin liquid supply layer 10 and the head 1.
The purpose is to further alleviate pressure fluctuations in the liquid chambers 11, 12, and 13.

Parameters that greatly influence the characteristics of this fluid supply element include the orifice diameter and the thickness of the liquid supply layer 10. In particular, since the thickness of the liquid supply layer 10 is several tens of μm, it is extremely difficult to control it, which has been a major problem during manufacturing. FIG. 4 shows the relationship between the thickness of the liquid supply layer 10 and the pressure fluctuations propagated to the head. ±ΔP on the vertical axis indicates an allowable range within which pressure fluctuations will not have an adverse effect on the head. Fourth
As can be seen from the curve in the figure, when the pressure fluctuation is around 0, the slope of the curve is steep, so the range of effective thickness of the liquid supply layer becomes narrow.

As described above, the range of the effective thickness of the liquid supply layer is narrow, and the thickness is extremely thin, making it difficult to manufacture, and the characteristics of the fluid supply element itself have large variations, resulting in poor yields.

The present invention solves the above-mentioned drawbacks and provides a liquid supply element with stable characteristics. The present invention
A removed portion is provided around the two orifice plates, and a portion of each removed portion is connected to the two orifice plates via a spacer that has the removed portion provided in the center including the orifice portion. It is characterized by: The present invention will be described in detail below with reference to examples.

FIG. 5 shows an example of the shape of the orifice plate and spacer of the present invention. The material used was stainless steel.
The two orifice plates 6 and 7 each have 4 holes around them.
There are several removal sections. The spacer 14 has its central part removed, and four convex parts are provided from the periphery, so that the thickness of the thin liquid supply layer formed by inserting the spacer 14 is constant even near the central part of the orifices 8 and 9. Efforts have been made to keep it. If the removed portions of the orifice plates 6, 7 and the spacer 14 are formed by etching, the result will be extremely accurate, and this is an effective means when considering mass production. 2
Since the orifice plates 6 and 7 and the spacer 14 are each thin, their outer shapes are made to be the same in order to obtain strength when the three plates are joined together. The method for joining the three plates 6, 7, and 14 is to use adhesive, so that the adhesive layer is 10 μm thick.
m to 100 μm, and the thickness of the liquid supply layer became unstable, so metal bonding was performed. The metal bonding method is 3
Gold is vapor-deposited to a thickness of 2 to 3 μm on the surfaces of the plates 6, 7, and 14, and they are stacked and pressed together, heated at high temperature in a vacuum furnace, and bonded. The thickness of the liquid supply layer formed by this method can be finished with an accuracy within ±several μm.

FIG. 6 shows a liquid supply element according to an embodiment of the present invention, which uses the three plates 6, 7, and 14 shown in FIG. 5 joined together. The liquid flows in the direction of the arrow,
It passes through the liquid supply layer 10 and hits the inner surfaces of the removed portions of the orifice plates 6, 7 and spacers 14, and is divided into left and right sides and guided to the liquid chamber 13, so that the removed portion acts as a fluid diode, further enhancing the effect. This is one of the features of the present invention.

As described above, in the present invention, a removal section is provided around two orifice plates, and the two plates are connected via a spacer in which a removal section is provided at the center including the orifice, thereby supplying liquid. This liquid supply element is characterized in that layers are formed and the respective removal parts are connected to each other in at least one part, and the liquid supply element has the following effects.

(1) The thickness of the liquid supply layer, which greatly influences the characteristics of the fluid supply element, can be controlled uniformly over the entire area with extremely high precision.

(2) Since the orifice plate is joined at least at its outer periphery with a spacer in between, it has excellent strength and reduces the risk of breakage.

(3) The removed portion of the orifice plate and spacer serves as a fluid diode, further enhancing the effectiveness of the liquid supply element.

[Brief explanation of drawings]

1a, b, and c are schematic diagrams of a liquid supply pipe system of a conventional liquid injection device; FIGS. 2 and 3 are sectional views of a liquid supply element according to an earlier application filed by the same applicant; The figure is a graph showing the relationship between the pressure fluctuation propagated to the head and the thickness of the liquid supply layer. FIG. 6 is a sectional view of a liquid supply element in one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Head, 2... Liquid supply pipe, 3... Fluid supply element, 4, 5... Liquid communication passage, 6, 7...
Orifice plate, 8, 9... Orifice plate, 10...
Liquid supply layer, 11, 12, 13...liquid chamber, 14
……Spacer.

Claims (1)

[Claims] 1 first and second having at least one opening
A liquid chamber is divided and formed by two plates facing each other, at least a pair of orifices are bored in the center of each of the two plates, and a thin layer is formed between the orifice and the two plates. In the liquid supply element, the first and second liquid chambers are in communication with each other through the liquid supply element, and the thin layer is in communication with at least one opening that communicates with the outside.
The thin layer is formed by joining the two plates via a spacer, and an opening is formed in each of the two plates at their periphery and approximately at the center including a portion of the spacer facing the orifice. A liquid supply element characterized in that the thin layer and the opening communicating with the outside communicate with each other.