JPH05229127A - Nozzle plate and production thereof - Google Patents

Abstract

PURPOSE:To contrive a stable ink flying by a method wherein a nozzle is shaped into a funnel form having a cylindrical part extending at an angle of 1-10 degrees from a minimum-diameter part of an ink delivery port in an ink flying direction and a conical part extending at an angle larger than that of the cylindrical part. CONSTITUTION:A nozzle 2 in a nozzle plate 1 is shaped into a funnel form having a cylindrical part 2-a extending at an angle of 1-10 degrees from a minimum-diameter part of an ink delivery port 2-c in an ink flying direction and a conical part 2-b extending at an angle larger than that of the cylindrical part 2-a. A meniscus 3 (a contact point a) of ink 4 is formed while having its tangent line on an edge of the conical part 2-b which functions as a lead-in part for the ink 4. Because the edge of the conical part 2-b is a straight line, the contact angle of the tangent line is kept constant. The contact point of the meniscus 3 with the conical part 2-b changes with a change in printing state or physical properties of ink. However, the shape of a meniscus 3-a of the ink 4 changing in contact position from the contact point (a) to a contact point (b) does not greatly differ from the shape of the meniscus 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nozzle plate for an ink jet printer and a method for manufacturing the nozzle plate.

[0002]

2. Description of the Related Art There are several types of ink jet printer heads, in which an ink passage communicating with an ink pressurizing chamber is covered with a nozzle plate so that ink is ejected from nozzles opened in the ink passage portion. In order to discharge the pressurized ink correctly in the axial direction of the nozzle, the structure is such that an arc-shaped ink introduction portion 102-b is formed by dividing a circle into four as shown in FIG. 7 by electroplating by plating. Nozzle 10 having ink ejection port 102c
The nozzle plate 101 on which 2 is formed is used. When the ink is ejected from the nozzle in the inkjet head, a meniscus is formed in the ink introduction portion so as to have a contact point and a tangent line. If the shape of this meniscus does not become a constant shape, the ink flight is not stabilized. However, in such an arc-shaped ink introducing portion 102, the meniscus 103 (contact point a) and the meniscus 103a (contact point b)
As can be seen by comparison with, since the arcs have tangent lines with different angles at each point, the shape of the meniscus 3 is not stable due to the way the ink 4 contacts. The same applies because the contacting method changes even when the physical properties of the ink, particularly the viscosity, change due to temperature changes. That is, the ink flight is not stabilized in the arc-shaped ink introducing portion 102.
In addition, since the nozzle plate is produced by a chemical method such as plating, it is very difficult to control the minimum diameter portion of the ink ejection port 102c, and the productivity is poor, so that the cost is high.

There is also a method disclosed in Japanese Patent Publication No. 1-26837, but in order to form such a nozzle, a punch having a unilateral curvilinear expansion has a volume that swells when the punch abuts. It comes into contact with a metal plate mounted on a die having a recess having a matching volume, and the bulging portion formed is ground to obtain a desired shape. However, in this method, for example, when the punch lowering accuracy, especially the bottom dead center accuracy is incorrect and the tool is lowered too much, the volume of the bulging portion becomes larger than the recess of the die, compressing the punch and accelerating wear, and in the worst case. Is a problem that the small diameter part of the punch is broken, or if the metal plate has spring properties, the nozzle shape formed immediately after raising the punch contracts and the nozzle shape is stable. There is a problem that it is not possible to achieve high precision. In addition, the volume of the bulging portion also changes due to changes in the thickness of the metal plate, punch and die processing accuracy, and the above problems occur, making it impossible to manufacture a stable nozzle plate at low cost. is there.
Further, since the single-leaf curvilinear introducing portion has the shape of a circular arc as described above, ink flight is not stabilized.

[0004]

SUMMARY OF THE INVENTION Therefore, the present invention is intended to solve such problems, and an object thereof is to provide a low-cost and highly-accurate nozzle plate that can be stably produced. is there.

