JP3170805B2 - Inkjet recording head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an ink jet recording head.

[0002]

2. Description of the Related Art Conventionally, a nozzle portion of an ink jet recording head is formed integrally with an ink jet recording head substrate, or a nozzle plate having a nozzle portion formed separately from the ink jet recording head substrate is provided with pressure chambers and ink passages. Is formed on the surface of the ink jet recording head substrate on which is formed.

FIGS. 13 and 14 are a front view and a cross-sectional view taken along line CC, respectively, showing the structure of the nozzle surface of a conventional ink jet recording head in which the nozzle portion is formed separately from the ink jet recording head substrate. In the figure, an ink jet recording head substrate 1 in which nozzles 2 are formed corresponding to the ink channels 3 on an ink jet recording head substrate 1 in which ink channels 3 are formed by injection molding a polymer material such as a plastic resin.
A nozzle plate 4 made of a different material from the above is bonded by an adhesive 6.

[0004]

In order to realize high printing quality and always obtain a stable printing effect in an ink jet recording head, it is necessary to always discharge ink from a nozzle perpendicularly to a nozzle surface. .

However, when the nozzle plate is made of a polymer material such as a plastic resin, the durability against mechanical destruction of the peripheral portion of the nozzle such as paper rubbing and paper jam is poor.
The nozzle plate itself may be destroyed. As a result, when the nozzle surface is broken and the ink is ejected from the nozzle, there is a possibility that the ink is not ejected perpendicularly to the nozzle surface. For this reason, the nozzle plate is preferably made of a material having abrasion resistance, for example, metal. However, in the conventional structure in which the nozzle plate and the ink jet recording head substrate are formed of different materials and adhered to each other, since the two materials have different coefficients of thermal expansion, distortion occurs in the bonded portion, the nozzle plate warps, and further, the ink jet recording head substrate There is a possibility that the nozzle plate may come off. As a result, the nozzles and the nozzle axis are deformed, and the ejection direction of the ink is changed, which may affect the scattering of the ink and the high printing quality.

For this reason, there is a problem that an expensive adhesive which makes it difficult for the nozzle plate to peel off from the ink jet recording head substrate must be selected, and that the nozzle plate must be divided into a plurality of pieces and bonded to each nozzle or every several nozzles. Was.

Accordingly, the present invention is to solve such a conventional problem. It is an object of the present invention to prevent the nozzle plate from warping with respect to the ink jet recording head substrate and to prevent the nozzle surface from being physically damaged. , On production,
An object of the present invention is to provide an ink jet recording head which can be easily formed.

[0008]

According to the present invention, there is provided an ink jet recording head comprising: a nozzle plate having nozzles for discharging ink; and a substrate having pressure chambers and ink passages communicating with the nozzles. In the ink jet recording head formed by joining, the nozzle plate and the substrate have different thermal expansion coefficients, and a peripheral portion of the nozzle plate is expanded near the nozzle , or the peripheral portion is expanded.
A penetrated slit or hole in which a round portion is formed in the portion is formed . Further, the slit is formed in a direction perpendicular to the nozzle row. Further, the slits are arranged on both sides of the nozzle row in a symmetrical manner. Further, the slits are arranged in a staggered manner on both sides of the nozzle row.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1, 2 and 3 are structural views showing an embodiment of the ink jet recording head of the present invention. FIG. 1 is a front view, and FIG. 2 is a sectional view taken along line AA of FIG. FIG.
Shows a cross-sectional view taken along line BB in FIG.

In FIG. 1, a nozzle plate 4 having nozzles 2 corresponding to the ink flow paths 3 is adhered to a front surface of an ink jet recording head substrate 1 having an ink flow path 3 formed of a polymer material such as a plastic resin. To form a flow path. The nozzle plate 4 is made of a material different from that of the ink jet recording head substrate 1, and a nozzle 2 is formed by making a hole in a metal plate by etching and pressing. Further, slits 5, which are features of the present invention, are formed on both sides of the nozzle row.

