JPH06198875A - Ink jet head, mold for flow path substrate of ink jet head, and production of mold for flow path substrate of ink jet head - Google Patents

Abstract

PURPOSE:To obtain superior bubble discharge properties by injection molding by a method wherein in an ink jet head obtained by injection molding at least ink chambers and supply paths, the supply path is equal to the ink chamber in width but smaller than the same in depth. CONSTITUTION:A mold for injection molding a flow path substrate 230 is composed of a flow path molding piece and a peripheral part molding piece. The flow path molding piece is composed of a supply path forming groove provided from one end to the other end and ink chamber wall forming grooves provided from one end to the other end of the flow path molding piece crosswise to the supply path forming groove with a depth larger than that of the same. By using this mold, the flow path substrate 230 is molded with ink chambers 170 separated by ink chamber walls 180, supply paths 35 connected to the ink chambers 170 with a width equal to the ink chamber 170 and a depth smaller than the same, and a common ink reservoir 53. A bubble intruding into the common ink reservoir 53 is sucked into the ink supply path 35 with the suction of ink, depressed from downward in the supply path 35, deformed along a top sealing member, gradually moved toward the outlet of the supply path 35, and led to the ink chamber 170.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-demand type ink jet head for ejecting ink droplets when receiving print data and forming dots on a recording sheet by the ink droplets.

[0002]

2. Description of the Related Art It is necessary to further increase the nozzle density in order to realize the high printing quality required for an on-demand type ink jet head.
As disclosed in Japanese Patent No. 64450, for an inkjet head highly integrated by alternately arranging ink chambers communicating with respective nozzles from opposite sides with respect to a nozzle array formed on a common flow channel substrate. In order to mold this kind of flow path substrate at a low cost, a manufacturing method such as integrally molding by injection molding using a polymer resin material is adopted. ing.

[0003]

However, in such a conventional ink jet head, the polymer resin material of the flow path substrate material easily adsorbs air bubbles, and the width and depth of the supply path are narrowed, so that the air bubble discharging property is reduced. Was particularly bad, and the printing characteristics lacked stability.

In addition, the end mill machining which is a conventional die machining method has a problem in tool durability. Particularly in the processing of a highly integrated flow path substrate for an inkjet head, the tool is minute and wears a lot, and it is difficult to control the size of the cutting groove, which makes it difficult to stably supply a high-precision die.

In addition, the surface condition of the flow path substrate is poor at the contact surface between the molds, causing burrs, cracks, chips, etc. to prevent the close contact between the flow path substrates and the sealing member, and the ink sealing property. It was difficult to secure. Therefore, there is a problem that ink adheres to the peripheral equipment and stains and corrosion occur.

As described above, the conventional highly integrated flow path substrate has a poor bubble discharging property, and it is difficult to seal the ink. Further, there is also a problem that it is difficult to secure dimensional accuracy and stable manufacture of a mold for injection molding the flow path substrate.

[0007]

In order to solve the above problems, an ink jet head, a molding die for a flow path substrate of an ink jet head, and a method for manufacturing a molding die for a flow path substrate of an ink jet head according to the present invention are described in (1) ) A plurality of nozzles, an ink chamber that communicates with the nozzles, a supply path that communicates with the ink chamber, and a common ink reservoir connected to the supply path, and at least the ink chamber and the supply path are injection molded. In the ink jet head manufactured in (1), the supply path has the same width as the ink chamber and is shallow in the depth direction.

(2) A plurality of nozzles, an ink chamber communicating with the nozzles, and a supply path communicating with the ink chambers,
In a molding die for a flow path substrate of an inkjet head, which has a common ink reservoir connected to the supply path, and at least the ink chamber and the supply path are manufactured by injection molding, the molding die is a flow path molding die. A flow path forming die that includes a piece as a part and intersects the supply path forming groove where the flow path forming die piece exits from one end to the other end and the supply path forming groove that is deeper than the supply path forming groove. It is characterized by having an ink chamber wall forming groove that extends from one end of the top to the other end.