[0005]

In an ink jet head having a substrate having an ink flow path, a means for ejecting ink, and a nozzle plate having nozzles for ejecting the ink, the nozzle of the nozzle plate is 1 degree to 10 degrees from the smallest diameter portion of the ink ejection port with respect to the ink flight direction
Of a funnel shape having a cylindrical portion having a divergence angle of at least 10 degrees and a conical portion having a divergence angle at least larger than the divergence angle of the cylindrical portion, and a method of manufacturing the nozzle plate having the nozzle has a thickness of several hundred microns. In forming the funnel-shaped nozzle having a minimum diameter of several tens of microns with respect to the following metal sheet, a punch having a funnel shape corresponding to the nozzle shape,
A hole slightly larger than the small-diameter portion at the tip of the punch and a chamfered portion having a volume smaller than the volume at which the metal sheet bulges when the punch abuts and penetrates the metal sheet are provided at the hole entrance. A swelling portion formed by abutting the punch against the metal plate pressed between the stripper plate holding the die and guiding the large-diameter shaft portion of the punch and the die is removed by grinding. The feature is that the nozzle shape is obtained.

[0006]

An embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a view showing the nozzle plate and nozzle shape of the present invention. 2 is a nozzle, 2-a is a cylindrical part, and 2-b is a conical part as an ink introducing part. The nozzle plate 1 is formed by forming a large number of the nozzles 2. Reference numeral 3 denotes a meniscus (contact point a) of the ink 4, and the conical portion 2 functions as an introduction portion of the ink 4.
It is formed to have a tangent line on the line of -b. This tangent line maintains a constant contact angle because the traverse of the conical portion 2-b is straight. As a result, the shape of the meniscus 103-a in the state where the contact position of the ink 4 with the conical portion 2-b changes from the contact point a to the contact point b is similar to that of the meniscus 3 and there is no significant difference. Formation can be stabilized. This will be compared with the nozzle plate 101 manufactured by the electroforming method shown in FIG. 7 showing a conventional example. Reference numeral 103 denotes a meniscus (contact point a), and reference numeral 103-a denotes a state in which the contact position of the meniscus (contact point b) between the ink introducing portion 102 and the ink 104 changes from the contact point a to the contact point b. Since the ink introducing portion 102 is formed by an arc, the angle of the tangent line changes depending on the contact position of the ink 4, and the meniscus 3-a of FIG. 1 and the meniscus 103 of FIG.
As can be seen by comparison with −a, the meniscus 1 of FIG.
The deformation of the meniscus 103-a with respect to 03 is larger than the deformation of the meniscus 3-a with respect to the meniscus 3 of FIG.

The stabilization of the shape of the meniscus 3 has a great influence on the stabilization of the characteristics of the ink jet head, which will be described with reference to FIGS. 2, 3 and 4. FIG. 2 shows a state inside the nozzle before ink ejection. In this state, for example,
When the ink ejecting means 5 typified by an upper lid member for transmitting vibrations and a piezoelectric element mounted on the upper part of the flow path, or a heating element mounted on the flow path operates, the ink droplets 4 are ejected as shown in FIG. -A discharges. FIG. 4 shows a state after the ink droplet 4-a is ejected, and the ink vacancy unit 4-b corresponding to the ejected amount.
(Hatching part) is formed. This air force section 4-b is returned to the original meniscus state by reforming the meniscus 3. For this reason, whether or not the shape of the meniscus 3 accurately returns has a great influence on ink flight. When the shape of the meniscus 3 changes each time, the weight of the ink flying at one time changes,
Since the resistance force from the meniscus 3 when the ink is ejected is changed, the ink ejection speed is changed and the print quality is seriously affected. The contact point of the meniscus 3 with the conical portion 2-b also changes depending on the printing state during continuous ink ejection or intermittent ink ejection, or due to changes in the ink physical properties due to external factors such as temperature or humidity. As described above, the ink introduction portion is formed into a conical shape so that the shape of the meniscus 3 does not change significantly with respect to a slight change in the contact point, which is very effective in ink flight stability.