According to the above structure, the distortion in the adhesive 6 caused when the nozzle plate 4 having a different coefficient of thermal expansion and the ink jet recording head substrate 1 are bonded to each other is alleviated by the slit 4, and the warpage of the nozzle plate 4 and the distortion of the nozzle plate 4 are reduced. Peeling from the inkjet recording head substrate 1 can be prevented. As a result, the nozzle 2 is not deformed, the nozzle shaft 7 is tilted, and the ink ejection direction does not change, stable ink ejection is performed, and high printing quality is obtained.

Further, since the nozzle plate 4 can be made of a different material from that of the ink jet recording head substrate 1 in production, the degree of freedom in selecting the material is increased, and the nozzle plate 4 and the ink jet recording head substrate 1 are integrally formed. This leads to a reduction in manufacturing costs.

The depth of the slit 5 in FIGS. 2 and 3, that is, the thickness t of the nozzle plate 4 is not less than 5 μm and not more than 500 μm.
The following degree is desirable. Further, the relationship between the thickness w of the slit 5 and the depth t of the slit 5 needs to be 2 ≦ w / t ≦ 20. If w / t is too small, foreign matter such as paper dust or dust enters the inside of the slit 5, or if the surface of the nozzle plate 4 is rubbed with a blade for removing foreign matter such as a rubber plate, foamed resin, etc. Do not enter the slit 5 and the foreign matter is not completely removed.

FIGS. 4, 5 and 6 are front views showing an embodiment of the arrangement structure of the slits of the nozzle plate. FIG. 4 shows an example in which the slits 5 are arranged on both sides of the nozzle row perpendicularly to the nozzle row in left-right contrast, FIG. FIG.
Is an example in which the slits 5 are extended to the nozzle row side in the arrangement structure of FIG. According to the above structure, the distortion of the bonding portion in the nozzle row direction is reduced by the slits 5 arranged perpendicular to the nozzle row.

FIG. 7 is a sectional view showing an embodiment of the structure of the slit of the nozzle plate. In the figure, the convex corner 5a of the step of the slit 5 of the nozzle plate 4 is formed by a tapered surface having an angle θ. According to the above structure, foreign matter that has entered the inside of the slit 5 can be easily removed without remaining in the slit 5 by a removing method such as wiping. The angle θ of the tapered surface is desirably 15 ° ≦ θ ≦ 75 °, and the smaller the angle θ, the higher the foreign matter removing ability.

FIGS. 8 and 9 are sectional views showing an embodiment of the structure of the step portion of the slit of the nozzle plate. FIG. 8 shows an embodiment in which the convex corners 5 a of the steps of the slit 5 are rounded,
FIG. 9 shows an embodiment in which the convex corner 5a and the concave corner 5b of the step are rounded. According to the above structure, when removing foreign matter such as wiping, the foreign matter does not get caught on the corner due to the roundness of the corner of the step portion of the slit 5. Therefore, the foreign matter removal ability can be further improved. Further, the abrasion of the blade for removing foreign matter due to the stepped convex portion 5a of the slit can be suppressed, and the durability can be improved.

FIGS. 10 and 11 are sectional views showing an embodiment of the structure of the nozzle plate bonding method. In FIG. 10, the adhesive 6 for bonding the inkjet recording head substrate 1 and the nozzle plate 4 protrudes from the inside of the slit 5 to the surface of the nozzle plate 4. In FIG. 11, the protruding adhesive 6 spreads on the surface of the nozzle plate 4. According to the above structure, the convex corner 5a and the concave corner 5b of the step of the slit 5 are hidden by the adhesive, so that the wear of the foreign matter removing blade due to the corner can be suppressed as in the structure of FIG. And durability can be improved. Further, the effect can be obtained only by changing the bonding method without processing the corner of the slit, so that the production convenience is improved. In FIG. 11, the nozzle plate 4 is sandwiched by the adhesive 6 due to the spread of the adhesive 6 on the surface of the nozzle plate 4, and the close contact between the nozzle plate and the ink jet recording head substrate is improved.