(3) a plurality of nozzles, an ink chamber communicating with the nozzles, and a supply path communicating with the ink chambers,
A molding die for a flow path substrate of an inkjet head, which has a common ink reservoir connected to the supply passage, and at least the ink chamber, the supply passage, and the common ink reservoir are manufactured by injection molding, wherein the molding die is claimed. Item 2. The flow path forming die piece and the peripheral forming die piece for forming the common ink reservoir are contacted with each other without a gap, and the contact surfaces are the flow passage forming die piece and the peripheral forming die. It is characterized in that it is placed on the convex portion of the top.

(4) A plurality of nozzles, an ink chamber communicating with the nozzles, and a supply path communicating with the ink chambers,
In a method for manufacturing a molding die for a flow path substrate of an inkjet head, which has a common ink reservoir connected to the supply path, and at least the ink chamber and the supply path are manufactured by injection molding, a supply path forming blade is moved straight. A first step of cutting a flow path forming die piece forming a part of the forming die to form a supply path forming groove that extends from one end of the flow path forming die piece to the other end; and an ink chamber The wall forming blade is advanced straight in a direction intersecting with the supply path forming groove, the flow path forming die piece is cut deeper than the supply path forming groove, and the flow path forming die piece comes out from one end to the other end. And a second step of forming the ink chamber wall forming groove.

(5) In the method of manufacturing a flow path molding die piece according to (4), a first step of cutting the peripheral molding die piece to form a common ink reservoir wall forming groove, A second step of polishing the side surfaces of the flow path molding die piece and the peripheral molding die piece to bring them into contact with each other without a gap, and the flow path molding die piece and the peripheral molding die piece are relatively positioned. And a third step of fixing.

[0012]

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

FIG. 1 shows an ink jet head which is an embodiment of the present invention, FIG. 2 shows a flow path substrate 230 of the ink jet head, and FIG. 3 shows an example of a molding die 340 for injection molding the flow path substrate 230. It is shown.

As shown in FIG. 1, the nozzle 190 is opened in the nozzle plate 33 and connected to the ink chamber 170, and the ink chamber 170 is connected to the common ink reservoir 53 through the supply passage 35. The pressure generating member 150 presses the sealing member 30 by applying a voltage and ejects the ink in the ink chamber 170 sealed by the sealing member 30 from the nozzle 190. The flow path substrate 230 includes an ink chamber 170, a supply path 35,
A common ink reservoir 53 is provided.

A molding die 340 for injection molding the flow path substrate 230 is, as shown in FIG. 3, a flow path molding die piece 34.
1 and a peripheral molding die piece 342, which are in contact with each other without a gap, and the contact surface 280 has a flow path forming die piece 34.
It is arranged between the convex portion 57 of No. 1 and the convex portion 58 of the peripheral molding die piece 342.

As shown in FIG. 4, the flow path forming die piece 341 has a supply passage forming groove 343 which extends from one end 260 to the other end 261 thereof, and is deeper than the supply passage forming groove 343 and intersects with the supply passage forming groove 343. An ink chamber wall forming groove 344 is formed from one end 263 of the path forming die piece 341 to the other end 262.
As shown in FIG. 5, the flow path forming mold piece 341 is moved straight in the direction of the arrow by using a pre-programmed automatic processing machine or the like for the supply path forming blade 345 to move the flow path forming mold piece 34.
After the step of cutting 1 from its one end 260 to the other end 261 and processing the supply path forming groove 343, as shown in FIG. 6, the ink chamber wall forming blade 346 is processed by the same automatic processing machine or the like. , Go straight from location a to location b,
The flow path forming mold piece 341 is moved from one end 263 to the other end 26 thereof.
The ink chamber wall forming groove 344 is processed by cutting up to 2 and cutting deeper than the supply passage forming groove 343. Next, the ink chamber wall forming blade 346 is moved straight in the opposite direction from B to B, returns to the original position, and when it reaches B, moves to C and straightens and cuts toward D again to form the ink chamber wall forming groove 344. It is manufactured by the manufacturing method of the step of forming a plurality of. Flow path mold die 34
Ink chamber wall forming blade 3 so that convex portions 57 are left on both ends of
It is desirable that the cutting of 46 proceeds from the inside.