5 and 6 are conceptual views of processing when forming nozzles on the nozzle plate of the present invention. 10 is nozzle 2
Is a punch having a shape suitable for
It is composed of a columnar portion 10-b. 12 is a die, which is a hole 13 slightly larger than the small-diameter portion at the tip of the punch 10;
Nozzle plate raw material 1-a in which punch 10 is metal at 3 inlets
The chamfered portion 14 has a volume smaller than the volume (bulb 16 + scrap 15) that swells when coming into contact with or penetrating. As shown in FIG. 6, the punch 10 is formed on the metal nozzle plate material 1-a having a thickness of several hundreds of microns or less, which is pressed and sandwiched between the die 12 and the stripper plate 11 for guiding the large-diameter shaft portion 10-c of the punch 10. The scraps 15 drop into the holes 13 by contacting and penetrating with each other to form burrs 16. By removing this flash 16 by grinding, the nozzle shape as shown in FIG. 1 can be obtained. According to this method, since the punched dust 15 comes off, the force for compressing the tip of the punch 10 is reduced, so that the tip portion of the punch 10 seen in the conventional example is compressed to break the columnar portion 10-a. No such thing happened. Further, the bulging portion remaining on the nozzle plate 1 is only the flash 16, and in the conventional example, the volume required for grinding is the volume of the scraps 15 and flash 16 combined, and I was able to save a lot of time. Since the tip of the punch 10 has a composite shape of a cylindrical shape and a conical shape, complicated arc-shaped curve machining is not required, so that the punch machining can be performed with high accuracy and the machining can be simplified. Since the punch 10 has a divergence angle of up to 10 degrees, the resistance when the punch 10 penetrates the nozzle plate 1-a or when the punch 10 is pulled out can be reduced, which is effective in reducing the wear of the punch 10. As a result, an inexpensive and highly accurate nozzle plate can be manufactured. However, if the divergence angle is 10 degrees or more, the diameter of the ink ejection port 2-c may change depending on the descending accuracy of the punch. If the divergence angle of the columnar portion 2-a is θ, the formula (ink ejection port 2-c Change amount = 2 × descent error of the punch 10 × tan θ), the dimensional change of the diameter of the ink ejection port 2-a of the cylindrical portion 2-a of the nozzle becomes large, and therefore the spread angle is preferably 10 degrees or less.

When an ink jet head using the nozzle plate of this embodiment was manufactured, it was possible to obtain an ink jet head of high print quality with extremely stable ink ejection speed and ink weight.

[0011]

As described above, by carrying out the present invention, a high-performance nozzle plate can be easily processed with high precision.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a nozzle shape embodiment of the present invention.

FIG. 2 is a diagram showing the behavior of ink when the nozzle plate of the present invention is used.

FIG. 3 is a diagram showing the behavior of ink when the nozzle plate of the present invention is used.

FIG. 4 is a diagram showing the behavior of ink when the nozzle plate of the present invention is used.

FIG. 5 is a view showing a working example of the present invention.

FIG. 6 is a view showing a working example of the present invention.

FIG. 7 is a sectional view showing a nozzle shape of a conventional example.

[Explanation of symbols]

 1 Nozzle plate 1-a Nozzle plate material 2 Nozzle 2-a Column part 2-b Cone part 2-c Ink ejection port 3 Meniscus 3-a Meniscus 4 Ink 4-a Ink droplet 4-b Ink bureaucracy 5 Ink ejection means 10 Punch 11 Stripper Plate 12 Die 13 Hole 14 Chamfer 15 Cutout 16 Burr 101 Nozzle Plate 102 Nozzle 102-b Ink Inlet 102-c Ink Ejection 103 Meniscus 103-a Meniscus 104 Ink

Claims (2)

[Claims] 1. An ink jet head having a substrate having an ink flow path, means for ejecting ink, and a nozzle plate having nozzles for ejecting the ink, wherein the nozzle is an ink ejection port in the ink ejection direction. A nozzle plate having a funnel shape having a cylindrical portion having a divergence angle of 1 to 10 degrees from a minimum diameter portion and a conical portion having a divergence angle larger than at least the divergence angle of the cylindrical portion. 2. A punch having a funnel shape corresponding to the funnel shape of the nozzle in forming the funnel-shaped nozzle having a minimum diameter of several tens of microns for a metal sheet having a thickness of several hundreds of microns or less, and the punch. A die provided with a hole slightly larger than the small-diameter portion at the tip and a chamfered portion having a volume smaller than the volume at which the punch abuts and penetrates the metal sheet at the hole entrance and the metal sheet swells Grinding the bulged portion formed by abutting and penetrating the metal plate, which is held between the stripper plate for guiding the large-diameter shaft portion of the punch and the die, and the punch. A method for manufacturing a nozzle plate, characterized by removing by processing to obtain a nozzle shape.