FIG. 12 is a front view showing an embodiment of the structure of the nozzle plate. In the figure, a plurality of holes 8 are provided on the nozzle plate 4 instead of the slits 5 in FIG. According to the above structure, the holes 8 can be provided at various positions from the rectangular slits 5, so that the degree of freedom in processing the holes 8 is widened, and the size of the holes 8 can be set freely.

[0020]

According to the ink jet head of the present invention, a nozzle plate formed with nozzles for discharging ink is joined to a substrate formed with a pressure chamber and an ink flow path communicating with the nozzles. In the ink jet recording head, the nozzle plate and the substrate have different coefficients of thermal expansion, and a penetrating slit in which a peripheral portion is expanded near the nozzle of the nozzle plate or a rounded portion is formed in the peripheral portion. Or, by forming the holes, the nozzle plate and the substrate are prevented from being distorted or peeled off by bonding with an adhesive to realize good ejection characteristics, and the peripheral edge of the slit or the hole is expanded or the peripheral edge is expanded. Due to the formation of the rounded portion, foreign substances deposited inside the slits and holes can be easily removed, and the above-mentioned ejection characteristics can be extended. It is possible to maintain over.

[0021]

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of an ink jet recording head of the present invention.

FIG. 2 is a sectional view showing an embodiment of the ink jet recording head of the present invention.

FIG. 3 is a sectional view showing an embodiment of the ink jet recording head of the present invention.

FIG. 4 is a front view showing an embodiment of an arrangement structure of slits of a nozzle plate.

FIG. 5 is a front view showing an embodiment of the arrangement structure of the slits of the nozzle plate.

FIG. 6 is a front view showing an embodiment of an arrangement structure of slits of a nozzle plate.

FIG. 7 is a sectional view showing an embodiment of the structure of the step portion of the slit of the nozzle plate.

FIG. 8 is a sectional view showing an embodiment of the structure of the step portion of the slit of the nozzle plate.

FIG. 9 is a sectional view showing an embodiment of the structure of the step portion of the slit of the nozzle plate.

FIG. 10 is a sectional view showing an embodiment of the structure of the nozzle plate bonding method.

FIG. 11 is a sectional view showing an embodiment of the structure of the nozzle plate bonding method.

FIG. 12 is a front view showing an embodiment of the structure of the nozzle plate.

FIG. 13 is a front view showing a structure of a nozzle surface of a conventional ink jet recording head.

FIG. 14 is a cross-sectional view illustrating a structure of a nozzle surface of a conventional inkjet recording head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink jet recording head substrate 2 Nozzle 3 Ink flow path 4 Nozzle plate 5 Slit 5a Convex corner 5b Concave corner 6 Adhesive 7 Nozzle shaft 8 Hole

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-78560 (JP, A) JP-A-64-64856 (JP, A) JP-A-63-82391 (JP, U) JP-A-1 176971 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B41J 2/135

Claims (4)

(57) [Claims] 1. An ink jet recording head in which a nozzle plate in which nozzles for discharging ink are formed and a substrate in which a pressure chamber communicating with the nozzle and an ink flow path are formed are joined. And the substrate have a different coefficient of thermal expansion, and the periphery of the nozzle plate near the nozzle is
An ink jet recording head having an expanded or a perforated slit or hole formed with a rounded portion at the periphery . 2. The ink jet recording head according to claim 1, wherein said slit is formed in a direction perpendicular to a nozzle row. 3. The ink jet recording head according to claim 2, wherein said slits are arranged on both sides of a nozzle row in a symmetrical manner. 4. The ink jet recording head according to claim 2, wherein said slits are arranged in a staggered manner on both sides of a nozzle row.