As described above, the flow path molding die piece 34 is used.
In the manufacturing method of No. 1, since the supply path forming blade 345 and the ink chamber wall forming blade 346 move linearly from one end of the flow path forming die piece 341 to the other end for processing, the supply path forming blade 345.
The width W of the ink chamber wall forming blade 346 does not need to be thin as in the end mill tip, and may be fine in the cutting width direction (y direction). As a result, it becomes possible to have a sufficient length L in the cutting direction (x direction), and it becomes possible to greatly improve the durability of the supply path forming blade 345 and the ink chamber wall forming blade 346. Is less likely to wear, and it is possible to always supply the flow path molding die piece 341 with high accuracy.

Further, the machining can be completed without moving the tool in the cutting depth direction (z direction). Therefore, the repetitive operation error in the z direction of the automatic processing machine does not occur, the accuracy of the depth of the supply path forming groove 343 and the ink chamber wall forming groove 344 is improved, and the forming die of the high density inkjet head can be processed for the first time. It became. In particular, the depth of the supply path forming groove 343 is transferred to the supply path 35 during injection molding,
It is an important parameter that determines the characteristics such as the discharge speed and the discharge amount, and such a supply path forming groove 343 can be realized for the first time by the processing method.

The supply path forming blade 345 and the ink chamber wall forming blade 346 may have various shapes. As an example, the ink chamber wall forming blade 346 having a stepped shape as shown in FIG. 7 can form a corner in the bottom smear of the ink chamber 170 to prevent bubble accumulation.

As shown in FIG. 8, the other peripheral molding die piece 342 is formed by cutting the peripheral molding die piece 342 with an end mill 71 to form a common ink reservoir wall forming groove 347 and a nozzle plate positioning hole forming projection. 348 and the positioning pin hole 349 are manufactured in the process of processing. End mill 7
For No. 1, proceed with the processing while selecting the diameter that suits each processing. The inner side is slightly cut so as to leave the convex portion 58 near the contact surface with the flow path molding die piece 341.

As shown in FIG. 9, the molding die 340 polishes the side surface 270 of the flow path portion molding die piece 341 and the side surface 271 of the peripheral portion molding die piece 342 manufactured as described above by lapping or the like. And contacting both without a gap,
By adjusting the positions of the flow path forming mold piece 341 and the peripheral forming mold piece 342, the height difference h between the bottom of the ink chamber wall forming groove 344 and the bottom of the peripheral forming mold piece 342 is set to zero, and both are screwed. It is manufactured by the process of fixing with etc.

When a high-temperature polymer resin is poured into the molding die 340 thus manufactured, and pressurized and filled, the irregularities of the molding die 340 are directly transferred to the flow path substrate 230, and the ink chamber wall forming groove 344 is formed. The ink chamber wall 180, the supply path forming groove 343 are the supply path 35, and the nozzle plate positioning hole forming projection 348 is the nozzle plate positioning hole 35.
0 for the drive unit positioning pin 351 for the drive unit positioning hole 3
Each of 52 is transferred to the flow path substrate 230. In this manner, the ink chamber 170 separated by the ink chamber wall 180, the supply path 35 communicating with the ink chamber 170, and the common ink reservoir 53 communicating with the supply path 35 are formed in the flow path substrate 230.

One of the features of the present invention resides in the shape of the supply passage 35 thus constructed, and the shape is equal to the width of the ink chamber 170 and the depth thereof is the ink as shown in FIG. It is shallower than the chamber 170. Such a supply path 35 promotes the flow of bubbles, and promotes the removal of bubbles in the flow path (which indicates the common ink reservoir 53, the supply path 35, and the ink chamber 170). Therefore, the effect of stabilizing the ink ejection characteristics is produced. This effect will be described in more detail with reference to FIG. 11. The bubbles 2 mixed in the common ink reservoir 53
10 is sucked into the supply path 35 by suction of ink and reaches the entrance of the supply path 53. Since the supply passage 53 is squeezed in the depth direction, the bubbles 210 are crushed from below, deformed along the sealing member 30 on the upper surface of the ink chamber 170, and gradually proceed toward the outlet direction of the supply passage 53. Go out. (Air bubbles 211 in the figure) When reaching the outlet of the supply path 53, the ink chamber 17
The bubble spreads to 0 (bubble 212 in the figure) In this series of flow, the bubble always moves linearly along the surface of the sealing member 30, so that the force that hinders the flow of the bubble is weak and the bubble is easily discharged.

The present invention is also characterized by the shape of the molding die near the contact surface between the flow path molding die piece 341 and the peripheral portion molding die piece 342. As shown in FIG. The periphery of the surface 280 is surrounded by the convex portions 57 and 58. This convex shape hides defects such as burrs, cracks, and chips generated on the surface of the flow path substrate 230 in the vicinity of the contact surface 280 of the molding die 340 in the groove 353 (see FIG. 2), and as a result,
As shown in FIG. 12, the flow path substrate 230 and the sealing member 30 are
Adhere to each other on both sides of the groove 353, and the ink sealing property of the ink chamber 170 is secured. On the other hand, the contact surface 28 of the molding die 340
Burrs and cracks generated on the surface of the flow path substrate 230 near 0,
Surface roughness such as chipping is hidden by the bottom portion 285 of the groove 353 and does not contact the sealing member 30, so that such defects that occur during manufacturing do not affect the ink sealability. The depth of the groove 353 is preferably such that the roughness of the surface is sufficiently buried.

The present invention is a nozzle 19 as shown in FIG.
Channel substrate 230 in which 0 is integrally molded with the channel substrate 230
Can also be applied to.

[0026]

The present invention described above has the following effects.

(1) Since the durability of the tool can be greatly improved, it is possible to stably supply a high precision molding die. As a result, it is possible to provide an inkjet head having a high density and less variation in ejection characteristics.

(2) Even in an injection-molded ink jet head in which air bubbles are relatively hard to flow, since the supply passage partially penetrates the ink chamber in a cross section, the air bubbles easily flow along the cross section. Therefore, it becomes possible to provide an inkjet head having excellent bubble discharging property by injection molding.

(3) The ink sealing property for sealing the flow path substrate is not affected by the surface roughness of the flow path substrate in the vicinity of the mold contact surface, and ink leakage does not occur. As a result, the reliability of the inkjet head and its peripheral equipment is improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an inkjet head of the present invention.

FIG. 2 is a perspective view of a flow path substrate of the inkjet head of the present invention.

FIG. 3 is a perspective view of a molding die for a flow path substrate of the inkjet head of the present invention.

FIG. 4 is a perspective view of a flow path part molding die piece of the present invention.

FIG. 5 is a perspective view illustrating a manufacturing process of the flow path part molding die piece of the present invention.

FIG. 6 is a perspective view illustrating a manufacturing process of the flow path part molding die piece of the present invention.

FIG. 7 is a perspective view showing an example of an ink chamber wall forming blade.

FIG. 8 is a perspective view illustrating a manufacturing process of a peripheral molding die piece of the present invention.

FIG. 9 is a perspective view illustrating a manufacturing process of the molding die of the present invention.

FIG. 10 is an ink chamber of the inkjet head of the present invention,
It is a perspective view of a supply path.

FIG. 11 is a perspective view illustrating the flow of bubbles.

FIG. 12 is a perspective view illustrating an effect of a groove.

FIG. 13 is a perspective view showing an ink jet head of another embodiment of the present invention.

[Explanation of symbols]

 30: Sealing member 53: Common ink reservoir 58: Convex portion 71: End mill 170: Ink chamber 210: Bubbles 211: Bubbles 212: Bubbles 230: Flow path substrate 260: End face 261 End surface 262 ... End surface 263 ... End surface 280 ... Contact surface 281 ... Contact surface 285 ... Bottom 340 ... Molding mold 341 ... Flow path molding mold piece 342 ... Peripheral molding mold piece 343 ... Supply Channel forming groove 344 ... Ink chamber wall forming groove 345 ... Supply path forming blade 346 ... Ink chamber wall forming blade 347 ... Common ink reservoir wall forming groove 348 ... Nozzle plate positioning hole forming projection 349 ... For positioning pin Hole 350 ··· Nozzle plate positioning hole 351 ··· Drive unit positioning pin 352 ··· Drive unit positioning hole 353 ... Groove 354 ... Bottom of ink chamber wall forming groove

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Claims (5)

[Claims] 1. A nozzle having a plurality of nozzles, an ink chamber communicating with the nozzle, a supply path communicating with the ink chamber, and a common ink reservoir connected to the supply path, and at least the ink chamber and the supply path. In the inkjet head for manufacturing by means of injection molding, the supply path has the same width as the ink chamber and is shallow in the depth direction. 2. A nozzle having a plurality of nozzles, an ink chamber communicating with the nozzle, a supply path communicating with the ink chamber, and a common ink reservoir connected to the supply path, and at least the ink chamber and the supply path. In a molding die for a flow path substrate of an inkjet head, which is manufactured by injection molding, the molding die partially includes a flow path molding die piece, and the flow path molding die piece extends from one end to the other end. An ink jet characterized by having a supply path forming groove that exits and an ink chamber wall forming groove that intersects the supply path forming groove deeper than the supply path forming groove and that exits from one end to the other end of the flow path forming die piece. Mold for the flow path substrate of the head. 3. A nozzle having a plurality of nozzles, an ink chamber communicating with the nozzle, a supply passage communicating with the ink chamber, and a common ink reservoir connected to the supply passage, and at least the ink chamber and the supply passage. And a molding die for a flow path substrate of an inkjet head for manufacturing the common ink reservoir by injection molding, wherein the molding die is a peripheral molding die for molding the flow channel molding die piece and the common ink reservoir. A molding die for a flow path substrate of an ink jet head, characterized in that the molding die is configured to be in contact with each other without a gap, and the contact surfaces are arranged on the convex portions of the flow path molding die piece and the peripheral molding die piece. Type. 4. A nozzle having a plurality of nozzles, an ink chamber communicating with the nozzle, a supply path communicating with the ink chamber, and a common ink reservoir connected to the supply path, and at least the ink chamber and the supply path. In a method of manufacturing a molding die for a flow path substrate of an inkjet head, which is manufactured by injection molding, a feed path forming blade is moved straight, and a flow path molding die piece forming a part of the molding die is cut. A first step of forming a supply path forming groove that extends from one end of the flow path forming die to the other end; and a step of moving the ink chamber wall forming blade straight in a direction intersecting the supply path forming groove to form the flow path forming groove. And a second step of cutting the die piece deeper than the supply passage forming groove to form an ink chamber wall forming groove that extends from one end to the other end of the flow passage forming die piece. Molding of flow path substrate for inkjet head Type method of manufacturing. 5. The method of manufacturing a flow path molding die piece according to claim 4, wherein the peripheral molding die piece is cut to form a common ink reservoir wall forming groove; A second step of grinding the side surfaces of the molding die piece and the peripheral molding die piece to bring them into contact with each other without a gap; and fixing the flow path molding die piece and the peripheral molding die piece relatively in position. A method of manufacturing a molding die for a flow path substrate of an inkjet head, comprising: a third step.